Multimodality Imaging of Helminthic Infections

Abstract

Parasitic worms (ie, helminths) encompass a broad spectrum of organisms that lead to a myriad of acute, chronic, and multisystemic disease manifestations rooted in the life cycles of helminths, their migratory paths within humans, and the immunologic reactions they provoke. Although geographic distribution is traditionally given substantial consideration in the process of diagnosing these diseases, increased world travel and migration has resulted in cases all over the world. Because physicians in areas where these organisms are nonendemic are less likely to be familiar with them, the diseases are unexpected, resulting in difficulty and delay in diagnosis and appropriate treatment of patients. The authors aim to familiarize radiologists with helminthiases and their imaging findings, including diseases caused b y cestodes (tapeworms) such as Echinococcus granulosus and Taenia solium, trematodes (flatworms) such as Clonorchis sinensis and Schistosoma species, and nematodes (roundworms) such as Ascaris lumbricoides and various types of filaria. By interlinking parasite transmission and disease development mechanisms with the observable patterns at imaging, the authors help to elucidate how and why these manifestations appear as they do. Radiologists will enhance their ability to identify typical and atypical sequelae of helminthiases with multiple imaging modalities, including US, CT, and MRI and other imaging techniques, using an organism-based approach.