T1 加权前列腺 MRI 图像中出血外溢征象对前列腺癌检测的价值。
Value of the hemorrhage exclusion sign on T1-weighted prostate MR images for the detection of prostate cancer.
机构信息
Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA.
出版信息
Radiology. 2012 Jun;263(3):751-7. doi: 10.1148/radiol.12112100. Epub 2012 Apr 2.
PURPOSE
To retrospectively determine the prevalence and positive predictive value (PPV) of the hemorrhage exclusion sign on T1-weighted magnetic resonance (MR) images in conjunction with findings on T2-weighted images in the detection of prostate cancer, with use of whole-mount step-section pathologic specimens from prostatectomy as the reference standard.
MATERIALS AND METHODS
The institutional review board approved this retrospective study, which was compliant with HIPAA, and the requirement to obtain informed consent was waived. Two hundred ninety-two patients with biopsy-proved prostate cancer underwent endorectal MR imaging followed by prostatectomy. The hemorrhage exclusion sign was defined as the presence of a well-defined area of low signal intensity surrounded by areas of high signal intensity on T1-weighted images. Two readers independently assessed the presence and extent of postbiopsy changes and the hemorrhage exclusion sign. The presence of a corresponding area of homogeneous low signal intensity on T2-weighted images was also recorded. The prevalence and PPV of the hemorrhage exclusion sign were calculated.
RESULTS
Readers 1 and 2 found postbiopsy changes in the peripheral zone in 184 (63%) and 189 (64.7%) of the 292 patients, respectively. In these patients, the hemorrhage exclusion sign was observed in 39 of 184 patients (21.2%) by reader 1 and 36 of 189 patients (19.0%) by reader 2. A corresponding area of homogeneous low signal intensity was seen on T2-weighted images in the same location as the hemorrhage exclusion sign in 23 of 39 patients (59%) by reader 1 and 19 of 36 patients (53%) by reader 2. The PPV of the hemorrhage exclusion sign alone was 56% (22 of 39 patients) for reader 1 and 50% (18 of 36 patients) for reader 2 but increased to 96% (22 of 23 patients) and 95% (18 of 19 patients) when the sign was identified in an area of homogeneous low signal intensity on T2-weighted images.
CONCLUSION
Postbiopsy change is a known pitfall in the interpretation of T2-weighted images. The authors have shown that a potential benefit of postbiopsy change is the presence of excluded hemorrhage, which, in conjunction with a corresponding area of homogeneous low signal intensity at T2-weighted imaging, is highly accurate for cancer identification.
目的
回顾性分析 T1 加权磁共振（MR）图像中出血排除征象（hemorrhage exclusion sign）结合 T2 加权图像上的表现，用于检测前列腺癌的阳性预测值（PPV），以前列腺切除术的全器官切片病理标本作为参考标准。
材料与方法
该回顾性研究获得了机构审查委员会的批准，符合 HIPAA 规定，且无需获得知情同意。292 例经活检证实患有前列腺癌的患者接受了直肠内 MR 成像检查，随后进行了前列腺切除术。出血排除征象定义为 T1 加权图像上存在边界清晰的低信号强度区域，周围环绕高信号强度区域。两位读者独立评估活检后改变和出血排除征象的存在和程度。还记录了 T2 加权图像上相应的均匀低信号强度区域的存在。计算出血排除征象的患病率和 PPV。
结果
读者 1 和 2 分别在 292 例患者中的 184 例（63%）和 189 例（64.7%）中发现外周带活检后改变。在这些患者中，读者 1 在 39 例患者中的 184 例（21.2%）中观察到出血排除征象，读者 2 在 36 例患者中的 189 例（19.0%）中观察到出血排除征象。在 39 例患者中的 23 例（59%）中，在 T2 加权图像上同一位置观察到与出血排除征象相对应的均匀低信号强度区域，在 36 例患者中的 19 例（53%）中观察到。读者 1 出血排除征象的单独 PPV 为 56%（22/39 例），读者 2 的 PPV 为 50%（18/36 例），但当在 T2 加权图像上均匀低信号强度区域识别出该征象时，PPV 增加至 96%（22/23 例）和 95%（18/19 例）。
结论
活检后改变是 T2 加权图像解释中的一个已知陷阱。作者表明，活检后改变的一个潜在益处是存在排除性出血，当与 T2 加权成像上相应的均匀低信号强度区域结合时，对癌症的识别具有高度准确性。
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