Autoimmune pancreatitis: an illustrated guide to diagnosis

Autoimmune pancreatitis (AIP) remains one of the rarer forms of pancreatitis but has become increasingly well recognized and widely diagnosed as it is an important differential, particularly due to the dramatic response to appropriate therapy. It is now best considered as part of a multisystem disease and the notion of "IgG4-related systemic sclerosing disease" has become widely recognized as the number of extra-pancreatic associations of AIP grows. More recently AIP has been classified into two subtypes: lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct-centric pancreatitis (IDCP) with distinct geographical, age and sex distributions for the two subtypes, in addition to different pathological characteristics. The role of imaging is crucial in AIP and should be considered in conjunction with clinical, serological, and histopathological findings to make the diagnosis. Radiologists are uniquely placed to raise the possibility of AIP and aid the exclusion of significant differentials to allow the initiation of appropriate management and avoidance of unnecessary intervention. Radiological investigation may reveal a number of characteristic imaging findings in AIP but appearances can vary considerably and the focal form of AIP may appear as a pancreatic mass, imitating pancreatic carcinoma. This review will illustrate typical and atypical appearances of AIP on all imaging modes. Emphasis will be placed on the imaging features that are likely to prove useful in discriminating AIP from other causes prior to histopathological confirmation. In addition, examples of relevant differential diagnoses are discussed and illustrated.

Intrahepatic arterioportal shunting and anomalous venous drainage: understanding the CT features in the liver

The increased use of high-contrast volume, arterial-phase studies of the liver has demonstrated the frequent occurrence of arterioportal shunts within both the cirrhotic and non-cirrhotic liver. This article sets out to explain the underlying microcirculatory mechanisms behind these commonly encountered altered perfusion states. Similarly, well-recognised portal perfusion defects occur around the perifalciform and perihilar liver and are largely caused by anomalous venous drainage via the paraumbilical and parabiliary venous systems. The underlying anatomy will be discussed and illustrated. These vascular anomalies are all caused by or result in diminished portal perfusion and are often manifest in the setting of portal venous thrombosis. The evolving concept of zonal re-perfusion following portal vein thrombosis will be discussed.

CT arterial portography in the staging of pancreatic malignancy

BACKGROUND

Detection of metastatic liver disease and malignant involvement of major peripancreatic vessels is important to determine resectability of pacreatic malignancy. Computed tomography with arterial portography (CTAP) is the most sensitive method for detection of colorectal liver metastases; it can also detect malignant vascular involvement. We have assessed CTAP in patients with pancreatic cancer considered suitable for resection after standard ultrasonography (US) and computed tomography (CT) examination.

METHOD

CTAP was performed in 18 patients (8 with a biliary stent). All patients had previous US and CT with no clear evidence of irresectability. Findings of CTAP were compared with the prior CT and with findings at operation or clinical progress.

RESULTS

CTAP suggested liver metastases in 7 patients. Three were confirmed at operation or at follow-up (sensitivity for detection of metastases in CT negative patients of 75%). There were 4 false-positive assessments (specificity, 71%). One further patient developed liver metastases within 6 mo after resection (1 false-negative). Nine patients had vascular involvement at operation. There was 1 false-positive and one false-negative assessment (sensitivity, 89% and specificity, 89%). CTAP detected vascular involvement in 4 patients in whom it was not detected by CT.

CONCLUSION

This preliminary study suggests that CTAP is a sensitive test for detection of liver metastases and vascular involvement in patients with pancreatic malignancy. This invasive test should be reserved for patients who are considered operable on the basis of other preoperative tests.

Safety and feasibility of percutaneous ultrasound guided puncture of the gall-bladder for crystal analysis

The safety and feasibility of ultrasound guided percutaneous aspiration (USPA) of bile, for bile crystal analysis was assessed critically. Forty-four patients about to undergo elective cholecystectomy underwent intended transhepatic USPA 1 h before their operation. At laparotomy a careful inspection for bile and blood leakage was made and a further sample of gall-bladder bile collected. Successful USPA occurred in 40 of the 44 patients. The four unsuccessful cases each had a gall-bladder packed with stones and contained virtually no bile. Three patients developed bile leak after transperitoneal (n = 2) and transhepatic (n = 1) puncture of the gall-bladder and another patient lost 100 mL of blood. Microscopic analysis of paired bile samples confirmed that gall-bladder bile (as opposed to hepatic bile) had always been aspirated. Ultrasound guided percutaneous aspiration of bile offers a simple and promising alternative to duodenal intubation, but considerable experience is required before it can be recommended as its replacement.

Hepatobiliary candidiasis in chronic lymphatic leukaemia

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Experience with a combined percutaneous and endoscopic approach to stent insertion in malignant obstructive jaundice

A non-operative method of palliation in malignant obstructive jaundice was used in 14 patients in whom a biliary stent could not be placed endoscopically. A guide wire was manipulated through the obstructing lesion through the percutaneous transhepatic route and retrieved through an endoscope. The stent was then fed through the endoscope over the guide wire and across the biliary stricture. There were no early complications, and worth-while palliation was obtained in most cases. The success rate for placing an endoscopic stent increased in this unit from 69 to 97% with the introduction of this technique.

Duplex ultrasound assessment of femorodistal grafts: correlation with angiography

Fifty-eight grafts have been assessed using duplex scanning and ankle brachial pressure indices. This assessment is compared with the findings by angiography. Eighteen grafts were occluded and 40 patent. Duplex scanning defined graft status with a greater accuracy than pressure indices. Pressure indices alone would not differentiate "satisfactory" grafts from those with localised, haemodynamically significant disease. Only 55% of those grafts with localised stenoses demonstrated a fall of greater than 0.2 in ankle brachial pressure index after exercise. When the information obtained using pressure indices and duplex scanning was combined non-invasive assessment had a sensitivity of 86% and specificity of 94% for detection of localised, haemodynamically significant disease in patent grafts. Haemodynamically significant disease, as defined by angiography, can be detected and localised with duplex scanning complementing the use of pressure indices in graft assessment.