Anatomical features of cephalothoracopagus variations: CT and MRI.

Conjoined twins have fascinated human mankind for a long time. Until recently, their description was limited to the dissection of non-viable cases, the description of external features and of bones by x-ray imaging. The introduction of ultrasonographic techniques gave the first in uterus images of conjoined twins, though the spatial resolution did not allow detailed descriptions. Subsequently, CT and MRI techniques allowed more precise definition of organs without any dissection, thus the need of formal interpretation of similar new images. As a matter of fact, few monstrosities have been studied by CT and MRI techniques. To this day very few cases still lack any CT/MRI documentation. Here we present a very rare type of cephalothoracopagus twins (joined at the head and the thorax). They have been accurately examined by CT and MRI imaging to study visceral structures. Pathophysiology and genetic aspects are also reviewed. These data offer precious details for accurate comprehension of imaging studies, and for theoretical studies concerning the information of several anatomical structures.