Antonio C. Gonzalez

The Transjugular Technique of Hepatic Venography and Biopsy, Cholangiography, and Obliteration of Esophageal Varices

The transjugular technique facilitates various diagnostic and therapeutic procedures in the liver. Even in patients with defective hemostasis, severe ascites, or marked obesity, liver biopsy or cholangiography can be performed with relative safety. It also provides an alternative route for entry into the portal system.

Preoperative diagnosis of pancreatic carcinoma by percutaneous aspiration biopsy.

Carcinoma of the pancreas and chronic pancreatitis may be extremely difficult to differentiate by standard diagnostic methods preoperatively as well as at the operating table. Operative pancreatic biopsy may have a high morbidity, rare mortality, and can be misleading. Percutaneous aspiration biopsy may be of great potential benefit. It provides additional histological material not usually available, and an accurate diagnosis of malignancy can be made. In select patients a needless laparotomy may be avoided. It appears to be a safe procedure that should be considered in the evaluation of the patient with suspected pancreatic malignancy in which a mass lesion is demonstrated by ultrasonography, computerized tomography, angiography, or retrograde pancreatography.

Ultrasonic examination of the gallbladder: A review

Ultrasonography is a helpful, non-invasive, and relatively inexpensive adjuvant to oral cholecystography for evaluating the gallbladder and its diseases. This method can be highly accurate in detecting gallstones and is specially useful when there is non-visualisation in radiographic contrast studies. Various ultrasound patterns of gallstones are described. All these patterns should demonstrate a sonic shadow in association with an intraluminal defect. Sonography is particularly useful in demonstrating cholelithiasis and organ dilatation in suspected acute cholecystitis. In addition to gallbladder disease, this technique simultaneously offers pertinent anatomical information about the porta hepatis. This information would otherwise require additional diagnostic investigation. Because, in many instances, sonography is non-specific, or blind to certain gallbladder non-calculous filling defects, and because of present lack of uniform standard quality control methods for performing this procedure, it should be considered only as a complementary, imaging procedure to oral cholecystography.

Derivation and Validation of a CT Scan Scoring System for Discriminating Malignant From Benign Pleural Effusions

BACKGROUND Chest CT scanning has become an integral part of the workup for undiagnosed pleural effusions. We aimed to develop a CT scan-based scoring system for differentiating between benign and malignant pleural effusions. METHODS A number of chest CT scan abnormalities were compared between 228 patients with benign and 115 with malignant effusions (derivation cohort). A logistic regression analysis was used to identify the independent predictors of malignancy and generate CT scan scores, with more points assigned to those findings associated with higher β-coefficient values. The diagnostic accuracy of the CT scan scoring system was calculated for the derivation cohort and further evaluated in two independent populations (n = 80 and 42, respectively) by two radiologists. RESULTS CT scan scores predicting malignancy included any pleural lesion (ie, nodule, mass, or thickening) ≥ 1 cm (5 points); the presence of liver metastases, an abdominal mass, or a lung mass or nodule ≥ 1 cm (3 points each); and the absence of either pleural loculations, pericardial effusions, or cardiomegaly (2 points each). In the first validation cohort, a sum score of ≥ 7 yielded a sensitivity of 88% (95% CI, 73%-95%), specificity of 94% (95% CI, 83%-98%), likelihood ratio positive of 13.8 (95% CI, 4.6-41.5), likelihood ratio negative of 0.13 (95% CI, 0.05-0.33), and area under the receiver operating characteristics curve of 0.919 (95% CI, 0.849-0.990). Moreover, 69% of 42 patients with pathologically unconfirmed malignant effusions from a second independent cohort would have been correctly labeled by the predictive score. CONCLUSIONS A simple CT scan-based scoring system can help physicians to separate malignant from benign pleural effusions.

Ultrasonographic Evaluation of Vascular Access Complications

In 24 patients, sonograms were obtained of 25 vascular accesses, 16 of which were bovine grafts, 7 arteriovenous fistulae, 1 a polytetrafluoroethylene graft, and 1 an external Silastic shunt. On the sonograms, the lumen, course, and insertions of the vascular grafts and fistulae were outlined, anterior and posterior aneurysms demonstrated, hematomas differentiated from aneurysms, and intrinsic distinguished from extrinsic lesions. The authors conclude ultrasonography is a valuable adjunct to clinical evaluation in assessing certain complications of vascular access.

Megalocytic interstitial nephritis: ultrasonic and radiographic changes.

The radiologic and ultrasonic findings are presented in a case of megalocytic interstitial nephritis, a very rare condition, in many ways similar to renal malacoplakia. The role of ultrasound in the interpretation of the radiographic changes is discussed. Excretory urography will demonstrate a nonspecific renal mass effect and angiography may rule out evidence of tumor. Ultrasonic correlation can be highly suggestive of an interstitial parenchymal lesion.

Ultrasound Evaluation of Vascular Access Used in Hemodialysis

The purpose of this study is to develop and perfect a method to examine and follow-up vascular access by a non-invasive technique. Ultrasonographically appears as the ideal approach to this problem. High-frequency, short focused transducers in combination with improven signal processing and display considerably enhance the feasibility of study. Like superficially located vascular structures, bovine grafts and cannular arteriovenous shunts can be easily demonstrated sonographically. We report our preliminary experience with 24 cases. We plan to base our final results on a minimum of 100 cases, hopefully with occasinal radiographic documentation.