Editor’s Choices

Flat Detector CT in the Evaluation of Brain Parenchyma, Intracranial Vasculature, and Cerebral Blood Volume: A Pilot Study in Patients with Acute Symptoms of Cerebral Ischemia • T. Struffert, Y. Deuerling-Zheng, S. Kloska, T. Engelhorn, C.M. Strother, W.A. Kalender, M. Köhrmann, S. Schwab, and A. Doerfler
Flat detector technology may be the future of CT and though it has been used in the angiographic suite, its utility as the initial study in patients with acute stroke symptoms has not been fully evaluated. Here, the authors tested the hypothesis that FD-CT provides good anatomic and physiologic information that correlates well with that obtained by conventional CT. FD-CT including CT angiography and cerebral blood volume was performed in 10 patients who also underwent a similar battery of studies with conventional CT. With respect to perfusion, color maps, and absolute values, both techniques showed good correlation. All vascular lesions were seen with both techniques and only visualization of the brain parenchyma was better with conventional CT.

Acute Hepatic Encephalopathy: Diffusion-Weighted and Fluid-Attenuated Inversion Recovery Findings, and Correlation with Plasma Ammonia Level and Clinical Outcome • A.M. McKinney, B.D. Lohman, B. Sarikaya, E. Uhlmann, J. Spanbauer, T. Singewald, and J.R. Brace
In acute hepatic encephalopathy, MR imaging abnormalities have been described in the white matter, thalami, and corticospinal tracts. These authors sought to determine characteristic regions of involvement on fluid-attenuated inversion recovery and diffusion-weighted imaging to evaluate their reversibility, and to correlate MR imaging extent with clinical severity. Less than 21 days after onset of symptoms, MR (with FLAIR and DWI) studies were obtained in 20 patients. DWI and FLAIR similarly demonstrated the abnormalities in the thalami, white matter, and cortex. The authors concluded that patients with acute hepatic encephalopathy exhibit characteristic regions of involvement on FLAIR with DWI findings that can be reversible. The MR imaging extent on FLAIR and DWI strongly correlates with the maximal plasma ammonia levels, which also correlate well with outcome. Diffuse cortical involvement had a higher potential for neurologic sequelae but could be reversible.

Emergent Self-Expanding Stent Placement for Acute Intracranial or Extracranial Internal Carotid Artery Dissection with Significant Hemodynamic Insufficiency • P. Jeon, B.M. Kim, D.I. Kim, Y.S. Shin, K.H. Kim, S.I. Park, D.J. Kim, and S.H. Suh
Patients with internal carotid artery dissections and hemodynamic insufficiency have a progressive and/or fulminant course. Here, the authors stented the extra- or intracranial ICA in such situations. Eight patients with dissections and hemodynamic insufficiency underwent emergency stenting. Abnormal perfusion was documented in all by CT or MR imaging and catheter angiography showed findings ranging from occlusion to critical stenoses. Stent placement was successful in all and no complications occurred. Neurologic symptoms resolved in a matter of days and all were asymptomatic at an average follow-up of 21 months. Angiographic follow-up in 6 patients showed no residual or in-stent stenoses. Conclusion: self-expanding stent placement is a safe and effective option for selected patients with significant hemodynamic insufficiency due to acute intracranial or extracranial ICA dissections.

BONUS: Cumulative Radiation Dose during Hospitalization for Aneurysmal Subarachnoid Hemorrhage • S.I. Moskowitz, W.J. Davros, M.E. Kelly, D. Fiorella, P.A. Rasmussen, and T.J. Masaryk
More on radiation exposure…. Patients with ruptured aneurysms generally undergo a multitude of studies (CT, CTA, angiograms) during their hospitalization. Here, a cohort of 50 such patients was studied and, in particular, the potential for short-term skin injury and long-term tumor risk was assessed. The authors demonstrated that substantial cumulative doses can be seen, with 87% of the cumulative absorbed dose occurring during neurointerventional procedures and 7% from CT. The authors concluded that repetitive irradiation during the care of patients with aneurysmal subarachnoid hemorrhage can result in significant cumulative doses and a variety of techniques can be applied to reduce this absorbed dose. Use of radiation for diagnostic and therapeutic purposes during prolonged procedures in patients with subarachnoid hemorrhage demands diligence throughout hospitalization.

Fellows’ Journal Club

Brain Abnormalities on MR Imaging in Patients with Retinoblastoma • F. Rodjan, P. de Graaf, A.C. Moll, S.M. Imhof, J.I.M.L. Verbeke, E. Sanchez, and J.A. Castelijns
The authors retrospectively studied brain MR images in 168 patients with retinoblastoma collected during a 20-year period. They looked for tumors, structural abnormalities, myelinization, and other findings. Clinically, they reviewed for laterality of disease, heredity, and chromosomal (13q deletion) abnormalities. Ninety patients had hereditary disease, 7 showed the 13q mutation, 5 had pineoblastomas, and 9 pineal cysts. Two patients with 13q deletion each had callosal agenesis and the Dandy-Walker variant. The authors concluded that pineoblastoma and structural brain anomalies are seen only in those with hereditary disease and 13q deletion whereas the incidence of pineal cysts is similar to that of the general population.

Percutaneous Vertebroplasty Is Not a Risk Factor for New Osteoporotic Compression Fractures: Results from VERTOS II • C.A.J. Klazen, A. Venmans, J. de Vries, W.J. van Rooij, F.H. Jansen, M.C. Blonk, P.N.M. Lohle, J.R. Juttmann, E. Buskens, K.J. van Everdingen, A. Muller, H. Fransen, O.E. Elgersma, W.P.Th.M. Mali, and H.J.J. Verhaar
VERTOS: percutaneous vertebroplasty versus conservative therapy. There is some evidence that PV increases the risk of new fractures in vertebrae above or below a treated level. Here, the authors randomized 202 patients to either PV or conservative treatment and followed them for an average of 1 year with spine radiographs, looking for new fractures. Eighteen new fractures were found in 15 of 91 PV patients and 30 new fractures in 21 of 85 patients who had conservative therapy. The only risk factor was the number of vertebral fractures present at baseline. The authors concluded that the incidence of new fractures after PV is not significantly different from that found in conservatively treated patients.

Percutaneous Vertebroplasty and Pulmonary Cement Embolism: Results from VERTOS II • A. Venmans, C.A.H. Klazen, P.N.M. Lohle, W.J. van Rooij, H.J.J. Verhaar, J. de Vries, and W.P.Th.M. Mali
The same authors as above used data collected during the same trial and here report the incidence of pulmonary cement embolism after PV. From a group of 202 patients, 78 received PV and a CT scan of the chest was done in 54 of them. Risk factors such as age, gender, number of treated vertebrae, and cement volumes and leakages were assessed. Pulmonary embolism was detected in 14 of 54 patients; all were asymptomatic and emboli were small and randomly distributed. With time, no inflammatory response was documented. Conclusion: routine post-PV chest CT is not needed, and if pulmonary emboli occur they tend to be small and clinically silent.

BONUS: Maintenance of Certification: Update on Attitudes of Members of the American Society of Neuroradiology • D.M. Yousem and A. Nidecker
All current and future fellowship graduates will have to submit to the Maintenance of Certification process that includes the infamous Practice Quality Improvement among other requirements. These authors sent out a 12-question survey to 2863 ASNR members regarding this issue. Slightly more than 80% of responders were aware of the continuing medical education, self-assessment module, and test requirements for recertification. Sixty-five percent had not started a PQI project and all felt ASNR should help significantly in completing the requirements. Open comments were generally unfavorable toward the MOC-PQI process by a 3:1 ratio. Conclusion: compliance with the MOC process has improved since a prior survey 3 years ago, however, confusion over the PQI process remains the primary concern of ASNR members. For more on this important topic, please read the Commentary by Dr. Robert Zimmerman on this same issue and listen to this month’s podcast.