[Echography and magnetic resonance of the penis. I. Its anatomy]

The use of such new diagnostic imaging methods as ultrasonography (US) and Magnetic Resonance Imaging (MRI) has given radiology an increasingly important role in the study of penis abnormalities. The normal anatomy of the penis was investigated with US with real-time units, high-frequency linear probes, and with an 0.5-T MR unit. The two methods are definitely better than conventional radiologic techniques because they allow the direct and detailed demonstration of all anatomical structures. Both the normal and the abnormal anatomy are better depicted when the exam is performed after pharmacologically induced erection. The normal US and MR features of the different anatomical structures must be known to diagnose penis conditions. US exhibited better spatial resolution than MRI and demonstrated very small structures which may be missed at MRI because of gap interslices. On the other hand, MRI exhibited better contrast resolution, especially on T2-weighted sequences. Thus, the two imaging methods must be considered as complementary, even though US is suggested as the method of choice because of its cost-effectiveness and widespread availability.