Objectives:To identify the optimal time for MRI response evaluation after chemoradiotherapy (CRT) in squamous cell carcinoma of the anus (SCCA) and to employ combined T2+diffusion-weighted MRI tumour regression grade (comrTRG). Methods:We assessed the positive and negative predictive values (PPV, NPV) of post-treatment MRI in a retrospective mono-centre diagnostic accuracy study that prospectively included consecutive patients treated between 2013 and 2017. Index tests were MRI at 6-, 12-, and 24-weeks post-treatment (6w, 12w, and 24w) to detect locoregional treatment failures (LRTF). Clinical outcome served as reference standard. Tumour regression was assessed using comrTRG based on radiological reports. Mixed-effects logistic regression was used to compare the comrTRG score across time points. The analyses were stratified by patients' T/N stage and human papillomavirus (HPV) status. Results:For 127 included patients (62 years ± 11 [mean ± SD]; 92 women), 261 post-treatment MRI reports (6w: n = 45, 12w: n = 125, 24w: n = 91) were scored using comrTRG. LRTF occurred in 13 patients; 12/13 were high-risk patients (T3/T4, N+, or HPV-negative); 1/13 progressed early (<24 weeks). The rate of radiologic complete response (comrTRG1) increased over time (6w: 27%, 12w: 66%, 24w: 75%), while the rate of indeterminate (comrTRG2) and minor definite tumour (comrTRG3) decreased. PPV of MRI increased over time: 6w: 33% (95%CI: 9.9%-65.1%), 12w: 46% (16.7%-76.6%), and 24w: 88% (47.3%-99.7%). NPV was stable high >90%. Conclusions:MRI performed more reliably after 24 weeks. Timely assessment may aid early LRTF detection. Tailoring follow-up with frequent MRI scans may be sufficient for high-risk patients. Combined mrTRG is practical for describing response in SCCA. Advances in knowledge:Post-treatment MRI assessment at later time points is preferable in SCCA to avoid inconclusive imaging and unnecessary salvage surgery. The introduced comrTRG is a practical tool for response evaluation. Registration:ClinicalTrials.gov: NCT01937780.

To assess the effects of a bisacodyl micro-enema on rectal physio-morphology, image quality, and patient acceptance when used as preparation before MRI of rectal tumors. In this prospective single-center study, we made an intra-individual comparison of patients with suspected early rectal cancer who all completed MRI without (MRex) and with (MRin) a bisacodyl micro-enema. The width and the anal-oral extension of the submucosal edema in the healthy rectal wall, anal-oral extension of luminal fluid, and rectal distension were registered. Image artifacts were recorded with a figurative visual analog scale (fVAS), and patient acceptance with questionnaires at baseline, after MRex, and MRin. Significance levels were calculated with a t-test, the Wilcoxon signed-rank test, or McNemar’s test for paired samples and inter-reader agreement with Gwets AC1 statistics. Consecutively, 50 patients (mean age, 65 years ± 10, 26 men) were included. The median (iqr) summed width of submucosa (MRex, 26 (12) mm, MRin 39 (13) mm, p < 0.01) and anal-oral fluid extension (MRex 0 (0) mm, MRin 134 (91) mm, p < 0.001) increased. Susceptibility artifacts on diffusion weighted imaging (axial plane p ≤ 0.04 and parallel plane p < 0.001) were reduced. No increase in rectal distension, motion artifacts, or side effects was registered, and the patient-reported acceptance remained unchanged. Bisacodyl significantly increased the submucosal width and extension of intraluminal fluid, did not lead to distension of the rectum, improved image quality, and was well tolerated by the patients. Question Bisacodyl micro-enema can improve MRI of early stage-rectal tumors, but the impact on rectal physio-morphology, image quality, and patient acceptance is unknown. Result Bisacodyl micro-enema increased the submucosal width and intraluminal fluid, did not distend the rectum, improved image quality, and was well tolerated by the patients. Clinical relevance Bisacodyl micro-enema represents a reliable preparation before MRI of rectal tumors and can improve imaging of early-stage cancer. This is increasingly important because of the shift toward earlier stages due to screening programs and the growing use of organ-saving treatment.

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.

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). 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. Sensitivity/specificity were for Reader1 91

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.

Background Magnetic resonance imaging (MRI) with hepatocyte specific contrast has the highest sensitivity for colorectal liver metastases but comes at high costs and long examination times. Purpose To evaluate if preoperative detection of colorectal liver metastases with less resource-consuming diffusion-weighted imaging (DWI) alone or in combination with multidetector computed tomography (MDCT) can compete with gadolinium-etoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI. Material and Methods Forty-four patients with 123 colorectal liver metastases received MDCT and Gd-EOB-DTPA-enhanced MRI including DWI before liver resection for colorectal liver metastases. Five image sets were evaluated by two radiologists. The DWI set consisted of DWI, ADC map, coronal, axial T2-weighted single-shot sequences. The DWI-T2F set contained additionally respiratory-triggered T2-weighted TSE-SPIR sequences. The MDCT set consisted of four-phase MDCT, the MDCT-DWI set also contained DWI. The CE-MRI set contained all MRI sequences including Gd-EOB-DTPA. Reference standards was histopathology and follow-up. Results CE-MRI set had highest sensitivity ( P ≤ 0.013) with 95% compared to 72%, 73%, 73%, and 87% the for DWI set, DWI-T2W-FS set, MDCT set, and MDCT-DWI set, respectively. The CE-MRI set had the highest sensitivity ( P≤0.012) for colorectal liver metastases <10 mm with 87% compared to 55%, 52%, 23%, and 58% for the DWI set, DWI-T2W-FS set, MDCT set, and MDCT-DWI set, respectively. The MDCT-DWI set improved sensitivity overall and in size-dependent subgroup analyses compared to the MDCT set ( P ≤ 0.031). The MDCT-DWI set showed the highest specificity of 98% followed by 98%, 98%, 95%, and 88% for the DWI set, DWI-T2W-FS set, MDCT set, and CE-MRI set, respectively. Conclusion The less resource and time-consuming DWI sets are inferior to Gd-EOB-DTPA-enhanced MRI for the detection of colorectal liver metastases. Gd-EOB-DTPA-enhanced MRI with its excellent sensitivity should be the preferred preoperative modality when meticulous lesion identification is essential. Combination of DWI with MDCT improved significantly sensitivity compared to each modality alone.

To assess the diagnostic accuracy of a junctional zone (JZ) thickness of ≥ 12 mm and morphological features of the JZ in MRI in diagnosing adenomyosis in a premenopausal study population. This single-center, prospective observational study consecutively enrolled 93 premenopausal women suffering from a benign gynecological condition, from September 2014 to August 2016. Institutional review board approval and written consent were obtained. All participants underwent MRI and hysterectomy with a histopathological examination. MR images were evaluated in a blinded fashion by two independent readers. The maximum junctional zone thickness (JZmax), presence of JZmax ≥ 12 mm, and any irregular appearance of the JZ (defined as irregular outer or inner borders, focal thickening, presence of high-intensity signal foci, or fingerlike indentations at the inner border) were documented, and the diagnostic performance was evaluated with the AUC, chi-square test, and multiple regression. Adenomyosis was histopathologically confirmed in 57 (61%) of the women. JZmax was not positively correlated with adenomyosis diagnosis (AUC = 0.57, p = 0.26) and did not differ significantly between those with and without adenomyosis (10.3 vs 10.1 mm, p = 0.88), nor was a cutoff of JZmax ≥ 12 mm (n = 30/57 (53%) vs n = 16/36 (44%), p = 0.29). The presence of an irregular JZ showed the best association with adenomyosis among the evaluated signs (sensitivity 74% (95% CI, 60, 85); specificity 83% (95% CI, 67, 94) (p < 0.001)). JZmax was not correlated with adenomyosis in the present premenopausal study population, but direct signs of adenomyosis such as irregularities of the JZ provided a good diagnostic accuracy. • Measuring the junctional zone thickness is of limited value for diagnosing adenomyosis with MRI and should not be used for diagnosing adenomyosis in premenopausal women with moderate disease severity. • An irregular appearance of the junctional zone, the presence of myometrial cysts, and adenomyoma appear to provide the highest specificity for diagnosing adenomyosis. • A consensus for the definition and reading of the junctional zone is needed.

BACKGROUND & AIMS: The prevalence of primary sclerosing cholangitis (PSC) among patients with inflammatory bowel disease (IBD) is unclear. Patients with IBD might be screened for PSC using magnetic resonance cholangiography (MRC). We aimed to estimate the frequency and distribution of MRC-detected lesions that indicate PSC in patients with IBD 20 years after their initial diagnosis and to identify clinical characteristics associated with these findings. METHODS: We performed a follow-up analysis of a population-based cohort of 756 patients in South-Eastern Norway diagnosed with IBD from January 1, 1990 through December 31, 1993. Of these subjects, 470 attended a follow-up evaluation 20 years later in which they were offered routine clinical blood testing and ileocolonoscopy; 322 were screened by MRC (222 with ulcerative colitis and 100 with Crohn's disease). Two radiologists independently evaluated results from the MRC examinations. RESULTS: In the MRC examination, 24 patients (7.5%) were found to have PSC-like lesions; only 7 of these patients (2.2%) were known to have PSC. One patient was initially missed and 1 had small-duct PSC, so the final prevalence of PSC was 8.1%. Extensive colitis, a high prevalence of colectomy, and chronic and continuous symptoms of IBD occurred in significantly more patients with suspected PSC than without PSC (P =.029, P =.002, and P =.012, respectively). Among patients with subclinical features of PSC, the MRC progression score for PSC increased when they were re-examined after a median 3.2 years (P =.046). CONCLUSIONS: Using MRC analysis of patients with long-term IBD, we found the prevalence of PSC to be around 3-fold higher than that detected based on symptoms. Sixty-five percent of patients had subclinical PSC associated with progressive IBD, with no biochemical abnormalities and mild disease, based on radiology findings. PSC appears to progress in patients with subclinical disease, but long-term outcomes are not known.

Pleomorphic adenoma of the parotid gland with metastases to the liver is a rare etiology of focal liver lesions, and there are no described pathognomonic imaging features. We report a patient who presented with a newly diagnosed rectal cancer and multiple cystic liver lesions suspicious of mucinous synchronous liver metastases. Following chemotherapy no reduction in the number or size of the liver lesions was observed. The patient was re-evaluated and a biopsy of a lesion was performed. The specimen showed a metastasis from a pleomorphic adenoma of the parotid gland for which the patient had been treated 20 years earlier. The case illustrates how a thorough medical history can be crucial when a standard diagnostic imaging workup for colorectal cancer metastases is uncertain, and how a biopsy, though regarded as contraindicated due to the risk of tumor cell dissemination, can be required to secure a correct diagnosis.

Background Meticulous imaging of colorectal liver metastases (CRLM) is mandatory to optimize outcome after liver resection. However, the detection of CRLM is still challenging. Purpose To evaluate prospectively if magnetic resonance imaging (MRI) with diffusion-weighted and Gd-EOB-DTPA-enhanced sequences had a better diagnostic performance for CRLM compared to computed tomography (CT) and fluorine-18 fluorodeoxyglucose positron emission tomography (PET/CT). Material and Methods Forty-six patients scheduled for resection of suspected CRLM were evaluated prospectively from September 2011 to January 2013. None of the patients had undergone previous treatment for their CRLM. Multiphase CT, liver MRI with diffusion-weighted and dynamic Gd-EOB-DTPA-enhanced sequences and low-dose PET/CT were performed. Two independent, blinded readers evaluated the examinations. The reference standard was histopathological confirmation (81/140 CRLM) or follow-up. Results A total of 140 CRLM and 196 benign lesions were identified. On a per-lesion basis, MRI had the significantly highest sensitivity overall and for CRLM < 10 mm ( P < 0.001). Overall sensitivity/specificity and PPV/NPV were 68%/94% and 89%/81% for CT, 90%/87% and 82%/93% for MRI, and 61%/99% and 97%/78% for PET/CT. For CRLM < 10 mm it was 16%/96% and 54%/80% for CT, 74%/88% and 64%/93% for MRI, and 9%/98% and 57%/79% for PET/CT. Conclusion MRI had the significantly highest sensitivity compared with CT and PET/CT, particularly for CRLM < 10 mm. Therefore, detection of CRLM should be based on MRI.

Introduction Chemotherapy has been shown to improve survival in patients with locally advanced and metastatic cholangiocarcinoma (CC). Similar data have been reported with photodynamic therapy (PDT) in combination with stent drainage. A combination of these treatment modalities might improve outcomes further, but such data are still lacking. Therefore we have performed the first randomized trial on the combination of temoporfin/PDT, stent and chemotherapy versus stent and chemotherapy only. Methods Randomized phase II trial with feasibility and toxicity as endpoints. Preliminary data on progression free survival will also be reported. Inclusion criteria were unresectable, treatment naive patients with CC confirmed by histology or cytology, need for biliary stent, bilirubin level Results Twenty patients with locally advanced and metastatic disease were included, ten patients in each arm. Eight men and twelve women, age 35-75 years. Two patients in arm A did not receive chemotherapy (ECOG>2, infection) and two patients in arm B (thrombocytopenia, study withdrawal). No serious, procedure-related complication was seen. Three cases of cholangitis were observed in both group A and B during the first 30 days. Within the next two months three additional patients in each group had cholangitis, grade 3-4. No liver abscess was observed within 30 days. Within three months, liver abscess was found in two patients, group A. Neutropenia grade 3 was observed in 2 patients in both arms, no neutropenic infection. Preliminary data on progression free survival (three still without progression, one just started) were mean 212 days in group A compared to 162 days in group B. Data on QoL will be reported. Conclusion The total number of cholangitis was equal in both groups, two abscesses were seen only in group A, more than one month after PDT. No other serious complication related to PDT was seen. Preliminary, progression free survival seems to be prolonged in group A. Depending on the final data a larger study should be considered.

e14637 Background: Patients whocannot be offered curative surgical treatment for biliary tract cancer (BTC) have a poor prognosis. Photodynamic therapy (PDT) has been shown to improve survival and quality of life in patients with unresectable BTC. A combination of treatment modalities might improve survival further, but such data are still lacking. Therefore we have performed the first randomized trial on the combination of temoporfin/PDT and chemotherapy. Here we report data on the feasibility and safety. Methods: Randomized phase II trial, planned to include 20 patients with time to progression as primary endpoint, feasibility and toxicity as secondary endpoints. Inclusion criteria were unresectable BTC confirmed by histology or cytology, need for biliary stent, bilirubin level < 50 mmol/L and no previous cancer disease. The treatment arms were: A: Stent, temoporfin / PDT followed by gemcitabin / capecitabin (GemCap). B: Stent, GemCap. Only one initial PDT treatment was given. Results: Twenty patients with locally advanced and metastatic disease were included, 10 patients in each arm. Two patients in arm B did not receive any treatment (thrombocytopenia, study withdrawal) and two patients in arm A did not receive chemotherapy (ECOG>2, infection). PDT was feasible in all 10 patients without any acute procedure-related complication. During the first 30 days, two cases of cholangitis in arm A and three in arm B were observed. Cutaneous erythema (grade 1-2) was observed after PDT in two patients. Conclusions: PDT using temoporfin in combination with chemotherapy in BTC was feasible. Restrictions to light exposure were well tolerated. PDT in combination with chemotherapy did not increase the complication rate during the first 30 days follow-up. Three months follow-up data will be available at the time for presentation. Larger prospective trials are warranted to assess the efficacy of this treatment combination.

Poster: "ECR 2016 / B-0008 / MR cholangiography screening in longstanding IBD: prevalence of bile duct pathology indicative of sclerosing cholangitis in a population based cohort" by: "A. K. Lunder1, J. R. Hov2, A. Borthne1, E. Viktil2, G. W. Johannesen3, K. Tveit4, J. Gleditsch5, M. Vatn1, A. Negard1; 1Lorenskog/NO, 2Oslo/NO, 3Skien/NO, 4Kristiansand/NO, 5Fredrikstad/NO"