肝局灶性结节增生的CT与MRI诊断

目的探讨肝局灶性结节增生（FNH）的CT和MRI表现，以提高FNH诊断准确性。方法回顾性分析20例经手术病理证实的24个FNH病灶的影像学资料，包括CT检查13例，MRI检查10例，其中3例同时做了CT及MRI检查。结果18例为单发病灶，2例为多发病灶。CT及MRI检出病灶数均为14个。CT平扫低密度9个，等密度5个。MRI平扫T1WI低信号10个，等信号4个；T2WI显示14个均呈高或稍高信号。所有病灶实质动脉期cT及MRI均明显强化。cT显示门脉期9个等密度，4个稍高密度，1个低密度；延迟期11个等密度，2个稍高密度，1个稍低密度。MRI显示门脉期高信号11个，等信号3个；延迟期高信号10个，等信号4个。CT多期扫描8个病灶伴有中央瘢痕，7个周边有扭曲、增粗血供，3个有假包膜。MRI多期扫描9个病灶伴有中央瘢痕，6个周边有扭曲、增粗血供，5个有假包膜。结论CT及MRI多期扫描可充分反映FNH的供血特点及病理特征，在FNH诊断与鉴别诊断中具有重要的价值。

CT and MR diagnosis on focal nodular hyperplasia of the liver

Objective To explore the appearances of the focal nodular hyperplasia （FNH） using CT and MR imaging, and to improve its diagnostic accuracy of the FNH. Methods CT and MR scanning of pre- and post-contrast arterial phase, portal venous phase and delayed phase were performed on 20 patients with pathologically proved FNH. CT and MR imaging of 24 lesions in 20 cases was retrospectively analyzed, including 13 cases done by CT scan, 10 cases done by MR scan, among which 3 cases done by both CT and MR scan. Results 18 solitary lesions and 2 multiple lesions were revealed. On pre-contrast CT scans, 9 of 14 FNH lesions were hypodense, the other five lesions were isodense. On pre-contrast MR scans, 10 of 14 FNH lesions showed hypointense, the other four lesions showed isointense on T~WI, and all 14 lesions showed hyperintense or slight hyperintense on T2WI. On the arterial phase scans, all lesions were markedly enhanced, except for the central scar area on CT and MR imaging. On the portal phase CT scans, 9 FNH lesions were isodense, 4 lesions were hyperdense, and 1 lesion was hypodense. On the delayed phase CT scans, 11 FNH lesions were isodense, 2 lesions were slight hyperdense, and 1 lesion was slight hypodense. On the portal phase MR scans, 11 FNH lesions shoWed hyperintense, the other three lesions showed isointense. On the delayed phase scans, 10 FNH lesions showed hyperintense, the other four lesions showed isointense. On multiphase CT scanning, central scar was found in 8 FNH lesions; tortuous and dilated arteries at the peripheral area in 7 lesions; and pseudocapsule sign in 3 lesions. On multiphase MR scanning, central scar was seen in 9 FNH lesions; tortuous and dilated arteries at the peripheral area in 6 lesions; and pseudocapsule sign in 5 lesions. Conclusion Multiphase CT and MR scanning can fully reveal the blood supplying and histological characteristic of FNH, which will be very useful in diagnosing and differentiating FNH.