肢体淋巴水肿MR淋巴造影与病理对照的实验研究

目的研究肢体水肿演变过程中不同时期的MR淋巴造影影像特征及其病理基础,探讨MR淋巴造影在肢体淋巴水肿方面的诊断价值。方法用改良的Danese手术方法在13只新西兰大白兔后肢一侧形成淋巴水肿模型,另一侧作为对照。在每只大白兔双侧后肢足背部趾蹼处注射0.2ml欧乃影,于淋巴水肿演变过程的不同时期进行三维MR淋巴造影。取肢体标本进行病理检查。结果MR淋巴造影能准确地确定淋巴管阻塞的部位,反映淋巴管形态、功能的状况。肢体淋巴水肿的不同时期,由于其病理基础不同,产生不同的MR淋巴造影表现。结论间质MR淋巴造影可以在解剖背景下敏感而又可靠地显示各期肢体淋巴水肿。     

Isovist间接淋巴造影诊断淋巴水肿（附20例分析）

为探讨Isovist间接淋巴造影效果,笔者对20例淋巴水肿患者进行间接淋巴造影。此法操作简便,节省时间,反应少,可反复应用,可显示非常细小的初级淋巴管。     

MR淋巴造影在肢体淋巴水肿诊断中的价值

目的 评估MR淋巴造影(MRL)对肢体淋巴水肿的诊断价值.方法 运用3.0T MR对582例肢体淋巴水肿患者进行MRL.并对淋巴结形态及显影情况,淋巴管数目和淋巴速度等进行评估.结果 原发性与继发性淋巴水肿淋巴回流障碍MRL均显示或为淋巴结受累、或为淋巴管受累、或为两者均受累.根据MRL显示的淋巴管数目,原发性淋巴水肿可分为淋巴系统不发育、发育不全和淋巴系统增生3类;继发性淋巴水肿可分淋巴管闭塞减少型和淋巴管开放增多型.动态MRL显示原发性淋巴水肿受累肢体淋巴回流速度平均为(1.0±0.62)cm/min,显著慢于继发性受累肢体平均流速(2.22±1.64)cm/min(P<0.01).在原发性与继发性淋巴水肿中,对侧相比患侧淋巴结MRL均表现为显影数目少、显影延迟和显影信号低.结论 动态MRL能够评估肢体淋巴水肿淋巴系统形态及功能改变,为淋巴水肿诊断提供有力影像手段.     

淋巴水肿的影像学诊断现状

淋巴水肿是由于先天性淋巴管发育不全或后天原因，致使淋巴液回流受阻、返流所引起的肢体浅层软组织内体液积聚、继发纤维组织增生、脂肪硬化、筋膜增厚及整个患肢变粗的病理状态。对于其诊断，一般靠病史，临床表现及体格检查即可。然而依靠上述资料不能确诊或需要更详尽地了解淋巴管形态或功能时，则在很在程度上要依赖影像榆查.     

核素淋巴显像诊断四肢淋巴水肿

应用核素淋巴显像诊断２５例四肢水肿。将显像图分为五种类型，即正常回流（４例）、侧支回流（２例）、混合回流（１３例）、皮肤回流（４例）和无回流型（２例）。８例行显微外科手术。结果表明，核素淋巴显像简便无创，安全可靠，能鉴别水肿性质、显示淋巴回流功能与梗阻程度，以及提供淋巴系统形态、分布变化等信息，对确定治疗方案和选择手术病人很有价值。     

淋巴水肿的影像学诊断

淋巴水肿(lymphedema)是淋巴液回流障碍引起的组织间隙淋巴液异常增多。由于积聚的淋巴液富含蛋白质,长期刺激引起结缔组织异常增生,大量纤维组织替代脂肪组织,导致皮肤及皮下组织增厚,皮肤表面角化、粗糙、硬化,形成典型的“象皮肿”。若合并感染使炎性渗出液增加,刺激结缔组织大量增生,将破坏更多的淋巴管,加重淋巴液滞留和渗出,进一步增加感染机会,形成恶性循环,致使淋巴水肿日益加重。1淋巴水肿分类淋巴水肿根据病因分为原发性及继发性两大类。1·1原发性淋巴水肿①单纯性淋巴水肿。单纯性淋巴水肿是淋巴管先天发育异常所致,表现为淋巴…     

超声造影诊断下肢淋巴水肿的研究进展

下肢淋巴水肿是一种慢性、进行性疾病,严重影响患者生活质量;早期诊断和治疗可延缓病情进展,有利于改善患者预后。目前常见的下肢淋巴水肿诊断技术均具有一定的缺点而使应用受限。超声造影具有无创、便捷、实时、重复性好的特点,能够增强淋巴管中淋巴液的显像,对浅表淋巴管显像具有较高敏感度,近年来逐渐应用于下肢淋巴水肿诊断。本文对超声造影在下肢淋巴水肿中的应用情况进行综述。     

肝脏淋巴异常动力学改变的CT研究

肝脏淋巴系统对于肝内过多组织液的引流起重要作用，许多病因均可致肝内淋巴管扩张，本综述了肝肉淋巴管扩张的ＣＴ表现，病理生理基础，各种引起肝内淋巴管扩张的病因及与梗阻性黄疸的鉴别要点，ＣＴ上出现的肝内血管周围低密度影作为评价肝内异常淋巴动力学的指标已被肯定。其对于各种疾病的敏感性，特性和准确性有待于深入的研究。     

肢体淋巴水肿MR间质淋巴成像技术初探

目的 评价MR间质淋巴成像技术的可行性.方法 对原发性淋巴水肿的31例患者40条下肢进行MR淋巴成像.在双足趾间皮内注入钆贝葡胺与利多卡因的混合液1 ml,采用三维容积内插扰相梯度回波序列成像,并行MIP重组显示强化淋巴管,分别测量计算显影淋巴管与增强静脉的信噪比与对比噪声比,其差异采用成组t检验比较.结果40条下肢中有36个小腿段、17个大腿段见扩张淋巴管显像;其信噪比和对比噪声比分别为257±130、207±113,而静脉强化后分别为218±129、152±113,两者强化前后差异均有统计学意义(噪声比t=-2.649,对比信噪比t=-3.404,P值均<0.01).有30个肢体腹股沟区可见淋巴结强化,26个肢体存在侧副管和淋巴反流.结论MR淋巴成像无创、安全易行,能够清晰展示淋巴水肿患者淋巴管的形态改变.     

淋巴水肿的研究现状

淋巴水肿是一种进展缓慢的淋巴系统疾病。目前国内外对淋巴水肿这类淋巴回流障碍性疾病的相关报道还不多见,对淋巴水肿的病因、发病机制及病理学方面的研究还缺少充分的认识,本文就目前国内外已有的相关文献及报道,对淋巴水肿的病因病理、发病机制及其相关性疾病及治疗等方面的研究现状综述如下。     

Contrast-Enhanced MR Imaging of Lymph Nodes in Cancer Patients

The accurate identification and characterization of lymph nodes by modern imaging modalities has important therapeutic and prognostic significance for patients with newly diagnosed cancers. The presence of nodal metastases limits the therapeutic options, and it generally indicates a worse prognosis for the patients with nodal metastases. Yet anatomic imaging (CT and MR imaging) is of limited value for depicting small metastatic deposits in normal-sized nodes, and nodal size is a poor criterion when there is no extracapsular extension or focal nodal necrosis to rely on for diagnosing nodal metastases. Thus, there is a need for functional methods that can be reliably used to identify small metastases. Contrast-enhanced MR imaging of lymph nodes is a non-invasive method for the analysis of the lymphatic system after the interstitial or intravenous administration of contrast media. Moreover, some lymphotrophic contrast media have been developed and used for detecting lymph node metastases, and this detection is independent of the nodal size. This article will review the basic principles, the imaging protocols, the interpretation and the accuracies of contrast-enhanced MR imaging of lymph nodes in patients with malignancies, and we also focus on the recent issues cited in the literature. In addition, we discuss the results of several pre-clinical studies and animal studies that were conducted in our institution.     

Magnetic resonance flow measurements in real time: comparison with a standard gradient-echo technique

Ultrafast gradient systems and hybrid imaging sequences offer the opportunity to acquire phase contrast flow data in real time. In a 1.5-Tesla magnetic resonance (MR)-tomograph, peak velocity and volume flow were assessed in 36 large vessels (aorta) and 33 medium-sized vessels (carotid and iliac artery) using a real-time (segmented k-space turbo gradient-echo planar imaging sequence) in comparison with a gradient-echo technique. With the real-time technique, the matrix was reduced from 116 to 64, and temporal resolution changed from 30 msec to 124 msec. Measurements of peak velocity correlated in large (r = 0.88) and medium-sized vessels (r = 0.81). Volume flow measurements correlated in large vessels (r = 0.87), however, a poor correlation (r = 0.64) was found in medium-sized vessels. Thus, scan time can be significantly reduced and images acquired without electrocardiogram (ECG)-triggering. Flow volume can only be determined in large vessels with sufficient accuracy, mainly due to reduced spatial resolution in smaller vessels.     

Multislice first-pass myocardial perfusion imaging: Comparison of saturation recovery (SR)-TrueFISP-two-dimensional (2D) and SR-TurboFLASH-2D pulse sequences

PURPOSE: To compare signal-to-noise ratio (SNR), contrast-to-noise (CNR) ratio, and diagnostic accuracy of a newly developed saturation recovery (SR)-TrueFISP-two-dimensional (2D) sequence with an SR-TurboFLASH-2D sequence. MATERIALS AND METHODS: In seven healthy subjects and nine patients with coronary artery disease (CAD), contrast-enhanced perfusion imaging (with Gd-DTPA) was performed with SR-TrueFISP and SR-TurboFLASH sequences. Hypoperfused areas were assessed qualitatively (scale = 0-4). Furthermore, SNR and CNR were calculated and semiquantitative perfusion parameters were determined from signal intensity (SI) time curves. Standard of reference for patient studies was single-photon emission computer tomography (SPECT) and angiography. RESULTS: The perception of perfusion deficits was superior in TrueFISP images (2.6 +/- 1.0) than in TurboFLASH (1.4 +/- 0.6) (P < 0.001). Phantom measurements yielded increased SNR (143 +/- 34%) and CNR (158 +/- 64%) values for TrueFISP. In patient/volunteer studies SNR was 61% to 100% higher and signal enhancement was 110% to 115% higher with TrueFISP than with TurboFLASH. Qualitative and semiquantitative assessment of perfusion defects yielded higher sensitivities for detection of perfusion defects with TrueFISP (68% to 78%) than with TurboFLASH (44% to 59%). CONCLUSION: SR-TrueFISP-2D perfusion imaging provides superior SNR and CNR than TurboFLASH imaging. Moreover, the dynamic range of SIs was found to be higher with TrueFISP, resulting in an increased sensitivity for detection of perfusion defects.     

Differentiation of hepatocellular carcinoma and hepatic metastasis from cysts and hemangiomas with calculated T2 relaxation times and the T1/T2 relaxation times ratio

PURPOSE: To determine the diagnostic capability of the T1 and T2 relaxation times and the T1/T2 relaxation times ratio generated with the mixed turbo spin echo (mixed-TSE) pulse sequence, in order to discriminate between hepatocellular carcinoma (HCC)/metastases and hemangiomas/cysts. MATERIALS AND METHODS: A retrospective review of 36 MR examinations implementing the mixed-TSE pulse sequence demonstrated 70 focal hepatic lesions. Quantitative MR algorithms were used to generate T1 and T2 relaxation times, and the T1/T2 relaxation times ratio for each lesion. A two-sample t-test compared mean T1 and T2 relaxation times, and the T1/T2 relaxation times ratio, by lesion type: carcinoma/metastases and hemangiomas/cysts. Sensitivity and specificity for discriminating carcinoma/metastases from hemangiomas/cysts with T2 relaxation time thresholds of 112 and 125 msec, as well as a ratio of T1/T2 relaxation times of 5.8, were calculated. RESULTS: Using a T2 relaxation time threshold of 112 msec, 92% sensitivity and 100% specificity discriminating cysts/hemangiomas from HCC/liver metastasis was demonstrated. With a threshold of 125 msec, 96% sensitivity and 98% specificity was demonstrated. There was no correlation between calculated T1 relaxation times and type of lesion. Using a T1/T2 relaxation times ratio of 5.8, 100% sensitivity and specificity were demonstrated. CONCLUSION: Although there is high sensitivity and specificity associated with the use of T2 relaxation times alone to discriminate carcinoma/metastases from hemangiomas/cysts, using the T1/T2 relaxation times ratio threshold of 5.8 allowed proper classification of all lesions.     

Reproducibility of left ventricular mass measurement using a half-Fourier black-blood single-shot fast spin-echo sequence within a single breath hold: comparison with a conventional multiple breath-hold segmented gradient echo technique in patients

PURPOSE: To compare the reproducibility of left ventricular (LV) mass measurements using a black-blood half-Fourier single-shot fast spin-echo (SSFSE) and a segmented gradient echo magnetic resonance (MR) pulse sequence.MATERIAL AND METHODS: Breath-hold SSFSE and segmented gradient echo cardiac MR examinations were performed twice in 32 patients and manual detection of the LV endocardium and epicardium was applied by two blinded reviewers. The SSFSE pulse sequence allowed whole-heart coverage in a single breath hold, while multiple breath holds were required using the segmented gradient echo sequence. Spatial presaturation slabs were used with the SSFSE pulse sequence to reduce the field of view (FOV) and thereby achieve higher spatial resolution.RESULTS: Intraclass correlation coefficients were higher with the SSFSE pulse sequence than with the segmented gradient echo pulse sequence: intraobserver reproducibility reached 0.999 vs. 0.991; interobserver reproducibility: 0.997 vs. 0.981; and interstudy reproducibility: 0.998 vs. 0.936. These higher levels of reproducibility were confirmed on Bland and Altman plots.CONCLUSION: LV mass measurements can be assessed more reproducibly with the single breath-hold SSFSE technique than with the standard multiple breath-hold segmented gradient echo method.     

Zero filled partial fourier phase contrast MR imaging: in vitro and in vivo assessment

PURPOSE: To validate partial Fourier phase contrast magnetic resonance (PC MR) with full number of excitation (NEX) PC MR measurements in vitro and in vivo. MATERIALS AND METHODS: MR flow measurements were performed using a partial Fourier and a full NEX PC MR sequence in a flow phantom and in 10 popliteal and renal arteries of 10 different healthy volunteers. Average velocity, peak velocity, and flow results were calculated and compared with regression analysis. RESULTS: Excellent correlations in average velocities (r = 0.99, P < 0.001), peak velocities (r = 0.99, P < 0.001), and flow rates (r = 0.98, P < 0.001) were demonstrated in vitro between the two different acquisitions. For the popliteal arteries there was excellent correlation between peak velocities for both acquisitions (r = 0.98, P < 0.0001); the correlation of average velocity measurements when using all data points in the cardiac cycle for all volunteers was 0.96 (P < 0.001). For the renal arteries the same comparison resulted in a good correlation for average velocity (0.93, P < 0.001) and peak velocity measurements (r = 0.91, P = 0.002), although the correlation coefficient for flow rates was 0.88 (P = 0.004). Blurring of the vessel margins was consistently observed on magnitude images acquired with the partial Fourier method, causing overestimation of the vessel area and some error in the flow measurements. CONCLUSION: Partial Fourier PC MR is able to provide comparable average and peak velocity values when using 1 NEX PC MRI as a reference.     

Brain MR imaging in the evaluation of chronic headache in patients without other neurologic symptoms

RATIONALE AND OBJECTIVES: The authors investigated the use of magnetic resonance (MR) imaging of the brain in adult patients with a primary complaint of chronic headache and no other neurologic symptoms or findings and determined the yield and MR predictors of major abnormalities in these patients. MATERIALS AND METHODS: The medical records and MR images of 402 adult patients with chronic headache were retrospectively reviewed. All patients had been evaluated and referred by the neurology service. The findings were categorized as either negative or positive for major abnormality. Multivariate analysis with a linear logistic regression technique was performed on the clinical data, which included patient age, patient sex, and headache type. RESULTS: Major abnormalities were found in 15 patients (3.7%), consisting of seven women (2.4%) and eight men (6.9%). Major abnormalities were found in 0.6% of those with migraine headaches, 1.4% with tension headaches, none with mixed migraine and tension headaches, 14.1% with atypical headaches, and 3.8% with other types of headaches. Multivariate analysis showed that the atypical headache type was the most significant predictor of major abnormality. CONCLUSION: The yield of major abnormalities found with brain MR imaging in patients with isolated chronic headache is low. However, those patients with atypical headaches have a higher yield of major abnormalities and may benefit from imaging.     

Prolonged General Anesthesia in MR Studies of Rats

RATIONALE AND OBJECTIVES: Magnetic resonance (MR) imaging of laboratory animals may require general anesthesia to minimize body movements over many hours. The anesthetization technique should allow physiologic parameters to remain as close to normal as possible, permit fast recovery, allow safe, repeated use, and avoid attachment of ferrous metal components to the animal. The purpose of this study was to evaluate an anesthetization technique that was developed to meet each of these qualifications. MATERIALS AND METHODS: In 15 rats (280-483-g body weight), general anesthesia was induced (with intramuscular ketamine hydrochloride, xylazine hydrochloride, acepromazine maleate, and atropine), a tail vein catheter was inserted, and preimaging surgical procedures were performed. A face mask was applied, the animal was positioned in a dorsal recumbent position on an acrylic board, and an isothermal heating pad was placed on the ventral aspect of the abdominal wall. The rat, on the board, was then inserted into a trough that contained a custom-built, linearly polarized birdcage head coil and placed in the bore of a 4.7-T horizontal-bore magnet. The face mask was connected to a non-rebreathing gaseous anesthetic system, and anesthesia was maintained with 1.5-2.0 L/min oxygen and 0.25%-1.50% isoflurane. Oxygen saturation, heart rate, and rectal temperature were continuously monitored. RESULTS: The duration of intramuscular anesthesia was 110 minutes +/- 12, and the duration of gaseous anesthesia was 106 minutes +/- 43. The monitoring equipment permitted display of vital signs. CONCLUSION: The method appeared safe, was easy to perform, maintained a stable physiologic state for the parameters monitored, and could be used for repeated anesthesia in the same animal.