You are in: eMedicine Specialties > Radiology > BRAIN/SPINE Brain, Capillary TelangiectasiaArticle Last Updated: Jul 19, 2002AUTHOR AND EDITOR INFORMATIONSection 1 of 9
  Author: Andrew L Wagner, MD, Assistant Professor of Radiology, Instructional Faculty, University of Virginia School of Medicine; Director of Neuroradiology, Department of Radiology, Rockingham Memorial Hospital Andrew L Wagner is a member of the following medical societies: American College of Radiology, American Roentgen Ray Society, American Society of Neuroradiology, and Radiological Society of North America Editors: Robert A Koenigsberg, DO, MSc, FAOCR, Director of Neuroradiology, Professor, Department of Radiology, Drexel University College of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; James G Smirniotopoulos, MD, Professor of Radiology, Neurology, and Biomedical Informatics, Chairman, Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences Author and Editor Disclosure Synonyms and related keywords: capillary angioma, CTSs, abnormally dilated capillaries, brain vascular malformation, occult cerebrovascular malformations, OCVMs, cavernous angiomas, cavernomas, venous angiomas INTRODUCTIONSection 2 of 9
  BackgroundCapillary telangiectasias (CTSs) are small areas of abnormally dilated capillaries within otherwise normal brain tissue. Arteriovenous malformation, cavernous angioma, and venous angioma, CTS represent the 4 classifications of vascular malformations of the brain. Although CTSs most commonly occur in the pons, they have been described throughout the brain, and most are clinically insignificant. On rare occasions, CTSs are associated with hemorrhage, and they are occasionally found in conjunction with other vascular malformations. Most CTSs are found incidentally, and although the MRI appearance is fairly specific, distinguishing them from cavernous angiomas without hemorrhage is often impossible. These features have led to the adoption of the term occult cerebrovascular malformations (OCVMs) to describe the negative angiographic findings typically associated with these lesions. PathophysiologyCTSs are formed by a network of aneurysmally dilated capillaries that are usually located in a section of normal brain tissue, although adjacent areas of gliosis and small amounts of hemorrhage have been described. The presence of normal brain tissue between the capillaries is a pathologic characteristic that distinguishes CTSs from cavernous angiomas, although they may resemble each other on imaging studies. CTSs are typically small, ranging from a few millimeters to several centimeters in size. The pons is affected most often, but CTSs can occur anywhere in the brain or spine. McCormick et al described 30 CTSs in the posterior fossa, most of which involved the pons, and 22 in the supratentorial brain. Because they rarely hemorrhage, CTSs is almost always found incidentally, although 2 cases with large hemorrhages and 1 death due to local invasion are reported in the literature. CTSs are usually solitary, but they may also be found in association with other brain vascular malformations such as cavernous angiomas and venous angiomas. The association of CTSs with cavernomas is such that some have proposed that they represent two points on the spectrum of a single disease process. FrequencyUnited StatesCTSs are estimated to account for 16-20% of all brain vascular malformations. From autopsy studies, the prevalence is estimated to be 0.4%, although many of these CTSs are not visible on imaging studies. Mortality/Morbidity
RaceNo known race predilection exists. SexNo known sex predilection exists. AgeCTSs can occur in patients of any age. Clinical DetailsAlthough almost all patients with CTS are asymptomatic, CTSs have been associated with minor symptoms such as vertigo, headache, and dizziness, as well as weakness and seizures. No distinguishing clinical features are associated with CTS. Preferred ExaminationAlthough CTSs are occasionally visible on CT scans, the ideal means of detecting and imaging the lesions is contrast-enhanced MRI, which should include a gradient-echo sequence (eg, fast low-angle shot, gradient-recalled echo [GRE]). Angiography of any sort (ie, magnetic resonance angiography, computed tomographic angiography, conventional angiography) is not indicated because the lesions are typically occult on angiograms. Limitations of TechniquesAs sensitive as MRI has become, many lesions are not detectable and found only at autopsy. In addition, without the use of contrast material or fast low-angle shot imaging, most CTSs are not detectable. DIFFERENTIALSSection 3 of 9
[Brain, MRI Appearance Of Hemorrhage] [Multiple Sclerosis, Brain] Arachnoid Cyst Arachnoid Cyst Brain, Arteriovenous Malformation Brain, Cavernous Angiomas Brain, Lymphoma Multiple Sclerosis, Spine CT SCANSection 4 of 9
FindingsNonenhanced CT studies typically do not depict CTS, and most lesions are not visible even after the administration of contrast material. When visible, CTSs appear as a small area of subtle contrast enhancement. Rarely, a tiny calcification may be associated with the lesion. Degree of ConfidenceNegative CT findings do not exclude CTS because most lesions are occult. The appearance on contrast-enhanced CT scans is nonspecific. MRISection 5 of 9
FindingsMRI findings in CTS are variable, but contrast enhancement is required for diagnosis or even detection in almost all cases. Lee et al evaluated 18 patients and found enhancement in all patients, with little or no abnormal signal intensity on T2-weighted images; however, increased signal intensity may be seen occasionally. T1-weighted images may show isointensity. The enhancement pattern is described as lacelike (see Images 1, 3, 9) and usually subtle. Occasionally, an associated prominent draining vein is present (see Image 5). Recently, gradient-echo sequences have become useful in the detection and diagnosis of CTS (see Image 4). Both Barr et al and Lee et al describe susceptibility dephasing in all CTS lesions that are imaged by using GRE sequences. The exact reason why this susceptibility occurs is not clear, because hemosiderin and calcifications are not typically found on pathologic analysis. However, Lee and colleagues surmise that the hemoglobin within may be only partly converted to deoxyhemoglobin because the dilated capillaries result in relatively stagnant blood; therefore, it has only a mild paramagnetic effect. This theory explains the imaging differences between cavernous angiomas and CTSs. Because cavernous angiomas demonstrate susceptibility dephasing on GRE images because of the presence of hemosiderin, and sometimes calcifications, they also have markedly decreased signal intensity on T2-weighted images. Conversely, T2-weighted images of CTSs typically show no abnormality because the deoxyhemoglobin should not cause decreased signal intensity (see Images 2, 6-8). Degree of ConfidenceThe finding of a small area of enhancement without an abnormality or mass effect on a T2-weighted image and the finding of susceptibility dephasing on GRE images is strongly suggestive of a CTS, particularly if it the lesions is in the pons. If doubt exists, short-term follow-up studies can be performed to document stability of the lesion. Although capillary telangiectasia is usually not visible on T2-weighted and nonenhanced T1-weighted images, abnormalities on T2-weighted images can be associated with capillary telangiectasias. However, the presence of such signal intensity should prompt consideration of alternative diagnoses. ANGIOGRAPHYSection 6 of 9
FindingsAngiography of any sort (ie, magnetic resonance angiography, computed tomographic angiography, conventional angiography) is not indicated because CTSs are typically angiographically occult. However, tiny capillary vessels may be seen on the venous phase. INTERVENTIONSection 7 of 9
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REFERENCESSection 9 of 9
Brain, Capillary Telangiectasia excerpt Article Last Updated: Jul 19, 2002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
