Robert A. Halvorsen

CT appearance of adrenal cortical carcinoma

The computed tomographic (CT) findings in eight patients with proven primary adrenal cortical carcinoma are presented. The tumors ranged in size from 9 to 22 cm in diameter and all exhibited central necrosis. Contrast enhancement was irregular in all cases and associated tumor calcification was present in three cases. The CT appearance of a huge adrenal mass with central necrosis is typical of adrenal cortical carcinoma hut can occasionally he seen with pheochromocytoma or a large metastasis to the adrenal gland.

Safety Considerations in the Power Injection of Contrast Media Via Central Venous Catheters during Computed Tomographic Examinations

RATIONALE AND OBJECTIVES.This study addresses the theoretical, experimental, and clinical application of using a central venous catheter system (CVS) for the rapid injection of contrast media during computed tomography (CT). METHODS.Application of Poiseuilles law and the Reynolds equation yielded theoretical data. In-line pressures were measured in experimental models and patients undergoing CT. Diatrizoate meglumine and iohexal contrast media were evaluated. RESULTS.The Reynolds number was consistent with laminar flow, allowing the application of Poiseuilles law. The calculated and experimental catheter tubing-chamber connection pressures were safe for both contrast media, at rates of 1 mL/second for long catheter tubing and 2 mL/second for short tubing. Thirteen patients had measured pressures within safety limits with no complications. CONCLUSIONS.This study establishes that power injection of contrast media via a CVS during CT is a safe procedure. Benefits include no need for peripheral intravenous catheter placement, decreased paramedical staff radiation exposure, and improved CT image quality.

Congenital Anomalies and Normal Variants of the Pancreaticobiliary Tract and the Pancreas in Adults: Part 2, Pancreatic Duct and Pancreas

OBJECTIVE The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the pancreatic duct and the pancreas using contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT. CONCLUSION Congenital anomalies and normal variants of the pancreatic duct and the pancreas may be clinically significant and may create a diagnostic challenge. Recognition of the updated imaging features of these entities is important in clinical management and for avoiding misdiagnosis.

Computed tomographic staging of gastrointestinal tract malignancies. Part I. Esophagus and stomach.

The utility and limitations of CT staging of carcinomas of the esophagus, stomach, small bowel, and colon are reviewed. Routine preoperative staging of esophageal carcinoma is recommended because of CTs sensitivity of more than 90% in detecting mediastinal invasion and a specificity of more than 85% in collected series. We recommend the use of CT as a problem-solving technique rather than as a routine preoperative test in patients with gastroesophageal junction, and gastric and small bowel malignancies. Routine use of CT to stage colorectal carcinomas also does not seem justifiable, due to the inability of CT to determine the depth of bowel wall involvement and to detect tumor in normal size lymph nodes. CT can help differentiate tumors that invade the pelvic side walls from more limited cancers and, therefore, in certain cases can aid in therapy planning. CT is the best method for detecting local recurrence in patients with rectosigmoid carcinomas.

Congenital anomalies and normal variants of the pancreaticobiliary tract and the pancreas in adults: part 1, Biliary tract.

OBJECTIVE The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the biliary tract with contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT. CONCLUSION Recognizing findings of congenital anomalies and normal variants of the biliary tract at MRCP, MRI, and helical CT, and knowledge of the clinical significance of each entity, are important for establishing a correct diagnosis and in guiding appropriate clinical management.

Sonography of small renal masses with indeterminant density characteristics on computed tomography

Nine small renal masses with attenuation coefficients greater than 20 HU on computed tomography (CT) were termed indeterminate for cyst or renal cell carcinoma. Correlative sonography identified the fluid-filled internal architecture in four of five cysts and correctly characterized as solid four small renal cell carcinomas. The sonogram was particularly valuable in assessing masses that were indeterminate on CT when enhancement was equivocal or when intravenous contrast could not be administered. We conclude that sonography is extremely useful as a noninvasive procedure in evaluating the occasional small renal mass with CT number greater than 20 HU.

THE USE OF IOHEXOL IN PATIENTS WITH PREVIOUS REACTIONS TO IONIC CONTRAST MATERIAL : A MULTICENTER CLINICAL TRIAL

Patients who have had prior reactions to iodinated contrast material have increased risk for repeat reactions. Nonionic contrast agents have been reported to reduce the risk of contrast reactions. A multicenter study was undertaken to determine the repeat reaction rate using iohexol. Two hundred ninety-one repeat reactors were included in the study, of whom one-third received premedication. Sixteen patients (5.5%) experienced repeat reactions; none was severe, and only one was more serious than the prior reaction. This is in contrast to the reported 16% to 44% repeated reaction rate for ionic agents. We conclude that iohexol is effective in reducing the occurrence of repeat reactions from the level observed with ionic agents without premedication. Iohexol appears to be as effective as ionic agents plus premedication in this high-risk group of patients.

Frequency and Importance of Small Amount of Isolated Pelvic Free Fluid Detected with Multidetector CT in Male Patients with Blunt Trauma

PURPOSE To retrospectively determine the frequency and importance of a small amount of isolated pelvic free fluid seen at multidetector computed tomography (CT) in male patients who have blunt trauma without an identifiable cause. MATERIALS AND METHODS Institutional review board approval was obtained, and the requirement for informed consent was waived for this HIPAA-compliant study. One thousand male patients with blunt trauma who underwent abdominopelvic CT at a level 1 trauma center between January 2004 and June 2006 were entered into this study. The CT images of the 1000 patients were reviewed independently by two abdominal radiologists. CT scan assessment included evaluation for presence or absence of pelvic free fluid, any traumatic or nontraumatic cause of the free fluid, pelvic free fluid attenuation and volume measurements, and determination of the location of pelvic free fluid. Interobserver agreement was determined with kappa statistics, and the Student t test was used to assess differences in the mean volume and mean attenuation of the pelvic free fluid in the patients with and those without injury. RESULTS Pelvic free fluid was identified in 10.2% (102 of 1000) of patients. A small amount of isolated pelvic free fluid without any identifiable cause was identified in 4.8% (48 of 1000) of patients by reader 1 and in 5.0% (50 of 1000) of patients by reader 2 (kappa value, 0.76) and was located at or below the level of the third sacral vertebral body in all 49 patients with isolated pelvic free fluid. The mean volume and mean attenuation of the small amount of isolated pelvic free fluid were 2.3 mL +/- 1.5 (standard deviation) and 8.1 HU +/- 3.9, respectively. None of the patients in this group had an undiagnosed bowel and/or mesenteric injury. CONCLUSION In male patients with blunt trauma, a small amount of isolated pelvic free fluid with attenuation equal to that of simple fluid and located in the deep region of the pelvis likely is not a sign of bowel and/or mesenteric injury.

Computed Tomography of Masses in Periportal/hepatoduodenal Ligament

The CT findings in 70 patients with masses in or adjacent to the porta hepatis/hepatoduodenal ligament were analyzed. Underlying disease processes included metastatic disease (44 cases), lymphoma/leukemia (10 cases), biliary carcinoma (seven cases), hepatoma (four cases), benign disease (three cases), and gallbladder carcinoma (two cases). Location of the mass was confirmed in 62 patients and showed six patterns: four along the hepatoduodenal ligament or within the porta hepatis: another within the liver impinging on the hepatoduodenal ligament/porta hepatis: the sixth, an intraductal mass. Of the masses along the hepatoduodenal ligament or within the porta hepatis the four patterns were (a) well defined nodular masses caused by discrete nodes: (b) matted masses due to confluent adenopathy: (c) mixed, well defined and confluent masses in various locations along the hepatoduodenal ligament: (d) infiltrating, enhancing soft tissue densities obscuring the portal vein margins. No disease specific pattern was seen; nonetheless, knowledge of these patterns is very helpful in detection of masses in this region.

Echocardiographic detection of perforation of the cardiac ventricular septum by a permanent pacemaker lead

Abstract Previously reported complications of temporary transvenous pacing include perforation of the ventricular septum or ventricular wall. 1–4 Perforation of the ventricular septum by a permanent pacing electrode with long-term left ventricular pacing has not been reported.