We consistently observed small "reflective channels" (RCs) in the splenic parenchyma in patients with portal hypertension (PHT). The purpose of this study was to investigate the frequency of this sign in PHT and in splenic disorders unrelated to PHT compared to normal controls. The significance of this sign in the diagnosis of PHT and in differentiating PHT splenomegalies from others was also assessed. A total of 337 patients underwent sonographic examination of the spleen: 147 normal, 75 non-PHT splenic pathologies, and 115 with PHT. The RCs were scored from grade 0 to 3 by counting the number in an area of 12 mm2 in the splenic parenchyma. Of 222 normal and non-PHT spleens, 174 (78%) showed grade 0, 44 (20%) grade 1, four grade 2 (1%), and none showed grade 3 RCs. Of 115 PHT cases, 17 showed grade 0, 25 grade 1, 44 grade 2, and 29 showed grade 3 RCs. The sensitivity of this sign was 0.85 with a specificity of 0.77 and an accuracy of 0.80 in detecting PHT (p < 0.001). The interobserver and intraobserver variation for grading was insignificant (p > 0.1). The RCs could be explained by periarterial fibrosis and dilatation of venous sinuses with increased collagen in their walls, which is known to occur in PHT. The vascular nature on ultrasound (US) was confirmed by the presence of flow on color Doppler. This sign is readily differentiated from the calcifications of tuberculosis, histoplasmosis, sickle cell infarcts, and phleboliths; it serves as a useful aid in diagnosing and differentiating PHT splenomegaly from non-PHT splenomegaly.