Magnetic Resonance Imaging Angiography Research Articles

Vasospastic angina following COVID-19 vaccine-related myocarditis: an underlying cause of chest pain.

We present a 13-year-old boy who had recurrent chest pain with elevated cardiac enzymes and abnormal ST segments in electrocardiogram 36 hours after the second dose of BNT162b2 vaccination. Cardiac MRI and coronary angiography with acetylcholine provocation confirmed myocarditis and vasospastic angina, respectively. Coronary vasospasm may play a pivotal role in the chest pain in COVID-19 vaccine-related myocarditis.

Moyamoya syndrome in Schimke immuno-osseous dysplasia

Introduction. Schimke immuno-osseous dysplasia (SIOD) is a rare autosomal recessive multisystem disorder associated with biallelic mutations of the SMAR-CAL1 gene. Vascular central nervous system complications in the form of Moyamoya syndrome (MMS) have been reported as a comorbidity in nearly half of the patients clinically presenting with severe migraine-like headaches, transient ischemic attacks (TIA), and ischemic or hemorrhagic infarctions. We present an illustrative case of an infantile form of SIOD with MMS, with a review of the latest diagnostic possibilities, as well as current diagnostic and therapeutic dilemmas in managing SIOD. Case report. We present a female patient with the infantile form of SIOD. The proband was born small for gestational age in the 34th gestation week with characteristic dysmorphic features. Genetic testing found a biallelic, nonsense mutation c.2542G>T in the SMARCAL1 gene. The patient presented early with TIA, seizures, and recurrent ischemic strokes. Magnetic resonance imaging (MRI) confirmed the presence of progressive brain atrophy with bilateral occlusion/stenosis of middle cerebral artery and anterior cerebral artery and a smoke-like collateral vessel appearance consistent with the MMS. At the age of 5 years and 9 months, the patient developed a high fever and cough with unknown cause, with a low erythrocyte and white blood cell count during four weeks, with a poor therapeutic response to antibiotics, transfusion of red blood cells, and granulocyte growth factor. She later died. Conclusion. Patients with SIOD may present progressive cerebral vascular changes and clinical neurologic deterioration early in the course of the disease. In such patients, early diagnosis and preventive revascularization surgery are of paramount importance. In diagnosing MMS, MRI angiography can be an appropriate substitute for standard invasive cerebral angiography.

Non-contrast magnetic resonance angiography for systemic artery evaluation in Kawasaki disease.

Kawasaki disease (KD) is a systemic vasculitis; systemic arteries other than the coronary arteries should therefore also be evaluated. This study investigated the feasibility of evaluating coronary aneurysms, systemic artery aneurysms (SAAs), and cerebrovascular diseases in patients with KD using non-contrast magnetic resonance angiography (NC-MRA). Coronary artery protocols, including coronary magnetic resonance angiography (MRA) and vessel wall imaging, were performed in 57 examinations of 28 patients. Systemic artery protocol, including SAA scans and head MRA, along with coronary artery protocol, were performed in 42 examinations of 42 patients. The image quality of the SAAs was evaluated on a 4-point scale. Examination time and sedation dosage were compared between the protocols. The presence of SAAs and cerebrovascular disease was also evaluated. The image quality score of SAAs was 4 (interquartile range [IQR]: 4-4) for the aorta, 4 (IQR: 3-4) for the subclavian artery, 4 (IQR: 3-4) for the renal artery, and 3 (IQR: 3-4) for the iliac artery. No differences were found between examination time (47.0 [IQR: 43.0-61.0] min vs. 51.0 [IQR: 45.0-60.0] min, p = 0.48) and sedative dose (4.63 [IQR: 3.93-5.79] mg/kg vs. 4.21 [IQR: 3.56-5.71] mg/kg, p = 0.37) between the protocols. Systemic artery protocol detected SAAs in three patients (7.1%), and cerebrovascular disease was not detected. Evaluating the coronary and systemic arteries in patients with KD using NC-MRA on a single examination was possible without compromising examination time or sedation dose. The systemic artery protocol was useful in finding SAAs.

Model utility of a deep learning-based segmentation is not Dice coefficient dependent: A case study in volumetric brain blood vessel segmentation

Cerebrovascular disease is one of the world's leading causes of death. Blood vessel segmentation is a primary stage in diagnosing. Although a few deep neural networks have been suggested to automate volumetric brain blood vessel segmentation, few studies have considered the relevance of the evaluation metrics to diagnosing cerebrovascular disease due to the complicated nature of this task. This study aimed to understand if brain vasculature segmentation using a convolutional neural network (CNN) could meet radiologists' requirements for disease diagnosis. We employed a deeply supervised attention-gated 3D U-Net trained based on the Focal Tversky loss function to extract brain vasculatures from volumetric magnetic resonance angiography (MRA) images. Here we show that our training procedure led to biologically relevant results despite not scoring well using the Dice score, a common metric for algorithm evaluation. We achieved Dice (±SD) = 0.71 ± 0.02 and two radiologists confirmed and validated that our method successfully captured the major blood vessel branches of the circle of Willis (CoW) having biological importance, including internal carotid artery (ICA), middle cerebral artery (MCA), anterior cerebral artery (ACA), and posterior cerebral artery (PCA). Adding radiologists' expert opinions, we could fill this gap that using only the current common evaluation metrics, such as the Dice coefficient, is not enough for brain vessel segmentation assessment. These results suggest the additional value for computational approaches that are designed with end-user stakeholders in mind.

Verifying the Accuracy of Hemodynamic Analysis Using High Spatial Resolution 3D Phase-contrast MR Imaging on a 7T MR System: Comparison with a 3T System.

Hemodynamics is important in the initiation, growth, and rupture of intracranial aneurysms. Since intracranial aneurysms are small, a high-field MR system with high spatial resolution and high SNR is desirable for this hemodynamic analysis. The purpose of this study was to investigate whether the accuracy of MR fluid dynamic (MRFD) results based on 3D phase-contrast MR (3D PC MR, non-electrocardiogram[ECG]-gated 4D Flow MRI) data from a human cerebrovascular phantom and human healthy subjects obtained by a 7T MR system was superior to those by a 3T MR system. 3D PC MR and 3D time of flight MR angiography (3D TOF MRA) imaging were performed on a 3T MR system and a 7T MR system for a human cerebrovascular phantom and 10 healthy human subjects, and MRFD analysis was performed using these data. The MRFD results from each MR system were then compared with the following items based on the computational fluid dynamics (CFD) results: 3D velocity vector field; correlation coefficient (R), angular similarity index (ASI), and magnitude similarity index (MSI) of blood flow velocity vectors. In the MRFD results of 3D velocity vectors of the cerebrovascular phantom, noise-like vectors were observed near the vascular wall on the 3T MR system, but no noise was observed on the 7T MR system, showing results similar to those of CFD. In the MRFD results of the cerebrovascular phantom and healthy subjects, the correlation coefficients R, ASI, and MSI of the 7T MR system were higher than those of the 3T MR system, and ASI and MSI of healthy human subjects were significantly different between the two systems. The accuracy of high spatial resolution MRFD using the 7T MR system exceeded that of the 3T MR system.

A Case report succeeding Idiopathic Oculomotor Nerve Palsy

Oculomotor palsy is a condition characterized by Ptosis, Anisocoria, ocular pain, diplopia and defective eye movements. Management mainly includes corticosteroids and surgical correction. In Ayurveda, nerve palsies are categorized as ‘Vataja diseases’ but in palsies of cranial nerves, Pitta dosha is also associated along with Vata pertaining to the fact that brain is the site of Sadhaka Pitta. Thus, Oculomotor nerve palsy (3rd cranial nerve) considered to be Vata-pittaja ailment. The present case report is of 40 years male patient presented with OD (Oculus Dexter) oculomotor cranial nerve palsy with drooping eye lid and diplopia after intense pain on right side of head. There was no associated history of hypertension, diabetes or hyperlipidemia. Oculomotor nerve palsy was diagnosed as idiopathic after thorough assessment, examination, laboratory investigations and contrast MRI and MR angiography of brain, orbits. Patient was managed by Ayurvedic treatment specially Vata pitta pacifying medicines for one month and got complete remission. It is the one the known case in which complete resolution of this disease has been seen in one month only by Ayurvedic treatment. A case series or pilot studies may further strengthen above case report and open new treatment arena for such challenging cases. This case report can also be used to formulate hypothesis for the management of cranial nerve palsies from an ayurvedic perspective.

Rapid MR Angiography Using 3D Gradient-echo Imaging and the Two-point Dixon Method to Evaluate Carotid Plaque.

Liver acquisition with volume acceleration-flex (LAVA-Flex) acquires out-of-phase and in-phase echo images and automatically generates water-only and fat-only images from one single acquisition. The scan time of carotid MR angiography (MRA) using LAVA-Flex (LAVA MRA) is about one-fifth that of conventional time-of-flight MRA (cTOF MRA). We aimed to investigate whether LAVA MRA could provide useful information for the diagnosis of carotid plaque by utilizing the ability to acquire multiple sequences simultaneously. Comparing LAVA MRA and cTOF MRA images for carotid plaque, low-intensity plaques were more clearly identified in the in-phase images, and high-intensity plaques were more clearly identified in the water-only or out-of-phase images. None of the plaques exhibited superior visualization with the cTOF sequence. We concluded that LAVA MRA can provide more useful information on plaque evaluation using multiple sequences than cTOF MRA.

Persistent Primitive Trigeminal Artery – A Rare Vessel

Primitive carotido vertebral anastomosis is a well-recognized entity. During intrauterine development, craniovertebral blood circulation is characterized by temporary connections between the primitive internal carotid and dorsal longitudinal neural arteries. With normal development, they regress in the prenatal period. The most common of these is a persistent primitive trigeminal artery (PPTA) We report the case of a young male patient with intracranial bleed in the left capsuloganglionic region who was subsequently found to have a persistent primitive trigeminal artery on Magnetic Resonance Imaging Angiography.

MRI visualization of aortic recoarctation in the long-term period after surgery (case report)

Case study. Aortic coarctation refers to well-known and well-studied congenital malformations of the cardiovascular system. The success of cardiovascular surgery significantly increased the survival rate of patients, but, unfortunately, did not reduce the risks of serious cardiovascular complications in the long-term postoperative period. One of the significant complications remains recoarctation – repeated narrowing in the area of surgery, which can initiate other complications.The purpose of the study: to present the features of blood flow in the aorta in a patient with aortic coarctation in the long-term postoperative period on the clinical example of a complex MR examination.Material and methods. A 12-year-old patient, at the age of 6, she underwent balloon angioplasty of aortic coarctation. Echocardiographic data revealed a residual gradient at the isthmus of the aorta and expansion of the descending aorta. To clarify the diagnosis, MRI angiography of the heart was performed with intravenous contrast and the use of a cardiopackage for 4D flow analysis (4D flow).Results and discussion. According to the MRI study, a narrowing of the distal aortic arch with aortic dilation after the departure of the left subclavian artery was revealed, which is confirmed by the obtained absolute values of blood flow indicators. MR-angiography of the aortic arch made it possible to visually determine the “gothic” shape of the aortic arch and present 3D reconstructions. 4D flow maps showed acceleration of blood flow to the systole in the area of aortic narrowing, additional vortex flow below the area of aortic narrowing and spiral flow in the descending aorta, which persisted throughout the diastole.One explanation for the abnormal spiral flow in the descending thoracic aorta may be the presence of a “gothic” aortic arch. Also, residual hypoplasia of the aortic arch and narrowing of the isthmus are the leading parameters affecting the pathophysiology of changes in blood pressure during exercise.Conclusion. The 4D-flow MR package in vivo makes it possible to study the flow geometry and blood flow parameters in detail, to obtain a detailed picture of the aortic condition, which gives potential advantages in a comprehensive examination of patients with aortic coarctation under dynamic observation.

High relative amount of nodular calcification in femoral plaques is associated with milder lower extremity arterial disease

BackgroundClinical implications of different types of vascular calcification are poorly understood. The two most abundant forms of calcification, nodular and sheet calcification, have not been quantitatively analyzed in relation to the clinical presentation of lower extremity arterial disease (LEAD).MethodsThe study analyzed 51 femoral artery plaques collected during femoral endarterectomy, characterized by the presence of > 90% stenosis. Comprehensive clinical data was obtained from patient records, including magnetic resonance angiography (MRA) images, toe pressure and ankle brachial index measurements and laboratory values. The plaques were longitudinally sectioned, stained with Hematoxylin and Eosin and digitized in a deep learning platform for quantification of the relative area of nodular and sheet calcification to the plaque section area. A deep learning artificial intelligence algorithm was designed and independently validated to reliably quantify nodular calcification and sheet calcification. Vessel measurements and quantity of each calcification category was compared to the risk factors and clinical presentation.ResultsOn average, > 90% stenosed vessels contained 22.4 ± 12.3% of nodular and 14.5 ± 11.8% of sheet calcification. Nodular calcification area proportion in lesions with > 90% stenosis is associated with reduced risk of critically low toe pressure (< 30 mmHg) (OR = 0.910, 95% CI = 0.835–0.992, p < 0.05), severely lowered ankle brachial index (< 0.4) (OR = 0.912, 95% CI = 0.84–0.986, p < 0.05), and semi-urgent operation (OR = 0.882, 95% CI = 0.797–0.976, p < 0.05). Sheet calcification did not show any significant association.ConclusionsLarge amount of nodular calcification is associated with less severe LEAD. Patients with nodular calcification may have better flow reserves despite local obstruction.

Gadofosveset-Trinatrium-Enhanced MR Angiography and MR Venography in the Diagnosis of Venous Thromboembolic Disease: A Single-Center Cohort Study.

The aim of this single-center combined prospective/retrospective cohort study was to analyze Gadolinium (Gd)-enhanced MRA (magnetic resonance angiography) and MRV (MR venography) for the diagnosis of pulmonary artery embolism and deep venous thrombosis. The gold standard methods result in major exposure to radiation and a high amount of nephrotoxic iodinated contrast media. This is the first larger contrast-enhanced MR imaging study of acute and chronic venous thromboembolic disease of various stages. We prospectively examined 88 patients presenting clinical signs of deep vein thrombosis and/or pulmonary artery embolism. A single-session, one-stop shop Gd-enhanced MRA/MRV at 1.5 Tesla, using gradient echo sequences with very short repetition and echo times as well as low flip angles with subtraction and three-dimensional reconstruction, was performed. A diagnosis was made with the consensus of two experienced radiologists. We observed excellent MRA image quality in 87% and even higher diagnostic image quality of MRV in 90% of our examinations. Pulmonary artery embolism occurred with deep vein thrombosis in 22%. Gd-enhanced MRA/MRV provided excellent image quality for the diagnosis of venous thromboembolic disease in the majority of cases. It may be particularly useful to plan and follow-up filter implantation and retrieval in the inferior caval vein.

Chronic headache and migraine in pregnancy

The clinical picture of headaches in pregnancy is a therapeutic challenge through the effects of drugs on the mother and fetus. Headache during pregnancy can be primary or secondary to a severe condition that can endanger the patient’s life (stroke, cerebral venous thrombosis, eclampsia, brain tumors, choriocarcinoma, subarachnoid hemorrhage). Differentiating the type of headache requires a series of investigations: electroencephalography, vascular ultrasound, brain MRI and MRI angiography, and contrast ophthalmoscopy. The evolution without treatment of this pain causes depression, stress, sleep deficit, and malnutrition with disastrous consequences for the mother and fetus. Therapeutic management for the treatment of headaches should be initially non-pharmacological, and low-risk fetal drugs should be used in the absence of a response.

Diagnostic test accuracy of imaging modalities for adults with acute pulmonary embolism: A systematic review and meta-analysis

ObjectivesThis systematic review and meta-analysis aimed to evaluate the current literature on diagnostic test accuracy (DTA) of imaging modalities for adults with acute pulmonary embolism (APE). BackgroundMedical imaging plays an integral role in evaluating and managing those with APE. Guidance for imaging modality use for APE diagnosis varies due to a lack of clinical standardisation. Despite this, CTPA remains the first-line imaging modality used by clinicians. MethodsA literature search of PubMed, EMBASE, Trove and Mednar databases (2012-2020; English language) was performed. Studies assessing the DTA of imaging modalities for APE diagnosis were included. DTA studies methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2 tool). Results of eligible studies were pooled using random or fixed effects modelling the calculate the pooled DTA of explored imaging modalities for APE. The Higgins I2 test were performed to assess between study heterogeneity. Results10 Studies, involving 998 participants, were enrolled and pooled using the random effects model. Of the explored modalities, magnetic resonance imaging (MRI), specifically pulmonary MRI and magnetic resonance pulmonary angiography (MRPA) exhibited the highest pooled DTA. Sensitivity, specificity, negative likelihood ratio, positive likelihood ratio and diagnostic odds ratio for MRPA were 0.952 (95% CI, 0.881 to 0.987), 0.857 (95% CI, 0.637 to 0.97), 5.631 (95% CI, 2.163 to 14.659), 0.06 (95% CI, 0.007 to 0.537) and 80.310 (95% CI, 15.607 to 413.25) respectively. Based on the QUADAS-2 criteria, most studies presented low to moderate risk of bias and concern regarding applicability. ConclusionThe explored ultrasound and MRI protocols which exhibit a lower radiation burden when compared to the current gold standard computed tomography pulmonary angiography (CTPA), have acceptable diagnostic accuracy for APE and can be useful in certain situations.

Abstract 15654: Mitral Valve Strands in a Patient With Cerebellar Infarcts

Case Description: A 56-year-old man with a history of hypertension, diabetes, hyperlipidemia, and ischemic stroke 2 years ago presented with left-sided weakness, unsteady gait, and vomiting for 12 hours. The patient was vitally stable, and examination revealed dysarthria, left ataxic hemiparesis, and chronic right facial droop. Magnetic Resonance Imaging (MRI) brain showed an evolving acute infarct in the left superior cerebellum with trace petechial hemorrhage, chronic small right posterior inferior cerebellar infarct, and chronic bilateral cerebellar lacunar infarcts. The patient had an implantable loop recorder placed after his previous stroke, which did not show any arrhythmias on interrogation. MRI Angiography of the head/neck did not show large vessel occlusions. Transesophageal echocardiography (TEE) ruled out a patent foramen ovale but did reveal multiple filamentous structures (&lt;5mm in size) on the atrial side of the posterior mitral valve leaflet (figure 1); these were consistent with fibrin valve strands, or Lambl’s excrescences (LE). Anticoagulation therapy was started, and surgical excision was recommended. Discussion: LE are rare fibrous/filamentous valvular strands caused by wear and tear at the closure lines of left-sided heart valves. LE can be associated with thromboembolic strokes and acute coronary syndromes; however, it can also be found incidentally. TEE is the gold standard in diagnosis. This is a middle-aged man without a clear cause of ischemic strokes, subsequently found to have LE on the mitral valve. There is a paucity of evidence on the management of LE due to its rarity. Prior case reports suggest the use of antiplatelets/anticoagulants in symptomatic patients and surgery in cases of recurrent thromboembolic episodes refractory to conservative treatment. Given multiple strokes, this patient was started on anticoagulation and will be evaluated for surgery. Further high-powered studies are needed to guide management.

The preoperative focal cerebral blood flow status may be associated with slow flow in the bypass graft after combined surgery for moyamoya disease.

The aim of this study was to investigate the association between early postoperative slow flow in bypass grafts and preoperative focal cerebral blood flow (CBF) in patients who underwent combined surgery for moyamoya disease (MMD). The subjects were 18 patients (22 surgeries) who underwent single photon emission computed tomography (SPECT) before surgery. The CBF value of the middle cerebral artery territory was extracted from the SPECT data, and the value relative to the ipsilateral cerebellar CBF (relative CBF, or RCBF) was calculated. The association between RCBF and early postoperative slow flow in the bypass graft was investigated. In addition, the correlation between the revascularization effect and preoperative RCBF was analyzed. In four of 22 surgeries (18.2%), slow flow in the bypass graft was identified in the early postoperative period. Preoperative RCBF in the slow flow and patent groups was 0.86 ± 0.15 and 0.87 ± 0.15, respectively, with no significant difference (P = 0.72). The signal intensity of four slow-flowed bypasses was improved in all cases on magnetic resonance angiography images captured during the chronic phase (mean of 3.3 months postoperatively). The revascularization scores were 2 ± 0.82 and 2.1 ± 0.68 in the slow flow and patent groups, respectively, and did not differ significantly (P = 0.78). A significant correlation was not observed between preoperative RCBF and the revascularization effect. No significant association was observed between preoperative RCBF and early postoperative slow flow in bypass grafts in patients with MMD undergoing combined surgery. Given the high rate of improved depiction of slow-flowed bypass in the chronic postoperative phase, the conceptual significance of an opportune surgical intervention is to maintain CBF by supporting the patient's own intracranial-extracranial conversion function.

Outflow Patency Correlates with Radiosurgical Outcomes of Lateral Sinus Dural Arteriovenous Fistula.

To explore the impact of outflow patency on radiosurgical outcomes of lateral sinus dural arteriovenous fistulas (DAVFs). We retrospectively examined 83 lateral sinus DAVFs treated with Gamma Knife radiosurgery (GKRS) between 1995 and 2020. Two neuroradiologists blinded to the therapeutic outcomes served as imaging evaluators on pre-GKRS digital subtraction angiography and magnetic resonance images. The sinovenous outflow of lateral sinus DAVF was scored using combined conduit score (CCS), ranging from 0 (total occlusion) to 8 (full patency). The patients' follow-up magnetic resonance and digital subtraction angiography images were used to validate the radiosurgical outcomes (obliteration or non-obliteration) of lateral sinus DAVF. Cox regression and Kaplan-Meier analyses were performed to determine the correlations between the variables and outcomes. Among the 83 cases, 60 (72%) lateral sinus DAVFs achieved obliteration after a GKRS at a median latency period of 24.5months. After adjustment for aggressive presentation, cortical venous reflux, straight sinus reflux, and optic nerve sheath enlargement, a CCS of >6 was independently associated with lateral sinus DAVF obliteration (hazard ratio: 2.335, P=0.007). The estimated 36-month probabilities of obliteration were 80% versus 53.6% for lateral sinus DAVFs with a CCS of >6 versus ≤6. Lateral sinus DAVFs with a CCS of >6, indicating a nearly patent sinovenous outflow, were more likely to be obliterated after GKRS. Sinovenous outflow patency is a factor associated with therapeutic outcomes in radiosurgery for lateral sinus DAVFs.

Endovascular transmural access to carotid artery perivascular tissues: safety assessment of a novel technique

BackgroundRecent advances in endovascular devices have allowed access and targeting of perivascular tissues of the peripheral circulation. The perivascular tissues of the cervical and cranial circulations have many important structures...

Cerebrovascular Reserve Impairment in the Anterior Cerebral Artery Territory Predicts Deep Temporal Artery Enlargement After Combined Revascularization Surgery in Moyamoya Disease.

A combined surgery of direct and indirect revascularization has been frequently performed in patients with moyamoya disease, though the efficacy of indirect revascularization surgery in adult patients with moyamoya disease has not been established. This study aimed to evaluate superficial temporal artery (STA) and deep temporal artery (DTA) diameters 1day and 3months after combined revascularization surgery in patients with moyamoya disease. We also investigated clinical factors related to DTA enlargement after surgery. We examined 78 cerebral hemispheres in 57 adult and pediatric patients with moyamoya disease who underwent combined revascularization surgery [STA-MCA bypass and encephalo-duro-myo-synangiosis] in our institution. STA and DTA diameters were measured on axial magnetic resonance angiography images at 1day and 3months after surgery. DTA diameter increased in 64 hemispheres (82.1%). DTA diameter increase in association with STA diameter decrease was found in 39 hemispheres (50%). The proportion of hemispheres with a reduction in STA diameter was significantly higher in hemispheres with DTA enlargement than in hemispheres with DTA reduction (P=0.0088). Among the 64 hemispheres with DTA enlargement, 51 (79.7%) showed cerebrovascular reserve (CVR) impairment in the anterior cerebral artery (ACA) territory before surgery. CVR impairment in the ACA territory was the only clinical factor related to DTA enlargement (P<0.001). The DTA frequently enlarges after combined revascularization surgery, even in adult patients with moyamoya disease. In patients with impaired CVR in the ACA territory, blood supply from the DTA to the ACA territory can be expected after combined revascularization surgery.

A Combination of 3D TOF MRA and FIESTA Predicts Surgery-Needed Primary Trigeminal Neuralgia and Specific Offending Vessels.

To investigate the predictive accuracy of three-dimension (3D) time-of-flight (TOF) MR angiography (MRA) and 3D Fast Imaging Employing Steady-state Acquisition (FIESTA) techniques in assessing neurovascular compression (NVC) with specific vessels in patients with primary trigeminal neuralgia (TN). Patients with single-site primary TN undergoing microvascular decompression (MVD) were retrospectively recruited. All patients had available preoperative magnetic resonance imaging (MRI) scans. A quantitative NVC scoring system was applied to assess the severity of NVC on MRI. The radiological findings were correlated with the intraoperative result to determine the diagnostic accuracy of MRI techniques. Besides, the radiological indicator of MVD was determined. Seventy-three TN patients were recruited. Thirty-three patient had bilateral NVC but with unilateral neuralgia. The average NVC score of the asymptomatic side was significantly lower than that of the symptomatic side (1.6 vs. 6.7; p < 0.001). A cut-off value of NVC >4 was determined as a radiological indicator of MVD with sensitivity and specificity of 82.2% and 98.6%, respectively Area Under Curve (AUC = 0.97; p < 0.001). Approximately 90% of symptomatic patients had the distance to REZ ≤3 mm. 68.5% of patients had a single conflicting vessel, and superior cerebellar artery (SCA) was the predominate vessel (46.6%). The sensitivity and specificity of MRI to detect NVC were 95.8% and 100%, respectively. Regarding each vessel, the cohen's kappa statistic (K) was 0.632 overall. 3D TOF MRA and FIESTA show an overall good ability to predict specific offending vessels. NVC score >4 is identified to predict TN, suggestive of subsequent surgical treatment.

Evaluation of Circle of Willis variants using magnetic resonance angiography

The Circle of Willis (COW) is an important collateral pathway to protect the persistence of cerebral blood perfusion. This study aims to investigate the morphological variants of this significant vascular structure with a large study population. 867 patients who had undergone MR angiography (MRA) evaluation were enrolled in this study. The MRA images of these patients obtained by the three-dimensional time-of-flight technique were re-interpreted to measure the vessel diameters of all components of the COW and classify the COW variations. In addition, correlations of the vessel calibers and the integrity of the COW with gender and age groups were presented. There was female dominance in the study population, and the mean age was 48. Type A was the most common variation in anterior (75.78%) and posterior (53.98%) circulation. Types G and H were the other common variation in the anterior circulation, and types E and D were the second and third common variations in the posterior COW, respectively. Smaller calibration for both ICAs, both P1s and BA were observed in females compared with the male group. Diameters of the BA, and both P1 segments were lower, and the left PCom diameter was significantly higher in the patients with a complete circle. There was a significant sex and age difference regarding the distribution of the complete, partially complete, and incomplete circle groups. The significant differences in the vessel calibers of specific components of the COW for complete, partial, and incomplete circulations revealed by this study should be explained with further research. In addition, meta-analyses with other studies in the literature might be a guide to understanding the morphological alterations of the COW and their relationships with a complete and non-complete circle.