Solitary Hepatic Cysts
Hepatic cysts are common lesions and are usually divided into unilocular (95%) or multilocular varieties.
On MR imaging, cysts are homogeneous, well-defined lesions that possess a sharp boundary with the liver. Occasionally, cysts are so closely grouped that they resemble a multicystic mass. Simple cysts are low in signal intensity on T1-weighted images, markedly high in signal intensity on T2-weighted images.
Single-shot breathing-independent T2-weighted sequences (e.g., SS-ETSE) are especially effective at showing small (≤ 5 mm) cysts. Because cysts do not enhance with gadolinium on MR images, delayed post-gadolinium images (up to 5 min) may be useful to ensure that lesions are cysts and not poorly vascularized metastases that show gradual enhancement (Semelka et al. 1993a).