Cine Phase-contrast Magnetic Resonance Imaging Research Articles

Abdominal Aortic Hemodynamics in Intermittent Claudication Patients at Rest and during Dynamic Pedaling Exercise

Lower-extremity exercise has been shown to eliminate adverse hemodynamics conditions, such as low and oscillating blood flow and wall shear stress, in the abdominal aortas of healthy young and older adults. We use cine phase-contrast magnetic resonance imaging and a custom MRI-compatible exercise cycle to quantify hemodynamic changes because of pedaling exercise in patients diagnosed with intermittent claudication. With only an average heart increase of 35 ± 18% and exercise workload of 36 ± 16 watts, the patients experienced approximately 3- and 6-fold increases in blood flow, and 4- and 16-fold increases in wall shear stress at the supraceliac and infrarenal aortic locations, respectively. Also, all oscillations in flow and shear stress at rest were eliminated with exercise. Claudication patients experience 3- to 4-fold lower oscillations in flow and shear stress at rest as compared with healthy age-matched controls, likely because of reduced distal arterial compliance as a result of distal atherosclerosis. The magnitude of flow and shear oscillatory indices may be good indicators of distal arterial compliance and health, and may provide predictive power for the efficacy of focal interventions.

MR-derived cerebral spinal fluid hydrodynamics as a marker and a risk factor for intracranial hypertension in astronauts exposed to microgravity.

To quantify the change in cerebral spinal fluid (CSF) production rate and maximum systolic velocity in astronauts before and after exposure to microgravity and identify any physiologic trend and/or risk factor related to intracranial hypertension. Following Institutional Review Board (IRB) approval, with waiver of informed consent, a retrospective review of 27 astronauts imaged at 3T was done. Qualitative analysis was performed on T2 -weighted axial images through the orbits for degree of flattening of the posterior globe according to the following grades: 0 = none, 1 = mild, 2 = moderate, and 3 = severe. One grade level change postflight was considered significant for exposure to intracranial hypertension. CSF production rate and maximum systolic velocity was calculated from cine phase-contrast magnetic resonance imaging and compared to seven healthy controls. Fourteen astronauts were studied. The preflight CSF production rate in astronauts was similar to controls (P = 0.83). Six astronauts with significant posterior globe flattening demonstrated a 70% increase in CSF production rate postflight compared to baseline (P = 0.01). There was a significant increase in CSF maximum systolic velocity in the subgroup without posterior globe flattening (P = 0.01). The increased postflight CSF production rate in astronauts with positive flattening is compatible with the hypothesis of microgravity-induced intracranial hypertension inferring downregulation in CSF production in microgravity that is upregulated upon return to normal gravity. Increased postflight CSF maximum systolic velocity in astronauts with negative flattening suggests increased craniospinal compliance and a potential negative risk factor to microgravity-induced intracranial hypertension.

Quantitative Analysis of Wall Shear Stress for Human Carotid Bifurcation at Cardiac Phases by the Use of Phase Contrast Cine Magnetic Resonance Imaging: Computational Fluid Dynamics Study

Detailed strategy for regional hemodynamics is significant for knowledge of plaque development on vascular diseases such as atherosclerosis. The aim of this study was to derive relation between atherosclerosis and hemodynamics at human carotid bifurcation by the use of computational fluid dynamics (CFD), and to provide more accurate hemodynamic information. Blood velocity datasets at common carotid artery were obtained by phase-contrast cine magnetic resonance imaging (PC cine MRI). Carotid bifurcation model was computed for systolic, mid-diastolic, and end-diastolic phase. Comparison of wall shear stress (WSS) was performed for each cardiac phase. PC cine MRI provided velocity measurement for common carotid artery with various cardiac phases. The blood velocity had acute variation from 0.21 m/s to 1.07 m/s at systolic phase. The variation of WSS during cardiac phase was presented at carotid bifurcation model. High shear stress area was observed at dividing wall for all cardiac phases. The systole-diastole WSS ratio was 10.15 at internal carotid side of bifurcation. And low shear stress (<0.5 Pa) was observed at internal carotid side of bifurcation. Bifurcation area represented low shear stress and changed significantly WSS. The specific area with significant change in shear stress and low shear stress had good agreement with predilection sites of atherosclerosis. The result suggested that hemodynamics was related to atherosclerosis, and CFD analysis with various cardiac phases that were provided by PC cine MRI was allowed to determine an accurate analysis condition. This led to the representation of hemodynamics in vivo.

Cerebral arterial inflow assessment with 18F-FDG PET: Methodology and feasibility

Positron emission tomography (PET) with 18fluorodeoxyglucose (18F-FDG) is increasingly used in neurology. The measurement of cerebral arterial inflow (QA) using 18F-FDG complements the information provided by standard brain PET imaging. Here, injections were performed after the beginning of dynamic acquisitions and the time to arrival (t0) of activity in the gantry's field of view was computed. We performed a phantom study using a branched tube (internal diameter: 4mm) and a 18F-FDG solution injected at 240mL/min. Data processing consisted of (i) reconstruction of the first 3s after t0, (ii) vascular signal enhancement and (iii) clustering. This method was then applied in four subjects. We measured the volumes of the tubes or vascular trees and calculated the corresponding flows. In the phantom, the flow was calculated to be 244.2mL/min. In each subject, our QA value was compared with that obtained by quantitative cine-phase contrast magnetic resonance imaging; the mean QA value of 581.4±217.5mL/min calculated with 18F-FDG PET was consistent with the mean value of 593.3±205.8mL/min calculated with quantitative cine-phase contrast magnetic resonance imaging. Our 18F-FDG PET method constitutes a novel, fully automatic means of measuring QA.

Magnetic Resonance of Coronary Arteries

The assessment of luminal narrowing and altered blood flow in the coronary artery is challenging because of the small size of the vessel and the complex motion caused by cardiac contraction and respiration. Free-breathing, whole-heart coronary magnetic resonance angiography (MRA) has been introduced as a method that can provide visualization of all 3 major coronary arteries within a single 3-dimensional acquisition, either by using 1.5 T steady-state free precession or 3 T gradient-echo sequences. Recent studies have indicated that coronary MRA has sufficient diagnostic accuracy for excluding coronary artery disease (CAD) in patients with suspected CAD. Furthermore, coronary MRA can provide risk stratification for future cardiac events. In addition to the morphologic assessment of the coronary artery, phase-contrast cine MR imaging has unique advantages because it allows for measurement of blood flow and flow reserve in the coronary arteries. Comprehensive assessment of the morphology and blood flow in the coronary artery has a great potential in noninvasive detection of physiologically significant CAD that requires revascularization. The aim of this review is to provide an update on current technical improvements in coronary MRA and MR flow measurement of coronary arteries.

Altered coronary endothelial function in young smokers detected by magnetic resonance assessment of myocardial blood flow during the cold pressor test

Endothelial dysfunction is a key element in early atherogenesis. The purposes of this study were to evaluate the feasibility of magnetic resonance (MR) assessment of altered myocardial blood flow (MBF) in response to the cold pressor test (CPT) and to determine if coronary endothelial dysfunction in young smokers can be detected with this noninvasive approach. Fourteen healthy non-smokers (31±6years) and 12 smokers (34±8years) were studied. Breath-hold phase-contrast cine MR imaging (PC-MRI) of the coronary sinus (CS) were obtained at rest and during the CPT. MBF was measured as CS flow divided by left ventricle mass and the rate pressure product. In non-smokers, MBF was 0.88±0.19ml/min/g at rest and significantly increased to 1.13±0.26ml/min/g during the CPT (P=0.0001). In smokers, MBF was 0.94±0.26ml/min/g at rest and 0.96±0.30ml/min/g during the CPT (P=0.73). ΔMBF (MBF during the CPT-MBF at rest) was significantly reduced in smokers compared with non-smokers (0.02±0.20 vs. 0.26±0.18ml/min/g, P=0.005). The intra-class correlation coefficient between measurements by two observers was 0.90 for ΔMBF. A significant reduction in MBF response to CPT was demonstrated in young smokers with PC-MRI at 1.5T. This noninvasive method has great potential for assessment of coronary endothelial function.

Volumetric arterial wall shear stress calculation based on cine phase contrast MRI

To assess the accuracy and precision of a volumetric wall shear stress (WSS) calculation method applied to cine phase contrast magnetic resonance imaging (PC-MRI) data. Volumetric WSS vectors were calculated in software phantoms. WSS algorithm parameters were optimized and the influence of spatial resolution and segmentation was evaluated. Subsequently, 2D cine PC-MRI data in the carotid and the aorta at varying spatial resolutions were obtained (n = 2) and compared with the simulations. Finally, volumetric WSS was calculated in 3D cine PC-MRI data of the carotid bifurcation and the aorta (n = 6). We found that at least 8 voxels across the diameter are required to obtain a WSS accuracy of 5% and a precision of 20% in software phantoms. Systematic WSS quantification errors up to 40% were found in the case of segmentation errors. The in vivo measurements using 2D cine PC-MRI exhibited WSS increase at increasing spatial resolutions, similar to the results in software phantoms. Volumetric WSS vectors were successfully calculated in three healthy carotid bifurcations and aortas. The effects of resolution and segmentation on the accuracy and precision of the WSS algorithm were quantified. We were able to calculate volumetric WSS in the carotid bifurcation and the aorta.

Correlation between systolic transvalvular flow and proximal aortic wall changes in bicuspid aortic valve stenosis

The purpose of this study was to analyse the correlation between preoperative systolic transvalvular flow patterns and proximal aortic wall lesions in patients undergoing surgery for bicuspid aortic valve (BAV) stenosis. A total of 48 consecutive patients with BAV stenosis (mean age 58 ± 9 years, 65% male) underwent aortic valve replacement (AVR) ± proximal aortic surgery from January 2012 through February 2013. Preoperative cardiac phase-contrast cine magnetic resonance imaging (MRI) assessment was performed in all patients in order to detect the area of maximal flow-induced stress in the proximal aorta. Based on these MRI data, two aortic wall samples (i.e. area of the maximal stress (jet sample) and the opposite aortic wall (control sample)) were collected during AVR surgery. Aortic wall changes were graded based on a summation of seven histological criteria (each scored from 0 to 3). Histological sum score (0-21) was separately calculated and compared between the two aortic samples (i.e. jet sample vs control sample). An eccentric transvalvular flow jet hitting the proximal aortic wall could be identified in all 48 (100%) patients. The mean histological sum score was significantly higher in the jet sample vs control sample areas of the aorta (i.e. 4.1 ± 1.8 vs 2.2 ± 1.5, respectively) (P = 0.02). None of the patients had a higher sum score value in the control sample. Our study demonstrates a strong correlation between the systolic pattern of the transvalvular flow jet and asymmetric proximal aortic wall changes in patients undergoing AVR for BAV stenosis.

Analysis of cerebrospinal fluid flow dynamics and morphology in Chiari I malformation with cine phase-contrast magnetic resonance imaging

To determine cerebrospinal fluid (CSF) dynamics and morphology in Chiari I malformation (CMI) and assess the response to surgery of the posterior cranial fossa, we examined midsagittal imaging along with anterior cervical 2-3 (AC2-3), posterior cervical 2-3 (PC2-3), and aqueduct CSF flow hydrodynamics in axial imaging by using cine phase-contrast magnetic resonance imaging (PCMR). We examined 52 patients with CMI, both with and without syringomyelia (SM), pre-/post-surgery, and compared them to 17 healthy volunteers. Statistical analyses included paired t-tests, independent-samples t-tests, binary logistic regression, and crosstab with MedCalc software. Patients with CMI had significantly shorter clivus length and larger tentorial angle than the healthy controls (P = 0.004, P = 0.019, respectively). The AC2-3 cranial/caudal peak velocity (PV), PC2-3 cranial/caudal PV and aqueduct cranial peak PV of patients with CMI were significantly lower than healthy volunteers pre-surgery (P = 0.034 AC2-3 cranial PV, P = 0.000002 AC2-3 caudal PV; P = 0.046 PC2-3 cranial PV, P = 0.015 PC2-3 caudal PV; P = 0.022 aqueduct cranial PV) and increased after surgery (P = 0.024 AC2-3 cranial PV, P = 0.002 AC2-3 caudal PV; P = 0.001 PC2-3 cranial PV, P = 0.032 PC2-3 caudal PV; P = 0.003 aqueduct cranial PV). The aqueduct caudal PV of patients with CMI was higher than that of healthy controls (P = 0.004) and decreased post-surgery (P = 0.012). Patients with pre-surgery PC2-3 cranial PV >2.63 cm/s and aqueduct cranial PV >2.13 cm/s, respectively, experienced primary symptom improvement after surgery. The innate bony dysontogenesis in patients with CMI contributes to tonsilar ectopia and exacerbates CSF flow obstruction. A pressure gradient that existed between SM and SAS supports the perivascular space theory that is used to explain SM formation. Our findings demonstrate that PCMR maybe a useful tool for predicting patient prognosis.

A new method for vessel segmentation based on a priori input from medical expertise in cine phase-contrast Magnetic Resonance Imaging

Background Phase contrast magnetic resonance imaging (PC-MRI) is the current gold standard for blood flow quantification. Using this technique it is possible to quantify cardiac output, stroke volume, shunts and valve insufficiencies. The accuracy of flow quantification is highly dependent on the manual delineation of the vessels of interest. Therefore, the purpose of this study is to develop an automatic method for vessel segmentation in PC-MRI sequences.

Third Ventriculostomy in Late-onset Idiopathic Aqueductal Stenosis Treatment: A Focus on Clinical Presentation and Radiological Diagnosis.

Endoscopic third ventriculostomy (ETV) is considered the gold standard treatment for obstructive hydrocephalus due to partial or complete obstruction of cerebrospinal fluid (CSF) ventricular pathways caused by mass lesions. However long-term efficacy of this procedure remains controversial as treatment of chronic adult hydrocephalus due to stenosis of Sylvian acqueduct [late-onset idiopathic aqueductal stenosis (LIAS)]. The authors describe clinical presentation, diagnostic investigations in patients affected by LIAS, and define their clinical and radiological outcome after ETV. From January 2003 to December 2008, 13 consecutive LIAS patients treated by ETV were retrospectively reviewed. Pre- and post-operative clinical and radiological findings, including conventional and phase-contrast (PC) cine magnetic resonance imaging (MRI) were investigated. ETV was successfully performed in all patients. Patient's neurological condition improved. No one required a second ETV procedure or shunt implantation. Clinical and radiological results reveal a satisfactory outcome of LIAS patients treated by ETV. At follow-up a clinical improvement could be demonstrated in all cases. Selection criteria of LIAS patients seem to be crucial to obtain satisfactory and long-lasting results. Even in elderly patients with chronic hydrocephalus, ETV can be considered the treatment of choice.

Detection of diminished response to cold pressor test in smokers: Assessment using phase-contrast cine magnetic resonance imaging of the coronary sinus

PurposeThe purposes of this study were to evaluate the reproducibility for measuring the cold pressor test (CPT)-induced myocardial blood flow (MBF) alteration using phase-contrast (PC) cine MRI, and to determine if this approach could detect altered MBF response to CPT in smokers. Materials and methodsAfter obtaining informed consent, ten healthy male non-smokers (mean age: 28±5 years) and ten age-matched male smokers (smoking duration ≥5 years, mean age: 28±3 years) were examined in this institutional review board approved study. Breath-hold PC cine MR images of the coronary sinus were obtained with a 3T MR imager with 32 channel coils at rest and during a CPT performed after immersing one foot in ice water. MBF was calculated as coronary sinus flow divided by the left ventricular (LV) mass which was given as a total LV myocardial volume measured on cine MRI multiplied by the specific gravity (1.05 g/mL). ResultsIn non-smokers, MBF was 0.86±0.25 mL/min/g at rest, with a significant increase to 1.20±0.36 mL/min/g seen during CPT (percentage change of MBF (∆MBF (%)); 39.2%±14.4%, p<0.001). Inter-study reproducibility for ∆MBF (%) measurements by different MR technologist was good, as indicated by the intraclass correlation coefficient of 0.93 and reproducibility coefficient of 10.5%. There was no significant difference between smokers and non-smokers for resting MBF (0.85±0.32 mL/min/g, p=0.91). However, ∆MBF (%) in smokers was significantly reduced (-4.0±32.2% vs. 39.2±14.4%, p=0.011). ConclusionPC cine MRI can be used to reproducibly quantify MBF response to CPT and to detect impaired flow response in smokers. This MR approach may be useful for monitoring the sequential change of coronary blood flow in various potentially pathologic conditions and for investigating its relationship with cardiovascular risk.

Relation of Thoracic Aortic Distensibility to Left Ventricular Area (from the Multi-Ethnic Study of Atherosclerosis [MESA

Decreased arterial compliance is an early manifestation of adverse structural and functional changes within the vessel wall. Its correlation with left ventricular (LV) area on computed tomography, a marker of LV remodeling, has not been well demonstrated. The aim of this study was to test the hypothesis that decreasing aortic compliance and increasing arterial stiffness are independently associated with increased LV area. The study population consisted of 3,540 patients (mean age 61 ± 10 years, 46% men) from the Multi-Ethnic Study of Atherosclerosis (MESA) who underwent aortic distensibility (AD) assessment on magnetic resonance imaging and LV area measurement on computed tomography (adjusted to body surface area). Multivariate logistic regression was performed to assess the association between body surface area-normalized LV area >75th percentile and AD after adjusting for baseline clinical, historical, and imaging covariates. Mean LV area index was 2,153 cm(2), and mean AD was 1.84 × 10(3) mm Hg(-1). Subjects in the lowest AD quartile were older, with higher prevalence rates of hypertension, diabetes, and hypercholesterolemia (p <0.05 for all comparisons). Using multivariate linear regression adjusting for demographics, traditional risk factors, coronary artery calcium, and C-reactive protein, each SD decrease was associated with an 18-cm(2) increase in LV area. In addition, decreasing AD quartiles were independently associated with increasing LV area index, defined as >75th percentile. In conclusion, in this multiethnic cohort, reduced AD was associated with increased LV area. Longitudinal studies are needed to determine if decreased distensibility precedes and directly influences increased LV area.

Carotid Artery Stiffness in Patients with Symptomatic Carotid Artery Disease with Contralateral Asymptomatic Carotid Artery Disease and in Patients with Bilateral Asymptomatic Carotid Artery Disease: A Cine Phase-contrast Carotid MR Study

Atherosclerosis is a systemic inflammatory disease that may affect multiple arterial beds simultaneously. Vascular distensibility is increasingly used in the clinical assessment of patients with atherosclerotic disease. In this study, we assess distensibility of symptomatic atherosclerotic carotid artery and of contralateral asymptomatic side. We also investigate the distensibility of bilaterally asymptomatic atherosclerotic carotid arteries using cine phase-contrast carotid magnetic resonance (MR) imaging. Nineteen patients with bilateral carotid artery disease underwent cine phase-contrast carotid imaging on a 1.5 T MR system. Ten patients had ipsilateral symptomatic carotid artery disease and contralateral asymptomatic stenosis. Nine additional patients with bilateral asymptomatic carotid artery disease constituted historical control group. Cine phase-contrast MR imaging acquired at the common carotid artery, maximum luminal stenosis, and internal carotid artery was used to determine carotid distensibility bilaterally for carotid arteries in both patient groups. Symptomatic carotid arteries were found to be significantly less distensible (mean distensibility coefficient [DC] 35.4 ± 6.12 × 10(-3)/kPa) than the contralateral asymptomatic vessels (mean DC 54.4 ± 7.88 × 10(-3)/kPa, P = .03) at the level of the common carotid artery. A similar trend of high distensibility for asymptomatic side in the area of maximum stenosis and the internal carotid artery was seen, but it was not found to be statistically significant. Plaque burden was comparable between the 2 groups at all locations. DC was comparable for patients with bilateral asymptomatic carotid artery stenoses. Distensibility of bilaterally asymptomatic carotid arteries was greater than that of asymptomatic carotid artery contralateral to the symptomatic side. Symptomatic carotid artery is stiffer than the contralateral asymptomatic side, despite comparable plaque burden. Patients with bilateral asymptomatic carotid artery disease have comparable stiffness. Larger studies are warranted to further investigate the findings of this MR study.

078 * CORRELATION BETWEEN SYSTOLIC TRANSVALVULAR FLOW AND PROXIMAL AORTIC WALL CHANGES IN BICUSPID AORTIC VALVE STENOSIS

OBJECTIVES: The purpose of this study was to analyse the correlation between preoperative systolic transvalvular flow patterns and proximal aortic wall lesions in patients undergoing surgery for bicuspid aortic valve (BAV) stenosis. METHODS: A total of 48 consecutive patients with BAV stenosis (mean age 58 ± 9 years, 65% male) underwent aortic valve replacement (AVR) ± proximal aortic surgery from January 2012 through February 2013. Preoperative cardiac phase-contrast cine magnetic resonance imaging (MRI) assessment was performed in all patients in order to detect the area of maximal flow-induced stress in the proximal aorta. Based on these MRI data, two aortic wall samples (i.e. area of the maximal stress ( jet sample) and the opposite aortic wall (control sample)) were collected during AVR surgery. Aortic wall changes were graded based on a summation of seven histological criteria (each scored from 0 to 3). Histological sum score (0–21) was separately calculated and compared between the two aortic samples (i.e. jet sample vs control sample). RESULTS: An eccentric transvalvular flow jet hitting the proximal aortic wall could be identified in all 48 (100%) patients. The mean histological sum score was significantly higher in the jet sample vs control sample areas of the aorta (i.e. 4.1 ± 1.8 vs 2.2 ± 1.5, respectively) (P = 0.02). None of the patients had a higher sum score value in the control sample. CONCLUSIONS: Our study demonstrates a strong correlation between the systolic pattern of the transvalvular flow jet and asymmetric proximal aortic wall changes in patients undergoing AVR for BAV stenosis.

Prospective analysis of transvalvular systolic flow and aortic wall changes in bicuspid aortic valve insufficiency

Methods A total of 76 consecutive patients with BAV disease (57±10 years, 71% male) underwent aortic valve replacement (AVR) ± proximal aortic surgery from January, 2012 through April, 2013. There was a subgroup of 58 (76%) patients with BAV stenosis (Group I), whereas the remaining 18 (14%) patients had isolated BAV insufficiency (Group II). Preoperative cardiac phase-contrast cinemagnetic resonance imaging (MRI) was performed in order to detect the area of maximal flow-induced stress in the proximal aorta. Based on MRI-data, two aortic wall samples i.e., area of the maximal stress (jet-sample) and the opposite aortic wall (control-sample) were collected during surgery. Aortic wall changes were graded based on 7 histological criteria (i.e., each from 0 to 3+) and were summarized in a sum-score. Histological sum-score (0 to 21+) was calculated and compared between samples (i.e., jetvs. control-sample).

Application of phase-contrast cine magnetic resonance imaging in endoscopic aqueductoplasty

The aim of this study was to evaluate the application of phase-contrast cine magnetic resonance imaging (MRI) in endoscopic aqueductoplasty (EA) for patients with obstructive hydrocephalus. The clinical diagnosis of hydrocephalus caused by aqueduct obstruction in 23 patients was confirmed by phase-contrast cine MRI examination. The patients were treated with EA and MRI was repeated during the follow-up. The cerebrospinal fluid (CSF) flow velocity in the aqueduct was measured to determine whether the aqueduct was obstructed. The results of phase-contrast cine MRI examinations indicated that there was no CSF flow in the aqueduct for all patients prior to surgery. Aqueductoplasty was successfully performed in all patients. The results of phase-contrast cine MRI examinations performed a week after surgery demonstrated an average CSF flow velocity of 4.74±1.77 cm/sec. During the follow-up, intracranial hypertension recurred in two patients in whom CSF flow was not observed in the aqueduct by the phase-contrast cine MRI scan. Aqueduct re-occlusion was revealed by an endoscopic exploration. By measuring the CSF flow velocity, phase-contrast cine MRI accurately identifies aqueduct obstruction. Cine MRI is a nontraumatic, simple and reliable method for determining whether the aqueduct is successfully opened following aqueductoplasty.

Total Anomalous Pulmonary Venous Connection in a 64-Year-Old Man: A Case Report

We report a 64-year-old man with incidentally found uncorrected total anomalous pulmonary venous connection (TAPVC). There have been only a few case reports of untreated TAPVC diagnosed after 60 years of age. Also, this is a first case report of TAPVC in which ECG-gated CT and phase-contrast cine magnetic resonance imaging (PC-MRI) was performed. He was referred to our hospital for the surgery of rectal cancer. He had been diagnosed to have an arterial septal defect (ASD) and persistent left superior vena cava (PLSVC), and Eisenmenger's syndrome was thought to be the cause of cyanosis at first. The vertical vein in TAPVC was initially misdiagnosed as PLSVC on enhanced axial CT images reconstructed with 5-mm slice thickness with gapless. ECG-gated CT and PC-MRI were useful to confirm the diagnosis. The vertical vein in TAPVC is morphologically similar to PLSVC. This kind of abnormality would be somewhat difficult to diagnose on non-ECG-gated CT, and might be misdiagnosed as a large ASD and PLSVC.

Impaired coronary flow reserve determined by MR measurement of coronary sinus flow predicts adverse outcome in patients with known or suspected coronary artery disease

Background Recent studies demonstrated that Rb PET-derived myocardial perfusion reserve has a significant prognostic impact on the prediction of cardiac events in patients assessed for myocardial ischemia. Regional myocardial ischemia and late gadolinium enhancement (LGE) defined by cardiac MR imaging are also reported as significant prognosticators for future cardiac events. However, the prognostic value of coronary flow reserve (CFR) obtained by MR flow measurement remains uncertain. The aim of this study was to evaluate the prognostic value of CFR determined by phase contrast cine MR imaging of the coronary sinus in patients with known or suspected coronary artery disease (CAD).

Predicting three‐dimensional patellofemoral kinematics from static imaging‐based alignment measures

Patellofemoral pain syndrome causes significant discomfort and disability among much of the general population. Despite recent breakthroughs in dynamic three-dimensional imaging technologies to assess pathological patellofemoral motion, such tools remain costly for clinical diagnostics applications. Thus, this study investigated whether three-dimensional patellofemoral kinematics could be predicted from routine two-dimensional static measures of patellofemoral joint alignment quantified from magnetic resonance imaging (MRI) data acquired in full knee extension. Twenty-six volunteers clinically diagnosed with patellofemoral pain (19 F/7 M, 25.9 ± 11.1 years) and 26 control subjects (19 F/7 M, 25.3 ± 7.7 years) were included in this IRB-approved study. Static three-dimensional sagittal T1-weighted gradient recall echo and dynamic MRI scans were acquired. For the dynamic image acquisition, subjects cyclically flexed and extended their knee (at 30 cycles/min) while a full cine-phase contrast MRI set (24 time frames of anatomic images and x-, y-, and z-velocity images) was acquired. From these data, static measures of patellofemoral alignment and three-dimensional patellofemoral kinematics were derived. Single and multiple regressions between static and kinematic variables were evaluated. Although shown reliable, the static MRI measures could only partially predict patellofemoral kinematics, with r(2) -values ranging from 16% to 77%. This makes it imperitave that the current precise, accurate, 3D, dynamic imaging techniques be translated into clinical tools.