肺癌肿瘤血管生成CT及MR灌注成像研究

目的:使用动态增强CT、MR灌注成像方法评价肺癌肿瘤血管生成。方法:对84 例肺癌分别进行动态增强CT和MR扫描,计算分析各动态增强CT、MRI参数及肿块增强特点,并与肺癌的微血管密度(MVD)作相关性分析。结果:CT、MR灌注影像可更直观的显示肺癌增强特点。动态增强CT各参数PH、M/A、灌注值、rBV与MVD呈正相关,其中灌注值与MVD相关性最高(r=0.758,P<0.0001),Pm值与MVD无相关性(r=0.298,P>0.05);动态增强MRI各参数SS、PH、E1、E2、E4 与肺癌MVD呈正相关,其中以SS与MVD相关性最强(r=0.874,P<0.01)。结论:CT、MRI灌注成像技术可获得较为全面的肺癌血供信息,有望成为评估肺癌肿瘤血管生成的新方法。     

肺孤立性病灶16层螺旋CT首过期灌注成像与血管生成的相关研究

目的 应用16层螺旋CT灌注成像(CTPI)技术,探讨肺孤立性病灶各灌注参数与病灶的微血管密度(MVD)、血管内皮细胞生长因子(VEGF)的相关性. 资料与方法对52例肺孤立性病灶行16层螺旋CT首过期灌注成像,利用Body-perfusion软件进行后处理,获得感兴趣区的血流量(BF)、相对血容量(rBV)、毛细血管渗透性(Pm)、达峰时间(TTP)等灌注参数.其中39例手术患者的组织标本采用免疫组织化学染色后行MVD计数和检测VEGF表达.结果 恶性组和炎性组的BF、rBV、Pm等参数均高于良性组,差异有统计学意义(P均<0.05);恶性组和炎性组仅Pm差异有统计学意义(P<0.05).良性组的TTP略高于恶性组和炎性组,但各组间差异无统计学意义(P>0.05).恶性组和炎性组的MVD、VEGF表达强度均高于良性组,差异有统计学意义(P均<0.05);但恶性组和炎性组之间MVD、VEGF表达强度的差异无统计学意义(P>0.05).除TTP外,恶性组、炎性组和良性组的BF、rBV、Pm参数值与MVD、VEGF呈正相关(P均<0.05),其中以BF与MVD、VEGF和Pm与MVD、VEGF的相关性最高.结论 肺孤立性病灶的CTPI参数与其血管生成有良好相关性,能定量地反映其血管生成情况,有助于对良恶性病灶的鉴别诊断.     

明显强化孤立肺结节血流模式的临床价值

目的利用4层螺旋CT动态增强技术定量评价不同性质的明显强化孤立肺结节的血流模式并初步评价血管内皮生长因子(VEGF)表达阳性的孤立性肺腺癌血管生成与血流模式定量CT参数的相关性.方法 78例孤立明显强化肺结节(直径≤4 cm,68例恶性,10例活动性炎性),行多层螺旋CT(MSCT)动态增强(以4 ml/s的流率注入对比剂).记录孤立肺结节增强前后各时相的CT值并计算强化值、灌注值,结节-主动脉强化值比.灌注值等于时间-密度曲线最大斜率除以主动脉强化值.其中30例VEGF表达阳性的肺腺癌患者用免疫组织化学测定微血管密度(MVD)并标定VEGF,评价肺腺癌血流模式定量CT参数(强化值、灌注值、结节-主动脉强化值比及平均通过时间)与MVD的相关性.结果恶性结节强化值(35.79±10.76) HU与活动性炎性结节(39.76±4.59) HU差异无显著意义 (t=1.148 , P=0.255).恶性结节的结节-主动脉强化值比(14.27±4.37)%及灌注值(3.02±0.96)ml-1·min-1·kg-1均低于活动性炎性结节(18.51±2.71)%,(6.34±4.39)ml-1·min-1·kg-1 (t=2.978,P=0.004;t=5.590,P<0.0001).VEGF表达阳性的肺腺癌强化值(33.06±13.57)HU、结节-动脉强化值比(14.25±4.92)%及灌注值(2.97 ±0.56) ml-1·kg-1·min-1与MVD(70.15±20.03)条/视野,均呈正相关性(r=0.781, P<0.0001;r=0.688, P<0.0001;r=0.716, P<0.0001).平均通过时间(14.86±5.84)s与MVD无显著相关性(r=0.260, P=0.200).结论恶性与活动性炎性孤立肺结节血流模式不同,恶性结节通过结节-大动脉强化值比和灌注值可有效区别于活动性炎性结节,有助于两者鉴别诊断.肺腺癌强化值、结节-动脉强化值比及灌注值反映了VEGF表达阳性的肺腺癌的MVD.强化值、结节-动脉强化及灌注值可作为VEGF相关的肺腺癌血管生成的指标.     

多层螺旋CT首过期灌注成像和肿瘤微血管密度在评价周围型肺癌TNM分期的临床价值

目的探讨多层螺旋CT首过期灌注强化指标和肿瘤微血管密度(MVD)在肺癌TNM分期的临床价值。资料与方法对32例周围型肺癌患者行CT灌注扫描,依据首过期肿块强化的时间-密度曲线(TDC)计算肿瘤的灌注强化指标,按病理结果分为:≤3 cm肺癌组和>3 cm、≤7 cm肺癌组,累及胸膜组和未累及胸膜组;有淋巴结转移组和无淋巴结转移组;TNM分期按Ⅰ~Ⅱ期和Ⅲ~Ⅳ期分两组,并对肿瘤MVD计数。各组观察指标的差异采用t检验或t’检验;将CT灌注强化指标分别与MVD做相关性分析;利用受试者工作特征(ROC)曲线分析MVD和CT灌注强化指标评价肺癌TNM分期的诊断效能。结果 (1)肿块的强化峰值(PH)、肿块与主动脉PH之比(M/A)、灌注值(PV)和MVD在肿块直径≤3 cm与>3 cm、≤7 cm之间[分别为(33.73±20.56)HU、(31.26±13.22)HU;(0.28±0.10)、(0.24±0.14);(1.58±0.83)ml.min-1.ml-1、(1.45±0.81)ml.min-1.ml-1;(73.00±15.03)个/0.74 mm2、(66.42±12.93)个/0.74 mm2]差异均无...     

周围型肺癌双源CT灌注成像与肿瘤血管生成的相关性研究

目的 探讨周围型肺癌双源CT灌注成像与肿瘤微血管密度(MVD)、血管内皮生长因子(VEGF)的关系.方法 搜集经胸部X线平片或CT平扫发现肺部肿块并行双源CT容积灌注成像,后经病理证实的周围型肺癌30例.男18例,女12例,年龄40 ～ 77岁,平均58.01岁.将CT图像传至Siemens工作站进行图像处理.计算靶层面感兴趣区(ROI)的时间-密度曲线(TDC).通过最大斜率法获得血流量(BF)、血容量(BV)、对比剂的平均通过时间(MTT)、峰值时间(TFP)和表面通透性(PS)等灌注参数及灌注图像.30例病理标本行常规HE染色病理学检查,采用免疫组织化学检测MVD计数和VEGF的表达情况.分析周围型肺癌双源CT灌注参数与MVD、VEGF表达的关系,比较周围型肺癌有无淋巴转移及与MVD、VEGF表达的关系. 结果 (1)周围型肺癌的MVD、VEGF与CT灌注参数值BF、BV呈正相关;与MTT之间无相关性,与TTP之间呈负相关,MVD与PS无相关性,VEGF与PS呈正相关.与MVD及VEGF具有相关性的CT灌注参数中以BF的相关性最高.(2)有淋巴结转移组肺癌MVD值高于无淋巴结转移组肺癌(P＜0.05);有淋巴结转移组肺癌VEGF高于无淋巴结转移组肺癌(P＜0.05).结论 双源CT灌注成像可评价周围型肺癌的肿瘤微血管生成,有助于在活体评价肿瘤血管生成.MVD、VEGF可作为评价周围型肺癌是否发生淋巴结转移的指标.     

小细胞肺癌的CT征象和血管生成(VEGF、MVD)相关性研究

目的探讨小细胞肺癌(SCLC)的CT征象和血管内皮生长因子(VEGF)、微血管密度(MVD)的相关性。方法收集资料完整的37例小细胞肺癌,回顾性分析CT征象;应用免疫组化方法(S-P法)检测标本中的VEGF、MVD的含量,统计分析其相关性。结果37例小细胞肺癌中VEGF阳性表达为83.78%(31/37)、MVD平均为51.75±16.97;VEGF阳性组MVD为53.45±13.58,VEGF阴性组MVD为39.16±15.39,2组间有差异(P<0.05);小细胞肺癌的CT征象:肿瘤直径≥3cm、分叶征、肺门纵隔淋巴结大、强化程度与MVD含量密切相关(P<0.05)。结论通过小细胞肺癌的CT征象可以评价其组织中VEGF、MVD的表达及血管生成情况,进一步判断小细胞肺癌的恶性程度、转移、预后成为可能。     

多层螺旋CT灌注成像评价周围型肺癌的血管生成及周期蛋白D1基因表达

目的 探讨多层螺旋CT灌注成像与周围型肺癌血管生成及细胞周期蛋白D1(cyclinDl)表达的相关性.方法 73例周围型肺癌行16层螺旋CT灌注成像,分析周围型肺癌的时间密度曲线(TDC)、灌注参数图像和各灌注参数[血流量(BF)、血容量(BV)、平均通过时间(MTT)、表面通透性(PS)、强化峰值(PH)、肿块-动脉强化峰值比(PHpm/PHa)].利用免疫组织化学测定微血管密度(MVD)并标定cyclinDl,评价周围型肺癌各CT灌注参数与MVD计数及cyclinD1表达的相关性.统计学方法采用单因素方差分析及Pearson相关分析方法.结果 3组周围型肺癌(腺癌、鳞癌、其他类型癌)的TDC曲线相似,都有明显的上升支,CT值明显增加[TDC曲线的峰值分别为(44.87±6.83)、(34.91±8.05)、(40.66±5.87)HU],达峰值后变化较小,较平坦,有一个平台期;cyclinD1阳性表达44例,周围型肺癌cyclinD1阳性表达患者的MVD值明显高于阴性表达者[分别为(33.88±14.81)、(23.17±11.66)条/高倍视野,P<0.01];周围型肺癌cyclinD1阳性表达者的PH、PHpm/PHa、BF、BV、PS值[分别为(60.56±6.27)HU、(20.71±2.54)、(245.54±69.73)ml·100 mg-1·min-1、(12.17±3.50)ml/100 mg、(20.11±7.34)ml·100 mg-1·min-1]明显高于阴性表达者[(56.39±6.87)HU、(19.02±3.27)、(194.23±80.89)ml·100 mg-1·min-1、(9.67±3.00)ml/100 mg、(14.10±7.45)ml·100 mg-1·min-1],差异有统计学意义(P值均<0.05);3组周围型肺癌中,cyclinD1阳性表达的PH、PHpm/PHa、BF、BV、PS值与MVD均呈正相关,其中,BV、PS、BF值的r值分别为0.409、0.517、0.503,呈显著性相关(P值均<0.01);PH、PHpm/PHa的r值分别为0.319、0.324,呈低度相关(P值均<0.05).cyclinD1阴性表达者PH、PHpm/PHa、BF、BV、PS值与MVD均无相关性.结论 多层螺旋CT灌注成像与肿瘤血管生成具有较好的相关性,能够反映肿瘤的血管生成及cyclinD1表达,提供了一种定量评价周围型肺癌血流模式的非创伤性方法,有利于周围型肺癌的诊断.     

16层螺旋CT灌注成像强化指标和肿瘤微血管密度与肺癌淋巴结转移的关系

目的 应用16层MSCT灌注成像定量评价肺癌肿瘤血管生成,并探讨CT灌注成像强化指标和肿瘤微血管密度(MVD)与肺癌淋巴结转移的关系及其价值.方法 对53例周围型肺癌行CT灌注扫描,根据首过期肿块强化的时间-密度曲线(TDC)计算肿瘤的灌注强化指标,根据病理结果分为有淋巴结转移组和无淋巴结转移组,并对肿瘤MVD计数.淋巴结转移组与无转移组各观察指标的差异采用t检验或t'检验;将CT灌注强化指标分别与MVD做相关性分析;利用ROC曲线分析MVD和CT灌注强化指标评价肺癌淋巴结转移的诊断效能.结果 (1)肺癌淋巴结转移组(26例)MVD计数高于无淋巴结转移组(27例),MVD分别为(64.69±16.34)、(42.67±16.78)个/0.74 mm~2(t=4.84,P<0.01).淋巴结转移组肿块的强化峰值(PH)、肿块与主动脉PH之比(M/A)、灌注值(PV)均高于无淋巴结转移组[PH分别为(41.79±15.50)、(29.99±10.91)HU;M/A分别为0.24±0.09、0.15±0.06;PV分别为(2.14±1.09)、(1.27±0.53)ml·min~(-1)·ml~(-1)];差异均有统计学意义(t值分别为3.21、3.95、3.66,P均<0.01).(2)PH、M/A、PV均与MVD呈正相关,其中PV与MVD的相关系数最高(r=0.716,P<0.01).(3)利用ROC曲线分析,MVD、PV判断肺癌淋巴结转移有较高的诊断价值(曲线下面积分别为0.828、0.849,P>0.05);当以MVD>52个/0.74 mm~2或PV>1.52 ml·min~(-1)·m~l(-1)作为强烈提示肺癌淋巴结转移的可能性时,其敏感性、特异性、诊断符合率均较高(分别为80.8%、81.5%、81.1%和84.6%、85.2%、84.9%).结论 CT灌注强化指标PV及MVD与肺癌淋巴结转移存在密切关系,PV可作为术前判断肺癌淋巴结转移的重要指标之一.     

周围型肺癌动态CT增强与肿瘤血管生成的相关性研究

目的　探讨周围型肺癌CT增强表现与肿瘤血管生成的关系。方法　对 43例经手术病理证实的周围型肺癌(腺癌 20例,鳞癌 23例)采用LDP免疫组化法,检测肿瘤标本中MVD和VEGF,术前均行动态CT扫描 (剂量 1. 5ml/kg,注射速率 2. 5ml/s,分别在注射造影剂后 0. 5、1、2、3、4、5min扫描),并测量感兴趣区 (ROI)CT值。结果　 (1) 43例肺癌的平均强化峰值(PA)为(35. 53±8. 68)HU,峰值时间在注射造影剂后约 2min。(2)VEGF阳性率约 63% (27 /43),MVD平均值 27.00±7. 13,肺癌的PA值与肿瘤的MVD呈正相关(rs=0.623,Ρ<0. 001 ),VEGF阳性与阴性肺癌的PA值间有显著性差异(分别为 39. 78HU±6. 88HU及 27. 64HU±4. 62HU,P<0. 001);VEGF阳性肺癌的平均PA值与MVD呈正相关 (rs=0.691,Ρ<0.001),VEGF阳性与阴性肺癌的MVD值间有显著性差异(分别为 30. 93±5. 25及 20. 38±4. 49,P<0. 001);肺癌的VEGF与MVD间呈正相关(rs=0.610,Ρ<0. 001);但肺腺癌与鳞癌的平均PA值及MVD间均无显著性差异(P>0. 05)。结论　肺癌动态CT扫描的PA值与MVD具有相关性,可作为VEGF与肿瘤血管生成相关的一个指标。     

肺腺癌血管生成与容积灌注成像:影像-病理对照

目的 初步评价肺腺癌血管生成与容积灌注成像定量CT参数的相关性.资料与方法 30例肺腺癌(直径≤3 cm)患者,行多层螺旋CT(MSCT)容积灌注成像(经肘前静脉注入非离子型对比剂).用免疫组织化学染色方法测定微血管密度(MVD)并标定血管内皮生长因子(VEGF),评价肺腺癌容积灌注成像定量CT参数(强化值、灌注值、结节-主动脉强化值比及平均通过时间)与MVD的相关性.结果 肺腺癌强化值(34.25±12.80)HU、结节-主动脉强化值比(14.59±4.72)%及灌注值(29.02 ±6.91)ml·min-1·100g-1与MVD(68.18±19.84)均呈正相关(r=0.728,P<0.0001;r=0.689,P<0.0001;r=0.894,P<0.0001).17例(56.7%)肺腺癌VEGF表达阳性,其强化值(38.16±13.88)HU、结节-主动脉强化值比(15.96 ±5.41)%、灌注值(30.91±7.25)ml·min-1·100g-1及MVD(74.36 ±20.45)均高于VEGF表达阴性的肺腺癌[(28.13±9.71)HU、(13.01±2.97)%、(26.36±5.71)ml·min-1·100g-1、60.10±11.84](t=2.10,P=0.045<0.05;t=2.30,P=0.030<0.05;t=2.51,P=0.025<0.05;t=2.78,P=0.033<0.05).VEGF表达阳性的肺腺癌强化值、结节-主动脉强化值比及灌注值与MVD均呈正相关(r=0.681,P=0.005<0.05;r=0.713,P=0.003<0.05;r=0.904,P<0.0001).结论 肺腺癌强化值、结节-主动脉强化值比及灌注值反映了肺腺癌的MVD.强化值、结节-主动脉强化值比及灌注值可能是VEGF相关的肺腺癌血管生成的指标.     

Stress MR imaging for evaluation of popliteal artery entrapment

The popliteal artery entrapment (PAE) syndrome has been recognized as a cause of arterial occlusion in young people. It is the result of an anomaly of the relationship between the popliteal artery and the gastrocnemius muscle. Eight young healthy volunteers (16 legs) and six patients (10 legs) with suspected PAE underwent magnetic resonance (MR) imaging. Gradient-echo images were obtained in axial planes with the leg at rest and during active plantar flexion against resistance. Imaging at rest allowed identification of PAE signs in only one leg, which had an anomalous medial course of the popliteal artery. In the other cases, only the stress technique was able to show signal loss in the popliteal artery due to muscular compression (two legs) or the presence of accessory muscle slip around the vessel (two legs), as confirmed at surgery. MR imaging is therefore a useful technique for the diagnosis of PAE because of its capability of combining information obtainable with other modalities.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

Uterine contractions: Possible diagnostic pitfall at MR imaging

A total of 206 nongravid patients with various gynecologic problems underwent pelvic magnetic resonance (MR) examinations that included both sagittal T2-weighted and contrast agent–enhanced T1-weighted images. MR images were retrospectively reviewed to identify changes in endometrial configuration on serial images obtained during the same MR examination. In 20 MR examinations (all in women of reproductive age), endometrial distortion due to myometrial bulging was noted on T2-weighted or contrast-enhanced T1-weighted images. It was absent on other MR images obtained at different times. Myometrial bulging exhibited low signal intensity in 18 examinations. The finding resembled adenomyosis or leiomyoma on T2-weighted or contrast-enhanced T1-weighted images. These results evidence the presence of transient myometrial bulging and transient low-intensity myometrium in the nongravid uterus. This phenomenon is thought to represent uterine contraction. Clinicians should be aware of the potential presence of transient low-signal-intensity myometrial bulging that could present diagnostic problems in the normal uterus.     

Controversies in cervical spine imaging in trauma patients

No area of emergency radiology has generated as much discussion in recent years as the subject of cervical spine imaging for trauma patients. This review will be in three parts. The first will examine the indications for cervical imaging and will focus on those factors that make patients at high risk or low risk for cervical injury. The second part will discuss the merits of radiography and computed tomography as the main screening diagnostic examination. In addition to the roles of each modality in the evaluation process, such factors as efficacy of diagnosis, time (duration) of study, and cost will be discussed. Finally, the third part will explore the methods currently employed to clear the cervical spine in comatose patients.Presented at the Annual Meeting of the American Society of Emergency Radiology, Las Vegas, Nevada, 22–25 October, 2003     

Brodie Abscess: MR imaging appearance in 10 patients

The magnetic resonance (MR) imaging features of Brodie abscess have not yet been fully evaluated. Ten patients with Brodie abscess, eight of long bone and two of vertebra, were studied with MR imaging. Long bone abscess had a characteristic “target” appearance with four layers: (a) a center with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR (short-inversion-time inversion recovery) images, (b) an inner ring isointense to muscle on T1-weighted images and with high signal intensity on T2-weighted and STIR images, (c) an outer ring hypoin-tense on all images, and (d) a peripheral halo hypointense on T1-weighted images. In six of eight cases, a soft-tissue mass was found. The two vertebral abscesses had a less specific appearance, with low signal intensity on T1-weighted images and high signal intensity on T2-weighted and STIR images. Only the peripheral halo was clearly identified in both cases.     

Dynamic contrast-enhanced MR imaging assessment of vascularized free fibular grafts

Magnetic resonance (MR) imaging may be a noninvasive method for assessing perfusion of vascularized bone grafts placed for treatment of avascular necrosis. One proximal femur of seven beagles was devascularized, with insertion of a vascularized fibular graft. MR imaging at 1 week (seven dogs) and 6 weeks (five dogs) after surgery included pre- and postcontrast spin-echo sequences, unenhanced twodimensional time-of-flight (TOF) vascular imaging, and dynamic gradient-echo imaging during infusion of gadolinium. Relative signal intensity values of selected regions obtained from the dynamic gradientecho images were plotted as percent enhancement versus time. In the operated hip, MR imaging did not show enhancement in six of seven femoral heads and greater trochanters at 1 week after surgery, with similar results after 6 weeks. MR imaging of fibular grafts 6 weeks after surgery showed an initial rapid increase in enhancement and a subsequent slower increase in five of five dogs, although no enhancement was seen in six of seven dogs at 1 week. These findings contrasted with a rapid initial increase in enhancement followed by slow decline in non-operated hips. Two-dimensional TOP imaging did not show the vascular pedicle of the graft in any dog. Findings of radionuclide bone scanning performed 1 week after surgery were consistent with devascularization of the operated femur and fibular graft. However, tetracycline distribution and histologic findings confirmed the viability of five of five grafts within the devascularized femurs 6 weeks after surgery. Thus, dynamic contrast-enhanced MR imaging at 6 weeks after surgery is valuable for assessing vascular bone graft perfusion, while similar imaging at 1 week may suggest otherwise.     

Right-side aortic arch with aneurysm of aberrant left subclavian artery: MR imaging appearance.

Reports of aneurysms of the subclavian artery in both normal and anomalous aortic arches have been rare. The authors describe a patient with a right-side aortic arch and an aneurysm of the aberrant left subclavian artery, which, to the authors' knowledge, is a previously unreported association. At presentation, the aneurysm appeared as a calcified left superior mediastinal mass. Magnetic resonance imaging enabled preoperative diagnosis and guided surgical planning.     

Adrenal tissue characterization with 0.5-T MR imaging: Value of T2*-weighted images

The authors investigated the value of magnetic resonance (MR) imaging at 0.5 T for distinguishing adrenal adenomas from adrenal metastases. The series included 23 adrenal adenomas (18 nonhyperfunctioning, five hyperfunctioning) and 23 adrenal metastases from various organs. Adrenal tumor–liver signal intensity ratios on T1-, T2-, and T2*-weighted images were calculated for adrenal tissue characterization. Adrenal adenomas were more precisely distinguished from adrenal metastases on T2*-weighted images (21 of 23, 91%) than on T2-weighted images (15 of 23, 65%). T1-weighted images were not useful for this distinction. In conclusion, T2*-weighted images were better than routine T2-weighted images for distinguishing adrenal adenomas from adrenal metastases. It can be postulated that the total signal intensity of adrenal adenomas, which contain some fat components, decreased on T2*-weighted images because of an out-of-phase effect.     

MR angiography of congenital heart disease: Value of segmented two-dimensional inflow technique and maximum-intensity-projection display

Magnetic resonance (MR) angiography of the cardiovascular system was evaluated in 41 patients with congenital heart disease by using a two-dimensional (2D) inflow technique based on a magnetization-prepared gradient-echo pulse sequence with segmented k-space data acquisition and electrocardiographic gating at 0.5 T. Inversion and saturation prepulses were used to suppress stationary tissue and enhance intravascular signal. Presaturation slabs were applied where certain vascular structures had to be suppressed. Sequence parameters were optimized by evaluating signal intensity and contrast characteristics for various flip angles and inversion and saturation delay times. The heart and intrathoracic vasculature were encompassed with 40–50 overlapping sections. Both 2D angiograms and maximum-intensity-projection images were evaluated. Combining data sets acquired in the sagittal and transverse orientations provided the most satisfactory information about the pulmonary arteries. The highest signal-to-noise ratios were obtained with a flip angle of 65° and short prepulse delay times. Two-dimensional MR angiography can provide useful diagnostic information but requires a thorough understanding of in-plane and hemodynamically induced signal intensity changes.