Direct coronal and direct sagittal CT of abdomen and pelvis: an approach to staging malignancies.

Direct coronal and sagittal CT images are of high quality and are applicable to a majority of patients in daily practice. Because of the fact that transverse scans alone can be misleading, direct CT images in two or more different planes greatly enhance one's capability to stage neoplasms that are complex and extensive. The integrity of the margins of an organ, in the presence of tumor, is best determined by coronal or sagittal scanning. Lesions of the adrenal and kidney and retroperitoneal processes with possible extension into liver or other adjacent organs can be evaluated best using the combination of transverse and coronal or sagittal scans of the upper abdomen. Depending on the origin of pelvic lesions, the radiologist must consider in every individual case the performance of either direct coronal or sagittal sections or both. This judgment is based on the findings on the transverse scans, understanding of anatomic relationships of the pelvic viscera and knowledge of staging systems and their implications with respect to therapeutic decisions. In such a tailored approach, multiplanar CT facilitates improved presurgical evaluation. In some cases, the true extent of the lesion can only be seen in the coronal or sagittal planes. A potential new role for direct multiplanar CT is that it may be used as a sort of "gold standard" for the analysis of multiplanar ultrasound and MRI studies.