Purpose: To compare a noncontrast enhanced balanced steady state free precession (bSSFP) MRI technique with a conventional dynamic contrast-enhanced (DCE) threedimensional (3D) spoiled gradient recalled echo (SPGR) imaging in the vascular staging of renal and adrenal malignancies.
Materials and Methods:Sixty-three MRIs with both bSSFP and DCE acquisitions performed for initial staging of renal and adrenal malignancies were retrospectively evaluated for presence and extent of thrombus in the renal veins and inferior vena cava (IVC). Thrombus characterization was also evaluated. DCE imaging was used as the standard-of-reference. Histopathology was available in 46 of 63 cases as an additional external standard.Results: There is very good agreement between bSSFP and DCE imaging for determining the presence or absence of thrombus in the renal veins (r ¼ 0.95; P < 0.0001) and IVC (r ¼ 0.91; P < 0.0001). BSSFP is less successful at distinguishing bland from tumor thrombus.
Conclusion:Noncontrast enhanced bSSFP is an acceptable alternative to DCE imaging for vascular staging of locally advanced renal/adrenal malignancies, with somewhat limited ability to distinguish bland from tumor thrombus. STAGING OF LOCALLY advanced renal and adrenal malignancies which includes determination of the extent of venous invasion can have significant implications in surgical management and prognosis (1). Dynamic contrast-enhanced (DCE) CT and MRI share similar overall staging accuracy (2), although MRI has been found to be slightly more accurate in assessment of thrombus extension into the inferior vena cava (IVC) (3-5). While MRI (and CT) staging examinations are typically performed with contrast agents, gadolinium agents are relatively contraindicated in a small but substantial percentage of patients, namely those who are pregnant, are on dialysis, or have severely impaired renal function. In these cases, noncontrast enhanced (NCE) MRI techniques may offer a useful alternative.Long-standing NCE MR venography (MRV) techniques such as two-dimensional (2D) time-of-flight are limited in the abdomen by long acquisition times, motion artifact, and insensitivity to in-plane flow. An alternative NCE bright-blood MRV technique, frequently used in cardiac MRI and noncontrast MR angiography is balanced steady state free precession (bSSFP). 2D bSSFP (6-8) images demonstrate T2/T1 weighting with high signal-to-noise ratio (SNR), and can be obtained with rapid sequential acquisition, fat suppression, and overlapping thin sections. This technique is particularly appealing for evaluating veins in the abdomen and pelvis (7,9-11). Potential limitations include banding artifacts particularly near the edges of the field of view.We retrospectively evaluated the accuracy of vascular staging using NCE 2D fat-saturated bSSFP in comparison to conventional DCE MRI in a series of patients undergoing clinical MRI for staging of renal and adrenal malignancies.
MATERIALS AND METHODS
PatientsA retrospective review was performed following approval by the Institutional...