The evaluation value of intracranial magnetic resonance angiography combined with carotid ultrasound in cerebral infarction.

Objective: To explore the evaluation value of intracranial magnetic resonance angiography (MRA) combined with carotid ultrasound (CU) in patients with cerebral infarction (CI). Methods: A retrospective analysis was conducted on 122 patients with CI who underwent intracranial MRA combined with CU examination in Shengzhou People's Hospital from January 2021 to October 2022. Vascular stenosis rate and CU parameters of patients with different degrees of nerve damage (ND) and size of CI lesion were analyzed. Results: The rate of vascular stenosis and ultrasound parameters significantly varied between patients with different degrees of ND and different sizes of CI lesion. Spearman test showed a significant positive correlation between vascular stenosis, pulsatile index (PI), and resistance index (RI) with the degree of ND and the size of CI lesions in patients. There was a significant negative correlation between peak systolic velocity (PSV) and end-diastolic velocity (EDV) and the degree of ND and the size of CI lesions (P<0.05). Conclusions: Intracranial MRA combined with CU can clarify the vascular stenosis and hemodynamic characteristics of patients with CI, and the combined approach closely correlates with the characteristics of CI, which can be used for disease assessment.

Extraocular muscle volume on time-of-flight magnetic resonance angiography in patients with myasthenia gravis.

INTRODUCTION/AIMS: Despite being a prominent feature of myasthenia gravis (MG), extraocular muscle (EOM) has received little attention in clinical research. The aim of this study was to examine EOM volume in patients with MG and controls using time-of-flight magnetic resonance angiography (TOF-MRA). METHODS: EOM volumes (overall and individual rectus muscles) were calculated using TOF-MRA images and compared between MG patients (including subgroups) and controls. The correlation between EOM volume and disease duration was examined. Predictive equations for the selected parameters were developed using multiple linear regression analysis. RESULTS: EOM volume was lower in MG patients than controls, especially in MG patients with ophthalmoparesis (MG-O). MG-O exhibited a moderate negative correlation between EOM volume and disease duration. Multiple linear regression showed that disease duration and EOM status (ophthalmoparesis or not) account for 48.4% of EOM volume. DISCUSSION: Patients with MG show atrophy of the EOMs, especially those with ophthalmoparesis and long disease duration.

Artificial intelligence-based automatic nidus segmentation of cerebral arteriovenous malformation on time-of-flight magnetic resonance angiography.

OBJECTIVE: Accurate nidus segmentation and quantification have long been challenging but important tasks in the clinical management of Cerebral Arteriovenous Malformation (CAVM). However, there are still dilemmas in nidus segmentation, such as difficulty defining the demarcation of the nidus, observer-dependent variation and time consumption. The aim of this study isto develop an artificial intelligence model to automatically segment the nidus on Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) images. METHODS: A total of 92patients with CAVM who underwent both TOF-MRA and DSA examinations were enrolled. Two neurosurgeonsmanually segmented the nidusonTOF-MRA images,which were regarded as theground-truth reference. AU-Net-basedAImodelwascreatedfor automatic nidus detectionand segmentationonTOF-MRA images. RESULTS: The meannidus volumes of the AI segmentationmodeland the ground truthwere 5.427 ± 4.996 and 4.824 ± 4.567 mL,respectively. The meandifference in the nidus volume between the two groups was0.603 ± 1.514 mL,which wasnot statisticallysignificant (P = 0.693). The DSC,precision and recallofthe testset were 0.754 ± 0.074, 0.713 ± 0.102 and 0.816 ± 0.098, respectively. The linear correlation coefficient of the nidus volume betweenthesetwo groupswas 0.988, p < 0.001. CONCLUSION: The performance of the AI segmentationmodel is moderate consistent with that of manual segmentation. This AI model has great potential in clinical settings, such as preoperative planning, treatment efficacy evaluation, riskstratification and follow-up.

Optimal catheter selection for acute stroke patients with type III aortic arch based on magnetic resonance angiography road mapping of the para-aortic trans-femoral access route before mechanical thrombectomy.

BACKGROUND: Although mechanical thrombectomy for acute ischemic stroke has a high recanalization rate, procedurally challenging lesions remain in approximately 10% of the cases. Type III aortic arches, due to their anatomical configuration, are a fundamental problem impacting this procedure. This study aimed to determine whether optimal catheter selection for type III aortic arches, using magnetic resonance angiography (MRA)-based road mapping of the para-aortic transfemoral access route, reduces the time required for mechanical thrombectomy. METHODS: We retrospectively evaluated 203 consecutive patients who underwent mechanical thrombectomy at multiple centers between April 2018 and July 2022. Twenty-three patients were diagnosed with a type III aortic arch using MRA-based road mapping performed to visualize the para-aortic access route before neuro-interventional procedures. Among the 23 patients with type III aortic arches, 10 received a Simmons-type catheter (initial Simmons group) and 13 received a JB-2-type catheter® (initial JB-2 group) as their first inner catheter. The time required for mechanical thrombectomy was compared between the groups. RESULTS: Compared with the initial JB-2 group, the initial Simmons group exhibited a significantly shorter "puncture-to-recanalization time" (105 vs. 53 min, p = 0.009) and "door-to-recanalization time" (164 vs. 129 min, p = 0.032). CONCLUSIONS: Optimal catheter selection by identifying the aortic arch before mechanical thrombectomy using MRA-based road mapping effectively reduced the mechanical thrombectomy time. This suggests that even in type III aorta cases, appropriate catheter selection may shorten the mechanical thrombectomy time and improve acute ischemic stroke prognosis.

Non-contrast MR angiography: physical principles and clinical applications in chest, abdomen and pelvis imaging.

This review article focuses on the advancements in non-contrast magnetic resonance angiography (NC-MRA) and its increasing importance in body imaging, especially for patients with renal complications, pregnant women, and children. It highlights the relevance of NC-MRA in chest, abdominal, and pelvis imaging and details various bright-blood NC-MRA techniques like cardiac-gated 3D Fast Spin Echo (FSE), balanced Steady-State Free Precession (bSSFP), Arterial Spin Labeling (ASL), and 4D flow methods. The article explains the operational principles of these techniques, their clinical applications, and their advantages over traditional contrast-enhanced methods. Special attention is given to the utility of these techniques in diverse imaging scenarios, including liver, renal, and pelvic imaging. The article underscores the growing importance of NC-MRA in medical diagnostics, offering insights into current practices and potential future developments. This comprehensive review is a valuable resource for radiologists and clinicians, emphasizing NC-MRA's role in enhancing patient care and diagnostic accuracy across various medical conditions.

Ultra-low-field magnetic resonance angiography at 0.05 T: A preliminary study.

We aim to explore the feasibility of head and neck time-of-flight (TOF) magnetic resonance angiography (MRA) at ultra-low-field (ULF). TOF MRA was conducted on a highly simplified 0.05 T MRI scanner with no radiofrequency (RF) and magnetic shielding. A flow-compensated three-dimensional (3D) gradient echo (GRE) sequence with a tilt-optimized nonsaturated excitation RF pulse, and a flow-compensated multislice two-dimensional (2D) GRE sequence, were implemented for cerebral artery and vein imaging, respectively. For carotid artery and jugular vein imaging, flow-compensated 2D GRE sequences were utilized with venous and arterial blood presaturation, respectively. MRA was performed on young healthy subjects. Vessel-to-background contrast was experimentally observed with strong blood inflow effect and background tissue suppression. The large primary cerebral arteries and veins, carotid arteries, jugular veins, and artery bifurcations could be identified in both raw GRE images and maximum intensity projections. The primary brain and neck arteries were found to be reproducible among multiple examination sessions. These preliminary experimental results demonstrated the possibility of artery TOF MRA on low-cost 0.05 T scanners for the first time, despite the extremely low MR signal. We expect to improve the quality of ULF TOF MRA in the near future through sequence development and optimization, ongoing advances in ULF hardware and image formation, and the use of vascular T1 contrast agents.

Evidence for routine brain-to-pelvis imaging and antiplatelet therapy in patients diagnosed with fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a disease of the musculature of arterial walls leading to stenoses, aneurysms, and dissections. The purpose of this report was to summarize the evidence for (1) one-time routine imaging from brain-to-pelvis and (2) lifelong antiplatelet therapy, for example, aspirin, for patients diagnosed with FMD as suggested by an international consensus report from 2019. PubMed was systematically searched, and the evidence providing a basis for the current consensus points, as well as articles published since, were reviewed. In four registries evaluating patients with FMD, the prevalence of multivessel involvement, aneurysms, and dissections was reported to be 43.5%-66.3%, 21.6%-30.6%, and 5.6%-28.1%, respectively. Any antiplatelet drug was used in 72.9% of patients, and aspirin was prescribed in up to 70.2% of patients. Based on the high prevalence of vascular manifestations, their associated morbidity, and the potential for endovascular or surgical intervention, the suggestion of one-time brain-to-pelvis screening with computed tomography angiography or magnetic resonance angiography is well supported. Contrarily, the evidence to support the consensus statement of lifelong antiplatelet therapy to all patients in the absence of contraindications is more uncertain since a beneficial effect has not been demonstrated specifically in patients with fibromuscular dysplasia. Therefore, until the efficacy and safety of primary thromboprophylaxis have been demonstrated in this patient group specifically, it may be equally appropriate to only use antiplatelet agents in patients with a clear indication after individual evaluation according to risk factors for thrombotic and thromboembolic complications.

Marfan and Loeys-Dietz aortic phenotype: A potential tool for diagnosis and management.

Objective: In heritable aortic diseases, different vascular involvement may occur with potential variable implications in aortic dilation/dissection risk. This study aimed to analyze the aortic anatomy of individuals with Marfan syndrome and Loeys-Dietz syndrome to identify possible morphological differences. Methods: Computed tomography and magnetic resonance imaging of the thoracoabdominal aorta from the proximal supra-aortic vessels to the femoral bifurcation level of 114 patients with Marfan and Loeys-Dietz syndromes and 20 matched control subjects were examined. Aortic diameters, areas, length, and tortuosity were measured in different aortic segments using specific vessel analysis software. Results: Patients with Marfan syndrome showed a higher prevalence of ascending aorta and aortic root dilation (P = .011), larger and longer aortic roots (P = .013) with pear-shaped phenotype, larger isthmus/descending aorta diameter ratio (P = .015), and larger suprarenal aorta and iliac arteries. Patients with Loeys-Dietz syndrome showed longer indexed segments and a significantly longer arch (P = .006) with type 2/3 arch prevalence (P = .097). Measurement ratios analysis provided cut-off values (aortic root to ascending aorta length/aortic root diameter, aortic root/sinotubular junction, aortic root/ascending aorta diameter) differentiating patients with Marfan syndrome from patients with Loeys-Dietz syndrome, even in the early stage of the disease. Conclusions: Both syndromes show peculiar anatomic patterns at different aortic levels irrespective of aortic dilation and disease severity. These features may represent the expression of different genetic mutations on aortic development, with a potential impact on prognosis and possibly contributing to better management of the diseases. The systematic adoption of whole body imaging with magnetic resonance or computed tomography should always be considered, because they allow a complete vascular assessment with practical indicators of differential diagnosis.

Basilar artery fenestration in migraine patient.

Basilar artery fenestration should be considered in migraine patients, especially with a cerebrovascular family history, necessitating annual magnetic resonance imaging/angiography (MRI/MRA) monitoring and careful assessment of birth control regimens to mitigate risks.

Development and validation of peritumoral vascular and intratumoral radiomics to predict pathologic complete responses to neoadjuvant chemotherapy in patients with triple-negative breast cancer.

BACKGROUND: To develop and validate a peritumoral vascular and intratumoral radiomics model to improve pretreatment predictions for pathologic complete responses (pCRs) to neoadjuvant chemoradiotherapy (NAC) in patients with triple-negative breast cancer (TNBC). METHODS: A total of 282 TNBC patients (93 in the primary cohort, 113 in the validation cohort, and 76 in The Cancer Imaging Archive [TCIA] cohort) were retrospectively included. The peritumoral vasculature on the maximum intensity projection (MIP) from pretreatment DCE-MRI was segmented by a Hessian matrix-based filter and then edited by a radiologist. Radiomics features were extracted from the tumor and peritumoral vasculature of the MIP images. The LASSO method was used for feature selection, and the k-nearest neighbor (k-NN) classifier was trained and validated to build a predictive model. The diagnostic performance was assessed using the ROC analysis. RESULTS: One hundred of the 282 patient (35.5%) with TNBC achieved pCRs after NAC. In predicting pCRs, the combined peritumoral vascular and intratumoral model (fusion model) yields a maximum AUC of 0.82 (95% confidence interval [CI]: 0.75, 0.88) in the primary cohort, a maximum AUC of 0.67 (95% CI: 0.57, 0.76) in the internal validation cohort, and a maximum AUC of 0.65 (95% CI: 0.52, 0.78) in TCIA cohort. The fusion model showed improved performance over the intratumoral model and the peritumoral vascular model, but not significantly (p > 0.05). CONCLUSION: This study suggested that combined peritumoral vascular and intratumoral radiomics model could provide a non-invasive tool to enable prediction of pCR in TNBC patients treated with NAC.

RNF213 Polymorphisms in Intracranial Artery Dissection.

The ring finger protein 213 gene (RNF213) is involved in several vascular diseases, both intracranial and systemic ones. Some variants are common in the Asian population and are reported as a risk factor for moyamoya disease, intracranial stenosis and intracranial aneurysms. Among intracranial vascular diseases, both moyamoya disease and intracranial artery dissection are more prevalent in the Asian population. We performed a systematic review of the literature, aiming to assess the rate of RNF213 variants in patients with spontaneous intracranial dissections. Four papers were identified, providing data on 53 patients with intracranial artery dissection. The rate of RNF213 variants is 10/53 (18.9%) and it increases to 10/29 (34.5%), excluding patients with vertebral artery dissection. All patients had the RNF213 p.Arg4810Lys variant. RNF213 variants seems to be involved in intracranial dissections in Asian cohorts. The small number of patients, the inclusion of only patients of Asian descent and the small but non-negligible coexistence with moyamoya disease familiarity might be limiting factors, requiring further studies to confirm these preliminary findings and the embryological interpretation.

Incidental Finding of Persistent Trigeminal Artery in a Young Woman: A Case Report.

Persistent trigeminal artery disease is one of the most common types of persistent carotid-vertebrobasilar anastomoses. Usually, it is unilateral, and it can be discovered with a magnetic resonance angiography (MRA), computed tomography angiography (angioCT), or classic angiography exam. It can be associated with non-specific symptoms, such as headaches, or more specific ones, such as III or VI nerve palsy or trigeminal neuralgia, but most of the time it goes undetected, being an incidental finding and not causing any symptoms. On MRA and angioCT, it has the characteristic "tau" sign. We present the case of a young woman who, incidentally, discovered this malformation after undergoing an MRA. She had been experiencing a persistent headache without a known cause, which did not improve despite medication.

Combined duplicate origin and early bifurcated middle cerebral artery diagnosed by magnetic resonance angiography.

PURPOSE: To describe a case of combined duplicate origin and early bifurcated middle cerebral artery (MCA) incidentally diagnosed using magnetic resonance (MR) angiography. METHODS: A 51-year-old woman with an unruptured left MCA aneurysm underwent cranial MR angiography with a 3-Tesla scanner for presurgical evaluation. MR angiography was performed using a standard 3-dimensional time-of-flight technique. RESULTS: An unruptured left MCA aneurysm at the M1-M2 junction was identified. The maximum aneurysm diameter was 9 mm. Two almost equally sized right MCAs arose from the terminal segment of the right internal carotid artery. These two channels soon anastomosed, and the temporal branch arose from the inferior channel. The aneurysm was successfully treated with coil embolization. CONCLUSION: We herein report a case of a combined duplicate origin and early bifurcated MCA. This variation can also be regarded as anastomosis between the main MCA and the duplicated MCA. This variation has been previously reported as segmental duplication of the MCA. This is the third case of this rare MCA variation reported in the relevant English-language literature. The term "segmental duplication" may be confused with duplicate origin of the MCA, in which only one artery is located distal to the fusion.

The Spectrum of Intracranial Arteriopathies and Ischemic Strokes in Pediatric Tubercular Meningitis: A Tricentric Study From Eastern India.

INTRODUCTION: Addressing the need to uniformly classify arteriopathies among patients with arterial ischemic stroke (AIS) due to tubercular meningitis (TBM), we used the Childhood AIS Standardised Classification and Diagnostic Evaluation (CASCADE) criteria. METHODS: This tri-centric prospective study included children aged 0.5-12 years with TBM and AIS. Magnetic resonance angiographies (MRAs) were done during admission and repeated 3 and 12 months after discharge. Arteriopathies were classified according to the primary CASCADE criteria. We used the modified Pediatric Alberta Stroke Programme Early Computed Tomography Score as an ordinal measure of infarct volume. The severity of arteriopathies was graded using the focal cerebral arteriopathy severity score (FCASS). The final outcomes were measured at the 12-month follow-up visit using the Pediatric Stroke Outcome Measure (PSOM). RESULTS: Out of 55 patients, 64% had MRA-evidenced arteriopathies and 84% had multiple infarcts. The middle cerebral (46%) and internal carotid arteries (22%) were most commonly affected. The basal ganglia (70%) and the cerebral cortex (61%) were most commonly infarcted. CASCADE categories included 3b (40%), 1d (38%), 2b (16%), 2c (5%), progressive (32%), and stable (44%) arteriopathies. Younger age, hypertrophic pachymeningitis, cortical infarcts, recurrent strokes, progressive arteriopathies, EEG abnormalities, and mortality were significantly higher among patients with MRA-proven arteriopathies. Patients with progressive arteriopathies had a significantly higher prevalence of hypertrophic pachymeningitis, cortical infarcts, and recurrent strokes. FCASS correlated positively with outcomes measured by the Pediatric Stroke Outcome Measure and modified Pediatric Alberta Stroke Programme Early Computed Tomography Score. CONCLUSION: The CASCADE classification clarified the arteriopathy patterns, enabling us to correlate them with the characteristics of the infarcts. FCASS is useful to grade the arteriopathy severity and progression in TBM.

Time-of-flight MRA of intracranial vessels at 7 T.

BACKGROUND: Three-dimensional time-of-flight magnetic resonance angiography (TOF-MRA) is a largely adopted non-invasive technique for assessing cerebrovascular diseases. We aimed to optimize the 7-T TOF-MRA acquisition protocol, confirm that it outperforms conventional 3-T TOF-MRA, and compare 7-T TOF-MRA with digital subtraction angiography (DSA) in patients with different vascular pathologies. METHODS: Seven-tesla TOF-MRA sequences with different spatial resolutions acquired in four healthy subjects were compared with 3-T TOF-MRA for signal-to-noise and contrast-to-noise ratios as well as using a qualitative scale for vessel visibility and the quantitative Canny algorithm. Four patients with cerebrovascular disease (primary arteritis of the central nervous system, saccular aneurism, arteriovenous malformation, and dural arteriovenous fistula) underwent optimized 7-T TOF-MRA and DSA as reference. Images were compared visually and using the complex-wavelet structural similarity index. RESULTS: Contrast-to-noise ratio was higher at 7 T (4.5 ± 0.8 (mean ± standard deviation)) than at 3 T (2.7 ± 0.9). The mean quality score for all intracranial vessels was higher at 7 T (2.89) than at 3 T (2.28). Angiogram quality demonstrated a better vessel border detection at 7 T than at 3 T (44,166 versus 28,720 pixels). Of 32 parameters used for diagnosing cerebrovascular diseases on DSA, 27 (84%) were detected on 7-T TOF-MRA; the similarity index ranged from 0.52 (dural arteriovenous fistula) to 0.90 (saccular aneurysm). CONCLUSIONS: Seven-tesla TOF-MRA outperformed conventional 3-T TOF-MRA in evaluating intracranial vessels and exhibited an excellent image quality when compared to DSA. Seven-tesla TOF-MRA might improve the non-invasive diagnostic approach to several cerebrovascular diseases. RELEVANCE STATEMENT: An optimized TOF-MRA sequence at 7 T outperforms 3-T TOF-MRA, opening perspectives to its clinical use for noninvasive diagnosis of paradigmatic pathologies of intracranial vessels. KEY POINTS: • An optimized 7-T TOF-MRA protocol was selected for comparison with clinical 3-T TOF-MRA for assessing intracranial vessels. • Seven-tesla TOF-MRA outperformed 3-T TOF-MRA in both quantitative and qualitative evaluation. • Seven-tesla TOF-MRA is comparable to DSA for the diagnosis and characterization of intracranial vascular pathologies.

Occipital artery to vertebral artery bypass for treatment of bilateral vertebral artery occlusion with QMRA as an adjunct to diagnostic assessment.

PURPOSE: Stroke, the second leading cause of death globally, often involves ischemia in the vertebrobasilar territory. This condition is underexplored, despite significant morbidity and mortality risks. The purpose of this study is to present a case of occipital artery to V3 segment vertebral artery bypass, emphasizing the role of quantitative magnetic resonance angiography (qMRA) in assessing flow and guiding surgical intervention. METHODS: A 66-year-old man with bilateral vertebral artery occlusion presented acute symptoms. qMRA was employed to evaluate flow dynamics and determine the feasibility of a flow augmentation bypass surgery. The occipital artery to left vertebral artery bypass (OA-to-VA) was performed, utilizing an inverted hockey-stick incision and an antegrade inside-out technique. The patency of the bypass was confirmed using both Doppler probe and Indocyanine green. RESULTS: Postoperative assessments, including computed tomography angiography (CTA) and qMRA, demonstrated the patency of the bypass with improved flow in the basilar artery and left vertebral artery. The patient's condition remained stable postoperatively, with residual peripheral palsy of the left facial nerve. CONCLUSION: In conclusion, the presented case illustrates the efficacy of the OA-to-VA bypass in addressing symptomatic bilateral vertebral artery occlusion. The study underscores the pivotal role of qMRA in pre- and postoperative assessments, providing noninvasive flow quantification for diagnostic considerations and long-term follow-up in patients with vertebrobasilar insufficiency.

Deep learning-based platform performs high detection sensitivity of intracranial aneurysms in 3D brain TOF-MRA: An external clinical validation study.

PURPOSE: To evaluate the diagnostic efficacy of a developed artificial intelligence (AI) platform incorporating deep learning algorithms for the automated detection of intracranial aneurysms in time-of-flight (TOF) magnetic resonance angiography (MRA). METHOD: This retrospective study encompassed 3D TOF MRA images acquired between January 2023 and June 2023, aiming to validate the presence of intracranial aneurysms via our developed AI platform. The manual segmentation results by experienced neuroradiologists served as the "gold standard". Following annotation of MRA images by neuroradiologists using InferScholar software, the AI platform conducted automatic segmentation of intracranial aneurysms. Various metrics including accuracy (ACC), balanced ACC, area under the curve (AUC), sensitivity (SE), specificity (SP), F1 score, Brier Score, and Net Benefit were utilized to evaluate the generalization of AI platform. Comparison of intracranial aneurysm identification performance was conducted between the AI platform and six radiologists with experience ranging from 3 to 12 years in interpreting MR images. Additionally, a comparative analysis was carried out between radiologists' detection performance based on independent visual diagnosis and AI-assisted diagnosis. Subgroup analyses were also performed based on the size and location of the aneurysms to explore factors impacting aneurysm detectability. RESULTS: 510 patients were enrolled including 215 patients (42.16 %) with intracranial aneurysms and 295 patients (57.84 %) without aneurysms. Compared with six radiologists, the AI platform showed competitive discrimination power (AUC, 0.96), acceptable calibration (Brier Score loss, 0.08), and clinical utility (Net Benefit, 86.96 %). The AI platform demonstrated superior performance in detecting aneurysms with an overall SE, SP, ACC, balanced ACC, and F1 score of 91.63 %, 92.20 %, 91.96 %, 91.92 %, and 90.57 % respectively, outperforming the detectability of the two resident radiologists. For subgroup analysis based on aneurysm size and location, we observed that the SE of the AI platform for identifying tiny (diameter＜3mm), small (3 mm ≤ diameter＜5mm), medium (5 mm ≤ diameter＜7mm) and large aneurysms (diameter ≥ 7 mm) was 87.80 %, 93.14 %, 95.45 %, and 100 %, respectively. Furthermore, the SE for detecting aneurysms in the anterior circulation was higher than that in the posterior circulation. Utilizing the AI assistance, six radiologists (i.e., two residents, two attendings and two professors) achieved statistically significant improvements in mean SE (residents: 71.40 % vs. 88.37 %; attendings: 82.79 % vs. 93.26 %; professors: 90.07 % vs. 97.44 %; P < 0.05) and ACC (residents: 85.29 % vs. 94.12 %; attendings: 91.76 % vs. 97.06 %; professors: 95.29 % vs. 98.82 %; P < 0.05) while no statistically significant change was observed in SP. Overall, radiologists' mean SE increased by 11.40 %, mean SP increased by 1.86 %, and mean ACC increased by 5.88 %, mean balanced ACC promoted by 6.63 %, mean F1 score grew by 7.89 %, and Net Benefit rose by 12.52 %, with a concurrent decrease in mean Brier score declined by 0.06. CONCLUSIONS: The deep learning algorithms implemented in the AI platform effectively detected intracranial aneurysms on TOF-MRA and notably enhanced the diagnostic capabilities of radiologists. This indicates that the AI-based auxiliary diagnosis model can provide dependable and precise prediction to improve the diagnostic capacity of radiologists.

Triplicated middle cerebral arteries (duplicated and ipsilateral accessory) associated with triplicated anterior cerebral arteries (accessory) diagnosed by magnetic resonance angiography.

PURPOSE: To describe a case of duplicated middle cerebral artery (MCA) combined with ipsilateral accessory MCA, forming a triplicated MCA, associated with the accessory anterior cerebral artery (ACA), forming a triplicated A2 segment of the ACA detected incidentally on magnetic resonance (MR) angiography. METHODS: A 70-year-old woman with internal carotid artery (ICA) stenosis at the origin, which was detected by ultrasound, underwent cranial MR imaging and MR angiography of the intracranial region for an evaluation of brain and cerebral arterial lesions. The MR machine was a 3-Tesla scanner. MR angiography was performed using a standard 3-dimensional time-of-flight technique. RESULTS: Multiple ischemic white matter lesions are observed. No significant stenotic lesions were observed in intracranial arteries. The right duplicated MCA was originated from right distal ICA. And main MCA was originated from right ICA bifurcation. Right accessory MCA was arisen from the A2 segment of the right ACA. Thus, the right MCA was triplicated. There was also an accessory ACA forming a triplicated ACA at its A2 segment. These findings were clearly identified on partial volume-rendering (VR) images. CONCLUSION: We herein report a case of triplicated MCA associated with triplicated ACA. MCA variations are relatively rare, and this is the third case of triplicated MCA reported in relevant English-language literature. To identify multiple cerebral arterial variations, creating partial VR images using MR angiographic source images is useful.

Spiral time-of-flight magnetic resonance angiography for intracranial vascular imaging: performance compared to conventional Cartesian angiogram.

Background: Computed tomography angiography (CTA) and digital subtraction angiography (DSA) usually raise the risk of potential malignancies with cumulative radiation doses. Current time-of-flight magnetic resonance angiography (TOF-MRA) (dubbed as cTOF), which is based on Cartesian sampling mode, may show limited diagnostic conspicuity at sinuous or branching regions. It is also prone to relatively high false positive diagnoses and undesirable display of distal intracranial vessels. This study aimed to use spiral TOF-MRA (sTOF) as a noninvasive alternative to explore possible improvement, such that the application of magnetic resonance angiography (MRA) can be extended to facilitate clinical examination or cerebrovascular disease diagnosis and follow-up studies. Methods: Initially, 37 patients with symptoms of dizziness or transient ischemic attack were consecutively recruited for suspected intracranial vascular disease examination from Zhongshan Hospital of Xiamen University between July 2020 and April 2021 in this cross-sectional prospective study. After excluding 1 patient with severe scanning artifacts, 1 patient whose scanning scope did not meet the requirement, and 1 patient with confounding tumor lesions, a total of 34 participants were included according to the inclusion and exclusion criteria. Each participant underwent intracranial vascular imaging with both sTOF and cTOF sequences on a 3.0 T MR scanner with a conventional head-neck coil of 16 channels. Contrast CTA or DSA was also performed for 15 patients showing pathology. Qualitative comparisons in terms of image quality and diagnostic efficacy ratings, quantitative comparisons in terms of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel length, and sharpness were evaluated. Pair-wise Wilcoxon test was performed to evaluate the imaging quality derived from cTOF and sTOF acquisitions and weighted Cohen's Kappa was conducted to assess the rating consistency between different physicians. Results: Compared to cTOF, sTOF showed better performance with fewer artifacts. It can effectively alleviate false positives of normal vessels being misdiagnosed as aneurysm or stenosis. Improved conspicuity was observed in cerebral distal regions with more clearly identifiable vasculature at finer scales. Quantitative comparisons in selected regions revealed significant improvement of sTOF in SNR (P<0.01 or P<0.001), CNR (P<0.001), vessel length (P<0.001), and sharpness (P<0.001) as compared to cTOF. Besides, sTOF can depict details of M1 and M2 segments of middle cerebral artery (MCA) at metallic implant region, showing its resistance to magnetic susceptibility. Conclusions: The sTOF shows higher imaging quality and lesion detectability with reduced artifacts and false positives, representing a potentially feasible surrogate in intracranial vascular imaging for future clinic routines.