ABSTRACT
PURPOSE: To measure the changes in wash-in and washout of contrast material on contrast material-enhanced computed tomographic (CT) scans in patients with adrenal adenomas and nonadenomas. MATERIALS AND METHODS: One hundred twenty-two patients with 135 adrenal masses (74 adenomas, 61 nonadenomas) underwent helical CT. Unenhanced CT was followed by enhanced CT at 30, 60, and 90 seconds and 3, 10, and 30 minutes. RESULTS: The adenomas enhanced significantly more than the nonadenomas at 60 seconds (P < .001), but the percentage enhancement of the adenomas was significantly greater than that of the nonadenomas at 30, 60, and 90 seconds (P < .001). At 3, 10, and 30 minutes, the absolute percentage loss of enhancement and the relative percentage loss of enhancement were significantly greater for the adenomas than for the nonadenomas (P < .001). Delayed enhanced CT at 10 minutes (sensitivity, 92%; specificity, 95%) and 30 minutes (sensitivity, 97%; specificity, 100%) was more accurate for differentiation of adenomas and nonadenomas than unenhanced CT (sensitivity, 82%; specificity, 95%). CONCLUSION: Adrenal adenomas exhibit greater washout of contrast material than do adrenal nonadenomas. The percentage change in washout of contrast material is a useful adjunct to absolute CT attenuation values in differentiation of adrenal adenomas and nonadenomas.
Subject(s)
Adenoma/diagnostic imaging , Adrenal Gland Neoplasms/diagnostic imaging , Contrast Media , Tomography, X-Ray Computed , Adenoma/pathology , Adolescent , Adrenal Gland Neoplasms/pathology , Adrenal Gland Neoplasms/secondary , Adult , Aged , Aged, 80 and over , Analysis of Variance , Biopsy , Carcinoma/diagnostic imaging , Carcinoma/pathology , Child , Contrast Media/administration & dosage , Contrast Media/pharmacokinetics , Female , Follow-Up Studies , Forecasting , Humans , Image Enhancement/methods , Image Processing, Computer-Assisted , Iohexol/administration & dosage , Iohexol/analogs & derivatives , Iohexol/pharmacokinetics , Male , Middle Aged , Predictive Value of Tests , Sensitivity and Specificity , Time Factors , Tomography, X-Ray Computed/methodsABSTRACT
Because of the anatomic localisation of the retroperitoneal space, the detection and elucidation of pathology in the retroperitoneum calls for clinical acumen and the utilisation of imaging techniques. During the past two decades, efforts spearheaded by the work of M. A. Meyers led to an enhanced understanding of retroperitoneal anatomy and pathology. Conventional radiographic techniques are often incapable of detecting and/or characterising retroperitoneal abnormalities. Sonography may be limited by patient-dependent-factors. CT is unaffected by bowel gas and provides discrete cross-sectional images of the organs, fascial planes and retroperitoneal compartments, making it an ideal tool for assessment of retroperitoneal disease. In clinically stable patients MRT may be a useful modality for providing helpful and additional information in characterising retroperitoneal abnormalities. In this review article the diagnostic possibilities of benign not organ-related diseases of the retroperitoneum are described. This is intended to give the reader an insight into the etiology and distribution patterns of retroperitoneal fluid and gas collections as well as into diagnosis and differential diagnosis of benign retroperitoneal diseases. The diagnostic impact of the different imaging modalities is discussed.
