Intracerebral hemorrhage is a severe type of stroke with high morbidity and mortality. Accurate assessment of hemorrhage phase is essential for determining treatment strategies, but magnetic resonance imaging evaluation remains subjective and lacks standardized criteria. This study aimed to create an objective method for estimating the phase of intracerebral hemorrhage using multi-sequence magnetic resonance imaging with 6 sequences: T1-weighted imaging, T2-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient map, fluid-attenuated inversion recovery, and T2 star-weighted magnetic resonance angiography. We retrospectively analyzed 56 patients with intracerebral hemorrhage. Magnetic resonance images used in this study were acquired using GE 1.5T scanners. Relative signal intensities were calculated using the pons as a reference, and a hemorrhage map was generated using color-coding pixels according to the 5 hemorrhage phases. Seven observers performed visual evaluations under 2 conditions: conventional image sets and hemorrhage maps. Diagnostic performance was assessed using precision-recall curves, average precision, and mean average precision. Interobserver agreement was evaluated using Fleiss' κ coefficient. The mean average precision of visual evaluation with the hemorrhage map was significantly higher than that of visual evaluation with original images (0.81 vs. 0.57, p < 0.01). Visual evaluation with hemorrhage map achieved “Almost perfect agreement” (κ = 0.85), whereas visual evaluation with original images demonstrated only “Slight agreement” (κ = 0.06). This study developed a novel diagnostic support method for estimating intracerebral hemorrhage phase using multi-sequence magnetic resonance imaging. By visualizing relative signal intensity as a color-coded hemorrhage map, the proposed method significantly improved both diagnostic accuracy and interobserver agreement compared with conventional visual evaluation.

Intra-aneurysmal thrombus formation is crucial for the healing of endovascularly treated aneurysms. This study evaluated whether T1-weighted black blood imaging can monitor thrombus formation by examining the relationship between chronological signal intensity changes and aneurysm occlusion status after flow diverter stenting and coil embolization. We retrospectively analyzed 78 patients with 83 aneurysms (flow diverter stenting: 28, coil embolization: 55) who underwent T1-weighted black blood imaging at 1 week, 3 months, and 6 months post-treatment. Relative signal intensity was calculated as the signal intensity of the aneurysmal sac divided by the signal intensity of the genu of the corpus callosum. Satisfactory occlusion (O'Kelly-Marotta grades C or D) at 6 months was the primary endpoint for flow diverter stenting, while residual intra-aneurysmal blood flow during the follow-up was defined as recurrence after coil embolization. In flow diverter stenting cases, relative signal intensity was elevated at 3 months and remained stable. Relative signal intensity 3 months after flow diverter stenting was significantly higher in the satisfactory occlusion group than the non-satisfactory occlusion group (0.99 ± 0.55 vs. 0.51 ± 0.34, p = 0.03) and independently associated with satisfactory occlusion (adjusted odds ratio per 0.1 increase = 1.35, p = 0.01). In coil embolization cases, relative signal intensity was highest at 1 week and decreased linearly. Higher relative signal intensity 1 week after coil embolization was associated with lower recurrence rates (0.60 ± 0.22 vs. 0.41 ± 0.12, p = 0.002) and independently linked to aneurysm recurrence (adjusted odds ratio per 0.1 increase = 0.55, p = 0.004). Relative signal intensity changes on T1-weighted black blood imaging differ between flow diverter stenting and coil embolization. High relative signal intensity 3 months after flow diverter stenting and relative signal intensity 1 week after coil embolization were significantly correlated with favorable outcomes.

OBJECTIVE Aneurysm wall inflammation is associated with lesion instability in unruptured intracranial aneurysms (UIAs). However, most UIAs remain unruptured during lifelong follow-ups because of simultaneous protective remodeling against the inflammatory response. The protective effects of osteoprotegerin (OPG) in intracranial and abdominal aortic aneurysms have been suggested using rodent models; however, the role of this protein in UIAs in humans remains unclear. Herein, the authors examined the relationship between OPG expression and aneurysm wall integrity in intraoperatively resected UIAs by using immunohistochemical and immunofluorescence staining. METHODS Sixteen UIA wall tissue specimens resected between 2017 and 2022 were analyzed. Aneurysm growth was defined as an enlargement > 1 mm or an obvious morphological change over the course of more than 6 months. Three high-power fields were randomly selected from areas expressing high and low levels of OPG within the same aneurysm. To clarify the role of OPG in the human aneurysm wall, the authors compared averaged values for the following pathological features between the 2 OPG expression groups: aneurysm wall thickness, collagen, macrophages, smooth muscle cells, and transforming growth factor beta 1 (TGF-β1). Immunohistochemical staining within the entire tissue area was also analyzed to determine the relationships between OPG expression and different aneurysm growth patterns. Pathological findings were compared between high and low OPG expression levels using the Wilcoxon signed-rank test. RESULTS The heterogeneous expression of OPG was detected in the walls of UIAs. Lesions expressing high OPG levels had thicker aneurysm walls (327 vs 180 μm, p = 0.002) and higher expression levels of TGF-β1 (8.5% vs 5.4%, p = 0.002) than those expressing low OPG levels. The expression of TGF-β1 was colocalized with that of OPG mainly in the tunica media. Furthermore, lesions expressing high OPG levels had larger α-SMA+ areas (25% vs 13%, p = 0.002). Aneurysm growth was observed in 6 of 9 UIAs with available data: whole sac expansion in 4 and secondary aneurysm formation in 2. Among the 6 UIAs with aneurysm growth, OPG expression was relatively higher in the UIAs with an internal elastic lamina than in those without (17% vs 6.9%). CONCLUSIONS Aneurysm wall integrity was associated with OPG expression in the aneurysm wall. Collectively, the study results indicated that OPG is associated with protective remodeling, which may contribute to the retention of aneurysm wall structures.

BACKGROUND/AIM:The characteristics of different breast cancers imaged using dual-energy computed tomography (DECT) are unknown. Furthermore, the differences between DECT and magnetic resonance imaging (MRI) in the ability to assess tumor extent have not been clarified. Therefore, this study aimed to evaluate the effectiveness of DECT iodine maps compared to contrast-enhanced MRI in patients with operable breast cancer.PATIENTS AND METHODS:Clinicopathological data from 858 patients with breast cancer who underwent resection after DECT (100/140 kv) and MRI during 2012-2021 were collected. Tumoral iodine concentration (IC; max/Δ) was analyzed from iodine maps. Factors associated with the ability of iodine maps and MRI to predict tumor extent were analyzed with reference to resected specimens' pathological diagnosis.RESULTS:IC parameters varied according to the tumors' histological types and were correlated with the estrogen receptor, histological grade, and Ki-67 labeling index. In 86.2% of patients with invasive carcinoma with intraductal extension, images and resected specimen mapping were matched. Iodine maps were less accurate than MRI in identifying tumor borders in 9.8% and more accurate in 2.1% of patients. The discrepancies in assessing tumor borders between imaging modalities were associated with the tumor's IC parameters and mammary gland status.CONCLUSION:Differences in assessment between DECT and MRI in operable breast cancer are associated with IC parameters and background parenchymal enhancement. Therefore, evaluating tumor extent using DECT considering these characteristics appears to be a feasible approach.

ObjectivesThe aim of this preplanned primary analysis was to investigate the clinical manifestations of headache to screen for CAD patients with acute onset headache only. BackgroundSpontaneous cervicocerebral artery dissection (CAD) with acute onset headache is not rare in clinical practice; however, it is underdiagnosed. On the other hand, subsequent infarction or subarachnoid hemorrhage mainly occurs within 1 week of headache onset. MethodsBetween April 2017 and January 2022, we conducted a single-center, cross-sectional retrospective study on 197 consecutive referred patients from neurosurgical outpatient clinics with acute onset unusual headache (stronger or longer headache than usual). All patients underwent magnetic resonance imaging to screen for secondary headache and were diagnosed based on the diagnostic protocol. We examined patient background data and the following headache characteristics: distribution, condition at the onset of headache, accompanying vomiting or nausea, worsening headache, and analgesic effects against headache. These factors were analyzed to identify independent diagnostic predictors of CAD. In this study, the rate of missing data was 41% for improvement of headache by analgesia and multiple imputation by chained equations was performed. ResultsA total of 93 patients (46 men and 47 women; mean age: 48 years, range: 25-73 years) were diagnosed with CAD. Univariate logistic regression analysis showed CAD was associated with current smoking, systolic blood pressure >140 mmHg, unilateral headache, worsening headache, and no headache improvement by analgesia. Unilateral, worsening headache and no headache improvement by analgesia remained independent diagnostic predictors in multivariable logistic regression after multiple imputation. No headache improvement by analgesia had the highest sensitivity (86%), while worsening headache had the highest specificity (84%). ConclusionsCAD needs to be considered in patients with unilateral, worsening headache and no headache improvement by analgesia.

BACKGROUND The establishment of a risk stratification method for unruptured intracranial aneurysms (UIAs) remains an interdisciplinary challenge. The present study attempted to identify unstable UIAs using magnetic resonance vessel wall imaging in prospective data sets. Hemodynamic parameters in unstable UIAs were also examined to clarify the mechanisms by which segmented aneurysm wall enhancement (AWE) affects longitudinal morphological changes. METHODS Patients with UIAs who underwent contrast‐enhanced vessel wall imaging between 2017 and 2022 and were followed up for more than 6 months were included. Two readers independently rated AWE patterns (no, focal, and circumferential AWE) on vessel wall imaging and morphological changes on time‐of‐flight magnetic resonance angiography. Computational fluid dynamics studies were performed on unstable UIAs to evaluate the hemodynamic features of evolved or ruptured points in aneurysm walls. RESULTS Aneurysm growth was observed in 13 of 114 UIAs in the present study during a median follow‐up of 34 months. Of the 13 growing UIAs, their AWE patterns were as follows: no AWE in 6 and focal AWE (FAWE) in 7 UIAs. Univariable Cox regression analysis showed that aneurysm size and FAWE were associated with aneurysm growth. On multivariable Cox regression analysis, FAWE (hazard ratio, 4.59 [95% CI, 1.29–16.3]; P=0.019) was independently associated with aneurysm growth. Kaplan–Meier curve revealed significant differences between AWE patterns and UIA growth (P<0.001). Aneurysms ruptured in the 4 UIAs with FAWE during the follow‐up and all rupture points corresponded to nonenhanced lesions in aneurysm walls. Nonenhanced areas had higher wall shear stress than enhanced areas (1.59±1.02 versus 0.53±0.32; P=0.022). CONCLUSION FAWE may be associated with aneurysm growth and rupture during follow‐up. A comprehensive analysis of nonenhanced areas of UIAs with FAWE using vessel wall imaging and computational fluid dynamics provides insights into the mechanisms underlying aneurysm instability.

OBJECTIVE Histopathological studies of aneurysms after coil embolization showed that thrombus formation during the first month after endovascular treatment (EVT) played an important role in the healing process. The authors hypothesized that dedicated T1 -weighted imaging may be used to predict stable aneurysms by visualizing the thrombus status within coil -treated aneurysms. Therefore, this study investigated the relationship between the signal intensity (SI) of the intraaneurysmal sac after coil embolization and aneurysm stability. METHODS The study population included 82 patients with 86 aneurysms who underwent T1-weighted 3D black-blood fast spin-echo (T1 CUBE) imaging within 1 month after coil embolization between 2019 and 2022. The relative SI of a coil-treated aneurysm (RSIcoiled) was calculated as follows: the mean SI of the intraaneurysmal sac/the mean SI of the genu of the corpus callosum. Aneurysms with enlarged remnants on MR angiography (MRA) within 6 months after EVT were defined as recurrence, while a decrease of intraaneurysmal flow on MRA was defined as improved embolization status. Stable aneurysms were defined as improvement or no change in embolization status 6 months after coil embolization. The volume embolization ratio (VER) was calculated as the ratio of the packed coil volume to the aneurysm volume. Differences between stable and recurrent aneurysms were examined. All aneurysms were divided into high and low RSIcoiled groups based on the cutoff value of RSIcoiled, and differences between the two groups were also evaluated. RESULTS Recurrence was confirmed for 26 of 86 aneurysms. A univariable analysis showed that small aneurysms, high VER, and high RSIcoiled were associated with aneurysm stability. In the receiver operating characteristic curve analysis, the optimal cutoff value for RSIcoiled to differentiate stable from recurrent aneurysms was 0.54. The cutoff value for RSIcoiled was selected as 0.50 (sensitivity 0.77, specificity 0.70) because it was half the value of the SI of the corpus callosum and close to the optimal cutoff value. In a multivariable analysis, RSIcoiled > 0.50 (OR 8.1, 95% CI 2.5-27) remained a significant factor for aneurysm stability. The high RSIcoiled group showed a higher rate of an improved embolization status (26% vs 6.1%, p = 0.022) and stable aneurysms (85% vs 15%, p = 0.0002). CONCLUSIONS RSIcoiled was associated with postcoiling aneurysm stability. High RSIcoiled might imply intraaneurysmal thrombus formation associated with the healing process of coil-treated aneurysms.

Objectives: The spontaneous healing of non-hemorrhagic intracranial vertebral artery dissection (VAD) may be associated with the stabilization of intramural hematoma (IMH). We previously suggested that the signal intensity of IMH increases until approximately 2 weeks in VAD with spontaneous healing. We herein investigated the diagnostic accuracy of the signal intensity of IMH at 2 weeks to predict the spontaneous healing of VAD. Methods: From April 2017 to April 2021, we prospectively investigated patients with non-hemorrhagic VAD who underwent vessel wall imaging (VWI). Morphological healing of VAD was evaluated by MR angiography three months after its onset. The relative signal intensity (RSI) of IMH against the posterior cervical muscle on VWI was calculated. Univariate and multivariate analyses were performed on factors associated with the spontaneous healing of VAD among patient baseline data, vascular morphology at the diagnosis, and RSI parameters. Results: Forty-eight patients (23 men and 25 women; mean age: 51 years, range: 34-73 years) with 50 non-hemorrhagic VAD were included in the present study. Spontaneous healing was observed in 28 VAD (56%). RSI two weeks after the onset of VAD (RSI2w) and morphological feature such as the string sign were associated with spontaneous healing, respectively. The multivariate logistic regression analysis identified RSI2w as an independent predictive factor of spontaneous healing (OR: 7.3; 95% CI, 1.9-28, p = 0.004). The cut-off value for RSI2w to predict spontaneous healing was 1.22 (AUC = 0.90, sensitivity: 91%, specificity: 82%). Conclusion: RSI2w predicted the spontaneous healing of non-hemorrhagic VAD 3 months after its onset.

Abstract Background: Contrast-enhanced dual-energy computed tomography produces iodine maps (i-maps) based on tissue iodine concentration (IC). We analyzed the features of i-maps in operable breast cancer. Methods: I-maps made from patients with operable breast cancer were retrospectively reviewed. The mean IC of the whole tumor and visual patterns (sharp/obscure) were analyzed with respect to pathological features. The tumor extent was retrospectively verified with dynamic contrast-enhanced magnetic resonance of mammary gland (MRM) and pathological specimens. Results: The median IC of 858 cases was 4.3 (interquartile range [IQR]: 4.0–5.1) mg/mL. The IC of the luminal A-like subtype of invasive breast cancer was significantly higher than that of the human epidermal growth factor 2 (HER2) and triple-negative (TN) subtypes (luminal A-like: 4.5 [IQR: 4.3–5.5] mg/mL vs. HER2: 3.9 [IQR: 3.5–4.4] mg/mL and TN: 3.8 [IQR: 3.6–4.2] mg/mL; both p < 0.05). The IC was significantly correlated with the histological grade and Ki-67 labeling index. Sharp visual patterns correlated with the estrogen receptor and Ki-67 labeling index, while obscure patterns correlated with the HER2 subtype. I-maps underestimated tumor extent in 84 (9.8%) of the 532 partial resection cases, especially in lobular carcinoma and mucinous carcinoma. Conclusions: The IC and visual patterns correlated with the pathological features of operable breast cancer. Most breast cancers are identifiable on i-maps; however, the adjunction of MRM is preferred for tumors with low IC on i-maps to evaluate tumor extent.

OBJECTIVE Morphological changes in unruptured intracranial aneurysms (UIAs) are an imaging marker of aneurysm instability. Recent studies have indicated the ability of MR vessel wall imaging (VWI) to stratify unstable UIAs based on a correlation with histopathological aneurysm wall inflammation. In the present study the authors investigated the relationships between aneurysm growth patterns and the segmentation of aneurysm wall enhancement (AWE) in VWI. METHODS A total of 120 aneurysms with serial angiography from a follow-up period of at least 2 years (mean 65 months, range 24-215 months) were assessed by VWI. Two readers independently evaluated the patterns of morphological changes (stable, whole sac expansion, and secondary aneurysm formation) and the segmentation of AWE (no, focal, and circumferential AWE). The contrast enhancement ratio of the aneurysm wall versus the pituitary stalk (CRstalk) was calculated for the quantitative assessment of AWE. Statistical analyses were performed to investigate the relationships between AWE patterns and patient baseline profiles, aneurysm characteristics, and morphological modifications. RESULTS Forty-one of 120 UIAs (34%) exhibited aneurysm growth (whole sac expansion in 19 and secondary aneurysm formation in 22). AWE was detected in 35 of 120 UIAs (focal AWE in 25 and circumferential AWE in 10). The maximum diameter of, irregularities in, and morphological modifications in aneurysms were associated with the segmentation of AWE. Focal AWE correlated with secondary aneurysm formation, and circumferential AWE correlated with whole sac expansion. In focal AWE, CRstalk was significantly higher in secondary aneurysm formation than in stable UIAs. UIAs without AWE (categorized as no AWE) correlated with aneurysm stability. CONCLUSIONS The segmentation of AWE was associated with aneurysm growth scenarios and may provide a novel insight into the evaluation of unstable UIAs.

Objective: Unruptured intracranial vertebral artery dissection (VAD) generally heals spontaneously. A chronological evaluation of intramural hematoma (IMH) using Tl-weighted vessel wall imaging (VWI) may provide a more detailed understanding of the pathophysiology of VAD. We herein investigated the relationship between chronological signal changes in IMH on VWI and the spontaneous healing of VAD. Materials and Methods: We retrospectively investigated 26 patients with 27 unruptured VADs who underwent magnetic resonance (MR) imaging more than three times during the follow-up period. Morphological changes were evaluated using MR angiography (MRA). The relative signal intensity (RSI) of IMH against the posterior cervical muscle on T1-weighted VWI was calculated. The ratio of chronological RSI changes was defined as follows: maximum RSI/minimum RSI (RSImax/min). Based on the median value of RSI(ma)(x/min )27 VADs were divided into VADs with and without chronological RSI changes. Statistical analyses were performed to compare clinical and radiological findings between the two groups. Results: Spontaneous healing occurred in 17 out of 27 VADs (63%). The median value of RSImax/min was 1.48. The RSI of VADs with chronological RSI changes (RSImax/min >= 1.48) increased until three weeks after their onset and decreased over time, while that of VADs without chronological RSI changes (RSImax/min < 1.48) showed no change. The frequency of healing was significantly higher in VADs with than without chronological RSI changes (100% vs 23%, p < 0.0001). Conclusions: Chronological signal changes in IMH on T1-weighted VWI have potential as a diagnostic imaging marker of the spontaneous healing of VAD.

Purpose Model-based iterative reconstruction (MBIR) yields higher spatial resolution and a lower image noise than conventional reconstruction methods. We hypothesized that thin-slice MBIR designed for brain CT could improve the detectability of acute ischemic stroke in the middle cerebral artery (MCA) territory. Methods Included were 41 patients with acute ischemic stroke in the MCA territory; they were seen at 4 medical centers. The controls were 39 subjects without acute stroke. Images were reconstructed with hybrid IR and with MBIR designed for brain CT at slice thickness of 2 mm. We measured the image noise in the ventricle and compared the contrast-to-noise ratio (CNR) in the ischemic lesion. We analyzed the ability of reconstructed images to detect ischemic lesions using receiver operating characteristics (ROC) analysis; 8 observers read the routine clinical hybrid IR with 5 mm-thick images, while referring to 2 mm-thick hybrid IR images or MBIR images. Results The image noise was significantly lower on MBIR- than hybrid IR images (1.2 vs. 3.4, p < 0.001). The CNR was significantly higher with MBIR than hybrid IR (6.3 vs. 1.6, p < 0.001). The mean area under the ROC curve was also significantly higher on hybrid IR plus MBIR than hybrid IR (0.55 vs. 0.48, p < 0.036). Sensitivity, specificity, and accuracy were 41.2%, 88.8%, and 65.7%, respectively, for hybrid IR; they were 58.8%, 86.1%, and 72.9%, respectively, for hybrid IR plus MBIR. Conclusion The additional thin-slice MBIR designed for brain CT may improve the detection of acute MCA stroke.

Background and purpose Neutrophil extracellular traps (NETs) exhibit pro-inflammatory and pro-thrombotic properties. However, they have only been reported as important regulators in atherosclerosis, especially in atherothrombosis. We investigated the presence of NETs and plaque instability in patients with carotid artery stenosis. Material and methods A total of 39 consecutive patients with carotid artery stenosis were evaluated. All patients underwent carotid artery stenting (CAS) with dual protection (simultaneous flow reversal + distal filter) and blood aspiration as a method of distal embolism prevention. Local arterial blood was aspirated at the stent site and peptidylarginine deiminase 4 (PAD4), which is essential for the formation of NETs, was measured. The relationships between PAD4 and the patient profile, blood examination and plaque data were investigated. Results The mean value of PAD4 in local arterial blood in CAS was 0.5 ng/ml. Bivariate analysis demonstrated that PAD4 was associated with the neutrophil to lymphocyte ratio (p = 0.007), high-density lipoprotein (p = 0.02), triglycerides to high-density lipoprotein ratio (p = 0.007), ulceration (p = 0.02) and plaque contrast enhancement on T1 black blood imaging (p = 0.03). In multiple linear regression analyses, PAD4 was correlated with the neutrophil to lymphocyte ratio (p = 0.01) and ulceration (p = 0.01, cut-off value: 0.49 odds ratio: 19.3). Conclusions PAD4, representative of the presence of NETs, was high in carotid plaques with unstable features. The neutrophil to lymphocyte ratio in peripheral blood was suggested to be a biomarker of vulnerable plaques. Elucidating the role of NETs may aid in clarifying factors that promote the instability of carotid plaques.

OBJECTIVE:Morphological changes in unruptured intracranial aneurysms (UIAs) are an imaging marker of aneurysm instability. Recent studies have indicated the ability of MR vessel wall imaging (VWI) to stratify unstable UIAs based on a correlation with histopathological aneurysm wall inflammation. In the present study the authors investigated the relationships between aneurysm growth patterns and the segmentation of aneurysm wall enhancement (AWE) in VWI. METHODS:A total of 120 aneurysms with serial angiography from a follow-up period of at least 2 years (mean 65 months, range 24-215 months) were assessed by VWI. Two readers independently evaluated the patterns of morphological changes (stable, whole sac expansion, and secondary aneurysm formation) and the segmentation of AWE (no, focal, and circumferential AWE). The contrast enhancement ratio of the aneurysm wall versus the pituitary stalk (CRstalk) was calculated for the quantitative assessment of AWE. Statistical analyses were performed to investigate the relationships between AWE patterns and patient baseline profiles, aneurysm characteristics, and morphological modifications. RESULTS:Forty-one of 120 UIAs (34%) exhibited aneurysm growth (whole sac expansion in 19 and secondary aneurysm formation in 22). AWE was detected in 35 of 120 UIAs (focal AWE in 25 and circumferential AWE in 10). The maximum diameter of, irregularities in, and morphological modifications in aneurysms were associated with the segmentation of AWE. Focal AWE correlated with secondary aneurysm formation, and circumferential AWE correlated with whole sac expansion. In focal AWE, CRstalk was significantly higher in secondary aneurysm formation than in stable UIAs. UIAs without AWE (categorized as no AWE) correlated with aneurysm stability. CONCLUSIONS:The segmentation of AWE was associated with aneurysm growth scenarios and may provide a novel insight into the evaluation of unstable UIAs.

Background and Purpose: Previous studies suggested that turbulent flow is closely related to plaque vulnerability. Two-dimensional (2D) flow analysis is a novel modality that enables real-time blood flow analysis by picturing particle movement in the contrast medium. We evaluated flow patterns in the carotid plaque to investigate the correlation between blood flow and plaque vulnerability. Material and Methods: A total of 36 consecutive patients with cervical carotid artery stenosis were evaluated. The flow pattern of carotid artery stenosis was evaluated using 2D real-time flow analysis in the digital subtraction angiography (DSA). The flow pattern was classified into either turbulent or laminar flow as vectors. Plaque vulnerability was evaluated on MR plaque imaging. Univariate analysis was performed to assess the correlation between the flow pattern and plaque features. Results: The turbulent pattern was identified in 28 of 36 plaques (77.8%). Turbulence around plaques was significantly associated with Gadolinium enhancement (P = .0004). The maximum degree of stenosis (P = .0005) and concomitant ulceration (P = .02) were significantly associated with the turbulent pattern. There was no relationship between the turbulent pattern and clinical neurological symptoms. Conclusions: In the present study, the majority of carotid plaques exhibited a turbulent flow pattern, which was significantly associated with Gadolinium enhancement on MR plaque imaging and morphologic factors. Thus, real-time flow analysis may clarify the pathophysiology of plaque instability and the formation of ulceration.

BACKGROUND:A detailed understanding of the anatomy of Sylvian veins preoperatively is needed for venous-preserving Sylvian dissection. Better visualization of the venous architecture will facilitate surgical strategies for Sylvian dissection. This study evaluated and compared the image quality of the Sylvian veins and their tributaries using high-resolution cone-beam computed tomography angiography (CBCT-A) and three-dimensional computed tomography angiography (3D-CTA). METHODS:Twenty-four patients who underwent 3D-CTA and CBCT-A as a preoperative simulation for clipping of unruptured intracranial aneurysms were retrospectively reviewed. In comparisons with intraoperative inspections, 3 raters evaluated the image quality of the Sylvian veins by 3D-CTA and CBCT-A with a 5-point scale. Visualization of the Sylvian veins and their tributaries by the 2 imaging modalities was compared using Wilcoxon signed rank test. RESULTS:CBCT-A showed superior image quality to 3D-CTA in evaluations of the discrimination of adjacent superficial Sylvian veins (2.8 ± 0.80 vs. 4.6 ± 0.37, P < 0.0001), adjacent Sylvian veins at the sphenoid wing (3.1 ± 0.71 vs. 4.1 ± 0.56, P = 0.0001), and visualization of the tributaries of the Sylvian veins (2.5 ± 0.70 vs. 4.4 ± 0.37, P < 0.0001). CONCLUSIONS:CBCT-A was superior to 3D-CTA for visualizing the Sylvian veins and their tributaries. CBCT-A will provide important information on the anatomy of the Sylvian veins preoperatively.

Objective: The mechanism involved in progression of unruptured intracranial artery dissection (IAD) is poorly understood. We investigated the relationship between contrast enhancement of dissecting lesions on magnetic resonance vessel wall imaging (MR-VWI) and unruptured IAD progression on the hypothesis that this finding might predict its instability. Methods: A total of 49 unruptured IADs were investigated retrospectively. Three-dimensional T1-weighted fast spin-echo sequences were obtained before and after injection of contrast medium, and the dissecting lesion/pituitary stalk contrast enhancement ratio (CRstalk) was calculated. Unruptured IAD progression was defined as morphological deterioration; progressive dilatation or stenosis. The relations between unruptured IAD progression and potential risk factors were statistically investigated. Results: Morphological deterioration was demonstrated in eleven of 49 unruptured IADs (22 %). The CRstalk value and male predominance was significantly higher in progressed IADs than stable ones (1.0 vs. 0.65; p = 0.0035, 82% vs 37%; p = 0.015, respectively). On stepwise multivariable logistic regression analysis, the CRstalk value was independently associated with unruptured IAD progression with odds ratio of 102.5 (95% CI, 2.59-4059, P=0.0013). The optimal cutoff value of CRstalk to estimate IADs with progression was 0.87 (sensitivity, 0.82; specificity, 0.74). Multimodalic images showed contrast enhancement on VWI corresponded to residual stagnant flow in dissecting lesions. Conclusions: Quantitative analysis of contrast enhancement on VWI could predict instability of unruptured IADs. Contrast enhancement in dissecting lesions would be a clue to understand the mechanism of unruptured IAD progression.

BACKGROUND AND PURPOSE:Early venous filling after endovascular mechanical thrombectomy in acute ischemic stroke (AIS) is a specific finding that may serve as a biomarker for intracranial hemorrhage. However, the pathophysiology of early venous filling and postoperative hemorrhage remains unclear. The aim of this study was to investigate correlation between early venous filling and various factors involving patient demographics and perioperative imaging.METHODS:We prospectively analyzed 35 patients with AIS due to cardioembolism (CE) who underwent successful acute revascularization (TICI ≥2). Ischemic lesions were scored by magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI). Outcomes were assessed using the modified Rankin Scale (mRS) 90 days after stroke onset. Blood flow analysis was evaluated by MRI with arterial spin labeling (ASL). Early venous filling was assessed by digital subtraction angiography (DSA). Univariate analysis was performed to investigate correlations between early venous filling and patient demographics and imaging findings.RESULTS:Early venous filling was observed in 22 of 35 (66%) patients after reperfusion therapy. There was a significant correlation between early venous filling and DWI-ASPECTS (6.2 vs 8.8, p=0.0003), outcome (5 vs 9, p=0.006), hyperperfusion (17 vs 1, p< 0.0001), and hemorrhagic transformation (17 vs 1, p=0.005).CONCLUSIONS:This comprehensive study revealed that early venous filling after reperfusion therapy is associated with postoperative hyperperfusion. Early venous filling may be a marker of the process of hyperperfusion, leading to hemorrhage and an unfavorable outcome. Detection of early venous filling may be an important finding on DSA for subsequent intensive perioperative management.

Background and Purpose: Recent studies have suggested that MR-vessel wall imaging (VWI) or computational fluid dynamics (CFD) could evaluate aneurysm wall features in unruptured intracranial aneurysms (UIAs). The combination of these modalities might be comprehensive and help better understanding of the pathophysiology of aneurysm wall. This study was performed to disclose the relationship between VWI and hemodynamic characteristics evaluated by CFD. Methods: From April 2017 through May 2019, a total of 36 microsurgically-treated UIAs preoperatively underwent VWI and CFD were reviewed. Three-dimensional T1-weighted fast spin-echo sequences were obtained before and after injection of contrast medium, and aneurysm wall enhancement (AWE) was evaluated. CFD was carried out using patient specific geometry models from three-dimensional CT angiography. Morphological variables, intraoperative inspection and hemodynamic parameters were statistically analyzed between enhanced and nonenhanced wall of UIAs. Fourteen UIAs were available for histopathological examination. Results: In morphological variables, maximum diameter and irregularity were associated with AWE (p=0.02, respectively). AWE lesions corresponded to intraoperatively inspected atherosclerotic lesions of UIAs (sensitivity, 0.90; specificity, 0.79). Among hemodynamic parameters, oscillatory velocity index that suggests the directional changes of the flow velocity was significantly higher in UIAs with AWE (p=0.02). Histopathologic studies revealed that wall thickening accompanied by atherosclerosis, neovascularization, and macrophage infiltration corresponded to AWE lesions, while UIAs without AWE demonstrated various histopathological findings such as myointimal hyperplasia or thinning wall with loss of mural cells and wall degeneration. Conclusions: Pathophysiology of AWE could be explained as atherosclerotic changes with inflammation presumably associated with aberrant flow conditions in irregular UIAs. VWI and CFD are complementarily valuable imaging techniques to understand an aneurysm wall pathophysiology.