Pedram Rezai MD, Presenter: Grant, Siemens AG

Sandra M. Tochetto MD, Abstract Co-Author: Grant, Siemens AG

Vahid Yaghmai MD, Abstract Co-Author: Nothing to Disclose

Accurate radiologic characterization of perinephric hematoma plays a central role in the clinical evaluation and therapeutic decision making. The purpose of this study was to evaluate imaging unidimensional biomarkers of perinephric hematoma and assess their relationship with hematoma volume.

This retrospective, HIPPA compliant study was approved by IRB. 18 patients (13 males, 5 females; median age, 51.5 years) with perinephric hematoma who underwent contrast enhanced abdominal MDCT were evaluated. Ipsilateral kidney and combined ipsilateral kidney/hematoma were segmented separately and hematoma volume was calculated by subtracting the two volumes. Due to complex configuration, reliable determination of the longest diameters of the hematoma per se was not possible. Instead, the following unidimensional diameters of the combined ipsilateral kidney/hematoma were measured: longest trans-axial diameter (Width; W), longest perpendicular diameter to width on the same slice (Thickness; T) and cranio-caudal dimension (Length; L). Pearson correlation, regression analysis, Bland-Altman plot and Lin’s concordance correlation were used for statistical analysis. p<0.05 denotes statistical significant.

Hematoma volume ranged from 87.85 mL to 2431.30 mL. Mean hematoma volume was 587.07 mL (95%CI, 263.40-910.71). Pearson correlation coefficient between hematoma volume and width (cm), thickness (cm), length (cm) and product of W, L and T (WxTxL) was 0.87, 0.82, 0.95 and 0.99, respectively (p<0.05 in all instances). Regression analysis was used to define the relationship between hematoma volume and (WxTxL): Estimated hematoma volume (EHV) (mL) =0.48 (WxTxL) – 236 (R2=0.98, p<0.05). EHV ranged from 38.7 mL to 2271.37 mL. Mean EHV was 588.53 mL (95%CI, 268.23-908.82). Based on the Bland-Altman plot, mean bias between hematoma volume and EHV was 9.61% (95%CI, -8.09% to 27.31%). Lin’s concordance correlation between hematoma volume and EHV was 0.99 which denotes excellent agreement.

Perinephric hematoma volume may be accurately estimated from unidimensional diameters of the combined ipsilateral kidney/hematoma.

By using this simple, applicable method, hematoma volume may be estimated from unidimensional diameters with high accuracy. 

Rezai, P, Tochetto, S, Yaghmai, V, Accurate Estimation of Perinephric Hematoma Volume from Unidimensional Diameters.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8012268.html