Editor’s Choices

Intracranial Dural Arteriovenous Fistula with Retrograde Cortical Venous Drainage: Use of Susceptibility-Weighted Imaging in Combination with Dynamic Susceptibility Contrast Imaging • K. Noguchi, N. Kuwayama, M. Kubo, Y. Kamisaki, K. Kameda, G. Tomizawa, H. Kawabe, and H. Seto
In my experience, nearly all patients with dural arteriovenous fistulas have normal MR imaging studies unless they have cortical venous reflux. These authors used susceptibility-weighted imaging to evaluate such patients and compared the findings with those shown by gadolinium MR perfusion studies. They studied 10 individuals who by digital subtraction angiography had dural AVFs with cortical venous drainage. One hundred percent of patients showed cortical vein abnormalities on SWI and 9% had involvement of the deep veins. All showed perfusion abnormalities (increased cerebral blood volume). All SWI and perfusion abnormalities were located in similar territories. Conclusion: SWI in combination with MR perfusion may be useful in the evaluation of cortical venous drainage in patients with dural AVFs. Maybe the authors will repeat these studies after they treat the AVFs and let us know if both techniques can be used to evaluate the success (or failure) of treatment.

Long-Term Outcome in the Repair of Spinal Cord Perimedullary Arteriovenous Fistulas • L. Antonietti, S.A. Sheth, V.V. Halbach, R.T. Higashida, C.F. Dowd, M.T. Lawton, J.D. English, and S.W. Hetts
Here’s another article on a similar topic as the previous one, but this time involving spinal AVFs. In this paper the authors evaluated the long-term prognosis of type 4 spinal AVFs (that is, those that are intradural/extramedullary [which are very rare]). During a 26-year period the authors treated 32 patients and then evaluated the long-term effects of treatment on ambulation and micturition. Interesting fact: only 4 patients were successfully treated with embolization alone, 15 had embolization and surgery, and 11 surgery only. Six showed residual fistula on follow-up angiography and this group had the worst neurologic outcome of all. Among the remaining patients, significant improvements in ambulation but not in micturition were documented. Therefore, treatment is definitively indicated as all patients showed some improvement.

Functional MR Imaging in Patients with Carotid Artery Stenosis before and after Revascularization • M. Schaaf, G. Mommertz, A. Ludolph, S. Geibprasert, G. Mühlenbruch, M. Das, and T. Krings
Carotid endarterectomy is known to reduce the risk of stroke and improve outcomes. What is its effect on cerebral vascular reactivity? Can cerebral vascular reactivity be objectively used to evaluate the results of CEA? Here, the investigators used blood oxygen level–dependent functional MR imaging in 19 patients. Thirteen were symptomatic and 6 were not. fMRI studies involving motor tasks were done before and after CEA. Mean BOLD signal increased significantly after CEA (> 80%). This finding was even more pronounced in patients who had previous infarctions and in those older than 70 years. The authors concluded that changes seen on fMRI were indicative of ameliorated cerebral vascular reactivity but that this improvement depends on age of the patient, degree of preoperative stenosis, and the patient’s symptoms.

Fellows’ Journal Club

Cervical and Intracranial Arterial Anomalies in 70 Patients with PHACE Syndrome • C.P. Hess, H.J. Fullerton, D.W. Metry, B.A. Drolet, D.H. Siegel, K.I. Auguste, N. Gupta, A.N. Haggstrom, C.F. Dowd, I.J. Frieden, and A.J. Barkovich
This is probably the world’s largest series of patients with PHACE (it includes images from 5 different institutions). The authors looked at MR angiography and/or CT angiography studies in 70 patients from an anatomic standpoint and then tried to “explore” the relationship between the vascular anomalies seen and underlying structural brain anomalies (they had MR studies of the brain in 59 patients). All patients had vascular anomalies involving the circle of Willis or the arteries in the neck and the most common findings included dysgenesis, anomalous course or origin of vessels, narrowing, and non-visualization. Hemangiomas ipsilateral to the previously mentioned vascular anomalies were present in all but one patient, with involvement most often seen in the frontotemporal and mandibular regions. All patients with anomalies of the cerebellum showed patent primitive communications between the carotid-basilar systems. Fellows should carefully evaluate the brains and vascular structures in patients harboring large facial hemangiomas as they may be the first to make the diagnosis of PHACE.

Sonographic Differentiation of Asymptomatic Diffuse Thyroid Disease from Normal Thyroid: A Prospective Study • D.W. Kim, C.K. Eun, H.S. In, M.H. Kim, S.J. Jung, and S.K. Bae
When is a large thyroid gland normal and when is it abnormal? This is a difficult question regardless of which imaging technique you are using. Here the authors used ultrasound to differentiate asymptomatic, diffusely enlarged, and diseased thyroid glands from those that were just large but otherwise normal. They evaluated more than 2000 patients and asked radiologists to broadly categorize the glands as suspicious, indeterminate, or normal. They correlated these categories with biopsy findings in 340 instances. The results were as follows: sensitivity was 87.7%, specificity 92.1%, positive predictive value 70.4%, negative predictive value 97.2%, and accuracy 91.3%. The most common diseases were: chronic lymphocytic thyroiditis and diffuse hyperplasia. The authors concluded that their classification was useful for differentiating large abnormal vs. large but otherwise normal thyroid glands.

Apparent Diffusion and Fractional Anisotropy of Diffuse Intrinsic Brain Stem Gliomas • H.J. Chen, A. Panigrahy, G. Dhall, J.L. Finlay, M.D. Nelson, Jr, and S. Blüml
Despite being histologically benign, diffuse intrinsic brain stem gliomas have a terrible prognosis. Can apparent diffusion coefficient values tell us something about the nature of these tumors and their responses to different therapies? In 9 patients with 24 follow-up studies, the authors assessed ADCs (at 5 different locations) and correlated these with similar values obtained in patients with medulloblastoma, juvenile pilocytic astrocytoma, and normal controls. Their initial observations make sense: ADC was higher in DIBSGs than in medulloblastomas and JPAs but lower than in the normal brain stem (due to relative hypercellularity). Fractional anisotropy values increased after radiation therapy, correlated with better survival, and were better markers of disease when obtained at the midbrain level. ADC changes in these tumors after therapy were thought to be predominantly related to decreasing edema and not tumor regression. Conclusion: ADC values may be useful in the follow-up of these devastating tumors.