磁共振成像和磁共振血管造影对颈动脉间隙肿瘤诊断价值分析

目的　探讨无创性磁共振成像 (MRI)和磁共振血管造影 (MRA)对颈动脉间隙肿瘤的诊断价值 ,及其对术前制定手术方案的作用。方法　对临床可疑或确诊为颈动脉间隙肿瘤的 2 6例患者进行了术前颈部MRI和MRA检查 ,观察病变的形态、边界、内部信号 ,病变与颈动脉、分支动脉和颈内静脉的关系 ,以及颈总动脉分叉角度。结果　在 2 2例经手术或活检病理证实的患者中 ,颈动脉体瘤14例 (15个 ) ,颈动脉瘤 4例 ,神经鞘瘤 3例 ,转移性低分化鳞状细胞癌 1例。另有 4例经MRI和MRA检查及临床随访证实 ,3例为一侧较对侧明显增粗的颈总动脉 ,1例为迂曲走行的颈总动脉。MRI结合MRA检查对本组颈动脉体瘤和颈动脉瘤术前诊断均正确 ,并且MRI、MRA原始像及MRA三维重建像可提供准确的肿瘤与颈动脉及分支的关系。结论　无创性MRI和MRA检查对颈动脉间隙肿瘤 ,特别对颈动脉体瘤和颈动脉瘤的诊断优于其他检查方法 ,可以替代以往所必须进行的有创性颈动脉造影。     

Value of a contrast agent in equivocal carotid ultrasound studies: Pictorial essay

The aim of the present study was to assess the use of an echo‐enhancing agent (Levovist; Schering AG) in equivocal carotid bifurcation ultrasound studies and compare the information obtained with digital subtraction angiography (DSA). Contrast‐enhanced carotid ultrasound studies were performed on 30 carotid bifurcations in 28 patients. The standard carotid ultrasound examinations were considered equivocal for two reasons: apparent acute internal carotid artery occlusions (n = 10), and possibly patent but critically stenosed internal carotid arteries with the residual flow lumen being incompletely visualized (n = 20). All patients underwent subsequent carotid digital subtraction angiography. All patients with apparent acute carotid occlusions (n = 10) were correctly characterized on contrast‐enhanced ultrasound when compared with DSA. The majority were complete occlusions (n = 8) although in two cases there were critical carotid stenoses requiring surgical endarterectomy. In the ‘incompletely visualized lumen’ group (n = 20), the majority (n = 16) were correctly characterized on contrast enhanced ultrasound: 13 cases of critically stenotic but patent internal carotid arteries, two cases without a haemodynamically significant stenosis and one case of a carotid occlusion with patent vasa vasorum. One of the critical carotid stenoses was prospectively reported as occluded on the ‘gold standard’ angiography. In three cases the flow lumen was still incompletely visualized due to calcified plaque despite an echo‐enhancing agent; angiography revealed no significant stenosis in all cases. There was one false negative for internal carotid occlusion. This occurred early in the series and could be considered to be a technical error. Importantly, there were no false positives for carotid occlusion. Contrast‐enhanced carotid ultrasound significantly improves diagnostic confidence in equivocal carotid ultrasound studies. In appropriate clinical settings this may reduce the need for subsequent carotid angiography.     

颈动脉体瘤的DSA诊断

目的 加深对颈动脉体瘤DSA表现特点的认识，探讨其诊断与介入治疗价值。方法 由两名有经验的放射学医师按双盲法对12例动脉体瘤的DSA造影资料进行回顾性分析，然后共同讨论并达成一致意见。结果 DSA均能明确诊断。所有患者均见颈动脉分叉角度增大，颈内、外动脉移位；大部分瘤体以颈外动脉供血为主，血供较丰富；6例患者瘤体包绕颈动脉者可见局部血管受侵。2例患者栓塞后造影见肿瘤染色范围缩小，且术中出血明显减少。结论 DSA是颈动脉体瘤的诊断和术前评估的有效手段。术前栓塞有利于减少术中出血。     

颈动脉体瘤的DSA诊断

目的加深对颈动脉体瘤 DSA 表现特点的认识,探讨其诊断与介入治疗价值。方法由两名有经验的放射学医师按双盲法对12例动脉体瘤的 DSA 造影资料进行回顾性分析,然后共同讨论并达成一致意见。结果 DSA 均能明确诊断。所有患者均见颈动脉分叉角度增大,颈内、外动脉移位;大部分瘤体以颈外动脉供血为主,血供较丰富; 6例患者瘤体包绕颈动脉者可见局部血管受侵。2例患者栓塞后造影见肿瘤染色范围缩小,且术中出血明显减少。结论 DSA 是颈动脉体瘤的诊断和术前评估的有效手段。术前栓塞有利于减少术中出血。     

Combining stereotactic angiography and 3D time-of-flight magnetic resonance angiography in treatment planning for arteriovenous malformation radiosurgery

Purpose: This study was initiated to evaluate the advantages of using three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA), as an adjuvant to conventional stereotactic angiography, in obtaining three-dimensional information about an arteriovenous malformation (AVM) nidus and in optimizing radiosurgical treatment plans.

Methods and Materials: Following angiography, contrast-enhanced MRI and MRA studies were obtained in 22 consecutive patients undergoing Gamma Knife radiosurgery for AVM. A treatment plan was designed, based on the angiograms and modified as necessary, using the information provided by MRA. The quantitative analysis involved calculation of the ratio of the treated volume to the MRA nidus volume (the tissue volume ratio [TVR]) for the initial and final treatment plans.

Results: In 12 cases (55%), the initial treatment plans were modified after including the MRA information in the treatment planning process. The mean TVR for the angiogram-based plans was 1.63 (range 1.17–2.17). The mean coverage of the MRA nidus by the angiogram-based plans was 93% (range 73–99%). The mean MRA nidus volume was 2.4 cc (range 0.6–5.3 cc). The MRA-based modifications resulted in increased conformity with the mean TVR of 1.46 (range 1.20–1.74). These modifications were caused by MRA revealing irregular nidi and/or vascular components superimposed on the angiographic projections of the nidi. In a number of cases, the information from MRA was essential in defining the nidus when the projections of the angiographic outlines showed different superior and/or inferior extent of the nidus. In two cases, MRA revealed irregular nidi, correlating well with the angiograms and showed that the angiographically acceptable plans undertreated 27% of the MRA nidus in one case and 18% of the nidus in the other case. In the remaining 10 cases (45%), both MRI and MRA failed to detect the nidus due to surgical clip artifacts and the presence of embolizing glue.

Conclusions: The 3D TOF MRA provided information on irregular AVM shape, which was not visualized by angiography alone, and it was superior to MRI for defining the AVM nidus. However, when imaging artifacts obscured the AVM nidus on MRI and MRA, angiography permitted detection of AVM. Utilizing MRA as a complementary imaging modality to angiography increased accuracy of the AVM radiosurgery and allowed for optimal dose planning.     

Comparison of imaging modalities for the accurate delineation of arteriovenous malformation, with reference to stereotactic radiosurgery

PURPOSE: To investigate the discrepancy between the arteriovenous malformations seen on magnetic resonance angiography (MRA) and on stereotactic digital subtracted angiography (DSA). METHODS AND MATERIALS: The target volume on stereotactic DSA (V(DSA)) and the target volume on MRA (V(MRA)) were separately delineated in 28 intracranial arteriovenous malformations. The coordinates of the center and the outer edges of V(DSA) and V(MRA) were calculated and used for the analyses. RESULTS: The standard deviations (mean value) of the displacement of centers of V(MRA) from V(DSA) were 2.67 mm (-1.82 mm) in the left-right direction, 3.23 mm (-0.08 mm) in the anterior-posterior direction, and 2.16 mm (0.91 mm) in the craniocaudal direction. V(MRA) covered less than 80% of V(DSA) in any dimensions in 9 cases (32%), although no significant difference was seen in the target volume between each method, with a mean value of 11.9 cc for V(DSA) and 12.3 cc for V(MRA) (p = 0.948). CONCLUSION: The shift of centers between each modality is not negligible. Considering no significant difference between V(DSA) and V(MRA), but inadequate coverage of the V(DSA) by V(MRA), it is reasonable to consider that the target on MRA might include the feeding artery and draining vein and possibly miss a portion of the nidus.     

Delineation of brain AVMs on MR-Angiography for the purpose of stereotactic radiosurgery

PURPOSE: To assess the dosimetric consequences of brain arteriovenous malformation (bAVM) delineation on magnetic resonance angiography (MRA) for the purpose of stereotactic radiosurgery. METHODS AND MATERIALS: Three observers contoured a bAVM in 20 patients, using digital subtraction angiography (V(DSA)) and three-dimensional time-of-flight MRA (V(MRA)). Displacement between contours was calculated. Agreement and differences between observers and imaging modalities were assessed. A standardized treatment plan with dynamic conformal arcs was generated and dosimetric coverage of all contours and the volume of normal brain tissue within the high dose region was determined. RESULTS: The generalized reliability coefficient was "fair" for target volume (0.79), but "poor" for displacement (0.35). V(MRA) was larger than V(DSA) (5.0 vs. 4.0 mL, p = 0.001). No difference in displacement was found (2.8 vs. 2.5 mm, p = 0.156). Dosimetric coverage of V(MRA) was 62.9% (95% CI, 56.9-68.8) when V(DSA) was used as planning target volume, and coverage of V(DSA) was 83.5% (95% CI, 78.1-88.8) when V(MRA) was used for planning (p < 0.001). The mean volume of normal brain within the 80% isodose was larger when the bAVM was delineated on MRA (0.7 vs. 1.0 mL (p = 0.02) for targets < or =3 mL and 3.7 vs. 7.0 mL (p = 0.01) for targets >3 mL). CONCLUSIONS: Brain arteriovenous malformations delineated on MRA are larger and more randomly displaced. However, for bAVMs < or =3 mL, the difference in volume of normal brain tissue within the high-dose region does not seem to be clinically relevant. Therefore, MRA-images might be used as the sole imaging modality for the radiosurgical treatment of bAVMs < or =3 mL when the bAVM is located in a noneloquent position.     

TUMORS INVADING PARAPHARYNGEAL SPACE : REFINED IMAGING DIAGNOSIS

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Comparison of Duplex Ultrasound with Angiography in Assessment of Carotid Bifurcation Disease

This is a study comparing duplex ultrasound against the “gold standard” of angiography in assessing atherosclerotic disease of the carotid bifurcation, prior to prospective endarterectomy surgery. Thirty-nine patients were studied with both sonography and angiography studies being performed within one month of each other. Plaques were described by sonography as being “smooth” or “irregular” in surface and “homogeneous” or “heterogeneous” in composition. Ultrasound showed an overall 92% sensitivity, against the standard of angiography, in its ability to assess the degree of internal carotid stenosis. There was only a 63% sensitivity with the common carotid arteries and only a 65% sensitivity with the external carotid arteries. Ultrasound did not show a high accuracy in detecting plaque ulceration when compared against angio-graphy.     

Doppler Flow Measurements in the Assessment of Carotid Artery Stenosis

This study aimed to determine if the structural changes found in intravenous digital subtraction angiography (IV-DSA) studies of the extracranial carotid arteries can be related to changes in carotid blood flow, as measured by an ultrasonic Quantitative Volume Flow Meter (QFM), and tiiereby enable the elimination of normal patients from uneccesary IV-DSA. QFM blood flow measurements were performed on patients referred for investigation of suspected extracranial carotid artery disease by IV-DSA. The blood flow and velocity, high to low flow ratio, and ^velocity difference of both carotid arteries in each patient were determined, and the correlation between these values, individually and combined, and the results obtained from DSA, were determined. Analysis of results for individual arteries indicated only a weak correlation between blood flow values alone and carotid artery morphology. However, if a combination of the Dop-pler parameters was used, the sensitivity of the QFM greatly increased. The QFM was able to identify correctly 36% of the 50 patients referred for IV-DSA as having insignificant disease, and therefore it may have value as a first line of investigation in the selection of patients for IV-DSA.     

Incorporate imaging characteristics into an arteriovenous malformation radiosurgery plan evaluation model

PURPOSE: To integrate imaging performance characteristics, specifically sensitivity and specificity, of magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) into arteriovenous malformation (AVM) radiosurgery planning and evaluation. METHODS AND MATERIALS: Images of 10 patients with AVMs located in critical brain areas were analyzed in this retrospective planning study. The image findings were first used to estimate the sensitivity and specificity of MRA and DSA. Instead of accepting the imaging observation as a binary (yes or no) mapping of AVM location, our alternative is to translate the image into an AVM probability distribution map by incorporating imagers' sensitivity and specificity, and to use this map as a basis for planning and evaluation. Three sets of radiosurgery plans, targeting the MRA and DSA positive overlap, MRA positive, and DSA positive were optimized for best conformality. The AVM obliteration rate (ORAVM) and brain complication rate served as endpoints for plan comparison. RESULTS: In our 10-patient study, the specificities and sensitivities of MRA and DSA were estimated to be (0.95, 0.74) and (0.71, 0.95), respectively. The positive overlap of MRA and DSA accounted for 67.8% +/- 4.9% of the estimated true AVM volume. Compared with plans targeting MRA and DSA-positive overlap, plans targeting MRA-positive or DSA-positive improved ORAVM by 4.1% +/- 1.9% and 15.7% +/- 8.3%, while also increasing the complication rate by 1.0% +/- 0.8% and 4.4% +/- 2.3%, respectively. CONCLUSIONS: The impact of imagers' quality should be quantified and incorporated in AVM radiosurgery planning and evaluation to facilitate clinical decision making.     

Follow up of coiled intracranial aneurysms with standard resolution and higher resolution magnetic resonance angiography

Time-of-flight magnetic resonance angiography is a non-invasive alternative to digital subtraction angiography (DSA) for follow up of coiled intracranial aneurysms. Standard cranial MRA protocols are a compromise between spatial resolution and imaging time. This study compares a standard resolution MRA protocol with a protocol at higher spatial resolution MRA (HR-MRA) in 21 follow-up occasions in 17 coiled aneurysms in 15 patients. Images were reviewed for presence of residual or recurrent aneurysm and compared with DSA as the gold standard. Aneurysm flow signal on standard resolution MRA differed significantly from HR-MRA in 6/21 cases (P = 0.02) and DSA in 6/21 cases (P = 0.02). HR-MRA had 100% concordance with DSA (P = 1.0). In this study, three-dimensional time-of-flight magnetic resonance angiography carried out at standard resolution is inadequate for follow up of coiled intracranial aneurysms. HR-MRA is comparable to DSA for detection of aneurysm recurrence.     

Contrast‐enhanced three‐dimensional fast‐spoiled gradient magnetic resonance angiography of the renal arteries for potential living renal transplant donors: A comparative study with digital subtraction angiography

Preoperative assessment of the arterial anatomy of prospective renal donors is essential. Various non‐invasive techniques are used for such evaluation. We conducted this study using contrast‐enhanced 3‐D fast‐spoiled gradient (CE 3‐D FSPGR) magnetic resonance angiography (MRA) on a 1.0 Tesla magnet, for preoperative definition of the renal arteries. Forty‐five preoperative living renal donors underwent CE 3‐D FSPGR MRA of the renal vessels and the results were compared with conventional digital subtraction angiography (DSA). The renal vascular anatomy, both normal and with variations, was satisfactorily defined in all 45 cases with CE 3‐D FSPGR MRA. Fifteen cases showed an accessory or aberrant arterial supply. A small aneurysm was shown in one case. All cases compared well with conventional DSA. Our study revealed that CE 3‐D FSPGR MRA on a lower field strength magnet is accurate in defining the renal vascular anatomy and its variations.     

The inter‐sonographer reliability of carotid duplex ultrasound

Carotid duplex ultrasound (CDUS) is a non‐invasive technique used to assess the severity of carotid artery stenosis. It has been shown to have good correlation with digital subtraction angiography (DSA) but has been criticised for its variability. One source of this is the variation in results between studies responsible for re‐validating velocity criteria to match the established treatment thresholds of internal carotid artery (ICA) stenosis. The aim of this study was to develop velocity criteria and determine the presence of inter‐sonographer variation of CDUS when grading ICA stenosis in our department. Five sonographers measured the degree of ICA stenosis with CDUS in 33 patients who also underwent DSA. Receiver operator characteristic curve analysis was used to develop optimal velocity criteria for the 50%, 70% and 90% ICA stenosis thresholds as a group and for each individual sonographer. A peak systolic velocity ratio of ≥ 3.25 was shown to have the highest accuracy (91.5%) for predicting a 70% stenosis. A moderate value of κ (0.53 ± 0.027) was calculated if the optimum velocity criterion was employed for each sonographer. There was no significant variation between the ability of sonographers to grade ICA stenosis (P > 0.05) and an excellent ICC of 0.911 was calculated. This study provides evidence to suggest that CDUS in our department is not an operator‐dependant test for the investigation of ICA stenosis.     

MRA应用于颈动脉外科之经验

了解ＮＭＲ在颈动脉外科的应用价值。方法：对本院头颈科１９９７年８月－１９９９年５月收治的涉及颈动脉疾病患者９例中６例,进行了术前ＭＲＡ检测,其中２例实施术后分析检测。结果颈动脉体瘤,颈动脉瘤及某些颈部转移肿瘤累及颈动脉的ＭＲＡ表现与血造影相似;ＭＲＡ可直接显示预动脉分歧部切除术后脑血管侧支循环血管影像。     

颈动脉分歧部切除术后脑血流代偿机制的血流动力学及影像学研究

天津市肿瘤医院自１９７９年首次成功地完成了第１例计划性不进行血管重建的肿瘤合并颈动脉分歧部切除术以来，到１９９３年共行此术２０例。术后，除因其它原因死亡４例外，１６例健在，始终未出现脑血管合并症。为了解颈动脉分歧部切除术后脑血流代偿供血机制，对术后健在的９例（第１组）及术前颈动脉压迫锻炼合格的６例（第２组）患者进行了彩色多普勒血流显像、经颅多普勒、氙脑图成像仪、颈脑血管数字减影造影、单光子计算机断层扫描及微机脑血流图等现代有关脑血流动力学及影像学的检测研究。多项检测研究结果显示：１）两组患者脑代偿供血均良好，表明切除一侧颈动脉后仍能充分代偿脑正常供血；２）脑血流代偿供血的主要方式是通过增加血流速度、增粗血管内径及开放脑底动脉环的交通支来完成；３）术前颈动脉压迫锻炼确实能起到促进脑侧支循环充分建立的作用，压迫锻炼须与脑血流图监测相结合，用以预测脑代偿供血状况     

Direct B‐mode NASCET‐style stenosis measurement and Doppler ultrasound as parameters for assessment of internal carotid artery stenosis

Doppler ultrasound grading of internal carotid artery (ICA) stenosis using the two parameters of spectral analysis and internal carotid to common carotid artery peak systolic velocity (ICA/CCA PSV) ratio is well established. The improvements in B‐Mode ultrasound image quality now make direct ultrasound NASCET‐style stenosis measurement possible. We demonstrate that longitudinal B‐mode imaging can produce accurate North American Symptomatic Carotid Endarterectomy Trial (NASCET) style measurements which have good correlation with angiographic images. Ultrasound B‐mode stenosis measurement provides a third parameter which can be used in conjunction with the two Doppler parameters for the assessment of ICA stenosis. Taking the highest grade of stenosis of the three parameters produces a sensitivity of 100% for the detection of greater than 50% and greater than 80% stenosis with specificity of 66 and 90%, respectively. The performance of satisfactory B‐mode imaging against digital subtraction angiography (DSA) was very encouraging. When the B‐mode stenosis measurement showed a normal ICA, the positive predictive value (PPV) of the DSA being normal was 94%. When the B‐mode stenosis measurement was 35% or less, the PPV of the DSA stenosis being 35% or less was 93%. These excellent results support the use of good quality B‐Mode NASCET style stenosis measurement as the initial ultrasound measurement, with Doppler ultrasound only being performed when the B‐mode stenosis measurement is greater than 35% or if the B‐mode image is unsatisfactory. This approach would save considerable time enabling better utilization of ultrasound resources.     

The Carotid Bruit: Is it a Useful Sign of Vessel Disease? A Clinical and Digital Angiographic Study

203 consecutive patients for Digital subtraction angiography of the cranio-cervical vessels were also assessed for audible bruits in the neck. The sensitivity of bruit as an indicator of carotid disease is 0.57, with specificity of 0.83. The presence of a bruit is a strong indication for angiography by the simple and safe method of DSA.     

Cerebral hyperperfusion syndrome post‐carotid artery stenting

Cerebral hyperperfusion syndrome is increasingly recognized as a complication in carotid artery stenting for severe internal carotid artery stenosis. This study reviews the cases of hyperperfusion syndrome occurring after this procedure. We reviewed our database of 170 cases of internal carotid artery stenting carried out at our hospital between January 1999 and June 2006. A radiology search was also carried out to identify those who had CT or MRI within 1 month of post‐carotid artery stenting. We had four patients who developed cerebral hyperperfusion syndrome. One patient developed cerebral oedema, one patient had petechial intracerebral haemorrhage and two patients had large intracerebral haemorrhages, one of whom died. This gives a risk of 2.3% (95% confidence interval 2.27–2.323). All patients with cerebral haemorrhage presented within 6 h. Both patients with large intracerebral haemorrhage had carotid stenting within 3 weeks after presentation of symptoms and all had critically severe stenosis of 95% or more. In our series, large intracerebral haemorrhage has occurred only in patients who have been treated early. Cerebral hyperperfusion is an uncommon but serious complication post‐carotid stenting. Further studies comparing early treatment of endarterectomy and carotid stenting are awaited.     

局部晚期鼻咽癌调强放疗后颈动脉损伤的临床分析

[目的]探讨局部晚期鼻咽癌调强放疗与颈动脉损伤的关系。[方法]系统随访91例Ⅲ-Ⅳa期鼻咽癌初治患者。全组患者均采用调强放疗技术（原发灶总剂量70-72Gy/32f,42-44d;颈淋巴结转移灶65-68Gy/32f,42-44d;高危预防区域60Gy/32f,42-44d;低危预防区域50Gy/28f,35-38d）放疗结束后定期通过磁共振颈血管成像（MRA）和/或颈部血管彩色多普勒随访患者颈动脉损伤发生情况。[结果]至随访截止日,91例患者中共有20例在MRA和/或颈部血管彩色多普勒上表现出颈动脉损伤,发生率为22.0%,1年、2年、3年、4年的发生率分别为11.0%（10/91）、16.5%（15/91）、20.9%（19/91）、22.0%（20/91）,其中有10例患者同时进行了MRA及颈部血管彩色多普勒检查,6例患者颈部血管彩色多普勒的阳性结果出现在MRA之前,3例患者仅颈部血管彩色多普勒有阳性结果,1例两者同时发现颈部血管损伤。发生损伤的主要部位为颈总动脉（12例）、椎动脉（11例）及颈内动脉（6例）。[结论]局部晚期鼻咽癌患者调强放疗后颈动脉损伤的发生率高,联合多种影像学检查定期复查可以及早发现放疗后颈动脉损伤。