Guyader D, Gandon Y, Deugnier Y, Jouanolle H, Loreal O, Simon M, Bourel M, Carsin M, Brissot P
INSERM U49, Clinique Médicale B. Pontchaillou Hospital, Rennes, France.
Gastroenterology. 1989 Sep;97(3):737-43. doi: 10.1016/0016-5085(89)90646-x.
The aim of the present study was to evaluate the effectiveness of single-energy computed tomography in determining iron overload in idiopathic hemochromatosis, with special reference to slightly overloaded cases. Liver attenuation was determined in 100 patients (46 cases of idiopathic hemochromatosis, 32 cases of chronic liver disease, and 22 normal controls). The iron load was determined for the first two groups by biochemical determination of liver iron concentration (performed in all but 12 subjects in the chronic liver disease group) and hepatic histologic grading. The main results for liver attenuation (upper normal limit, 72 Hounsfield units) showed that despite a high specificity (0.96), this parameter was of low sensitivity (0.63). Although mean liver attenuation in idiopathic hemochromatosis (77 +/- 14) was significantly higher than in chronic liver diseases (53 +/- 17; p less than 10(-4) and normal controls (66 +/- 3; p less than 10(-3], and despite an overall good correlation between liver attenuation and liver iron concentration (r = 0.72; p less than 10(-3], liver attenuation was unable to detect moderate iron overload. Fourteen of 18 patients with a liver iron concentration of less than 150 mumol/g dry liver wt had liver attenuation values of less than 72. Moreover, 3 of 18 subjects with a liver iron concentration of greater than 150 had a liver attenuation of less than 72. Of these 17 false-negatives, only 7 could be attributed to associated steatosis. On the whole, single-energy computed tomography, when used on a routine basis for diagnosing iron overload, is of limited clinical value in idiopathic hemochromatosis due to its poor sensitivity. Hepatic histologic examination together with biochemical determination remains the most accurate means to assess liver iron.
本研究的目的是评估单能量计算机断层扫描在确定特发性血色素沉着症中铁过载的有效性，尤其针对轻度过载病例。对100例患者（46例特发性血色素沉着症、32例慢性肝病和22例正常对照）测定肝脏衰减值。通过生化测定肝脏铁浓度（慢性肝病组除12例受试者外均进行了此项测定）和肝脏组织学分级来确定前两组的铁负荷。肝脏衰减的主要结果（正常上限为72亨氏单位）显示，尽管该参数具有较高的特异性（0.96），但其敏感性较低（0.63）。尽管特发性血色素沉着症患者的平均肝脏衰减值（77±14）显著高于慢性肝病患者（53±17；p＜10⁻⁴）和正常对照（66±3；p＜10⁻³），并且肝脏衰减与肝脏铁浓度总体上具有良好的相关性（r = 0.72；p＜10⁻³），但肝脏衰减无法检测出中度铁过载。18例肝脏铁浓度低于150μmol/g干肝重的患者中有14例肝脏衰减值低于72。此外，18例肝脏铁浓度高于150的受试者中有3例肝脏衰减值低于72。在这17例假阴性中，只有7例可归因于合并的脂肪变性。总体而言，单能量计算机断层扫描在常规用于诊断铁过载时，由于其敏感性较差，在特发性血色素沉着症中的临床价值有限。肝脏组织学检查结合生化测定仍然是评估肝脏铁的最准确方法。
