Cerebral venous angiomas. MR imaging at 1.5 tesla

Developmental Venous Anomaly Presenting as an Acute Stroke Mimic

Several mimics of acute ischemic stroke may complicate the decision to administer intravenous thrombolysis. Developmental venous anomalies (DVA) are fairly common variants of normal cerebral vasculature and may occasionally present with acute focal neurologic symptoms. We report a case of DVA presenting with the acute onset of focal neurologic deficits and focal hypodensities on the CT of the brain, resulting in a dilemma regarding whether to administer intravenous tissue-type plasminogen activator (IV tPA) for stroke thrombolysis. Recognition of subtle brain changes on the CT that were inconsistent with an acute ischemic stroke led to further imaging and a definitive diagnosis. Developmental venous anomalies should be considered in the differential diagnosis of acute ischemic stroke.

Awad I, Dahlem K, Flemming K, Hart B, Kim H, Jusue-Torres I, Kondziolka D, Lee C, Morrison L, Rigamonti D, Rebeiz T, Tournier-Lasserve E, Waggoner D, Whitehead K. Synopsis of Guidelines for the Clinical Management of Cerebral Cavernous Malformations: Consensus Recommendations Based on Systematic Literature Review by the Angioma Alliance Scientific Advisory Board Clinical Experts Panel

BACKGROUND

Despite many publications about cerebral cavernous malformations (CCMs), controversy remains regarding diagnostic and management strategies.

OBJECTIVE

To develop guidelines for CCM management.

METHODS

The Angioma Alliance ( www.angioma.org ), the patient support group in the United States advocating on behalf of patients and research in CCM, convened a multidisciplinary writing group comprising expert CCM clinicians to help summarize the existing literature related to the clinical care of CCM, focusing on 5 topics: (1) epidemiology and natural history, (2) genetic testing and counseling, (3) diagnostic criteria and radiology standards, (4) neurosurgical considerations, and (5) neurological considerations. The group reviewed literature, rated evidence, developed recommendations, and established consensus, controversies, and knowledge gaps according to a prespecified protocol.

RESULTS

Of 1270 publications published between January 1, 1983 and September 31, 2014, we selected 98 based on methodological criteria, and identified 38 additional recent or relevant publications. Topic authors used these publications to summarize current knowledge and arrive at 23 consensus management recommendations, which we rated by class (size of effect) and level (estimate of certainty) according to the American Heart Association/American Stroke Association criteria. No recommendation was level A (because of the absence of randomized controlled trials), 11 (48%) were level B, and 12 (52%) were level C. Recommendations were class I in 8 (35%), class II in 10 (43%), and class III in 5 (22%).

CONCLUSION

Current evidence supports recommendations for the management of CCM, but their generally low levels and classes mandate further research to better inform clinical practice and update these recommendations. The complete recommendations document, including the criteria for selecting reference citations, a more detailed justification of the respective recommendations, and a summary of controversies and knowledge gaps, was similarly peer reviewed and is available on line www.angioma.org/CCMGuidelines .

Angiomi venosi o «anomalie di sviluppo venoso»

Sono stati studiati con RM 29 pazienti con anomalie di drenaggio venoso in condizio-ni basali e dopo Gadolinio-DTPA; 24 sono stati sottoposti anche ad angio-RM. Nella valutazione dei risultati è stato assegnato un punteggio: 0 quando l'anomalia non era evidenziata; 1 per la rappresentazione del solo collettore; 2 per la dimostrazione del collettore e delle vene midollari; 3 per la dimostrazione del collettore, delle vene midollari e del tipo di drenaggio. È stata inoltre considerata la presenza di eventuali angiomi cavernosi associati e l'eventuale correlazione con la sintomatologia.

Le sequenze SE Tl pesate dopo Gadolinio-DTPA in doppia dose sono risultate quelle con maggiore accuratezza diagnostica (score 77) sia rispetto alle sequenze basali (T1 score 12, T2 score 31) sia nei 24 pazienti sottoposti anche ad angio-RM (SE T1 dopo Gadolinio score 66, angio-RM score 61). L'angio-RM è risultata utile nell' evidenziare il tipo di drenaggio.

In 5 casi l'anomalia di sviluppo venoso era associata ad un angioma cavernoso, in 4 casi le due malformazioni erano in stretto rapporto; solo in due casi però l'angioma cavernoso presentava il tipico aspetto a «pop-corn». In un solo paziente l'anomalia venosa si è presentata come evento emorragico, mentre in un altro caso era in stretto rapporto con un'area di basso segnale in T1 e T2, esito di una pregressa emorragia.

Nel 34% i pazienti hanno presentato epilessia senza però una costante correlazione tra sede dell'ano-malia venosa e sede dell'anomalia elettroencefalografica.

Angioma venoso

Gli angiomi venosi sono malformazioni vascolari con esclusiva componente venosa, senza evidenza anatomopatologica nè angiografica di componenti arteriose o capillari. Diversi autori le considerano non vere e proprie malformazioni ma dilatazioni compensatorie in seguito ad anomalie di sviluppo, drenanti un territorio parenchimale normale. Presentiamo una serie di undid pazienti studiati mediante tomografia computerizzata ed angiografia selettiva, e in buona parte mediante risonanza magnetica, assieme ad una revisione della letteratura sull'argomento. Vengono presi in esame gli aspetti anatomoclinici di questo tipo di patologia, con considerazioni patogenetiche, e gli aspetti di diagnostica strumentale, ormai sufficientemente consolidati. Restano aperte le considerazioni di ordine terapeutico, in particolare in relazione alla opportunità di trattamento chirurgico.

Contrast-enhanced MR imaging in neuroimaging

MR imaging without and with gadolinium-based contrast agents (GBCAs) is an important imaging tool for defining normal anatomy and characteristics of lesions. GBCAs have been used in contrast-enhanced MR imaging in defining and characterizing lesions of the central nervous system for more than 20 years. The combination of unenhanced and GBCA-enhanced MR imaging is the clinical gold standard for the noninvasive detection and delineation of most intracranial and spinal lesions. MR imaging has a high predictive value that rules out neoplasm and most inflammatory and demyelinating processes of the central nervous system.

Pathomechanisms of Symptomatic Developmental Venous Anomalies

Background and Purpose— Although it is generally accepted that developmental venous anomalies (DVAs) are benign vascular malformations, over the past years, we have seen patients with symptomatic DVAs. Therefore, we performed a retrospective study and a literature study to review how, when, and why DVAs can become clinically significant.

Methods— Charts and angiographic films of 17 patients with DVAs whose 18 vascular symptoms could be attributed to a DVA were selected from a neurovascular databank of our hospital. MRI had to be available to rule out any other associated disease. In the literature, 51 cases of well-documented symptomatic DVAs were found. Pathomechanisms were divided into mechanical and flow-related causes.

Results— Mechanical (obstructive or compressive) pathomechanisms accounted for 14 of 69 symptomatic patients resulting in hydrocephalus or nerve compression syndromes. Flow-related pathomechanisms (49 of 69 patients) could be subdivided into complications resulting from an increase of flow into the DVA (owing to an arteriovenous shunt using the DVA as the drainage route; n=19) or a decrease of outflow (n=26) or a remote shunt with increased venous pressure (n=4) leading to symptoms of venous congestion. In 6 cases, no specific pathomechanisms were detected.

Conclusions— Although DVAs should be considered benign, under rare circumstances, they can be symptomatic. DVAs, as extreme variations of normal venous drainage, may represent a more fragile venous drainage system that can be more easily affected by in- and outflow alterations. The integrity of the DVA needs to be preserved irrespective of the treatment that should be tailored to the specific pathomechanism.

Cerebral venous angioma of the pons complicated by nonhemorrhagic infarction

✓ The authors emphasize an unusual complication of venous angiomas in the brain: venous infarction. The patient in this case is a 32-year-old man who presented with a clinical history of headache followed by a worsening of his neurological status. Neuroimaging studies demonstrated a brain infarct in the posterior fossa, which was related to thrombosis of the draining vein of a cerebral venous angioma. A conservative treatment approach without anticoagulation therapy was followed and the patient completely recovered. Nonhemorragic venous infarction caused by thrombosis of a venous angioma is exceptional and only nine previous cases have been reported in the literature.

Cavernous-venous malformation of brain stem--report of a case and review of literature

BACKGROUND

Because of improved imaging techniques, the association of cavernous and venous malformations is now being seen more often in neurosurgical practice. However, only a few cases have been subjected to surgery. Surgical excision of the cavernous malformation, sparing the venous component, has been the method of choice advocated by most authors. This, however, is not possible when the components are intimately associated with each other. It thus becomes important to predict the surgical outcome in such lesions, especially when they are located in an eloquent area. A surgically excised case of cavernous-venous malformation in the dorsal pontomedullary region is presented here; the histology confirmed the intimate association of both components. The relevant literature is also discussed.

CASE DESCRIPTION

This 20-year-old male presented with episodic vomiting, giddiness, and persistent cerebellar signs over a six-year period. Neuroimaging studies-computed tomography scan/magnetic resonance imaging (CT/MRI) were suggestive of a cavernous malformation. MRI also showed a draining vein close to the lesion. Following total excision, histopathology confirmed the intimate association of both cavernous and venous malformations. The patient made an uneventful recovery. MRI at follow up confirmed total excision.

CONCLUSIONS

The presence of venous channels draining into a lesion that otherwise appears to be a cavernous malformation may indicate an intimately associated venous component. Selective surgical excision of the cavernous component may be difficult in such cases. Surgical outcome, though favorable in this case, will be difficult to comment upon unless more such cases are reported. This may be of greater significance in lesions located in eloquent areas.

Cerebral venous angiomas associated with hemorrhagic lesions. Their MRI manifestations

Using two 1.5-T magnetic resonance (MR) scanners, 82 venous angiomas (VAs) were imaged. There were 13 (16%) VAs associated with hemorrhagic lesions. Ten of the 13 hemorrhagic lesions were considered hematomas in the subacute or chronic stage, caused by VAs or coexisting cavernous hemangiomas. Two of the 13 were subacute intracerebral hematomas; the remaining one was a sequela of a hemorrhagic venous infarct. After analysis of our data, it was concluded that infratentorial VAs and deeply draining supratentorial VAs in relatively young adults, especially females, are relatively frequently associated with intracerebral hemorrhagic lesions. MR imaging proved useful for diagnosing VAs and associated hemorrhagic lesions.

Intracranial vascular malformations

Intracranial vascular malformations are nonneoplastic developmental anomalies that present a variety of clinical patterns, ranging from asymptomatic to fatal intracranial hemorrhage. A practicing radiologist can expect to encounter these abnormalities, which include capillary telangiectasias, venous angiomas (also called developmental venous anomalies), cavernous angiomas, and arteriovenous malformations. The imaging findings that characterize these lesions are reviewed in this article, along with their pathological and clinical features.

Venous angiomas: plain and contrast-enhanced MRI and MR angiography

We studied 17 patients with venous angiomas, 4 of whom had associated cavernous angiomas. All underwent MRI with spin-echo T1- and T2-weighted images and T1-weighted images after Gd-DTPA; MR angiography (MRA) was also performed with 3D and 2D time-of-flight technique; 5 patients underwent conventional angiography. Contrast-enhanced MRI demonstrated all the lesions, showing the peripheral medullary veins, the collector and the type of drainage. Both 3D and 2D MRA provided diagnostic information identical to that obtained after infusion of Gd-DTPA. Contrast-enhanced were T1-weighted images and MRA superior in all the cases to images without gadolinium. The possible association with cavernous angiomas (24% in our study) indicates T2-weighted imaging.

Progression of multiple cryptic vascular malformations associated with anomalous venous drainage. Case report

The case of a young girl with a pericallosal venous malformation associated with multiple cryptic vascular malformations (CVM's) is described. The presenting cryptic malformation, which hemorrhaged, was completely excised, but the venous malformation was not. Routine follow-up magnetic resonance images obtained over the past 9 years have documented the development of multiple new cryptic malformations along the radicles of the venous malformation. Magnetic resonance imaging and cerebral angiography revealed venous outflow obstruction at the junction of the venous malformation with the straight sinus. The association of CVM's with anomalous venous drainage patterns and the role of venous hypertension in the pathogenesis of cryptic malformations are discussed. This case suggests that CVM's associated with a venous malformation may recur and new ones may develop if the venous malformation is not excised, particularly if venous hypertension is also present. The likelihood of a surgical cure in these patients may depend on complete excision of both anomalies, which is rarely feasible because of the potentially devastating results of resecting a venous malformation. Alternative treatments for patients with both types of lesions are discussed.

Cerebral venous angiomas: surgery as a mode of treatment for selected cases

Eleven patients with venous angiomas, 6 males and 5 females ranging in age from 4 to 58, are presented. Four patients presented with intracerebral haematoma and 3 patients had associated cavernous angioma, respectively. Patients with intracerebral haematoma had signs and symptoms due to the localization of the haematoma. The other patients presented with headache, seizures, vertigo, ataxia and mental disturbances. Pre-operative diagnosis was based on computerized tomography, magnetic resonance imaging and cerebral angiography. In 9 surgical cases it was confirmed by histopathological examination of operative specimens. After establishing the type, size and location of the lesion decision for operative treatment was made in nine cases, in four of them because of the presence of an intracerebral haematoma and in 5 of them due to severe disability. Eight of these 9 patients recovered completely and one improved. No severe cerebral oedema was encountered after converging medullary veins were excised and main draining veins partially coagulated. In this small series we encountered an unexpectedly large percentage of venous angiomas causing intracerebral haemorrhage which are commonly considered more benign than other vascular malformations. After reviewing previously reported cases of venous angiomas causing intracerebral haemorrhage and severe neurological deficit we think that the term "benign" is worth reconsidering. We propose a thorough examination of each case of venous angioma and the operative treatment when appropriate taking into account patients state and location of angioma.

Magnetic resonance angiography of cerebral developmental venous anomalies: its role in differential diagnosis

CT, MRI and contrast angiography of 20 patients with 21 developmental venous anomalies (DVAs), so-called venous angiomas, were compared with magnetic resonance angiography employing a two-dimensional time-of-flight technique (2D-MRA). MRA was diagnostic in 17 DVAs, when both the primary 2D slices and the maximum-intensity-projection images were read. Contrast angiography still provides the best visualization of both DVA components: dilated medullary veins and transcerebral draining vein; however, it is an invasive procedure and delivers no information about brain parenchyma. We regard MRI as necessary in cases with a suspected DVA because of the high rate of association with cavernomas: 33% in this study. Acute neurological symptoms were caused by haemorrhage from an associated cavernoma and not from the DVA in 4 such cases. Thus MRA combined with MRI obviates angiography in most cases and offers a noninvasive diagnostic strategy adequate for DVAs.

Posterior fossa venous anomaly and ipsilateral acoustic neuroma: two cases

The association of an acoustic neuroma with an ipsilateral venous anomaly or angioma is reported in two patients. In the first, the venous angioma was situated low in the posterior fossa, and was of no significance surgically. In the second, the angioma was strongly attached to the capsule of the tumour. On MRI and angiography the lesion appeared as a large draining vein, encircling the tumour. At operation, extensive dissection of the angioma from the neuroma appeared necessary to prevent venous infarction of the brain stem.

MR imaging and angiography of cerebral venous angiomas associated with brain tumors

MR study of 6 patients with concurrent venous angioma and brain tumor revealed that in 2 of the 6 cases, the draining vein of the venous angioma was located near to the tumor and was displaced by the tumor. Two of the 6 venous angiomas were too small to visualize prior to contrast enhancement, but could be detected following administration of Gd-DTPA. Angiography was required for definitive diagnosis of the venous angiomas. When a venous angioma is suspected or is detected incidentally, especially when very near a brain tumor, angiography should be considered before performing surgery to avoid surgical complications. Otherwise, ligation of the vein draining the venous angioma may lead to venous infarction.