Accuracy of the detection of infratentorial stroke lesions using perfusion CT: an experimenter-blinded study.

INTRODUCTION: Although perfusion CT (PCT) for the detection of supratentorial stroke is well established, there is a dearth of evidence of its effectiveness in the detection of infratentorial stroke. Hence, this study compared sensitivity, specificity, and accuracy of PCT maps between infratentorial and supratentorial stroke lesions. METHODS: One hundred patients with acute stroke who had successfully undergone near whole-brain PCT with the toggling table technique and follow-up MRI were included. Wilcoxon Mann-Whitney test was performed at P<0.01. RESULTS: There was no significant statistical difference in the accuracy (91.79% vs. 93.23% in regional cerebral blood volume; 92.26% vs. 95.31% in regional cerebral blood flow; 89.17% vs. 92.71% in mean transit time; 89.76% vs. 92.19% in time to peak; P>0.01 in all PCT maps) between supratentorial and infratentorial stroke. Also, there was no remarkable difference in both sensitivity and specificity of PCT maps. CONCLUSION: This was the first study to investigate the accuracy of PCT with the toggling table technique in detection of infratentorial stroke lesions. Clinically, PCT is highly reliable and accurate in detecting infratentorial stroke lesions.

Occlusion of traumatic carotid cavernous fistula by incidentally formed thrombus during the interventional procedure: a case report.

In this report, we present a rare case of traumatic carotid cavernous fistula that was occluded during the interventional procedure by incidentally formed blood clot. Sudden occlusion of the fistula and the resolution process of the precarious blood clot can be clearly seen on the serial angiogram.

Body size effect on brain volume in Korean youth.

The relationship between human body size and brain size is still controversial, although brain size increases with body size across taxonomic levels. The magnetic resonance imaging volumetric analysis of the brain was performed in healthy 20-year old Koreans to investigate the effect of body size on brain volume. The whole brain volume was significantly correlated with body height in male (r=0.37, P<0.05) but not in female participants. The height effect on whole brain volume was increased considerably when data from both male and female participants were combined (r=0.57, P<0.05). The cerebellum volume was moderately correlated with body height in female (r=0.43, P<0.05) but not in male participants. The difference between sexes of the effect of body size on the brain needs to be investigated further.

The meaning of the prognostic factors in ruptured middle cerebral artery aneurysm with intracerebral hemorrhage.

OBJECTIVE: This study analyzed the relationship between prognosis and multiple clinical factors of ruptured middle cerebral artery (MCA) aneurysm with intracerebral hemorrhage (ICH), to aid in predicting the results of surgical treatment. METHODS: Enrolled subjects were 41 patients with ruptured MCA aneurysm with ICH who were treated with surgical clipping. Clinical factors such as gender, age, and initial Glasgow coma scale were assessed while radiological factors such as the volume and location of hematoma, the degree of a midline shift, and aneurysm size were considered retrospectively. Prognosis was evaluated postoperatively by Glasgow outcome scale. RESULTS: Age and prognosis were correlated only in the groups with ICH over 31 mL or ICH at the frontal lobe or sylvian fissure. When initial mental status was good, only patients with ICH on the temporal lobe had a better prognosis. If the midline shift was less than 4.5 mm, the probability of better prognosis was 95.5% (21 of 22). If the midline shift was more than 4.5 mm, the probability of poor prognosis was 42.1% (8 of 19). Patients with ICH less than 31 mL had higher survival rates, whereas if the ICH was more than 31 mL, 41.2% (7 of 17) had a poor clinical pathway. CONCLUSION: Even if the initial clinical condition of the patient was not promising, by carefully examining and taking into account all factors, neurosurgeons can confidently recommend surgical treatment for these patients.

Dynamic CT perfusion imaging for the detection of crossed cerebellar diaschisis in acute ischemic stroke.

OBJECTIVE: Although the detection of crossed cerebellar diaschisis (CCD) by means of different imaging modalities is well described, little is known about its diagnosis by computed tomography perfusion (CTP) imaging. We investigated the detection rate of CCD by CTP imaging and the factors related to CCD on CTP images in patients with acute ischemic stroke. MATERIALS AND METHODS: CT perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time-to-peak (TTP) obtained from 81 consecutive patients affected by an acute ischemic stroke were retrospectively reviewed. Whole-brain perfusion maps were obtained with a multichannel CT scanner using the toggling-table technique. The criteria for CCD was a unilateral supratentorial ischemic lesion and an accompanying decrease in perfusion of the contralateral cerebellar hemisphere on the basis of CTP maps by visual inspection without a set threshold. Maps were quantitatively analyzed in CCD positive cases. RESULTS: The criteria for CCD were fulfilled in 25 of the 81 cases (31%). Detection rates per CTP map were as follows: MTT (31%) > TTP (21%) > CBF (9%) > CBV (6%). Supratentorial ischemic volume, degree of perfusion reduction, and infratentorial asymmetry index correlated strongly (R, 0.555-0.870) and significantly (p < 0.05) with each other in CCD-positive cases. CONCLUSION: It is possible to detect CCD on all four of the CTP-based maps. Of these maps, MTT is most sensitive in detecting CCD. Our data indicate that CTP imaging is a valid tool for the diagnosis of CCD in patients affected by an acute hemispheric stroke.

Endovascular Embolization of Intracranial Aneurysms Using Bare Platinum Axium™ Detachable Coils: Immediate and Short-Term Follow-up Results from a Multicenter Registry.

PURPOSE: Axium™ coils were developed to improve the durability of coil-embolized cerebral aneurysms by increasing packing density. The purpose of this prospective multicenter registry was to evaluate the safety and durability of Axium™ coils. MATERIALS AND METHODS: One hundred twenty-six patients with 135 aneurysms of ≤ 15 mm in size underwent coil embolization using bare platinum coils, with Axium™ coils constituting over 50% of the total coil length. Immediate and short-term follow-up results were prospectively registered and retrospectively evaluated. RESULTS: Of the 135 aneurysms (83 unruptured and 52 ruptured), immediate post-embolization angiography revealed complete occlusion in 80 aneurysms (59.3%), neck remnants in 47 (34.8%), and incomplete occlusion in 8 (5.9%). The mean packing density was 42.8% (range, 9.5 - 90%) with Axium™ coil length constituting a mean of 87.9% of total coil length. The rate of procedure-related complications was 16.3%. Procedure-related permanent morbidity and mortality rates were 3.2% and 0.8%, respectively. Follow-up catheter or MR angiography, which was available in 101 aneurysms at 6 - 15 months (mean, 7.7 months), revealed stable or improved occlusion in 95 aneurysms and worsening in 6 aneurysms (5.9%). Lower packing density (< 30%) remained the only predictor for anatomical worsening on multivariable logistic regression analysis (P < 0.05). CONCLUSION: In this registry, Axium™ coils showed a relatively low rate of anatomical worsening on short-term follow-up imaging with an acceptable periprocedural safety profile compared to reports of other platinum coils. These results may warrant further study of long-term durability with Axium™ coils in larger populations.

Guidewire breakage during neurointerventional procedures: a report of two cases.

We report on two cases of microguidewire breakage that occurred during endovascular treatment of intracranial aneurysms. The microguidewire can be broken when a part of the wire is stuck due to vascular tortuosity, and, subsequently, application of excessive rotational movement. The mechanical and physical properties of a microguidewire are also important factors in microguidewire breakage. We also suggest technical tips for avoidance of this problem.

Lung perfusion CT: the differentiation of cavitary mass.

PURPOSE: To assess the findings of perfusion maps and to evaluate the usefulness of perfusion computed tomography (CT) in the differentiation of cavitary mass. MATERIALS AND METHODS: Fifty-three patients with cavitary lung masses were analyzed. Dynamic chest CT was performed after contrast injection. The volume map, washout map, peak map, and time-to-peak (TTP) map were reformatted using Interactive Data Language (IDL). The perfusion patterns were classified into three scoring groups, and these scorings were repeated after 2-week intervals. Diagnostic confidence levels were assigned by consensus. The kappa statistics was used to determine intraobserver agreement, and Fisher's exact test was used to analyze statistical differences in perfusion scores. Receiver operating characteristic (ROC) analysis was performed to evaluate the usefulness of the perfusion maps. RESULTS: Perfusion maps were reformatted pixel-by-pixel from the time-to-density curve analyses. Pyogenic cavities showed weak washout and slow TTP (69.6%). Conversely, malignant cavities showed strong washout (73.3%). Tuberculous cavities showed low perfusions in the volume and peak maps (66.7%). Intraobserver agreement was excellent. The performance of the combination of CT and perfusion maps was better than that of CT alone. CONCLUSION: Lung perfusion CT could be a promising and feasible method for differentiation of cavitary mass.

Simple oblique lumbar magnetic resonance imaging technique and its diagnostic value for extraforaminal disc herniation.

STUDY DESIGN: Prospective study evaluating the oblique lumbar magnetic resonance imaging (MRI). OBJECTIVE: To present the technique of oblique lumbar MRI and assess the clinical efficacy of this technique for diagnosis of extraforaminal disc herniation. SUMMARY OF BACKGROUND DATA: Herniated lumbar discs are traditionally diagnosed using conventional lumbar axial and sagittal MRI. However, conventional lumbar MRI might not reveal nerve root compression in the extraforaminal area. Oblique lumbar MRI can provide clear visualization of the dorsal root ganglion and lumbar nerve root in the foraminal and extraforaminal areas. METHODS: Ten patients diagnosed with extraforaminal disc herniations underwent bilateral oblique lumbar MRIs before surgery (turbo spin-echo T2-weighted sequence). We compared the side with symptomatic extraforaminal disc herniation to the asymptomatic contralateral side. RESULTS: Oblique lumbar MRI succeeded in depicting pedicles, dorsal root ganglions, and lumbar nerve roots of the foraminal and extraforaminal areas. In 9 of 10 patients (90.0%), nerve root compression by the herniated disc in the extraforaminal area was clearly demonstrated when compared with the asymptomatic contralateral side (P < 0.05). In 1 patient with scoliosis and spinal stenosis, oblique MRI could not clearly display foraminal or extraforaminal anatomy due to spinal deformity. CONCLUSION: In light of this data, we suggest that oblique lumbar MRI can precisely demonstrate nerve roots in foraminal and extraforaminal areas. This technique is a simple and useful diagnostic tool for extraforaminal lumbar disc herniations.

Prediction of clinical outcome with baseline and 24-hour perfusion CT in acute middle cerebral artery territory ischemic stroke treated with intravenous recanalization therapy.

INTRODUCTION: We sought to determine whether Alberta Stroke Program Early CT Scores (ASPECTS) derived from baseline noncontrast CT (NCCT) and perfusion CT (CTP) imaging maps can predict clinical outcome after recanalization therapy in acute ischemic stroke of the middle cerebral artery (MCA) territory and whether changes in the ASPECTS from baseline to 24 h after recanalization therapy can help predict clinical outcome. METHODS: We retrospectively studied consecutive patients with acute ischemic stroke of the MCA territory treated with intravenous tissue plasminogen activator (t-PA) or abciximab within 6 h of symptom onset. We performed NCCT and CTP before and 24 h after intravenous t-PA or abciximab treatment and determined the ASPECTS and the changes in the ASPECTS from baseline to 24 h. A favorable outcome was defined as a modified Rankin scale score of 0 or 1 at 3 months. RESULTS: During the 18-month study period 44 patients were studied. In multivariate logistic regression analysis, the cerebral blood volume (CBV) ASPECTS (OR 1.80, 95% CI 1.10 to 2.93) at baseline and the increase in cerebral blood flow (CBF) ASPECTS (OR 1.68, 95% CI 1.13 to 2.50) from baseline to 24 h were associated with a favorable outcome. The cutoff values for a favorable outcome using receiver operating characteristic curves were 8 and 1, respectively. When the CBV ASPECTS at baseline was 8 or more, its positive predictive value was only 58.1%. When the CBV ASPECTS at baseline was 8 or more and the increase in CBF ASPECTS from baseline to 24 h was 1 or more, the positive predictive value was 100% and the negative predictive value was 74.2%. CONCLUSION: The CBV ASPECTS derived from baseline CTP maps was found to be predictive of a favorable outcome, but its positive predictive value was suboptimal. The change in the CBF ASPECTS from baseline to 24 h after treatment was helpful in predicting outcome.

Accuracy of transcranial Doppler sonography for predicting cerebral infarction in aneurysmal subarachnoid hemorrhage.

PURPOSE: To evaluate the accuracy of transcranial Doppler (TCD) sonography using different criteria for predicting cerebral infarction due to symptomatic vasospasm. METHODS: We retrospectively evaluated the clinical and radiologic data of consecutive patients admitted with acute aneurysmal subarachnoid hemorrhage (SAH) in the anterior cerebral circulation between January 2001 and June 2002. TCD sonographic examinations were performed on alternate days up to 20 days after admission. Cerebral infarction was defined on CT as a new hypodensity in the vascular distribution with corresponding clinical symptoms. Vasospasm was diagnosed as mild or severe when TCD sonography revealed a mean blood flow velocity (MBFV) greater than 120 and 180 cm/s in the middle or anterior cerebral artery and in the intracranial part of the internal carotid artery, respectively. RESULTS: A total of 93 patients with aneurysmal SAH in the anterior cerebral circulation were included. Vasospasm was demonstrated by TCD sonography in 60 patients (64.5%) and was shown via multivariable logistic regression analysis to be predictive of cerebral infarction (OR 3.11, 95% CI 1.46-6.59), with an 82.6% and 69.6% sensitivity, a 41.4% and 77.1% specificity, a 31.7% and 50.0% positive predictive value, and an 87.9% and 88.5% negative predictive value when the MBFV was greater than 120 and 180 cm/s, respectively. CONCLUSIONS: Vasospasm on TCD was found to be predictive of symptomatic cerebral infarction on CT, but its positive predictive value remained low despite the adoption of restrictive TCD criteria for vasospasm.