Feasibility of high-resolution MR imaging for the diagnosis of intracranial vertebrobasilar artery dissection.

OBJECTIVES: To evaluate the feasibility of high-resolution MRI (HR-MRI) for diagnosing intracranial vertebrobasilar artery dissection (VBD) and to identify the most useful imaging findings suggesting dissection. METHODS: We retrospectively reviewed 50 patients with suspected intracranial VBDs who underwent HR-MRI. Two neuroradiologists independently reviewed the HR-MR images. The diagnosis based on HR-MRI was compared with the final diagnosis by consensus among the neuroradiologists, neurointerventionist, and neurologist. Two neuroradiologists also sought signs of dissection (mural hematoma, dissection flap, outer-diameter enlargement on T2WI of steno-occlusive lesions). Inter- and intraobserver agreements were analysed. RESULTS: HR-MRI corroborated the final diagnosis in 47 (94%; 31 VBD and 16 non-VBD) patients. A mural haematoma was best detected on T1WI and contrast-enhanced (CE)-T1WI (54.3%). Dissection flaps were observed in almost all cases on CE-T1WI (91.4 %), and then were detected on T2WI (68.6%). Outer-diameter enlargement of the steno-occlusive lesions on angiography was detected in more than half of the cases (62.9%). The two reviewers showed almost perfect agreement for the diagnosis of VBD and detecting dissection signs on every sequence. CONCLUSIONS: HR-MRI can be a useful and non-invasive diagnostic tool for intracranial VBD, and dissection flaps on CE-T1WI are the signs with the greatest diagnostic value. KEY POINTS: Direct imaging findings of dissection were well visualised by HR-MRI. Detection of a dissection flap on CE-T1WI is the most reliable diagnostic finding. HR-MRI could be a useful diagnostic tool for intracranial VBDs.

Comparison of arthroscopic and magnetic resonance imaging findings in osteochondral lesions of the talus.

BACKGROUND: Magnetic resonance imaging (MRI) is widely used for diagnosing osteochondral lesions in the talus. The purpose of this study was to directly compare the MRI with the arthroscopic findings. MATERIALS AND METHODS: MR images of 42 ankles were retrospectively reviewed during a period of 67 months. The osteochondral lesions were evaluated by both MRI (0, normal; 1, subchondral trabecular compression and marrow edema; 2A, subchondral cyst; 2B incomplete separation fragment; 3, unattached, nondisplaced fragment with synovial fluid surrounding it; 4, displaced fragment) and arthroscopy (A, smooth and intact, but soft and ballottable cartilage; B, rough surfaces; C, fibrillations or fissures; D, flap present or bone exposed; E, loose, undisplaced fragment; F, displaced fragment). Arthroscopic grade A was considered to be equivalent to MR grade 1, B and C to MR grade 2A, D to 2B, E to 3, and F to 4. RESULTS: Of the 44 lesions in 42 ankles, 29 lesions marked the same grade on both MRI and arthroscopy (65.9%). Nine lesions were upgraded on arthroscopy (20.5%), and six were downgraded (13.6%). MR grade 3 lesions showed the best correlation (83.3%) and MR grade 1 and 2B lesions showed the worst (50.0 and 55.6 %). Arthroscopic grade A and F showed good correlation (80 and 100%). Grade C and E showed poor (25.0%) and intermediate correlation (66.7%), respectively. CONCLUSION: The MRI grading of osteochondral lesions in the talus was useful and showed a fairly good correlation with arthroscopic classification.

A "benign" sphenoid ridge meningioma manifesting as a subarachnoid hemorrhage associated with tumor invasion into the middle cerebral artery.

Meningioma rarely manifests as a subarachnoid hemorrhage (SAH), and invasion directly into a major intracranial artery is extremely rare. To the best of our knowledge, meningioma presenting with an SAH associated with major intracranial arterial invasion has never been reported. We present a case of sphenoid ridge meningotheliomatous meningioma manifesting as an SAH without pathologically atypical or malignant features, due to direct tumor invasion into the middle cerebral artery.

Cerebral infarct volume measurements to improve patient selection for endovascular treatment.

Patients who have large cerebral infarctions may not be good candidates for endovascular treatment. Various methods for determining infarct volume have been used in clinical studies. We evaluated the effectiveness of several methods for measuring infarct volume, especially regarding futile outcomes despite endovascular treatment.Patients with acute ischemic stroke in unilateral anterior circulation territory who were treated with intra-arterial thrombectomy were included. For assessing infarct volume, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) scoring system was applied to images obtained by noncontrast computed tomography (NCCT), postcontrast CT (PCCT), and diffusion-weighted imaging (DWI). DWI stroke volume was semiquantitatively measured with the manually outlined hyperintense lesion. Infarct core volume was calculated with a threshold apparent diffusion coefficient value of 600 × 10 mm/s. Intraclass correlation coefficients (ICC) were estimated to assess inter-reader reliability for ASPECTS scoring and DWI stroke volume. Receiver operating characteristic (ROC) curve analyses, and univariable and multivariable comparative analyses, were performed with each evaluation method to predict futile outcome (modified Rankin Scale score 5-6).The mean age of the included 79 patients was 65.1 ±â€Š15.7 years. Among them, 55 (69.6%) patients demonstrated successful reperfusion after intra-arterial thrombectomy, but 34 (43.0%) patients had futile outcomes. Inter-reader agreement was excellent for measurement of the DWI stroke volume (ICC, 0.973), DWI ASPECTS (0.940), and PCCT ASPECTS (0.859), but was moderate for NCCT ASPECTS (0.694). Regarding prediction of futile outcomes, area under ROC curve was 0.551 on NCCT ASPECTS and it was significantly smaller than that in PCCT ASPECTS (area under ROC 0.651, P = 0.030), DWI ASPECTS (0.733, P = 0.003), DWI stroke volume (0.702, P = 0.022), and infarct core volume (0.702, P = 0.021). Besides old age and high National Institutes of Health Stroke Scale score on admission, MRI parameters such as DWI ASPECTS and infarct core volume indicating large volumes were independently associated with futile outcomes in multivariable analyses.DWI ASPECTS can be a good parameter predicting futility, which is easily measured and has high prediction power.

A radiological classification system for talocalcaneal coalition based on a multi-planar imaging study using CT and MRI.

OBJECTIVE: To develop a radiological classification system for talocalcaneal coalition suitable for adults. METHODS AND MATERIALS: A retrospective review was performed on patients diagnosed with talocalcaneal coalition from July 2001 to November 2011. Based on the cartilaginous or bony nature, facet joint orientation and bony structure morphology, we classified talocalcaneal coalitions into four types: I (linear with or without posterior hooking), II (talar overgrowth), III (calcaneal overgrowth) and IV (complete osseous). RESULTS: Seventy feet (59 patients) with talocalcaneal coalition were evaluated by CT (61/70 feet) using multi-planar reformation and/or magnetic resonance imaging (43/70 feet). Type I, II, III and IV coalitions were detected in 45 (64 %), 10 (14 %), 13 (19 %), and 2 feet (3 %), respectively. Fracture fragments were observed in 16 feet (seven Type I and nine Type III coalitions) with hooked or overgrown calcanei and in one foot in the talus (Type I). Eleven patients had bilateral talocalcaneal coalitions; ten patients had coalitions of the same type and one had both Type I and Type III coalitions. Among 48 patients with unilateral involvement, the left and right feet were affected in 26 and 22 patients, respectively. CONCLUSIONS: A classification system for talocalcaneal coalition based on multi-planar imaging studies was developed. KEY POINTS: • A classification system for talocalcaneal coalition based on multi-planar imaging was developed. • The relative frequencies of different talocalcaneal coalition types were determined. • Fracture fragments were easily distinguished and frequently originated from the calcaneus. • Fracture fragments were mostly associated with Type I (linear) with posterior hooking and Type III (calcaneal overgrowth).