Colagrande S, Bartolozzi A, Tonarelli A
Dipartimento di Fisiopatologia Clinica, Università degli Studi di Firenze.
Radiol Med. 1994 Apr;87(4):469-81.
128 Magnetic resonance (MR) investigations of single or multifocal nodular liver lesions were retrospectively reviewed. All lesions had been identified, but not characterized, with ultrasonography (US). All the studies were performed with a 0.5-T superconductive magnet (Philips Gyroscan); spin-echo (SE) T1/proton density/T2-weighted and inversion recovery (IR) pulse sequences were used routinely. Characterization was attempted considering the following variables: a) lesion outline; b) the presence of some kind of capsular or pseudocapsular ring; c-d) homogeneity of signal intensity and its difference from surrounding liver parenchyma; e) possible central scar and its signal features; f) associated lesions (multifocal nodules, ascites, locoregional adenopathies, venous thrombosis). Diagnostic confirmation was obtained by means of biopsy (63 patients), of other imaging techniques (35 patients), or of clinical follow-up over 12 months at least (30 patients). Our results confirm high MR accuracy in the diagnosis of hemangioma (48/50 cases, 96% confidence) and even higher accuracy in focal fatty liver infiltration (9/9 cases, 100% confidence), thanks to some typical MR signal patterns on appropriate acquisition techniques--i.e., SE multiecho pulse sequences and IR sequences, respectively, with liver and fat signal nulling. Primary non-malignant focal liver lesions were identified mainly on a morphological basis (smooth roundish outline with/without capsular or pseudocapsular ring; central starlet scar; "basket" or "spoked wheel" patterns): these features allowed the correct identification of 5/7 focal nodular hyperplasia cases. On the other hand, in the absence of these typical morphological features and of specific MR signal changes, adenomas were misdiagnosed in all cases but one. The study of focal lesions in cirrhotic liver disease exhibited 66.6% confidence in the diagnosis of regenerating nodules, on the basis of their iso/hypointensity relative to liver on T2-weighted pulse sequences. Such a behavior seems to be due to intracellular iron loading, to small cell size and to thin vascular network, which are typical of cirrhotic regenerating areas. The diagnosis of hepatocellular carcinoma relies on both morphostructural features and possible associated lesions: in our series, 22/25 cases (88% confidence) were correctly identified. Indeed, this result was somehow influenced by the case history of the patients and by specific serologic indexes. Finally, MRI exhibited high sensitivity in the detection of focal liver involvement in neoplastic patients. However, the intrinsic range of variability and the lack of specificity of MR signal intensity, because of different histopathologic cell types, do not usually allow an unquestionable diagnosis to be made, especially for single lesions.
对128例单发或多发结节性肝病变的磁共振（MR）检查进行了回顾性分析。所有病变均经超声（US）检出，但未明确其特征。所有检查均使用0.5T超导磁体（飞利浦Gyroscan）；常规采用自旋回波（SE）T1/质子密度/T2加权及反转恢复（IR）脉冲序列。根据以下变量进行特征分析：a）病变轮廓；b）是否存在某种包膜或假包膜环；c - d）信号强度的均匀性及其与周围肝实质的差异；e）可能存在的中央瘢痕及其信号特征；f）相关病变（多发结节、腹水、局部淋巴结肿大、静脉血栓形成）。通过活检（63例患者）、其他影像学检查（35例患者）或至少12个月的临床随访（30例患者）获得诊断证实。我们的结果证实，MR对血管瘤的诊断具有较高准确性（48/50例，96%置信度），对局灶性脂肪肝浸润的诊断准确性更高（9/9例，100%置信度），这得益于在适当的采集技术上出现的一些典型MR信号模式，即分别在SE多回波脉冲序列和IR序列上，肝和脂肪信号被抑制。原发性非恶性局灶性肝病变主要根据形态学特征进行识别（轮廓光滑呈圆形，有/无包膜或假包膜环；中央星芒状瘢痕；“篮状”或“辐轮状”模式）：这些特征使7例局灶性结节性增生病例中的5例得以正确识别。另一方面，在缺乏这些典型形态学特征和特定MR信号改变的情况下，除1例之外，所有腺瘤均被误诊。对肝硬化肝脏疾病中的局灶性病变进行研究发现，基于T2加权脉冲序列上相对于肝脏的等/低信号强度，对再生结节的诊断置信度为66.6%。这种表现似乎归因于细胞内铁负荷增加、细胞体积小以及血管网络稀疏，这些都是肝硬化再生区域的典型特征。肝细胞癌诊断依赖于形态结构特征及可能存在的相关病变：在我们的系列研究中，25例中有22例（88%置信度）被正确识别。实际上，这一结果在一定程度上受到患者病史和特定血清学指标的影响。最后，MRI在检测肿瘤患者肝脏局灶性受累方面具有较高敏感性。然而，由于不同组织病理学细胞类型导致的MR信号强度固有变异性范围以及缺乏特异性，通常无法做出明确诊断，尤其是对于单个病变。
