Small (<2-cm) upper-tract urothelial carcinoma: Evaluation with gadolinium-enhanced three-dimensional spoiled gradient-recalled echo MR urography

Purpose: To retrospectively evaluate the detection of small (<2-cm) urothelial tumors by using gadolinium-enhanced three-dimensional (3D) spoiled gradient-recalled echo (GRE) magnetic resonance (MR) urography. Materials and Methods: This HIPAA-compliant study received institutional review board approval. All patients included had previously consented to the use of their medical records for research purposes. Eleven of 110 patients (10 men, one woman; mean age, 73.5 years) who underwent MR urography were ultimately identified to have 23 upper-tract urothelial carcinomas smaller than 2 cm or carcinoma in situ. Breath-hold coronal T2-weighted single-shot fast spinecho and breath-hold coronal 3D T1-weighted spoiled GRE images with fat suppression during nephrographic and excretory phases after intravenous injection of gadolinium-based contrast material were obtained in all patients with a 1.5-T imager. Two radiologists reviewed the MR images in consensus for the presence of tumors. Lesion detectability was compared between each sequence by using the McNemar test. Results: Of 23 tumors, 17 (74%) were detected by using at least one sequence, eight (35%) were detected with T2-weighted imaging, 15 (65%) were detected on nephrographic phase images, and 15 (65%) were detected on excretory phase images. Two lesions each were detected only on either nephrographic or excretory phase images. Detectability was significantly higher on nephrographic and excretory phase images compared with T2-weighted images (P < .05). Conclusion: Gadolinium-enhanced 3D spoiled GRE MR urography helped detect 74% of small urothelial carcinomas. Nephrographic and excretory phase images are essential for helping detect small urothelial carcinomas.