C.G. Choi

Intracranial Stenting of Severe Symptomatic Intracranial Stenosis: Results of 100 Consecutive Patients

BACKGROUND AND PURPOSE: There are a few reports regarding the outcome evaluation of balloon-expandable intracranial stent placement (BEICS). The purpose of our study was to evaluate the outcome and factors related to the adverse events (AEs) of BEICS. MATERIALS AND METHODS: We evaluated 100 consecutive patients who underwent BEICS. We assessed the procedural success (residual stenosis <50%), AEs (minor strokes, major strokes, and death), clinical outcome, and restenosis (>50%) at 6 months. We also analyzed 18 factors including symptom patterns related to AE rate. Symptom patterns revealed 1) stable patients (n = 73) with improving, stationary, or resolved symptoms; and 2) unstable patients (n = 27) with gradual worsening or fluctuating symptoms (National Institutes of Health Stroke Scale [NIHSS] ≥4) within 2 days before stent placement. RESULTS: The procedural success rate was 99%. Overall, there were 10 (10%) AEs within the 6 months: 4 (4%) minor strokes, 3 (3%) major strokes, and 3 (3%) deaths including a death from myocardial infarction. AE rate was 4.1% in stable and 25.9% in unstable patients. Restenosis at 6 months revealed 0% (0/59). Good outcome (modified Rankin Scale ≤2) at 6 months was 97% (71/73) in stable and 67% (18/27) in unstable patients. Stepwise logistic regression model revealed that symptom pattern (unstable versus stable) was the only significant risk factor (OR, 8.167; 95% CI, 1.933–34.500; P = .004). CONCLUSION: BEICS revealed a low AE and good outcome rate at 6 months, especially in the stable patients. Midterm outcome was also favorable in the unstable patient group.

Histogram Analysis of Intravoxel Incoherent Motion for Differentiating Recurrent Tumor from Treatment Effect in Patients with Glioblastoma: Initial Clinical Experience

BACKGROUND AND PURPOSE: Intravoxel incoherent motion can simultaneously measure diffusion and perfusion characteristics. Our aim was to determine whether the perfusion and diffusion parameters derived from intravoxel incoherent motion could act as imaging biomarkers for distinguishing recurrent tumor from treatment effect in patients with glioblastoma. MATERIALS AND METHODS: Fifty-one patients with pathologically confirmed recurrent tumor (n = 31) or treatment effect (n = 20) were assessed by means of intravoxel incoherent motion MR imaging. The histogram cutoffs of the 90th percentiles for perfusion and normalized CBV and the 10th percentiles for diffusion and ADC were calculated and correlated with the final pathology results. A leave-one-out cross-validation was used to evaluate the diagnostic performance of our classifiers. RESULTS: The mean 90th percentile for perfusion was significantly higher in the recurrent tumor group (0.084 ± 0.020) than in the treatment effect group (0.040 ± 0.010) (P < .001). The 90th percentile for perfusion provided a smaller number of patients within an overlap zone in which misclassifications can occur, compared with the 90th percentile for normalized CBV. The mean 10th percentile for diffusion was significantly lower in the recurrent tumor group than in the treatment effect group (P = .006). Receiver operating characteristic curve analyses showed the 90th percentile for perfusion to be a significant predictor for differentiation, with a sensitivity of 87.1% and a specificity of 95.0%. There was a significant positive correlation between the 90th percentiles for perfusion and normalized CBV (r = 0.674; P < .001). CONCLUSIONS: A histogram analysis of intravoxel incoherent motion parameters can be used as a noninvasive imaging biomarker for differentiating recurrent tumor from treatment effect in patients with glioblastoma.

Placement of Covered Stents for Carotid Blowout in Patients with Head and Neck Cancer: Follow-up Results after Rescue Treatments

BACKGROUND AND PURPOSE: Placement of a covered stent to control carotid blowout (CB) in malignant tumors of the head and neck has been reported to be an effective treatment. However, it is not uncommon to encounter recurrent hemorrhage. The purpose of this study was to evaluate the follow-up results of patients treated with covered stents. MATERIALS AND METHODS: We retrospectively reviewed the results of 7 consecutive patients who underwent placement of a covered stent to control CB. Most of them had poor wound healing because of previous irradiation, surgery, or both. The initial procedures were successful in all patients. Their clinical course was reviewed for rebleeding, additional endovascular treatments in recurrent cases, and outcomes. RESULTS: Recurrence developed in 6 of 7 patients. The interval between the first procedure and the hemorrhagic event was from 3 to 44 days. In 6 patients who had a recurrent CB, 4 had rebleeding from the previous site of the stent, whereas 2 other patients experienced recurrent bleeding in a different area from the site of the stent. Additional endovascular treatments were carried out in all affected patients by another insertion of a covered stent (n = 3), coil embolization (n = 2), or insertion of a covered stent followed by permanent arterial occlusion (n = 1). CONCLUSION: Placement of a covered stent in patients with head and neck cancer who sustain CB showed frequent rebleeding despite favorable initial rescue results. Recurrent CB at the previous stent site developed frequently in patients with uncontrolled wound infection. Concomitant or short-interval arterial trapping should be considered selectively in those conditions.

Detection of CSF Leak in Spinal CSF Leak Syndrome Using MR Myelography: Correlation with Radioisotope Cisternography

BACKGROUND AND PURPOSE: Spinal CSF leak syndrome is a unique disorder caused by spinal CSF leak. In this study, we attempted to determine whether MR myelography (MRM) can detect the leakage site in the spine. MATERIALS AND METHODS: We performed both MRM and radioisotope cisternography (RIC) in 15 patients with spinal CSF leak syndrome. Patients were included in this study if they had at least 2 of the following criteria: 1) orthostatic headache, 2) low CSF opening pressure, and 3) diffuse pachymeningeal enhancement on brain MR imaging. For comparison, we performed MRM in 15 subjects without symptoms of spinal CSF leak syndrome. MRM was performed with the 2D turbo spin-echo technique in the entire spine by using a 1.5T scanner. Two blinded radiologists evaluated the MRM findings in a total of 30 cases, composed of patient and control groups, with regard to the presence of leakage and the level of leakage if present. RIC was performed only in the patient group and was assessed by consensus among 3 physicians experienced in nuclear medicine. The diagnostic performance of MRM and RIC was evaluated on the basis of the clinical diagnosis of spinal CSF leak syndrome. RESULTS: The sensitivity, specificity, and accuracy of MR myelography for detecting CSF leak was 86.7%, 86.7%, and 86.7% for reader 1, respectively, and 80.0%, 93.3%, and 86.7% for reader 2, respectively. The sensitivity of RIC was 93.3%. Agreement between the 2 techniques for the detection of CSF leak was substantial in reader 1 and moderate in reader 2 (κ = 0.634 and 0.444, respectively). CONCLUSION: MRM is an effective tool for detecting CSF leak in the spine in patients with spinal CSF leak syndrome.

Dual-Energy CT in the Evaluation of Intracerebral Hemorrhage of Unknown Origin: Differentiation between Tumor Bleeding and Pure Hemorrhage

BACKGROUND AND PURPOSE: Detection of underlying tumor in patients with unknown-origin acute ICH may be difficult because acute hematoma may mask enhancement of tumor on postcontrast CT. We intended to investigate the clinical utility of DECT in differentiating tumor bleeding from pure ICH. MATERIALS AND METHODS: Using a dual-source CT scanner, we obtained TNC single-energy and postcontrast DECT scans for 56 patients with unknown-origin spontaneous ICH. From the 2 sets of postcontrast DECT images obtained with different tube energy, EA (equivalent to conventional postcontrast CT), VNC, color-coded iodine overlay, fusion images of iodine overlay and VNC images were produced. The diagnostic performances of fusion, EA, and combined EA and TNC images for detecting underlying tumors were compared. RESULTS: Of the 56 patients, 17 had primary or metastatic tumors (18 lesions) and 39 had nontumorous ICH. The sensitivities of fusion, EA, and combined EA and TNC images for detecting brain tumors were 94.4%, 61.1%, and 66.7%, respectively, and their specificities were 97.4%, 92.3%, and 89.7%, respectively. The areas under the ROC curves were 0.964, 0.786, and 0.842, respectively. Overall, the diagnostic performance of fusion images was significantly superior to EA (P = .006) and combined EA and TNC (P = .011) images. CONCLUSIONS: DECT may be useful in detecting underlying tumors in patients with unknown-origin ICH.

Prognostic Factors for Neurologic Outcome after Endovascular Revascularization of Acute Symptomatic Occlusion of the Internal Carotid Artery

BACKGROUND AND PURPOSE: Management of acute symptomatic internal carotid artery (ICA) occlusion remains controversial. We evaluated outcome predictors of a good recovery in patients with acute symptomatic ICA occlusion. MATERIALS AND METHODS: We retrospectively evaluated 33 consecutive patients (men/women, 23/10; mean age, 66 years) with: 1) acute symptomatic ICA occlusion within 6 hours of symptom onset or with mismatch of symptoms and an early infarct area, 2) National Institutes of Health Stroke Scale (NIHSS) score of 6 or more, and 3) attempted endovascular revascularization of the occluded ICA. Various single and multiple variable analyses were conducted to assess the association of 14 predictors with short-term (1-month NIHSS) and long-term (1-year modified Rankin Scale [mRS]) outcomes. RESULTS: Successful recanalization (at or more than grade 2 distal residual occlusion) was obtained in 14 (42%) of 33 and good recovery (mRS ≤2) after 1 year in 11 (33%) of 33. Distal residual occlusion (DRO; P = .005), initial NIHSS score (P = .023), and postprocedural thrombolysis in cerebral infarction (P = .027), retrograde ICA filling (P = .036), and ophthalmic collaterals (P = .046) were significant predictors of short-term outcome. DRO (P = .018) and initial NIHSS (P = .033) were significant predictors of long-term outcome on univariable analysis. DRO was the only significant predictor for short-term (P = .026) and long-term outcome (P = .033) on multivariable logistic regression. CONCLUSIONS: Active revascularization of acute symptomatic ICA occlusion resulted in good recovery in one third of patients after 1 year. DRO is an independent predictor of a favorable clinical outcome.

Cerebral Fat Embolism: Diffusion-weighted Magnetic Resonance Imaging Findings

Purpose: To demonstrate the diffusion-weighted (DWI) magnetic resonance imaging (MRI) findings, and the follow-up MRI findings, of cerebral fat embolism in the acute stage. Material and Methods: The initial DWI and clinical findings of six patients with cerebral fat embolism were retrospectively evaluated. The finding of DWI with a b-value of 1000 s/mm2 (b = 1000) was compared with that of DWI with a b-value of 0 s/mm2 (b = 0). In three patients who underwent follow-up MRI, the interval change of the lesion on T2-weighted images was investigated. Results: The characteristic DWI finding of cerebral fat embolism in the acute stage was multiple, hyperintense, dot-like lesions disseminated in the brain. These lesions were distributed dominantly in the bilateral border-zone areas. Some lesions had an ancillary location including the cortex, deep white matter, basal ganglia, and cerebellum. The lesions were more intense and numerous in DWI (b = 1000) than in DWI (b = 0). The findings on the follow-up T2-weighted images were multiple confluent hyperintense lesions in the white matter with progression since the initial MRI. Conclusion: DWI could be a sensitive tool for detecting cerebral fat embolism in the acute phase. It is recommended that DWI be included in the initial evaluation of cerebral fat embolism with MRI.

Utility of Intravoxel Incoherent Motion MR Imaging for Distinguishing Recurrent Metastatic Tumor from Treatment Effect following Gamma Knife Radiosurgery: Initial Experience

BACKGROUND AND PURPOSE: Intravoxel incoherent motion MR imaging can simultaneously measure the diffusion and perfusion characteristics of brain tumors. Our aim was to determine the utility of intravoxel incoherent motion–derived perfusion and diffusion parameters for assessing the treatment response of metastatic brain tumor following gamma knife radiosurgery. MATERIALS AND METHODS: Ninety-one consecutive patients with metastatic brain tumor treated with gamma knife radiosurgery were assessed by using intravoxel incoherent motion imaging. Two readers independently calculated the 90th percentile and the 10th percentile histogram cutoffs for perfusion, normalized CBV, diffusion, and ADC. Areas under the receiver operating characteristic curve and interreader agreement were assessed. RESULTS: With the combination of the 90th percentile histogram cutoff for perfusion and the 10th percentile histogram cutoff for diffusion, the sensitivity and specificity for differentiating recurrent tumor and treatment were 79.5% and 92.3% for reader 1 and 84.6% and 94.2% for reader 2, respectively. With the combination of the 90th percentile histogram cutoff for normalized CBV and the 10th percentile histogram cutoff for ADC, the sensitivity and specificity for differentiating recurrent tumor and treatment were 69.2% and 100.0% for reader 1 and 74.3% and 100.0% for reader 2, respectively. Compared with the combination of 90th percentile histogram cutoff for normalized CBV and the 10th percentile histogram cutoff for ADC, adding intravoxel incoherent motion to 90th percentile histogram cutoff for normalized CBV substantially improved the diagnostic accuracy for differentiating recurrent tumor and treatment from 86.8% to 92.3% for reader 1 and from 89.0% to 93.4% for reader 2, respectively. The intraclass correlation coefficients between readers were higher for perfusion parameters (intraclass correlation coefficient range, 0.84–0.89) than for diffusion parameters (intraclass correlation coefficient range, 0.68–0.79). CONCLUSIONS: Following gamma knife radiosurgery, intravoxel incoherent motion MR imaging can be used as a noninvasive imaging biomarker for differentiating recurrent tumor from treatment effect in patients with metastatic brain tumor.

MR Diagnosis of Facial Neuritis: Diagnostic Performance of Contrast-Enhanced 3D-FLAIR Technique Compared with Contrast-Enhanced 3D-T1-Fast-Field Echo with Fat Suppression

BACKGROUND AND PURPOSE: Current MRI with the CE T1-weighted sequence plays a limited role in the evaluation of facial neuritis due to prominent normal facial nerve enhancement. Our purpose was to retrospectively investigate the usefulness of the CE 3D-FLAIR sequence compared with the CE 3D-T1-FFE sequence in facial neuritis patients. MATERIALS AND METHODS: We assessed 36 consecutive patients who underwent temporal bone MR imaging at 3T for idiopathic facial palsy. Two readers independently reviewed CE 3D-T1-FFE and CE 3D-FLAIR images to determine the degree of enhancement in each of 5 segments of the facial nerve. We compared AUCs using the Z-test, compared diagnostic performance of 2 MR techniques with the McNemar test, and evaluated interobserver agreement. The Pearson χ2 test was used for each segment of the facial nerve. RESULTS: The AUC of CE 3D-FLAIR (reader 1, 0.754; reader 2, 0.746) was greater than that of CE 3D-T1-FFE (reader 1, 0.624; reader 2, 0.640; P < .001). The diagnostic sensitivities, specificities, and accuracies were 97.2%, 86.1%, and 91.7%, respectively, for CE 3D-FLAIR, and 100%, 56.9%, and 78.5%, respectively, for CE 3D-T1-FFE. The specificity and accuracy of CE 3D-FLAIR were greater than those of CE 3D-T1-FFE (specificity, P = .029; accuracy, P = .008). The interobserver agreements for CE 3D-FLAIR (κ-value, 0.831) and CE 3D-T1-FFE (κ-value, 0.694) were excellent. Enhancement of the canalicular and anterior genu segments on CE 3D-FLAIR were significantly correlated with the occurrence of facial neuritis (P < .001 for canalicular; P = .032 and 0.020 for anterior genu by reader 1 and reader 2, respectively). CONCLUSIONS: CE 3D-FLAIR can improve the specificity and overall accuracy of MR imaging in patients with idiopathic facial palsy.

Internal carotid artery stenosis with ipsilateral persistent hypoglossal artery presenting as a multiterritorial embolic infarction: a case report

Persistent hypoglossal artery (PHA) is a relatively rare vascular anomaly of persistent carotid-basilar anastomosis. We have treated a patient with stenosis of the internal carotid artery which was combined with PHA and who presented with multiple small embolic infarcts in multiple vascular territories. It is important to know that a persistent carotid-basilar anastomosis could be one of the causes bringing about acute infarction in both the anterior and posterior vascular territories, mimicking cardioembolism.