Accelerated Time-of-Flight Magnetic Resonance Angiography with Sparse Undersampling and Iterative Reconstruction for the Evaluation of Intracranial Arteries

OBJECTIVE: To compare the image quality of three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) with sparse undersampling and iterative reconstruction (sparse TOF) with that of conventional TOF MRA. MATERIALS AND METHODS: This study included 56 patients who had undergone sparse TOF MRA for intracranial artery evaluation on a 3T MR scanner. Conventional TOF MRA scans were also acquired from 29 patients with matched acquisition times and another 27 patients with matched scanning parameters. The image quality was scored using a five-point scale based on the delineation of arterial vessel segments, artifacts, overall vessel visualization, and overall image quality by two radiologists independently, and the data were analyzed using the non-parametric Wilcoxon signed-rank test. Contrast ratios (CRs) of vessels were compared using the paired t test. Interobserver agreement was calculated using the kappa test. RESULTS: Compared with conventional TOF at the same spatial resolution, sparse TOF with an acceleration factor of 3.5 could reduce acquisition time by 40% and showed comparable image quality. In addition, when compared with conventional TOF with the same acquisition time, sparse TOF with an acceleration factor of 5 could also achieve higher spatial resolution, better delineation of vessel segments, fewer artifacts, higher image quality, and a higher CR (p < 0.05). Good-to-excellent interobserver agreement (κ: 0.65–1.00) was obtained between the two radiologists. CONCLUSION: Compared with conventional TOF, sparse TOF can achieve equivalent image quality in a reduced duration. Furthermore, using the same acquisition time, sparse TOF could improve the delineation of vessels and decrease image artifacts.

Magnetic resonance angiography versus digital subtraction angiography in diagnosing inferior vena cava diseases of Budd-Chiari syndrome / 中华肝胆外科杂志

Objective To compare the clinical value of three-dimensional dynamic contrast enhanced magnetic resonance angiography (3D DCE MRA) and digital subtraction angiography (DSA) in diagnosing inferior vena cava diseases in suspected case of Budd-Chiari syndrome (BCS).Methods Radiological findings of 91 suspected BCS cases obtained from 3D DCE MRA and DSA in the Affiliated Hospital of Xuzhou Medical University were retrospectively analyzed.DSA test was considered as golden standard,which assess the capacity of 3D DCE MRA in diagnosing inferior vena cava diseases,including sensitivity,specificity and accuracy.Kappa test was utilized to compare the coincidence ratio of 3D DCE MRA and DSA in diagnosing inferior vena cava diseases.Results Among 91 suspected BCS cases with 3D DCE MRA,a total of 17 cases without inferior vena cava diseases were misdiagnosed as inferior vena cava stenosis,two patients with inferior vena caval obstruction was misdiagnosed as falsely negative.Seventy-two patients with 3D DCE MRA were confirmed via DSA in diagnosing inferior vena cava diseases,sensitivity was up to 97.7％ (58/60),false positivity 54.8％ (17/31),specificity 45.2％ (14/31),respectively.Fair coincidence ratio of 3D DCE MRA and DSA in diagnosing inferior vena cava diseases (Kappa =0.474,P ＜ 0.05).Conclusions There could be clinical value of 3D DCE MRA for its high sensitivity and low specificity in diagnosing inferior vena cava diseases,and favorable coincidence ratio was discovered between 3D DCE MRA and DSA.Comprehensive consideration is needed for suspected cases of inferior vena cava stenosis detected by 3D DCE MRA,and further analysis may figure out potential causes of misdiagnosis and decline false positive events.

Persistent Proatlantal Artery in Magnetic Resonance Angiography: A Case Report

Persistent proatlantal artery (PPA) is a rare embryologically remnant carotico-vertebrobasilar anastomoses. There are two types of PPA according to embryological considerations, origin and anatomic course. Type I PPA usually originate from internal carotid artery and not traversing transverse foramen. Type II PPA traverses from external carotid artery to C1 transverse foramen. The PPA is usually found incidentally without clinical symptoms, but can be related to several clinically significant vascular lesions, such as hypoplastic vertebral artery, intracranial arteriovenous malformation and in a case of carotid endarterectomy or external carotid artery embolization. So, thorough understanding of this anomaly is needed and we report a case of type II PPA diagnosed by MR angiography.

Comparison of Non-invasive Imaging Studies in the Evaluation of Carotid Artery Stenosis and Occlusion: CT Angiography, Time-of-Flight MR Angiography and Contrast-Enhanced MR Angiography

PURPOSE: We compared non-invasive imaging studies of CTA, TOF-MRA and CE-MRA to evaluate detecting internal carotid artery stenosis and occlusion. MATERIALS AND METHODS: We enrolled 20 patients with clinically suspected internal carotid artery stenosis and occlusion, or asymptomatic patient with more than 50% stenosis suspected on color Doppler ultrasonography for regular check-up. Prospectively, CTA, TOF-MRA and CE-MRA were performed, and sensitivity, specificity, positive predictive value, negative predictive value and accuracy of TOF-MRA and CE-MRA using CTA as a reference standard for detecting more than 50% stenosis were evaluated, and correlations of measured percent stenosis between 3 imaging studies were also evaluated. RESULTS: No significant difference was found between 3 imaging studies in measuring stenosis(p>0.05). Correlation coefficient was 0.932 between CTA and TOF-MRA, and 0.971 between CTA and CE-MRA. TOF-MRA had 83.3% sensitivity, 87.5% specificity, 71.4% positive predictive value, 93.3% negative predictive value and 86.4% accuracy for detecting more than 50% stenosis and occlusion. CE-MRA had 83.3% sensitivity, 93.8% specificity, 83.3% positive predictive value, 93.8% negative predictive value and 90.9% accuracy. CONCLUSION: TOF-MRA and CE-MRA provided high correlations in the evaluation of internal carotid artery stenosis and occlusion.

Brain Magnetic Resonance Angiography in Children with Chronic Headache

PURPOSE: Headaches occur frequently in the pediatric population and have a significant impact on their quality of life. Several mechanisms are currently thought to contribute to headache pathogenesis. Our aim was to investigate the association of chronic headache in children and cerebral vascular anomaly by performing brain magnetic resonance angiography (MRA). METHODS: We retrospectively reviewed medical records and MRA of 44 patients with chronic headache who visited the pediatric clinic of Young Dong Severance hospital from January 2006 to April 2008. RESULTS: The number of enrolled patients was 44. Eight(18.2%) of them showed abnormal brain MRA findings. Abnormal findings included 5 cases of unilateral A1 hypoplasia, 1 case of unilateral vertebral artery hypoplasia, 1 case of unilateral A1 and P1 hypoplasia, 1 case of Moyamoya disease. Among the 44 patients, 21 had complained only headache and 23 had complained other neurological symptoms with headache. The ratio of abnormal MRA between the two groups showed no statistical difference. CONCLUSION: Vascular anomaly could be a possible pathogenesis and risk factor in chronic headache in children. Further investigation and long term follow up is needed.

Application of 3D TOF MRA Technology in Carotid Artery Angiography / 医疗卫生装备

Objective To solve the limitation of the wide-bound imaging from aortic arch to the bifurcation of internal and external carotid artery by changing 3D TOF MRA scan parameters, and discuss the clinical value of this technology in carotid artery angiography. Methods 108 patients with cerebrovascular disease were performed with carotid artery 3D TOF MRA. Images were performed under MIP, MPR and VR. The images of bilateral common carotid arteries, external and internal carotid artery, and vertebral artery were evaluated interactively by two independent radiologists blinded to results. Results 864 blood vessels were observed with 3D TOF MRA, including 672 normal clearly, 17 unclear, 17 congenital variants, 73 un -smooth lesion, 63 vascular stenosis, 9 vascular occlusion, 5 not display, 4 depressed downward, 4 vascular enlargement. Totally,unclear, variation and lesion blood vessels were 192. The results in combination with original image analysis could meet the need of diagonosis. Conclusion 3D TOF MRA as a noninvasive and non contrast agent imaging method can be used to select the carotid stenosis and is quite good in the value of application.

The Value of MRI in Diagnosis of Aortic Aneurysm / 实用放射学杂志

Objective To investigate the diagnosis value of aortic aneurysm with MRI.Methods Two radiologist analysed 312 cases MRI of clinically suspected aortic aneurysm retrospectively,and screening 198 cases of aortic aneurysm,analysed by double blind method.Among these patients,there were 112 male and 87 female,aged 9 to 82 years(mean age of 50.4 years).86 cases underwent X-ray angiography(XRA) examination,and 79 cases with operation.Results The MRI showed 22 cases of ture aneurysm,19 of false aneurysm,127 of dissecting aneurysm,26 of Marfan′s syndrome and 4 of compound aneurysm.Contrast analysed the XRA,CT and operation,the sensitivity and accuracy of MRI is 99% and 94%.Conclusion The MRI is an accurate and safe method for detecting aortic aneurysm.

Cerebrovascular complications in autosomal dominant polycystic kidney disease(ADPKD) / 대한내과학회지

BACKGROUND: ADPKD is one of the most common hereditary renal disease in adult and is a systemic disorder with a variety of cardiovascular manifestations. To elucidate the clinical characteristics of cerebrovascular complications in Korean ADPKD patients, we reviewed the medical records of ADPKD patients who was registered in ADPKD clinic of Seoul National University Hospital. METHODS: A total of 18 adult patients were included and their sex ratio was 8:10. The median age of ADPKD diagnosis was 45.5 year (range 19-85), and age at cerebrovascular accident(CVA) was 52 years(22-82). The median duration from hypertension to CVA was 8 years(0-30). RESULTS: There were 5 cases of infarction, 4 cases of intracerebral hemorrhage, 4 cases of subarachnoid hemorrhage, and 4 cases of transient ischemic attack. Other clinical parameters of ADPKD were not different from patients who were not complicated with CVA. Intracranial aneurysms were detected in 6 patients and their median age at diagnosis was 47.5 years(33-66). Four cases were manifested as subarachnoid hemorrhage. Five cases were diagnosed through TFCA, and two of them were revealed as multiple aneurysms. Five cases received surgical treatment and five of six cases improved without any neurologic sequeale. MR angiography(MRA) were taken in 16 asymptomatic patients, and multiple aneurysms were newly detected in one of them. CONCLUSION: Cerebrovascular complications in Korean ADPKD patients were not significantly different from western patients. Intracranial aneurysms must be included in differential diagnosis in ADPKD patients who manifest an acute neurologic symptoms, and high-risk group need to be screened selectively with MRA.

A Case of Isolated Interruption of the Aortic Arch without Any Complications of Other Cardiovascular Malformations / 日本心臓血管外科学会雑誌

A 7-year-old boy suffered from isolated interruption of the aortic arch without any other complications or cardiovascular malformations. Cardiac murmur, which had been apparent since one month of age, had been left untreated because of the absence of any symptoms of heart failure. Isolated interruption of the aortic arch was noted during a routine physical examination at school and the patient was referred to our hospital for a complete medical evaluation. Blood-pressure difference was recognized not only between the right side and the left side of the upper extremities but also between the upper and lower extremities. On the basis of the results obtained via magnetic resonance angiography (MRA) and aortography, a definitive diagnosis of isolated interruption of the aortic arch was made. Reconstruction of the aortic arch by synthetic implant was indicated. The blood-pressure difference disappeared and the postoperative course was satisfactory.