动态增强磁共振血管成像对主动脉疾病的诊断价值

目的的：评价动态增强磁共振血管成像对主动脉疾病的诊断价值及对临床治疗的指导作用。方法：82例怀疑有主动脉疾病的患者，应用动态增强磁共振血管成像技术扫描，并与手术结果和血管造影对照，分析DCEMRA的图像质量及其对血管的显示情况。结果：82例均获得满意图像。DCE、EMRA可清晰地显示主动脉疾病的位置以及血流动态情况。结论：动态增强磁共振血管成像是诊断主动脉疾病准确、快速、无创和首选的影像学检查方法，具有较高的临床应用价值。     

儿童主动脉缩窄的影像诊断与病理分类探讨

目的;报道149例先天性主动脉缩窄（CoA),评价磁共振对儿童主动脉缩窄的实际诊断价值并讨论主动脉缩窄的病理分类。材料和方法：在149例中,114例经心血管造影诊断,15例经造影增强磁共振血管成像术（CE－MRA）诊断,20例同时做了两种检查。结果：149例中,78例CoA伴有脉导管未闭,71例不伴有动脉导管未闭;在20例同时做了心血管造影和CE－MRA的病例中,CE－MRA优于心血管造影5例,心血管造影优于CE－MRA6例,无差别者9例。结论：CE－MRA能相当准确地诊断儿童先天性主动脉缩窄,主动脉缩窄需要有新的更合理的病理分类。     

复杂先天性心脏病手术后磁共振检查

目的 评价磁共振对手术后复杂先天性心脏病的诊断价值和检查技术。资料与方法 75例手术后复杂先天性心脏病作了磁共振检查，扫描序列为自旋回波T1WI序列，梯度回波电影序列和造影增强的磁共振血管成像序列。结果 75例中，法洛四联症等病变作右室流出道补片25例，其中7例补片远端吻合口狭窄，23例为Fontan或Glenn一类手术后，5例吻合口有梗阻。12例为主动脉弓病变术后，3例有残余梗阻，75例磁共振均清晰显示术后改变。结论 磁共振对手术后复杂先心病有很高的诊断价值，其中造影增强的磁共振血管成像序列必不可少。放射科医生熟悉手术方法对检查十分重要。     

三维动态增强磁共振腹部血管造影

目的：探讨三维动态增强磁共振腹部血管造影（3D-CE-MRA）成像技术和临床应用毒义。材料和方法：回顾性的分析了30例腹部3D-CE-MRA的成像技术和MRI表现。结果：全部病例显示良好。可以从不同的角度和位置上观察血管的整体形态。结论：三维动态增强磁共振腹部血管造影是腹部血管病变诊断的准确，快速，无创和首选的影像学检查方法，具有较高的临床应用价值。     

高压注射器在磁共振灌注及血管成像中的应用

目的：通过压力注射器在磁共振灌注及血管成像中的应用体会,探讨其在磁共振检查中的临床意义,方法：30例脑肿瘤患者脑灌注成像,28例血管病变患者常规增强扫描及5例冠心病患者心肌灌注成像,使用Medrad Spectris MR injector注射器经上肢大静脉进行快速大剂量对比剂团注。造影前根据病变或血管的大小,首先预设置流速,流量及注射时间,对选定某一病变区域用动脉程序行短时扫描或延迟扫描,作为对照,另12例脑肿瘤患者脑灌注成像采用手推方式注射,并对脑灌注曲线做对比分析,结果：42例脑肿瘤中30例经手术病理确诊,6例外院手术,6例本院活检穿刺,28例血管病变经IADSA证实,所有检查均获成功。脑血流灌注曲线压力注射器组优于手推组,28例血管病变血管造影像及5例心肌灌注图像均达诊断标准。结论：压力注射器可保持稳定速度,确保对比剂浓度以完成准确灌注,江可根据灌注成像及血管造影成像程序调节速度和时间,更为精确地进行上述检查。     

磁共振高压注射器在磁共振血管成像中的应用及护理

目的：评价高压注射器在磁共振血管成像中的临床应用价值及护理。材料和方法：对50例病人行磁共振血管成像增强扫描。使用高压注射器经上肢大静脉进行快速大剂量对比团注。造影前预先设置流速、流量及注射时间。结果：50例磁共振血管成像均获成功。结论：磁共振高压注射器可保持足够快的流速和流量。使磁共振血管造影效果满意。     

超快速增强三维磁共振血管成像的现状

超快速增强三维磁共振血管成像技术的关键为要在很短的时间内完成三维容积数据采集,同时要求对比剂注射总量和速度控制与成像序列的技术条件密切配合,从而保证在动脉或静脉的对比剂浓度处于高峰期时实现一次屏气成像。可广泛应用于主动脉、肺动脉、颈部血管、下肢血管的解剖形态显示和病变诊断。随磁共振技术的发展,该技术的临床应用价值不断提高,有逐渐取代有创性导管法血管造影的趋势。     

DCE MRA对主动脉夹层的诊断价值

目的　评价动态增强磁共振血管成像对主动脉夹层诊断价值及对临床治疗的指导作用。方法　 2 0例不同类型的主动脉夹层患者 ,应用动态增强磁共振血管成像技术扫描 ,并与手术结果对照 ,分析DCEMRA的图像质量及其对血管的显示情况。结果　 2 0例均获得满意图像 ,不但可清晰地显示主动脉夹层的真假腔和内膜片 ,并可确定破口大小、数量及位置以及血流动态情况。结论　动态增强磁共振血管成像是诊断主动脉夹层准确、快速、无创和首选的影像学检查方法 ,具有较高的临床应用价值     

磁共振TRICKS技术在下肢血管成像的临床应用价值

目的：探讨3．0T磁共振的时间分辨对比剂动态显像技术（TRICKS）在下肢血管成像中的应用价值。方法：对21例下肢血管疾病患者（肿瘤病变10例,血管性病变11例）行常规MRI平扫,注入对比剂后应用TRICKS技术行动态血管造影,最后行常规增强扫描,分析全部病例的图像质量和病变显示情况并与手术病理或DSA对照。结果：所有病例均顺利完成TRICKS检查,TRICKS图像动态显示了动静脉的充盈情况和动脉结构,肿瘤性病变可以清晰显示肿瘤的供血血管,血管性病变可以直观显示出畸形或迂曲的血管,所有诊断与DSA和病理诊断相符。结论：TRICKS技术是一种新的、有效的腹部至下肢血管成像方法,能够在不影响常规增强扫描的情况下动态观察血管情况,对下肢血管病变的诊断具有重要价值。     

MRCP在梗阻性黄疸诊断中的应用价值

目的：探讨磁共振胰胆管造影（MRCP）对梗阻性黄疸的诊断价值。方法：60例梗阻性黄疸患者采用重T2加权MR水成像技术，采集资源影像后做最大信号强度投影（MIP）处理。结果：60例患者经过MRCP检查均满意的显示梗阻部位及胆管扩张程度，定位诊断准确率100％，定性诊断准确率为86．7％。结论：MRCP可以直观准确地显示胆管梗阻的部位和程度，结合MR常规SE序列和胰胆管成像的原始图像所见，定性诊断准确率较高，对梗阻性黄疸的诊断是一种有效、安全、可靠的方法     

Follow-up of patients with previous treatment for coarctation of the thoracic aorta: comparison between contrast-enhanced MR angiography and fast spin-echo MR imaging

Regular follow-up is required in patients with previous intervention for coarctation of the aorta to detect recoarctation or aneurysm formation. In this study we describe the findings encountered on routine follow-up exams and we compare the use of contrast-enhanced 3D MR angiography (CE MRA) with fast spin-echo MRI (FSE) to study the thoracic aorta after previous intervention. In 51 consecutive patients previously treated for aortic coarctation, 74 MR studies of the thoracic aorta were performed during a 2-year period using CE MRA and FSE MRI. The thoracic aorta was evaluated for abnormalities of course, caliber, shape, and pathology of side branches. The CE MRA and FSE MRI studies were evaluated side by side by consensus of two reviewers evaluating which MR technique depicted the abnormalities of the thoracic aorta the best. Of 74 exams, six clinically important abnormalities were found: four aneurysms and two restenoses. Two small pseudoaneurysms were missed on the FSE studies. Contrast-enhanced MRA was judged to visualize aortic abnormalities better than FSE (47 of 74 MR studies) especially for the transverse aortic arch, coarctation site, left subclavian artery, and aortic arch configuration. For the ascending aorta and distal descending aorta, CE MRA and FSE performed equally well. Aortic diameters measured at four levels in the first 18 MRI studies showed no significant differences in diameter when measured by FSE or CE MRA (p = not significant). Clinically important abnormalities, such as aneurysm formation and restenosis, can be present years after treatment for aortic coarctation. In the regular follow-up of these patients, CE MRA may provide additional diagnostic information compared with FSE and should be included as part of the routine exam. Received: 3 April 2000; Revised: 5 July 2000; Accepted: 7 July 2000     

Time-resolved contrast-enhanced MR angiography of intracranial lesions

PURPOSE: To determine if contrast-enhanced (CE) MRI of intracranial lesions benefits from time-resolved MR angiography (MRA) during contrast agent injection. MATERIALS AND METHODS: For 126 patients with suspected intracranial lesions undergoing routine CE MRI at 3.0T (N = 88) or 1.5T (N = 38), time-resolved CE MRA (three-dimensional [3D] time-resolved imaging of contrast kinetics [TRICKS]) was performed during injection of the routine gadolinium (Gd) dose of 0.1 mmol/kg. Time to peak (TTP) enhancement of lesions as well as time to internal carotid artery (ICA), middle cerebral artery (MCA), superior sagittal sinus (SSS), and jugular vein enhancement were measured. Source and maximum intensity projection (MIP) images were reviewed to delineate the spatial relationship of lesions and the vasculature. RESULTS: In 61 patients (48%), additional important findings were detected on time-resolved MRA that were not seen on the routine CE protocol, including aneurysms (N = 6), arteriovenous malformations (N = 7), ICA stenoses (N = 2), vascular anomalies (N = 18), and relationships between lesions and vessels (N = 28). In addition, tumor TTP correlated with glioma grade (r = 0.87) and discriminated epithelial from nonepithelial meningiomas (P = 2.6 x 10(-5)). MRA added eight minutes to the total exam time. CONCLUSION: Time-resolved MRA performed during contrast agent injection adds information to the routine brain CE MRI examination of intracranial lesions with only a small time penalty and no additional risk to the patient.     

Prospective comparison of MRA with catheter angiography in the assessment of patients with aortoiliac occlusion before surgery or endovascular therapy

AIM: The purpose of this study was to evaluate the usefulness of gadolinium enhanced 3D magnetic resonance (MR) angiography (CE MRA) as an alternative to translumbar or brachial angiography in the pre-operative work-up of patients with aortoiliac occlusion. MATERIALS AND METHODS: Nineteen patients (14 men and five women; age range 45-77 years; mean 62 years), not suitable for perfemoral angiography (aortoiliac occlusion, n = 18; infected femoro-femoral graft with femoral artery pseudoaneurysm, n = 1), underwent pre-operative CE MRA and catheter angiography (translumbar, n = 5; brachial, n = 14). CE MRA was performed using a 3D fast spoiled gradient-recalled pulse sequence during the intravenous injection of 40 ml of gadolinium DTPA and a 32-s breath-hold. All patients subsequently underwent surgical (n = 13) or percutaneous transluminal (n = 6) treatment for their vascular disease. The accuracy of CE MRA was determined compared with the findings at catheter angiography taken as the gold standard. RESULTS: CE MRA gave accurate information about the occlusion, inflow and distal run-off in the majority of patients. CE MRA revealed occlusions with an accuracy of 94.7% in the aortic segment, 98.7% in the iliac segment, and 100% in the common femoral segment. The arterial segments distal to the common femoral artery were not completely visualized in four patients but CE MRA provided sufficient information to plan either surgical or percutaneous transluminal therapy in all but one patient. CONCLUSION: CE MRA is highly accurate in showing the presence and extent of aortoiliac occlusions. In our study group, CE MRA gave sufficient information in the pre-operative evaluation of aortoiliac occlusion.     

Measurements before endovascular repair of abdominal aortic aneurysms. MR imaging with MRA vs. angiography and CT

Purpose:
1) To compare measurements obtained with MR imaging (MRI)/contrast-enhanced MR angiography (CE MRA) with measurements obtained with angiography (DSA) and CT, for stent-graft sizing of abdominal aortic aneurysms (AAA). 2) To compare MRA measurements obtained with the two post processing techniques MIP (maximum intensity projection) and VRT (3D volume rendering technique). Material and Methods:
The prospective study included 20 consecutive patients with AAA identified by DSA and CT as suitable for endovascular repair. For the study, MRI/CE MRA was performed. Five measurement variables for stent-graft sizing were chosen. Comparisons were made between MRI/CE MRA, DSA and CT, and between observers. Comparisons were also made between MIP and VRT. Results:
Significantly shorter lengths were obtained with MRA-MIP than with DSA. Three out of six diameter measurements were significantly smaller on MRI/CE MRA than on DSA and CT. No significant differences were found between the observers. One diameter measurement was significantly smaller on MIP than on VRT, while the other measurements showed no significant differences. Conclusion:
The length measurements obtained with MRA-MIP were probably more correct than those with DSA. For more reliable diameter measurements with CE MRA, improvements of the technique, including VRT reconstructions and a standardized determination of the vessel boundaries, are needed.     

非梗阻性先天性主动脉弓畸形的增强MR血管造影和心血管造影诊断

目的 报道115例非梗阻性先天性主动脉弓畸形，评估心血管造影和增强磁共振血管造影术（CE MRA）等影像诊断方法的价值。方法 115例先天性主动脉弓畸形单经心血管造影诊断106例，单经CE MRA诊断2例，经上述2种方法诊断7例。结果 115例中，双主动脉弓5例，右位主动脉弓迷走左锁骨下动脉45例，左位主动脉弓迷走右锁肌下动脉33例，右弓孤立左锁骨下动脉11例，右弓左降7例，左弓右降4例，颈主动脉弓4例，其他6例。7例同时做了心血管造影与CE MRA检查的患者2种方法诊断结果均相互符合。2例只做了MRA的病例中有1例为颈主动脉弓，另1例为右位主动脉弓迷走左锁骨下动脉。结论 造影增强MRA是可靠的非创伤性诊断手段。     

肺隔离症的MRI诊断

目的：评价MRI在诊断肺隔离症中的价值。资料与方法：回顾性分析5例经手术病理证实的肺隔离症患者的MRI资料，评价其显示病变及其相关血管的能力。结果：5例病变无益闰于下肺后基底段，肺隔离症的MRI表现包括肺野内块影，伴有囊变（n=4)，支气管扩张（n-1),MRAey CE-MRA能够清楚显示源自降主动脉的异位血供（n=4)。结论：MRI是诊断肺隔离症的一种安全、有效的非创伤检查手段，能在一定程度上取代DSA。     

增强MRA在急性肺栓塞诊断中的应用

目的 评价增强磁共振血管造影（ＣＥ ＭＲＡ）诊断急性肺栓塞的价值。材料与方法 对１１例疑有急性肺栓塞的患者进行肺部ＤＳＡ和ＣＥ ＭＲＡ检查。ＣＥ ＭＲＡ检查时,嘱患者屏气,于静脉内团注钆－喷替酸葡甲胺（Ｇｄ－ＤＴＰＡ）对比剂后行肺动脉期扫描,用３Ｄ自由感应衰减的射频扰相稳态梯度召唤回波序列采集图像。所有ＣＥ ＭＲＡ图像由２位ＭＲ诊断医师独立评估,并与ＤＳＡ诊断结果对比。结果 １１例患者中,ＤＳＡ发     

获得性胸主动脉病变的MRI诊断

目的：评价ＭＲＩ对获得性胸主动脉病变的诊断价值。材料和方法：共３０例,２１例在ＧＥＶｅｃｔｒａ０．５Ｔ上行ＳＥ和ＣｉｎｅＭＲＩ检查,９例在ＧＥＳｉｇｎａ１．５Ｔ上行ＳＥ、ＣｉｎｅＭＲＩ、ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ检查。成像采用横断面、主动脉长轴和左室长轴观,部分加扫矢状面和冠状面。结果：共发现升主动脉瘤１０例、主动脉夹层１０例、主动脉扩张９例和降主动脉溃疡１例。经对照表明ＣｉｎｅＭＲＩ对合并的瓣膜病变、夹层真假腔、血栓和瘤内异常血流方式的显示较ＳＥ为佳,而ＧａｔｅｄＴＯＦ和３Ｄ动态增强ＭＲＡ对整个胸主动脉形态及头臂血管的显示最佳。结论：多种ＭＲＩ技术综合运用诊断获得性胸主动脉病变可基本达到心血管造影效果。     

32接收通道并行采集全身MR血管成像技术的临床应用初探

目的初步探讨32接收通道并行采集全身MR血管成像技术在系统性动脉病变中的临床使用价值。方法30例接受三维增强全身MR血管成像(3D CE MRA)检查。仪器为1.5 T成像仪(M agnetom Avanto,S iem ens AG)配置32个接收通道和并行采集技术。病例包括临床诊断或怀疑的周围动脉闭塞性病变(PAOD)17例,多发性大动脉炎3例,结节性多动脉炎1例,Stanford B型夹层4例以及胸和(或)腹主动脉瘤5例。共使用68个表面线圈单元包绕患者全身。3D CE MRA共分4段采集,每段视野(FOV)为375 mm×500 mm,通过自动移床分段扫描,第1~3段使用并行采集技术。对比剂用量为0.3 mmol/kg,分两相注射,前0.15 mmol/kg注射流率为1.3 m l/s,后0.15 mmol/kg注射流率为0.6 m l/s。总的扫描长度约188 cm,覆盖颈动脉到小腿动脉分支(不包括颅内动脉和冠状动脉)。分析每段动脉的图像质量、各种动脉血管病变的显示效果,并同其他影像检查对照(包括DSA 9例,CT血管造影8例,单段MRA 1例)。结果所有病例均顺利完成全身3D CE MRA检查。动脉图像质量好,平均检查时间为17.4 m in。17例PAOD患者中发现70段下肢动脉病变,其中7例3D CE MRA显示了除下肢动脉病变以外的其他部位动脉狭窄。4例血管炎患者3D CE MRA显示全身多处动脉管腔不规则、狭窄或闭塞、动脉瘤以及侧支血管。3D CE MRA还清楚显示夹层和动脉瘤的严重程度和范围。与其他血管成像技术比较,除1例3D CE MRA高估血管狭窄程度外,其他均相符合。结论配置了32个接收通道和并行采集技术的新型MR成像仪能顺利完成全身3D CE MRA检查,该法操作简便,检查时间短,在全面显示各种系统性动脉病变的临床使用方面有重要价值。     

颈位主动脉弓伴动脉瘤的MRI及MRA表现

目的：分析颈位主动脉弓伴动脉瘤的MRI及MRA表现，初步探讨两种方法对其诊断价值。方法：3例颈位主动脉弓伴动脉瘤均作MRI检查，其中1例作时间飞跃法磁共振血管成像（2-dimensional time-of-flightMRA,2DTOFMRA)检查，1例作3DDCEMRA检查，另1例同时作2DTOF MRA及3DDCEMRA检查。结果：MRI与MRA均能明确诊断颈位主动脉弓，对弓上分支血管的显示，MRA优于MRI，3DDCEMRA优于2DTOFMRA，对动脉瘤的显示，MRI与3DDCEMRA优于2DTOFMRA，结论：对于颈位主动脉弓伴动脉瘤的显示，应选用3D DCEMRA及MRI两种检查方法。