Koh Dow-Mu, Brown Gina, Temple Louis, Raja Asraf, Toomey Paul, Bett Nicholas, Norman Andrew R, Husband Janet E
Department of Academic Radiology and Medical Statistics, Royal Marsden Hospital, Downs Rd, Sutton SM2 5PT, England.
Radiology. 2004 Apr;231(1):91-9. doi: 10.1148/radiol.2311030142. Epub 2004 Feb 19.
To compare histopathologic findings with appearances of mesorectal lymph nodes at magnetic resonance (MR) imaging with ultrasmall particles of iron oxide (USPIO) in rectal cancer.
Mesorectal lymph nodes in 12 patients with adenocarcinoma of the rectum were evaluated with USPIO and high-spatial-resolution MR imaging. Appearance and signal intensity of lymph nodes at T2- and T2*-weighted imaging were recorded before and after USPIO administration. Two radiologists visually assessed pattern of enhancement; interobserver agreement was tested with the kappa statistic. After total mesorectal excision, MR imaging of surgical specimens was performed, and it enabled node-by-node correlation with histopathologic findings.
Appearances of 74 nodes at in vivo MR imaging were compared with histopathologic findings. Sixty-eight nodes were nonmalignant (34 were normal, 34 showed reactive changes); six nodes were malignant. Four patterns of USPIO uptake were demonstrated at T2*-weighted imaging: uniform low signal intensity, central low signal intensity, eccentric high signal intensity, and uniform high signal intensity. Two radiologists showed good interobserver agreement (kappa = 0.88, P <.01) in classification of nodes into these four categories. Sixty-five (96%) of 68 nonmalignant nodes showed uniform or central low-signal-intensity patterns; 16 (47%) of 34 reactive nodes showed central low-signal-intensity patterns. Compared with uniform low-signal-intensity pattern, central low-signal-intensity pattern was more commonly observed in reactive nodes (P <.01, chi(2) test; positive predictive value, 67%; 95% CI: 47%, 87%). Eccentric and uniform high-signal-intensity patterns were observed in lymph nodes that contained metastases larger than 1 mm in diameter.
Mesorectal lymph nodes can be characterized by using USPIO and T2*-weighted MR imaging. Uniform and central low-signal-intensity patterns are features of nonmalignant nodes. Reactive nodes frequently show central low signal intensity at T2*-weighted imaging.
比较直肠癌患者经超小超顺磁性氧化铁（USPIO）磁共振（MR）成像时直肠系膜淋巴结的组织病理学表现与影像表现。
对12例直肠腺癌患者的直肠系膜淋巴结采用USPIO和高空间分辨率MR成像进行评估。在注射USPIO前后记录T2加权成像和T2*加权成像时淋巴结的外观及信号强度。两名放射科医生通过视觉评估强化模式；采用kappa统计量检验观察者间的一致性。在进行全直肠系膜切除术后，对手术标本进行MR成像，从而实现与组织病理学表现的逐个淋巴结相关性分析。
将体内MR成像时74个淋巴结的表现与组织病理学结果进行比较。68个淋巴结为非恶性（34个正常，34个显示反应性改变）；6个淋巴结为恶性。在T2*加权成像上显示出四种USPIO摄取模式：均匀低信号强度、中央低信号强度、偏心高信号强度和均匀高信号强度。两名放射科医生在将淋巴结分为这四类时观察者间一致性良好（kappa = 0.88，P <.01）。68个非恶性淋巴结中的65个（96%）显示均匀或中央低信号强度模式；34个反应性淋巴结中的16个（47%）显示中央低信号强度模式。与均匀低信号强度模式相比，中央低信号强度模式在反应性淋巴结中更常见（P <.01，卡方检验；阳性预测值为67%；95%可信区间：47%，87%）。在直径大于1 mm的转移淋巴结中观察到偏心和均匀高信号强度模式。
可通过USPIO和T2加权MR成像对直肠系膜淋巴结进行特征性描述。均匀和中央低信号强度模式是非恶性淋巴结的特征。反应性淋巴结在T2加权成像上常显示中央低信号强度。
