Torricelli P, Pecchi A, Luppi G, Romagnoli R
Department of Radiology, University of Modena and Reggio Emilia, Policlinico via del Pozzo 71, 41100 Modena, Italy.
Abdom Imaging. 2003 Jan-Feb;28(1):19-27. doi: 10.1007/s00261-001-0127-3.
At early stages, the diagnosis of local recurrence of rectal cancer is often difficult and magnetic resonance imaging (MRI) is currently considered the most accurate method for diagnosing recurrence. We evaluated the role of unhenhanced and gadolinium-enhanced MRI for the diagnosis of local recurrence of rectal cancer.
Thirty-six patients, suspected of having a pelvic recurrence of rectal cancer, were evaluated by a high field strength MRI unit. Unenhanced spin-echo T1- and T2-weighted sequences and gadolinium-enhanced dynamic fast multiplanar spoiled gradient recalled sequences were performed in all patients. The dynamic images were re-elaborated with semiquantitative postprocessing by plotting intensity-time curves and calculating the percentage of signal increase at the end of the first postcontrast dynamic sequence. The pelvic lesions were classified as recurrent or not recurrent by applying the following diagnostic criteria: (a) morphology and signal intensity of the lesion in unenhanced sequences and (b) percentage of enhancement in dynamic enhanced sequences. Diagnosis was confirmed by computed tomography-guided needle biopsy (12 patients), surgery (four patients), clinical and imaging follow-up (20 patients).
The diagnosis was local recurrence in 15 patients and noncancerous lesions in 21 patients. Unenhanced MRI had 80% sensitivity and 86% specificity. Analysis of the percentage of enhancement showed 87% sensitivity and 100% specificity.
In agreement with the literature, our results showed a high sensitivity and specificity for dynamic MRI. This technique thus can be considered an important adjunct to unenhanced MRI, especially in selected cases in which unenhanced MRI cannot rule out local recurrences. However, these results must be validated by further investigations.
在早期阶段，直肠癌局部复发的诊断往往很困难，目前磁共振成像（MRI）被认为是诊断复发最准确的方法。我们评估了非增强和钆增强MRI在直肠癌局部复发诊断中的作用。
36例疑似直肠癌盆腔复发的患者接受了高场强MRI检查。所有患者均进行了非增强自旋回波T1加权和T2加权序列以及钆增强动态快速多平面扰相梯度回波序列检查。通过绘制强度-时间曲线并计算首次对比剂注射后动态序列结束时信号增加的百分比，对动态图像进行半定量后处理重新分析。根据以下诊断标准将盆腔病变分为复发或未复发：（a）非增强序列中病变的形态和信号强度，以及（b）动态增强序列中的增强百分比。通过计算机断层扫描引导下的穿刺活检（12例患者）、手术（4例患者）、临床和影像学随访（20例患者）来确诊。
15例患者诊断为局部复发，21例患者诊断为非癌性病变。非增强MRI的敏感性为80%，特异性为86%。增强百分比分析显示敏感性为87%，特异性为100%。
与文献一致，我们的结果显示动态MRI具有高敏感性和特异性。因此，该技术可被视为非增强MRI的重要辅助手段，尤其是在非增强MRI不能排除局部复发的特定病例中。然而，这些结果必须通过进一步的研究来验证。
