Utility and limitations of 3-Tesla diffusion-weighted magnetic resonance imaging for differentiation of renal tumors.
OBJECTIVE
To investigate utility and limitations of 3-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiation of benign versus malignant renal lesions and renal cell carcinoma (RCC) subtypes.


METHODS
Sixty patients with 71 renal lesions underwent 3 Tesla DW-MRI of the kidney before diagnostic tissue confirmation. The images were retrospectively evaluated blinded to histology. Single-shot echo-planar imaging was used as the DW imaging technique. Apparent diffusion coefficient (ADC) values were measured and compared with histopathological characteristics.


RESULTS
There were 54 malignant and 17 benign lesions, 46 lesions being small renal masses ≤ 4 cm. Papillary RCC lesions had lower ADC values (p=0.029) than other RCC subtypes (clear cell or chromophobe). Diagnostic accuracy of DW-MRI for differentiation of papillary from non-papillary RCC was 70.3% resulting in a sensitivity and specificity of 64.3% (95% CI, 35.1-87.2) and 77.1 (95% CI, 59.9-89.6%). Accuracy increased to 83.7% in small renal masses (≤ 4 cm diameter) and sensitivity and specificity were 75.0% and 88.5%, respectively. The ADC values did not differ significantly between benign and malignant renal lesions (p=0.45).


CONCLUSIONS
DW-MRI seems to distinguish between papillary and other subtypes of RCCs especially in small renal masses but could not differentiate between benign and malignant renal lesions. Therefore, the use of DW-MRI for preoperative differentiation of renal lesions is limited.
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: sabina.sevcenco@meduniwien.ac.at.
S
S
Sevcenco
Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: gertraud.heinz-peer@meduniwien.ac.at.
G
G
Heinz-Peer
Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: lothar.ponhold@meduniwien.ac.at.
L
L
Ponhold
Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: domagoj.javor@meduniwien.ac.at.
D
D
Javor
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: frenklin.kuehhas@meduniwien.ac.at.
F E
FE
Kuehhas
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: christoph.klingler@meduniwien.ac.at.
H C
HC
Klingler
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: mesut.remzi@gmx.at.
M
M
Remzi
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: peter.weibl@meduniwien.ac.at.
P
P
Weibl
Medical University of Vienna, Dept. of Urology, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: sfshariat@gmail.com.
S F
SF
Shariat
Medical University of Vienna, Dept. of Biomedical Imaging and Image-guided Therapy, Waehringer Gürtel 18-20, 1090 Vienna, Austria. Electronic address: pascal.baltzer@meduniwien.ac.at.
P A
PA
Baltzer
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000145:classification / Q000473:pathology*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007680:Kidney Neoplasms / Q000145:classification / Q000473:pathology*; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
ADC; DWI; MRI; Papillary; Renal carcinoma; Renal mass