Editor’s and Fellows’ Journal Club Choices, March 2010

Editor’s Choices

Occurrence and Predictors of Futile Recanalization Following Endovascular Treatment among Patients with Acute Ischemic Stroke: A Multicenter Study • H.M. Hussein, A.L. Georgiadis, G. Vazquez, J.T. Miley, M.Z. Memon, Y.M. Mohammad, G.A. Christoforidis, N. Tariq, and A.I. Qureshi
Despite the fact that arterial recanalization is the principal goal of endovascular treatment in acute stroke patients many fail to get clinically better. Why? This is the question addressed by these investigators who basically analyzed the existing literature in this topic. Patients received pharmacological and/or mechanical thrombectomies. The authors tried to establish the cause of poor clinical outcome despite complete angiographic recanalization. Nearly 1/3 of patients underwent IA thrombolysis and recanalization, and their results were fruitless in one half of them. Factors associated with futile recanalization included older age, involvement of the basilar artery, higher median NIHSS scores and hemorrhage. Of these, those factors that were statistically significant included older age and lower initial NIHSS scores (severe neurological symptoms).

Late Adverse Events in Coiled Ruptured Aneurysms with Incomplete Occlusion at 6-Month Angiographic Follow-Up • S.P. Ferns, C.B.L.M. Majoie, M. Sluzewski, and W.J. van Rooij
Late complications of aneurysm coil embolization include rebleeding, complications of diagnostic angiography, and progressive mass effect from lesion growth. The authors restrospectively looked at over 900 coiled aneurysms at their 6-month follow-up. Of these, 124 were incompletely occluded and 71% were retreated. They did over 300 diagnostic follow-up angiograms without complications. Four aneurysms rebelled (2 patients died) and 4 regrew (1 died) giving complication annual rates as follows: overall events (1.9%), mortality (0.7%) and rebleeding (1.0%). The authors concluded that angiographic follow-up and recoiling can be done with little harm to the patient and that complications were only related to rebleeding and aneurysm regrowth.

Nonenhancing Intramedullary Astrocytomas and Other MR Imaging Features: A Retrospective Study and Systematic Review • H.S. Seo, J.-h. Kim, D.H. Lee, Y.H. Lee, S.-i. Suh, S.Y. Kim, and D.G. Na
Most of us have been taught that by the time of their discovery all intramedullary tumors show contrast enhancement. The authors did a retrospective review of non-enhancing spinal cord tumors obtained from 4 different institutions. They found 19 patients with cord astrocytomas and analyzed their patterns of contrast enhancement. They found 6 astrocytomas and 2 anaplastic astrocytomas that did not enhance. All other tumors showed some contrast enhancement. They then analyzed the literature and from it concluded that 18% of intramedullary primary tumors do not enhance. Thus, non-enhancing astrocytomas (20-30%) are not rare and should be included in the differential diagnosis of expansile non-enhancing cord masses. This is clearly not my experience, and the findings surprised me.

Diffusely Abnormal White Matter in Progressive Multiple Sclerosis: In Vivo Quantitative MR Imaging Characterization and Comparison between Disease Types • H. Vrenken, A. Seewann, D.L. Knol, C.H. Polman, F. Barkhof, and J.J.G. Geurts
We all know that white matter in MS patients is diffusely affected. Can this diffuse involvement be measured using quantitative MR techniques? Which technique is better for this purpose? In this study, the authors used 4 different techniques (T1 maps, magnetization transfer ratios, ADC and fractional anisotropy) to assess white matter changes and attempted to correlate their results with the type of MS. They found that all four techniques showed abnormal results in the white matter of MS patients. Furthermore, they found that these measurements differ for patients with primary progressive and secondary progressive multiple sclerosis.

Fellows’ Journal Club

Diffusion MR Imaging of Hypoglycemic Encephalopathy • E.G. Kang, S.J. Jeon, S.S. Choi, C.J. Song, and I.K. Yu
Brain imaging findings in adult hypoglycemia are not well established, and here, the authors retrospectively reviewed the MRI features seen in 11 such patients. The areas found to be most severely affected using conventional MR images and DWI (with ADC measurements) were the posterior limbs of the internal capsules, hippocampi, and basal ganglia. In these regions, ADC values were about 50% of normal. In 6 patients the imaging findings resolved and they did well. Patients with cortical or white matter involvement affecting more than one lobe did poorly or died. The lesions that resolved did so very quickly and were probably related to reversible cytotoxic edema.

Cerebral Venous Thrombosis: Diagnostic Accuracy of Combined, Dynamic and Static, Contrast-Enhanced 4D MR Venography • S. Meckel, C. Reisinger, J. Bremerich, D. Damm, M. Wolbers, S. Engelter, K. Scheffler, and S.G. Wetzel
Although cerebral venous thrombosis is probably a common disease, the optimal MR techniques to assess it are uncertain. Here the authors looked at the 39 patients who underwent brain imaging using 4D-MRC, 2D-time-of-flight MRV, gradient echo imaging, T2-weighted sequences. When evaluating thrombosed venous sinuses 4D-MRV did best. For cortical vein thrombosis the best sequences were 4D-MRV and the TOF MRV. The same was true for patients with chronic sinus thrombosis. For isolated cortical vein thrombosis, GRE images were the best. Overall, all modalities did well with specificities ranging from 96-99%. This article contains supplemental movies found online only.

Perfusion CT in Squamous Cell Carcinoma of the Upper Aerodigestive Tract: Long-Term Predictive Value of Baseline Perfusion CT Measurements • S. Bisdas, Z. Rumboldt, K.S. Popovic, M. Baghi, T.S. Koh, T.J. Vogl, and M.G. Mack
These authors sought to find a relationship between perfusion CT results in patients with squamous cell cancers of the head and neck and their survival rates. 84 patients treated with chemoradiation were assessed with maps of blood flow, blood volume, MTT and permeability. Blood volume and permeability were higher in those patients with longer control periods and both parameters were predictive of local tumor control. Thus, higher blood flow and permeability and a mismatch between blood volume and flow predict a good outcome. Please listen to February’s podcast for more information regarding this subject.

Changes in Perfusion CT of Advanced Squamous Cell Carcinoma of the Head and Neck Treated during the Course of Concomitant Chemoradiotherapy • K. Surlan-Popovic, S. Bisdas, Z. Rumboldt, T.S. Koh, and P. Strojan
This is another article from the same group of investigators as the previous one (see above). In this one, the authors looked at similar parameters but in a group (20 patients) with locally advanced head and neck squamous cell cancers, which were treated with chemoradiation. As expected, tumor volumes were reduced regardless of radiation dose in responders. In responders, significant reductions in blood volumes were seen while changes in all other parameters were not significant. It seems that in this group of patients, blood volume maps were better predictors than blood flow and MTT (somewhat different than in their previous study). Thus, CT perfusion results as they relate to prognosis may be different for advanced tumors when compared to more local ones.

Editor’s and Fellows’ Journal Club Choices, March 2010