Perinephric hematoma: semi-automated quantification of volume on MDCT: a feasibility study.

Background: To evaluate feasibility and reproducibility of quantification of perinephric hematoma volume on multidetector-row CT (MDCT).
Methods: Perinephric hematomas in 63 patients (42 males, 21 females, median age: 49 years) imaged with contrast-enhanced MDCT of the abdomen were evaluated. A semi-automated segmentation software was applied to quantify hematoma volume. Reproducibility for quantification of hematoma volume was evaluated by repeated measurements in 20 patients. Statistical analyses were performed by using Student's t test. Interobserver and intraobserver variability was evaluated by Bland-Altman plots. P < 0.05 denoted statistical significance
Results: Quantification of hematoma volume was feasible in all cases. One step, direct quantification of volume was possible in 21 patients (33.33%) with small hematomas that did not reach upper and lower renal poles (range: 3.12-183.98 mL; mean: 39.92 mL). Quantification of hematoma size was performed indirectly in 42 patients (66.67%) with larger hematomas that extended beyond the renal poles by subtracting the ipsilateral renal volume from the combined kidney and hematoma volumes (range: 27.08-2431.3 mL; mean: 435.31 mL). Mean quantification time was 45 and 71 s for small and large hematomas, respectively (P < 0.05). Mean intraobserver and interobserver variability for determination of hematoma volume was 0.14% (95% CI, -1.57% to 1.85%) and 2.04% (95% CI, -1.77% to 5.85%), respectively. There was no significant difference in renal volume between ipsilateral and contralateral kidneys (P > 0.05).
Conclusion: Quantification of perinephric hematoma was feasible from MDCT data in all patients and was reproducible.