CT appearance of direct leukemic invasion of bowel.

Although leukemic invasion of bowel is frequently seen on pathologic examination, it has rarely been described in the imaging literature. Previous radiographic reports have relied mostly on non-cross-sectional imaging techniques such as barium enema and have detected abnormalities only in the most advanced stages of disease when prognosis is uniformly poor. We describe a case of direct leukemic invasion seen on computed tomography which may offer the advantage of earlier detection and more favorable prognosis.

Pelvic computed tomography of breast carcinoma patients. Should it routinely be added to abdominal computed tomography?

BACKGROUND: This study was conducted to determine if pelvic computed tomography (CT) should routinely be appended to abdominal CT in the workup of patients with breast carcinoma. METHODS: The abdominal-pelvic CTs of 139 breast carcinoma patients (195 exams) were reviewed. Scans were grouped by indication and whether pelvic pathology was known before CT. Pelvic CT results were correlated with their effect on patient management. RESULTS: Among the 119 patients without pre-CT evidence of pelvic disease, a nonosseous pelvic metastasis was identified in only 1; this patient also had liver metastases and management was not changed. No unsuspected pelvic CT finding altered therapy for breast carcinoma. However, three patients underwent surgery for asymptomatic masses discovered on pelvic CT; all were benign. CONCLUSIONS: Pelvic CT is unlikely to affect the management of patients with breast carcinoma by detecting occult metastatic disease.

Value of CT in localizing site of gastrointestinal hemorrhage following negative angiography.

This case report of severe gastrointestinal (GI) bleeding demonstrates the utility of computed tomography (CT) in localizing such hemorrhages when all other diagnostic modalities have been exhausted. All previous studies in this case were nondiagnostic. However, abdominal CT performed without the benefit of oral contrast but immediately following negative angiography was useful in directing the surgeon to the region of hemorrhage by documenting the presence of focally dense intraluminal contrast within the small bowel loops.

Metastasis or adenoma? Computed tomographic evaluation of the adrenal mass.

BACKGROUND: Determining the nature of an adrenal mass is often a clinical challenge. OBJECTIVE: To determine if unenhanced computed tomographic (CT) scanning can differentiate benign adenomas from metastases. METHODS: Twenty-four pathologically proven adrenal masses were retrospectively correlated with their appearance on unenhanced CT scanning. RESULTS: Metastases were significantly larger than adenomas and had higher attenuation coefficients. A sensitivity-to-specificity ratio of 33:100 was achieved at a threshold of 0 Hounsfield units (HU), while a threshold of 10 HU produced a ratio of 58:92. A threshold size of 2.5 cm produced a ratio of 58:100. Attenuation and size were the only useful criteria for differentiating adenomas from metastases. CONCLUSION: Measuring the size and attenuation of adrenal masses can help identify benign adenomas. Lesions exceeding specific thresholds may still be benign and may require biopsy. We advocate documenting lesion stability for longer than is usually done, as one metastatic lesion remained without significant change in appearance for 18 months.

Hypoechoic renal pyramids: sonographic visualization in older children and young adults.

The frequency and degree of visualization of medullary pyramids in a normal population, aged 10-29 years, was analyzed. Hypoechoic pyramids were visualized in 42% of right kidneys in subjects aged 10-18 years and in 27% of subjects aged 19-29 years. Prominently hypoechoic pyramids, mimicking the appearance of neonatal kidneys, were seen in an additional 34% of subjects aged 10-18 years and in 16% aged 19-29 years. Prominent pyramids were present in 50% of subjects with renal cortical echogenicity (RCE) equal to liver, but also in 21% of subjects with RCE less than liver. Our study expands the age at which prominently hypoechoic medullary pyramids can be considered a normal finding. This may relate to recent improvements in ultrasound technology.

Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy.

All testicular sonograms performed over a 2.5-year period were retrospectively reviewed, yielding eight patients with pathologically proven lesions consisting primarily of tubular sclerosis and interstitial fibrosis. Only two patients (25%) had a palpable abnormality. A variety of sonographic patterns was found, including focal hypoechoic or hyperechoic lesions and diffuse heterogeneity of the testicular parenchyma. The clinical and sonographic findings prompted open biopsy or orchiectomy in all cases. In the same time period, nine pathologically proven testicular malignancies were evaluated sonographically and displayed either well-defined hypoechoic or diffusely heterogeneous echo patterns. All but two of these patients (78%) had palpable abnormalities. This study demonstrates a significant overlap in the sonographic appearance of benign fibrotic lesions and testicular malignancies. When careful palpation of a sonographically heterogeneous or focal hypoechoic lesion fails to reveal a mass and serum tumor markers are negative, an open biopsy with frozen section analysis should be considered rather than proceeding directly to orchiectomy. Homogeneously hyperechoic masses can be considered benign and do not require surgery.

Comparison of iohexol-240 versus iohexol-300 in abdominal CT.

Forty patients without evidence of liver, kidney, or significant cardiac disease were prospectively divided into two groups of 20, receiving either iohexol-240 or iohexol-300. A contrast load of 150 ml was administered in conjunction with a rapid scanning technique at a preselected, fixed level to include liver, renal cortex, and aorta. Peak enhancement was calculated as change in Hounsfield units (HU) over baseline for each area of interest. Mean peak enhancement and standard deviation were calculated for each organ, and the difference between the means for the two contrast agents was compared using the Student's t test. Differences were not statistically significant with all p values greater than 0.05. Our results suggest iohexol-240 is preferred to iohexol-300 for body computed tomography (CT) due to its lower cost and iodine load without statistically significant change in diagnostic quality of the examination.

Abdominal lymphadenopathy: spectrum of CT findings.

Many malignant processes cause abdominal lymphadenopathy, and computed tomography (CT) has become the primary modality for its detection. Diagnosis of lymphadenopathy is facilitated by optimal imaging techniques and a knowledge of the various nodal chains, their complex interconnections, and preferential pathways of spread. Optimal techniques include imaging after oral administration of adequate amounts of barium suspension and dynamic scanning after intravenous administration of contrast material with an infusion pump. Although such techniques help prevent misdiagnoses due to normal and anomalous vascular structures, other benign diseases can mimic the CT appearance of malignant lymphadenopathy. The authors emphasize a regional approach for the diagnosis of lymphadenopathy, according to the groupings of retrocrural, retroperitoneal, gastrohepatic ligament, porta hepatis, celiac and superior mesenteric artery, pancreaticoduodenal, perisplenic, mesenteric, and pelvic lymph nodes. Lymphadenopathy is defined as retrocrural nodes greater than 6 mm in short axis, upper abdominal nodes greater than 10 mm, and pelvic nodes greater than 15 mm.