Philip W. Ralls

Sonography of Diffuse Liver Disease

Sonography is often the first imaging procedure performed in the evaluation of individuals with suspected liver disease. Evaluation for biliary dilatation is always performed, because bile duct obstruction can cause abnormal liver test results, raising the suspicion of liver disease. Ultrasound is a useful but imperfect tool in evaluating diffuse liver disease. We discuss the uses and limitations of sonography in evaluating parenchymal liver disease. Sonography can show hepatomegaly, fatty infiltration of the liver, and cirrhosis, all with good but imperfect sensitivity and specificity. Sonography is of limited usefulness in acute hepatitis. Increased parenchymal echogenicity is a reliable criterion for diagnosing fatty liver. Cirrhosis can be diagnosed in the correct clinical setting when the following are present: a nodular liver surface, decreased right lobe–caudate lobe ratio, and indirect evidence of portal hypertension (collateral vessels and splenomegaly). Ultrasound plays an important role in the imaging of conditions and procedures common in patients with diffuse liver disease.

Does an infected peripancreatic fluid collection or abscess mandate operation

OBJECTIVE To assess the treatment of peripancreatic fluid collections or abscess with percutaneous catheter drainage (PCD). SUMMARY BACKGROUND DATA Surgical intervention has been the mainstay of treatment for infected peripancreatic fluid collections and abscesses. Increasingly, PCD has been used, with mixed results reported in the literature. METHODS A retrospective chart review of 1993 to 1997 was performed on 82 patients at a tertiary care public teaching hospital who had computed tomography-guided aspiration for suspected infected pancreatic fluid collection or abscess. Culture results, need for subsequent surgical intervention, length of stay, and death rate were assessed. RESULTS One hundred thirty-five aspirations were performed in 82 patients (57 male patients, 25 female patients) with a mean age of 40 years (range 17-68). The etiologies were alcohol (41), gallstones (32), and other (9). The mean number of Ransons criteria was four (range 0-9). All patients received antibiotics. Forty-eight patients had evidence of pancreatic necrosis on computed tomography scan. Cultures were negative in 40 patients and positive in 42. Twenty-five of the 42 culture-positive patients had PCD as primary therapy, and 6 required subsequent surgery. Eleven patients had primary surgical therapy, and five required subsequent surgery. Six patients were treated with only antibiotics. The death rates were 12% for culture-positive patients and 8% for the entire 82 patients. CONCLUSIONS Historically, patients with positive peripancreatic aspirate culture have required operation. This series reports an evolving strategy of reliance on catheter drainage. PCD should be considered as the initial therapy for culture-positive patients, with surgical intervention reserved for patients in whom treatment fails.

The role of anticoagulation in pylephlebitis

BACKGROUND Pylephlebitis may complicate any intra-abdominal infection and carries a high mortality rate. Acute cases are usually anticoagulated to prevent thrombus extension and enteric ischemia; however, the role of anticoagulation has not been clearly defined. METHODS Over a 3-year period, pylephlebitis was diagnosed in 44 patients with portal vein thrombosis on computed tomography scan with fever, leukocytosis, and/or positive blood cultures. The charts were reviewed for etiology, extent of venous thrombosis, and method and results of treatment. RESULTS Eighteen patients were hypercoagulable, due to clotting factor deficiencies (6), malignancy (8), or AIDS (4). Fifteen patients had mesenteric vein involvement. Thirty-two patients were not anticoagulated, and 5 died (3 with hypercoagulable states and 2 with normal clotting function). Twelve patients were anticoagulated, and none developed subsequent bowel infarction or died. CONCLUSION Patients with pylephlebitis and a hypercoagulable state due to neoplasms or clotting factor deficiencies should be anticoagulated. Patients with normal clotting function and mesenteric vein involvement may also benefit. We believe anticoagulation in patients with thrombus isolated to the portal vein and normal clotting function may be unnecessary.

Renal biopsy-related hemorrhage: frequency and comparison of CT and sonography

To evaluate the frequency of retroperitoneal hemorrhage related to renal biopsy, we prospectively assessed 182 patients (200 biopsies) using state-of-the-art CT and ultrasound. Our study revealed definite CT evidence of hemorrhage after 90.9% of biopsies. In a blinded analysis of images obtained in biopsied patients and in unbiopsied control patients the overall accuracy of CT was 93.8 versus 76.4% for ultrasound. Our data suggest that detectable hemorrhage is virtually always seen after renal biopsy and its frequency is much higher than noted in earlier studies.

The effects of chronic endoscopic variceal sclerotherapy on portal pressure in cirrhotics

The effect of obliterating esophageal varices by endoscopic sclerotherapy on portal pressure was prospectively studied in 11 cirrhotic patients with variceal hemorrhage. Portal venous pressure gradient, determined as the difference between transhepatic portal and hepatic vein pressure, increased by a mean of 31.1% +/- 14.5% in 8 (73%) and decreased by a mean of 30.1% +/- 11.7% in 3 (27%) patients, with no statistically significant change overall (P = 0.1). These changes in portal venous pressure gradient occurred despite an improvement in the laboratory and clinical parameters of hepatic function. Deep abdominal sonography with color flow imaging at variceal obliteration showed patent paraumbilical veins in 6 (55%) patients, 3 of whom had decreases in portal venous pressure gradient (29%, 19%, 42.5%) at variceal obliteration. In 5 (45%) patients without patent paraumbilical veins, a statistically significant increase in portal venous pressure gradient between initial endoscopic variceal sclerotherapy and variceal obliteration was noted (P = 0.008). Rebleeding (single episode in all 4 patients, before obliteration in 3 patients) occurred in those with an increase in portal venous pressure gradient; all patients with portal venous pressure gradient decreases were nonbleeders. No correlation between changes in portal venous pressure gradient and time to variceal obliteration, number of sclerotherapy treatments, or rebleeding episodes was observed. Thus, an increase in portal venous pressure gradient was noted in the majority of patients at variceal obliteration. Although the portal venous pressure gradient decrease may be explained by a patent paraumbilical vein, the mechanism of portal venous pressure gradient increase is not clear. It is speculated that this portal venous pressure gradient increase may be caused by an increase in collateral resistance or flow or a combination of both, resulting from obliteration of esophageal varices by endoscopic sclerotherapy.

Gray-Scale Ultrasonography of Hepatic Amoebic Abscesses

Retrospective analysis of the ultrasonograms of 42 hepatic amoebic abscesses in 34 patients was performed. All lesions were less echogenic than normal liver. All but 1 were contiguous with the liver capsule and had slight distal sonic enhancement. Twenty-three were predominantly homogeneous with fine, low-level echoes. This pattern is highly suggestive of hepatic amoebic abscess. Nineteen abscesses did not show this pattern and could not be diagnosed based on ultrasonographic criteria.

Gallbladder dysfunction in diabetes mellitus

To further elucidate the mechanism of impaired gallbladder emptying in diabetics with and without neuropathy, gallbladder function was assessed by ultrasonography following a medium-chain triglyceride (lipomul, 1.5 mg/kg) infusion into the duodenum and compared to that during intravenous infusion of cholecystokinin in diabetic women. Results were compared with five healthy control women. Mean (±sd) maximal percent gallbladder volume in diabetics following lipomul was reduced to 49±8% and after intravenous cholecystokinin to 47±9%, which was less than those in controls, 21±9% and 24±6%, respectively, but not significantly different. Further analysis of gallbladder emptying to lipomul differentiated two subgroups of diabetics: one subgroup (N=5) had emptying comparable to controls (responders), while the other (N=5) had very modest emptying (nonresponders). Two of the patients in the latter group had normal gallbladder emptying during exogenous cholecystokinin and their response would be compatible with visceral neuropathy. Blood levels of cholecystokinin, measured by bioassay, following lipomul and exogenous cholecystokinin were similar in controls and diabetics. Presence of diabetic neuropathy did not correlate with impaired gallbladder emptying. Follow up at 6 and 12 months of the three nonresponder diabetics revealed that no gallstones had developed and that two of them became responders to exogenous cholecystokinin. We conclude that: (1) following lipomul, about 50% of diabetics in this study have impaired gallbladder emptying, which is not strictly correlated with diabetic neuropathy; (2) this was not due to abnormal cholecystokinin release; (3) in diabetic patients with impaired gallbladder emptying another abnormality may be present in the gallbladder; and (4) impaired gallbladder contraction may not lead to gallstone formation in one-year follow-up.

Gray-scale and color flow sonography of pancreatic ductal adenocarcinoma

Current sonographic technology has enhanced imaging. This study analyzes the sonographic findings in a large series of patients with pancreatic ductal adenocarcinoma.

Spontaneous Rupture of Nonparasitic Cyst of the Liver

A case of spontaneous rupture of a nonparasitic liver cyst, documented by serial computed tomography scans, is reported. The patient was closely followed clinically after the rupture of the cyst and was treated conservatively, without surgical intervention. No peritonitis developed. This unusual complication of nonparasitic simple liver cysts may not always require surgery.

Color Comet-Tail Artifact: Clinical Applications

OBJECTIVE This article explores the circumstances under which the color comet-tail artifact occurs and illustrates the clinical value of the artifact. CONCLUSION Subtle abnormalities on gray-scale sonograms often are better appreciated and understood when the color comet-tail artifact is present. This artifact often is helpful in situations in which gray-scale imaging does not provide adequate information for a conclusive diagnosis. Visualization of the color comet-tail artifact can improve diagnostic confidence in a wide spectrum of clinical conditions encountered in sonographic practice.