Prevalence and features of the accesory spleen evaluated by multi̇detector computer tomography

ABSTRACT Aim: The aim of this research work is to determine the prevalence of accessory spleen observed on patients examined for abdomen for various reasons, by dynamic Multidetector Computed Tomography (MDCT); and then to determine the radiological imaging properties of accessory spleen and compare the findings with values found in the literature. Materials and Methods: We retrospectively assessed abdominal dynamic multidetector computed tomography (MDCT) findings of 1000 patients admitted to Dicle University department of radiology between january 2011 and september 2013 with various clinical diagnosis. First, the presence of accessory spleen on the patients is investigated. The prevalence, location, total count, vascular supply, density and size of accessory spleens are evaluated. Splenectomised patients were excluded from the study. Archive from our radiology clinic and patient records which comprise 16 detector (Toshiba Activion) and 64 detector (Philips Brillance) CT studies have been used. Findings: We observed total of 281 accessory spleens on 233 (23,3 %) of the examined 1000 patients. Over these 233 patients, 196 (19,6 %) of them was found with one, 29 (2,9 %) with two, 6 (0,6 %) with three, one (0,1 %) with four and one (0,1 %) with five accessory spleens. The measured anteroposterior diameters of accessory spleens were between 3 mm and 37 mm with average of 10,1 mm; their transverse diameters were between 3 mm and 33 mm with average of 9,8 mm; and craniocaudal diameters were between 3 mm and 42 mm with average of 9,6 mm. 234 (83,3 %) of accessory spleens were round and 47 (16,7%) were oval shaped. We examined the location of accessory spleens according to 8 anatomical compartments. 116 (41,4 %) of accessory spleens were anteromedial, 49 (17,5 %) were posteromedial, 38 (13,5 %) were anterior, 32 (11,4 %) were anterolateral, 23 (8,2 %) were posterolateral, 20 (7,1 %) were inferior, 1 (% 0,3) was posterior and 1 (% 0,3) of them was superior compartment located. Another one was accessory spleen accompanied to the wandering spleen, and placed on the lower left quadrant. The density of accessory spleens were between 5 to 95 HU, with 37,7 HU average. The vascular branches supply accessory spleens were detected on 193 (68,7 %) and not detected on 88 (31,3 %) of the patients. Lobulation with cleft is observed on 270 (27 %), only cleft on 225 (22,5 %), only lobulation on 217 (21,7 %), nodule on 3 (% 0,3), nodule with lobulation on 2 (0,2 %), nodule with cleft and lobulation on 1 (0,1 %), splenopancreatic fusion on 1 (0,1 %) and wandering spleen on 1 (0,1 %) congenital anomalies are observed of the screened 1000 patients. No anomaly was detected on 276 (27,6 %) of the patients. Lobulation with cleft is observed on 73 (31,3 %), only cleft on 51 (21,8 %), only lobulation on 53 (22,7 %), nodule with lobulation on 1 (0,4 %), nodule with cleft on 1 (0,4 %), and wandering spleen on 1 (0,4 %) congenital anomalies are observed of the patients with accessory spleen. No anomaly was detected on 54 (23,1 %) of the patients. Conclusions: Accessory spleen is frequently observed and it has a high incidental detection rate on thin-cross-section MDCT. The appearances of accessory spleens are typically with 1 cm average diameter, mostly round shaped and well-marginated. The sizes of accessory spleens tend to increase on patients with splenomegaly. Accessory spleen is most frequently located on anteromedial of the spleen. It has a similar density with spleen. The vascular branches supply accessory spleens are usually detectable on thin-cross-section MDCT. Keywords: Accessory spleen, congenital spleen anomalies, multidetector computed tomography