Susceptibility-weighted MR imaging for diagnosis of capillary telangiectasia of the brain

Typical and Emerging Diagnostic MRI Features in Multiple Sclerosis

Magnetic resonance imaging (MRI) stands as the most sensitive paraclinical technique for detecting the demyelinating lesions characteristic of multiple sclerosis (MS). Consequently, MRI plays a pivotal role in establishing an accurate and timely diagnosis of the disease, ultimately based on the application of the McDonald criteria. Early diagnosis is particularly important as it facilitates the prompt initiation of disease-modifying treatments, deemed most effective during the initial phases of MS. This review article examines the recommended standardized MRI protocol, as well as the classic imaging features of MS in the brain, optic nerve, and spinal cord, capable of discriminating, in most cases, MS from other disorders that can mimic this disease. Additionally, novel MR imaging findings, such as the central vein sign and paramagnetic rim lesion, which have been proposed as new imaging biomarkers to enhance diagnostic specificity for MS, are also discussed. These emerging features are likely to be incorporated in the future iterations of the McDonald criteria, and therefore, radiologists should be familiar with their appearance and with the optimal MRI protocols required for their detection.

Coexistence of brain capillary telangiectasia and venous angioma: A case report and literature review

While Cerebral vascular malformations exhibit distinct clinical and radiographical features, rare instances of coexisting lesions occur. This case report sheds light on the rare coexistence of brain capillary telangiectasia and venous angioma in a patient presenting with a seizure attributed to frontal lobe bleeding. Though often silent, brain capillary telangiectasia can manifest with serious life-threatening intracranial bleeding. Therefore, in cases of spontaneous intracranial bleeding, an MRI of the head is crucial to rule out such cerebral vascular malformations.

[Capillary telangiectasia]

Brain capillary telangiectasia is usually a small collection of dilated capillary-like vessels. In most cases it is a harmless incidental finding with no clinical significance. They are most commonly located in the pons. In terms of image morphology, they show brush-like signal extinction in T2*/SWI (susceptibility-weighted imaging) sequences and contrast enhancement in T1-weighted images. Other sequences are usually unremarkable unless they involve unusually large capillary telangiectasias. Angiographically they usually remain silent. Sometimes they are associated with venous abnormalities and/or cavernomas. Their distinctive radiographic features usually allow for a reliable diagnosis. Differential diagnostic considerations, such as differentiation from a tumorous or inflammatory process, are sometimes necessary.

Nonlesional Sources of Contrast Enhancement on Postgadolinium "Black-Blood" 3D T1-SPACE Images in Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

We hypothesized that 3D T1-TSE "black-blood" images may carry an increased risk of contrast-enhancing lesion misdiagnosis in patients with MS because of the misinterpretation of intraparenchymal vein enhancement. Thus, the occurrence of true-positive and false-positive findings was compared between standard MPRAGE and volumetric interpolated brain examination techniques.

MATERIALS AND METHODS

Sampling perfection with application-optimized contrasts by using different flip-angle evolution (SPACE) images obtained from 232 patients with MS, clinically isolated syndrome, or radiologically isolated syndrome were compared with standard MPRAGE and volumetric interpolated brain examination images. The intraparenchymal vein contrast-to-noise ratio was estimated at the level of the thalami. Contrast-enhancing lesions were blindly detected by 2 expert readers and 1 beginner reader. True- and false-positives were determined by senior readers' consensus. True-positive and false-positive frequency differences and patient-level diagnosis probability were tested with the McNemar test and OR. The contrast-to-noise ratio and morphology were compared using the Mann-Whitney U and χ² tests.

RESULTS

The intraparenchymal vein contrast-to-noise ratio was higher in SPACE than in MPRAGE and volumetric interpolated brain examination images (P < .001, both). There were 66 true-positives and 74 false-positives overall. SPACE detected more true-positive and false-positive results (P range < .001-.07) but did not increase the patient's true-positive likelihood (OR = 1 1.29, P = .478-1). However, the false-positive likelihood was increased (OR = 3.03-3.55, P = .008-.027). Venous-origin false-positives (n = 59) with contrast-to-noise ratio and morphology features similar to small-sized (≤14 mm³ P = .544) true-positives occurred more frequently in SPACE images (P < .001).

CONCLUSIONS

Small intraparenchymal veins may confound the diagnosis of enhancing lesions on postgadolinium black-blood SPACE images.

The diagnostic value of postcontrast susceptibility-weighted imaging in the assessment of intracranial brain neoplasm at 3T

BACKGROUND

Susceptibility-weighted imaging (SWI) is occasionally performed with intravenous gadolinium (Gd). It was reported that SWI can be performed after Gd injection without information loss or signal change.

PURPOSE

To investigate the diagnostic value of contrast-enhanced SWI (CE-SWI) in the assessment of intracranial brain neoplasm.

MATERIAL AND METHODS

After obtaining the approval of the local ethics committee, 35 brain neoplasm patients (24 with metastasis and 11 with glioblastoma multiforme [GBM]) were enrolled. In order to investigate the value of using CE-SWI, two neuroradiologists performed an evaluation of the frequency of the intratumoral susceptibility signals (ITSS) in SWI and CE-SWI with visual assessment using 5-grade scales. We evaluated the visibility of the tumor margins and the internal architecture of tumors on T1-weighted imaging (T1WI), contrast-enhanced T1 (CE-T1), SWI, and CE-SWI.

RESULTS

The contrast-enhanced scans (CE-T1 and CE-SWI) showed statistically significant higher scores compared to non-enhanced scans (T1WI and SWI) for the analysis of the tumor margin in GBM and metastasis (P < 0.05, Wilcoxon signed rank test). Statistically significant higher scores are noted in GBMs compared to metastases in the visibility of the internal architecture of tumors on CE-SWI and the visibility of the tumor margin on CE-T1 (P < 0.05, Mann-Whitney test).

CONCLUSION

Based on our results, SWI can be performed after gadolinium injection without information loss or signal change. CE-SWI is useful in evaluating intracranial neoplasm due to its ability to simultaneously demonstrate both ITSS that are not visible with conventional magnetic resonance sequences and contrast enhancement.

Susceptibility-weighted Imaging: Technical Essentials and Clinical Neurologic Applications

Susceptibility-weighted imaging (SWI) evolved from simple two-dimensional T2*-weighted sequences to three-dimensional sequences with improved spatial resolution and enhanced susceptibility contrast. SWI is an MRI sequence sensitive to compounds that distort the local magnetic field (eg, calcium and iron), in which the phase information can differentiate. But the term SWI is colloquially used to denote high-spatial-resolution susceptibility-enhanced sequences across different MRI vendors and sequences even when phase information is not used. The imaging appearance of SWI and related sequences strongly depends on the acquisition technique. Initially, SWI and related sequences were mostly used to improve the depiction of findings already known from standard two-dimensional T2*-weighted neuroimaging: more microbleeds in patients who are aging or with dementia or mild brain trauma; increased conspicuity of superficial siderosis in Alzheimer disease and amyloid angiopathy; and iron deposition in neurodegenerative diseases or abnormal vascular structures, such as capillary telangiectasia. But SWI also helps to identify findings not visible on standard T2*-weighted images: the nigrosome 1 in Parkinson disease and dementia with Lewy bodies, the central vein and peripheral rim signs in multiple sclerosis, the peripheral rim sign in abscesses, arterial signal loss related to thrombus, asymmetrically prominent cortical veins in stroke, and intratumoral susceptibility signals in brain neoplasms.

Susceptibility-Weighted Imaging as a Distinctive Imaging Technique for Providing Complementary Information for Precise Diagnosis of Neurologic Disorder

Various sequences have been developed for MRI to aid in the radiologic diagnosis. Among the various MR sequences, susceptibility-weighted imaging (SWI) is a high-spatial-resolution, three-dimensional gradient-echo MR sequence, which is very sensitive in detecting deoxyhemoglobin, ferritin, hemosiderin, and bone minerals through local magnetic field distortion. In this regard, SWI has been used for the diagnosis and treatment of various neurologic disorders, and the improved image quality has enabled to acquire more useful information for radiologists. Here, we explain the principle of various signals on SWI arising in neurological disorders and provide a retrospective review of many cases of clinically or pathologically proven disease or components with distinctive imaging features of various neurological diseases. Additionally, we outline a short and condensed overview of principles of SWI in relation to neurological disorders and describe various cases with characteristic imaging features on SWI. There are many different types diseases involving the brain parenchyma, and they have distinct SWI features. SWI is an effective imaging tool that provides complementary information for the diagnosis of various diseases.

Simultaneous feedback control for joint field and motion correction in brain MRI

T2*-weighted gradient-echo sequences count among the most widely used techniques in neuroimaging and offer rich magnitude and phase contrast. The susceptibility effects underlying this contrast scale with B₀, making T2*-weighted imaging particularly interesting at high field. High field also benefits baseline sensitivity and thus facilitates high-resolution studies. However, enhanced susceptibility effects and high target resolution come with inherent challenges. Relying on long echo times, T2*-weighted imaging not only benefits from enhanced local susceptibility effects but also suffers from increased field fluctuations due to moving body parts and breathing. High resolution, in turn, renders neuroimaging particularly vulnerable to motion of the head. This work reports the implementation and characterization of a system that aims to jointly address these issues. It is based on the simultaneous operation of two control loops, one for field stabilization and one for motion correction. The key challenge with this approach is that the two loops both operate on the magnetic field in the imaging volume and are thus prone to mutual interference and potential instability. This issue is addressed at the levels of sensing, timing, and control parameters. Performance assessment shows the resulting system to be stable and exhibit adequate loop decoupling, precision, and bandwidth. Simultaneous field and motion control is then demonstrated in examples of T2*-weighted in vivo imaging at 7T.

Appearance of an unusual ring enhancing brain capillary telangiectasia on 3.0T MRI with dynamic susceptibility contrast perfusion

We present the appearance of brain capillary telangiectasia on 3.0T magnetic resonance imaging (MRI) perfusion. A 42-year-old female presented with intermittent left arm weakness and paresthesia. Initial 1.5T MRI obtained 2 months after presentation demonstrated a 6 mm right caudate head lesion with ring-like enhancement, and no significant surrounding edema or mass effect. On gradient echo there was mild associated susceptibility artifact. Follow-up 3.0T MRI demonstrated increased blooming on 3.0T imaging relative to prior 1.5T imaging. The lesion also demonstrated increased blood volume on dynamic susceptibility contrast perfusion. Given these imaging findings and interval stability, a definitive imaging diagnosis of capillary telangiectasia was made. Recognition of the MRI findings of capillary telangiectasia is imperative to avoid misdiagnosis and prevent unnecessary intervention.

Assessment of lesions on magnetic resonance imaging in multiple sclerosis: practical guidelines

MRI has improved the diagnostic work-up of multiple sclerosis, but inappropriate image interpretation and application of MRI diagnostic criteria contribute to misdiagnosis. Some diseases, now recognized as conditions distinct from multiple sclerosis, may satisfy the MRI criteria for multiple sclerosis (e.g. neuromyelitis optica spectrum disorders, Susac syndrome), thus making the diagnosis of multiple sclerosis more challenging, especially if biomarker testing (such as serum anti-AQP4 antibodies) is not informative. Improvements in MRI technology contribute and promise to better define the typical features of multiple sclerosis lesions (e.g. juxtacortical and periventricular location, cortical involvement). Greater understanding of some key aspects of multiple sclerosis pathobiology has allowed the identification of characteristics more specific to multiple sclerosis (e.g. central vein sign, subpial demyelination and lesional rims), which are not included in the current multiple sclerosis diagnostic criteria. In this review, we provide the clinicians and researchers with a practical guide to enhance the proper recognition of multiple sclerosis lesions, including a thorough definition and illustration of typical MRI features, as well as a discussion of red flags suggestive of alternative diagnoses. We also discuss the possible place of emerging qualitative features of lesions which may become important in the near future.

Brain capillary telangiectasias: from normal variants to disease

BACKGROUND

Brain capillary telangiectasias (BCTs) are small, dilated capillary networks in the brain that are most commonly asymptomatic. Though rare, symptomatic cases of BCTs have been reported, and it is therefore important to understand the nature of these lesions in order to facilitate proper recognition. Relative to other intracranial vascular malformations, updated information on the various epidemiologic, radiographic, and pathologic features of BCTs within the published literature may be inadequate.

METHODS

We searched the PubMed database for prior reports of symptomatically-manifested BCTs. Moreover, Google Scholar and PubMed were searched in order to review current epidemiologic, radiographic, pathologic, and pathogenetic features of BCTs.

RESULTS

Forty-eight published studies were included for a total of 99 individual cases of BCTs with symptomatic manifestations. Thirty-three symptomatic BCTs were hemorrhagic in nature, while 66 were non-hemorrhagic. The mean age at presentation of hemorrhagic lesions was 25.5 years, and the most common location was the supratentorial CNS (54.5%) with motor disturbance representing the most commonly encountered presenting symptom (26.1%). 15.2% of hemorrhagic lesions were treated with surgical removal. In non-hemorrhagic lesions, the mean age at presentation was 39.8 years with the pons being the most common lesion location (78.5%) and headache being the most common presenting symptom (22.2%). 12.1% of patients with non-hemorrhagic lesions were treated with surgical removal.

CONCLUSIONS

Despite their rarity, symptomatic BCTs, both hemorrhagic and non-hemorrhagic, can cause devastating neurological sequelae, potentially through multiple mechanisms. The large majority of these lesions do not require intervention, though surgical removal has been achieved with good outcome in select cases. Further documentation of symptomatic manifestations with or without surgical intervention is vital in order to further understand the clinical, surgical, and pathogenic implications of these less-appreciated vascular malformations.

Brain tumour post-treatment imaging and treatment-related complications

Purpose

The imaging of primary and metastatic brain tumours is very complex and relies heavily on advanced magnetic resonance imaging (MRI). Utilisation of these advanced imaging techniques is essential in helping clinicians determine tumour response after initiation of treatment. Many options are currently available to treat brain tumours, and each can significantly alter the brain tumour appearance on post-treatment imaging. In addition, there are several common and uncommon treatment-related complications that are important to identify on standard post-treatment imaging.

Methods

This article provides a review of the various post-treatment-related imaging appearances of brain neoplasms, including a discussion of advanced MR imaging techniques available and treatment response criteria most commonly used in clinical practice. This article also provides a review of the multitude of treatment-related complications that can be identified on routine post-treatment imaging, with an emphasis on radiation-induced, chemotherapy-induced, and post-surgical entities.

Summary/Conclusion

Although radiological evaluation of brain tumours after treatment can be quite challenging, knowledge of the various imaging techniques available can help the radiologist distinguish treatment response from tumour progression and has the potential to save patients from inappropriate alterations in treatment. In addition, knowledge of common post-treatment-related complications that can be identified on imaging can help the radiologist play a key role in preventing significant patient morbidity/mortality.

Teaching points

• Contrast enhancement does not reliably define tumour extent in many low-grade or infiltrative gliomas.

• Focal regions of elevated cerebral blood volume (rCBV) on dynamic susceptibility contrast (DSC) perfusion-weighted imaging are suggestive of tumour growth/recurrence.

• Brain tumour treatment response criteria rely on both imaging and clinical parameters.

• Chemotherapeutic agents can potentiate many forms of radiation-induced injury.

• Ipilimumab-induced hypophysitis results in transient diffuse enlargement of the pituitary gland.

[Vascular pathologies and vascular anatomical variants of the posterior cranial fossa]

CLINICAL/METHODICAL ISSUE

The posterior fossa is the location of some specific vascular pathologies and vascular anatomical variants that are important for radiologists to know and recognize. Vascular malformations that are also found in the supratentorial region have some divergent characteristics in the posterior fossa.

PRACTICAL RECOMMENDATIONS

Knowledge of the vascular anatomy of the posterior fossa and its variants is important for an understanding of vascular pathologies.

Management of Unruptured Intracranial Aneurysms and Cerebrovascular Malformations

PURPOSE OF REVIEW

Unruptured intracranial aneurysms and vascular malformations are detected more frequently because of the increased use and availability of brain imaging. Management of these entities requires knowledge of which patients are at high risk for hemorrhage and what treatment options are available. This article summarizes the epidemiology, natural history, and management strategies for unruptured intracranial aneurysms, arteriovenous malformations, cavernous malformations, developmental venous anomalies, and capillary telangiectasias.

RECENT FINDINGS

Pooled cohort studies and meta-analyses have improved the ability to predict hemorrhage for each vascular abnormality. Scores and tools have been developed to aid the practitioner in predicting hemorrhage risk for unruptured intracranial aneurysms. Advances in endovascular techniques for unruptured intracranial aneurysms have improved the ability to treat difficult wide-necked aneurysms.

SUMMARY

Unruptured intracranial aneurysms are a common incidental finding. The PHASES (population, hypertension, age, size of aneurysm, earlier subarachnoid hemorrhage from another aneurysm, site of aneurysm) score and Unruptured Intracranial Aneurysm Treatment Score may be useful tools for predicting natural history and treatment recommendations. The overall risk of hemorrhage for both arteriovenous malformations and cavernous malformations is about 2% to 4% per year. With both of these entities, prior hemorrhage predicts future hemorrhage. In addition, other select patient and radiologic factors influence risk of hemorrhage. The risk of future hemorrhage should be compared to the risk of treatment. Developmental venous anomalies and capillary telangiectasias are largely benign entities and rarely symptomatic.

Susceptibility-weighted Imaging in Neurovascular Disease

Susceptibility-weighted imaging (SWI) has become an important imaging sequence in the evaluation of patients with neurovascular disease. In this review, we provide a general overview of the physics of SWI and describe how image contrast is produced with this technique. We provide a general approach and differential diagnosis for 2 commonly encountered radiographic patterns seen with SWI in neurovascular disease. Finally, we discuss specific neurovascular applications of SWI, including its application in acute stroke, vascular malformations, venous thrombosis, and evaluation of cerebral microbleeds.

Symptomatic capillary telangiectasia of the pons: three pediatric cases diagnosed by suspectibility-weighted imaging

INTRODUCTION

Brain capillary telangiectasias (BCT) are small, clinically benign, usually asymptomatic and rarely seen lesions during childhood. Large symptomatic BCT during childhood are extremely rare, with only a few reports in the literature. They usually cannot be detected easily on conventional magnetic resonance imaging and angiography.

METHODS

We present the first pediatric case series of large pontine BCT presenting with distinct symptoms and in whom the lesions were detected by susceptibility-weighted imaging (SWI), for the first time to date. SWI provides a crucial imaging modality for BCT.

RESULTS

We suggest that the combination of signal intensity loss on SWI and focal enhancement in a lesion otherwise not seen on conventional MR images is diagnostic for BCT and serves to discard serious differential diagnoses with high specificity, reassuring patients and referring physicians.

CONCLUSION

We would like to emphasize clinical and radiological findings of BCT and utility of SWI images on MRI for the confirmation of diagnosis in the pediatric age group.

Symptomatic large or giant capillary telangiectasias: management and outcome in 5 cases

Brain capillary telangiectasias (BCTs) are usually small and benign with a predilection in the pons and basal ganglion. Reports of large and symptomatic BCTs are rare. Large BCTs have a much higher risk of causing uncontrolled bleeding and severe neurological defects, and they can be fatal if left untreated. Therefore, large BCTs should be managed with special caution. Because of the lack of reports, diagnosis of large BCTs has been difficult. Strategies of management are undefined for large or giant BCTs.

The current study presents 5 cases of giant and large BCTs. To the authors’ knowledge, this is the largest series of this disease ever reported. Radiological findings, histopathological characteristics, clinical presentations, and surgical management were analyzed in 5 symptomatic, unusually large BCTs (mean diameter 5.06 cm, range 1.8–8 cm).

Four patients presented with focal or generalized seizures, and 1 patient presented with transient vision loss attributed to the lesions. Gross-total resection of the lesion was achieved in all patients. After surgery, the 4 patients with seizures were symptom free for follow-up periods varying from more than 1 to 5 years with no additional neurological deficits.

The unique location, radiological characteristics, and clinical course suggest that giant BCTs could be a different entity from small BCTs. Surgery might be a good option for treatment of patients with intractable neurological symptoms, especially in those with surgically accessible locations. Complete removal would be anticipated to provide relief of the symptoms without causing new neurological deficits.

Magnetic resonance susceptibility weighted imaging in neurosurgery: current applications and future perspectives

Susceptibility weighted imaging (SWI) is a relatively new imaging technique. Its high sensitivity to hemorrhagic components and ability to depict microvasculature by means of susceptibility effects within the veins allow for the accurate detection, grading, and monitoring of brain tumors. This imaging modality can also detect changes in blood flow to monitor stroke recovery and reveal specific subtypes of vascular malformations. In addition, small punctate lesions can be demonstrated with SWI, suggesting diffuse axonal injury, and the location of these lesions can help predict neurological outcome in patients. This imaging technique is also beneficial for applications in functional neurosurgery given its ability to clearly depict and differentiate deep midbrain nuclei and close submillimeter veins, both of which are necessary for presurgical planning of deep brain stimulation. By exploiting the magnetic susceptibilities of substances within the body, such as deoxyhemoglobin, calcium, and iron, SWI can clearly visualize the vasculature and hemorrhagic components even without the use of contrast agents. The high sensitivity of SWI relative to other imaging techniques in showing tumor vasculature and microhemorrhages suggests that it is an effective imaging modality that provides additional information not shown using conventional MRI. Despite SWI's clinical advantages, its implementation in MRI protocols is still far from consistent in clinical usage. To develop a deeper appreciation for SWI, the authors here review the clinical applications in 4 major fields of neurosurgery: neurooncology, vascular neurosurgery, neurotraumatology, and functional neurosurgery. Finally, they address the limitations of and future perspectives on SWI in neurosurgery.

A Rare Association of Trigeminal Autonomic Cephalgia: Pontine Capillary Telangiectasia

This report describes a case of pontine capillary telangiectasia in a 43-year-old woman with a clinical diagnosis of trigeminal autonomic cephalgia. The possible association with pontine capillary telangiectasia and trigeminal autonomic cephalgia is discussed.

Incidental findings on brain and spine imaging in children

In recent years, the utilization of diagnostic imaging of the brain and spine in children has increased dramatically, leading to a corresponding increase in the detection of incidental findings of the central nervous system. Patients with unexpected findings on imaging are often referred for subspecialty evaluation. Even with rational use of diagnostic imaging and subspecialty consultation, the diagnostic process will always generate unexpected findings that must be explained and managed. Familiarity with the most common findings that are discovered incidentally on diagnostic imaging of the brain and spine will assist the pediatrician in providing counseling to families and in making recommendations in conjunction with a neurosurgeon, when needed, regarding additional treatments and prognosis.

Preoperative evaluation of collateral venous anastomoses in meningioma involving cerebral venous sinus by susceptibility weighted imaging

Precise preoperative identification of the collateral venous anastomoses is critical for proper surgical management of patients with meningioma involving sinus. This study was to assess the feasibility of susceptibility weighted imaging (SWI) to delineate the collateral venous anastomoses before surgery. Twenty-five patients with meningiomas that were involved in sinuses underwent surgery and the collateral anastomoses were evaluated with SWI and phase-contrast magnetic resonance venography (MRV) before surgery. The results obtained with SWI were compared with those obtained with MRV. Intraoperative findings were used as the gold standard. By surgery, a total of 98 collateral anastomotic veins were identified in the 25 patients. SWI depicted 85 collateral anastomotic veins close to the meningioma with a sensitivity of 87%, whereas MRV showed 57 collateral anastomotic veins with a sensitivity of 58%. The detectability of collateral anastomotic veins in SWI images was superior to MRV. The results suggest that SWI is superior to MRV and could provide more reliable information on the collateral venous anastomoses in patients with meningioma.

Cerebral tumor or pseudotumor?

Pseudotumoral lesions are uncommon but important to identity lesions. They can occur during inflammatory diseases (systemic diseases, vasculitis, demyelinating diseases), infectious, and vascular diseases. Also, in a patient with a treated tumor, pseudo-progression and radionecrosis must be differentiated from the tumoral development. Diagnosis can be difficult on an MRI scan, but some MRI aspects in conventional sequences, diffusion, perfusion and spectroscopy can suggest the pseudotumoral origin of a lesion. Imaging must be interpreted according to the context, the clinic and the biology. The presence of associated intracranial lesions can orientate towards a systemic or infectious disease. A T2 hyposignal lesion suggests granulomatosis or histiocytosis, especially if a meningeal or hypothalamic-pituitary involvement is associated. Non-tumoral lesions are generally not hyperperfused. In the absence of a definitive diagnosis, the evolution of these lesions, whether under treatment or spontaneous, is fundamental.

Susceptibility-weighted MR imaging: a better technique in the detection of capillary telangiectasia compared with T2* gradient-echo

BACKGROUND AND PURPOSE

Enhancing lesions on brain MR imaging can present a diagnostic quandary as both benign lesions such as brain capillary telangiectasia and pathologic lesions such as demyelination may appear similar. Stagnation of blood in low-flow venous channels of brain capillary telangiectasias results in susceptibility effect secondary to the increased local deoxyhemoglobin. Both T2* gradient-echo imaging and SWI were demonstrated as valuable in the diagnosis of brain capillary telangiectasia. Because SWI is more sensitive to susceptibility changes than gradient-echo, we aim to demonstrate increased diagnostic value of SWI compared with gradient-echo in making the diagnosis of brain capillary telangiectasia.

MATERIALS AND METHODS

We retrospectively reviewed the MR images of 17 patients with a presumed diagnosis of brain capillary telangiectasia and who were examined from June 2010 to September 2012. All patients underwent MR imaging at 1.5T with T1, T2, FLAIR, gradient-echo, SWI, and gadolinium-enhanced T1 sequences. Lesions were evaluated for the presence or absence of signal abnormality on each particular sequence.

RESULTS

All 17 brain capillary telangiectasias demonstrated distinct signal-intensity loss on SWI compared with 7 of 17 (41%) who showed signal-intensity loss on gradient-echo. The increased frequency of detection using SWI versus gradient-echo is statistically significant (z = 2.85, P < .01; χ(2) = 8.10, P < .01). Six of the lesions showed signal-intensity changes on T1 and/or T2 whereas the remaining lesions were isointense to normal brain.

CONCLUSIONS

Brain capillary telangiectasias are more conspicuous on SWI than gradient-echo imaging and other precontrast MR imaging. SWI is a valuable tool in diagnosing these benign lesions and should serve to increase diagnostic confidence.

Leptomeningeal collateralization in acute ischemic stroke: impact on prominent cortical veins in susceptibility-weighted imaging

BACKGROUND

The extent of hypoperfusion is an important prognostic factor in acute ischemic stroke. Previous studies have postulated that the extent of prominent cortical veins (PCV) on susceptibility-weighted imaging (SWI) reflects the extent of hypoperfusion. Our aim was to investigate, whether there is an association between PCV and the grade of leptomeningeal arterial collateralization in acute ischemic stroke. In addition, we analyzed the correlation between SWI and perfusion-MRI findings.

METHODS

33 patients with acute ischemic stroke due to a thromboembolic M1-segment occlusion underwent MRI followed by digital subtraction angiography (DSA) and were subdivided into two groups with very good to good and moderate to no leptomeningeal collaterals according to the DSA. The extent of PCV on SWI, diffusion restriction (DR) on diffusion-weighted imaging (DWI) and prolonged mean transit time (MTT) on perfusion-imaging were graded according to the Alberta Stroke Program Early CT Score (ASPECTS). The National Institutes of Health Stroke Scale (NIHSS) scores at admission and the time between symptom onset and MRI were documented.

RESULTS

20 patients showed very good to good and 13 patients poor to no collateralization. PCV-ASPECTS was significantly higher for cases with good leptomeningeal collaterals versus those with poor leptomeningeal collaterals (mean 4.1 versus 2.69; p=0.039). MTT-ASPECTS was significantly lower than PCV-ASPECTS in all 33 patients (mean 1.0 versus 3.5; p<0.00).

CONCLUSIONS

In our small study the grade of leptomeningeal collateralization correlates with the extent of PCV in SWI in acute ischemic stroke, due to the deoxyhemoglobin to oxyhemoglobin ratio. Consequently, extensive PCV correlate with poor leptomeningeal collateralization while less pronounced PCV correlate with good leptomeningeal collateralization. Further SWI is a very helpful tool in detecting tissue at risk but cannot replace PWI since MTT detects significantly more ill-perfused areas than SWI, especially in good collateralized subjects.

Large Capillary Telangiectasia and Developmental Venous Anomaly of the Basal Ganglia: An Unusual Finding

Brain capillary telangiectasias are small, benign, asymptomatic, angiographically occult lesions that are incidentally discovered either at autopsy or on MR imaging in most cases. They are commonly located in the pons and can be associated with other vascular malformations. We describe a case of an unusually large capillary telangiectasia associated with a developmental venous anomaly involving the basal ganglia in a young woman, in which MR serial imaging suggested the diagnosis and avoided an unnecessary stereotaxic biopsy.

Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study

OBJECTIVES

Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (SWAN) for the detection of HFVM.

METHODS

Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with SWAN and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). SWAN images were analysed by three blinded readers according to a three-point scale of the venous signal.

RESULTS

Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on SWAN images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). SWAN revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent.

CONCLUSIONS

SWAN appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, SWAN can routinely rule out HFVM in patients with atypical brain veins.

[Spinal vascular malformations]

Spinal vascular malformations are a group of rare diseases with different clinical presentations ranging from incidental asymptomatic findings to progressive tetraplegia. This article provides an overview about imaging features as well as clinical and therapeutic aspects of spinal arteriovenous malformations, cavernomas and capillary telangiectasia.