Delayed imaging in routine CT examinations of the abdomen and pelvis: is it worth the additional cost of radiation and time?

OBJECTIVE: The purpose of this study was to retrospectively assess the potential benefits of delayed phase imaging series in routine CT scans of the abdomen and pelvis. MATERIALS AND METHODS: Routine contrast-enhanced abdominopelvic CT scans of 1000 consecutively examined patients (912 men, 88 women; average age, 60 years; range, 22-94 years) were retrospectively evaluated, and the added benefits of the delayed phase series through the abdomen were recorded for each examination. Examinations performed for indications requiring multiphasic imaging were excluded. Images were reviewed by two fellowship-trained abdominal radiologists, who were blinded to official CT reports. All examinations were performed between July 2008 and February 2010 at a single institution. Radiation doses for both the portal venous and delayed phases, when available, were analyzed to assess the effect of the delayed phase on overall radiation exposure. RESULTS: Forty-two patients (4.2%) had findings that were further characterized or were observed only in the delayed phase. Most were incidental findings that could have been confirmed at noninvasive follow-up imaging, such as sonography or unenhanced CT or MRI. The most common findings were liver hemangioma (n = 12), adrenal adenoma (n = 12), and parapelvic renal cysts (n = 6). The most important finding was detection of a renal mass in one patient (0.1%). The mass was seen only on the delayed phase images but was difficult to appreciate in the portal venous phase. In the other 958 patients (95.8%), delayed imaging was of no benefit. In addition, use of the delayed phase resulted in a mean 59.5% increase in effective radiation dose. CONCLUSION: An additional delayed phase through the abdomen in routine contrast-enhanced CT examinations of the abdomen and pelvis is of low yield, particularly if reliable follow-up imaging to further elucidate uncertain findings is available.

Recurrent non-surgical pneumoperitoneum due to jejunal diverticulosis.

BACKGROUND: The presence of free intraperitoneal gas usually warrants emergent surgery. In rare instances, however, non-surgical conditions such as jejunal diverticulosis can cause pneumoperitoneum and do not require intervention. OBJECTIVES: The objective of this article is to provide the computed tomography (CT) scan findings of jejunal diverticulosis causing pneumoperitoneum. The article will also discuss other non-surgical causes of spontaneous pneumoperitoneum to increase awareness and avoid unnecessary surgery. CASE REPORT: We describe a case of recurrent pneumoperitoneum due to jejunal diverticulosis in which the patient remained asymptomatic and free of complications with repeated evaluations in the emergency department over the course of 18 months. CONCLUSION: Although spontaneous pneumoperitoneum due to jejunal diverticulosis is a rare finding, when it does occur, this condition must be distinguished from other forms of pneumoperitoneum to avoid unnecessary surgery. CT scan findings of multiple rounded, variably sized jejunal outpouchings filled with oral contrast are helpful in diagnosing jejunal diverticulosis and confirming the decision for conservative management of the patient.

MR imaging of scrotal tumors and pseudotumors.

Magnetic resonance (MR) imaging is an important imaging technique in the evaluation of scrotal masses, providing a useful adjunct to ultrasonography (US). Although US is the modality of choice for initial evaluation of scrotal pathologic conditions because of its wide availability, low cost, and high sensitivity for detection of testicular and paratesticular disease processes, US findings may occasionally be inconclusive. MR imaging may provide additional information in these cases, often affecting patient management. This article reviews and illustrates the MR imaging features of solid extratesticular and intratesticular benign and malignant scrotal tumors, as well as nonneoplastic lesions that can mimic neoplasia. Normal scrotal MR anatomic features and optimal MR imaging technique are also presented.

Fatty liver disease: MR imaging techniques for the detection and quantification of liver steatosis.

Fatty liver disease is the most common cause of chronic liver disease in the United States. Noninvasive detection and quantification of fat is becoming more and more important clinically, due in large part to the growing prevalence of nonalcoholic fatty liver disease. Steatosis, the accumulation of fat-containing vacuoles within hepatocytes, is a key histologic feature of fatty liver disease. Liver biopsy, the current standard of reference for the assessment of steatosis, is invasive, has sampling errors, and is not appropriate in some settings. Several magnetic resonance (MR) imaging-based techniques--including chemical shift imaging, frequency-selective imaging, and MR spectroscopy--are currently in clinical use for the detection and quantification of fat-water admixtures, with each technique having important advantages, disadvantages, and limitations. These techniques permit the breakdown of the net MR signal into fat and water signal components, allowing the quantification of fat in liver tissue, and are increasingly being used in the diagnosis, treatment, and follow-up of fatty liver disease.