Anatomy of the Frontal Sinus Drainage Pathway Evaluated in 247 Cadavers to Prevent Cerebrospinal Fluid Leakage After Frontobasal Craniotomy.

BACKGROUND AND OBJECTIVES: The frontal sinus (FS) drainage pathway (FSDP) may be a conduit for cerebrospinal fluid leakage after frontobasal craniotomy. In this cadaveric study, we aimed to evaluate the anatomy of the FSDP. METHODS: The FSs and FSDPs of 247 cadavers were investigated. We counted the number of FSs and FSDPs in each half-head, verified the presence of a narrowing section in each FSDP, and evaluated the depth, shape, and size of each narrowing FSDP section. RESULTS: We investigated 494 sides and 472 FSDPs of 247 cadavers. FSs were unilaterally undeveloped in 13 of 247 cadavers (5.3%) and bilaterally in 8 (3.2%). FSs were unilaterally duplicated in 7 of 247 cadavers (2.8%), and no FSs were bilaterally duplicated or triplicated. No FSs had 2 or more FSDPs, and all 472 investigated FSDPs were invariably narrowed at various depths. The narrowing FSDP sections were elliptical (78.6%), circular (18.1%), triangular (1.8%), or crescent-shaped (1.4%) and of varying thickness and orientation. Although FSDPs were asymmetric in 92.2% of cadavers and narrowing FSDP sections were located deep (8.9 ± 4.4 mm from the anterior skull base), the narrowing FSDP sections were typically small (area: 5.9 ± 3.3 mm 2 ) or thin (short diameter: 2.1 ± 0.7 mm). CONCLUSION: Each FS had only one FSDP, all FSDPs were invariably narrowed at various depths, and the narrowing FSDP sections were sufficiently small or thin to allow local closure, facilitating prevention of cerebrospinal fluid leakage after frontobasal craniotomy.

[Monitoring of the Floor of the 4th Ventricle for Brainstem Surgery].

The brainstem is densely aggregated with important cranial nerve nuclei and nerve tracts. Surgery in this area is, therefore, risky. Not only anatomical knowledge but also electrophysiological monitoring is essential for brainstem surgery. The facial colliculus, obex, striae medullares, and medial sulcus are important visual anatomical landmarks at the floor of the 4th ventricle. As cranial nerve nuclei and nerve tracts deviate by lesion, it is important to have a firm image of the cranial nerve nuclei and nerve tracts before making an incision in the brainstem. The entry zone into the brainstem is selected where the parenchyma is the thinnest due to the lesions. The suprafacial or infrafacial triangle is often used as an incision site for the floor of the 4th ventricle. In this article, we introduce the electromyographic method of observing the external rectus muscle; orbicularis oculi muscle; orbicularis oris muscle; and tongue; and two cases in which monitoring was used(the pons and medulla cavernoma cases). By examining surgical indications in this way it may be possible to improve the safety of such operations.

Single-Cell Analysis of Unidirectional Migration of Glioblastoma Cells Using a Fiber-Based Scaffold.

Glioblastoma (GBM) is a malignant incurable brain tumor in which immature neoplastic cells infiltrate brain tissue by spreading along nerve fibers. The aim of the study was to compare the migration abilities of glioma cells with those of other cancer cells and elucidate the migratory profiles underlying the differential migration of glioma cells using a fiber-based quantitative migration assay. Here, wound healing and transwell assays were used to assess cell mobility in four cell lines: U87-MG glioblastoma cells, MDA-MB-231 breast cancer cells, HCT116 colorectal cancer cells, and MKN45 gastric cancer cells. We also assessed cell mobility using a fiber model that mimics nerve fibers. Time-lapse video microscopy was used to observe cell migration and morphology. The cytoskeleton arrangement was assessed in the fiber model and compared with that in the conventional cell culture model. The conventional evaluation of cell migration ability revealed that the migration ability of breast cancer and glioblastoma cell lines was higher than that of colon cancer and gastric cancer cell lines. The fiber model confirmed that the glioblastoma cell line had a significantly higher migration ability than other cell lines. Tubulin levels were significantly higher in the glioblastoma cells than in other cell lines. In conclusion, the developed fiber-based culture model revealed the specific migratory profile of GBM cells during invasion.

Assessment of Arterial Transit Time and Cerebrovascular Reactivity in Moyamoya Disease by Simultaneous PET/MRI.

We investigated the relationship between MRI-arterial spin labeling (ASL) parameters and PET-cerebral blood flow (CBF)/cerebrovascular reactivity (CVR) simultaneously obtained by PET/MRI in Moyamoya disease. Twelve patients underwent 15O-water PET/MRI with the acetazolamide (ACZ) challenge test. PET-CBF and PET-CVR were measured using 15O-water PET. Pseudo-continuous ASL obtained the robust arterial transit time (ATT) and ASL-CBF estimation. ASL parameters were compared with PET-CBF and PET-CVR. Before ACZ loading, absolute and relative ASL-CBF were significantly correlated with absolute and relative PET-CBF (r = 0.44, p < 0.0001, and r = 0.55, p < 0.0001, respectively). After ACZ loading, absolute and relative ASL-CBF were significantly correlated with absolute and relative PET-CBF (r = 0.56, p < 0.001, and r = 0.75, p < 0.0001, respectively), and ΔASL-CBF was significantly correlated with ΔPET-CBF (r = 0.65, p < 0.0001). Baseline ASL-ATT had strong negative correlations with ΔPET-CBF and PET-CVR (r = -0.72, p < 0.0001, and r = -0.66, p < 0.0001, respectively). Baseline ASL-ATT of MCA territories with CVR <30% (1546 ± 79 ms) was significantly higher than that with CVR > 30% (898 ± 197 ms). ASL-ATT ratio of MCA territories with CVR < 30% (94.0 ± 10.5%) was significantly higher than that with CVR > 30% (81.4 ± 11.3%). ATT correction using multiple postlabeling delays increased the accuracy of ASL-CBF quantitation. Baseline ASL-ATT is a hemodynamic parameter and may represent an efficient alternative to PET-CVR.

The Utility of Arterial Transit Time Measurement for Evaluating the Hemodynamic Perfusion State of Patients with Chronic Cerebrovascular Stenosis or Occlusive Disease: Correlative Study between MR Imaging and 15O-labeled H2O Positron Emission Tomography.

PURPOSE: To verify whether arterial transit time (ATT) mapping can correct arterial spin labeling-cerebral blood flow (ASL-CBF) values and to verify whether ATT is a parameter that correlates with positron emission tomography (PET)-oxygen extraction fraction (OEF) and PET-mean transit time (MTT). METHODS: Eleven patients with unilateral major cerebral artery stenosis or occlusion underwent MRI and PET in the chronic or asymptomatic phase. ASL-MRI acquisitions were conducted with each of two post-label delay (PLD) settings (0.7s and 2.0s) using a pseudo-continuous ASL pulse sequence and 3D-spin echo spiral readout with vascular crusher gradient. ATT maps were obtained using a low-resolution pre-scan approach with five PLD settings. Using the ASL perfusion images and ATT mapping, ATT-corrected ASL-CBF images were obtained. Four kinds of ASL-CBF methods (PLD 0.7s with or without ATT correction and PLD 2.0s with or without ATT correction) were compared to PET-CBF, using vascular territory ROIs. ATT and OEF were compared for all ROIs, unaffected side ROIs, and affected side ROIs, respectively. ATT and MTT were compared by the ratio of the affected side to the unaffected side. Transit time-based ROIs were used for the comparison with ATT. RESULTS: Comparing ASL-CBF and PET-CBF, the correlation was higher with ATT correction than without correction, and for a PLD of 2.0s compared with 0.7s. The best correlation was for PLD of 2.0s with ATT correction (R2 = 0.547). ROIs on the affected side showed a low but significant correlation between ATT and PET-OEF (R2 = 0.141). There was a low correlation between the ATT ratio and the MTT ratio (R2 = 0.133). CONCLUSION: Low-resolution ATT correction may increase the accuracy of ASL-CBF measurements in patients with unilateral major cerebral artery stenosis or occlusion. In addition, ATT itself might have a potential role in detecting compromised hemodynamic state.

Potential of Rice-Flour Jelly Made from High-Amylose Rice as a Dysphagia Diet: Evaluation of Pharyngeal Residue by FEES.

Dysphagia diets are recommended to prevent choking and aspiration in people with dysphagia; however, rice-porridge and mashed rice-porridge, which are used as staple foods for people with dysphagia in Japan, are time-consuming to prepare. The National Agriculture and Food Research Organization has found jelly-like food products made from high-amylose rice-flour (rice-flour jelly) to be easy to prepare with a texture suitable for dysphagia diets. To investigate the potential of rice-flour jelly for the dysphagia diet, we evaluated the amount of pharyngeal residue after swallowing rice-flour jelly using fiberoptic endoscopic evaluation of swallowing and compared it with those of rice-porridge, mashed rice-porridge, and fruit jelly. We enrolled 70 participants (43 males and 27 females, aged 32-96 years, median 74.5 years) and evaluated their pharyngeal residue using the Yale Pharyngeal Residue Severity Rating Scale which includes five levels from I (none) to V (severe). Statistical analysis showed that level I was more common in fruit jelly for vallecula residue and pyriform sinus residue, and level III (mild) was more common in rice-porridge for vallecula residue (p < 0.05). No differences of pharyngeal residue were found in rice-flour jelly or mashed rice-porridge. No significant difference was observed in the number of participants with laryngeal penetration or aspiration. Therefore, rice-flour jelly is a suitable alternative to rice-porridge as a staple food for people with dysphagia in terms of food texture.

Cerebrovascular Treatment with Superselective Balloon Test Occlusion for Multiple Cerebral Aneurysms Associated with Middle Cerebral Artery Anomaly: A Case Report.

A 38-year-old woman presented with impaired consciousness and anisocoria due to a subarachnoid hemorrhage and an intracerebral hemorrhage of the left temporal lobe. Examination revealed severe tortuosity in the left middle cerebral artery and three sequential bead-like aneurysms. She underwent a craniotomy in the acute phase to stop rebleeding at the rupture site and remove the intracerebral hematoma. During the chronic phase, endovascular treatment with superselective balloon test occlusion (ssBTO) was performed for the remaining aneurysms. Preoperative ssBTO was useful in evaluating collateral circulation and assessing the curability of the treatment.

[A case of left dysgeusia due to hemorrhage near the left superior cerebellar peduncle].

We report a rare case with unilateral dysgeusia due to cerebrovascular disease. A 45-year-old man was admitted to the hospital with a sudden onset of dysesthesia in the right face and upper and lower limbs. A CT scan revealed a left pontine hemorrhage. A day after onset, the patient became aware of unilateral dysgeusia. Electrogustometry showed significantly higher thresholds in the left chorda tympani nerve and glossopharyngeal nerve compared to the right nerves. We diagnosed the hemorrhage caused unilateral dysgeusia. Although dysesthesia in the right face and upper and lower limbs disappeared, the dysgeusia in the left tongue persisted six months after symptom onset. Based on the neurological and radiological findings in this case, we discuss the central gustatory pathway with literatures.

Functional Outcomes of Microsurgical Resection for Cavernous Malformations of the Brainstem.

Long-term functional outcomes of microsurgical resection for cavernous malformations of the brainstem (CMB) have been largely unknown. Favorable outcomes after CMB surgery might be related to the achievement of complete resection and mRS at 1 month after the surgery. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms tended to improve after surgery.We evaluated 25 consecutive patients with CMB surgically treated at our center between 2006 and 2021. The subjects included 11 men and 14 women, with ages ranging from 13 to 61 years (mean ± SD = 37 ± 12 years). Modified Rankin Scale (mRS) scores and neurological symptoms of the patients were evaluated before surgery, 1 month after surgery, and at the final follow-up at the outpatient clinic. The mean number of previous hemorrhages was 7 ± 1.0 and the mean lesion size was 21 ± 8 mm. The mRS scores on admission and at the final follow-up were 2.9 points and 1.7 points, respectively. The mRS scores at the final follow-up were significantly improved compared to those on admission. There was no statistical difference between the preoperative mRS and mRS at 1 month after the operation. Multivariable analysis indicated that mRS scores at 1 month after surgery were the most significant predictive factors for favorable outcomes. Complete resection was achieved in 24 of 33 operations. Incomplete resection was significantly related to the frequency of subsequent recurrent hemorrhage and high mRS scores at the final follow-up. Preoperative sensory, cerebellar, trigeminal nerve, and lower cranial nerve symptoms improved significantly after surgery.

Differences in Hemodynamic Alteration between Atherosclerotic Occlusive Lesions and Moyamoya Disease: A Quantitative 15O-PET Study.

To clarify the differences in hemodynamic status between atherosclerotic steno-occlusive lesions (SOL) and moyamoaya disease (MMD), hemodynamic parameters were compared using 15O-PET. Twenty-four patients with unilateral SOL (67 ± 11 y) and eighteen with MMD (33 ± 16 y) were assigned to this study. MMD patients were divided into twelve unilateral and six bilateral lesions. All patients underwent 15O-PET to measure cerebral blood flow (CBF), blood volume (CBV), oxygen extraction fraction (OEF), and metabolic rate (CMRO2). Acetazolamide was administered after the baseline scan and the second 15O-water PET was performed to evaluate cerebrovascular reactivity (CVR). For the CBF calculation in 15O-water PET, the three-weighted integral method was applied based on a one-tissue compartment model with pixel-by-pixel delay correction to measure precise CBF and arterial-to-capillary blood volume (V0). Baseline hemodynamic parameters showed significantly lower CBF, V0, and CMRO2, but greater CBV, OEF, and delay (p < 0.01) in the affected hemispheres than in the unaffected hemispheres. After ACZ administration, both hemispheres showed a significant increase in CBF (p < 0.0001), but not in V0. CVR differed significantly between the hemispheres. The arterial perfusion pressure of the functioning arterial part tended to be reduced after acetazolamide administration in patients with past neurologic events caused by hemodynamic impairment. MMD patients showed greater inactive vascular and venous volumes compared with common atherosclerotic SOL patients. The hemodynamic status of cerebral circulation may vary according to the chronic process of steno-occlusive change and the development of collateral circulation. In order to evaluate physiologic differences between the two diseases, 15O-PET with an acetazolamide challenge test is useful.

Needle Parking Interrupted Suturing Technique for Microvascular Anastomosis: A Technical Note.

BACKGROUND: Interrupted and continuous suturing are 2 common techniques for microvascular anastomosis in cerebrovascular surgery. One of the technical complexities of interrupted suturing includes the risk of losing the needle in between interrupted sutures during knot tying, which may result in unnecessary movements and wasted time. OBJECTIVE: To report a new needle parking technique for microvascular anastomosis that addresses a needle control problem during interrupted suturing. METHODS: The needle parking technique involves puncturing both vessel walls at the site of the next provisional suture and leaving the needle parked in place while the knots at the first suture are being made. The thread is then cut, the needle is pulled through, and the process is repeated. Illustrative cases in which the needle parking technique was used are presented. We also compared time of anastomosis completion between the conventional interrupted, needle parking interrupted, and continuous suturing techniques during an in vitro study on standardized artificial vessels. RESULTS: This technique is being used successfully by the senior author for various cerebrovascular bypass surgeries. The in vitro study demonstrated that the needle parking technique can be significantly faster than the conventional interrupted suturing technique and may be as fast as continuous suturing. CONCLUSION: Needle parking technique is a modification of conventional interrupted suturing and solves the problem of losing the needle during knot tying. This technique is simple, prevents unnecessary movements, and may result in a faster anastomosis time.

Development of a Scoring System to Predict Prolonged Post-Stroke Dysphagia Remaining at Discharge from a Subacute Care Hospital to the Home.

BACKGROUND: Prolonged dysphagia is an important stroke-related complication that imposes a substantial burden on patients and families. However, simple scoring tool to predict prolonged dysphagia is not existing. MATERIALS AND METHODS: This retrospective cohort study used data from April 2010 to March 2016. Adult patients with first-ever stroke were included. The outcome was swallowing function at discharge from the subacute care hospital to the patient's home. We collected the following factors obtained at discharge from the University of Fukui Hospital: age, sex, type of stroke, comorbidities, smoking status, alcohol use, denture use, functional dependency in daily living before admission, National Institutes of Health Stroke Scale score (NIHSS) at admission, and Functional Independence Measure(FIM). Data were divided into a training set (70%) and test set (30%). Lasso and logistic regression were used for feature selection, a scoring system was then developed, and its prediction performance evaluated. RESULTS: This study enrolled 462 patients with acute stroke. Using lasso and logistic regression, three variables (functional dependency before admission, Functional Independence Measure [FIM]-cognitive and FIM-motor scores at transfer) remained statistically significant predictors of prolonged dysphagia. Risk scores were categorized as low risk (0-2), moderate risk (3-4), and high risk (5-7), with dysphagia rates of 0%-1%, 13%-29%, and 50%-100%, respectively. A newly developed score ≥3 was the optimal cutoff for identifying patients with the potential risk of prolonged dysphagia (C-statistics, 0.92 in the test set). CONCLUSION: The developed scoring system is simple and has a high performance in predicting prolonged dysphagia after acute stroke.

[Fatal Acute Brain Swelling after Clipping of Unruptured Anterior Communicating Aneurysm: A Case Report].

There have been few reports about acute brain swelling caused by unruptured aneurysm surgery. We report a case of fatal acute brain swelling after clipping of an unruptured anterior communicating artery aneurysm following lung cancer surgery. A 65-year-old man underwent aneurysm neck clipping for an unruptured anterior communicating artery aneurysm by interhemispheric approach 35 days after curative resection of lung cancer. Immediately after the operation, his recovery from anesthesia was prolonged and anisocoria developed. Therefore, we performed emergent reoperation and encountered acute brain swelling necessitating decompressive craniectomy. Despite intensive medication including barbiturate therapy, the patient died 4 days after the operation. Autopsy revealed that brain swelling was caused by congestion with thrombus in the superior sagittal sinus apart from the site of the craniotomy. Fatal sinus thrombosis might develop during neurosurgical operation in patients with cancer.

A Case of the So-Called Posterior Condylar Canal Dural Arteriovenous Fistula with an Osseous Shunt.

Objective: The authors describe a case of the so-called dural arteriovenous fistula (DAVF) around the posterior condylar canal (PCC). Case Presentation: A 71-year-old woman presented with pulse-synchronous bruit on the left side. Conventional DSA demonstrated the following: There were many feeders, including the ascending pharyngeal artery (APA), the occipital artery (OA), and the vertebral artery (VA), to the DAVF around the PCC. Shunt flow from the posterior condylar vein (PCV) drained the suboccipital cavernous sinus (SCS) and sigmoid sinus (SS), and there was venous reflux into the inferior petrosal sinus (IPS). The patient was diagnosed with PCC DAVF and underwent transvenous embolization (TVE) with coils. Intraoperative 3D-rotational angiography (RA) and axially reconstructed images revealed an osseous shunt within the occipital bone adjacent to the PCC. The arteriovenous (AV) shunt and other symptoms disappeared after occluding the drainage route from the osseous shunt to the PCV. Conclusion: There are only three previous reports of PCC DAVF, being rare. However, no report clearly described the shunt point of PCC DAVF. 3D-RA and axially reconstructed images were useful to find and treat the shunt point.

[A Case of Putaminal Hemorrhage Caused by Underlying Tectal Glioblastoma].

We report a case of glioblastoma due to putaminal hemorrhage. Notably, the glioblastoma was located at some distance from the hematoma. A 42-year-old right-handed man presented with a sudden-onset headache, motor aphasia, and right hemiplegia. CT showed left putaminal hemorrhage and a mass lesion with a slightly high density in the midbrain away from the hematoma. Conservative treatment was initiated for the patient. Initially, we suspected a benign tumor-like cavernous malformation based on the CT findings. However, MRI showed ring enhancement of the mass lesion on contrast-enhanced MRI and hyperintensity on arterial spin labeling(ASL). A part of the wall of the putaminal hemorrhage also exhibited hyperintensity on ASL. Since we suspected a malignant brainstem tumor and a secondary intracerebral hemorrhage caused by this tumor, we performed a stereotactic brain biopsy. Histological examination revealed that the tumor was a wild-type IDH-1 glioblastoma. In the acute phase, the intracerebral hemorrhage presented as a hyperintensity on T1-weighted imaging. Therefore, it was difficult to distinguish hemorrhagic glioblastoma from an intracerebral hemorrhage. Even if an intracerebral hemorrhage is observed at common sites, it is important to consider the possibility of a malignant brain tumor and complete a prompt examination. In addition, ASL imaging may be useful in detecting hemorrhagic malignant brain tumors.

[Optic Neuropathy Secondary to Compression by the Internal Carotid Artery Concomitant with an Inflammatory Granuloma:A Case Report].

A 77-year-old man presented with a 6-month history of progressive right optic neuropathy secondary to compression by the ipsilateral internal carotid artery(ICA). We performed anterior clinoidectomy and optic canal unroofing. Subsequently, we wrapped the ICA with a polytetrafluoroethylene tape, pulled the vessel laterally, and sutured the tape to the dura mater at the anterior skull base for optimal decompression. An inflammatory mass lesion was observed around the ICA, which led to further compression of the optic nerve. Histopathological examination of the resected specimen showed an inflammatory granuloma. The patient's visual field deficit showed partial improvement postoperatively. Transposition using a tape might be an effective surgical alternative for compressive optic neuropathy.

Quantitative Analysis of the Far-Lateral, Supra-Articular Transcondylar Transtubercular Approach Using Cadaveric Computed Tomography and Magnetic Resonance Imaging.

BACKGROUND: Removing the jugular tubercle (JT) is regarded as an important step in the far-lateral approach; however, few cadaveric studies have objectively evaluated it. OBJECTIVE: To quantitatively analyze the effect of JT removal in the far-lateral approach, using cadaveric computed tomography (CT) and magnetic resonance (MR) imaging. METHODS: The far-lateral, supra-articular transcondylar transtubercular approach was employed on 23 sides of 13 formalin-fixed cadaveric heads. CT bone images were obtained before and after JT removal, and MR images were obtained before dissection and were merged with the CT bone images. The angles of attack used to approach the ventral region of the medulla, the distances between the medulla and the bony structure, and the volume of the paramedullary space were measured at the level of the JT on axial CT-MR fusion images. The values obtained after JT removal were compared with those obtained before JT removal. RESULTS: All evaluated values were significantly increased after JT removal, including the angle of attack at the level of the JT (29.8 ± 7.4° vs 58.2 ± 15.5°, P < .001), the distance between the olive and the JT (6.4 ± 2.0 mm vs 9.5 ± 5.0 mm, P = .01), and the volume of the space around the medulla (0.28 ± 0.04 cm3 vs 0.47 ± 0.09 cm3, P < .001). CONCLUSION: The paramedullary surgical working space widened by JT removal was quantitatively demonstrated in the cadaveric CT and MR imaging study. The measurement methods in this study can be applied to clinical cases and other skull base cadaveric studies.

Early and midterm results of treatment of giant internal carotid artery paraclinoid aneurysms with trapping and flow diverters.

BACKGROUND: Flow diverter devices (FDD) carry risks of postoperative complications when treating aneurysms with wide necks, stenosis, and severe tortuosity of the parent vessel. In this study, we evaluated early and midterm results for the treatment of giant paraclinoid aneurysms managed by trapping and endovascular deployment of FDD. METHODS: Medical records were analyzed for patients with giant paraclinoid aneurysms treated between July 2008 and December 2017 at National Centre for Neurosurgery with either a flow diverter or by trapping the aneurysm with or without extracranial-intracranial (EC-IC) bypass surgery. We recorded age, sex, clinical presentation, treatment modality, morbidity, and mortality. Clinical outcomes were assessed using a modified Rankin scale (mRS). RESULTS: Among 29 consecutive patients, 13 were treated with FDD, and 16 patients were managed by trapping the aneurysm, where 7/16 cases had preliminary EC-IC bypass. Of 16 trapping patients, six were trapped endovascularly and ten were trapped surgically. During the follow-up period (mean 33 months, range 6-96), total exclusion of the aneurysm from the circulation was observed 100% of aneurysms in the trapping group and 84.6% in the FDD group (P = 0.192). Early postoperative morbidity was observed in three (23%) cases in the FDD group, and four (25%) in trapping group (P = 0.525). The FDD group had one (7.7%) fatal complication due to stent occlusion and severe ischemic stroke after three months postoperatively, despite appropriate antiplatelet therapy. There were no mortalities in the trapping group (P = 0.149). The rate of mRS 0-2 did not differ significantly across groups at discharge (81.3% vs. 69.2%; P = 0.667), and all patients had mRS 0-2 at follow-up (P = 1.000). CONCLUSIONS: FDD deployment for giant paraclinoid aneurysms results in comparable angiographic and clinical outcomes to aneurysm trapping. Despite implementation of modern endovascular treatment methods, aneurysm trapping remains a valuable treatment option in carefully selected patients with giant paraclinoid aneurysms.

No significant difference found in PET/MRI CBF values reconstructed with CT-atlas-based and ZTE MR attenuation correction.

BACKGROUND: Accurate attenuation correction (AC) is one of the most important issues to be addressed in quantitative brain PET/MRI imaging. Atlas-based MRI AC (AB-MRAC), one of the representative MRAC methods, has been used to estimate the skull attenuation in brain scans. The zero echo time (ZTE) pulse sequence is also expected to provide a better MRAC estimation in brain PET scans. The difference in quantitative measurements of cerebral blood flow (CBF) using H215O-PET/MRI was compared between the two MRAC methods, AB and ZTE. METHOD: Twelve patients with cerebrovascular disease (4 males, 43.2 ± 11.7 years) underwent H215O-PET/MRI studies with a 3-min PET scan and MRI scans including the ZTE sequence. Eleven of them were also studied under the conditions of baseline and 10 min after acetazolamide administration, and 2 of them were followed up after several months interval. A total of 25 PET images were reconstructed as dynamic data using 2 sets of reconstruction parameters to obtain the image-derived input function (IDIF), the time-activity curves of the major cerebral artery extracted from images, and CBF images. The CBF images from AB- and ZTE-MRAC were then compared for global and regional differences. RESULTS: The mean differences of IDIF curves at each point obtained from AB- and ZTE-MRAC dynamic data were less than 5%, and the differences in time-activity curves were very small. The means of CBF from AB- and ZTE-MRAC reconstructions calculated using each IDIF showed differences of less than 5% for all cortical regions. CBF images from AB-MRAC tended to show greater values in the parietal region and smaller values in the skull base region. CONCLUSION: The CBF images from AB- and ZTE-MRAC reconstruction showed no significant differences in regional values, although the parietal region tended to show greater values in AB-MRAC reconstruction. Quantitative values in the skull base region were very close, and almost the same IDIFs were obtained.