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[Errors of magnetic resonance in the diagnosis of small renal tumors]
L Del Viscovo1, F Ginolfi, A Rotondo
1Istituto di Scienze Radiologiche (II Cattedra), Facoltà di Medicina e Chirurgia, Università degli studi di Napoli Federico II.
Abstract:
MR examinations were performed on 16 patients with small (< 35 mm diameter) solid renal tumors previously diagnosed with US and/or CT. The study was aimed at assessing MR accuracy in the identification and characterization of this type of lesion. The studies were performed with a 0.5 T GE MR Max Plus unit, with no paramagnetic contrast medium administration. MRI detected the lesion in 15 cases (93.7%). In 3/15 patients (18.7%) the tumors had signal patterns similar to those of simple renal cysts--i.e., homogeneously hypointense on T1 and markedly hyperintense on T2-weighted images. In one patient (6.2%) MRI failed to detect the lesion. In the extant 12 cases the tumors were correctly demonstrated but had different signal patterns. On T1-weighted images 6 lesions were hypointense, 2 hyperintense because of hemorrhagic content, and 4 exhibited poor contrast with the surrounding renal parenchyma. On T2-weighted images 4 lesions were inhomogeneously hyperintense, 3 were hypointense because of fibrosis or old blood content, and in 5 cases contrast between the tumor and the renal parenchyma was poor. The authors conclude that T1-weighted MR images, in a midfield MR unit, are more sensitive than T2-weighted images in identifying small renal tumors. MRI is less accurate in the evaluation of these lesions than CT and US. In particular, since small renal lesions may be misdiagnosed as simple cysts, the use of other imaging modalities--e.g., US and CT--is recommended if a renal cyst is first identified on MR images.
Insights
Magnetic Resonance Imaging (MRI) can identify most small solid renal tumors, but T1-weighted images are more sensitive than T2-weighted images. However, MRI is less accurate than ultrasound (US) and computed tomography (CT) for characterizing these lesions.
Area of Science:
- Radiology and Imaging Science
- Medical Diagnostics
Context:
- Small solid renal tumors (< 35 mm diameter) pose diagnostic challenges.
- Previous diagnosis often relies on ultrasound (US) and computed tomography (CT).
Purpose:
- To assess the accuracy of Magnetic Resonance Imaging (MRI) in identifying and characterizing small solid renal tumors.
- To compare the sensitivity of T1-weighted versus T2-weighted MRI sequences for small renal lesions.
Summary:
- MRI detected 93.7% of small solid renal tumors, with T1-weighted images showing higher sensitivity than T2-weighted images.
- 18.7% of tumors mimicked simple renal cysts on MRI, and overall MRI accuracy was lower than US and CT.
- Poor contrast with renal parenchyma was noted in some cases on both T1 and T2-weighted images.
Impact:
- Highlights the potential for misdiagnosis of small renal tumors as simple cysts on MRI.
- Recommends the use of complementary imaging modalities like US and CT for definitive diagnosis.
- Suggests T1-weighted MRI sequences are more effective for initial detection of small renal masses.