Functional Connectivity Analysis and Prediction of Pain Relief in Association with Spinal Decompression Surgery.

BACKGROUND: Although spinal decompression surgery is an effective treatment for myelopathy-induced upper limb pain, some postoperative patients suffer from residual pain in spite of adequate decompression. However, the neural mechanism underlying the poor outcome of pain relief is still unclear. The goal of this study was to explore the brain mechanisms involved in the poor recovery of upper limb pain after the spinal decompression surgery by using functional connectivity (FC) analysis. METHODS: In this cross-sectional study, 17 patients who underwent cervical spinal decompression surgery were included. Functional MRI (fMRI) during a tactile stimulus for each hand was performed at 1 day before and 7 days after the surgery. In total, 34 fMRI scans (17 left and right upper limbs, respectively) were obtained before and after the surgery, respectively. The patients were divided into poor-recovery and good-recovery groups, and then we searched for the FC that was related to poor-recovery. RESULTS: The poor-recovery group (n = 15) showed significantly stronger connectivity between the postcentral gyrus (postCG) and dorsolateral prefrontal cortex (DLPFC) than the good-recovery group (n = 12) preoperatively. When the cutoff value of the preoperative FC between the left postCG and right middle frontal gyrus included in DLPFC was >0.17, the sensitivity and specificity for poor recovery were 73% and 75%, respectively. CONCLUSIONS: Our study showed that FC between the postCG and DLPFC may be a predictor of pain relief. This result suggested that assessing FC can lead to more informed surgical interventions for cervical spondylotic myelopathy.

Ex Vivo Assessment of Various Histological Differentiation in Human Carotid Plaque with Near-infrared Spectroscopy Using Multiple Wavelengths.

We previously reported that near-infrared hyperspectral imaging enabled the localization of atherosclerotic plaques from outside the vessels, but not the optical characteristics of each histological component. Therefore, the near-infrared spectrum of each component was collected from the sliced section of the human carotid plaque obtained with endarterectomy and the optical characteristics were confirmed in several wavelengths. Based on this information, we assessed the diagnostic accuracy for ex vivo chemogram in each plaque component created with near-infrared spectroscopy (NIRS), using multiple wavelengths. The chemogram projected on the actual image of plaque was created based on light intensity and transmittance change at three wavelengths. The wavelengths that were mainly were 1440, 1620, 1730, and 1930 nm. We evaluated the accuracy of histological diagnosis in chemogram compared with pathological findings, analyzing interobserver agreement with κ-statistics. The chemograms that we created depicted the components of fibrous tissue, smooth muscle, lipid tissue, intraplaque hemorrhage, and calcification. Diagnostic odds ratio in each component was as follows: 259.6 in fibrous tissue, 144 in smooth muscle, 1123.5 in lipid tissue, 29.3 in intraplaque hemorrhage, and 136.3 in calcification. The κ-statistics revealed that four components, excluding intraplaque hemorrhage, had substantial or almost perfect agreement. Thus, this study demonstrated the feasibility of using chemogram focused on specific component during the histological assessment of atherosclerotic plaques, highlighting its potential diagnostic ability. Chemograms of various target components can be created by combining multiple wavelengths. This technology may prove to be useful in improving the histological assessment of plaque using NIRS.

Differential Diagnosis between Low-Grade and High-Grade Astrocytoma Using System A Amino Acid Transport PET Imaging with C-11-MeAIB: A Comparison Study with C-11-Methionine PET Imaging.

Introductions: [N-methyl-C-11]α-Methylaminoisobutyric acid (MeAIB) is an artificial amino acid radiotracer used for PET study, which is metabolically stable in vivo. In addition, MeAIB is transported by system A neutral amino acid transport, which is observed ubiquitously in all types of mammalian cells. It has already been shown that MeAIB-PET is useful for malignant lymphoma, head and neck cancers, and lung tumors. However, there have been no reports evaluating the usefulness of MeAIB-PET in the diagnosis of brain tumors. The purpose of this study is to investigate the efficacy of system A amino acid transport PET imaging, MeAIB-PET, in clinical brain tumor diagnosis compared to [S-methyl-C-11]-L-methionine (MET)-PET. Methods: Thirty-one consecutive patients (male: 16, female: 15), who were suspected of having brain tumors, received both MeAIB-PET and MET-PET within a 2-week interval. All patients were classified into two groups: Group A as a benign group, which included patients who were diagnosed as low-grade astrocytoma, grade II or less, or other low-grade astrocytoma (n=12) and Group B as a malignant group, which included patients who were diagnosed as anaplastic astrocytoma, glioblastoma multiforme (GBM), or recurrent GBM despite prior surgery or chemoradiotherapy (n=19). PET imaging was performed 20 min after the IV injection of MeAIB and MET, respectively. Semiquantitative analyses of MeAIB and MET uptake using SUVmax and tumor-to-contralateral normal brain tissue (T/N) ratio were evaluated to compare these PET images. ROC analyses for the diagnostic accuracy of MeAIB-PET and MET-PET were also calculated. Results: In MeAIB-PET imaging, the SUVmax was 1.20 ± 1.29 for the benign group and 2.94 ± 1.22 for the malignant group (p < 0.005), and the T/N ratio was 3.77 ± 2.39 for the benign group and 16.83 ± 2.39 for the malignant group (p < 0.001). In MET-PET, the SUVmax was 3.01 ± 0.94 for the benign group and 4.72 ± 1.61 for the malignant group (p < 0.005), and the T/N ratio was 2.64 ± 1.40 for the benign group and 3.21 ± 1.14 for the malignant group (n.s.). For the analysis using the T/N ratio, there was a significant difference between the benign and malignant groups with MeAIB-PET with p < 0.001. The result of ROC analysis using the T/N ratio indicated a better diagnosis accuracy for MeAIB-PET for brain tumors than MET-PET (p < 0.01). Conclusions: MeAIB, a system A amino acid transport-specific radiolabeled agents, could provide better assessments for detecting malignant type brain tumors. In a differential diagnosis between low-grade and high-grade astrocytoma, MeAIB-PET is a useful diagnostic imaging tool, especially in evaluations using the T/N ratio. Clinical trial registration: This trial was registered with UMIN000032498.

Spinal Meningioma Arising from the Denticulate Ligament.

BACKGROUND: To control bleeding during spinal meningioma surgery, early resection of the dural attachment is important. We report a case of a meningioma where identifying the tumor's dural attachment was difficult because the tumor arose from the denticulate ligament. This report histopathologically and surgically describes this rare occurrence. CASE DESCRIPTION: A 38-year-old man presented with a mass lesion that was found during a follow-up examination for vestibular schwannoma surgery performed 2 years prior. He was neurologically free of symptoms except for right-sided deafness. Magnetic resonance imaging revealed an intradural extramedullary mass at the C1 level. The tumor had homogeneous enhancement after administration of gadolinium; however, no dural tail sign was seen. Schwannoma was diagnosed, and lesion resection was performed. The hard, white tumor was adherent to the denticulate ligament, and no dural attachment was found. The tumor was totally removed after resection of the denticulate ligament. Histopathologic investigation, based on immunoreactivity to epithelial membrane antigen, revealed that the tumor was a meningioma. In addition to normal fibrous tissue, the denticulate ligament was infiltrated by tumor cells. Based on histopathologic findings and the absence of a dural attachment, we suspect that this meningioma originated from the denticulate ligament. CONCLUSIONS: If it is difficult to find the dural attachment during spinal meningioma surgery, the possibility of a denticulate meningioma should be considered, and the attachment should be resected as soon as possible.

Cortical Reorganizations for Recovery from Depressive State After Spinal Decompression Surgery.

BACKGROUND: Depressed mood following neuronal damage not only impedes functional recovery but also negatively affects quality of life for many patients. Depressed patients with cervical myelopathy often show improvement in both mood and motor function after spinal decompression surgery; however, the neural mechanism underlying this psychological benefit from surgery remains unclear. The aim of this study was to clarify the brain sites that relate to alleviation of depression after spinal decompression surgery. METHODS: We compared brain activity of patients with cervical myelopathy (n = 6) with healthy participants (n = 5) using functional magnetic resonance imaging. We then analyzed functional magnetic resonance imaging data to find the brain regions that correlated with depression severity (n = 12; 6 preoperative patients and 6 postoperative patients) and compared preoperative imaging data with postoperative imaging data from patients. RESULTS: Spinal decompression surgery alleviated depression and diminished anterior cingulate cortex activity. Simultaneously, supplementary motor area activity, which was increased in patients with myelopathy compared with control subjects, was diminished after surgery. CONCLUSIONS: Traditionally, surgical indications for myelopathy are determined by the severity of sensorimotor symptoms without considering psychological symptoms. We anticipate our results will lead to more informed surgical decisions for cervical spondylosis myelopathy.

Intraoperative FLOW 800 Analysis for Intramedullary Cystic Lesion: A Technical Case Report.

BACKGROUND AND IMPORTANCE: During intramedullary lesion surgery, the lesion site and the posterior median sulcus (PMS) should be accurately identified prior to myelotomy to avoid severe injury of the posterior funiculus. However, intramedullary lesions are fundamentally invisible until the myelotomy is performed. Furthermore, the PMS location is frequently unclear due to lesion-induced swelling or distortion of the spinal cord. Intraoperative indocyanine green videoangiography (ICG-VA) followed by FLOW 800 analysis, which shows vascularization of the spinal parenchyma, may provide a solution for these problems in specific cases. CLINICAL PRESENTATION: A 61-year-old woman suffering from claudication visited our department. Magnetic resonance imaging (MRI) revealed a cystic lesion at the level of Th11. A solid portion was not detected in the T1-weighted images following gadolinium administration. We made a diagnosis of ventriculus terminalis and performed a lesion resection. Prior to opening the PMS, ICG-VA was performed, which revealed an avascular area representing the intramedullary cyst. The PMS was the most avascular area observed in the time-intensity analysis executed using FLOW 800 software (Zeiss, Oberkochen, Germany). Thus, it was helpful in determining the site for myelotomy, which should be performed at the center of the extent of the lesion. The patient was discharged 23 days after the operation, ambulating independently. CONCLUSION: Intraoperative ICG-VA followed by FLOW 800 analysis was applied to a case of intramedullary cystic lesion. This technique may be helpful in performing safer intramedullary cystic lesion surgery because it enables visualization of the lesion location and confirmation of the PMS.

Discrepancy between radiological and histological findings in ganglioglioma of the optic chasm: Case report.

BACKGROUND: Gangliogliomas involving the optic nerve or chiasm are extremely rare tumors, which can be confused radiologically with other neoplasms. α-[N-methyl-11C]-methylaminoisobutyric acid (11C-MeAIB) is a new artificial amino acid positron emission tomography (PET) tracer, which is metabolically more stable in vivo and may be more specific for tumors than 11C-methionine. However, the utility of 11C-MeAIB PET in the diagnosis of brain tumors has not yet been reported. CASE DESCRIPTION: A 26-year-old man presented with visual field defects and headache, and magnetic resonance imaging demonstrated a suprasellar mass involving the optic chiasm. A biopsy and partial tumor resection were performed via an interhemispheric approach. We diagnosed the tumor as ganglioglioma (WHO grade I) involving the optic chiasm. Although this lesion was histologically benign, 11C-MeAIB PET, 2-deoxy-2-[18F] fluoro-D-glucose (18F-FDG) PET and proton magnetic resonance spectroscopy indicated malignant features. CONCLUSION: The discrepancy between radiological and histological findings implies that this new amino acid tracer PET may have a limitation in the diagnosis of gangliogliomas. Although further study is necessary, gangliogliomas should be included in the differential diagnosis of suprasellar tumors, even if PET findings show malignant features.

In vivo detection of atherosclerotic plaque using non-contact and label-free near-infrared hyperspectral imaging.

BACKGROUND AND AIMS: Detecting detailed atherosclerotic plaques is important to reduce risk factors during surgery. However, there are few methods to evaluate them during surgery. The aim of this study was to establish an in vivo, non-contact, and label-free imaging method for identifying atherosclerotic plaque lesions from outside vessels with a diffuse-reflectance near-infrared (NIR) hyperspectral imaging (HSI) system. METHODS: NIR spectra between 1000 and 2350 nm were measured using an NIR HSI imaging system outside the exposed abdominal aorta in five Watanabe Heritable Hyperlipidemic (WHHL) rabbits in vivo. Preprocessed data were input to a supervised machine learning algorithm called a support vector machine (SVM) to create pixel-based images that can predict atherosclerotic plaques within a vessel. The images were compared with histological findings. RESULTS: Absorbance was significantly higher in plaques than in normal arteries at 1000-1380, 1580-1810, and 1880-2320 nm. Overall predictive performance showed a sensitivity of 0.814 ± 0.017, a specificity of 0.836 ± 0.020, and an accuracy of 0.827 ± 0.008. The area under the receiver operating characteristic curve was 0.905 (95% confidence interval = 0.904-0.906). CONCLUSIONS: The NIR HSI system combined with a machine learning algorithm enabled accurate detection of atherosclerotic plaques within an internal vessel with high spatial resolution from outside the vessel. The findings indicate that the NIR HSI system can provide non-contact, label-free, and precise localization of atherosclerotic plaques during vascular surgery.

Usefulness of four-dimensional computed tomographic angiography in a vertebral artery dissection case.

Discrimination of intramural hematoma from intra-aneurysmal blood flow is a critical issue for determining the necessity of treatment in vertebral artery dissection (VAD) cases. We describe modified four-dimensional computed tomographic angiography (4D-CTA) that is useful for evaluating blood flow in a dissected vertebral artery in a 41-year-old man who was diagnosed as VAD. Magnetic resonance angiography (MRA) showed a growth of intramural hematoma, which was confusingly similar to intra-aneurysmal blood flow. Modified 4D-CTA enabled us to discriminate the intramural hematoma from blood flow because of its fine time and spatial resolution. Modified 4D-CTA may be a substitute for angiography in VAD cases.

[Two cases of spontaneous cervical epidural hematoma mimicking cerebral infarction].

Spontaneous spinal epidural hematoma(SSEH)is a rare condition that typically presents with acute back pain and paraparesis or quadriparesis. However, hemiparesis is a rare initial symptom of SSEH. Here, we report two cases of SSEH presenting with hemiparesis, which were difficult to distinguish from cerebral stroke. In both cases, source images of MR angiography were useful for the diagnosis of SSEH. The first patient was an 84-year-old man who presented with monoparesis in the left lower extremity, without back pain. He was initially misdiagnosed with a cerebral stroke and treated inappropriately with antiplatelet agents. Five days after admission, the correct diagnosis of SSEH was made based on cervical magnetic resonance imaging. Source images of cervical MR angiography also revealed SSEH. He was managed conservatively because of his relatively mild symptoms and stable condition, and his symptoms improved by rehabilitation. The second patient was a 72-year-old woman who presented with right hemiparesis and back pain. Source images of cervical MR angiography revealed a right posterolateral epidural hematoma, and underwent emergency surgical decompression and hematoma removal. We emphasize that SSEH should be considered in the differential diagnosis for patients with acute hemiparesis, even though they do not complain of back pain, and that source images of neck MR angiography could be useful for quickly screening for SSEH.

Different modalities of treatment of intracranial mycotic aneurysms: Report of 4 cases.

BACKGROUND: Intracranial mycotic aneurysms, although rare neurovascular pathology, represented a neurosurgical challenge that required careful stepwise decision making. Different approaches for their management were used. We present our experience with 4 patients treated in terms of indications and efficacy of different treatment modalities. METHODS: Four patients with infective endocarditis and 5 intracranial mycotic aneurysms were treated during the last 5 years. All of the patients were men; their ages ranged between 29 and 62 years (mean, 47.3 years). Distal MCA was the commonest site (3 patients) of aneurysm, 1 was located at the distal PCA, whereas the remaining aneurysm was at the distal ACA. Angiographic studies were done in 2 patients because of neurologic signs and for screening in 2 patients with documented endocarditis. RESULTS: One patient was treated conservatively because of his moribund general condition; 1 patient was treated with direct surgical clipping; 1 patient was treated with surgical trapping and resection of the aneurysm without revascularization; and the remaining patient, harboring 2 distal mycotic aneurysms, was treated with selective embolization for his PCA aneurysm and endovascular trapping for the distal ACA aneurysm. Follow-up angiographic results showed stable occlusion of the aneurysms. No periprocedural technical complications were reported, and none of the patients, including the patient with medical treatment only, has ever experienced new neurologic events after definitive treatment. CONCLUSIONS: Prolonged courses of antibiotics are recommended for all patients with mycotic aneurysms. Selective endovascular embolization or trapping with soft and ultrasoft electrolytically detachable coils seems to be an effective technique that should be considered for treatment of dynamic unruptured mycotic aneurysms, with conventional surgical repair restricted for ruptured aneurysms with associated hematoma and high intracranial pressure.

Endovascular embolization vs surgical clipping in treatment of cerebral aneurysms: morbidity and mortality with short-term outcome.

BACKGROUND: Endovascular embolization of cerebral aneurysms has evolved rapidly worldwide within the last years, and has gained more popularity at the expense of surgical clipping; however, both regimens have inherent risks. This study was undertaken to asses the cerebral complications associated with both modalities of cerebral aneurysm treatment. METHODS: We retrospectively reviewed the charts, operative and embolization reports, and imaging of patients who underwent surgical clipping or embolization for cerebral aneurysms at our institution between October 2001 and October 2004. Patients were divided into 2 groups: group A, patients who had confirmed subarachnoid hemorrhage; group B, patients with unruptured cerebral aneurysms. Patients belonging to group A were evaluated according to the Hunt and Hess scale with their computed tomography scan evaluated according to Fisher scale. Short-term outcome was measured with Glasgow Outcome Scale for both groups. RESULTS: One hundred thirty-three patients with 168 aneurysms were treated; 95 (71.4%) were women and 38 (28.6%) men; mean age was 60.28 years. Hypertension (29.6%) was the most commonly encountered risk factor; average size of aneurysms treated was 7.21 mm; 53 patients belonged to group A. Seven patients were Hunt and Hess grade I, 23 grade II, 11 grade III, 7 grade IV, and 5 grade V. Eighty patients belonged to group B; for both groups, the periprocedural technical complication rate associated with coiling was 8.4% vs 19.35% with clipping. Follow-up angiographic results were better with clipping, as total aneurysm occlusion was 81.4% vs 57.5% with coiling. In group A, the incidence of angiographic vasospasm was 17.4% vs 45.4% with coiling vs clipping, whereas the incidence of shunt-dependant hydrocephalus was comparable with embolization and clipping. In group A, excellent outcome was achieved in 62% vs 44% (endovascular vs surgical) of subgroups, whereas in group B, it was 93% vs 81%, respectively. CONCLUSION: With rapidly evolving technology of endovascular embolization, accumulated experience, and good selection of patients with optimum angioanatomical criteria and endovascular accessibility, our results of morbidity and mortality associated with both modalities of cerebral aneurysm treatment with short-term outcome show that endovascular embolization of cerebral aneurysms is a safe alternative to surgical clipping in the treatment of both ruptured and unruptured cerebral aneurysms; however, long-term outcome needs to be evaluated.