Ultrasmall superparamagnetic iron oxide enhanced MR imaging for lymph node metastases

The presence of a lymph node metastasis is one of the most important factors influencing therapeutic planning and prognosis in patients with malignancy. For example, a single nodal metastasis approximately halves the survival rate in patients with head and neck cancer, regardless of the location or size of the primary tumor. Currently used imaging techniques such as CT or conventional MRI are unreliable in detecting involved nodes accurately. There are few new techniques that have proven to be of value in nodal staging, and one such technique is ultrasmall superparamagnetic iron oxide (USPIO) contrast agents for MRI. Administered intravenously, USPIO are phagocytosed by macrophages within lymph nodes. Homogeneous uptake of iron oxide particles in normal lymph node shortens the T2 and T2*, turning these nodes dark on post contrast images whereas malignant nodes, lacking the normal physiologic uptake, remain hyperintense on T2- and T2*-weighted images. These differences in signal intensity between normal and metastatic nodes are easily detected visually, leading to high sensitivity and specificity regardless of size or morphological features.This article will review the physiologic properties of USPIO, the technical considerations for imaging using USPIO agent, the results of various clinical trials, and other experimental agents, as well asthe future directions.     

Mediastinal lymph node metastases from bronchogenic carcinoma: detection with MR imaging and CT

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in a prospective study of 48 patients for the detection of metastatic mediastinal lymphadenopathy from bronchogenic carcinoma. The images were interpreted by three experienced radiologists using a five-point rating scale, enabling receiver operating characteristic (ROC) analysis. Imaging results were evaluated against "truth" data based on analysis of surgical specimens from mediastinoscopy and thoracotomy. All MR images were cardiac gated to reduce cardiac motion artifacts in the mediastinum. MR and CT both performed well, as indicated by similar areas under the ROC curves of 0.779 +/- 0.039 for MR imaging and 0.781 +/- 0.038 for CT scanning. No strong correlation between nodal size and metastatic involvement could be found for either MR or CT results. As long as nodal size remains the sole criterion in the detection of metastatic mediastinal lymphadenopathy, MR imaging is unlikely to enable better interpretations than CT scanning.     

Iron oxide-enhanced MR lymphography: The evaluation of cervical lymph node metastases in head and neck cancer

Accurate diagnosis of cervical lymph node metastasis is challenging, even with the latest computed tomography or MR equipment and technique. The lack of definitive criteria for distinguishing metastatic from benign nodes is a serious shortcoming of current imaging options. Dextran-coated, ultrasmall superparamagnetic iron oxide is a new MR contrast agent, which accumulates in the reticuloendothelial system of lymph nodes. Small iron oxide particles are taken up by macrophages within normal functioning nodes, reducing their signal on postcontrast MR because of the magnetic susceptibility effects of iron oxide. Metastatic nodes, on the other hand, remain high in signal on postcontrast T2*-weighted gradient echo images. Early clinical experience in cancer patients suggests that iron oxide-enhanced MR lymphography is a valuable imaging technique that may improve diagnostic accuracy for nodal metastases. This article reviews development of superparamagnetic iron oxide compounds, their imaging characteristics, and clinical experience for evaluating head and neck cancer metastases.     

阳性亲淋巴对比剂增强MR淋巴成像对淋巴结病变的诊断价值

目的 探讨大分子阳性亲淋巴对比剂在间质MR淋巴成像中对肿瘤转移、炎性增生淋巴结的鉴别诊断价值.方法 采用18只纯种新西兰大白兔,体质量2.0～2.5 kg.在其中9只兔一侧后肢各趾蹼处注射完全型免疫佐剂,用于建立腘窝淋巴结炎性增生模型(炎性增生组);另9只兔一侧后肢肌肉接种VX~2瘤建立腘窝淋巴结肿瘤转移模型(肿瘤转移组).对侧正常腘窝淋巴结作为对照.各组每只兔接种前后行MR淋巴成像检查.将0.2 ml二氨基乙基乙二醇醚-DTPA酰胺共聚物钆配合物(Gd-poly-DTPA-EOEA)注入各组每只兔双侧后肢足背部各趾蹼处的皮下.在注射对比剂前后分别进行3D T_1WI扫描和MIP图像重组.在增强3D MIP图像上测量每一腘窝淋巴结短轴最大径(MSAD),在每只兔胭窝淋巴结中选取直径最大者测量其延迟扫描各观察时点的信噪比(SNR).采用成组设计t检验比较炎性增生组与肿瘤转移组腘窝淋巴结接种后MSAD的差异和每一观察时点炎性增生组、肿瘤转移组、正常对照侧腘窝淋巴结间的SNR差异.分析各组腘窝淋巴结的MR淋巴成像图像,并与病理检查相对照.结果 肿瘤组2只兔接种未成功,其他模型形成良好.13个炎性增生、11个肿瘤转移腘窝淋巴结的MSAD分别为(1.32±0.14)cm和(1.33±0.12)cm,差异无统计学意义(t=0.186,P＞0.05).延迟扫描5、15、30、60、90、120 min,9个炎性增生腘窝淋巴结与正常对照侧腘窝淋巴结的SNR值分别为17.31±0.37和17.19±0.29、27.42±0.50和27.39±0.48、38.44±0.47和38.19±0.27、37.10±0.09和36.97±0.10、36.32±0.61和36.20±0.80、34.60±0.44和34.71±0.32,两组间各对应时点SNR值的差异均无统计学意义(t值分别为0.78、0.14、1.43、1.00、0.36、-0.62,P值均＞0.05).7个肿瘤转移腘窝淋巴结和正常对照侧腘窝淋巴结的SNR值分别为6.00±0.22和17.21±0.28、7.87±0.16和27.17±0.23、8.14±0.24和38.16±0.19、8.09±0.28和36.94±0.30、7.59±0.20和35.96±0.72、7.50±0.14和34.81±0.27,两组间各对应时点SNR值的差异均有统计学意义(t值分别为-84.00、-182.72、-261.27、-186.48、-100.22、-239.00,P值均＜0.01).炎性增生组淋巴结的SNR值明显高于肿瘤转移组,差异有统计学意义(t值分别为83.97、174.07、158.49、152.71、96.06、154.57,P值均＜0.01).肿瘤转移淋巴结在MR淋巴成像图像上表现为淋巴结完全或部分的信号缺损.结论 通过阳性亲淋巴对比剂增强MR淋巴成像可提供解剖背景下淋巴结解剖和功能方面的信息,是特异性地鉴别良、恶性淋巴结的敏感检查方法.     

Axillary lymph node metastases in breast cancer: preoperative detection with US

The importance of axillary node status in the prognosis of breast cancer led the authors to conduct a prospective study comparing the value of clinical examination with ultrasound (US) performed by a transpectoral approach. All 60 patients examined underwent axillary dissection. Sensitivity was 45.4% for clinical examination versus 72.7% for US. US provides valuable information for breast cancers treated solely by irradiation, after insufficient dissection, and for large tumors not amenable to primary surgery. When the nodal region is treated by surgery and/or radiotherapy, local monitoring with US appears unnecessary owing to the low incidence of nodal recurrence.     

Axillary lymph node metastases in breast cancer: preoperative detection with dynamic contrast-enhanced MRI

Metastatic involvement of axillary lymph nodes is one of the most important prognostic variables in breast cancer. The aim of our work was to study the value of dynamic contrast-enhanced MR imaging in revealing axillary lymph node metastases from breast cancer. A total of 65 patients with invasive breast cancer treated with axillary lymph node dissection were preoperatively evaluated by MRI. T1-weighted dynamic contrast-enhanced 3D images were acquired using a coil covering the breast and the axilla. The dynamic contrast enhancement, size, and morphology of the axillary lymph nodes were registered. Histopathological examination revealed axillary lymph node metastases in 24 patients. When using a signal intensity increase in the lymph nodes of > 100 % during the first postcontrast image as a threshold for malignancy, 57 of 65 patients were correctly classified (sensitivity 83 %, specificity 90 %, accuracy 88 %). These results were not improved when lymph node size and morphology were used as additional criteria. Axillary lymph nodes can be evaluated as a part of an MR-mammography study without substantial increase in examination time, and provide the surgeon with knowledge about the localization of possible metastatic lymph nodes. Received: 25 February 1999; Revised: 3 August 1999; Accepted: 27 January 1999     

Axillary lymph node metastases in patients with breast carcinomas: assessment with nonenhanced versus uspio-enhanced MR imaging

PURPOSE: To prospectively assess the accuracy of nonenhanced versus ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance (MR) imaging for depiction of axillary lymph node metastases in patients with breast carcinoma, with histopathologic findings as reference standard. MATERIALS AND METHODS: The study was approved by the university ethics committee; written informed consent was obtained. Twenty-two women (mean age, 60 years; range, 40-79 years) with breast carcinomas underwent nonenhanced and USPIO-enhanced (2.6 mg of iron per kilogram of body weight intravenously administered) transverse T1-weighted and transverse and sagittal T2-weighted and T2*-weighted MR imaging in adducted and elevated arm positions. Two experienced radiologists, blinded to the histopathologic findings, analyzed images of axillary lymph nodes with regard to size, morphologic features, and USPIO uptake. A third independent radiologist served as a tiebreaker if consensus between two readers could not be reached. Visual and quantitative analyses of MR images were performed. Sensitivity, specificity, and accuracy values were calculated. To assess the effect of USPIO after administration, signal-to-noise ratio (SNR) changes were statistically analyzed with repeated-measurements analysis of variance (mixed model) for MR sequences. RESULTS: At nonenhanced MR imaging, of 133 lymph nodes, six were rated as true-positive, 99 as true-negative, 23 as false-positive, and five as false-negative. At USPIO-enhanced MR imaging, 11 lymph nodes were rated as true-positive, 120 as true-negative, two as false-positive, and none as false-negative. In two metastatic lymph nodes in two patients with more than one metastatic lymph node, a consensus was not reached. USPIO-enhanced MR imaging revealed a node-by-node sensitivity, specificity, and accuracy of 100%, 98%, and 98%, respectively. At USPIO-enhanced MR imaging, no metastatic lymph nodes were missed on a patient-by-patient basis. Significant interactions indicating differences in the decrease of SNR values for metastatic and nonmetastatic lymph nodes were found for all sequences (P < .001 to P = .022). CONCLUSION: USPIO-enhanced MR imaging appears valuable for assessment of axillary lymph node metastases in patients with breast carcinomas and is superior to nonenhanced MR imaging.     

Breast sentinel lymph node mapping at CT lymphography with iopamidol: preliminary experience

PURPOSE: To evaluate sentinel lymph node (SLN) mapping with interstitial computed tomographic (CT) lymphography with small volumes of iopamidol for direction of SLN biopsy in breast cancer. MATERIALS AND METHODS: Thin-section transverse and three-dimensional CT images that included the breast and axilla were acquired at multi-detector row helical CT in 17 patients with operable breast cancer before subcutaneous injection of 2 mL of undiluted iopamidol into peritumoral and periareolar areas and 1-5 minutes after massage of injection sites. Location and size of SLNs were assessed at CT lymphography and were compared with SLNs at standard axillary lymph node dissection with blue dye staining. RESULTS: CT lymphography allowed localization of SLNs in all patients by means of visualization of a direct connection between an SLN and its afferent lymphatic vessels draining from the injection sites. Afferent vessels were joined and drained into a single axillary SLN, except in four patients with two or three SLNs, including a parasternal one. SLNs did not enhance because of rerouting of lymph flow in four patients. At surgery, SLNs that were stained or not stained with blue dye were easily found with CT lymphographic guidance. Tumoral infiltration was not evident in any resected nodes, except for infiltration in one patient with micrometastasis in SLN alone and infiltration in four patients with massive metastasis in both SLN and distant nodes. CONCLUSION: Because preoperative CT lymphography-guided SLN mapping provides SLN position with detailed lymphatic anatomy, it may be useful for the direction of breast SLN biopsy.     

肾血管平滑肌脂肪瘤伴腹膜后淋巴结转移1例

患者 女,59岁。左上腹不适2月,入院 B 超检查示左肾占位。CT 平扫示左肾类圆形稍高密度占位,外生性生长,直径约2.8 cm,边界清晰,内部密度均匀,左肾前筋膜增厚(图1);增强后病灶动脉期及实质期均明显均匀强化(图2);腹膜后可见数枚淋巴结,最大直径约2.0 cm,与肾脏病灶同期一致均匀强化(图3);三维血管成像示病灶未见有明显肾动脉分支供血血管(图4)。     

Unusual sites of lymph node metastases and pitfalls in their detection

This pictorial review discusses and illustrates unusual sites of lymph node metastases and their mimics.     

MR lymphography with superparamagnetic iron oxide for sentinel lymph node mapping of N0 early oral cancer: A pilot study

Objectives:The purpose of this pilot study was to evaluate the usefulness of magnetic resonance lymphography (MRL) with superparamagnetic iron oxide (SPIO) in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer, and to conduct a comparative study of this MRL with CT lymphography (CTL).Methods:CTL and MRL were performed for SLN mapping before surgery for 20 patients with clinically N0 early oral cancer. The detection rate, number, and location of SLNs in CTL and MRL were evaluated. Furthermore, optimal scanning/imaging timing in MRL was examined.Results:SLNs were detected by CTL in 18 (90%) patients, and the total and mean number of SLN were 35 and 1.8, respectively. All SLNs could be detected 2 min and 3.5–5 min after contrast medium injection. In all patients, SLNs were detected by MRL at 10 min after SPIO injection, and the total and mean number of SLN was 53 and 2.7, respectively. MRL at 30 min after the injection showed additional 18 secondary lymph nodes.Conclusion:MRL with SPIO is safe and useful imaging for the detection of SLNs in clinically N0 early oral cancer, and the optimal imaging timing is 10 min after SPIO injection.     

Invasion of the carotid artery and jugular vein by lymph node metastases: detection with sonography

Knowledge of invasion of the walls of the cervical vessels by tumor is of great clinical importance before surgery. We performed sonography on 83 patients with palpable cervical lymph node metastases in the region of the carotid bifurcation to determine the relationship of the metastases to the carotid artery and jugular vein. In all patients, the sonographic results were proved by surgery. The wall of the carotid artery was hypo-echogenic in 11 of 12 patients with surgically proved tumor invasion of the artery. Four results were false-positive. Palpation or swallowing during real-time scanning showed mobility of the tumor relative to the wall of the artery in 47 patients (57%). In these patients, tumor invasion could be excluded. Bilateral compression or invasion of the internal jugular vein was identified correctly with sonography in all five patients in whom this was confirmed surgically. These results suggest that real-time sonography is a valuable method for determining the relationship between cervical lymph node metastases and the carotid artery and jugular vein.     

Breast sentinel lymph node navigation with three-dimensional interstitial multidetector-row computed tomographic lymphography

OBJECTIVE: Three-dimensional multidetector-row computed tomographic lymphography (3D MDCT-LG) with interstitial injection of a widely available nonionic monometric contrast medium iopamidol was used for navigation of breast sentinel lymph node (SLN) biopsy. METHODS: 3D MDCT-LG was obtained after massage of the interstitially injection sites of a total of 4-5 mL undiluted iopamidol at periareolar and peritumoral areas in 68 consecutive patients with early-stage breast cancer, using a 4 detector-row CT scanner. Drainage lymphatic patterns and SLN anatomy were assessed on 3D MDCT-LG images. 3D MDCT-LG-navigated SLN biopsy with combined use of blue dye was followed by backup axillary lymph node dissection to evaluate accuracy of SLN biopsy. RESULTS: The 3D MDCT-LG images clearly localized primary SLNs by visualizing the direct connection between these nodes and their afferent lymphatic vessels on detailed anatomy of the surrounding structures in all patients. Drainage lymphatic pathways on these images were classified into 4 patterns: single route/single SLN (39 cases, 57%), multiple routes/multiple SLNs (10 cases, 15%), single route/multiple SLNs (9 cases, 13%), and multiple routes/single SLN (10 cases, 15%). Under 3D MDCT-LG navigation, SLNs was found at the accurate location in all patients. With backup axillary lymph node dissection, metastasis was found in 14 (20%) patients, and 8 of these patients had metastasis only in the preoperatively identified SLNs. In other 5 positive patients, metastasis was found both in the SLN and non-SLNs. However, micrometastasis eventually was found only in non-SLN in an elderly patient. Overall, the sensitivity, false-negative rate, and accuracy of 3D CT-L-navigated SLN biopsy were 92% (13/14 patients), 7% (1/14 patients), and 98% (67/68 patients), respectively. CONCLUSIONS: Topographic 3D interstitial MDCT-LG can be a widely available and reliable navigator for breast SLN biopsy.     

Lymphotropic nanoparticle enhanced MR imaging (LNMRI) technique for lymph node imaging

Accurate nodal staging is important in the management of any primary malignancy. The presence of nodal metastases has both therapeutic and prognostic implications. Lymphotropic nanoparticles are a new class of MRI contrast agents, which are promising in detecting minimal metastatic nodal disease particularly in normal sized lymph nodes. This paper discusses the technique and interpretation of lymphotropic nanoparticle enhanced MRI (LNMRI) and reviews the various trials evaluating nodal staging with ferumoxtran-10 enhanced MRI.     

Sonography in cervical lymph node metastases

The value of high resolution real time sonography for the detection of cervical lymph-node metastases in head and neck cancers was assessed in 118 histological proven cases. The accuracy of sonography (89%) proved to be superior to palpation (80%). In 9 patients a thrombosis of the internal jugular vein was detected. The ability of sonography to detect tumorous infiltration of the arterial vessel wall is discussed in 12 patients. Regarding possible artefacts, sonography is the only imaging modality which can solve this problem. Sonography should be performed preoperatively in all patients with malignant head and neck tumors for cervical lymph-node staging.