Nonalcoholic, nonbiliary pancreatitis: cross-sectional imaging spectrum. AJR Am J Roentgenol. 2010;195:67-75. [PMID: 20566798 DOI: 10.2214/ajr.09.4048]

Clinicoradiological appraisal of 'paraduodenal pancreatitis': Pancreatitis outside the pancreas!

Purpose:

Paraduodenal pancreatitis (PP) is a unique form of focal chronic pancreatitis that selectively involves the duodenum and aberrant pancreatic tissue located near the minor papilla (beyond the pancreas proper). The pseudotumoral nature of the disease often generates considerable clinical quandary and patient apprehension, and therefore merits a better understanding. The present study appraises the clinicoradiological manifestations of PP in 33 patients.

Materials and Methods:

Clinical, laboratory, and radiological manifestations of 33 patients of PP treated in gastroenterology/hepatology and hepato-pancreatico-biliary surgery units during June 2010-August 2014 were retrospectively reviewed.

Results:

All patients were young to middle-aged men (100%) with history of alcohol abuse (93.9%) and/or smoking (42.4%), who presented either with acute or gradually worsening abdominal pain (90.9%). Pancreatic enzymes and serum tumor markers remained normal or were mildly/transiently elevated. Cystic variant was detected in 57.6% (solid in 42.4%); the disease remained confined to the groove/duodenum (pure form) in 45.4%. Medial duodenal wall thickening with increased enhancement was seen in 87.87 and 81.81%, respectively, and duodenal/paraduodenal cysts were seen in 78.78%. Pancreatic calcifications and biliary stricture were seen 27.3% patients. Peripancreatic arteries were neither infiltrated nor encased.

Conclusion:

PP has a discrete predilection for middle-aged men with history of longstanding alcohol abuse and/or smoking. Distinguishing imaging findings include thickening of the pancreatic side of duodenum exhibiting increased enhancement with intramural/paraduodenal cysts. This may be accompanied by plate-like scar tissue in the groove region, which may simulate groove pancreatic carcinoma. However, as opposed to carcinoma, the peripancreatic arteries are neither infiltrated nor encased, rather are medially displaced.

Assessment of exocrine pancreatic function by secretin-stimulated magnetic resonance cholangiopancreaticography and diffusion-weighted imaging in healthy controls

PURPOSE

To characterize and quantify exocrine pancreatic function by secretin-stimulated magnetic resonance cholangiopancreaticography (s-MRCP) and diffusion-weighted imaging (DWI) in healthy subjects and compare these findings to morphological features, ie, pancreatic volume and secretin-stimulated peak bicarbonate concentration measured in pancreatic juice.

MATERIALS AND METHODS

Pancreatic magnetic resonance imaging (MRI) (1.5 T) was performed in 20 healthy volunteers among which 10 underwent gastroscopy with duodenal intubation. MRI included T2-weighted imaging and DWI acquired before and 1, 5, 9, and 13 minutes after secretin administration. Secreted pancreatic juice volumes were calculated based on the sequential T2-weighted images and pancreatic volumes and apparent diffusion coefficient (ADC) values were estimated.

RESULTS

The mean pancreatic secretion rate declined from 9.5 mL/min at 1-5 minutes (postsecretin) to 2.9 mL/min at 9-13 minutes. Pancreatic head ADC values significantly increased from baseline (1.29 × 10(-3) mm(2) /s) to 1 minute postsecretin (1.48 × 10(-3) mm(2) /s) (P = 0.003). Secreted pancreatic juice volume at 1 minute after secretin correlated positively with peak bicarbonate concentration (n = 10, P = 0.05).

CONCLUSION

Secretin-stimulated MRCP and DWI can characterize and quantify exocrine pancreatic function in healthy subjects. These imaging methods may prove relevant for patients with exocrine pancreatic dysfunction.

The role of pancreatic imaging in monogenic diabetes mellitus

In neonatal diabetes mellitus resulting from mutations in EIF2AK3, PTF1A, HNF1B, PDX1 or RFX6, pancreatic aplasia or hypoplasia is typical. In maturity-onset diabetes mellitus of the young (MODY), mutations in HNF1B result in aplasia of pancreatic body and tail, and mutations in CEL lead to lipomatosis. The pancreas is not readily accessible for histopathological investigations and pancreatic imaging might, therefore, prove important for diagnosis, treatment, and research into these β-cell diseases. Advanced imaging techniques can identify the pancreatic features that are characteristic of inherited diabetes subtypes, including alterations in organ size (diffuse atrophy and complete or partial pancreatic agenesis), lipomatosis and calcifications. Consequently, in patients with suspected monogenic diabetes mellitus, the results of pancreatic imaging could help guide the molecular and genetic investigation. Imaging findings also highlight the critical roles of specific genes in normal pancreatic development and differentiation and provide new insight into alterations in pancreatic structure that are relevant for β-cell disease.

Cystic dystrophy of the duodenal wall is not always associated with chronic pancreatitis

Cystic dystrophy of the duodenal wall is a rare form of the disease which was described in 1970 by French authors who reported the presence of focal pancreatic disease localized in an area comprising the C-loop of the duodenum and the head of the pancreas. German authors have defined this area as a “groove”. We report our recent experience on cystic dystrophy of the paraduodenal space and systematically review the data in the literature regarding the alterations of this space. A MEDLINE search of papers published between 1966 and 2010 was carried out and 59 papers were considered for the present study; there were 19 cohort studies and 40 case reports. The majority of patients having groove pancreatitis were middle aged. Mean age was significantly higher in patients having groove carcinoma. The diagnosis of cystic dystrophy of the duodenal wall can now be assessed by multidetector computer tomography, magnetic resonance imaging and endoscopic ultrasonography. These latter two techniques may also add more information on the involvement of the remaining pancreatic gland not involved by the duodenal malformation and they may help in differentiating “groove pancreatitis” from “groove adenocarcinoma”. In conclusion, chronic pancreatitis involving the entire pancreatic gland was present in half of the patients with cystic dystrophy of the duodenal wall and, in the majority of them, the pancreatitis had calcifications.

Part 2: CT characterisation of pancreatic neoplasm: tumour mimics

There are numerous pancreatic and peripancreatic conditions that can mimic pancreatic neoplasms. Many of these can be confidently diagnosed on computed tomography (CT), while others will require further imaging. Knowledge of these tumour mimics is important to avoid misclassification of benign conditions as malignant and to avoid unnecessary surgery. Mimics can be grouped as parenchymal, vascular, biliary and peripancreatic. These are discussed and illustrated in this review.