Cranial MRI and MR angiography in Menkes' syndrome

We report two boys with Menkes' syndrome who underwent cranial MRI and MR angiography (MRA). In both, CT and MRI revealed progressive cerebral atrophy with a subdural haematoma or effusion. Delayed myelination or dysmyelination of the white matter was suggested. Tortuosity of the cervical and intracranial vessels was well demonstrated by MRA, obviating more invasive conventional angiography should it be thought necessary to demonstrate the characteristic systemic vascular changes of this syndrome.     

烟雾病MRI和MRA诊断价值(附16例报告)

目的；评价MRI和MRA对烟雾病的诊断价值。方法：分析16例烟雾病患者的MRI、MRA表现和临床资料。MRA采用三维时间飞跃法。结果：16例患者MRA检查均显示不同程度的颈内动脉分叉以上狭窄或闭塞，其中17支后交通动脉增粗，4支眼动脉增粗；16例显示基底节区异常血管网，其中6例同时显示后部异常血管网；10例显示软脑膜吻合支增多；MRI显示脑出血或脑梗塞等脑实质改变，并能显示基底节区异常血管点状流空。结论：MRI和MRA是诊断烟雾病的有效非创伤性检查方法。对该病的诊断、筛选、随访和外科5一的评价有较大价值。     

MR imaging and MR angiography of persistent trigeminal artery and its variant

Six patients with persistent trigeminal artery (PTA) and one patient with its variant (PTAV) were studied using a 1.0-T magnetic resonance unit. With both magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), four of the six PTAs were detected as abnormal connecting arteries between the cavernous internal carotids and the basilar arteries. The remaining two PTAs and one PTAV were not detected using MRI, but were imaged by MRA. It was concluded that relatively large PTAs can be detected using MRI, but small PTAs and PTAVs may be missed using MRI.     

The role of coronary CT angiography for acute chest pain in the era of high-sensitivity troponins

Accurate and efficient diagnostic triage for acute chest pain (ACP) remains one of the most challenging problems in the emergency department (ED). While the proportion of patients that present with myocardial infarction (MI), aortic dissection, or pulmonary embolism is relatively low, a missed diagnosis can be life threatening. Coronary computed tomography angiography (CCTA) has developed into a robust diagnostic tool in the triage of ACP over the past decade, with several trials showing that it can reliably identify patients at low risk of major adverse cardiovascular events, shorten the length of stay in the ED, and reduce cost associated with the triage of patients with undifferentiated chest pain. Recently, however, high-sensitivity troponin assays have been increasingly incorporated as a rapid and efficient diagnostic test in the triage of ACP due to their higher sensitivity and negative predictive value of myocardial infarction. As more EDs adopt high-sensitivity troponin assays into routine clinical practice, the role of CCTA will likely change. In this review, we provide an overview of CCTA and high-sensitivity troponins for evaluation of patients with suspected ACS in the ED. Moreover, we discuss the changing role of CCTA in the era of high-sensitivity troponins.     

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.     

Head and neck haemangiomas: contrast-enhanced three-dimensional MR angiography

We evaluated the clinical effectiveness of contrast-enhanced three-dimensional (3D) magnetic resonance angiography (MRA) for diagnosing head and neck haemangiomas. We studied six patients using a magnetization prepared rapid acquisition gradient-echo (MP-RAGE) sequence on a 1.5-T system. Conventional T1- and T2-weighted and contrast-enhanced images were also obtained. The images were compared with histological findings. In four cavernous haemangiomas, a mass was partially visible as an enhancing lesion on the early phase of MRA, and was completely visible as a larger enhancing lesion in the late phase, showing slow blood flow. In two capillary haemangiomas, a mass was completely visible in the early phase showing fast flow. In all patients, MRA clearly showed both the haemangiomas and the external carotid artery branches. MRA allowed assessment of the relationship between the haemangiomas and the feeding arteries, and of the haemodynamics. Received: 17 April 1998 Accepted: 5 June 1998     

MR imaging and angiography of cerebral venous angiomas associated with brain tumors

Summary Cervical spinal cord lesions in the anterior spinal artery syndrome were delineated on magnetic resonance images (MRI) in four patients. The lesion was always seen anteriorly in the cervical cord. On T2-weighted images, the lesions appeared hyperintense relative to the normal spinal cord, while on T1-weighted images, two chronic lesions appeared hypointense, with local atrophy of the cord. In one case, repeated T1-weighted images showed no signal abnormality 4 days after the ictus, but the lesion became hypointense 18 days later, when contrast enhancement was also recognized after injection of Gd-DTPA; this sequence of intensity changes was similar to that of cerebral infarction. The extent of the lesion seen MRI correlated closely with neurological findings in all cases. Although the findings may not be specific, MRI is now the modality of choice for confirming the diagnosis in patients suspected of having an anterior spinal artery syndrome.     

Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1±16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1±6 HU comparing right and left coronary artery and 56±9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291±65 HU in the ascending aorta, 334±93 HU in the pulmonary trunk, and 285±66 HU and 268±67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain.     

Evaluation of three-dimensional navigator-gated whole heart MR coronary angiography: the importance of systolic imaging in subjects with high heart rates

PURPOSE: To evaluate the influence of heart rate (HR) on magnetic resonance coronary angiography (MRCA) image quality in diastolic and systolic phases. MATERIALS AND METHODS: Twenty-seven healthy volunteers (9 men; 33+/-9 years, HR 53-110 bpm), were evaluated with the electrocardiography and three-dimensional navigator-gating MRCA in a 1.5-T MR scanner (Avanto, Siemens) in diastolic and systolic phases (steady-state free precession; TR/TE/flip angle=3.2 ms/1.6 ms/90 degrees). The timing of scanning was individually adapted to the cardiac rest periods obtained in the prescanning, by visually identifying when the movement of right coronary artery was minimized during diastole and systole. Images of two phases were side-by-side compared on a four-point scale (from 1=poor to 4=excellent visibility; score of 3 or 4 as diagnostic). RESULTS: Of 13 subjects with HR < or =65 bpm (low HR group, mean 59.8+/-4.9 bpm, range 53-65), the image quality scores were significantly better than that with higher heart rates (73.9+/-9.0 bpm, range 68-110) in diastolic MRCA. The image quality was significantly improved during systole in high HR group. Overall, 91.3% of low HR group had MRCA image of diagnostic quality acquired at diastole, while 88.3% of high HR group had diagnostic images at systole by segmental analysis (p=NS). CONCLUSIONS: MRCA at systole offered superior quality in patients with high heart rates.     

Two-dimensional multishot echo-planar coronary MR angiography

This work presents a two-dimensional (2D) multishot echo-planar imaging (EPI) technique for magnetic resonance angiography (MRA) of individual coronary arteries in a 17-heart-beat breath-hold. Conventional 2D and 3D segmented gradient-echo (GRE) coronary MRA requires repetitive excitation of the same slice or slab within each cardiac cycle, which can result in reduced blood signal and in motion artifacts. Two-dimensional multishot EPI can address these limitations by eliminating multiple excitations per cardiac cycle, using large flip-angle excitations, markedly reducing the data acquisition window, and performing oblique multislice 2D imaging. The goal of this study was to assess the feasibility of breath-hold 20 multishot EPI for multislice coronary MRA and to demonstrate its reliability by consistently acquiring high-quality images of the coronary arteries in a series of 16 volunteers.     

单纯含服硝酸甘油对全心导航冠状动脉MRA成像参数及图像质量影响的自身对照研究

目的:探讨单纯舌下含服硝酸甘油对全心自由呼吸导航三维采样冠脉MRA的成像参数和图像质量的影响.方法:使用自由呼吸导航三雏采样全心MR冠状动脉成像序列,对17例志愿者完成基础状态以及舌下含服硝酸甘油的MRA扫描,并进行自身对照研究,分析含服硝酸甘油对成像参数和图像质量的影响.结果:服用硝酸甘油前后受试者的心率分别为(68...     

烟雾病的MRI、MRA诊断价值

 目的探讨MRI、MRA对烟雾病(Moyamoya病)的诊断价值.方法对11例Moyamoya病患者行MRI和MRA检查,MRI包括横轴位和矢状位T1WI、T2WI、FLAIR;MRA采用3D TOF法,3例行增强MRA.结果MRI表现为:(1)Moyamoya血管:双侧3例,单侧8例;(2)脑梗死和脑软化灶11例;(3)局部脑萎缩3例.MRA表现为3例双侧颈内动脉狭窄,双侧大脑中、前动脉闭塞,大脑后动脉形成异常血管网;6例右侧颈内动脉、大脑中动脉狭窄;2例左侧颈内动脉、大脑中动脉狭窄.结论MRI能良好的显示脑内病变,MRA能较完整的显示异常血管,MRI与MRA相结合可作为烟雾病诊断的首选检查方法.     

Ultra-high-speed MR imaging

Conventional magnetic resonance imaging (MRI) has been shown to provide excellent morphological images of the body organs, particularly structures undergoing little physiologic motion. Nevertheless, the clinical usefulness of MRI has been hampered by long acquisition times, high cost of scanning because of limited patient throughput, and image artifacts due to patient motion. With recent technical developments, several ultrafast scanning techniques capable of acquiring images in a breath-hold now find their introduction into clinical use. The system improvements are potentially useful for a vast range of applications hitherto not accessible to MR imaging. Among these are functional brain imaging, realtime imaging of cardiac motion and perfusion, fast abdominal imaging, improved MR angiography, and potentially real-time monitoring of interventional procedures. Whereas some ultrafast techniques can be performed on conventional scanners, echo-planar imaging, the fastest currently available data acquisition strategy, requires specially designed hardware. This article provides on overview of the technical advances in the ultrafast MRI and discusses potential applications and the possible future impact on body scanning.Correspondence to: G. K. von Schulthess     

Acute subarachnoid Haemorrhage: 3D time-of-flight MR angiography versus intra-arterial digital angiography

To evaluate the efficacy and reliability of 3D time-of-flight MR angiography (TOF MRA) as a noninvasive procedure, 27 patients with acute subarachnoid haemorrhage (SAH) were studied with MRA immediately before or after intra-arterial digital subtraction angiography (DSA). 3DTOF MRA was performed with an axial slab of 60 mm centred on the circle of Willis and isotropic voxels. DSA showed 22 aneurysms and 1 dural arteriovenous fistula in 21 patients; the aneurysms ranged in size from 2 to 8 mm. MRA failed to show 2 small aneurysms, at the origin of the posterior and anterior communicating arteries. The 3D display of the intracranial vessels obtained with maximum intensity projection (MIP) or targetted MIP sometimes rendered the aneurysms better than DSA. However, due to its high spatial resolution, DSA more clearly defined the overall anatomy of the walls of the normal and abnormal vessels.1992 Scientific Award of the ESNR     

Differences in diagnostic evaluation and clinical outcomes in the care of patients with chest pain based on admitting service: The benefits of a dedicated chest pain unit

Background  Chest pain is one of the most common complaints of patients presenting at emergency departments. However, the most appropriate diagnostic evaluation for patients with chest pain but without acute coronary syndrome remains controversial, and differs greatly among institutions and physicians. At our institution, patients with chest pain can be admitted to an internist-run hospitalist service, a private attending service, or a cardiologist-run Chest Pain Unit. The goal of the present study was to compare the management and outcomes of patients admitted with chest pain based on admitting service. Methods  The charts of 750 patients (250 consecutive patients per service) with a discharge diagnosis of chest pain were studied retrospectively. Results  Patients admitted to the Chest Pain Unit were younger and had a lower prevalence of known coronary artery disease, hypertension, or diabetes, but a similar prevalence of other risk factors compared with the other groups. Sixty percent of the patients in the Chest Pain Unit underwent stress myocardial perfusion imaging as their primary diagnostic modality (vs 22% and 12% of patients in the hospitalist and private services, respectively; P<.001). In contrast, 35% of the patients admitted to the hospitalist service underwent rest echocardiography (vs 8% and 17% of patients in the Chest Pain Unit and private services, respectively; P<.001). Finally, 47% of the patients in the private service underwent coronary angiography as their primary diagnostic modality (vs 6% and 10% of patients in the Chest Pain Unit and hospitalist services, respectively; P<.001). The length of stay was shortest for patients in the Chest Pain Unit (1.4±1.2 days vs 3.9±3.4 days and 3.5±3.6 days in the hospitalist and private services, respectively; P<.001), even when corrected for patient age and number of risk factors. Readmission within 6 months was lowest for patients in the Chest Pain Unit (4.4% vs 17.6% and 15.2% in the hospitalist and private services, respectively; P<.001). Conclusions  The results of this study demonstrate that a highly protocolized chest pain unit, using myocardial perfusion imaging as primary diagnostic modality, results in a decreased length of stay and readmission rate.     

MR navigator-echo monitoring of temporal changes in diaphragm position: Implications for MR coronary angiography

Temporal changes in respiration could influence navigator-echo (NE)-gated MR coronary angiography (MRCA), but systematic investigation of the effects of such variations and how to limit them has not been performed. We addressed these issues by studying the influence of time in the magnet on diaphragm position and respiratory patterns using NE diaphragm monitoring in volunteers and a phantom model. NE diaphragm monitoring was performed at .5 T in 10 subjects over a total period of 35 minutes. The end-expiratory position was sustained for longer (1.1 vs .4 seconds, P < .001) and with greater position stability (SD 1.9 vs 5.9 mm, P = .01) than the end-inspiratory position. Drift of the end-expiratory position occurred over time, causing a fall in scan efficiency (44–28%, P = .01). Up-drift of the end-expiratory position was most common. Loss of scan efficiency was worse with up-drift because of loss of the end-expiratory pause from the NE window (up-drift 10% mm^?1, down-drift 7% mm^?1, both P = .03). Scan efficiency also was reduced during sleep (to a nadir of 0%), secondary to loss of the end-expiratory pause, periodic breathing with oscillating end-expiratory position, and periods of apnea. The phantom model used actual diaphragm traces to evaluate the artifact resulting from diaphragm motion during acquisition. Artifact was considerably reduced by NE adaptive motion correction compared with NE gating alone (ghosting ratio 2.0 vs 2.8, P < .01). Artifact also was significantly reduced with up-drift if scan efficiency was maintained above 35% (P = .05). For optimal NE-gated MRCA, the following features are important: the NE window should be placed around the end-expiratory position; subjects should not sleep; scan efficiency should be monitored and the NE window should be repositioned if scan efficiency falls below 35%; and adaptive motion correction should be used.     

MRI and MR angiography of persistent trigeminal artery

We describe the MRA and MR angiography (MRA) features of persistent trigeminal artery (PTA) found incidentally in eight patients, with special attention to its origin, site and course. The different patterns of posterior communicating arteries were also noted. The PTA were shown on sagittal, coronal and axial MRI and on MRA. In four cases, the PTA arose from the lateral aspect of the intracavernous internal carotid artery, ran caudally, passing round the bottom of the dorsum sellae to join the basilar artery. In the other four cases, it arose from the medial aspect, ran caudally through the sella turcica and pierced the dorsum sellae to join the basilar artery. The posterior communicating arteries were present unilaterally in five cases and bilaterally in one, and absent bilaterally in two. Identification of a PTA with a trans-sellar course is crucial if a trans-sphenoidal surgery is planned. Received: 20 September 1995 Accepted: 20 January 1996     

常规MRI联合MR脑血管成像在围产期脑后部可逆性脑病综合征中的应用研究

目的：探讨常规磁共振成像（MRI）联合MR脑血管成像在围产期脑后部可逆性脑病综合征（PRES）诊断和鉴别诊断中的应用价值。方法：5例围产期PRES患者,平均年龄为26.5岁,且均于起病后2 d内行常规MRI和MR脑血管成像,MR脑血管成像包括MR脑动脉成像（MRA）和MR脑静脉成像（MRV）。结果：病变均累及双侧顶枕叶,另累及额叶2例,基底节区2例,桥脑1例,病变占位效应不明显。病变主要位于皮层下白质,其中1例累及皮质。病变T1WI呈低、等信号,T2WI及液体衰减反转恢复序列（FLAIR）呈高信号。3例磁共振扩散加权成像（DWI）呈等信号,表观扩散系数（ADC）图为高信号,另2例部分病变DWI为高或稍高信号。增强扫描以上病变未见明确强化,MRA、MRV未见明确异常。结论：围产期RPES的MRI表现较具特征性,常规MRI联合MR脑血管成像有助于本病的早期诊断和鉴别诊断。     

MRI and MR angiography of vertebral artery dissection

A review of 4,500 angiograms yielded 11 patients with dissection of the vertebral arteries who had MRI and (in 4 patients) MR angiography (MRA) in the acute phase of stroke. One patient with incidental discovery at arteriography of asymptomatic vertebral artery dissection and two patients with acute strokes with MRI and MRA findings consistent with vertebral artery dissection were included. Dissection occurred after neck trauma or chiropractic manipulation in 4 patients and was spontaneous in 10. Dissection involved the extracranial vertebral artery in 9 patients, the extra-intracranial junction in 1, and the intracranial artery in 4. MRI demonstrated infarcts in the brain stem, cerebellum, thalamus or temporo-occipital regions in 7 patients with extra- or extra-intracranial dissections and a solitary lateral medullary infarct in 4 patients (3 with intracranial and 1 with extra-intracranial dissection). In 2 patients no brain abnormality related to vertebral artery dissection was found and in one MRI did not show subarachnoid haemorrhage revealed by CT. Intramural dissecting haematoma appeared as crescentic or rounded high signal on T1-weighted images in 10 patients examined 3–20 days after the onset of symptoms. The abnormal vessel stood out in the low signal cerebrospinal fluid in intracranial dissections, whereas it was more difficult to detect in extracranial dissections because of the intermediate-to-high signal of the normal perivascular structures and slow flow proximal and distal to the dissection. In two patients examined within 36 h of the onset, mural thickening was of intermediate signal intensity on T1-weighted images and high signal on spin-density and T2-weighted images. MRA showed abrupt stenosis in 2 patients and disappearance of flow signal at and distal to the dissection in 5. Follow-up arteriography, MRI or MRA showed findings consistent with occlusion of the dissected vessel in 6 of 8 patients. Received: 27 February 1996 Accepted: 4 June 1996     

ESWAN序列同次采集颅脑MRA及MRV

目的：探讨多回波采集T2＊WI的三维梯度回波序列（ESWAN）动脉成像（MRA）及静脉成像（MRV）的可行性。方法：11例健康志愿者均行回波数为11的ESWAN及3D-TOFMRA检查,其中7例还加做2D-TOFMRV扫描。仅保留ESWAN序列中动脉流入增强效应较强的前3个回波后处理获得的幅度图像,经最大强度投影重组Willis环图像,分析Willis环各段显示效果并与3D-TOFMRA比较;保留后7个回波的图像后处理得到的幅度图像,经最小强度投影显示颅内静脉,比较ESWAN与2D-TOFMRV对脑深部静脉的显示效果。结果：ESWAN与3D-TOFMRA对Willis环显示结果高度一致（P=1.00）,ESWAN对大脑深部静脉的显示明显优于2D-TOFMRV（P〈0.0001）。结论：合理设置ESWAN参数,可以实现同次扫描采集MRA及MRV。