Contrast-enhanced magnetic resonance angiography of carotid arterial wall in pigs

This study was designed to investigate the effects of contrast agents on MR images of balloon-injured carotid arteries containing atherosclerotic-like lesions. We have evaluated an intravascular contrast agent, MS-325 (METASYN INC., Cambridge, MA) and an extra-vascular contrast agent, Optimark, (Mallinckrodt Medical Inc., St. Louis, MO) on MR angiograms obtained 4 weeks after balloon hyperinflation-induced injury of the left common carotid artery in 12 hypercholesterolemic minipigs. High in-plane resolution (.8 × .4 mm²), thin slice (1 mm) time-of-flight gradient echo sequences were used to acquire the MR angiographic images. Vascular lumen definition was compared before and after a single bolus intravenous injection of a contrast agent. Digital subtraction angiograms were obtained from all pigs after MR imaging. High grade stenosis developed in 1 of the 12 pigs and five pigs had complete occlusion of the injured vessel. The remaining pigs exhibited essentially no visible stenoses as assessed either by MR angiography or digital subtraction angiography. The vessel walls of the stenosed and occluded vessels were visible after the injection of either intravascular or extravascular contrast agent. Histologic analyses showed well developed neovascularization in the neointima or occlusive thrombosis. We conclude that the observed contrast-enhanced vessel wall is caused by an increased vascular supply associated with thrombosis and neointimal thickening that leads to an accumulation of contrast agent in the abnormal vessel walls after the injection of the T1-shortening paramagnetic contrast agent.     

Evaluation of the iliac arteries: Comparison of two-dimensional time of flight magnetic resonance angiography with cardiac compensated fast gradient recalled echo and contrast-enhanced three-dimensional time of flight magnetic resonance angiography

We compared dynamic contrast-enhanced three-dimensional time of flight (3DTOF) magnetic resonance angiography (MRA) with two-dimensional time of flight (2DTOF) MRA with cardiac compensated fast gradient recalled echo (C-MON) and conventional angiography (CA) when it was available. C-MON re-orders the normal data acquisition to minimize ghosting artifacts generated by pulsatile flow. The initial phase of the study involved optimization of parameters and comparison C-MON with no C=MON in eight patients and volunteers. The final phase of the study involved 53 patients who were imaged with contrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON. Thirty of these patients also had CA. In the initial phase, 2DTOF MRA with C-MON was found to be equal (n = 3) or superior (n = 5) to 2DTOF without C-MON. In the final phase, the agreement among all imaging modalities varied from substantial to almost perfect (Cohen's _K = .6-.83). The lowest agreement was using 2DTOF to evaluate the external iliac segments. The among suggested treatments varied from substantial to almost perfect for all imaging modalities (Cohen's _K = .73–93). The diagnostic efficacies of 2DTOF with C-MON and contrast-enhanced 3DTOF were high overall, with the lowest value being a specificity of 63% for one reader in the evaluation of an external iliac segment using 2DTOF. In summary, 2DTOF with C-MON helped to eliminate artifacts due to pulsatility in the iliac arterial segments. In our experience, both dynamic constrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON performed well in the evaluation of the iliac arteries. Both studies have high interobserver agreement and high diagnostic efficacy. Contrast-enhanced 3DTOF MRA should be reserved for situations in which the iliac vessels are extremely tortuous or occluded or the external iliac segments are poorly seen.     

SENSE技术在磁共振腹部动态增强血管成像中的应用

目的：探讨磁共振敏感编码技术在腹部动态增强血管成像(DcE—MRA)中的应用优势。方法：将疑有腹部血管疾病的40例患者分为二组，实验组20例使用SENSE技术扫描；另外20例为对照组，直接行DCE—MRA扫描。结果：对照组20例中，13例因患者呼吸配合好，图像清晰，其中5例显示了动、静脉不同时相，8例由于扫描时间长，得到动、静脉均显影的图像。其余7例因屏气配合不好，图像出现伪影，为诊断带来了困难。实验组20例患者由于扫描时间明显缩短，均获得了清晰且不同时相的图像。结论：sENsE技术的使用大大地缩短了扫描时间，使腹部DCE—MRA可不受呼吸影响，并能获得不同时相血管强化图像，明显改善了DcE—MRA影像的质量，提高了诊断准确性。     

The importance of adjusting for differences in proximal and distal contrast bolus arrival times in contrast-enhanced iliac artery magnetic resonance angiography

We tested the hypothesis that differences in proximal and distal contrast bolus arrival times may result in insufficient vascular signal in the distal part of the aortoiliofemoral territory with routinely used timing techniques. The difference in arrival time of the contrast medium bolus between the aorta and the common femoral arteries was measured in 14 patients undergoing magnetic resonance angiography of the aortoiliac arteries. A dual-station test bolus technique adjusting for this difference was evaluated. The variation coefficient of the signal intensity in six defined locations and signal intensities (SI) normalised to fat were calculated. Comparisons were made with findings in 13 patients examined with a fluoroscopically triggered timing technique (BolusTrak, Philips Medical Systems, Best, The Netherlands). The difference in bolus arrival time between proximal and distal vessels was 0–7 s. In 3 of 14 patients it was 5.6–7 s. There was a tendency towards a lower mean variation coefficient in the dual-station group (p=0.10). With both techniques, significantly lower SIs were measured in the femoral arteries compared with SIs in the superior part of the abdominal aorta. In two cases in the BolusTrak group, a distal vessel could not be delineated but was shown to be patent on a delayed scan. Differences in contrast medium arrival time along the vessel may be large enough to preclude visualisation of distal vessels unless there is compensation. A dual-station test bolus technique taking this into account was found to be feasible. Electronic Publication     

Time-resolved MR angiography of the upper abdomen: initial clinical experience

In this study, thirty-eight patients with a variety of upper abdominal diseases were examined with three-dimensional time-resolved MR angiography (7 sec/data set). Visualisation of arterial and venous anatomy was excellent in the majority of patients. Moreover, subtraction images could be calculated and organ perfusion could be assessed. It is concluded that this technique opens new perspectives for a comprehensive evaluation of vascular and parenchymal disease. Received: 14 April 1998; Revision received: 23 October 1998; Accepted: 9 November 1998     

Value of blood pool contrast agents in magnetic resonance angiography of the pelvis and lower extremities

Our objective was: (1) to determine the appropriate dose of new ultrasmall superparamagnetic iron oxide particles for magnetic resonance angiography (MRA). This agent comprised of a single iron oxide crystal stabilized with a carbohydrate-polyethylene glycol coat (PEG-Ferron/NC 100150 injection); (2) to determine the proper flip angle for PEG-Ferron-enhanced 3 D time-of-flight (TOF) MRA sequence; and (3) to compare the enhancement of peripheral vessels following PEG-Ferron and GdDTPA-BMA. MRA parameters were: TR/TE = 50/2.1 ms, NEX = 1, FOV = 30 × 30 × 1.8 cm, and matrix = 256 × 128 × 64. In anesthetized beagle dogs (n = 10), the effects of PEG-Ferron and GdDTPA-BMA on regional signal were monitored for 45 min and compared. The lowest dose of PEG-Ferron (0.05 mmol/kg) produced the best enhancement of primary, secondary and tertiary vessels. The flip angle 60 ° provided better enhancement than 20 ° on contrast enhanced images. Unlike GdDTPA-BMA, PEG-Ferron allowed prolonged delineation (> 45 min) of the pelvis and lower extremities circulation. PEG-Ferron provided greater Contrast-to-noise ratio CNR (80.2 ± 6.2, P < 0.05) than GdDTPA-BMA (63.5 ± 2.5). It may be possible for blood pool contrast-enhanced 3 D TOF MRA to provide valuable information for visualization of vascular tree including guiding interventions. Received 6 August 1997; Revision received 25 November 1997; Accepted 3 February 1998     

The effects of time varying intravascular signal intensity and k-space acquisition order on three-dimensional MR angiography image quality

The optimum infusion timing and k-space ordering for obtaining gadolinium-enhanced three-dimensional MR angiograms was determined through computer modeling using temporal contrast characteristics obtained from patient gadolinium infusion data. The effects of bolus timing were evaluated by varying the relationship between peak intravascular gadolinium concentration and the time at which the center of k space was acquired (t_ck) for sequential and centric acquisition techniques. Flow phantom experiments were performed to validate the theoretical computations. Gadolinium concentration at the time of central k-space acquisition determines intravascular signal intensity. Artifacts, including vessel broadening and edge ringing, depend on the order in which k space is collected and on how rapidly the gadolinium concentration changes. Artifacts are greatest when the center of k space is acquired before the intravascular gadolinium peak. Application of the optimal infusion timing results in preferential arterial enhancement with a minimum of artifacts in patients undergoing MR angiography.     

Hypogenetic lung syndrome: Functional and anatomic evaluation with magnetic resonance imaging and magnetic resonance angiography

A case of hypogenetic lung syndrome is described in which anatomic and functional information was obtained with use of ECG-triggered turbo (fast) spin-echo, cine, velocity-encoded cine, and contrast-enhanced magnetic resonance angiography (MRA) sequences. To the best of our knowledge, a complete functional and anatomic study of hypogenetic lung syndrome with MRI has not been previously reported.     

三维对比增强颈部动脉MRA动脉期及延迟期影像分析

目的：评价颈部动脉增强MRA动脉期及延迟期的临床应用价值。方法：对85例颈部3D CE-MRA图像显示的动脉形态进行分析,观察每例颈部动脉的6支血管即双侧颈总动脉、双侧颈内动脉和双侧椎动脉。扫描采用3.0TMR系统（Siemens,Trio）,使用高压注射器经肘静脉注射对比剂马根维显后动态扫描。结果：统计85例的双侧颈总动脉、颈内动脉及椎动脉共510支动脉,比较分析动脉期与延迟期就颈部动脉的形态,结果显示完全一致375支,占73.5%,不一致135支,占26.5%。增强MRA动脉期上,有95支颈动脉或椎动脉表现为轻度狭窄,占不一致135支的70.4%,而在延迟期表现为正常。表现在左侧颈总动脉起始部18支,右侧颈总动脉起始部5例,左侧椎动脉起始部38支,右侧椎动脉起始部7例,左侧颈内动脉虹吸段15支,右侧颈内动脉虹吸段12支。另有40支动脉在增强MRA动脉期图像表现为中—重度狭窄,在延迟期则表现为轻度狭窄,夸大了狭窄的程度,占不一致135支的29.6%。其中左侧颈总动脉起始部19支,右侧颈总动脉起始部2支,左侧椎动脉起始部16支,右侧椎动脉起始部3支。结论：3D CE-MRA动脉期易导致动脉的起始部及迂曲部位狭窄的假阳性或夸大狭窄程度,因此在进行3D CE-MRA时不应只进行动脉期扫描,还要进行延迟期的扫描。同时还应结合原始图像,这样才能准确评价动脉的狭窄程度。     

Need for background suppression in contrast-enhanced peripheral magnetic resonance angiography.

To determine if background suppression is beneficial for peripheral magnetic resonance angiography (pMRA), nonsubtracted, subtracted, and fat-saturated contrast-enhanced (CE) pMRA were compared in 10 patients with peripheral arterial disease. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs), as well as venous enhancement and subjective interpretability, were determined in a station-by-station fashion for each technique. In three patients X-ray angiography was available as a standard of reference. SNRs and CNRs were significantly higher for fat-saturated vs. the other two techniques (P = 0.005). Subjective interpretability was best for subtracted data sets in the lower-leg station. In the iliac station, fat-saturated data sets were considered to have significantly lower interpretability than subtracted data sets. Venous enhancement occurred significantly more often in the lower-leg station with the fat-saturated technique. The value of subtraction depends on the hardware one has available and is a useful tool if dedicated surface coils are used. Background suppression by means of magnitude subtraction leads to the best lower-leg image interpretability. Care must be taken to avoid venous enhancement in the lower-leg station when using fat saturation.     

Magnetic resonance angiography of supratentorial tumours: comparison with selective digital subtraction angiography

We compared magnetic resonance angiography (MRA) and intra-arterial digital subtraction angiography (IADSA) in the study of brain tumours and assessed the utility of gadolinium-enhanced MRA. We studied 17 patients with supratentorial brain tumors. The entire brain was imaged with multiple overlapping thin volume acquisitions. After IV injection of gadolinium-DTPA, a single thick-slab MRA acquisition was performed. Standard three-dimensional (3D-TOF) acquisitions (in six patients) and 3D-TOF with magnetization transfer prepulse and tilted optimisation nonsaturing radiofrequency excitation pulses (in 11 patients) were used. Displacement of the anterior cerebral artery, main stem and insular branches of the middle cerebral artery was seen well on unenhanced and contrast-enhanced MRA. Displacement of the lenticulostriate and anterior choroidal arteries was seen only once, after Gadolinium. Tumour encasement of the middle cerebral artery was demonstrated in one patient. Tumour vessels were seen in 2 of 8 cases before and 3 of 8 after gadolinium; Tumour hypervascularity was seen only after gadolinium, in 3 of 8 cases. Study of the veins was possible only on gadolinium-enhanced MRA. Displacement of the venous angle was seen in 4 of 7 patients in the frontal, and in all of 8 patients on the lateral projections. Early venous drainage was not seen. Patency of the dural venous sinuses was demonstrated in all patients, but in one neoplastic occlusion of a cortical vein was recognised.     

单倍剂量三维动态增强MR肾动脉造影

目的:评价单倍剂量三维动态增强MR肾动脉造影(3D DCE-MRA)的图像质量及临床应用价值。方法:60例疑肾动脉狭窄的患者,随机分为A、B两组(各30例)。预先推注1ml钆喷替酸葡甲胺(Gd-DTPA)测定对比剂循环时间,用三维快速小角度激发序列(3D FLASH)检查A、B两组患者,A组用单倍剂量Gd-DTPA(平均0.11mmol/kg体重),B组用双倍剂量Gd-DTPA(平均0.2mmol/kg体重)。比较A、B两组原始图像的信噪比和对比噪声比以及最大信号投影图像的质量。结果:A、B组的肾动脉信噪比为45.3±17.2和49.6±20.1,对比噪声比为37.6±15.6和39.7±18.5,两者差异无显著性意义(P>0.05)。两组MIP图像质量差异无显著性意义。单倍剂量3D DCE-MRA显示了12例(14条)肾动脉狭窄。结论:单倍剂量三维动态增强MR肾动脉造影图像清晰,能满足临床诊断需要。     

Pulmonary hemorrhage: Imaging with a new magnetic resonance blood pool agent in conjunction with breathheld three-dimensional magnetic resonance angiography

Purpose: To describe the three-dimensional magnetic resonance angiography (3D MRA) imaging appearance of the pulmonary arteries following administration of a superparamagnetic iron oxide blood pool agent to human volunteers, and to demonstrate in an animal model (pigs) how this technique can be used to detect pulmonary parenchymal hemorrhage. Methods: Two volunteers were examined following the intravenous administration of a superparamagnetic iron oxide blood pool agent (NC100150 Injection, Nycomed Amersham Imaging, Wayne, PA, USA). T1-weighted 3D gradient recalled echo (GRE) image sets (TR/TE 5.1/1.4 msec, flip angle 30°) were acquired breathheld over 24 sec. To assess the detectability of pulmonary bleeding with intravascular MR contrast, pulmonary parenchymal injuries were created in two animals under general anesthesia, and fast T1-weighted 3D GRE image sets collected before and after the injury. Results: Administration of the intravascular contrast in the two volunteers resulted in selective enhancement of the pulmonary vasculature permitting complete visualization and excellent delineation of central, segmental, and subsegmental arteries. Following iatrogenic injury in the two animals, pulmonary hemorrhage was readily detected on the 3D image sets. Conclusion: The data presented illustrate that ultrafast 3D GRE MR imaging in conjunction with an intravenously administered intravascular blood pool agent can be used to perform high-quality pulmonary MRA as well as to detect pulmonary hemorrhage.     

Carotid magnetic resonance angiography: improved image quality with dual 3-inch surface coils

Magnetic resonance angiography (MRA) hs inherent artifacts due to variation in velocity and direction of flowing blood in the carotid bulb and regions of stenosis. We examined the efficiency of dual 3-inch surface coils to delineate carotid artery flow better. Carotid MRA was performed on ten healthy volunteers and six patients, on a 1.5 T system. A special adapter was constructed to use with 3-inch (receive-only) coils, which were placed over the carotid bifurcations. Routine anterior neck coils were also used. Contiguous axial two-dimensional (45/8.7, 1.5 mm, flip angle 60°) time-of-flight sequences were used. Image matrix was 256×256 with two signals averaged and acquisition time 6–10 min. These images were postprocessed and reformatted into angiographic views using a maximum intensity projection algorithm. Computer simulation of carotid artery blood flow through-out the cardiac cycle based on vessel contours derived from digital subtraction angiography was carried out by finite element analysis. Improved definition of vessel margin, particularly at the carotid bifurcation, and substantially increased signal-to-background ratio of flowing blood were obtained with 3-inchcoils. Apparent loss of signal in the carotid bulb was diminished. In one patient, contiguous flow throughout a high-grade stenosis was well defined, with the surface coil method, while drop-off of signal was observed with routine neck coil imaging.     

椎动脉增强磁共振血管造影少量对比剂预注射试验分析

目的验证能否通过年龄、体重、心率等推测对比剂峰值时间,评价少量对比剂预注射试验的应用价值.方法搜集55例椎动脉增强MR血管造影（CEMRA）前少量对比剂预注射试验的有关数据,包括年龄、体重、心率、到达时间、峰值时间、持续时间、峰值信号等,所得数据利用SPSS软件进行直线相关和回归分析.结果年龄（55例,平均年龄62岁,中位年龄59岁）、体重（55例,平均体重63kg）、心率（40例,平均心率73次/min）与对比剂峰值时间（55例,平均峰值时间17.5 s）之间的相关度在α=0.05水平差异没有统计学意义（相关系数r分别为0.231、0.118、-0.046,t值分别为1.728、0.865、-0.284,P值分别为0.090、0.392、0.776）.峰值时间与峰值信号（55例,平均峰值信号472）有显著的负相关（r=-0.322,t=2.56,P=0.016）而与持续时间（49例,平均持续时间10.35 s）有显著的正相关（r=0.658,t=5.99,P=0.000）,峰值信号与体重呈显著负相关（r=-0.356,t=2.77,P=0.008）.峰值信号与峰值时间、体重的直线回归分析结果中,其标准化回归系数b分别为-0.284和-0.322,t值分别为-2.285和-2.590,P值分别为0.026和0.012.结论通过年龄、体重、心率推测对比剂峰值时间不可靠;通过少量对比剂预注射试验,能获得合适的正式扫描延迟时间,并能对正式扫描时对比剂注射流率作及时调整.     

Moving-table reduced-dose gadolinium-enhanced three-dimensional magnetic resonance angiography: velocity-dependent method with three-phase gadolinium infusion

The purpose of this study was to develop a method for reducing gadolinium dose and suppressing venous overlap in moving-table three-dimensional (3D) magnetic resonance (MR) angiography from the abdomen to the feet. Thirty-one patients underwent three-phase infusion of 16-18 mL of gadolinium: infusion rates and imaging times were determined after taking into account mean blood flow velocity, so that image acquisition was synchronized with peak arterial enhancement at both the first and third stations (velocity-dependent method). Twenty-three other patients underwent slow infusion of 38 mL of gadolinium with fixed acquisition time (high-dose method). The image quality for the two methods was compared. The velocity-dependent method produced good image quality with significantly less venous overlap than the high-dose method, especially in the below-the-knee region (P <.001). The velocity-dependent method provides satisfactory MR angiograms using 16-18 mL of gadolinium in patients having various blood flow velocities.     

Evaluation of the effects of intravascular MR contrast media (gadolinium dendrimer) on 3D time of flight magnetic resonance angiography of the body

The aims of this preliminary study were to establish the efficacy and minimum effective dose of TG₅(FdDO3A)₅₂ gadolinium dendrimer for contrast-enhanced, three-dimensional (3D) time of flight (TOF) magnetic resonance angiography (MRA) of the body. In a dose ranging study in eight rabbits (Group A), each of two animals received 0.03; 0.02; 0.01; or 0.005 mmol/kg of the agent for 3D-TOF MRA of the pelvic circulation in the axial and coronal planes. An additional nine animals (Group B) received a dose of 0.02 mmol/kg for 3D-TOF MRA of the mediastinum, abdomen or of the lower limbs. Quantitative and qualitative analyses of the images from Group A demonstrated a dose-related reduction in saturation effects and improved visualization of vascular structures, with maximal augmentation of the contrast-to-noise ratio (CNR) at 0.03 mmol/kg. The dose of 0.02 mmol/kg was found to be the minimal effective dose at the three vascular regions.     

Usefulness of black-blood magnetic resonance angiography generated from vessel wall imaging after the stent-assisted treatment of intracranial arterial diseases

PurposeAfter stent-assisted treatment for intracranial diseases, three-dimensional time-of-flight magnetic resonance angiography is a noninvasive follow-up method, but susceptibility artifacts prevent accurate evaluations of stented arteries. Sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) sequence often used for vessel wall imaging is less susceptible to susceptibility artifacts, since it is a spin-echo sequence. Hence, we evaluated the feasibility of black-blood magnetic resonance angiography generated from vessel wall imaging data obtained using the SPACE sequence in the depiction of stented arteries by comparing with three-dimensional time-of-flight magnetic resonance angiography and digital subtraction angiography.MethodsOur study group comprised 11 consecutive patients. For both three-dimensional time-of-flight magnetic resonance angiography and black-blood magnetic resonance angiography, the contrast ratio obtained from the stented artery and the normal artery proximal to the stent were calculated. And the depiction of stented arteries was visually evaluated. Additionally, the relative diameter index obtained from the stented artery and the normal artery proximal to the stent were calculated for three-dimensional time-of-flight magnetic resonance angiography, black-blood magnetic resonance angiography and digital subtraction angiography.ResultsThe contrast ratio of the stented artery was significantly lower than that of the normal artery on three-dimensional time-of-flight magnetic resonance angiography, but no significant difference was seen using black-blood magnetic resonance angiography. Regarding both the diameter index and the visual assessment score, black-blood magnetic resonance angiography was significantly better than three-dimensional time-of-flight magnetic resonance angiography. On black-blood magnetic resonance angiography, the diameter index was equal to that of digital subtraction angiography, and the flow signal was homogeneous and continuous in most the cases.     

Two-dimensional time-of-flight magnetic resonance angiography of renal arteries without maximum intensity projection: A prospective comparison with angiography in 21 patients screened for renovascular hypertension

Purpose We compared magnetic resonance angiography (MRA) with conventional angiography to establish its value as a screening test in the workup for renal hypertension.Methods Twenty one patients underwent MRA and angiography within a three day interval. Fifteen patients were suspected of having renovascular hypertension on the basis of clinical findings; the remaining six had multivessel atherosclerosis with renal insufficiency. MRA was performed on a 1 Tesla magnet in three planes: axial, coronal and perpendicular to the axis of each renal artery, by means of several contiguous or overlapping individual slice acquisitions. The two examinations were read by the same two independent observers, before and after an interval of 3 months.Results Conventional angiography showed 48 renal arteries. All main and three of six accessory renal arteries were correctly identified by MRA, as well as 11 of 14 significant stenoses or thromboses. Overreading of stenoses by MRA was observed in 4 cases. There were two false negatives for the two readers. The sensitivity and specificity of MRA for the detection of stenoses of the main renal arteries were found to be 70 and 78% respectively, for the first reading and 85 and 86% for the second reading.Conclusion MRA is considered a useful noninvasive method to determine the need for conventional angiography in patients in whom renal artery stenosis is suspected.Presented at CIRSE '92, Barcelona, Spain, 31 August 1992     

Gadofosveset trisodium-enhanced magnetic resonance angiography of the left atrium—A feasibility study

Aim

Imaging of the left atrium is regularly performed prior to pulmonary vein isolation. The aim of the study was to evaluate the feasibility of contrast-enhanced high-resolution magnetic resonance angiography (MRA) of the left atrium using the blood-pool contrast agent gadofosveset trisodium in comparison to noncontrast MRA.

Materials and methods

Twenty consecutive patients were examined by free-breathing electrocardiogram-gated whole-heart MRA (reconstructed spatial resolution, 0.7 mm × 0.6 mm × 0.8 mm) with a noncontrast T2-prepared steady state free precession sequence (T2-prep SSFP) and a gadofosveset trisodium-enhanced inversion-recovery SSFP sequence (CE IR-SSFP). Contrast-to-noise ratio (CNR) of blood in the left atrium was determined. Depiction of the left atrium was rated by two radiologists in consensus. A cardiologist segmented the MR data sets and rated depiction of the left atrium.

Results

Five of 20 patients had irregular breathing patterns with navigator efficiency less than 35% and were excluded from evaluation. CNR was significantly higher for CE IR-SSFP compared with T2-prep SSFP (18.4 ± 5.3 vs. 11.7 ± 3.5, p < 0.01). Depiction of the left atrium by T2-prep SSFP was rated as good in four patients, moderate in ten patients, and poor in one patient, whereas depiction of the left atrium by CE IR-SSFP was rated as excellent in nine patients, good in four patients, and moderate in two patients. CE IR-SSFP allowed for semiautomated segmentation of the left atrium in 15 patients, whereas T2-prep SSFP allowed for segmentation only in ten patients.

Conclusion

Gadofosveset trisodium-enhanced MRA of the left atrium is feasible with significantly improved image quality compared to noncontrast MRA.