Barr R M, Dillon W P, Wilson C B
Department of Radiology, University of California San Francisco, USA.
AJNR Am J Neuroradiol. 1996 Jan;17(1):71-8.
To report clinical and MR features that suggest telangiectatic vascular malformations of the pons:
The MR scans and clinical data of 12 patients demonstrating an enhancing pontine lesion with minimal or no signal abnormality on T2-weighted images were reviewed. None of the patients underwent angiography or biopsy. Follow-up scans, available for all patients between 3 weeks and 40 months (range, 11.5 months), were reviewed.
The patients presented with a variety of symptoms including headache (n = 4), vertigo (n = 3), gait abnormality (n = 3), and hearing loss (n = 2). Two were referred for biopsy or treatment of presumed pontine glioma. On precontrast MR, 3 of 12 lesions were isointense on both T1- and T2-weighted images. Three of 12 lesions were slightly hypointense on T1-weighted images and 8 of 12 were slightly hyperintense on T2-weighted images. Postgadolinium images showed a discrete focus of enhancement with irregular or brushlike borders. Eight of 12 had an anomalous draining vessel from the lesion to the surface of the pons. None demonstrated mass effect or hemorrhage. Gradient-echo sequences in 7 patients all showed marked T2 shortening, despite the absence of hemorrhage on either T1- or T2-weighted images. None of the follow-up scans showed radiographic or clinical progression.
The benign clinical course, lack of mass effect, and minimal or no T2 prolongation argue against neoplasm and instead indicate a vascular cause. We suspect the decreased signal on gradient-echo sequences represents elevated intravascular deoxyhemoglobin from stagnant blood flow. The findings are atypical for cavernous angioma or classic venous malformation. Although pathologic confirmation is lacking, the radiographic features are most consistent with capillary telangiectasia or a transitional capillary-venous malformation. Despite the absence of progression or hemorrhage in any of the patients to date, the long-term prognosis currently is unknown. We emphasize the importance of recognizing the nonneoplastic nature of these lesions.
报告提示脑桥毛细血管扩张性血管畸形的临床及磁共振成像（MR）特征。
回顾12例患者的MR扫描及临床资料，这些患者在T2加权图像上表现为脑桥病变强化，且信号异常轻微或无信号异常。所有患者均未接受血管造影或活检。对所有患者在3周~40个月（范围11.5个月）期间的随访扫描进行了回顾。
患者表现出多种症状，包括头痛（4例）、眩晕（3例）、步态异常（3例）及听力丧失（2例）。2例因疑似脑桥胶质瘤而接受活检或治疗。在增强前MR成像上，12个病变中有3个在T1加权和T2加权图像上均呈等信号。12个病变中有3个在T1加权图像上略呈低信号，12个中有8个在T2加权图像上略呈高信号。钆剂增强后图像显示强化灶离散，边界不规则或呈毛刷状。12个病变中有8个有异常引流血管从病变延伸至脑桥表面。均未显示占位效应或出血。7例患者的梯度回波序列均显示明显的T2缩短，尽管T1加权或T2加权图像上均无出血表现。随访扫描均未显示影像学或临床进展。
良性的临床病程、无占位效应以及T2延长轻微或无T2延长，提示病变并非肿瘤，而是血管源性。我们怀疑梯度回波序列上信号降低代表因血流停滞导致血管内脱氧血红蛋白升高。这些表现对于海绵状血管瘤或典型静脉畸形来说并不典型。尽管缺乏病理证实，但影像学特征最符合毛细血管扩张或过渡型毛细血管-静脉畸形。尽管目前尚无患者出现进展或出血，但长期预后仍未知。我们强调认识这些病变非肿瘤性质的重要性。
