The role of shear wave ultrasound elastrography in the differential diagnosis of splenomegaly

ABSTRACT The Role Of Shear Wave Ultrasound Elastrography In The Differential Diagnosis Of Splenomegaly The aim of this study is to investigate the power of discriminating splenomegaly caused by portal hypertension, infiltration and lymphoid hyperplasia based on the measurement of tissue hardness of shear wave elastography (SWE), one of the ultrasound examination methods. Between November 2016 and September 2017, patients who admitted to the Department of Radiology of the Faculty of Medicine of Fırat University for abdominal ultrasonography (US) evaluation and diagnosed as splenomegaly were evaluated by SWE. Of these, 49 patients (32 males, 17 females, mean age 43.5 ± 22.1) with a known cause of splenomegaly which determined by diagnostic methods in our hospital registry were included in the study. Thirty-four subjects (19 males, 14 females, mean age 40 ± 15.2) with normal size spleen and no known disease that could affect the spleen were included in the control group. The causes of spleen enlargement were divided into three groups: portal hypertension, lymphoid hyperplasia and infiltration. The SWE evaluation was performed with a 1-5 MHz convex transducer from coronal oblique views of the spleen and the spleen stiffness was measured in units of kPa (kilopascal). Spleen stiffness was 14.11±4.14, 16.63±8.36 and 10.58±4.77 kPa in spleen enlargement due to lymphoid hyperplasia, portal hypertension, and infiltration, respectively. The mean spleen stiffness in the control group was 13.56 ± 2.56 kPa. The stiffest spleen was observed in spleen growth caused by portal hypertension; the spleen stiffness of the patients in this group was significantly higher than both the control group (p = 0.04) and infiltration-induced spleen enlargement (p = 0.01). The difference was not significant in patients with spleen growth due to lymphoid hyperplasia, although the spleen was stiffer than control group (p = 0.63). Although spleen stiffness was apparently higher in spleen growth due to lymphoid hyperplasia than in spleen growth due to infiltration, the difference was not significant (p = 0.08).In patients with spleen growth due to infiltration, spleen was found to be softer than control group (p = 0.005) and portal hypertension at a significant level (p = 0.01). In conclusion, the patients with most stiff spleen were portal hypertension patients and the stiffness of the spleen increased moderately in patients with lymphoid hyperplasia. In infiltrating diseases, the spleen is softer than normal spleen. The spleen stiffness measured by SWE can be helpful in the estimation of cause in patients with first time diagnosis of splenomegaly whose cause is not yet known, noninvasively. Keywords: spleen stiffness, elastography, infiltration, lymphoid hyperplasia, portal hypertension, shear wave elastography (SWE), splenomegaly, ultrasound