Noncontrast Magnetic Resonance Angiography Research Articles

Evaluating the diagnostic performance of non-contrast magnetic resonance angiography sequences in the pre-procedural comprehensive analysis of direct carotid cavernous fistula.

Endovascular treatment of direct carotid cavernous fistula (DCCF) requires invasive diagnostic cerebral angiography for diagnosis and planning; however, a less invasive modality like magnetic resonance angiography (MRA) can be useful, especially in high-risk cases. This single-centre study evaluated a newer MR angiography (MRA) sequence, silent MRA and the traditional time of flight (TOF) MRA for pre-procedural treatment planning of DCCF. All consecutive DCCF patients who underwent TOF, silent MRA and diagnostic cerebral angiography were included in the study. Angiographic features like rent size, location, draining veins and collateral communicating arteries were analysed and compared between the two MRA sequences, with digital subtraction angiography (DSA) as the gold standard. Fifteen patients were included in the study. TOF MRA exhibited better sensitivity (76.9% vs 69.2%) in identifying the rent location, correctly pinpointing the location in 93.3% compared to 73.3% with silent MRA. Both MRA sequences showed good agreement with DSA for primary sac and rent size. TOF MRA correctly identified 86.2% of 210 total venous structures compared to 96% by silent MRA. Silent MRA demonstrated higher sensitivity (90% vs 76%) and accuracy (87.69 vs 94.36) in visualisation of involved veins compared to TOF MRA. Arterial characteristics of DCCF like rent location and rent size were better assessed by TOF MRA. Although both MRA identified venous features, silent MRA correlated better with DSA irrespective of the size and proximity to the site of the fistula. Combining both sequences can evaluate various angioarchitectural features of DCCF useful for therapeutic planning.

Capabilities of Dynamic Magnetic Resonance Angiography in Patients With Cerebral Aneurysms in the Postoperative Period

Introduction: The leading cause of hemorrhagic stroke is a ruptured cerebral aneurysm (CA), accounting for 70%-85% of nontraumatic subarachnoid hemorrhages. The primary goals of CA treatment are to prevent a rupture, thrombosis, or symptoms of mass effect. The main treatment options for intracranial aneurysms are open clipping, flow-diverter device implantation, resection and stenting of aneurysms. Treated aneurysms should be monitored to assess the stability of the occlusion because more than 20% of surgically treated aneurysms are known to recur. Magnetic resonance angiography (MRA) has recently become increasingly attractive for the follow-up of surgically treated CAs because it is noninvasive, does not require hospitalization, and reduces complications associated with the frequent use of cerebral angiography.Objective: To evaluate capabilities of dynamic MRA in postoperative monitoring of patients with CAs.Materials and methods: The study was conducted at the premises of the Scientific Research Institute – Ochapovsky Regional Clinical Hospital No. 1 (Krasnodar, Russian Federation). In a hospital setting, 38 patients with CAs were examined in the late postoperative period. All the patients underwent magnetic resonance imaging, 3-dimensional time-of-flight (3D-TOF) MRA, and dynamic MRA followed by cerebral angiography. Imaging findings (MRA, dynamic MRA, and cerebral angiography) were evaluated by radiologists, x-ray surgeons, and neurosurgeons. They assessed treated aneurysms according to the Raymond-Roy occlusion classification: complete obliteration (class 1), residual neck (class 2), and residual aneurysm (class 3). Untreated aneurysms in patients with multiple CAs and de novo aneurysms were also assessed, and we looked for other vascular malformations.Results: The study was conducted in the late postoperative period from 6 to 18 months. A total of 38 patients participated in the study; of them 27 were women (age, 32-77 years) and 11 were men (age, 32-65 years). Dynamic MRA detected neck remnants of 4 clipped aneurysms and 2 embolized ones, which was confirmed by cerebral angiography. According to the dynamic MRA results, in case of clipped aneurysms neck remnants were found in the anterior communicating artery (n = 2), internal carotid artery (n = 1), and anterior choroidal artery (n = 1). In case of embolized aneurysms, neck remnants were revealed in the internal carotid artery (n = 1) and basilar artery (n = 1). Dynamic MRA also detected 5 additional aneurysms: 2 internal carotid artery aneurysms, 1 basilar artery aneurysm, 1 anterior cerebral artery aneurysm, and 1 anterior communicating artery aneurysm. These findings coincided with those of cerebral angiography. Based on the results of our study, the sensitivity and specificity of dynamic MRA in detecting CA neck remnants and untreated aneurysms were 100%.Discussion: Dynamic MRA findings are fully consistent with those of cerebral angiography in terms of determining an aneurysm occlusion status during postoperative follow-up. As for evaluation of de novo intracranial aneurysms, dynamic MRA is also superior to noncontrast 3D-TOF MRA in assessment of aneurysm shape and neck detection. Therefore, dynamic MRA can clearly visualize the structure of cerebral vessels mainly due to the effect of blood flow and static tissue contrast, and the principle is mainly the effect of multiphase scanning and accumulation of contrast agent.Conclusions: Dynamic MRA has a number of advantages over cerebral angiography, such as noninvasiveness, high-resolution images of the cerebral arteries, absence of radiation exposure, use of iodinated contrast agent, and absence of artifacts from metal clips or embolic material.

The effect of non-contrast enhanced MRA on patients with renal insufficiency and foot pain.

To investigate the feasibility of non-contrast magnetic resonance angiography of arteries and veins (NATIVE) sampling perfection with application optimized contrasts by using different flip angle evolution (SPACE) and quiescent interval single shot (QISS) in assessing foot arteries of patients with renal insufficiency and foot pain. Fifty-three patients (mean age = 44.2 ± 11.4 years, male: female = 27:26) underwent QISS and NATIVE-SPACE. The source images were reconstructed to maximum intensity projection and volume render. The image quality of QISS and NATIVE-SPACE was rated (0-3, poor to excellent), and was compared using Wilcoxon test. True or false positive was determined by comparing the findings of QISS and NATIVE-SPACE. The relative signal intensity of artery was obtained for each case, and was compared between QISS and NATIVE-SPACE using Mann Whitney test. The acquisition time of NATIVE-SPACE was significantly longer than that of QISS (178.4 ± 35.7 seconds vs 45.4 ± 8.9 seconds, P < .001). QISS had significantly lower image quality score versus NATIVE-SPACE (1.4 ± 0.5 vs 2.4 ± 0.6, P = .02). Fifteen percentage (8/53) NATIVE-SPACE cases had poor image quality due to the similarity of peak flow and minimum flow. The relative signal intensity was significantly lower in QISS versus NATIVE-SPACE (9.7 ± 1.3 vs 68.2 ± 12.4, P < .001). NATIVE-SPACE is valuable in evaluating foot arteries of patients with renal insufficiency. QISS can serve as an alternative test to NATIVE-SPACE.

Efficacy and reliability of three-dimensional fusion guidance for fluoroscopic navigation in transarterial embolization for refractory musculoskeletal pain.

This study aimed to evaluate the efficacy and reliability of three-dimensional (3D) fusion guidance in roadmapping for fluoroscopic navigation during trans-arterial embolization for refractory musculoskeletal pain (TAE-MSK pain) in the extremities. The included research patients were divided into two groups: group A-TAE-MSK pain performed without the use of 3D fusion guidance; group B-TAE-MSK pain performed with the use of 3D fusion guidance for fluoroscopic navigation. We compared the procedure time, radiation dose, visual analogue scale for pain scores, and adverse effects (before and 3 months after TAE-MSK pain) among the two groups. In the group B, we determined the reliability of ideal branch angle for pre-operative non-contrast 3D magnetic resonance angiography (MRA) and intra-operative 3D cone beam computed tomography (CBCT) angiography. We recruited 65 patients, including 23 males and 42 females (average age 58.20±12.58 years), with 38 and 27 patients in groups A and B. A total of 247 vessels were defined as target branch vessels. Significant changes were observed in the fluoroscopy time which was 32.31±12.39 and 14.33±3.06 minutes, in group A and group B (P<0.001), respectively; procedure time, which was 46.45±17.06 in group A and 24.67±9.78 in group B (P<0.001); and radiation exposure dose, determined as 0.71±0.64 and 0.34±0.29 mSv (P<0.01) in group A and group B, respectively. Furthermore, the number of target branch vessels, that underwent successful catheterization were 107 (97%) in group B as compared to 96 (70%) in group A, which was also significant (P<0.001). The study also showed that the ideal branch-angle has a similarly high consistency in pre-operative and intra-operative angiography based on the intra-class correlation coefficient (ICC) (0.994; 0.990, respectively). 3D fusion guidance for fluoroscopic navigation not only is a reliable process, but also effectively reduces the operation time and radiation dose of TAE-MSK pain.

Highly accelerated, Dixon-based non-contrast MR angiography versus high-pitch CT angiography

ObjectivesTo compare a novel, non-contrast, flow-independent, 3D isotropic magnetic resonance angiography (MRA) sequence that combines respiration compensation, electrocardiogram (ECG)-triggering, undersampling, and Dixon water-fat separation with an ECG-triggered aortic high-pitch computed tomography angiography (CTA) of the aorta.Materials and methodsTwenty-five patients with recent CTA were scheduled for non-contrast MRA on a 3 T MRI. Aortic diameters and cross-sectional areas were measured on MRA and CTA using semiautomatic measurement tools at 11 aortic levels. Image quality was assessed independently by two radiologists on predefined aortic levels, including myocardium, proximal aortic branches, pulmonary veins and arteries, and the inferior (IVC) and superior vena cava (SVC). Image quality was assessed on a 5-point Likert scale.ResultsAll datasets showed diagnostic image quality. Visual grading was similar for MRA and CTA regarding overall image quality (0.71), systemic arterial image quality (p = 0.07–0.91) and pulmonary artery image quality (p = 0.05). Both readers favored MRA for SVC and IVC, while CTA was preferred for pulmonary veins (all p < 0.05). No significant difference was observed in aortic diameters or cross-sectional areas between native MRA and contrast-enhanced CTA (p = 0.08–0.94).ConclusionThe proposed non-contrast MRA enables robust imaging of the aorta, its proximal branches and the pulmonary arteries and great veins with image quality and aortic diameters and cross-sectional areas comparable to that of CTA. Moreover, this technique represents a suitable free-breathing alternative, without the use of contrast agents or ionizing radiation. Therefore, it is especially suitable for patients requiring repetitive imaging.

Simultaneous, free-breathing, non-contrast 3D whole-heart coronary magnetic resonance angiography and vulnerable plaque imaging in patients with suspected acute coronary syndrome

Abstract Background Coronary artery high-risk plaque identified on cardiovascular magnetic resonance (CMR) is associated with future coronary events, independent of coronary artery luminal stenosis. We have recently developed a 3-dimensional whole-heart free-breathing non-contrast CMR sequence that allows for simultaneous high-resolution visualisation of the coronary arteries and vulnerable plaque on co-registered bright and black blood images (iT2prep-BOOST) with 100% respiratory scan efficiency. Objectives To validate iT2prep-BOOST in patients with non-ST-segment elevation myocardial infarction (NSTEMI) against the reference standard imaging modalities of invasive X-ray coronary angiography and intravascular imaging [optical coherence tomography (OCT)/intravascular ultrasound (IVUS)]. Methods 41 consecutive patients with suspected NSTEMI, based upon clinical history, electrocardiographic changes and positive high-sensitivity troponin assays, were recruited into the study. Invasive coronary angiography ± intravascular imaging was used to classify coronary segments into the following categories: normal, non-culprit and culprit segments; stenosed segments as well as segments with vulnerable plaque features (lipid, calcium, fibroatheroma, thin cap fibroatheroma (TCFA), plaque rupture and thrombus). The highest plaque/myocardial signal intensity ratio (PMR) in each coronary segment was analysed on iT2prep-BOOST. Results The mean iT2prep-BOOST acquisition time was 10.8 ± 1.3 minutes. The mean ± standard error of mean (SEM) PMR of culprit segments was significantly higher than non-culprit segments, which was significantly higher than normal segments (1.01 ± 0.05 vs. 0.67 ± 0.01 vs. 0.35 ± 0.01, P&amp;lt;0.001). Coronary segments with lipid, calcium and fibroatheroma had a significantly higher PMR compared to normal coronary segments (P&amp;lt;0.001) but lower than segments with TCFA, plaque rupture and thrombus (P&amp;lt;0.001). There was a progressive increase in PMR with increasing degree of coronary stenosis (P&amp;lt;0.001). Patients with type 2 diabetes, hypertension, hyperlipidaemia and family history of coronary artery disease had a significantly higher PMR on iT2prep-BOOST (P&amp;lt;0.001, P=0.02, P=0.04 and P=0.02 respectively). Finally, PMR was positively correlated with HbA1c, total cholesterol, non-HDL cholesterol, LDL cholesterol and triglyceride levels (P&amp;lt;0.001, P=0.02, P=0.02, P=0.05 and P=0.05 respectively). Conclusions In summary, the proposed iT2prep-BOOST framework has the potential to simultaneously acquire coronary artery angiography and to differentiate normal segments from non-culprit and culprit plaque segments. Furthermore, PMR is associated with both biochemical and patient related risk factors for coronary artery disease (CAD). The long-term prognostic value of PMR needs to be investigated in a longitudinal multi-centre study of patients with suspected CAD.Figure 1Figures 2 and 3

Utility of Carbon Dioxide Venography and Intraprocedural CT for Adrenal Venous Sampling in Patients with an Allergy to Iodinated Contrast Media

PurposeTo assess the diagnostic performance of carbon dioxide (CO2) and intraprocedural unenhanced computed tomography (CT) for adrenal venous sampling (AVS) (CO2–intraprocedural unenhanced CT–AVS) in patients with primary aldosteronism (PA) and a history of iodine contrast medium allergy. Materials and MethodsCO2–intraprocedural unenhanced CT–AVS was performed in 18 patients with iodine contrast media allergies at the authors’ hospital between December 2015 and January 2021. CT and noncontrast magnetic resonance angiography were used to evaluate the preoperative adrenal vein anatomy. CO2 venography was performed to confirm adrenal vein catheterization. Additionally, intraprocedural unenhanced CT was also performed to confirm catheter position in the right adrenal gland. ResultsIn all cases in which CO2–intraprocedural unenhanced CT–AVS was performed, the right and left adrenal veins were catheterized appropriately, leading to a localized diagnosis. Catheterization of the left adrenal vein was confirmed using CO2 venography in all cases. In 7 of the 18 cases, CO2 venography demonstrated selection of the right adrenal vein. In 15 of 18 cases, intraprocedural unenhanced CT demonstrated selection of the right adrenal vein. ConclusionsCO2–intraprocedural unenhanced CT–AVS demonstrated the same diagnostic ability for PA localization as conventional AVS with iodine contrast media. The proposed method is clinically feasible for AVS, in which iodine contrast media use is restricted.

Mathematical Analysis of the Effectiveness of Screening for Intracranial Aneurysms in First-Degree Relatives of Persons with Subarachnoid Hemorrhage

Population screening for aneurysms in patients with risk factors and preventive surgical treatment are beneficial according to numerous studies. One of the most significant risk factors is heredity, namely, the presence of first-degree relatives (FDR) with aneurysmal subarachnoid hemorrhage (aSAH). Nevertheless, there are still no generally accepted approaches or evidence bases regarding the benefits of the aneurysm screening strategy. Mathematical modeling of the dynamics of aneurysm development in the population was carried out using an algorithm implementing a discrete Markov's chain. To implement the model, all probabilities of events and distributions are taken from available literature sources. Three-dimensional time of flight noncontrast magnetic resonance angiography was chosen as a screening method. Patients underwent preventive surgical treatment if an aneurysm was detected. Screening and preventive treatment in the general population reduces the prevalence of aneurysms by 1.74% (3.44% in the FDR group) and the prevalence of aSAH by 14.36% (37.48% in the FDR group). Mortality due to aSAH was reduced by 14.44%. The number of disabilities also decreases. The occurrence of deep disability was reduced by 20.2% in the FDR group. Economic analysis of the part of the population consisting of FDRs showed annual savings of ies also decr CONCLUSIONS: The mathematical model demonstrated that screening and preventive treatment of cerebral aneurysms can reduce aSAH-associated morbidity and mortality. In the FDR group, there was decrease in the prevalence of aSAH and decrease in associated mortality. Screening for cerebral aneurysms is cost-effective.

Characteristics and predictors of low-grade renal artery stenosis in female patients with CKD

ABSTRACT Aim Renal artery stenosis (RAS) is an important cause of chronic kidney disease (CKD). The main purpose of this study was to explore the clinical characteristics and predictors of low-grade RAS in female patients with CKD. Methods One hundred and five female CKD patients from Huadong Hospital affiliated with Fudan University who underwent 3 T non-contrast renal artery magnetic resonance angiography (MRA) were analyzed. Basic statistics methods were used in the study, such as independent-sample t test,non-parametric test, binary logistic regression analysis and ROC analysis. Results In this cross-sectional study, there were 50 patients with RAS and 55 without RAS (47.6% versus 52.4%). Binary logistic regression analysis demonstrated that low-level ALB and lymphocyte count, high-level SP, BUN and NLR were independent risk factors for low-grade RAS in female patients with CKD. ROC analysis indicated that eGFR, FeNa and UBCR, ALB, lymphocyte count and NLR had the best predictive value for low-grade RAS, especially eGFR with a sensitivity of 65.50% and specificity of 72.00% and FeNa with a sensitivity of 71.10% and specificity of 72.20% and BUCR with a sensitivity of 71.10% and specificity of 68.10%. Conclusion In female patients with CKD, FeNa, eGFR, ALB, UBCR, lymphocyte count and NLR may be good predictors of low-grade RAS, especially eGFR, FeNa and BUCR.

3D whole-heart noncontrast coronary MR angiography based on compressed SENSE technology: a comparative study of conventional SENSE sequence and coronary computed tomography angiography

ObjectiveThe relatively long scan time has hampered the clinical use of whole-heart noncontrast coronary magnetic resonance angiography (NCMRA). The compressed sensitivity encoding (SENSE) technique, also known as the CS technique, has been found to improve scan times. This study aimed to identify the optimal CS acceleration factor for NCMRA.MethodsThirty-six participants underwent four NCMRA sequences: three sequences using the CS technique with acceleration factors of 4, 5, and 6, and one sequence using the conventional SENSE technique with the acceleration factor of 2. Coronary computed tomography angiography (CCTA) was considered as a reference sequence. The acquisition times of the four NCMRA sequences were assessed. The correlation and agreement between the visible vessel lengths obtained via CCTA and NCMRA were also assessed. The image quality scores and contrast ratio (CR) of eight coronary artery segments from the four NCMRA sequences were quantitatively evaluated.ResultsThe mean acquisition time of the conventional SENSE was 343 s, while that of CS4, CS5, and CS6 was 269, 215, and 190 s, respectively. The visible vessel length from the CS4 sequence showed good correlation and agreement with CCTA. The image quality score and CR from the CS4 sequence were not statistically significantly different from those in the other groups (p > 0.05). Moreover, the image score and CR showed a decreasing trend with the increase in the CS factor.ConclusionsThe CS technique could significantly shorten the acquisition time of NCMRA. The CS sequence with an acceleration factor of 4 was generally acceptable for NCMRA in clinical settings to balance the image quality and acquisition time.

Non-contrast MR angiography of pelvic arterial vasculature using the Quiescent interval slice selective (QISS) sequence.

To evaluate Quiescent Interval Slice Selective (QISS) balanced steady-state free precession (bSSFP) and QISS fast low-angle shot (FLASH) sequences for non-contrast Magnetic Resonance Angiography (MRA) of iliac arteries regarding image quality and diagnostic confidence in order to establish these sequences in daily clinical practice. A prospective study of healthy subjects (n = 10) was performed. All subjects underwent the QISS MRI protocol with bSSFP und FLASH sequences. Vessel contrast-to-background ratio (VCBR) were measured in pre-defined vessel segments. Image quality and diagnostic confidence was assessed using a Likert scale (five-point scale). Inter-reader agreement was determined using Cohen's kappa coefficient (κ). Ten healthy subjects (median age 29 years, IQR: 26.25 to 30 years) were included in this prospective study. Median MR examination time was 2:05min (IQR 1:58 to 2:16) for QISS bSSFP and 4:11min (IQR 3:57 to 4:32) for QISS FLASH. Both sequences revealed good VCBR in all examined vessel segments. VCBR (muscle tissue) were marginally higher for FLASH sequences (e.g., 0.82 vs. 0.78 in the right femoral artery, p = 0.035*), while bSSFP sequence showed significantly higher VCBR (fat tissue) in the majority of examined arterials vessels (e.g., 0.78 vs. 0.62 in right femoral artery, p = 0.001*). The image quality and diagnostic confidence of both sequences were rated as good to excellent. Moderate to good inter-reader agreement was found. QISS MRA using bSSFP and FLASH sequences are diagnostic for visualization of iliac arterial vasculature. The QISS bSSFP sequence might offer advantages due to the markedly shorter exam time and superior visualization of smaller vessels. The QISS FLASH sequence seems to be a robust alternative for non-contrast MRA since it is less sensitive to magnetic field inhomogeneities.

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.

Evaluation of peripheral arterial disease using noncontrast magnetic resonance angiography

Evaluation of peripheral arterial disease using noncontrast magnetic resonance angiography

Noncontrast time-resolved pulmonary magnetic resonance angiography with consecutive beam saturation pulse and variable flip angles using three-dimensional fast spin echo: A preliminary study

To develop and validate a novel noncontrast time-resolved magnetic resonance angiography (NC TR-MRA) using consecutive beam pulses with variable flip angles for visualizing hemodynamics in the pulmonary artery, we performed phantom and volunteer studies and applied the novel NC TR-MRA to a 51-year-old woman with pulmonary arteriovenous malformation (PAVM).The novel NC TR-MRA sequence utilized consecutive multiple-beam saturation pulses with variable flip angles considering venous blood T1 relaxation to alter the visualized blood signal length. The flowing blood signal length is suppressed according to the number of beam saturation pulses. NC TR-MRA in each flow phase was assessed by subtracting the images with and without beam saturation pulses. In the flow phantom study, three flow velocities were used to simulate physiological pulmonary arterial blood flow. Signal profiles along the flow direction were evaluated in each flow phase. In the volunteer study, five healthy volunteers were recruited, and NC TR-MRA was applied to evaluate relationships between the flow-saturated time and signal enhancement rates. Four regions of interest (ROIs) were determined on the proximal and distal portions of the right basal artery. A patient with PAVM was included to validate whether a PAVM lesion could be visualized using NC TR-MRA. The visualized flow signal lengths extended proportionally with the number of beam saturation pulses in the steady-flow phantom at all velocities. In the volunteer study, NC TR-MRA images showed signal enhancement from the proximal to distal portions of the right basal artery with increase in the flow-saturated time. Signal enhancement rates in all ROIs were significantly positively correlated with the flow-saturated time (p < 0.001 in all ROIs). Further, the lesion and its hemodynamics could be explicitly visualized in the patient with PAVM. Hence, NC TR-MRA using beam saturation pulse can visualize the hemodynamics of the pulmonary artery and may be useful for diagnosing and following patients with PAVM.

Quiescent-Interval Single-Shot Magnetic Resonance Angiography May Outperform Carbon-Dioxide Digital Subtraction Angiography in Chronic Lower Extremity Peripheral Arterial Disease.

Nephroprotective imaging in peripheral arterial disease (PAD) is often crucial. We compared the diagnostic performance of non-contrast Quiescent-interval single-shot magnetic resonance angiography (QISS MRA) and carbon-dioxide digital subtraction angiography (CO2 DSA) in chronic lower extremity PAD patients. A 19-segment lower extremity arterial model was used to assess the degree of stenosis (none, <50%, 50–70%, >70%) and the image quality (5-point Likert scale: 1-non-diagnostic, 5-excellent image quality). Intra-class correlation coefficient (ICC) was calculated for inter-rater reliability. Diagnostic accuracy and interpretability were evaluated using CO2 DSA as a reference standard. 523 segments were evaluated in 28 patients (11 male, mean age: 71 ± 9 years). Median and interquartile range of subjective image quality parameters for QISS MRA were significantly better compared to CO2 DSA for all regions: (aortoiliac: 4 [4–5] vs. 3 [3–4]; femoropopliteal: 4 [4–5] vs. 4 [3–4]; tibioperoneal: 4 [3–5] vs. 3 [2–3]; all regions: 4 [4–5] vs. 3 [3–4], all p < 0.001). QISS MRA out-performed CO2 DSA regarding interpretability (98.3% vs. 86.0%, p < 0.001). Diagnostic accuracy parameters of QISS MRA for the detection of obstructive luminal stenosis (70%<) as compared to CO2 DSA were as follows: sensitivity 82.6%, specificity 96.9%, positive predictive value 89.1%, negative predictive value 94.8%. Regarding the degree of stenosis, interobserver variability for all regions was 0.97 for QISS MRA and 0.82 for CO2 DSA. QISS MRA proved to be superior to CO2 DSA regarding subjective image quality and interpretability for the imaging of chronic lower extremity PAD.

Comprehensive study of magnetic resonance angiography of circle of Willis in population of Western Uttar Pradesh

Background: Circulus Arteriosus cerebrii, another name for Circle of Willis, establishes a polygonal anastomotic channel between two internal carotid arteries and two vertebral arteries. The arterial circle is located in the interpeduncular fossa, near the base of the brain. It has been established through anatomical and radiological studies that there are anatomical variations in healthy persons. Aim: To evaluate the anatomical variations in arteries of circle of Willis supplying brain through Magnetic Resonance Angiography (MRA) in population of western UP. Methods and Materials: This cross-sectional study included 264 patients who met inclusion criteria. Non-contrast Magnetic Resonance Angiography of Circle of Willis was carried out among the individuals after a written informed consent. Angiography of brain (circle of Willis) scanning protocol consisted of 3-dimensional time of flight Trans axial acquisition. MRA of brain was performed on GE 1.5 TESLA Optima MRI machine. MRA Brain angiography images were viewed for normal pattern of arterial anatomy and their variations. Results: The complete variant in male was 58.9% (n=103) while in females it was 59.6% (n=53). The incomplete variant in male &amp; females was 41.1% (n=72) and 40.4% (n=36) respectively.

Non-contrast free-breathing 3D cardiovascular magnetic resonance angiography using REACT (relaxation-enhanced angiography without contrast) compared to contrast-enhanced steady-state magnetic resonance angiography in complex pediatric congenital heart disease at 3T

BackgroundTo evaluate the great vessels in young children with complex congenital heart disease (CHD) using non-contrast cardiovascular magnetic resonance angiography (CMRA) based on three-dimensional relaxation-enhanced angiography without contrast (REACT) in comparison to contrast-enhanced steady-state CMRA.MethodsIn this retrospective study from April to July 2021, respiratory- and electrocardiogram-gated native REACT CMRA was compared to contrast-enhanced single-phase steady-state CMRA in children with CHD who underwent CMRA at 3T under deep sedation. Vascular assessment included image quality (1 = non-diagnostic, 5 = excellent), vessel diameter, and diagnostic findings. For statistical analysis, paired t-test, Pearson correlation, Bland–Altman analysis, Wilcoxon test, and intraclass correlation coefficients (ICC) were applied.ResultsThirty-six young children with complex CHD (median 4 years, interquartile range, 2–5; 20 males) were included. Native REACT CMRA was obtained successfully in all patients (mean scan time: 4:22 ± 1:44 min). For all vessels assessed, diameters correlated strongly between both methods (Pearson r = 0.99; bias = 0.04 ± 0.61 mm) with high interobserver reproducibility (ICC: 0.99 for both CMRAs). Native REACT CMRA demonstrated comparable overall image quality to contrast-enhanced CMRA (3.9 ± 1.0 vs. 3.8 ± 0.9, P = 0.018). With REACT CMRA, better image quality was obtained at the ascending aorta (4.8 ± 0.5 vs. 4.3 ± 0.8, P < 0.001), coronary roots (e.g., left: 4.1 ± 1.0 vs. 3.3 ± 1.1, P = 0.001), and inferior vena cava (4.6 ± 0.5 vs. 3.2 ± 0.8, P < 0.001). In all patients, additional vascular findings were assessed equally with native REACT CMRA and the contrast-enhanced reference standard (n = 6).ConclusionIn young children with complex CHD, REACT CMRA can provide gadolinium-free high image quality, accurate vascular measurements, and equivalent diagnostic quality compared to standard contrast-enhanced CMRA.

Integrated head and neck imaging of symptomatic patients with stroke using simultaneous non-contrast cardiovascular magnetic resonance angiography and intraplaque hemorrhage imaging as compared with digital subtraction angiography

BackgroundBoth stenosis rate and intraplaque hemorrhage (IPH) are important predictors of stroke risk. Simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) cardiovascular magnetic resonance (CMR) imaging can detect both stenosis rate and IPH. We aimed to evaluate consistency between SNAP and digital subtraction angiography (DSA) to assess symptomatic patients with stroke and explore the performance of SNAP to identify IPH and the clinical factors associated with IPH.MethodsEighty-one symptomatic patients with stroke, admitted to Wuhan Union Hospital who underwent CMR high-resolution vessel wall imaging (HR-VWI) and SNAP, were retrospectively identified. For patients who received interventional therapy, the imaging functions of SNAP and HR-VWI were compared with DSA. The diameters of the intracranial and carotid vessels were measured, and stenotic vessels were identified. The consistency of SNAP and HR-VWI in identifying IPH was also examined, and the correlations between IPH and clinical factors were analyzed.ResultsSNAP was more consistent with DSA than HR-VWI in measuring vascular stenosis (intraclass correlation coefficient [ICC]SNAP-DSA = 0.917, ICC HR-VWI-DSA = 0.878). Regarding the diameter measurements of each intracranial and carotid vessel segment, SNAP was superior or similar to HR-VWI, and both were consistent with DSA in the measurement of major intracranial vascular segments. HR-VWI and SNAP exhibited acceptable agreement in identifying IPH (Kappa = 0.839, 95% confidence interval [CI]: 0.704–0.974). Patients who underwent interventional therapy had a higher plaque burden (P < 0.001). Patients with IPH had lower levels of high-density lipoprotein cholesterol (HDL) (P = 0.038) and higher levels of blood glucose (P = 0.007) and cystatin C (P = 0.040).ConclusionsCMR SNAP is consistent with DSA in measuring vessel diameters and identifying atherosclerosis stenosis in each intracranial and carotid vessel segment. SNAP is also a potential alternative to HR-VWI in identifying stenosis and IPH.

Cerebral Blood Flow, Brain Volume, and Age Predicts Executive Function in Sickle Cell Anemia

Introduction: Individuals with sickle cell anemia (SCA) are at increased risk for deficits in multiple domains of neurocognitive functioning, including executive functions. In addition to assessing the effects of silent cerebral infarcts (SCI) and stroke on cognition, prior research has focused on hemoglobin and transcranial Doppler velocity as hemodynamic correlates. Recent studies have begun to use more precise measures of blood delivery to the brain (e.g., cerebral blood flow; CBF) to determine more sensitive indicators of cognitive risk prior to neurological injury. Nevertheless, empirical and meta-analytic findings suggest that these deficits increase with age, which can have broad impact on psychosocial functioning, including self-management and navigation through the transition from pediatric to adult medical care. This study aimed to assess brain volume as a mediator of the association between CBF and executive functioning in a sample of individuals with SCA. The secondary aim was to assess age as a moderator of hemodynamic and structural correlates of executive function.Methods: Children, adolescents, and young adults with SCA were enrolled prospectively. Each participant received a 3-Tesla non-contrast magnetic resonance imaging and magnetic resonance angiography of the brain, and a neurological examination by the study neurologist. Gray matter CBF was calculated from pseudo-continuous arterial spin labeling using the solution to the flow-modified Bloch equation after correcting for individual hematocrit. Three measures of brain volume were also computed from 3D-T1 images using Freesurfer version 7.1.1: total brain volume, gray matter volume, and white matter volume was calculated as the difference between the two. At a separate study visit, participants completed an age-appropriate Wechsler Working Memory Index (WMI). Pearson correlations assessed bivariate associations among variables, SPSS PROCESS macro was used to test gray matter volume as a mediator in the relation between CBF and working memory, and multiple linear regression analyses tested age as a moderator of the impact of CBF and brain volume on working memory.Results: Twenty-nine children and adolescents (ages 6 to 17 years) and 25 adults (ages 18 to 31 years) were enrolled. Five participants were excluded from analyses due to history of overt stroke that resulted in significant brain volume loss. Of 49 included participants, 20 had SCIs. Working memory was inversely correlated with age (r = -.30, p = .037) and CBF (r = -.36, p = .013), such that WMI decreased cross-sectionally with older age and higher CBF. Working memory was positively correlated with gray matter volume (r = .42, p = .002); however, it was not related to white matter volume (r = -.05, p = .715) or total brain volume (r = -.07, p = .642). Finally, patient age was positively correlated with CBF (r = .36, p = .014), but the association of age with gray matter volume did not reach statistical significance (r = -.27, p = .065). Analyses in Figure 1 show that although CBF and gray matter were directly related to working memory (path c and path b, respectively), gray matter volume did not mediate the association between CBF and working memory (path a*b). However, regression analyses (Table 1) showed that age moderated the association between gray matter volume and working memory, such that there was only a significant relation in children and adolescents. This association did not exist for young adults (Figure 2).Conclusions: Neurocognitive assessments has been cited as an important standard of care for children and adolescents with SCA. Given the increase in deficits with age, and the increase in mortality after transferring from pediatric to adult care, monitoring executive function abilities and potential impact on self-management should continue into adulthood. Findings from the current study provide preliminary evidence that cerebral hemodynamic compensation with elevated CBF may be insufficient to prevent gray matter volume loss in children and adolescents and decline in working memory ability. Some limitations of the current study include small sample size and whole brain gray and white matter volumes as opposed to specific regions relevant to executive functions (e.g., prefrontal cortex); however, findings from global measures provide promising evidence for future research on hemodynamic and structural predictors of executive function in SCA. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The Use of Pointwise Encoding Time Reduction With Radial Acquisition MRA to Assess Middle Cerebral Artery Stenosis Pre- and Post-stent Angioplasty: Comparison With 3D Time-of-Flight MRA and DSA.

Background and Purpose: 3D pointwise encoding time reduction magnetic resonance angiography (PETRA-MRA) is a promising non-contrast magnetic resonance angiography (MRA) technique for intracranial stenosis assessment but it has not been adequately validated against digital subtraction angiography (DSA) relative to 3D-time-of-flight (3D-TOF) MRA. The aim of this study was to compare PETRA-MRA and 3D-TOF-MRA using DSA as the reference standard for intracranial stenosis assessment before and after angioplasty and stenting in patients with middle cerebral artery (MCA) stenosis.Materials and Methods: Sixty-two patients with MCA stenosis (age 53 ± 12 years, 43 males) underwent MRA and DSA within a week for pre-intervention evaluation and 32 of them had intracranial angioplasty and stenting performed. The MRAs' image quality, flow visualization within the stents, and susceptibility artifact were graded on a 1–4 scale (1 = poor, 4 = excellent) independently by three radiologists. The degree of stenosis was measured by two radiologists independently on DSA and MRAs.Results: There was an excellent inter-observer agreement for stenosis assessment on PETRA-MRA, 3D-TOF-MRA, and DSA (ICCs > 0.90). For pre-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA (3.87 ± 0.34 vs. 3.38 ± 0.65, P < 0.001), and PETRA-MRA had better agreement with DSA for stenosis measurements compared to 3D-TOF-MRA (r = 0.96 vs. r = 0.85). For post-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA for in-stent flow visualization and susceptibility artifacts (3.34 ± 0.60 vs. 1.50 ± 0.76, P < 0.001; 3.31 ± 0.64 vs. 1.41 ± 0.61, P < 0.001, respectively), and better agreement with DSA for stenosis measurements than 3D-TOF-MRA (r = 0.90 vs. r = 0.26). 3D-TOF-MRA significantly overestimated the stenosis post-stenting compared to DSA (84.9 ± 19.7 vs. 39.3 ± 13.6%, p < 0.001) while PETRA-MRA didn't (40.6 ± 13.7 vs. 39.3 ± 13.6%, p = 0.18).Conclusions: PETRA-MRA is accurate and reproducible for quantifying MCA stenosis both pre- and post-stenting compared with DSA and performs better than 3D-TOF-MRA.