Multiplanar reformations and minimum intensity projections using multi-detector row CT for assessing anomalies and disorders of the pancreaticobiliary tree

A comparative study of multi-detector CT portography versus endoscopy in evaluation of gastro-esophageal varices in portal hypertension patients

Background

Portal hypertension is a major complication resulting from obstruction of portal blood flow, like cirrhosis or portal vein thrombosis, that leads to portal hypertension. MDCT angiography has become an important tool for investigation of the liver as well as potentially challenging varices by detailing the course of these tortuous vessels. This information is decisive for liver transplantation as well as for common procedures in which an unexpected varix can cause significant bleeding.

Results

This study included an assessment of 60 cases of portal hypertension (28 males and 32 females), their age ranged from 42 to 69 years (mean age = 57.2 ± 6.63). All patients were diagnosed with portal hypertension, underwent upper GI endoscopy followed by a triphasic CT scan with CT angiographic assessment for the screening of gastro-esophageal varices.

CT is highly sensitive as compared to upper GI endoscopy (sensitivity 93%) in detecting esophageal varices. Gastric varices detected by CT in 22 patients (37%) compared to 14 patients (23%) detected by endoscopy. While paraesophageal varices were detected in 63% of patients and retro-gastric varices in 80% of patients that were not visualized by endoscopy. Our study reported that the commonest type of collaterals were the splenic collaterals, and we also found there is a significant correlation between the portal vein diameter and the number of collaterals as well as between the portal vein diameter and splenic vein diameter.

Conclusions

Multi-slice CT serves as an important non-invasive imaging modality in the diagnosis of collaterals in cases of portal hypertension. CT portography can replace endoscopy in the detection of high-risk varices. It also proved that there is a correlation between portal vein diameter, splenic vein diameter, and number of collaterals.

Multiphase multidetector-row CT reveals different patterns of hepatic portal venous gas and pneumobilia

Hepatic portal venous gas and pneumobilia (PB) are uncommon findings, indicating the accumulation of gas in the portal vein and its branches and in the biliary tree, respectively. Aims of this retrospective, descriptive study were to describe the computed tomographic (CT) features and visualization techniques of hepatic portal venous gas (HPVG) and PB in a group of small animal veterinary patients. The CT data of patients with HPVG and PB were retrospectively reviewed. Thin-section multiplanar reformatting and minimum intensity projection (MinIP) views were used to assess the acquired volume dataset. The CT features recorded were as follows: amount, aspect, distribution, and localization of the gas in the liver. Five patients were included (four dogs and one cat), two presenting HPVG and three with PB. Gas in HPVG presented a peripheral location, whereas in PB was characterized by a central location. The aspect of the gas was tubular in case of HPVG and mixed tubular and rounded in PB. An analogous number of animals between the two groups showed comparable amount (mild, moderate, and severe) and distribution (diffuse and focal). Thin-section CT can detect the presence of gas in the liver, and a combination of two-dimensional and thin-slab MinIP can differentiate between HPVG and PB in dogs and cats. The distinctive features are peripheral versus central location and tubular versus rounded aspect of the gas.

Imaging biliary strictures--a pictorial review

The diagnosis of biliary diseases may be delayed or missed because of an unpredictable clinical course and presentation. Some biliary diseases carry the risk of morbidity and mortality and are difficult to treat. The purpose of this article is to revisit the various causes and the appearances of biliary strictures on different imaging modalities and to emphasize the role of magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) in their evaluation compared with endoscopic retrograde cholangiopancreatography. MRI with MRCP is advantageous to endoscopic retrograde cholangiopancreatography for being a 1-stop shop to provide biliary, soft tissue, and vascular information that is helpful for planning intervention or surgery. Thus it serves as a superb imaging modality for the evaluation of biliary strictures.

MDCT evaluation of the pancreas: nuts and bolts

Multidetector-row CT (MDCT) imaging of the pancreas has important roles in diagnosis, staging, and treatment monitoring of a vast array of pancreatic diseases. Optimizing MDCT protocols not only requires an understanding of expected pathologies but also must take into account cumulative radiation dose considerations.

Fluid collections in and around the pancreas in acute pancreatitis

The advent of computed tomographic scan with its wide use in the evaluation of acute pancreatitis has opened up a new topic in pancreatology i.e. fluid collections. Fluid collections in and around the pancreas occur often in acute pancreatitis and were defined by the Atlanta Symposium on Acute Pancreatitis in 1992. Two decades since the Atlanta Conference additional experience has brought to light the inadequacy and poor understanding of the terms used by different specialists involved in the care of patients with acute pancreatitis when interpreting imaging modalities and the need for a uniformly used classification system. The deficiencies of the Atlanta definitions and advances in medicine have led to a proposed revision of the Atlanta classification promulgated by the Acute Pancreatitis Classification Working Group. The newly used terms "acute peripancreatic fluid collections," "pancreatic pseudocyst," "postnecrotic pancreatic/peripancreatic fluid collections," and "walled-off pancreatic necrosis" are to be clearly understood in the interpretation of imaging studies. The current treatment methods for fluid collections are diverse and depend on accurate interpretations of radiologic tests. Management options include conservative treatment, percutaneous catheter drainage, open and laparoscopic surgery, and endoscopic drainage. The choice of treatment depends on a correct diagnosis of the type of fluid collection. In this study we have attempted to clarify the management and clinical features of different types of fluid collections as they have been initially defined under the 1992 Atlanta Classification and revised by the Working Group's proposed categorization.

Comparison of three-dimensional negative-contrast CT cholangiopancreatography with three-dimensional MR cholangiopancreatography for the diagnosis of obstructive biliary diseases

PURPOSE

The purpose of our study was to compare three-dimensional (3D) negative-contrast CT cholangiopancreatography (3D-nCTCP) with 3D MR cholangiopancreatography (3D-MRCP) for the diagnosis of obstructive biliary diseases.

MATERIALS AND METHODS

3D-nCTCP and 3D-MRCP were performed on seventy clinically documented obstructive biliary diseases patients. The accuracy of each technique in determining the location and cause of biliary obstruction was evaluated compared with the final clinical diagnoses.

RESULTS

Both methods achieved 100% of accuracy in the diagnosis of the presence and location of biliary obstruction, and had a similar sensitivity, specificity, accuracy in differentiating benign from malignant biliary obstruction or calculous from noncalculous biliary obstruction (p>0.05). At 3D-nCTCP, six patients with stones were misinterpreted as cholangitis (N=2), papillitis (N=3), or bile duct adenocarcinoma (N=1); two metastases were mistaken as acute pancreatitis or pancreatic head carcinomas, and one intrahepatic cholangiocarcinoma was misled as bile duct adenoma. At 3D-MRCP, one small stone, one ampullary adenoma, and one intrahepatic cholangiocarcinoma were mistaken as cholangitis, ampullary stone, and intrahepatic bile duct stone, respectively, and three gallbladder carcinomas and another intrahepatic cholangiocarcinoma were misdiagnosed as hilar cholangiocarcinoma (N=3) or common hepatic duct stone (N=1); four metastases were mistaken as pancreatic head carcinomas (N=3) or distal cholangiocarcinoma (N=1). The overall accuracy in making specific diagnosis of the cause of biliary obstruction was 87.1% for 3D-nCTCP and 84.3% for 3D-MRCP, respectively, (p>0.05).

CONCLUSION

3D-nCTCP has the similar effects as 3D-MRCP for the diagnosis of biliary obstruction and, the location and the cause of biliary obstruction. In view of selected cases contraindications for MRI, 3D-nCTCP is a potential substitute.

MR imaging and CT of the biliary tract

Magnetic resonance (MR) imaging and computed tomography (CT) can be useful in the diagnosis of biliary disease, with both modalities allowing detailed evaluation of the biliary tract. Careful interrogation of the images is critical, regardless of modality. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section imaging. Smooth, concentric short-segment strictures favor a benign cause, whereas abrupt, eccentric long-segment strictures favor a malignancy. At MR imaging, extrabiliary entities such as crossing vessels or metallic clip artifact may mimic strictures and should not be mistaken for disease. A stone is the most common biliary filling defect and may occur in the absence of dilated ducts. Stones commonly have a lamellated, geometric shape and are found in a dependent portion of the duct. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Improved diagnosis of biliary disease can be achieved with a knowledge of the benefits and limitations of modern MR and CT cholangiographic techniques, including the use of biliary-excreted contrast material and of various postprocessing techniques. Familiarity with the radiologic appearances of the duct lumen, wall, and surrounding structures is also important for accurate image interpretation. The rapidly evolving technology for both MR imaging and CT of the biliary tract will continue to present radiologists with opportunities as well as challenges.

Evaluation of patients with esophageal varices after endoscopic injection sclerotherapy using multiplanar reconstruction MDCT images

OBJECTIVE

The purpose of our study was to assess the relationship between hemodynamic changes in portosystemic collaterals and the prognosis of patients with esophageal varices after endoscopic injection sclerotherapy using multiplanar reconstruction (MPR) MDCT images.

SUBJECTS AND METHODS

The subjects of this prospective study were 53 patients who underwent endoscopic injection sclerotherapy for esophageal varices. We evaluated the reconstructed MPR images of portosystemic collaterals before and after endoscopic injection sclerotherapy. Patients were divided into three groups based on the rate of change in the diameter of the feeding vessel into complete eradication (group A), narrowing (group B), and no change (group C). We analyzed the relationship between hemodynamic change in portosystemic collaterals and prognosis.

RESULTS

The left gastric vein, posterior gastric vein, and left gastric vein plus posterior gastric vein were the main feeding vessels (n=44 [83%] of patients, n=5 [9%], and n=4 [8%], respectively). The proportions of patients of groups A, B, and C were 19% (n=10), 24% (n=13), and 57% (n=30), respectively. The relapse-free rates at 2 years after endoscopic injection sclerotherapy were 100%, 65%, and 52% in groups A, B, and C, respectively (p<0.05). For group C, the relapse-free rate at 2 years after endoscopic injection sclerotherapy of patients with a large-diameter paraesophageal vein (>or= 3 mm, 63%) was significantly higher than in those with a small-diameter paraesophageal vein (<3 mm, 36%; p<0.05). However, there were no significant differences in the survival rate among the three groups.

CONCLUSION

MPR MDCT images on portosystemic collaterals can accurately predict relapse of esophageal varices after endoscopic injection sclerotherapy.