Normative assessment of renal dimensions from computed tomography

BACKGROUND: The values measured by ultrasound for normal renal dimensions in adults are well established, but not much is known about the normal renal size of Nepalese subjects from computed tomography (CT). This study aimed to establish normal CT values for kidney dimensions from patients undergoing contrast-enhanced CT (CECT) abdomen examination. MATERIALS AND METHODS: This was a cross-sectional study carried out in patients undergoing CECT scan with different clinical history excluding abnormalities with the urinary system. The study consisted of the measurement of 212 bilateral kidneys in 106 adults. The kidney length (KL) from pole to pole, kidney width (KW), and cortical widths (CW) at the upper, middle, and lower pole were measured. For measuring length, axes were adjusted for each kidney in double oblique sagittal planes, for the width of kidney and cortex in double oblique coronal planes using a 3D-software available in the scanner (Neosoft). Analyses for normal distribution, t-tests, and correlation were performed using SPSS version 20 (IBM, USA). RESULTS: KL was 95.52 ± 8.91 mm for the right kidney (RK), and 98.22 ± 8.85 mm for the left kidney (LK). CW at the upper, middle, and lower poles on RK was 5.33 ± 0.97 mm, 5.29 ± 0.97, and 5.03 ± 0.88 mm, whereas on the LK was 5.30 ± 0.94 mm, 5.19 ± 0.97, 5.03 ± 0.96 mm, respectively. The KW was 49.15 ± 5.76 mm and 49.11 ± 5.52 mm on RK and LK, respectively. The most significant independent factors for KL and KW were age, body surface area (BSA), gender, height, and weight and were found to be statistically significant (P< 0.05 each). CONCLUSIONS: We established the normal references of various renal measurements which provide the radiologists and the referring clinicians an insight about the normal range of different renal parameters. Since there are several influencing factors on kidney size, the assessment should be made individually. The major influencing factors found are BSA, height, gender, age, and weight.