Dataset Information

Nonenhanced MR angiography of the hand with flow-sensitive dephasing-prepared balanced SSFP sequence: initial experience with systemic sclerosis.

ABSTRACT: To compare the image quality and degree of vessel narrowing at flow-sensitive dephasing (FSD) magnetic resonance (MR) angiography of the hands with those at contrast material-enhanced MR angiography of the hands in patients with systemic sclerosis.In a single-center study with institutional review board approval and HIPAA compliance, six healthy volunteers and six patients with systemic sclerosis were imaged at 1.5-T nonenhanced FSD MR angiography followed by contrast-enhanced MR angiography. Sixteen vascular segments in four vessel groups were evaluated for image quality and assessed semiquantitatively for stenosis degree by using Likert scales. The nonparametric Wilcoxon signed rank test was used to perform pairwise comparisons of the MR angiographic techniques. P < .05 indicated statistical significance.Performing FSD MR angiography, as compared with time-resolved MR angiography and high-spatial-resolution MR angiography, improved the image quality for all arterial segments combined in the control (mean score, 2.9 [FSD] vs 3.7 [time-resolved technique] and 3.1 [high-spatial-resolution technique]) and patient (mean score, 4.0 [FSD] vs 4.2 [time-resolved technique] and 4.3 [high-spatial-resolution technique]) groups. In the control subjects, FSD angiography depicted proper digital artery stenosis that was less severe (mean grade, 0.7) than that seen with the time-resolved (mean grade, 1.6) and high-spatial-resolution (mean grade, 1.0) techniques. In the patient group, FSD angiography depicted lower degrees of stenosis, with a lower mean grade for all segments combined (1.3) compared with the corresponding mean grades for time-resolved (1.5) and high-spatial-resolution (1.8) MR angiography.Preliminary data indicate that the proposed nonenhanced FSD MR angiographic technique is an improvement over existing contrast-enhanced techniques for evaluation of the hand vasculature in vasospastic disorders of the hand. Further technical improvements and a systematic clinical study are warranted.

SUBMITTER: Sheehan JJ

PROVIDER: S-EPMC3064822 | biostudies-other | 2011 Apr

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:ObjectivesTo compare the image quality and diagnostic performance of two non-contrast enhanced MR angiography (NCE-MRA) techniques using flow-sensitive dephasing (FSD) prepared steady-state free precession (SSFP) and quiescent-interval single-shot (QISS) for the calf arteries in patients with diabetes.Materials and methodsTwenty six patients underwent the two NCE-MRA techniques followed by contrast-enhanced MRA (CE-MRA) of lower extremity on a 1.5T MR system. Image quality scores, arterial stenosis scores, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel sharpness, and diagnostic accuracy for detecting more than 50% arterial stenosis were evaluated and statistically compared using CE-MRA as the reference standard.ResultsAll examinations were performed successfully. Of the total 153 calf arterial segments obtained in the 26 patients, FSD and QISS showed no significant difference in the number of diagnostic arterial segments (151 [98%] vs. 147 [96%], respectively, P>0.05). The image quality of FSD was higher than that of QISS in the peroneal artery and posterior tibial artery (P<0.05), but no significant difference in the anterior tibial artery (P>0.05). SNR and CNR of FSD were higher than those of QISS (P<0.01), while FSD showed comparable vessel sharpness compared with QISS (P>0.05). The time efficiency of SNR and CNR between FSD and QISS showed no significant difference when taking into account the times for FSD-related scout scans. There was no difference in sensitivity (95% vs. 93%, P>0.05) and negative predictive value (98% vs. 97%, P>0.05) between FSD and QISS for detecting stenosis greater than 50%. However, FSD showed higher specificities (99% vs. 92%, P<0.05) and diagnostic accuracy (98% vs. 92%, P<0.05) compared to QISS.ConclusionBoth FSD and QISS had similar high sensitivity and negative predictive value for detecting calf arteries with over 50% stenosis, but FSD showed slightly higher diagnostic specificity and better depiction of arterial lesions due to its isotropic submillimeter spatial resolution. QISS, being an easier to use and less time-consuming technique, could be a method of choice for rapid screening of arterial disease of the lower extremity.

Project description:Differentiating benign from malignant peripheral nerve sheath tumors can be very challenging using conventional MR imaging. Our aim was to test the hypothesis that conventional and functional MR imaging can accurately diagnose malignancy in patients with indeterminate peripheral nerve sheath tumors.This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant study retrospectively reviewed 61 consecutive patients with 80 indeterminate peripheral nerve sheath tumors. Of these, 31 histologically proved peripheral nerve sheath tumors imaged with conventional (unenhanced T1, fluid-sensitive, contrast-enhanced T1-weighted sequences) and functional MR imaging (DWI/apparent diffusion coefficient mapping, dynamic contrast-enhanced MR imaging) were included. Two observers independently assessed anatomic (size, morphology, signal) and functional (ADC values, early arterial enhancement by dynamic contrast-enhanced MR) features to determine interobserver agreement. The accuracy of MR imaging for differentiating malignant from benign was also determined by receiver operating characteristic analysis.Of 31 peripheral nerve sheath tumors, there were 9 malignant (9%) and 22 benign ones (81%). With anatomic sequences, average tumor diameter (6.3 ± 1.8 versus 3.9 ± 2.3 mm, P = .009), ill-defined/infiltrative margins (77% versus 32%; P = .04), and the presence of peritumoral edema (66% versus 23%, P = .01) were different for malignant peripheral nerve sheath tumors and benign peripheral nerve sheath tumors. With functional sequences, minimum ADC (0.47 ± 0.32 × 10(-3) mm(2)/s versus 1.08 ± 0.26 × 10(-3) mm(2)/s; P < .0001) and the presence of early arterial enhancement (50% versus 11%; P = .03) were different for malignant peripheral nerve sheath tumors and benign peripheral nerve sheath tumors. The minimum ADC (area under receiver operating characteristic curve was 0.89; 95% confidence interval, 0.73-0.97) and the average tumor diameter (area under the curve = 0.8; 95% CI, 0.66-0.94) were accurate in differentiating malignant peripheral nerve sheath tumors from benign peripheral nerve sheath tumors. With threshold values for minimum ADC ? 1.0 × 10(-3) mm(2)/s and an average diameter of ?4.2 cm, malignancy could be diagnosed with 100% sensitivity (95% CI, 66.4%-100%).Average tumor diameter and minimum ADC values are potentially important parameters that may be used to distinguish malignant peripheral nerve sheath tumors from benign peripheral nerve sheath tumors.

Project description:The purpose of this study was to describe our experience with 1.0T MR-SIM including characterization, quality assurance (QA) program, and features necessary for treatment planning. Staffing, safety, and patient screening procedures were developed. Utilization of an external laser positioning system (ELPS) and MR-compatible couchtop were illustrated. Spatial and volumetric analyses were conducted between CT-SIM and MR-SIM using a stereotactic QA phantom with known landmarks and volumes. Magnetic field inhomogeneity was determined using phase difference analysis. System-related, in-plane distortion was evaluated and temporal changes were assessed. 3D distortion was characterized for regions of interest (ROIs) 5-20 cm away from isocenter. American College of Radiology (ACR) recommended tests and impact of ELPS on image quality were analyzed. Combined ultrashort echotime Dixon (UTE/Dixon) sequence was evaluated. Amplitude-triggered 4D MRI was implemented using a motion phantom (2-10 phases, ~ 2 cm excursion, 3-5 s periods) and a liver cancer patient. Duty cycle, acquisition time, and excursion were evaluated between maximum intensity projection (MIP) datasets. Less than 2% difference from expected was obtained between CT-SIM and MR-SIM volumes, with a mean distance of < 0.2 mm between landmarks. Magnetic field inhomogeneity was < 2 ppm. 2D distortion was < 2 mm over 28.6-33.6 mm of isocenter. Within 5 cm radius of isocenter, mean 3D geometric distortion was 0.59 ± 0.32 mm (maximum = 1.65 mm) and increased 10-15 cm from isocenter (mean = 1.57 ± 1.06 mm, maximum = 6.26 mm). ELPS interference was within the operating frequency of the scanner and was characterized by line patterns and a reduction in signal-to-noise ratio (4.6-12.6% for TE = 50-150 ms). Image quality checks were within ACR recommendations. UTE/Dixon sequences yielded detectability between bone and air. For 4D MRI, faster breathing periods had higher duty cycles than slow (50.4% (3 s) and 39.4% (5 s), p < 0.001) and ~fourfold acquisition time increase was measured for ten-phase versus two-phase. Superior-inferior object extent was underestimated 8% (6 mm) for two-phase as compared to ten-phase MIPs, although < 2% difference was obtained for ≥ 4 phases. 4D MRI for a patient demonstrated acceptable image quality in ~ 7 min. MR-SIM was integrated into our workflow and QA procedures were developed. Clinical applicability was demonstrated for 4D MRI and UTE imaging to support MR-SIM for single modality treatment planning.

Project description:Background and purposeThe cause of posterior reversible encephalopathy syndrome (PRES) is unknown. Two primary hypotheses exist: 1) hypertension exceeding auto-regulatory limits leading to forced hyper-perfusion and 2) vasoconstriction and hypo-perfusion leading to ischemia with resultant edema. The purpose of this study was to evaluate the catheter angiography (CA), MR angiography (MRA), and MR perfusion (MRP) features in PRES in order to render further insight into its mechanism of origin.Materials and methodsIn 47 patients with PRES, 9 CAs and 43 MRAs were evaluated for evidence of vasculopathy (vasoconstriction and vasodilation), and 15 MRP studies were evaluated for altered relative cerebral blood volume (rCBV) in PRES lesions and regions. Visualization of vessels on MRA and toxicity blood pressures were compared with the extent of hemispheric vasogenic edema.ResultsVasculopathy was present in 8 of 9 patients on CA (direct correlation to MRA in 3/6 patients). At MRA, moderate to severe vessel irregularity consistent with vasoconstriction and vasodilation was present in 30 of 43 patients and vessel pruning or irregularity in 7 patients, with follow-up MRA demonstrating reversal of vasoconstriction or vasodilation in 9 of 11 patients. Vasogenic edema was less in patients with hypertension compared with patients who were normotensive. Preserved normal length of the posterior cerebral artery (PCA) was commonly seen in patients with severe hypertension despite diffuse or focal vasoconstriction or vasodilation. In these patients, lengthier visualization of the distal PCA correlated with a lower grade of hemispheric edema (P = .002). Cortical rCBV was significantly reduced in 51 of 59 PRES lesions and regions compared with a healthy reference cortex (average 61% of reference cortex) with mild decrease in the remainder.ConclusionVasculopathy was a common finding on CA and MRA in our patients with PRES, and MRP demonstrated reduced cortical rCBV in PRES lesions. Vasogenic edema was reduced in patients with hypertension, and superior distal PCA visualization correlated with reduced hemispheric edema in patients with PRES and severe hypertension.

Project description:Systemic sclerosis (SSc) is an autoimmune disease initially recognized by hand involvement due to characteristic Raynaud's phenomenon (RP), puffy hands, skin thickening, and contractures resembling claw deformities. SSc contributes to hand impairment through inflammatory arthritis, joint contractures, tendon friction rubs (TFRs), RP, digital ulcers (DU), puffy hands, skin sclerosis, acro-osteolysis, and calcinosis. These manifestations, which often co-exist, can contribute to difficulty with occupational activities and activities of daily living (ADL), which can result in impaired quality of life. However, despite this knowledge, most diagnostic and treatment principles in SSc are focused on visceral manifestations due to known associations with morbidity and mortality. Treatment of inflammatory arthritis is symptom based and involves corticosteroids ?10mg daily, methotrexate, tumor necrosis factor inhibitors, tocilizumab, and abatacept. Small joint contractures are managed by principles of occupational hand therapy and rarely surgical procedures. TFRs may be treated similar to inflammatory arthritis with corticosteroids. All patients with RP and DU should keep digits covered and warm and avoid vasoconstrictive agents. Pharmacologic management of RP begins with use of calcium channel blockers, but additional agents that may be considered are fluoxetine and phosphodiesterase 5 (PDE5) inhibitors. DU management also involves vasodilators including calcium channel blockers and PDE5 inhibitors; bosentan has also been shown to prevent DU. In patients with severe RP and active DU, intravenous epoprostenol or iloprost can be used and surgical procedures, such as botulinum injections and digital sympathectomies, may be considered. For those with early diffuse cutaneous SSc needing immunosuppression for skin sclerosis, methotrexate or mycophenolate mofetil can be used, but the agent of choice depends on co-existing manifestations, such as inflammatory arthritis and/or lung involvement. Various pharmacologic agents for calcinosis have been considered but are generally ineffective; however, surgical options, including excision of areas of calcinosis, can be considered. Overall management of hand impairment for all patients with SSc should include occupational hand therapy techniques such as range of motion exercises, paraffin wax, and devices to assist in ADL. Thus, treatment options for the various manifestations contributing to hand impairment in SSc are limited and often modestly efficacious at best. Robust studies are needed to address the manifestations of SSc that contribute to hand impairment.

Dataset Information

Nonenhanced MR angiography of the hand with flow-sensitive dephasing-prepared balanced SSFP sequence: initial experience with systemic sclerosis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets