Advanced Imaging Techniques for Chronic Pancreatitis

MRI and MRCP play an important role in the diagnosis of chronic pancreatitis (CP) by imaging pancreatic parenchyma and ducts. MRI/MRCP is more widely used than computed tomography (CT) for mild to moderate CP due to its increased sensitivity for pancreatic ductal and gland changes; however, it does not detect the calcifications seen in advanced CP. Quantitative MR imaging offers potential advantages over conventional qualitative imaging, including simplicity of analysis, quantitative and population-based comparisons, and more direct interpretation of detected changes. These techniques may provide quantitative metrics for determining the presence and severity of acinar cell loss and aid in the diagnosis of chronic pancreatitis. Given the fact that the parenchymal changes of CP precede the ductal involvement, there would be a significant benefit from developing MRI/MRCP-based, more robust diagnostic criteria combining ductal and parenchymal findings. Among cross-sectional imaging modalities, multi-detector CT (MDCT) has been a cornerstone for evaluating chronic pancreatitis (CP) since it is ubiquitous, assesses primary disease process, identifies complications like pseudocyst or vascular thrombosis with high sensitivity and specificity, guides therapeutic management decisions, and provides images with isotropic resolution within seconds. Conventional MDCT has certain limitations and is reserved to provide predominantly morphological (e.g., calcifications, organ size) rather than functional information. The emerging applications of radiomics and artificial intelligence are poised to extend the current capabilities of MDCT. In this review article, we will review advanced imaging techniques by MRI, MRCP, CT, and ultrasound

Advanced MR Imaging of the Pancreas

MR imaging can be optimized to evaluate a spectrum of pancreatic disorders with advanced sequences aimed to provide quantitative results and increase MR diagnostic capabilities. The pancreas remains a challenging organ to image because of its small size and location deep within the body. Besides its anatomic limitations, pancreatic pathology can be difficult to identify in the early stages. For example, subtle changes in ductal anatomy and parenchymal composition seen in early chronic pancreatitis are imperceptible with other modalities, such as computed tomography. This article reviews the application of MR imaging techniques and emerging MR sequences used in pancreas imaging

Differentiating IgG4-related sclerosing cholangiopathy from cholangiocarcinoma using CT and MRI: experience from a tertiary referring center

Purpose To compare the cross-sectional imaging findings of immunoglobulin G4-related sclerosing cholangiopathy (IgG4-SC) and cholangiocarcinoma (CCA). Methods Retrospective search of radiology and pathology databases identified 24 patients with IgG4-SC and over 500 patients with CCA from January 2009 to December 2016. Patients with no pre-treatment imaging studies available on PACS, non-contrasted imaging only, presence of mass lesions, metastatic disease or biliary stents were excluded. 17 patients with IgG4-SC and a selected group of 20 (age and gender matched) patients with CCA were obtained. Images were blinded and independently reviewed by two radiologists. Differences in proportions and means between groups were analyzed using Fishers and Mann–Whitney tests, respectively. Results Both readers identified a statistically significant difference in the presence of abrupt common bile duct narrowing between IgG4-SC and CCA (6.7% vs. 68.4%, p < 0.001; 33.3% vs. 75%, p = 0.019). No difference was seen in biliary wall thickening, wall enhancement, extrahepatic exclusive location of disease, or pancreatic duct dilation. Inter-observer variability was κ = 0.52. Total bilirubin and CA 19-9 were unable to differentiate between IgG4-SC and CCA. Serum IgG4 was positive in two of six IgG4-SC patients who were tested. Conclusion IgG4-SC and CCA share many clinical and imaging findings on CT and MRI. Abrupt bile duct cut sign strongly favors CCA. In the absence of this finding, IgG4-SC should be considered in the differential diagnosis in all cases of suspected extrahepatic CCA

Normal T1 relaxometry and extracellular volume of the pancreas in subjects with no pancreas disease: correlation with age and gender

OBJECTIVE Determine normal T1 and extracellular volume (ECV) of the pancreas in subjects with no pancreas disease and correlate with age and gender SUBJECTS AND METHODS We imaged 120 healthy subjects (age range: 20-78 years) who are on annual screening with MRI/MRCP for the possibility of pancreatic cancer. Subjects had a predisposition to develop pancreatic cancer, but no history of pancreas disease or acute symptoms. Equal number (n=60) of subjects were scanned on either 1.5 T or 3 T scanner using dual flip angle spoiled gradient echo technique incorporating fat suppression and correction for B1 field inhomogeneity. Optimization of imaging parameters were performed using a T1 phantom. ECV was calculated using pre- and post-contrast T1 of the pancreas and plasma. Regression analysis and Mann-Whitney tests were used for statistical analysis. RESULTS Median T1 on 1.5 T was 654 ms (IQR: 608-700); median T1 on 3 T was 717 ms (IQR: 582-850); median ECV on 1.5 T was 0.28 (IQR: 0.21-0.33) and median ECV on 3 T was 0.25 (IQR: 0.19-0.28). Age had a mild positive correlation with T1 (r= 0.24, p= 0.009), but not with ECV (r= 0.06, p=0.54). T1 and ECV were similar in both genders (p >0.05). CONCLUSION This study measured the median T1 and ECV of the pancreas in subjects with no pancreas disease. Pancreas shows longer T1 relaxation times in older population, whereas extracellular fraction remains unchanged. Median T1 values were different between two magnet strengths; however, no difference was seen between genders and ECV fractions

Endoscopic Unroofing of a Choledochocele

A 42-year-old man with previous laparoscopic cholecystectomy was referred for further evaluation of recurrent acute pancreatitis. Secretin-enhanced magnetic resonance cholangiopancreatography showed a 16 mm × 11 mm T2 hyperintense cystic lesion at the major papilla (Figure 1). Upper endoscopic ultrasound (EUS) showed a 15 mm × 10 mm oval, intramural, subepithelial lesion at the major papilla (Figure 2). Endoscopic retrograde cholangiopancreatography (ERCP) showed an 18-mm bulging lesion at the major papilla with normal overlying mucosa (Figure 3); injected contrast collected into a 16-mm cystic cavity (Figure 4). Findings were suggestive of type A choledochocele. A 10–12-mm freehand precut papillotomy was made with a monofilament needle-knife (Huibregtse Single-Lumen Needle Knife, Cook Medical, Bloomington, IN) using an ERBE VIO electrocautery system (ERBE USA; Marietta, GA). The incision was made as long as safely possible in an attempt to open the choledochocele completely and thus expose its walls and contents. We used a standard pull sphincterotome and ERBE electrocautery to perform the pancreatic sphincterotomy, followed by placement of a pancreatic stent. Biliary sphincterotomy was performed using the same technique (settings for needle-knife and pull sphincterotomies: Endocut I, blend current, effect 2/duration 2/interval 3). Biopsies of the inverted choledochocele showed biliary mucosa and duodenal columnar epithelium with inflammation and fibrosis, and no dysplasia. Follow-up ERCP at 4 weeks showed adequate unroofing of the choledochocele (Figure 5); the pancreatic stent was subsequently removed. The patient reported no recurrence of acute pancreatitis at 6-, 12-, and 18-month follow-up intervals

Benign Hepatic Nodules Mimicking Hepatocellular Carcinoma in the Setting of Fontan-associated Liver Disease: A Case Report

Fontan procedure, in which systemic circulation is redirected into pulmonary circulation by a baffle, is a palliative surgical strategy for patients born with single ventricle congenital heart disease. Hemodynamic changes secondary to Fontan procedure, also termed as Fontan physiology, result in end-organ damage, especially of the liver. Fontan-associated liver disease (FALD) represents a spectrum of pathologies ranging from mild liver fibrosis to advanced liver cirrhosis and hepatocellular carcinoma (HCC). Hepatic nodules, some of which have been documented as HCC in several case series and reports, are a recognized complicated feature of FALD. Herein, we report a case with benign hepatic nodules mimicking HCC by imaging characteristics, emphasizing the fact that arterially enhancing lesions with delayed washout appearance may reflect benign regenerative or focal nodular hyperplasia-like nodules in patients with Fontan physiology

Computerized Tomography of the Acute Left Upper Quadrant Pain

The purpose of this study was to evaluate the clinical utility of computerized tomography (CT) of the abdomen in the emergent setting of left upper quadrant pain. One hundred patients (average age: 45, range: 19–93 years, female: 57 %, male: 43 %) who presented to the emergency department (ED) and underwent CT scanning of abdomen with the given indication of left upper quadrant pain were included in this study. The results from CT examinations were compared to final diagnoses determined by either ED physician or clinician on a follow-up visit. Sensitivity of CT was 69 % (95 %CI: 52–83 %) for 39 patients who eventually were diagnosed with an acute abdominal abnormality. Twenty-seven patients had an acute abnormal finding on abdominal CT that represented the cause of the patient’s pain (positive predictive value of 100 %, 95 %CI: 87–100 %). Of the remaining 73 patients with negative CT report, 12 were diagnosed clinically (either in the ED or on follow-up visit to specialist) with a pathology that was undetectable on the CT imaging (negative predictive value of 83 %, 95 %CI: 73–91 %). None of the remaining 61 patients with negative CT were found to have pathology by clinical evaluation (specificity of 100 %, 95 %CI: 94–100 %). CT is a useful examination for patients with acute left upper quadrant pain in the emergency department setting with moderate sensitivity and excellent specificity

Chemotherapy-related complications in the kidneys and collecting system: an imaging perspective

Nephrotoxicity is a common adverse effect of many chemotherapeutic agents. The agents most commonly associated with chemotherapy-associated nephrotoxicity are methotrexate, semustine, streptozocin, mithramycin, and cisplatin. Certain chemotherapeutic agents have adverse effects on the kidneys and urothelium that can be visualized radiographically, including cystic change, interstitial nephritis, papillary necrosis, urothelial changes, haemorrhagic cystitis, acute tubular necrosis, and infarction. This review focuses on imaging features identifying complications of chemotherapy in the kidneys and collecting system and provides didactic cases to alert referring clinicians

Metachronous gastric metastasis from lung primary, with synchronous pancreatic neuroendocrine carcinoma

The finding of gastric metachronous metastasis, several years after the diagnosis of primary lung large cell carcinoma is rare and incidental. Even more extremely rare is the finding of a synchronous primary pancreas cancer. EUS-FNA with immunohistochemistry is useful for diagnosing metastatic lesions and differentiating those from synchronous primary lesions

The Value of Secretin-Enhanced MRCP in Patients With Recurrent Acute Pancreatitis

OBJECTIVE The purpose of this study is to assess the additional value of secretin-enhanced MRCP over conventional (non–secretin-enhanced) MRCP in diagnosing disease in patients with recurrent acute pancreatitis. MATERIALS AND METHODS A retrospective review of a radiology database found 72 patients with recurrent acute pancreatitis who had secretin-enhanced MRCP and ERCP correlation within 3 months of each other between January 2007 and December 2011. Of these patients, 54 had no history of pancreatic tumor or surgery and underwent MRI more than 3 months after an episode of acute pancreatitis. In addition, 57 age- and sex-matched control subjects with secretin-enhanced MRCP and ERCP correlation and without a diagnosis of recurrent acute pancreatitis or chronic pancreatitis were enrolled as the control group. All studies were anonymized, and secretin-enhanced MRCP images (image set A) were separated from conventional 2D and 3D MRCP and T2-weighted images (image set B). Image sets A and B for each patient were assigned different and randomized case numbers. Two blinded reviewers independently assessed both image sets for ductal abnormalities and group A image sets for exocrine response to secretin. RESULTS There were statistically significantly more patients with recurrent acute pancreatitis with reduced exocrine function compared with patients in the control group (32% vs 9%; p < 0.01) on secretin-enhanced images. Patients with recurrent acute pancreatitis were more likely to have side branch dilation (p = 0.02; odds ratio, 3.6), but not divisum, compared with the control group. Secretin-enhanced images were superior to non–secretin-enhanced images for detecting ductal abnormalities in patients with recurrent acute pancreatitis, with higher sensitivity (76% vs 56%; p = 0.01) and AUC values (0.983 vs 0.760; p < 0.01). CONCLUSION Up to one-third of patients with recurrent acute pancreatitis showed exocrine functional abnormalities. Secretin-enhanced MRCP had a significantly higher yield for ductal abnormalities than did conventional MRI and should be part of the MRCP protocol for investigation of patients with recurrent acute pancreatitis