Does b1000-b0 Mismatch Challenge Diffusion-Weighted Imaging-Fluid Attenuated Inversion Recovery Mismatch in Stroke?

BACKGROUND AND PURPOSE: Our aim was to explore whether the mismatch in lesion visibility between b1000 and b0 images is an alternative to mismatch between diffusion-weighted imaging and fluid-attenuated inversion recovery imaging as a surrogate marker of stroke age. METHODS: We analyzed patients from the European multicenter I-KNOW database. Independent readers assessed the visibility of ischemic lesions of the anterior circulation on b0 and fluid-attenuated inversion recovery imaging images. The signal-intensity ratio for b0 and fluid-attenuated inversion recovery imaging images was also measured from the segmented stroke lesion volume on b1000 images. RESULTS: This study included 112 patients (68 men; mean age, 67.4 years) with stroke onset within (n=85) or longer than (n=27) 4.5 hours. b1000-b0 mismatch identified patients within 4.5 hours of stroke onset with moderate sensitivity (72.9%; 95% confidence interval [CI], 63.5-82.4) and specificity (70.4%; 95% CI, 53.2-87.6), high positive predictive value (88.6%; 95% CI, 81.1-96.0), and low negative predictive value (45.2%; 95% CI, 30.2-60.3). Global comparison of b1000-b0 mismatch with diffusion-weighted imaging-fluid-attenuated inversion recovery imaging mismatch (considered the imaging gold standard) indicated high sensitivity (85.9%; 95% CI, 78.2-93.6), specificity (91.2%; 95% CI, 76.3-98.1), and positive predictive value (96.7%; 95% CI, 88.0-99.1) and moderate negative predictive value (73.8%; 95% CI, 60.5-87.1) of this new approach. b0 signal-intensity ratio (r=0.251; 95% CI, 0.069-0.417; P=0.008) was significantly although weakly correlated with delay between stroke onset and magnetic resonance imaging. CONCLUSIONS: b1000-b0 mismatch may identify patients with ischemic stroke of the within 4.5 hours of onset with high positive predictive value, perhaps constituting an alternative imaging tissue clock.

Donepezil decreases annual rate of hippocampal atrophy in suspected prodromal Alzheimer's disease.

INTRODUCTION: The purpose of this study was to study the effect of donepezil on the rate of hippocampal atrophy in prodromal Alzheimer's disease (AD). METHODS: A double-blind, randomized, placebo-controlled parallel group design using donepezil (10 mg/day) in subjects with suspected prodromal AD. Subjects underwent two brain magnetic resonance imaging scans (baseline and final visit). The primary efficacy outcome was the annualized percentage change (APC) of total hippocampal volume (left + right) measured by an automated segmentation method. RESULTS: Two-hundred and sixteen only subjects were randomized across 28 French expert clinical sites. In the per protocol population (placebo = 92 and donepezil = 82), the donepezil group exhibited a significant reduced rate of hippocampal atrophy (APC = -1.89%) compared with the placebo group (APC = -3.47%), P < .001. There was no significant difference in neuropsychological performance between treatment groups. DISCUSSION: A 45% reduction of rate of hippocampal atrophy was observed in prodromal AD following 1 year of treatment with donepezil compared with placebo.

Sequential MR Assessment of the Susceptibility Vessel Sign and Arterial Occlusion in Acute Stroke.

PURPOSE: Susceptibility vessel sign (SVS) may likely influence recanalization after thrombolysis. We assessed, through the European sequential MRI database "I-KNOW," the relationship between the presence of SVS on T2-weighted gradient echo imaging, its angiographic counterpart on magnetic resonance angiography and its subsequent impact on recanalization after thrombolysis. MATERIALS AND METHODS: Initial clinical and MRI characteristics and early follow up were analyzed in acute ischemic stroke patients treated with rt-Pa within 4.5 hours. Patients underwent multimodal MRI at admission. Sequential imaging performed 3 hours, 2 days and 1 month later allowed the analysis of SVS changes and recanalization. RESULTS: Fifty patients were included in the study. SVS was observed in 54% of cases at admission. SVS was still present in 46% patients at 3 hours, 16% at 2 days, and 0% at 1 month. It was an independent predictor of no recanalization after thrombolysis (P = .04). After 3 hours, SVS disappeared in only 4 cases, and was not linked with recanalization on MRA. Conversely, when SVS persisted, a partial or complete recanalization was observed in 9 and 6 cases, respectively. CONCLUSIONS: SVS is a predictor of lower recanalization rate. Its disappearance is not necessarily correlated with recanalization.

CSF neopterin level as a diagnostic marker in primary central nervous system lymphoma.

BACKGROUND: The diagnosis of primary central nervous system lymphoma (PCNSL) can be challenging. PCNSL lesions are frequently located deep within the brain, and performing a cerebral biopsy is not always feasible. The aim of this study was to investigate the diagnostic value of CSF neopterin, a marker of neuroinflammation, in immunocompetent patients with suspected PCNSL. METHODS: We retrospectively reviewed the characteristics of 124 patients with brain tumor (n = 82) or an inflammatory CNS disorder (n = 42) in whom CSF neopterin levels were assessed. Twenty-eight patients had PCNSL, 54 patients had another type of brain tumor (glioma n = 36, metastasis n = 13, other n = 5), and 13 patients had a pseudotumoral inflammatory brain lesion. RESULTS: CSF neopterin levels were significantly higher in the patients with PCNSL than in those with other brain tumors (41.8 vs 5.1 nmol/L, P < .001), those with pseudotumoral inflammatory brain lesions (41.8 vs 4.3 nmol/L, P < .001), and those with nontumefactive inflammatory CNS disorders (41.8 vs 3.8 nmol/L, P < .001). In the 95 patients with space-occupying brain lesions, at a cutoff of 10 nmol/L, the sensitivity of this approach was 96% and the specificity was 93% for the diagnosis of PCNSL. The positive and negative predictive values were 84% and 98%, respectively. CONCLUSION: Assessing CSF neopterin levels in patients with a suspected brain tumor might be helpful for the positive and differential diagnosis of PCNSL. A prospective study is warranted to confirm these results.

Vascular anatomy in the lumbar spine investigated by three-dimensional computed tomography angiography: the concept of vascular window.

OBJECTIVE: To report an in vivo anatomic evaluation of prevertebral vessels in the lumbar spine using three-dimensional (3D) computed tomography (CT) angiography and to develop the concept of vascular window for surgical access to L4-5 and L5-S1 disks. METHODS: In 146 patients who were scheduled for anterior lumbar spine surgery, 3D CT angiography was performed preoperatively. Spinal disorders included degenerative disk disease (n = 120) and low-grade spondylolisthesis (n = 26). 3D reconstructions were obtained using the volume-rendering technique. Level of aortic bifurcation and iliocavum confluence, presence of the ascending iliolumbar vein, presence of the central sacral vessels, and anatomic variations were analyzed. A vascular window at L5-S1 was defined as the "free vascular" area for the anterior part of the L5-S1 disk. A vascular window at L4-L5 was defined as the "free vascular" area for the left anterolateral part of the L4-5 disk. RESULTS: The level of aortic bifurcation was most often observed at L4 (64%). The iliocavum confluence occurred most frequently at L5 (44%). The iliolumbar ascending vein and central sacral vessels were identified in 84% and 72% of cases. Five (3.5%) anatomic variations were noted: right internal iliac vein draining into the left common iliac vein in two cases and tortuous vessels in three cases. A vascular window was measured to 34.5 mm ± 12 at L5-S1 and to 23 mm ± 8 at L4-L5. The vascular window was <25 mm in approximately one in four patients at L5-S1 and in approximately two in three patients at L4-L5. CONCLUSIONS: This study confirms that vascular anatomy in the lumbar spine is characterized by a great variability that has significance for preoperative assessment. 3D CT angiography allowed for an effective evaluation of the relationships between the prevertebral vessels and the intervertebral disks at L4-L5 and L5-S1. Although adherence of vessels to the anterior ligament cannot be predicted by this technique, the concept of vascular windows investigated preoperatively by CT angiography could be helpful in predicting the need for vessel mobilization during anterior lumbar spine surgery.

Very late frontal relapse of medulloblastoma mimicking a meningioma in an adult: usefulness of 1H magnetic resonance spectroscopy and diffusion-perfusion magnetic resonance imaging for preoperative diagnosis: case report.

OBJECTIVE AND IMPORTANCE: We present a rare case of very long-term medulloblastoma relapse in an adult patient and discuss the pattern of recurrence and metabolic imaging of the tumor. CLINICAL PRESENTATION: A 45-year-old man was referred for evaluation of a frontobasal midline tumor 21 years after treatment of a cerebellar medulloblastoma by surgery followed by chemotherapy and craniospinal radiotherapy. Magnetic resonance images were suggestive of a meningioma. Several hypotheses were discussed, such as other radio-induced tumors, sarcomas, high-grade gliomas, or lymphomas (previous chemotherapy) and even recurrence of medulloblastoma. Preoperative exploration included H magnetic resonance single-voxel spectroscopy (35 and 135 ms echo time), diffusion imaging, and perfusion magnetic resonance imaging. INTERVENTION: On magnetic resonance spectroscopy, N-acetyl-aspartate and an elevated choline/creatine ratio were retrieved, with a huge unidentified peak at 1.27 parts per million (ppm). Myoinositol signal was present at both echo times. On diffusion imaging, the tumor appeared hyperintense, with a low apparent diffusion coefficient value of 0.689. In the perfusion study, the maximal relative cerebral blood volume was 2. Metabolic imaging favored the diagnosis of medulloblastoma over the initially suspected diagnosis of meningioma. The patient underwent complete removal of the tumor that was confirmed to be a metastasis of his primary medulloblastoma. The postoperative course was uneventful, and complementary courses of radiotherapy and chemotherapy were planned. CONCLUSION: Late relapse should be considered, even after several decades, on occurrence of a second intracranial tumor in this context. Our observation validates the clinical interest of preoperative metabolic imaging for brain tumors with distinctive pattern.