Variable Significance of Brain MRI Findings in Infective Endocarditis and Its Effect on Surgical Decisions

ObjectiveTo determine how brain magnetic resonance imaging (MRI) findings impact clinical outcomes in patients with infective endocarditis (IE) and to propose a management algorithm for patients with neurologic symptoms who are candidates for valve surgery (VS).Patients and MethodsData from our center were retrospectively reviewed for patients hospitalized with IE between January 1, 2007, and December 31, 2014. Outcomes were postoperative intracerebral hemorrhage (ICH), 6-month mortality, and functional outcome at last follow-up as described by the modified Rankin Scale (mRS) score. Good outcome was defined as an mRS score of 2 or less.ResultsA total of 361 patients with IE were identified, including 127 patients (35%) who had MRI. One hundred twenty-six of 361 patients (35%) had neurologic symptoms, which prompted MRI in 79 of 127 patients (62%); 74 of 79 (94%) had acute or subacute MRI abnormalities. One patient with subarachnoid and multifocal ICH on MRI developed postoperative ICH. Patients with VS despite MRI abnormalities had lower 6-month mortality (odds ratio [OR], 0.17; 95% CI, 0.06-0.48; P<.001) and better functional outcome (OR, 4.43; 95% CI, 1.51-13.00; P=.005). Irrespective of VS, lobar or posterior fossa ICH on MRI was associated with 6-month mortality (OR, 3.58; 95% CI, 1.22-10.50; P=.02) and territorial ischemic stroke was inversely associated with good mRS (OR, 0.29; 95% CI, 0.13-0.66; P=.002). In neurologically asymptomatic patients who had VS, MRI findings did not impact 6-month mortality or functional outcomes.ConclusionMagnetic resonance imaging detects a large number of abnormalities in patients with IE. Preoperative lobar hematoma and large territorial stroke determine outcome irrespective of VS. When indicated, VS increases the odds of a good outcome despite MRI abnormalities.     

CTA与MRA在头颈部动脉狭窄中的诊断比较及符合率观察

目的:探讨对头颈部动脉狭窄使用CTA与MRA诊断的效果。方法:对2019年1月-2019年12月一年时间内进行回顾性分析,选择63例我院收治的手术病理确诊为头颈部动脉狭窄的患者,对所有患者进行CTA与MRA诊断,分析CTA诊断、MRA诊断以及CTA联合MRA诊断的准确率,动脉狭窄程度检出率,以及图像的质量。结果:CTA联合MRA诊断头颈部动脉狭窄的准确率比CTA诊断、MRA诊断均较高(P<0.05),且CTA与MRA诊断没有差异(P>0.05),CTA联合MRA诊断头颈部动脉狭窄程度的准确率比CTA诊断、MRA诊断均较高(P<0.05),且CTA与MRA诊断没有差异(P>0.05),CTA与MRA诊断的图像质量没有差异(P>0.05)。结论:对头颈部动脉狭窄使用CTA与MRA诊断,可明确判断狭窄程度,诊断准确率高,图像清晰,为临床治疗提供依据,具有较高的临床诊断价值。     

Perforator flap magnetic resonance angiography for reconstructive breast surgery: A review of 25 deep inferior epigastric and gluteal perforator artery flap patients

Purpose

To evaluate the accuracy of magnetic resonance angiography (MRA) for preoperative mapping of rectus and gluteal muscle perforating arteries prior to autologous flap breast reconstruction.

Materials and Methods

Preoperative MRA on 25 consecutive patients undergoing perforator artery‐based autologous breast reconstruction was performed at 1.5 T using 3D liver accelerate volume acquisition (LAVA) of abdominal or gluteal regions acquired during injection of 20 mL of gadobenate dimeglumine with bolus timing optimized using MR fluoroscopy or SmartPrep. Perforator artery size and coordinates relative to umbilicus or top of gluteal crease on 3D MRA were compared to findings at surgery. Reconstructed breast volume estimates from MRA were also compared to weights at harvesting.

Results

In all, 132 perforator arteries were found at surgery to be located within 1 cm of the coordinates measured on MRA and were surgically verified to be suitable for flap perfusion. Surgery verified the arterial course and caliber through the rectus and gluteal muscles visualized on MRA in 48 of 49 arteries. Volume rendering of 3D MRA predicted a breast reconstruction volume with a mean difference of 47 g compared to measurements at harvesting.

Conclusion

MRA accurately maps rectus and gluteal muscle perforator arteries for preoperative planning of autologous flaps for breast reconstruction. J. Magn. Reson. Imaging 2010;31:1176–1184. © 2010 Wiley‐Liss, Inc.     

颈动脉体瘤的MRI诊断

目的:颈动脉体瘤为少见的头颈部肿瘤。将我院4例5个瘤体的MRI资料分析,评价其诊断价值。方法:回顾性分析我院经手术病理证实的颈动脉体瘤4例,从临床信息采集、MRI检查方法到影像诊断的方式进行分析,得出结论。结果:MRI结合MRA完全可以满足颈动脉体瘤的诊断要求,基本可以取代选择性颈动脉造影对该病的诊断。结论:MRI结合MRA完全可以满足颈动脉体瘤的诊断要求,基本可以取代选择性颈动脉造影对该病的诊断。     

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.     

"Soap-Bubble" visualization and quantitative analysis of 3D coronary magnetic resonance angiograms.

In order to compare coronary magnetic resonance angiography (MRA) data obtained with different scanning methodologies, adequate visualization and presentation of the coronary MRA data need to be ensured. Furthermore, an objective quantitative comparison between images acquired with different scanning methods is desirable. To address this need, a software tool ("Soap-Bubble") that facilitates visualization and quantitative comparison of 3D volume targeted coronary MRA data was developed. In the present implementation, the user interactively specifies a curved subvolume (enclosed in the 3D coronary MRA data set) that closely encompasses the coronary arterial segments. With a 3D Delaunay triangulation and a parallel projection, this enables the simultaneous display of multiple coronary segments in one 2D representation. For objective quantitative analysis, frequently explored quantitative parameters such as signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); and vessel length, sharpness, and diameter can be assessed. The present tool supports visualization and objective, quantitative comparisons of coronary MRA data obtained with different scanning methods. The first results obtained in healthy adults and in patients with coronary artery disease are presented.     

Single breath-hold extended free-breathing navigator-gated three-dimensional coronary MRA

PURPOSE: To acquire the center of k-space while extending three-dimensional free-breathing navigator-gated coronary magnetic resonance (MR) angiography by an initial single breath-hold. MATERIALS and METHODS: This approach was successfully applied in eight healthy adult subjects. Resulting images were compared with conventionally acquired free-breathing navigator-gated MR angiograms. RESULTS: The acquisition of k-space center during the single breath-hold resulted in a 26% increase (P < 0.05) of signal-to-noise ratio. Visible length of the right coronary artery, as well as contrast-to-noise ratio between the blood and the myocardial muscle, were identical. CONCLUSION: The breath-hold extension was shown to be a valuable technique that may be combined with first-pass contrast-enhanced MR imaging.     

Combined time-resolved and high-spatial-resolution 3D MRA using an extended adaptive acquisition

PURPOSE: To combine the benefits of time-resolved dynamic imaging and single elliptical centric acquisitions in a reasonable scan time. MATERIALS AND METHODS: A time series of images with moderate spatial resolution was acquired using the 3D Time-Resolved Imaging of Contrast KineticS (3D TRICKS) technique with elliptical centric encoding during contrast arrival. Following venous opacification, a complete large centrically encoded k-space volume was acquired. The high-spatial-frequency portions of this volume were combined with a 3D TRICKS time frame to form a high-resolution image. An additional single image is formed by suppressing background and signal averaging all acquired data, including post-venous low-spatial-frequency data. For this image, 2D temporal correlation analysis is used to suppress low-spatial-frequency vein contributions. Arrival time and spatial correlations are used to suppress background. RESULTS: The 3D TRICKS time frame may be selected to ensure a combined high-resolution image that has optimal central k-space sampling for any vascular region. The single image formed by signal averaging all acquired data has increased contrast-to-noise (CNR) and signal-to-noise (SNR) ratios. CONCLUSION: The advantages of time-resolved and high-spatial-resolution imaging were combined using an extended dual-phase acquisition. Some SNR and CNR gain was achieved by signal averaging. This process is facilitated by background and vein suppression.