SS 1401 - Pancreas and bile ducts: imaging assessment
Definition of age dependent reference values for diameter of the common bile duct and pancreatic duct on MRCP from a population based cohort study
Purpose: To define new reference values for diameters of pancreaticobiliary ducts on magnetic resonance cholangiopancreatography (MRCP) in general population and to identify factors influencing duct size.
Methods and Materials: Study subjects were recruited from the population based Study of Health in Pomerania (SHIP) and had whole body MRI + MRCP (1,5T). Diameters of pancreatic duct (PD) and common bile duct (CBD) were measured on MRCP before and after administration of secretin by an investigator blinded to other subject data.
Results: 1,385 subjects were initially scanned, 865 measured PDs and 938 CBDs were included for further analysis (median age 53y, 48.5% female). Subjects were excluded for missing data or evidence of pancreaticobiliary disease. The diameters increased with age (PD median (range) 1.-3. Quartile: 20-29y 1,33mm (1.20 - 1.57), >70y 2.49 (1.85 - 3.01); CBD median (range) 1.-3. Quartile: 20-29y 4.53 (3.87 - 5.17), >70y 6.50 (5.10 - 8.23)) and the historic upper limit of normal of 3mm for PD and 7mm for CBD were exceeded by 11% and 18.2% respectively. Subjects that underwent cholecystectomy presented with significantly increased diameter of CBD, but not PD (CBDw/oCCE: 5.30mm±1.893 SD vs. CBDw/CCE: 8.18mm±2.841 SD, p<0.01; PDw/oCCE: 1.84mm±.778 SD vs. PDw/CCE: 2.06mm±.868 SD, p>0.01).
Conclusion: Up to 18% of healthy volunteers would have undergone diagnostic workup for enlarged CBD or PD above the current reference standard. The width of the pancreaticobiliary ducts increases in an age dependent manner in asymptomatic volunteers. An increase of the CBD after cholecystectomy can be observed, the PD remains unaffected.
CT texture analysis of downstaged ductal adenocarcinoma after chemoteraphy in predicting treatment response
Purpose: To evaluate the added value of CT texture analysis in the estimation of tissue changes in resected ductal adenocarcinoma after chemotherapy.
Methods and Materials: Patients with ductal adenocarcinoma downstaged after neoadjuvant treatment and therefore resected were included in this study. All the tumours were unresectable or borderline resectable at first evaluation. A pre-treatment and post-treatment CT study were obtained. The pancreatic phase of pre- and post-treatment CT study were used to evaluate the texture analysis. Tumour volume reduction was obtained in all cases based on which successfully tumour resection was performed in all cases. CT texture analysis results (Mean Value, Variance, Skewness, Kurtosis, Entropia) were compared by using Wilcoxon correlation test.
Results: 17 patients reached the resectable stage after neoadjuvant treatment. CT texture analysis was finalized in all cases. The comparison between Mean Value, Variance, Skewness and Entropia pre-treatment (MV median = 1082.70; V median = 876.31; S median = -0.23; E = 0,5520) in respect to post-treatment results (MV median = 1081.10; V median = 28.14; S median = - 0.09; E = 0,5520) shows no statistical significant difference (p > 0.05). The comparison between Kurtosis pre-treatment (K median=0.34) and Kurtosis post-treatment (K median -0.51) shows statistical significant difference (p < 0.05). Pathological correlation were performed.
Conclusion: This preliminary results on CT texture analysis of downstaged ductal adenocarcinoma show that this evaluation may represent an added value in the judgment of changes in tumour tissue, especially in those cases of ductal adenocarcinoma with no evident downsizing after chemotherapy.
Patient-adapted respiratory training improves image quality of respiratory-triggered 3D MRCP in painful pancreaticobiliary disorders
Purpose: To compare the image quality of respiratory-triggered magnetic resonance cholangiopancreatography (RT-MRCP) with and without a patient-adapted respiratory training before the examination, in clinical patients with painful pancreaticobiliary disorders.
Methods and Materials: Hospitalised patients with painful pancreaticobiliary disorders who were scheduled for MRCP study were prospectively enrolled (n=31). The maximal numerical rating scale (NRS) of abdominal pain during the course of disease and the immediate NRS before the MRCP examination were recorded. Patient-adapted respiratory training was conducted before the examination. A sex- and age-matched group of patients with painful pancreaticobiliary diseases who underwent MRCP during the same time period served as control (n=62), who received ordinary instructions only. Acquisition time was recorded. General image quality, visualization of 12 segments of the pancreaticobiliary tree and diagnostic confidence based on 3D MRCP images were rated on a five-point scale and compared between the two groups.
Results: Maximal and immediate NRS of pain was comparable between the two groups. Image quality and diagnostic confidence were significantly improved (p<0.01 and p=0.02) in patients receiving respiratory training. Visualisation of left intrahepatic duct (p=0.02 for the trunk and p<0.01 for medial and lateral branches) and pancreatic duct (p<0.01 for head, body and tail segments) was also significantly better. The other segments showed no significant difference. The acquisition time was shorter (176±54s vs 253±67s, p<0.01) in the group with patient-adapted respiratory training.
Conclusion: Patient-adapted respiratory training is feasible in clinical practice and improves the image quality of RT-MRCP in patients with painful pancreaticobiliary disorders.
Purpose: The aim of this study was to investigate the value of contrast-enhanced ultrasound (CEUS) for evaluating biliary obstruction and in differentiating between benign and malignant causes.
Methods and Materials: Between November 2006 and September 2016, 124 patients with bile duct dilatation without visible cause in baseline ultrasound underwent CEUS study. All ultrasound studies were performed by the same radiologist .The enhancement and posterior washout were analysed in real time all along the study duration (5’). Final diagnosis provided by CEUS was compared with histologic diagnosis (47.58%) or with radiologic follow-up with TC, RM or ERCP.
Results: Final diagnoses included 89 malignant lesions (cholangiocarcinoma n=41, pancreatic carcinoma n=19, metastases n=16, hepatocarcinoma n=4, gallbladder carcinoma n=4, ampullary carcinoma n=2, lymphoma n=2 and neuroendocrine pancreatic tumour n=1); and 34 patients with benign condition, (lithiasis or sludge n=24, pancreatitis n=2, abscess n=1, xanthogranulomatous cholecystitis n=1, pancreatic serous cystoadenoma n=1, biliar elastance loss=4 and indeterminate n=2). CEUS correctly identified 74 of 89 malignant lesions (sensibility 83,14%) and 26 of 35 benign lesions (specificity 74.28%). The positive predictive value was 89.15% while the negative predictive value was 63.41%.
Conclusion: CEUS is useful to differentiate between benign and malignant causes of biliary obstruction, improves the detection of bile duct invasion in hepatic neoplasms and permits better evaluation of intra- and extraductal extension of hilar hepatobiliary tumours.
Purpose: To investigate the impact of liver stiffness measured by MR elastography in patients with cholestasis due to biliary obstruction.
Methods and Materials: Sixty-nine patients who underwent pancreaticobiliary MR with MRE without history of diffuse liver disease were retrospectively included. Quantitative MR parameters including liver stiffness (LS), ADC, R2*, and fat fraction (FF) were measured. Laboratory results including aspartate transaminase (AST), alanine transaminase (ALT), total bilirubin (TB) were obtained. Patients were divided into two groups: patients with normal bilirubin level (group 1) and patients with cholestasis (group 2). Quantitative parameters were compared by independent t-test between two groups. Correlation between parameters was analyzed by Pearson correlation. Diagnostic performance and clinical impact of MR parameters was analyzed by ROC.
Results: Forty-nine patients classified into group 1 and twenty patients belonged to group 2. LS was higher in group 2 (3.8 ± 0.7 kPa) than group 1 (2.8 ± 0.5, p < 0.001), whereas other MR parameters were not different between two groups. There were positive correlation between LS and TB (r=0.611, P < 0.001), as well as the level of AST (r=0.350, P=0.004) and ALT (r=0.258, P=0.035). Furthermore, there was negative correlation between the degree of biliary decompression 1 week after bile drainage and LS (r= -0.71, P=0.003). When cut-off value was set at 4.0 kPa using ROC curve, the sensitivity and specificity for predicting biliary decompression was 84.6% and 100%, respectively.
Conclusion: LS measured by MRE increased as increasing cholestasis and can be a predictive factor for biliary decompression after biliary drainage.
Validation of feasibility of MRI for measurement of depth of tumour invasion in distal bile duct cancer
Purpose: The aim of this study was to develop and validate a method for measuring depth of tumour invasion (DoI) on MRI and to investigate the diagnostic performance of measured DoI for the stratification of T classification in patients with distal bile duct cancer.
Methods and Materials: In this retrospective, institutional review board-approved study, 54 patients (30 men, 24 women; age range, 43-81 years) with distal bile duct cancer with available preoperative MRI were registered. A study coordinator and a pathologist developed ‘provisional method’ for measuring DoI based on published studies. Thereafter, ‘improved method’ was developed after compensating the defect. Two reviewers independently measured DoI on MRI using ‘improved method’ and correlations with histopathologic reference standard were evaluated by intraclass correlation (ICC). To evaluate the diagnostic performance of MRI for T classification using DoI, the study population was radiologically and histopathologically assigned into three groups according to the DoI.
Results: ICC between reviewers’ measured DoI using ‘improved method’ and histopathologic DoI was very good or good (ICC coefficient, 0.885 and 0.784) and its’ values were significantly higher than that using ‘provisional method’ (ICC coefficient, 0.501; p-value = 0.00000 and 0.00075). The overall accuracy of the use of MRI for stratifying bile duct tumours using DoI was 68.5 % to 85.2 %.
Conclusion: With the suggested method for measuring DoI on MRI in our study, we can reliably measure DoI on MRI T2-weighted image and MRI is a feasible tool for the preoperative T classification based on DoI.
Purpose: To retrospectively analyse the CT imaging features to characterise gallbladder wall thickening as benign or malignant.
Methods and Materials: CT scans obtained including the portal venous phase in 108 patients with pathologically proven benign (n = 68), uncertain of malignant potential (n = 3), or malignant (n = 41) gallbladder wall thickening were retrospectively reviewed. Two blinded readers independently analysed concentricity, evenness, mucosal smoothness and layered pattern of the gallbladder wall thickening. Presence of multiple tiny enhancing dots in the thickened gallbladder wall, so-called “strawberry dot sign”, was also investigated.
Results: Concentric and even wall thickening, smooth contour of the mucosa and double layering enhancement were significant predictors for benign gallbladder wall thickening (p<: 0.01 for each finding). Strawberry dot sign was significantly more frequent in benign wall thickening (p<: 0.01), particularly in adenomyomatosis (p>0.05). Sensitivities of strawberry dot sign in diagnosing adenomyomatosis were 92% in the reader 1 and 100% in the reader 2. On the contrary, strawberry dot sign was not observed in 70% (reader 1) and 68% (reader 2) of the cases with malignant diseases or uncertain of malignant potential entities.
Conclusion: Analysing the contour and layering of gallbladder wall thickening, and presence of strawberry dot sign on CT is helpful in differentiating benign entities from malignancy.
Bile leakages after hepatic surgery and orthotopic liver transplantation: value of Gd-EOB-DTPA-enhanced MR cholangiography
Purpose: To assess the diagnostic value of Gd-EOB-DTPA-enhanced MR cholangiography in the detection of bile leakages after hepatic surgery and orthotopic liver transplantation.
Methods and Materials: Thirty-two patients with previous hepatic resection (n=20) or orthotopic liver transplantation (n=12) underwent MR imaging at 1.5T/3T device due to strong suspicion of bile leak, based on a combination of clinical, laboratory and previous imaging findings. After the acquisition of axial T1w/T2w images and conventional MR cholangiography (thin-slab 3D FRFSE and thick-slab SSFSE T2w sequences), 3D fat-suppressed coronal and axial LAVA sequences were performed before, 20 minutes and between 25 and 120 minutes after intravenous administration of 10ml Gd-EOB-DTPA (Primovist®, Bayer HealthCare). Two radiologists in conference evaluated all the images for the presence or absence of bile leak, and its location when present. Imaging results were correlated with direct cholangiography, percutaneous drainage of fluid collection and/or imaging follow-up.
Results: A well-defined collection containing contrast material was detected in 14 out of our 32 patients (one false negative case on MRI). Gd-EOB-DTPA-enhanced MR cholangiography yielded an overall sensitivity of 93%, specificity of 100%, PPV of 100%, NPV of 94% and accuracy of 97% for the diagnosis of an active bile leak. However, the sensitivity of 20 minutes delayed MR images was 47%.
Conclusion: Gd-EOB-DTPA-enhanced MR cholangiography utilizing delayed phase images is a highly reliable technique for the detection of active bile leakages after hepatic surgery and orthotopic liver transplantation. The images obtained 25-120 minutes after hepato-biliary contrast agent injection significantly increased the detection of leaks.
Diagnostic value of Gd-EOB-DTPA-enhanced MR cholangiography in non-invasive detection of postoperative bile leakage
Purpose: To assess the value of dynamic T1-weighted (T1w) gadolinium ethoxybenzyl diethylentriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced MR Cholangiography (MRC) for the diagnosis of active bile leaks.
Methods and Materials: A total of 28 patients with suspected biliary leakage who underwent routine T2w-MRC and T1w-GD-EOB-DTPA-enhanced MRC at our institution from February 2013 to June 2016 were included in this study. The image sets were retrospectively analysed in consensus by 3 radiologists. T1-weighted -Gd-EOB-DTPA-enhanced MRC findings were correlated with clinical data, follow-up examinations and findings of invasive-/surgical procedures. Patients with positive bile leak findings in Gd-EOB-DTPA-enhanced MRC were divided in hepatobiliary phase (HBP) (20-30 min) and delayed phase (DP) group (60-390 min) according to elapsed time until detection of bile leak after Gd-EOB-DTPA injection. These groups were compared in terms of laboratory test results (total bilirubin, liver function tests) and presence of bile duct dilatation in T2w-MRC images.
Results: The accuracy, sensitivity and specificity of dynamic Gd-EOB-DTPA-enhanced T1w-MRC in detection of biliary leaks were 92.9%, 90.5%, and 100%; respectively (P<0.001). Nineteen of 28 patients had bile leak findings in MRC, with 7 patients (36.8%) in HBP group and 12 patients (63.2%) in DP group. There was no statistically significant difference in terms of laboratory test results and presence of bile duct dilatation between HBP and DP group (P>0.05).
Conclusion: Dynamic T1-weighted Gd-EOB-DTPA-enhanced MRC is a useful non-invasive diagnostic tool to detect bile leak and prolonged delayed phase imaging may be required if extravasation of Gd-EOB-DTPA is not visible in HBP.
Purpose: Percutaneous transhepatic cholangiogram (PTC) provides imaging of the biliary system. PTC is indicated for investigation and treatment of biliary obstruction. We investigate the use of PTC and factors that potentially predict outcomes.
Methods and Materials: We conducted a one-year retrospective case-note review of PTC procedures at Birmingham Heartlands hospital from September 2014. The following was recorded:-Patient: diagnosis and bloods-Procedure: intervention, antibiotics and technical success-Outcomes: bloods (day 1, 7 and month 1) and complications.
Results: 162 PTCs were performed in n=108 (59 male, mean 70.4 years). Malignant disease accounted for 76% of diagnoses, with 91% palliative cases. Baseline bloods included: bilirubin 194.73umol/L, albumin 23.09g/L and INR 1.25 with 16.3% >1.4. Procedures included 115 drains, 28 biopsies and 54 stents. Reduction in bilirubin occurred at day 1 (13.48 ±7.6), 7 (64.63 ±101.2) and persisted at month 1 (132.03 ±139.9). Sepsis occurred in 19% and fatal haemorrhagic pancreatitis developed in one patient. Hospital stay was 9.83days (±11.9) with 9% failed discharges. 7- and 30-day mortality were 12 (11%) and 28 (26%), respectively. Baseline bilirubin, haemoglobin and INR predicted mortality (p=0.015, 0.014, 0.018). Baseline albumin predicted delta bilirubin post-PTC (at all follow-up intervals p=0.02, 0.046 and 0.041) and hospital stay (p=0.002). Benign disease is a negative predictor for sepsis, p=0.006.
Conclusion: PTC is primarily used for palliative management of malignancy. It has a high technical success rate with substantial risk. Bilirubin, haemoglobin and INR should be considered in risk profiling to optimise patient selection.