Anselm Schulz

• Acke, Manou; Keelson, Benyameen; Engseth, Lars; Øhrn, Frank-David; Gompel, Gert Van & Röhrl, Stephan Maximilian Herbert [Vis alle 9 forfattere av denne artikkelen] (2026). Precision of an automated surface-based CT-RSA (asCTRSA) for assessing tibial implant migration: a porcine cadaver study and a clinical case. Acta Orthopaedica. ISSN 1745-3674. 97, s. 484–490. doi: 10.2340/17453674.2026.46156. Fulltekst i vitenarkiv Vis sammendrag

  Background and purpose: Radiostereometric analysis (RSA) is the reference standard for migration analysis, but adoption is limited by invasive marker implantation and specialized equipment. We developed an automated, surface-based CT-RSA (asCTRSA) method that reports a registration quality measure (mean rigid-body fitting error, ME). Our aim was to evaluate the precision by comparing asCTRSA with marker-based RSA and CT-based Micromotion Analysis (CTMA, v25.1). Methods: Precision was assessed in a retrospective, repeated-measures, zero-migration study using a porcine cadaver tibial implant scanned in 7 positions (21 double examinations). Migration was reported as maximum total point motion (MTPM) for RSA and asCTRSA. CTMA provided maximum total translation (mTT) as an estimate of MTPM. Mean rigid-body fitting error (ME) was calculated for RSA and asCTRSA (acceptability threshold 0.35 mm). The minimal important difference for MTPM/mTT was 0.1 mm. asCTRSA was applied to 1 clinical case with known migration 3 and 8 months postoperatively (NCT04017533). Results: In the porcine study, precision was 0.09 mm (95% confidence interval [CI] 0.02–0.18) for asCTRSA, 0.08 mm (CI 0.03–0.12) for CTMA, and 0.45 mm (CI 0.20–0.69) for RSA. In the clinical case, asCTRSA detected increasing migration (MTPM 2.5–3.6 mm) and exceeded CTMA’s mTT by 0.4 mm at 8 months. Mean rigid-body fitting error remained below 0.35 mm. Conclusion: We showed that asCTRSA enables automated, surface-based CT-RSA and demonstrated higher precision than RSA in this zero-migration cadaver setting.

• Alves, Natalia; Schuurmans, Megan; Rutkows, Dawid; Saha, Anindo; Vendittelli, Pierpaolo & Obuchowski, Nancy [Vis alle 115 forfattere av denne artikkelen] (2026). Artificial intelligence and radiologists in pancreatic cancer detection using standard of care CT scans (PANORAMA): an international, paired, non-inferiority, confirmatory, observational study. The Lancet Oncology. ISSN 1470-2045. 27(1), s. 116–124. doi: 10.1016/S1470-2045(25)00567-4. Fulltekst i vitenarkiv
• Bru, Fredrik; Engseth, Lars; Pripp, Are Hugo; Schulz, Anselm; Aae, Tommy Frøseth & Husby, Vigdis Kvitland Schnell [Vis alle 9 forfattere av denne artikkelen] (2026). Dose reduction does not impact precision of CT-RSA in tibial components in total knee arthroplasty: a randomized controlled trial. Journal of Orthopaedic Surgery and Research. doi: 10.1186/s13018-026-06801-8. Fulltekst i vitenarkiv Vis sammendrag

  Purpose Radiostereometric analysis (RSA) has been the gold standard for implant migration analysis for decades. Our group previously demonstrated in a porcine cadaver model that CT-RSA precision was non-inferior by dose reduction. The aim of this study was to investigate whether this finding applied in a clinical setting. Methods This study is part of the ClessTKA trial comparing a novel 3D printed uncemented medially stabilized total knee arthroplasty (TKA) with Tritanium TKA. Fifty patients were recruited (GMK Sphere n = 26, Tritanium n = 24). All surgeries were performed with mechanical alignment between January and June 2023. CT acquisitions were performed postoperatively within 2 days (standard dose 0.05 mSv, n = 49) and at 1 year (low dose 0.01 mSv, n = 47) using a GE Revolution scanner. CT-RSA analyses of tibial components were performed with Sectra CTMA software by a certified assessor. The primary endpoint was difference in precision (mean) of maximum total point motion (MTPM) between dose levels, with an equivalence interval of 0–0.1 mm. Results Mean difference (95% CI) in MTPM under zero motion circumstances between standard and low dose was 0.007 mm (− 0.018 to 0.032). No clinically meaningful differences were found for migration or rotations. Centre-of-mass analysis showed one significant but clinically irrelevant posterior translation (0.013 mm). Conclusion The findings confirm that reducing the effective radiation dose from 0.05 mSv to 0.01 mSv does not compromise the precision of CT-RSA for tibial components in TKA. The results further support the use of low-dose CT-RSA protocols in clinical studies, enabling substantial reduction in patient radiation exposure without loss of precision. Trial registration Clinicaltrials.gov identifier NCT05651009. Initial release of the study was November 23, 2022. At that time, the software CTMA (Sectra) did not provide the very important Maximum Total Point Motion (MTPM), this was introduced in a later update of the CTMA. Hence there was change in the original protocol retrospectively.

• Hansen, Vinjar Brenna; Schulz, Anselm; Hellum, Christian & Röhrl, Stephan Maximilian Herbert (2026). Movement of the sacroiliac joint during a modified active straight leg raise measured with CT-RSA: a feasibility study. Acta Orthopaedica. ISSN 1745-3674. 97, s. 151–155. doi: 10.2340/17453674.2026.45479. Fulltekst i vitenarkiv
• Hanekamp, Bettina Andrea; Viktil, Ellen; Dormagen, Johann Baptist; Kløw, Nils Einar; Brunborg, Cathrine & Malinen, Eirik [Vis alle 8 forfattere av denne artikkelen] (2026). Optimal time for MRI response evaluation in squamous cell carcinoma of the anus. BJR Open. 8(1). doi: 10.1093/bjro/tzag004. Fulltekst i vitenarkiv
• Poulsen, Magnus; Röhrl, Stephan Maximilian Herbert; Schulz, Anselm & Stødle, Are Haukåen (2025). Prospective Validation of a Weightbearing CT Stability Threshold for Subtle Lisfranc Injuries. Foot & ankle international. ISSN 1071-1007. 46(12), s. 1386–1394. doi: 10.1177/10711007251374674. Fulltekst i vitenarkiv Vis sammendrag

  Background: Accurate evaluation can be challenging in subtle Lisfranc injuries. Although weightbearing computed tomography (WBCT) provides 3-dimensional assessment under physiological load, its role in diagnosing subtle Lisfranc instability and guiding treatment thresholds remains undefined. Currently there is no consensus on the optimal timing, measurement protocol, or stability threshold with WBCT. Methods: We prospectively recruited patients with nondisplaced (<2 mm), intra-articular fractures and/or avulsion fractures in the tarsometatarsal 1-3 area. To assess Lisfranc joint stability, patients underwent bilateral, single-leg WBCT scans. Medial cuneiform (C1) and second metatarsal (M2) measurements, evaluating the integrity of both the dorsal and interosseous Lisfranc ligament, were combined and compared to the contralateral, healthy side to create a difference score. Threshold of instability was defined as >3 mm C1-M2 difference score. Measurements were tested for agreement using the intraclass correlation coefficient (ICC). Results: 38 patients were included in the study and were able to fully weightbear after a median of 9 days postinjury. Eight patients (21%) had a C1-M2 difference score >3 mm (95% CI, 3.8-5.8) while loading. Instability was confirmed in all 8 patients during a fluoroscopic stress test. The remaining 30 patients, with a C1-M2 difference score <3 mm (95% CI, 0.6-1.1), were classified as stable and received conservative treatment. These patients were followed up with an additional WBCT scan after 12 weeks, and none had signs of Lisfranc instability with a median different score 0.6 mm (95% CI, 0.4-0.7). Our measurement method demonstrated excellent interrater (ICC 0.95, 95% CI, 0.93-0.96) and intrarater agreement (ICC 0.97, 95% CI, 0.96-0.98). Conclusion: For subtle Lisfranc injuries, adequate WBCT can be performed 9 days postinjury. In our study population, using our dual-measuring method, a C1-M2 difference >3 mm on WBCT reliably identified subtle Lisfranc instability.

• Øhrn, Frank-David; Engseth, Lars; Pripp, Are Hugo; Aae, Tommy Frøseth; Schulz, Anselm & Husby, Otto Schnell [Vis alle 7 forfattere av denne artikkelen] (2025). Computed tomography-based radiostereometric analysis achieves sufficient precision for femoral implants in total knee arthroplasty: a randomized controlled trial. Journal of Orthopaedic Surgery and Research. 20(1). doi: 10.1186/s13018-025-06517-1. Fulltekst i vitenarkiv Vis sammendrag

  Background Conventional radiostereometric analysis (RSA) has been used for several decades to assess implant migration in total knee arthroplasty (TKA). More recently, computed tomography–based radiostereometric analysis (CT-RSA) has been introduced as an alternative. Experimental studies have demonstrated acceptable precision for CT-RSA; however, this has not yet been validated in a clinical setting. With the emergence of new alignment philosophies in TKA, migration analysis of femoral components has become increasingly important. A key criticism of CT-RSA has been the higher radiation doses compared with conventional RSA, particularly in longitudinal studies involving repeated CT scans. In this study, we evaluated the precision of CT-RSA for assessing femoral component migration in two TKA designs at two different radiation dose levels. We hypothesized that there would be no clinically relevant difference in precision between the two radiation dose levels. Methods We performed a randomized controlled trial of 50 patients using Tritanium and GMK Sphere 3D Metal implants and analysed the precision of the method through double examinations expressed as means with 95% confidence intervals at standard and low-dose levels. The main outcome variable was the difference in mean maximum total point motion. We set the clinical meaningful difference to be more than 0.1 mm based on existing literature. Secondary outcome variables were the means and standard deviations of the translation and rotation of the implants. Findings We found a precision of (mean, standard deviation) 0.20 (0.08) and 0.17 mm (0.06) for standard and low dose respectively, giving a difference (95% confidence interval) of − 0.03 mm (− 0.06–0.00). P-value was 0.031. Variability ratios were 0.009 for the standard deviation test. Interpretation In this first clinical study to assess the precision of computed tomography–based radiostereometric analysis for femoral implants in total knee arthroplasty, we found no clinically relevant difference in precision. Our findings confirm that CT-RSA provides sufficient precision in a clinical setting to enable migration analysis of femoral implants in total knee arthroplasty, even when using very low radiation doses.

• BONDT, Maaike R. DE; Øhrn, Frank-David; Engseth, Lars; Schulz, Anselm; Kaptein, Bart L. & Röhrl, Stephan Maximilian Herbert [Vis alle 7 forfattere av denne artikkelen] (2025). Precision evaluation of 2 CT-based radiostereometric analysis systems in a cadaver study. Acta Orthopaedica. ISSN 1745-3674. 96, s. 867–872. doi: 10.2340/17453674.2025.44949. Fulltekst i vitenarkiv Vis sammendrag

  Background and purpose: To address the limitations of radiostereometric imaging and to eliminate the need for intraoperative marker placement, CT-based radiostereometric analysis (CT-RSA) software systems have been developed. We aimed to evaluate the precision of a novel CT-RSA software system, V3MA, against an established CT-RSA software system, CTMA, while also examining the impact of CT scanner model on precision. Methods: 7 CT scans per scanner (Siemens SOMATOM Force and GE Revolution) of a porcine cadaver with a knee implant were used for pairwise comparisons. By aligning paired CT scans, the translation (mm), rotation (°), and maximum total point motion (MTPM, mm) of the tibial implant with respect to the bone were computed. V3MA aligned the scans using the voxel gray values of the bone and implant, whereas CTMA aligned the surface points of the bone and implant. The precision of both software systems and the effect of both scanner models were investigated using paired data in a linear mixed model. Results: Both software systems resulted in a similar MTPM (contrast V3MA–CTMA –0.002 mm, 95% confidence interval [CI] –0.015 to 0.011; V3MA: 0.09 mm; CTMA: 0.10 mm), indicating comparable precision using a minimal important difference of 0.10 mm. Using Siemens scanner data resulted in a higher estimated MTPM than using GE scanner data (contrast Siemens–GE 0.046 mm, CI 0.024–0.067; Siemens: 0.12 mm; GE: 0.072 mm). Conclusion: The precision of the new CT-RSA software system, V3MA, is comparable to that of CTMA under zero-motion assumptions. Minor, clinically irrelevant, inter-scanner differences in CT-RSA precision exist for both software systems.

• Viktil, Ellen; Hanekamp, Bettina Andrea; Nesbakken, Arild; Sjo, Ole Helmer; Negård, Anne & Dormagen, Johann Baptist [Vis alle 7 forfattere av denne artikkelen] (2025). Bisacodyl micro-enema before MRI of rectal tumors: effects on rectum, image quality and patient acceptance. European Radiology. ISSN 0938-7994. doi: 10.1007/s00330-025-11996-1. Fulltekst i vitenarkiv
• Njølstad, Tormund Salvesen; Jensen, Kristin; Andersen, Hilde Kjernlie; Berstad, Audun Elnæs; Hagen, Gaute & Johansen, Cathrine Kiperberg [Vis alle 13 forfattere av denne artikkelen] (2025). Deep learning reconstruction for detection of liver lesions at standard-dose and reduced-dose abdominal CT. European Radiology. ISSN 0938-7994. 35(10), s. 6140–6149. doi: 10.1007/s00330-025-11596-z. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Objectives Deep learning reconstruction (DLR) has shown promising image denoising ability, but its radiation dose reduction potential remains unknown. The objective of this study was to investigate the diagnostic performance of DLR compared to iterative reconstruction (IR) in the detection of liver lesions at standard-dose and reduced-dose CT. Materials and methods Participants with known liver metastases from gastrointestinal and pancreatic adenocarcinoma were prospectively included from routine follow-up (October 2020 to March 2022). Participants received standard-dose CT and two additional reduced-dose scans during the same contrast administration, each reconstructed with IR and high-strength DLR. Two radiologists evaluated images for the presence of liver lesions, and a third established a reference standard. Diagnostic performance was compared using McNemar’s test and mixed effects logistic regression. Results Forty-four participants (mean age 66 years ± 11 [standard deviation], 28 men) were evaluated with 348 included liver lesions ≤ 20 mm (297 metastases, 51 benign; mean size 9.1 ± 4.3 mm). Mean volume CT dose index was 14.2, 7.8 mGy, and 5.1 mGy. Between algorithms, no significant difference in lesion detection was observed within dose levels. Detection of 233 lesions ≤ 10 mm was deteriorated with lower dose levels despite DLR denoising, with 185 detected at standard-dose IR (79.4%; 95% CI: 73.5–84.3) vs 128 at medium-dose DLR (54.9%; 95% CI: 48.3–61.4; p  < 0.001) and 105 at low-dose DLR (45.1%; 95% CI: 38.6–51.7; p  < 0.001). Conclusion Diagnostic performance for liver lesion detection was comparable between algorithms. When the detection of smaller lesions is important, DLR did not facilitate substantial dose reduction. Key Points Question Methods to reduce CT radiation dose are desirable in clinical practice, and DLR has shown promising image denoising capabilities . Findings Liver lesion detection was comparable for DLR and IR across dose levels, but detection of smaller lesions deteriorated with lower dose levels . Clinical relevance Although potent in image noise reduction, the diagnostic performance of DLR is comparable to IR at standard-dose and reduced-dose CT. Care must be taken in pursuit of dose reduction when the detection and characterization of smaller liver lesions are of clinical importance . Graphical Abstract

• Øhrn, Frank-David; Engseth, Lars; Pripp, Are Hugo; Schulz, Anselm & Röhrl, Stephan Maximilian (2025). Precision of computer tomography based RSA on femoral implants in total knee arthroplasty: A porcine cadaver study. Clinical Biomechanics. ISSN 0268-0033. 123, s. 1–4. doi: 10.1016/j.clinbiomech.2025.106456. Fulltekst i vitenarkiv Vis sammendrag

  Background: Radiostereometric analysis is the gold standard for assessing migration of orthopaedic implants. The novel CT-based radiostereometric analysis yields high precision of evaluation of tibial implants. We analyzed the precision of CT-based radiostereometric analysis on femoral implants in knee arthroplasty at different dose levels, and compared it to previously published results on tibial implants and the available literature on precision of radiostereometric analysis. Methods: We performed a total knee arthroplasty on a porcine cadaver knee. In the subsequent 7 CT scans, we analyzed the precision of the CT-based radiostereometric analysis method in 21 samples at two different effective doses (standard and low dose), and compared this to literature on radiostereometric analysis. Findings: CT-based radiostereometric analysis of maximum total point motion of femoral and tibial components showed a precision difference of (mean, 95 % confidence interval) 0.18 mm (0.13 to 0.22), P < 0.001. For femoral implants (mean, 95 % confidence interval, standard deviation) we found precisions of 0.25 mm (0.21-0.29, 0.1) and 0.29 (0.25-0.32, 0.08) mm for the standard and low dose protocols respectively. Variability ratios of tibia versus femur and standard versus low dose femur (95 % confidence interval) were 18.3 (7.4-45.1) and 0.7 (0.3-1.7) with respective P-values of <0.001 and 0.40. Interpretation: CT-based radiostereometric analysis on femoral implants in total knee arthroplasty is feasible and has a lower, yet still acceptable, precision compared to CT-based radiostereometric analysis on tibial implants in a porcine cadaver. However, confirmation in clinical studies is warranted.

• Engseth, Lars; Øhrn, Frank-David; Schulz, Anselm & Röhrl, Stephan Maximilian (2025). CT-based migration analysis of a tibial component compared to radiostereometric analysis : one-year results of a prospective single-group implant safety study. The Bone & Joint Journal. ISSN 2049-4394. 107-B(2), s. 173–180. doi: 10.1302/0301-620X.107B2.BJJ-2024-0356.R2. Fulltekst i vitenarkiv Vis sammendrag

  Aims Radiostereometric analysis (RSA) is considered the gold standard for in vivo migration analysis, but CT-based alternatives show comparable results in the shoulder and hip. We have previously validated a CT-based migration analysis method (CTMA) in a knee phantom compared to RSA. In this study, we validated the method in patients undergoing total knee arthroplasty (TKA). Our primary outcome measure was the difference in maximum total point motion (MTPM) between the differing methods. Methods A total of 31 patients were prospectively studied having undergone an uncemented medial pivot knee TKA. Migrations were measured up to 12 months with marker-based and model-based RSA, and CT-RSA. Results Mean precision data for MTPM were 0.27 mm (SD 0.09) for marker-based RSA, 0.37 mm (SD 0.26) for model-based RSA, and 0.25 mm (SD 0.11) for CTMA. CTMA was as precise as both RSA methods (p = 0.845 and p = 0.156). At three months, MTPM showed a mean of 0.66 mm (95% CI 0.52 to 0.81) for marker-based RSA, 0.79 (95% CI 0.64 to 0.94) for model-based RSA, and 0.59 (95% CI 0.47 to 0.72) for CTMA. There was no difference between CTMA and marker-based RSA (p = 0.400), but CTMA showed lower migration than model-based RSA (p = 0.019). At 12 months, MTPM was 1.03 (95% CI 0.79 to 1.26) for marker-based RSA, 1.02 (95% CI 0.79 to 1.25) for model-based RSA, and 0.71 (95% CI 0.48 to 0.94) for CTMA. MTPM for CTMA was lower than both RSA methods (p < 0.001). Differences between migration increased between the methods from three to 12 months. Mean effective radiation doses per examination were 0.016 mSv (RSA) and 0.069 mSv (CT). Imaging time for performing RSA radiographs was 17 minutes 26 seconds (SD 7 mins 9 sec) and 4 minutes 24 seconds (SD 2 mins 3 sec) for CT. Conclusion No difference in precision was found between CTMA and marker- or model-based RSA, but CTMA shows lower migration values of the tibial component at 12 months. CTMA can be used with low effective radiation doses, and CT image acquisition is faster to perform than RSA methods and may be suitable for use in ordinary clinical settings.

• Viktil, Ellen; Hanekamp, Bettina; Nesbakken, Arild; Løberg, Else Marit; Sjo, Ole Helmer & Negård, Anne [Vis alle 8 forfattere av denne artikkelen] (2024). Early rectal cancer: The diagnostic performance of MRI supplemented with a rectal micro-enema and a modified staging system to identify tumors eligible for local excision. Acta Radiologica Open. 13(5). doi: 10.1177/20584601241241523. Fulltekst i vitenarkiv Vis sammendrag

  Background In staging early rectal cancers (ERC), submucosal tumor depth is one of the most important features determining the possibility of local excision (LE). The micro-enema (Bisacodyl) induces submucosal edema and may hypothetically improve the visualization of tumor depth. Purpose To test the diagnostic performance of MRI to identify ERC suitable for LE when adding a pre-procedural micro-enema and concurrent use of a modified classification system. Material and Methods In this prospective study, we consecutively included 73 patients with newly diagnosed rectal tumors. Two experienced radiologists independently interpreted the MRI examinations, and diagnostic performance was calculated for local tumors eligible for LE (Tis-T1sm2, n = 43) and non-local tumors too advanced for LE (T1sm3-T3b, n = 30). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were registered for each reader. Inter- and intra-reader agreements were assessed by kappa statistics. Lymph node status was derived from the clinical MRI reports. Results Reader1/reader2 achieved sensitivities of 93%/86%, specificities of 90%/83%, PPV of 93%/88%, and NPV of 90%/81%, respectively, for identifying tumors eligible for LE. Rates of overstaging of local tumors were 7% and 14% for the two readers, and kappa values for the inter- and intra-reader agreement were 0.69 and 0.80, respectively. For tumors ≤T2, all metastatic lymph nodes were smaller than 3 mm on histopathology. Conclusion MRI after a rectal micro-enema and concurrent use of a modified staging system achieved good diagnostic performance to identify tumors suitable for LE. The rate of overstaging of local tumors was comparable to results reported in previous endorectal ultrasound (ERUS) studies.

• Røhme, Linn Andrea Gjerberg; Homme, Tora Fjeld; Johansen, Cathrine Kiperberg; Schulz, Anselm; Aaløkken, Trond Mogens & Johansson, Ellen [Vis alle 11 forfattere av denne artikkelen] (2024). Image quality and radiation doses in abdominal CT: A multicenter study. European Journal of Radiology. ISSN 0720-048X. 178. doi: 10.1016/j.ejrad.2024.111642. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: To benchmark image quality and corresponding radiation doses for acute abdominal CT examination across different laboratories and CT manufacturers. Method: An anthropomorphic phantom was scanned once with local abdominal CT protocols at 40 CT scanners, from four vendors, in thirty-three sites. Quantitative image quality was evaluated by CNR and SNR in the liver and kidney parenchyma. Qualitative image quality was assessed by visual grading analysis performed by three experienced radiologists using a five-point Likert scale to score thirteen image quality criteria. The CTDIvol was recorded for each scan. Pearson’s correlation coefficient was calculated for the continuous variables, and the intraclass correlation coefficient was used to investigate interrater reliability between the radiologists. Results: CTDIvol ranged from 3.5 to 12 mGy (median 5.3 mGy, third quartile 6.7 mGy). SNR in liver parenchyma ranged from 4.4 to 14.4 (median 8.5), and CNR ranged from 2.7 to 11.2 (median 6.1). A weak correlation was found between CTDIvol and CNR (r = 0.270, p = 0.092). Variations in CNR across scanners at the same dose level CTDIvol were observed. No significant difference in CTDIvol or CNR was found based on scanner installation year. The oldest scanners had a 15 % higher median CTDIvol and a 12 % lower median CNR. The ICC showed acceptable agreement for all dose groups: low (ICC=0.889), medium (ICC=0.767), high (ICC=0.847), and in low (ICC=0.803) and medium (ICC=0.811) CNR groups. Conclusion: There was large variation in radiation dose and image quality across the different CT scanners. Interestingly, the weak correlation between CTDIvol and CNR indicates that higher doses do not consistently improve CNR, indicating a need for systematic assessment and optimization of image quality and radiation doses for the abdominal CT examination

• Viktil, Ellen; Hanekamp, Bettina; Nesbakken, Arild; Løberg, Else Marit; Sjo, Ole Helmer & Negård, Anne [Vis alle 8 forfattere av denne artikkelen] (2024). MRI of early rectal cancer; bisacodyl micro-enema increases submucosal width, reader confidence, and tumor conspicuity. Abdominal Radiology. ISSN 2366-004X. 00(0), s. 1–13. doi: 10.1007/s00261-024-04701-1. Fulltekst i vitenarkiv Vis sammendrag

  Purpose To investigate the influence of a micro-enema on diagnostic performance, submucosal width, reader confidence, and tumor conspicuity using MRI to stage early rectal cancers (ERC). Methods In this single-center study, we consecutively included 50 participants with assumed ERC who all completed MRI with (MRin) and without (MRex) a micro-enema. The diagnostic performance was recorded for two experienced radiologists using histopathology as the gold standard. In addition, the width of the submucosa in the tumor-bearing wall, reader confidence for T-staging, and tumor conspicuity were assessed. Significance levels were calculated using McNemar’s test (diagnostic performance) and Wilcoxon’s signed-rank test (reader confidence, submucosal width, and conspicuity). Interreader agreement was assessed using kappa statistics. Results Sensitivity/specificity were for Reader1 91%/87% for both MRex and MRin and for Reader2 74%/87% and 89%/87%, both readers p > 0.05. The micro-enema induced a significant widening of the submucosa, p < 0.001, with a mean increase of 2.2/2.8 mm measured by Reader1/Reader2. Reader confidence in T-staging and tumor conspicuity increased for both readers, p < 0.005. The proportion of tumors with both correct staging and high reader confidence increased from 58% (29/50) to 80% (40/50) (p = 0.04) for Reader1 and from 42% (21/50) to 72% (36/50) (p = 0.002) for Reader2. Interreader agreement increased from moderate (kappa 0.58) to good (kappa 0.68). Conclusion The micro-enema significantly increased the submucosal width in the tumor-bearing wall, reader confidence, and tumor conspicuity and improved interreader agreement from moderate to good. Sensitivity and specificity in T-staging did not improve, but there was a significant increase in the proportion of tumors staged with both high confidence and correct T-stage.

• Stern, Nadide Mutlukoca; Mikalsen, Lars Tore Gyland; Dueland, Svein; Schulz, Anselm; Line, Pål Dag & Stokke, Caroline [Vis alle 7 forfattere av denne artikkelen] (2024). The prognostic value of [18F]FDG PET/CT texture analysis prior to transplantation for unresectable colorectal liver metastases. Clinical Physiology and Functional Imaging. ISSN 1475-0961. 45(1). doi: 10.1111/cpf.12908. Fulltekst i vitenarkiv Vis sammendrag

  Introduction To determine whether heterogeneity in colorectal liver metastases (CRLM) 18F fluorodeoxyglucose [18F]FDG distribution is predictive of disease-free survival (DFS) and overall survival (OS) following liver transplantation (LT) for unresectable CRLM. Methods The preoperative [18F]FDG positron emission tomography/computed tomography examinations of all patients in the secondary cancer 1 and 2 studies were retrospectively assessed. Maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), and six texture heterogeneity parameters (joint entropyGLCM, dissimilarityGLCM, grey level varianceSZM, size zone varianceSZM, and zone percentageSZM, and morphological feature convex deficiency) were obtained. DFS and OS for patients over and under the median value for each of these parameters were compared by using the Kaplan Meier method and log rank test. Results Twenty-eight out of 40 patients who underwent LT for unresectable CRLM had liver metastases with uptake above liver background and were eligible for inclusion. Low MTV (p < 0.001) and dissimilarityGLCM (p = 0.016) were correlated to longer DFS. Low MTV (p < 0.001) and low values of the texture parameters dissimilarityGLCM (p = 0.038), joint entropyGLCM (p = 0.015) and zone percentageSZM (p = 0.037) were significantly correlated to longer OS. SUVmax was not correlated to DFS and OS. Conclusion Although some texture parameters were able to significantly predict DFS and OS, MTV seems to be superior to predict both DFS and OS following LT for unresectable CRLM.

• Varghese, Bino Abel; Cen, Steven Yong; Jensen, Kristin; Levy, Joshua; Andersen, Hilde Kjernlie & Schulz, Anselm [Vis alle 9 forfattere av denne artikkelen] (2024). Technical and clinical considerations of a physical liver phantom for CT radiomics analysis. Journal of Applied Clinical Medical Physics. 25(4). doi: 10.1002/acm2.14309. Fulltekst i vitenarkiv
• Hanekamp, Bettina; Virdee, Pradeep S.; Goh, Vicky; Jones, Michael; Hansen, Rasmus Hvass & Johannesen, Helle Hjorth [Vis alle 10 forfattere av denne artikkelen] (2024). Diffusion-weighted magnetic resonance imaging as an early prognostic marker of chemoradiotherapy response in squamous cell carcinoma of the anus: An individual patient data meta-analysis. Physics and imaging in radiation oncology (PIRO). 31. doi: 10.1016/j.phro.2024.100618. Fulltekst i vitenarkiv
• Varghese, Bino Abel; Cen, Steven Yong; Jensen, Kristin; Levy, Joshua; Andersen, Hilde Kjernlie & Schulz, Anselm [Vis alle 9 forfattere av denne artikkelen] (2023). Investigating the role of imaging factors in the variability of CT-based texture analysis metrics. Journal of Applied Clinical Medical Physics. doi: 10.1002/acm2.14192. Fulltekst i vitenarkiv
• Øhrn, Frank-David; Engseth, Lars; Pripp, Are Hugo; Röhrl, Stephan Maximilian & Schulz, Anselm (2023). Dose reduction does not impact the precision of CT-based RSA in tibial implants: a diagnostic accuracy study on precision in a porcine cadaver. Acta Orthopaedica. ISSN 1745-3674. 94, s. 550–554. doi: 10.2340/17453674.2023.24022. Fulltekst i vitenarkiv Vis sammendrag

  Background and purpose: Radiostereometric analysis (RSA) is the gold standard for evaluation of migration of implants. CT-RSA has been shown to have precision at the level of RSA in hip, shoulder, and knee joint replacements. We aimed to assess the impact of dose reduction on precision of CT-RSA on tibial implants, comparing it with previously published data on precision of standard dose CT-RSA on tibial implants. Material and methods: We performed a total knee arthroplasty on a porcine knee cadaver, and subsequent CT-RSA with low effective doses (0.02 mSv). We compared the results with previously published CT-RSA data with standard (0.08 mSv) dose. The primary outcome variable was the difference in precision of the maximum total translation (MTT). Secondary variables included ratios of variances and standard deviations, and precision of peripheral point translations, center-of-mass translations, and rotations. A difference of more than 0.1 mm in precision was defined as clinically relevant. Our hypothesis was that precisions of low and standard CT-RSA doses were equal. Results: Low dose (mean 0.07, 95% confidence interval [CI] 0.06–0.08) and standard dose CT-RSA (0.08, CI 0.07–0.09) achieve similar precision, with difference in precision of MTT of 0.01, CI 0.00–0.02 mm. The F-statistic (0.99, CI 0.63–1.55) and sdtest (1.05, CI 0.43–2.58) also supported this. Conclusion: We conclude that the precision of low dose CT-RSA for tibial implants on a porcine cadaver is equal to standard dose CT-RSA. However, these findings should be confirmed in clinical trials.

• Njølstad, Tormund Salvesen; Schulz, Anselm; Jensen, Kristin; Andersen, Hilde Kjernlie & Martinsen, Anne Catrine Trægde (2023). Improved image quality with deep learning reconstruction – a study on a semi-anthropomorphic upper-abdomen phantom. Research in Diagnostic and Interventional Imaging (ReDII). 5(March). doi: 10.1016/j.redii.2023.100022. Fulltekst i vitenarkiv
• Hanekamp, Bettina; Viktil, Ellen; Slørdahl, Kathinka; Dormagen, Johann Baptist; Kløw, Nils-Einar & Malinen, Eirik [Vis alle 9 forfattere av denne artikkelen] (2023). Magnetic resonance imaging of anal cancer: tumor characteristics and early prediction of treatment outcome. Strahlentherapie und Onkologie (Print). ISSN 0179-7158. s. 1–9. doi: 10.1007/s00066-023-02114-5. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Purpose To analyze tumor characteristics derived from pelvic magnetic resonance imaging (MRI) of patients with squamous cell carcinoma of the anus (SCCA) before and during chemoradiotherapy (CRT), and to compare the changes in these characteristics between scans of responders vs. nonresponders to CRT. Methods We included 52 patients with a pelvic 3T MRI scan prior to CRT (baseline scan); 39 of these patients received an additional scan during week 2 of CRT (second scan). Volume, diameter, extramural tumor depth (EMTD), and external anal sphincter infiltration (EASI) of the tumor were assessed. Mean, kurtosis, skewness, standard deviation (SD), and entropy values were extracted from apparent diffusion coefficient (ADC) histograms. The main outcome was locoregional treatment failure. Correlations were evaluated with Wilcoxon’s signed rank-sum test and Pearson’s correlation coefficient, quantile regression, univariate logistic regression, and area under the ROC curve (AUC) analyses. Results In isolated analyses of the baseline and second MRI scans, none of the characteristics were associated with outcome. Comparison between the scans showed significant changes in several characteristics: volume, diameter, EMTD, and ADC skewness decreased in the second scan, although the mean ADC increased. Small decreases in volume and diameter were associated with treatment failure, and these variables had the highest AUC values (0.73 and 0.76, respectively) among the analyzed characteristics. Conclusion Changes in tumor volume and diameter in an early scan during CRT could represent easily assessable imaging-based biomarkers to eliminate the need for analysis of more complex MRI characteristics.

• Engseth, Lars; Grønsund, Jørgen; Aunan, Eirik; Brattgjerd, Jan Egil; Schulz, Anselm & Moatshe, Gilbert [Vis alle 7 forfattere av denne artikkelen] (2023). A novel instrument for ligament balancing: a biomechanical study in human cadaveric knees. Journal of Experimental Orthopaedics. 10(1). doi: 10.1186/s40634-023-00643-7. Fulltekst i vitenarkiv Vis sammendrag

  Purpose: Ligament balancing is a prerequisite for good function and survival in total knee arthroplasty (TKA). Various balancing techniques exist, but none have shown superior results. The pie-crusting technique by Bellemans of the medial collateral ligament is commonly utilized; however, it can be difficult to achieve repeatable ligament lengthening with this technique. Therefore, we invented a novel instrument to standardize the pie-crusting technique of the superficial and deep medial collateral ligament (hereafter MCL). The purpose was to examine if pie-crusting with the instrument could produce repeatable ligament lengthening. Methods: The MCL was isolated in 16 human cadaveric knees, and subjected to axial tension. The instrument was composed of a specific grid of holes in rows, used to guide sequential pie-crusting puncturing of the MCL with a Ø1.6 mm end-cutting cannula. Ligament lengthening was measured after each row of punctures. Regression analysis was performed on the results. Results: Mean lengthening ± SD in human cadaveric MCL for puncturing of row 1 in the instrument was 0.06 ± 0.09 mm, 0.06 ± 0.04 mm for row 2, 0.09 ± 0.08 mm for row 3, 0.06 ± 0.05 mm for row 4 and 0.06 ± 0.04 mm for row 5, giving a mean total lengthening of 0.33 ± 0.20 mm. Linear regression revealed that MCLs were repeatably lengthened by 0.07 mm per row when punctured using the instrument. Conclusions: MCLs showed linear lengthening in human cadavers for subsequent use of the instrument. Our instrument shows promising results for repeatable ligament lengthening.

• Evensen, Helge; Sandstad, Olav; Larssen, Lene; Hagen, Milada; Kristensen, Vendel Ailin & Søvik, Torgeir Thorson [Vis alle 9 forfattere av denne artikkelen] (2023). Intraoperative distensibility measurement in POEM for achalasia: impact on patient outcome and associations with other outcome variables at 1-year follow-up. Surgical Endoscopy. ISSN 0930-2794. 37, s. 9283–9290. doi: 10.1007/s00464-023-10494-z. Fulltekst i vitenarkiv Vis sammendrag

  Background and aims The functional luminal imaging probe (FLIP) can provide measurements of lower esophageal sphincter (LES) distensibility. Studies report that use of intraoperative FLIP examination during peroral endoscopic myotomy (POEM) for achalasia is associated with treatment success, but evidence is limited and inconsistent. The main aim of the present study was to assess associations between intraoperative FLIP values and 1-year outcomes. Additionally, associations between 1-year FLIP measurements and other 1-year outcome variables were studied. Methods We performed a single-center prospective study of consecutive achalasia patients treated with POEM with a standardized 1-year follow-up. The inclusion period was from June 2017 to January 2020. We compared 1-year outcomes (FLIP measurement values, Eckardt score (ES), reflux esophagitis, timed barium esophagogram (TBE), and lower esopha- geal sphincter resting pressure (LES-rp)) in patients with and without intraoperative FLIP examination. We also assessed associations between intraoperative FLIP values, 1-year FLIP values, and other 1-year outcomes. Results are given as median (IQR), and non-parametrical statistical analyses were applied. Results Sixty-two patients (27 females) with median age 45 years (35–54) were included. Baseline characteristics were similar in patients with (n = 32) and without (n = 30) intraoperative FLIP examination. In patients with intraoperative FLIP, ES was 2 (1–3) and LES distensibility index (DI) 3.7 (2.6–5.4) after 1 year, compared with ES 2 (1–3) and DI 4.0 (3.1–6.8)) in patients without intraoperative FLIP (ns). Intraoperative DI was not correlated with 1-year ES or DI. One-year DI cor- related significantly with 1-year ES (rs − 0.42), TBE (rs − 0.34), and LES-rp (rs − 0.29). Conclusions Use of intraoperative FLIP measurements in POEM for achalasia is not associated with improved 1-year out- come, and the clinical value of intraoperative FLIP in POEM for achalasia is questioned. Follow-up FLIP measurements are moderately associated with symptomatic outcome, and may serve as an additional diagnostic modality in post-treatment evaluation.

• Engseth, Lars; Schulz, Anselm; Pripp, Are Hugo; Röhrl, Stephan Maximilian & Øhrn, Frank-David (2023). CT-based migration analysis is more precise than radio-stereometric analysis for tibial implants: a phantom study on a porcine cadaver. Acta Orthopaedica. ISSN 1745-3674. 94, s. 207–214. doi: 10.2340/17453674.2023.12306. Fulltekst i vitenarkiv Vis sammendrag

  Background and purpose: Radiostereometric analysis (RSA) is the gold standard for migration analysis, but computed tomography analysis methods (CTRSA) have shown comparable results in other joints. We attempted to validate precision for CT compared with RSA for a tibial implant. Material and methods: RSA and CT were performed on a porcine knee with a tibial implant. Marker-based RSA, model-based RSA (MBRSA), and CT scans from 2 different manufacturers were compared. CT analysis was performed by 2 raters for reliability evaluation. Results: 21 double examinations for precision measurements for RSA and CT-based Micromotion Analysis (CTMA) were analysed. Mean (95% confidence interval) precision data for maximum total point motion (MTPM) using marker-based RSA was 0.45 (0.19–0.70) and 0.58 (0.20–0.96) using MBRSA (F-statistic 0.44 [95% CI 0.18–1.1], p = 0.07). Precision data for total translation (TT) for CTMA was 0.08 (0.03–0.12) for the GE scanner and 0.11 (0.04–0.19) for the Siemens scanner (F-statistic 0.37 [0.15–0.91], p = 0.03). When comparing the aforementioned precision for both RSA methods with both CTMA analyses, CTMA was more precise (p < 0.001). The same pattern was seen for other translations and migrations. Mean effective radiation doses were 0.005 mSv (RSA) (0.0048–0.0050) and 0.08 mSv (CT) (0.078–0.080) (p < 0.001). Intra- and interrater reliability were 0.79 (0.75–0.82) and 0.77 (0.72–0.82), respectively. Conclusion: CTMA is more precise than RSA for migration analysis of a tibial implant, has overall good intra- and interrater reliability but higher effective radiation doses in a porcine cadaver.

• Njølstad, Tormund Salvesen; Jensen, Kristin; Dybwad, Anniken; Salvesen, Øyvind Olav; Andersen, Hilde Kjernlie & Schulz, Anselm (2022). Low-contrast detectability and potential for radiation dose reduction using deep learning image reconstruction-A 20-reader study on a semi-anthropomorphic liver phantom. European Journal of Radiology Open (EJR Open). 9. doi: 10.1016/j.ejro.2022.100418. Fulltekst i vitenarkiv Vis sammendrag

  Background A novel deep learning image reconstruction (DLIR) algorithm for CT has recently been clinically approved. Purpose To assess low-contrast detectability and dose reduction potential for CT images reconstructed with the DLIR algorithm and compare with filtered back projection (FBP) and hybrid iterative reconstruction (IR). Material and methods A customized upper-abdomen phantom containing four cylindrical liver inserts with low-contrast lesions was scanned at CT dose indexes of 5, 10, 15, 20 and 25 mGy. Images were reconstructed with FBP, 50% hybrid IR (IR50), and DLIR of low strength (DLL), medium strength (DLM) and high strength (DLH). Detectability was assessed by 20 independent readers using a two-alternative forced choice approach. Dose reduction potential was estimated separately for each strength of DLIR using a fitted model, with the detectability performance of FBP and IR50 as reference. Results For the investigated dose levels of 5 and 10 mGy, DLM improved detectability compared to FBP by 5.8 and 6.9 percentage points (p.p.), and DLH improved detectability by 9.6 and 12.3 p.p., respectively (all p < .007). With IR50 as reference, DLH improved detectability by 5.2 and 9.8 p.p. for the 5 and 10 mGy dose level, respectively (p < .03). With respect to this low-contrast detectability task, average dose reduction potential relative to FBP was estimated to 39% for DLM and 55% for DLH. Relative to IR50, average dose reduction potential was estimated to 21% for DLM and 42% for DLH. Conclusions: Low-contrast detectability performance is improved when applying a DLIR algorithm, with potential for radiation dose reduction.

• Njølstad, Tormund Salvesen; Schulz, Anselm; Godt, Johannes Jakob C; Brøgger, Helga Maria; Johansen, Cathrine Kiperberg & Andersen, Hilde Kjernlie [Vis alle 7 forfattere av denne artikkelen] (2021). Improved image quality in abdominal computed tomography reconstructed with a novel Deep Learning Image Reconstruction technique - initial clinical experience. Acta Radiologica Open. 10(4), s. 1–9. doi: 10.1177/20584601211008391. Fulltekst i vitenarkiv
• Grut, Harald; Line, Pål Dag; Labori, Knut Jørgen; Schulz, Anselm & Dueland, Svein (2021). Survival after liver resection and liver transplantation for colorectal liver metastases: a comparative analysis stratified by metabolic tumor volume assessed by 18F-FDG PET/CT. HPB. ISSN 1365-182X. doi: 10.1016/j.hpb.2021.11.015. Fulltekst i vitenarkiv
• Evensen, Helge; Småstuen, Milada Cvancarova; Schulz, Anselm; Kristensen, Vendel Ailin; Larssen, Lene & Skattum, Jorunn Pettersen [Vis alle 9 forfattere av denne artikkelen] (2021). One year comprehensive prospective follow-up of achalasia patients after peroral endoscopic myotomy. Annals of Medicine. ISSN 0785-3890. 53(1), s. 2227–2235. doi: 10.1080/07853890.2021.2005253. Fulltekst i vitenarkiv Vis sammendrag

  Peroral endoscopic myotomy (POEM) is an established therapy for achalasia, but outcome evaluation has often been limited to Eckardt score (ES). The present study was aimed to improve knowledge about outcome evaluation and predictive outcome factors by performing a comprehensive objective evaluation of achalasia patients treated by POEM. Methods: This single centre prospective study reports outcome data 12 months after POEM in treatment-naive achalasia patients. A predefined follow-up protocol included ES, high resolution manometry, 24-h pH measurement, upper endoscopy and timed barium esophagogram (TBE). Univariate and multivariate regression analyses were performed to analyze association between post-POEM variables and identify predictive factors for objective outcome. Results: Fifty patients were included with a drop-out rate of < .001), and 28% (13/47) of the patients had a positive 24-h pH registration. An oesophageal diameter >3 cm after POEM was associated with treatment failure assessed by ES (p ¼ .04) and TBE (p ¼ .03). Advanced achalasia stage (p ¼ .02) and long symptom duration (p ¼ .04) were identified as independent predictive factors for poor outcome assessed by TBE. Conclusions: The present study confirms that POEM is an efficient therapy for achalasia. The comprehensive objective evaluation after POEM demonstrates that long symptom duration and major changes in oesophageal anatomy at diagnosis imply poor treatment outcome, and a post-POEM dilated oesophagus is associated with treatment failure.

• Njølstad, Tormund Salvesen; Young, Victoria Solveig; Drolsum, Anders; Dormagen, Johann Baptist; Hofstad, Bjørn & Schulz, Anselm (2021). Is there need for routine CT colonography after CT-verified uncomplicated diverticulitis of the sigmoid colon? European Journal of Radiology Open (EJR Open). 8. doi: 10.1016/j.ejro.2021.100341. Fulltekst i vitenarkiv
• Godt, Johannes Jakob Clemens; Johansen, Cathrine K.; Martinsen, Anne Catrine Trægde; Schulz, Anselm; Brøgger, Helga Maria & Jensen, Kristin [Vis alle 8 forfattere av denne artikkelen] (2021). Iterative reconstruction improves image quality and reduces radiation dose in trauma protocols; A human cadaver study. Acta Radiologica Open. 10(10), s. 1–11. doi: 10.1177/20584601211055389. Fulltekst i vitenarkiv Vis sammendrag

  Background: Radiation-related cancer risk is an object of concern in CT of trauma patients, as these represent a young population. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers. Purpose: To compare image quality in human cadaver exposed to thoracoabdominal computed tomography using IR and standard filtered back-projection (FBP) at different dose levels. Material and methods: Ten cadavers were scanned at full dose and a dose reduction in CTDIvol of 5 mGy (low dose 1) and 7.5 mGy (low dose 2) on a Siemens Definition Flash 128-slice computed tomography scanner. Low dose images were reconstructed with FBP and Sinogram affirmed iterative reconstruction (SAFIRE) level 2 and 4. Quantitative image quality was analyzed by comparison of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Qualitative image quality was evaluated by use of visual grading regression (VGR) by four radiologists. Results: Readers preferred SAFIRE reconstructed images over FBP at a dose reduction of 40% (low dose 1) and 56% (low dose 2), with significant difference in overall impression of image quality. CNR and SNR showed significant improvement for images reconstructed with SAFIRE 2 and 4 compared to FBP at both low dose levels. Conclusions: Iterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population.

• Godt, Johannes Jakob C; Eken, Torsten; Schulz, Anselm; Øye, Kjetil; Hagen, Thijs & Dormagen, Johann Baptist (2020). Do we really need the arterial phase on CT in pelvic trauma patients? Emergency Radiology. ISSN 1070-3004. 28, s. 37–46. doi: 10.1007/s10140-020-01820-2. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Purpose To evaluate whether an arterial phase scan improves the diagnostic performance of computed tomography to identify pelvic trauma patients who received angiographic intervention on demand of the trauma surgeon. Methods This retrospective single-center study was performed at an academic Scandinavian trauma center with approximately 2000 trauma admissions annually. Pelvic trauma patients with arterial and portal venous phase CT from 2009 to 2015 were included. The patients were identified from the institutional trauma registry. Images were interpreted by two radiologists with more than 10 years of trauma radiology experience. Positive findings for extravasation on portal venous phase alone or on both arterial and portal venous phase were compared, with angiographic intervention as clinical outcome. Results One hundred fifty-seven patients (54 females, 103 males) with a median age of 45 years were enrolled. Sixteen patients received angiographic intervention. Positive CT findings on portal venous phase only had a sensitivity and specificity of 62% and 86%, vs. 56% and 93% for simultaneous findings on arterial and portal venous phase. Specificity was significantly higher for positive findings in both phases compared with portal venous phase only. Applying a threshold &gt; 0.9 cm of extravasation diameter to portal venous phase only resulted in sensitivity and specificity identical to those of both phases. Conclusion Arterial phase scan in addition to portal venous phase scan did not improve patient selection for angiography. Portal venous phase extravasation size alone may be used as an imaging-based biomarker of the need for angiographic intervention.

• Grut, Harald; Stern, Nadide; Dueland, Svein; Labori, Knut Jørgen; Dormagen, Johann Baptist & Schulz, Anselm (2020). Preoperative Preoperative 18F-FDG PET/computed tomography predicts survival following resection for colorectal liver metastases. Nuclear medicine communications. ISSN 0143-3636. 41(9), s. 916–923. doi: 10.1097/MNM.0000000000001235. Fulltekst i vitenarkiv
• Schulz, Anselm; Joelsen-Hatlehol, Eivind Selstø; Brudvik, Kristoffer Watten; Aasand, Kjersti Karoline; Hanekamp, Bettina & Viktil, Ellen [Vis alle 8 forfattere av denne artikkelen] (2019). Preoperative detection of colorectal liver metastases: DWI alone or combined with MDCT is no substitute for Gd-EOB-DTPA-enhanced MRI. Acta Radiologica Open. s. 1–10. doi: 10.1177/0284185119864000. Fulltekst i vitenarkiv
• Godt, Johannes Jakob C; Eken, Torsten; Schulz, Anselm; Johansen, Cathrine Kiperberg; Aarsnes, Anette & Dormagen, Johann Baptist (2018). Triple-split-bolus versus single-bolus CT in abdominal trauma patients: a comparative study. Acta Radiologica. ISSN 0284-1851. 59(9), s. 1038–1044. doi: 10.1177/0284185117752522. Fulltekst i vitenarkiv
• Skogen, Karoline; Schulz, Anselm; Helseth, Eirik; Ganeshan, Balaji; Dormagen, Johann Baptist & Server, Andrés (2018). Texture analysis on diffusion tensor imaging: discriminating glioblastoma from single brain metastasis. Acta Radiologica. ISSN 0284-1851. s. 1–11. doi: 10.1177/0284185118780889. Fulltekst i vitenarkiv
• Skogen, Karoline; Schulz, Anselm; Dormagen, Johann Baptist; Ganeshan, Balaji; Helseth, Eirik & SERVER, ANDRES (2016). Diagnostic performance of texture analysis on MRI in grading cerebral gliomas. European Journal of Radiology. ISSN 0720-048X. 85(4), s. 824–829. doi: 10.1016/j.ejrad.2016.01.013. Fulltekst i vitenarkiv
• Schulz, Anselm; Viktil, Ellen; Godt, Johannes Jakob C; Johansen, Cathrine Kiperberg; Dormagen, Johann Baptist & Holtedahl, Jon Erik [Vis alle 9 forfattere av denne artikkelen] (2016). Diagnostic performance of CT, MRI and PET/CT in patients with suspected colorectal liver metastases: The superiority of MRI. Acta Radiologica. ISSN 0284-1851. 57(9), s. 1040–1048. doi: 10.1177/0284185115617349. Fulltekst i vitenarkiv
• Schulz, Anselm; Godt, Johannes Jakob C; Dormagen, Johann Baptist; Holtedahl, Jon Erik; Bogsrud, Trond & Labori, Knut Jørgen [Vis alle 8 forfattere av denne artikkelen] (2015). Respiratory gated PET/CT of the liver: A novel method and its impact on the detection of colorectal liver metastases. European Journal of Radiology. ISSN 0720-048X. 84(8), s. 1424–1431. doi: 10.1016/j.ejrad.2015.05.011. Fulltekst i vitenarkiv
• Labori, Knut Jørgen; Schulz, Anselm; Drolsum, Anders; Guren, Marianne; Kløw, Nils-Einar & Bjørnbeth, Bjørn Atle (2015). Radiofrequency ablation of unresectable colorectal liver metastases: trends in management and outcome during a decade at a single center. Acta Radiologica Open. 4(7), s. 1–9. doi: 10.1177/2058460115580877. Fulltekst i vitenarkiv
• Schulz, Anselm; Dormagen, Johann Baptist; Drolsum, Anders; Bjørnbeth, Bjørn Atle; Labori, Knut Jørgen & Klow, Nils-Einar (2012). Impact of contrast-enhanced intraoperative ultrasound on operation strategy in case of colorectal liver metastasis. Acta Radiologica. ISSN 0284-1851. 53(10), s. 1081–1087. doi: 10.1258/ar.2012.120049. Fulltekst i vitenarkiv

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• Grønsund, Jørgen; Aunan, Eirik; Brattgjerd, Jan Egil; Schulz, Anselm; Moatshe, Gilbert & Röhrl, Stephan Maximilian Herbert (2022). A novel instrument for ligament balancing in Total Knee Arthroplasty – a biomechanical study in porcine tissue. Fulltekst i vitenarkiv
• Aunan, Eirik; Schulz, Anselm; Moatshe, Gilbert; Brattgjerd, Jan Egil; Grønsund, Jørgen & Röhrl, Stephan Maximilian Herbert (2022). A novel instrument for ligament balancing in Total Knee Arthroplasty – a biomechanical study in porcine and human tissue. Fulltekst i vitenarkiv
• Pripp, Are Hugo; Schulz, Anselm; Röhrl, Stephan Maximilian Herbert & Øhrn, Frank-David (2022). Presisjon av et nytt CT-basert analyseprogram sammenlignet med radiostereometrisk analyse – en fantomstudie på gris. Fulltekst i vitenarkiv
• Schulz, Anselm (2013). Response to "Contrast-enhanced intraoperative ultrasound". Acta Radiologica. ISSN 0284-1851. 54(5), s. 533–533. doi: 10.1177/0284185113485679. Fulltekst i vitenarkiv
• Viktil, Ellen & Schulz, Anselm (2026). Improving diagnostic accuracy of MRI in early rectal cancer: the effects of a bisacodyl micro-enema. Universitetet i Oslo. ISSN 9788234808883. Fulltekst i vitenarkiv Vis sammendrag

  Rectal cancer is usually treated by surgical resection of the rectum or anorectal resection with a permanent stoma. Major rectal resections are associated with postoperative complications, such as genitourinary dysfunction and impaired bowel function. Local excision (LE) of early rectal cancer (ERC) offers a definitive treatment option that may avoid these long-term complications. The challenge is to identify tumors suitable for LE. The main aim of this thesis was to assess whether a bisacodyl micro-enema could improve diagnostic performance of MRI in ERC. Diagnostic performance was assessed by two blinded readers who evaluated MRI scans performed after administration of a bisacodyl micro-enema in 73 patients with suspected ERC. In addition, 50 patients underwent MRI both with and without a bisacodyl micro-enema, enabling intra-individual comparisons of the micro-enema's effects on rectal physiology, morphology, image quality, patient tolerance, and diagnostic accuracy. The bisacodyl micro-enema led to a significant increase in submucosal width, luminal fluid volume, and tumor conspicuity. Image quality improved, while patient-reported acceptance remained unchanged. Diagnostic performance was good, with areas under the receiver operating characteristic curve (AUC-ROC) of 0.92 for Reader 1 and 0.85 for Reader 2. Increased reader confidence led to a significant improvement in diagnostic performance.

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