Abdominal CT Scan Based Estimation of Splenic Index and Splenic Volume in North Indian Adults

BACKGROUND Exposure of various tropical infections and infestations like tuberculosis, filariasis, malaria, anemia, kala-azar and poor sanitation are major health concerns in Bihar and it’s neighboring state. Spleen size increases in several other diseases e.g., metabolism or storage disorder, malignancies and hematological disorders. Determining the normal parameters of spleen is essential for assessment of splenomegaly in routine ultrasonography (USG) or in the computed tomography (CT) scan. In this study, we wanted to estimate the CT based measurement of splenic dimensions in various planes, splenic index (linear dimension) and splenic volume and also to estimate the relationship of splenic index and splenic volume with age, gender and other splenic dimensions. METHODS It was a retrospective study and data was collected from January 2019 to December 2019. A total of 154 cases (including both genders) of age range 18 - 60 years were collected from the vitrea system (Vitrea software used for the 3-D assessment of splenic volume) and clinical data was collected from the medical record section. CT scan data of only those patients were included who had the clinical history of pain in abdomen, abdominal trauma or other diseases not affecting the spleen. Various measurements including splenic length and thickness at hilum and maximum thickness in axial view and height (maximum interpolar and true vertical height) in coronal views were recorded. RESULTS 154 cases including both gender and age range of 18 - 60 years were included in our study. There were 60 males and 94 females. The average age of the male and female patients was 45.93 +/- 15.19 years and 45.87 +/- 15.12 years respectively. The mean splenic dimensions were 9.03 +/- 1.49 cm in length (axial view), 3.69 +/- 0.05 cm thickness at hilum (axial view) and 9.05 +/- 2.23 cm maximum craniocaudal length and 7.9 +/- 2.96 cm true vertical length (coronal view). Mean splenic index and mean splenic volume were 340.30 +/- 107.39 cm3 and 227.02 +/- 62.22 cm3 respectively. There was statistically significant correlation between splenic volume and maximum craniocaudal length (r2 = 0.4848, P = 0.001), maximum axial length (r2 = 0.4765, P < 0.001) and true vertical length (r2 = 0.3142, P = 0.001) with 95 % confidence interval. For all splenic measurements, there was stronger correlation with maximum craniocaudal length followed by maximum axial length. However, there was no statistically significant correlation either of splenic volume with age in either gender (r2 = 0.019, P = 0.043) or splenic index with age in either gender present (r2 = 0.016, P = 0.059). CONCLUSIONS Maximum splenic length both in coronal (craniocaudal) and axial sections are positively and strongly correlated with splenic volume and splenic index but age of the individuals doesn’t show any correlation either with the splenic volume or with splenic index. Hence, a regional reference of splenic parameters was established with a slightly different range of values reported previously. KEY WORDS Splenic Volume, Splenic Index, Computed Tomography