Magnetic Resonance Imaging and the Use in Small Renal Masses

Abstract

The incidence of small renal masses (SRM) has been increasing, and this is mainly attributed to the incidental finding of such masses on imaging performed in asymptomatic patients. Consequently, this calls for careful evaluation and management of these masses to determine their nature and need for treatment. This article reviews current literature regarding the evaluation and management of SRM. It focuses on the specific use of MRI in the diagnosis and management of SRM. A Medline review of the literature was performed from 1996 to the present time. Computed tomography (CT) imaging has been the investigation of choice for evaluating SRM. However, some remain difficult to determine their malignant or benign nature and remain indeterminate. In such cases, further imaging with magnetic resonance imaging (MRI) can be performed to evaluate the mass in more detail. It can also be used where CT is contraindicated and where active surveillance is the treatment of choice and radiation exposure is a concern. MRI is a useful tool in evaluating an indeterminate small renal mass. Accurate diagnosis and management of SRM require close collaboration between a urologist and radiologist to identify potentially malignant tumours to subsequently reduce mortality from renal cell cancer.

Comparison of contrast-enhanced ultrasound with MRI in the diagnosis of complex cystic renal masses: a meta-analysis

“…Similarly, MRI can also result in the upgrade of renal cysts when using the Bosniak classification system due to excellent detection for the number of enhanced solid components (29,30). Andrew et al (31) performed a retrospective study, and the results revealed that it is easier to upgrade cyst complexity when using the Bosniak classification at the field strength of 3.0-T than 1.5-T.…”

“…Similarly, MRI can also result in the upgrade of renal cysts when using the Bosniak classification system due to excellent detection for the number of enhanced solid components (29,30). Andrew et al.…”

“…However, defects in subtraction imaging may be the interference of the addictive noise, which can add the difficulty to observe the true internal enhancement in tumors (33). Some studies have proved the value of MRI in evaluating an equivocal small renal mass (29), and new sequences with high-resolution free-breathing three-dimensional fat-suppressed T1 gradient echo can make minor enhancement in small cystic renal masses easier to be detected (34). Some benign neoplasm such as angiomyolipoma with epithelial cysts (AMLEC), a rare subtype of angiomyolipoma, is very easy to be misdiagnosed as renal cell carcinoma, and the dual gradient-echo imaging may have the capability to detect small amount of fat in AMLEC to avoid the misdiagnosis (35).…”

Renal, pelvic and mesenteric tumors with low signal intensity on T2-weighted MR image: A review

“…Sixty-seven percent of renal tumors have also been described as possessing a high possibility of malignancy. Renal tumors can be significantly differentiated using MR images to distinguish between malignant and nonmalignant tumors (3). Necrosis is among the factors that contribute to the generation of low intensity on T2-weighted MR images.…”