Kwang Kuk Kim^b
bDepartment of Neurology
University of Ulsan
College of Medicine
Asan Medical Center
Seoul, Korea

Venous congestive myelopathy (VCM) often results from impaired venous outflow secondary to a spinal arteriovenous malformation.^1,2 Foix-Alajouanine syndrome, also known as subacute necrotizing myelopathy or angiodysgenetic necrotizing myelopathy, is the term formerly used to describe this progressive myelopathy. One of the causes is known to be spinal dural arteriovenous fistula (SDAVF).³

McKeon et al. described the key diagnostic features that lead to the early diagnosis of SDAVF as follows: 1) a progressive rather than a subacute course; 2) the presence of abnormal, dilated vessels surrounding the cord on standard T2 sagittal MRI with subsequent confirmation of SDAVF with angiography; and 3) acute worsening even with corticosteroid therapy.⁴ Although they clearly described three features, at least two of them must be corrected because their wrong explanation may provide confusion leading to inappropriate management of this disease. The main reason of such inappropriate explanation seems to be derived from misunderstanding on the cause of VCM.

First, their description revealed confusion when describing the difference between SDAVF and VCM. SDAVF is the most common cause of VCM. However, SDAVF causes VCM as it is caused by regurgitation of fistular flow through the radicular vein to the perimedulary venous plexus. Therefore, VCM can be caused by any kind of spinal vascular malformation, even in pial (Fig 1) or epidural arteriovenous fistulas.⁵ Whatever spinal or paraspinal vascular malformations are related to VCM, disconnection of such regurgitation should be a primary target of the definitive treatment for VCM.

Second, they mention that acute worsening of neurological deficit with corticosteroid therapy occurs in SDAVF.  Although such aggravation can be a feature of SDAVF, it is not always observed and sometimes there is improvement or no change in the neurological deficit.² Once again, acute worsening with corticosteroid therapy occurs not only in SDAVF but also in VCM.

In the very late phase of VCM, there is diffuse spinal cord enhancement after gadolinium administration. In those patients, spinal cord atrophy associated with myoclonus can remain even after successful treatment, probably resulting from the venous infarction caused by prolonged VCM.⁶ Such venous infarction might differ in its extent and clinical presenting symptom pattern from those of other vascular territories of arterial infarction⁷ or from specific spinal cord lesion involvement due to other causes.⁸

References

1.    Rodriguez FJ, Crum BA, Krauss WE, Scheithauer BW, Giannini C. Venous congestive myelopathy: a mimic of neoplasia. Mod Pathol 2004;18:710-8

2.    Lee C-S, Pyun HW, Chae EY, Kim K-K, Rhim SC, Suh DC. Reversible Aggravation of Neurological Deficits after Steroid Medication in Patients with Venous Congestive Myelopathy Caused by Spinal Arteriovenous Malformation. Interventional Neuroradiology 2009;15:325-9

3.    Mirich DR, Kucharczyk W, Keller MA, Deck J. Subacute necrotizing myelopathy: MR imaging in four pathologically proved cases. AJNR Am J Neuroradiol 1991;12:1077-83

4.    McKeon A, Lindell EP, Atkinson JL, Weinshenker BG, Piepgras DG, Pittock SJ. Pearls & Oy-sters: Clues for spinal dural arteriovenous fistulae. Neurology 2011;76:e10-2

5.    Suh DC, Choi CG, Sung KB, Kim KK, Rhim SC. Spinal osseous epidural arteriovenous fistula with multiple small arterial feeders converging to a round fistular nidus as a target of venous approach. AJNR Am J Neuroradiol 2004;25:69-73

6.    Caviness JN, Brown P. Myoclonus: current concepts and recent advances. The Lancet Neurology 2004;3:598-607

7.    Suh DC, Kim SJ, Jung SM, Park MS, Lee JH, Rhim SC. MRI in presumed cervical anterior spinal artery territory infarcts. Neuroradiology 1996;38:56-8

8.    Suh DC, Yoo SJ, Park YS, Hong CY, Choi HY, Moon WY. MR features in patients with residual paralysis following aseptic meningitis. AJNR Am J Neuroradiol 1991;12:1234-7

To access your free subscription please visit our website

www.interventionalneuroradiology.it

and login with the

user: inrdigital@centauro.it

password: inuro-11

Thank you for your ongoing support of Interventional Neuroradiology.

Warmest regards,

Marco Leonardi

Professor of Neuroradiology

Bologna University, Italy

American Journal of Neuroradiology 32:E51-E52, March 2011
© 2011 American Society of Neuroradiology

R.V. Chandra^a, T.M. Leslie-Mazwi^a and D. Oh^a
aDepartment of Interventional Neuroradiology and Endovascular Neurosurgery

B. Mehta^b
bDepartment of Neurocritical Care

A.J. Yoo^c
cDepartment of Diagnostic and Interventional Neuroradiology
Massachusetts General Hospital
Harvard Medical School
Boston, Massachusetts

We commend Cuvinciuc et al¹ on their recent review of nontraumatic cortical subarachnoid hemorrhage (cSAH). While not an uncommon clinical presentation, there is an overall paucity of literature on this subject, with the largest reported series by Kumar et al² comprising only 29 patients. Cuvinciuc et al¹ suggested that cSAH may occur in the setting of high-grade atherosclerotic stenosis of the extracranial cerebral arteries, potentially by a mechanism similar to cSAH in Moyamoya disease (eg, rupture of fragile dilated pial collateral vessels). Recently 3 cases of cSAH have been described in association with bilateral cervical internal carotid artery (ICA) stenosis,³ and 2 further cases, in the setting of acute ICA occlusion during ischemic stroke.⁴We describe a rare case of unilateral extracranial ICA stenosis associated with cSAH and discuss the angiographic findings that support the postulated mechanism of fragile pial collateral vessels.

A 70-year-old man experienced a sudden onset of transient aphasia and dysarthria, along with right face and arm numbness at a systolic blood pressure of 200 mm Hg. Noncontrast CT demonstrated isolated cSAH in the left central sulcus (Fig 1), and CT angiography (CTA) revealed an 80% left ICA-origin stenosis without evidence for arterial or venous cause of the cSAH. He continued to have recurrent events in the hospital and was managed for possible transient ischemia or seizure with intravenous anticoagulation and seizure prophylaxis, respectively. MR imaging excluded acute infarction, posterior reversible leukoencephalopathy, amyloid angiopathy, or an underlying mass. There was no clinical evidence of endocarditis, with negative findings on blood cultures and a normal finding on transthoracic echocardiogram. Continuous electroencephalographic monitoring during these episodes did not reveal epileptiform correlation during briefly symptomatic episodes that remained similar to those on the initial presentation.Given the frequency of transient symptoms, carotid endarterectomy (CEA) was considered for the ipsilateral stenosis. However, it was imperative to definitively rule out any vascular lesions responsible for the cSAH, which could worsen from potential hyperperfusion syndrome following CEA. Cerebral angiography was performed and demonstrated no evidence of vasculitis, reversible cerebral vasoconstriction syndrome, mycotic aneurysm, or arteriovenous malformation.

Of note, the 80% left ICA-origin stenosis (Fig 2) resulted in a shift of the angiographic watershed between the left middlecerebral artery (MCA) and posterior cerebral artery (PCA) territories toward the central sulcus (Fig 3). Most importantly, there was minimal collateral support via the circle of Willis. A hypoplastic precommunicating right anterior cerebral artery (ACA) segment provided minimal flow across the anterior communicating artery. No left posterior communicating artery was discernible. Subsequently, the patient underwent emergent ipsilateral CEA with resolution of his symptoms.

Isolated cSAH in the present case, the 3 cases with bilateral ICA stenosis described by Kleinig et al,³ and the 2 cases ofacute ICA occlusion described by Geraldes et al,⁴ all occurred on the symptomatic side or the side with the more severe anatomic narrowing (stenosis or occlusion). All 6 patients were acutely symptomatic suggesting that cSAH may derive from an acute alteration in hemodynamics (eg, plaque rupture and further atherothrombotic narrowing or acute hypertension). We propose that this hemodynamic stress may damage already maximally dilated pial collateral vasculature and produce cSAH.

This idea is supported by our angiographic findings, in which the subarachnoid hemorrhage colocalized to the watershed region between the MCA and PCA territories. In the setting of severe ICA stenosis or occlusion, it is the MCA-PCA watershed rather than the MCA-ACA watershed that may be particularly prone to this phenomenon, because the ipsilateral ACA and MCA have reduced perfusion pressure and are less able to respond to acute hemodynamic failure, particularly in the absence of sufficient blood flow via the anterior or posterior communicating arteries as in this case. On the other hand, the normally perfused PCA territory is able to mount a compensatory increase in perfusion pressure, which may rupture fragile pial collateral vessels in the watershed. Consistent with this idea, 4 of the 6 described cases occurred in a perirolandic location, at the watershed between the MCA and PCA territories.

The rarity of cSAH in the setting of unilateral extracranial ICA stenosis may reflect the collateral pathways across the circle of Willis that are usually present. As in our case, the absence of adequate collaterals may provide a clue to this mechanism of cSAH. Contrary to Cuvinciuc et al,¹ who advocated only brain vascular imaging, CTA evaluation of cSAH must include the cervical vasculature, lest a high-risk yet treatable lesion is missed.

References

1. Cuvinciuc V, Viguier A, Calviere L, et al. Isolated acute nontraumatic cortical subarachnoid hemorrhage. AJNR Am J Neuroradiol 2010;31:1355–62[Abstract/Free Full Text]
2. Kumar S, Goddeau RP, Jr, Selim MH, et al. Atraumatic convexal subarachnoid hemorrhage: clinical presentation, imaging patterns, and etiologies. Neurology 2010;74:893–99[Abstract/Free Full Text]
3. Kleinig TJ, Kimber TE, Thompson PD. Convexity subarachnoid haemorrhage associated with bilateral internal carotid artery stenoses. J Neurol 2009;256:669–71[CrossRef][Medline]
4. Geraldes R, Santos C, Canhao P. Atraumatic localized convexity subarachnoid hemorrhage associated with acute carotid artery occlusion. Eur J Neurol 2011;2:e28–e29

Reply

Published ahead of print on February 24, 2011
doi: 10.3174/ajnr.A2559

American Journal of Neuroradiology 32:E53, March 2011
© 2011 American Society of Neuroradiology

V. Cuvinciuc^a and F. Bonneville^a
aDepartment of Neuroradiology

A. Viguier^b
bDepartment of Vascular Neurology
Rangueil University Hospital
Toulouse, France

We thank Chandra et al for their contribution in detailing the angiographic findings of extracranial internal carotid stenosis associated with cortical subarachnoid hemorrhage (cSAH). Our postulated mechanism of rupture of fragile dilated collateral pial vessels is supported by their findings of severe extracranial internal carotid artery stenosis, angiographic visualization of dilated pial anastomoses, the borderline topography of cSAH (in the same area as the dilated pial anastomoses), and the absence of other potential causes.

Autoregulatory vasodilation is a compensatory mechanism for decreases in cerebral perfusion pressure in patients with unilateral chronic steno-occlusive disease. It would be interesting to have, in this setting, a functional examination for evaluation of cerebral vascular reserve. Different techniques exist (eg, positron-emission tomography, single-photon emission CT, and,more widely available, CT perfusion with acetazolamide challenge).^1,2 We suppose that fragile dilated collaterals would be associated with a depletion of the cerebral vascular reserve, with very limited reactivity after acetazolamide challenge compared with the contralateral side.

In our clinical routine, we prefer performing a brain CT angiography for patients with cSAH, and if negative, it is completed with cervical contrast-enhanced MR imaging or CT angiography to evaluate the presence of this rare association of a cSAH and an extracranial carotid artery stenosis. Angiography should remain reserved for selected cases only.

References

1. Kim E, Sohn CH, Na DG, et al. Perfusion computed tomography evaluation of cerebral hemodynamic impairment in patients with unilateral chronic steno-occlusive disease: a comparison with the acetazolamide challenge 99mTc-hexamethylpropyleneamine oxime single-photon emission computed tomography. J Comput Assist Tomogr 2009;33:546–51[CrossRef][Medline]
2. Chen A, Shyr MH, Chen TY, et al. Dynamic CT perfusion imaging with acetazolamide challenge for evaluation of patients with unilateral cerebrovascular steno-occlusive disease. AJNR Am J Neuroradiol 2006;27:1876–81[Abstract/Free Full Text]

Re: Piotin M, Blanc R, Spelle L, Mounayer C, Piantino R, Schmidt PJ, Moret J. Stent-Assisted Coiling of Intracranial Aneurysms. Clinical and Angiographic Results in 216 Consecutive Aneurysms. Stroke 2010;41:110-15; published online before print December 3 2009, doi:10.1161/STROKEAHA.109.558114

However, some of us propagate a more liberal use of intracranial stents because the stent should attribute to a more durable aneurysm occlusion on the long-term by diverting the flow and by creating a mesh at the level of the neck to be colonized and covered by endothelial cells. In view of these perceived advantages, some even place a stent after successful aneurysm occlusion by simple coiling. The key question in this issue is: Does the potential better long-term result with use of stents negate the higher expected rate of complications?

One answer to this question is provided by the recently published study by Piotin. Clinical and imaging results of 216 patients with aneurysms (181unruptured and 35 ruptured) that were treated with stent assistance were compared to results of 1109 aneurysms (549 ruptured and 560 unruptured) that were treated without stent. Permanent neurological procedure-related complications occurred in 7.4% (16 of 216) of the procedures with stents versus 3.8% (42 of 1109) in the procedures without stents. Procedure-induced mortality occurred in 4.6% (10 of 216) of the procedures with stents versus 1.2% (13 of 1109) in the procedures without stents. In other words, with stent assisted treatment, 12% of patients either died or had permanent neurological deficit as a direct consequence of the treatment. How about the angiographic results, are these better with stent than without stent? Aneurysms treated with a stent had a higher rate of initial incomplete occlusion (35% versus 18%). Only about half of the stented aneurysms had angiographic follow-up and there were less recurrences 15% (17 of 114) versus 34% (259 of 774).

Unfortunately, the authors did not further analyse the high rate of complications with stent assisted coiling (vessel perforations, aneurysm perforations, thrombo-embolic complications). They also did not provide a definition of a recurrence and more important, the rate of retreatment in both groups was not reported. Although there were fewer recurrences after stenting, the recurrence rate of 15% with stent assistance is within the normal range of 10-20% reported for coiling in general.

The results of the study by Piotin give a clear answer to our previous question: the complication rate of stent assisted coiling is alarmingly high in a population harboring mostly unruptured aneurysms located on sites that are easily accessible for surgery while the follow-up results are comparable to results of coiling in general.

In my opinion, the use of this dangerous stent-assisted coiling should be discouraged and restricted to those cases where a stent is absolutely necessary and no alternative treatment is available. For sure, placement of a stent after successful coiling should be deterred since by placing the stent the procedure is converted from low-risk to high-risk.

Finally, we should not blame the bad handling of the device for the increased complication rate; it is always the operator who decides what materials to use. The introduction of newer stents with safer handling is not an excuse for denying disappointing results.

1. How many people regularly do cervical nerve root blocks?
2. Are you using CT or conventional fluoro?
3. If you are using CT, do you use contrast to confirm needle position?

It would be great for people to comment on the blog, but you can also email me directly.

Thanks!
jenny.hoang@duke.edu

The authors analyzed the long-term stability of treatment of cerebral aneurysms treated exclusively with GDC, focusing in re-treatments and re-bleeding rates during follow up.

The authors have been meticulous in data recollection, once, these patients have been followed since 1998. Additionally, the fact to be a multicentric trial, demands a greater author commitment for the patients follow up, according to strict designed protocol.

The experience presented here, is the continuum of the data reported by the authors previously in 2005 and 2008 in this journal. Now, nevertheless, the totality of the series including unruptured and ruptured intracranial aneurysms. The authors describe the radiological findings in a considerable sample of 1036 aneurysms treated in 929 patients, with a mean of follow up of 66 months and, a very significant number over than 400 aneurysms followed more than five years.

The results of this multicentric trial must be analyzed cautiously, before to be extrapolated as part of the standard treatment of “aneurysms”. In this experience near 90% of lesions were smaller of 10 mm, and, only 2% of the lesions were giant and therefore, similar to reports of ISAT, these results could be validated just for a sub-type of patients with small aneurysms of the anterior circulation, in a good clinical status, that after a multidisciplinary evaluation were defined as good candidates to endovascular treatment , thus, there was an important selection bias and, unfortunately, exclude those lesions that have an elevated risk of treatment failure.

In this report, as well as previous publications, the authors unfortunately did not describe the characteristics of the parent vessel and his relation with the neck of the aneurysm; the dome: neck ratio was not considered and presumably, due to high rate of effectiveness reported, one would suppose that the majority of lesions had small neck or at least a favorable dome: neck ratio; although 10% required balloon remodeling assisted technique.

Regarding re-treatment group, there is lack of morphological data (i.e. size, neck diameter, Location) to analyze if, with the current endovascular technology available, these numbers could dramatically be reduced. Hence, special consideration is necessary to evaluate the 731 aneurysms that initially showed a complete occlusion, given that, it is in this group of lesions in where, really it is reflected the treatment stability over-time. Once removed the patients who died and those that were lost during the follow up, a total of 611 aneurysms was finally followed and of these, 109 (17,8%) showed a negative variation during follow up (Subtotal or incomplete) according to illustrated in table 4. Although, this result it’s in agreement with published data regarding recanalization/regrowth rates, it’s remarkably that the majority of aneurysms were small lesions , with apparent favorable dome: neck ratio and, would be expected a better result. However, these results refer to think that a greater volumetric filling and/or, the use of biological materials that promotes a more stable intra-aneurysmal thrombosis may perhaps reduce these numbers even more.

The re-bleeding rate did not surpass 1% , this demonstrates once again that the endovascular treatment of cerebral aneurysms with GDC is effective and clinically protective. But, at the same time it generates the question about the necessity of re-treatment and what are the criteria for the decision making. Currently, there is not an objective, validate and, reproducible methodology to evaluate the immediate initial occlusion and, comparatively help us to interpret the morphologic changes over the time. The work of the authors with this cohort of patients will continue generating valuable information to the world of Neurointerventionism and bring answers to this nascent specialty.

Pedro Lylyk MD.

I’m an interventional neuroradiologist in South Korea. Korea’s health insurance service inquired of the Korean Society of Interventional Neuroradiology what is the qualification of neurointerventionist for payment of interventional procedure.

I want to know certification requirements for neurointervention in America.

Does the insurance company require the other certification as well as ABR or institutional certification of fellowship?

Does anyone know what this mass could be? It was biopsied 2 years ago and pathology reported it as  “normal brain tissue”.

As you can see, the lesion is hyperintense on T2, hypointense on T1 and does not enhance.  No calcifications are present and no there is no restricted diffusion .

The patient is 25  year old and has loss of short term memory and seizures.

Any input into the nature of the mass is welcome.