scholarly journals Accelerated acquisition of carotid MR angiography using 3D gradient-echo imaging with two-point Dixon

2020 ◽  
Vol 62 (10) ◽  
pp. 1345-1349
Author(s):  
Ryusuke Irie ◽  
Shiori Amemiya ◽  
Tsuyoshi Ueyama ◽  
Yuichi Suzuki ◽  
Kouhei Kamiya ◽  
...  
Keyword(s):  
Signal Intensity ◽  
Intensity Ratio ◽  
Mr Angiography ◽  
Carotid Bifurcation ◽  
Visual Assessment ◽  
Signal Intensity Ratio ◽  
Scan Time ◽  
Signal Change ◽  
Significant Difference ◽  
Gradient Echo Imaging

Abstract This pilot study tests the feasibility of rapid carotid MR angiography using the liver acquisition with volume acceleration-flex technique (LAVA MRA). Seven healthy volunteers and 21 consecutive patients suspected of carotid stenosis underwent LAVA and conventional time-of-flight (cTOF) MRAs. Artery-to-fat and artery-to-muscle signal intensity ratios were manually measured. LAVA MRA exhibited a significantly larger artery-to-fat signal intensity ratio compared with cTOF MRA in all slices (P < 0.001) and exhibited a larger (P < 0.001) or equivalent (P = 1.0) artery-to-muscle signal intensity ratio in the extracranial carotid arteries. The image quality of the cervical carotid bifurcation and the signal change on each MRA were visually assessed and compared among the MRAs. There was no significant difference between the two MRAs in visual assessment. LAVA MRA can provide visualization similar to cTOF MRA in the evaluation of the cervical carotid bifurcation while reducing scan time by one-fifth.

scholarly journals Signal intensity ratio of draining vein on silent MR angiography as an indicator of high-flow arteriovenous shunt in brain arteriovenous malformation

2021 ◽  
Author(s):  
Chun-Xue Wu ◽  
Zhen-Xiang Zang ◽  
Tao Hong ◽  
Meng-Qi Dong ◽  
Yi Shan ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Digital Subtraction Angiography ◽  
Transit Time ◽  
Signal Intensity ◽  
Intensity Ratio ◽  
Mr Angiography ◽  
High Flow ◽  
Signal Intensity Ratio ◽  
Digital Subtraction ◽  
Brain Arteriovenous Malformation

Abstract Objectives To evaluate whether the signal intensity ratio (rSI) of the draining vein on silent MR angiography is correlated with arteriovenous (A–V) transit time on digital subtraction angiography (DSA), thereby identifying high-flow A–V shunt in brain arteriovenous malformation (BAVM), and to analyze whether the rSI and the characteristic of draining veins on silent MRA are associated with hemorrhage presentation. Methods Eighty-one draining veins of 46 participants with BAVM (mean age 33.2 ± 16.9 years) who underwent silent MRA and DSA were evaluated retrospectively. The correlation between the rSI of the draining vein on silent MRA and A–V transit time on DSA was examined. The AUC-ROC was obtained to evaluate the performance of the rSI in determining the presence of high-flow A–V shunt. The characteristics of draining veins with the maximum rSI (rSImax) were further compared between the hemorrhagic and non-hemorrhagic untreated BAVM. Results The rSI of each draining vein on silent MRA was significantly correlated with A–V transit time from DSA (r = −0.81, p < .001). The AUC-ROC was 0.89 for using the rSI to determine the presence of high-flow A–V shunt. A cut-off rSI value of 1.09 yielded a sensitivity of 82.4% and a specificity of 82.8%. The draining vein with rSImax and no ectasia was significantly more observed in the hemorrhagic group (p = 0.045). Conclusions The rSI of the draining vein on silent MRA is significantly correlated with A–V transit time on DSA, and it can be used as an indicator of high-flow A–V shunt in BAVM. Key Points • The signal intensity ratio (rSI) of the draining vein on silent MRA significantly correlated with arteriovenous (A–V) transit time of brain arteriovenous malformation (BAVM) on digital subtraction angiography (DSA). • The area under the receiver operating characteristic curve (AUC) was 0.89 for using the rSI of draining veins to determine high-flow A–V shunt. • Draining veins with maximum rSI and no ectasia were significantly more observed in the hemorrhagic group of BAVM (p = 0.045).

scholarly journals A Comparative Analysis of DWI and Ultrasound in Thyroid Nodules

2019 ◽  
Author(s):  
Wei dan Kong ◽  
Xiu hui Yue ◽  
Ji liang Ren ◽  
Xiao feng Tao
Keyword(s):  
Sensitivity And Specificity ◽  
Signal Intensity ◽  
Intensity Ratio ◽  
Diffusion Weighted Imaging ◽  
Thyroid Nodules ◽  
Signal Intensity Ratio ◽  
Adc Value ◽  
Diffusion Weighted ◽  
Significant Difference ◽  
Sensitivity Specificity

Abstract Background Diffusion weighted imaging and ultrasound are commonly used methods to examine thyroid nodules, but their comparative value is rarely studied. To evaluate the value of diffusion weighted imaging and ultrasound in differentiing benign and malignant thyroid nodules Methods A total of 100 patients with 137 nodules were enrolled. who underwent both diffusion weighted imaging and ultrasound before operation. T1 and T2 signal intensity ratio (SIR) of each thyroid nodule was calculated by measuring the mean signal intensity divided by that of paraspinal muscle. The value of ADC,signal intensity ratio (SIR) of benign and malignant thyroid nodules were analyzed by two independent sample t test. The sensitivity, specificity and accuracy of DWI and ultrasound were compared and analyzed by chi-square test. Results There was no significant difference in signal intensity ratio between benign and malignant thyroid nodules. The ADC value had significant difference. When the threshold value was 1.12 ×10-3 mm2/s, the maximum area under the curve was 0.944,The sensitivity, specificity and accuracy were 84.9%, 92.2% and 87.6% respectively. The sensitivity and specificity of ultrasound diagnosis were 90.1%, 80.4% and 86.9% respectively. Conclusion Ultrasound has high sensitivity in differentiating benign and malignant thyroid nodules, and ADC value has high specificity in differentiating thyroid nodules, but there is no statistical difference in sensitivity and specificity between the two. DWI and Ultrasound have their own advantages in differentiating benign and malignant thyroid nodules.

Comparison of Biomechanical and Anatomical Effects Following Eccentric and Concentric Exertions

2005 ◽  
Vol 49 (14) ◽  
pp. 1287-1291
Author(s):  
Amrish O. Chourasia ◽  
Mary E. Sesto ◽  
Youngkyoo Jung ◽  
Robert S. Howery ◽  
Robert G. Radwin
Keyword(s):  
Signal Intensity ◽  
Intensity Ratio ◽  
Maximum Voluntary Contraction ◽  
Magnetic Resonance Images ◽  
Voluntary Contraction ◽  
Work Place ◽  
Signal Intensity Ratio ◽  
Mechanical Stiffness ◽  
Average Decrease ◽  
Muscle Shortening

Work place exertions may include muscle shortening (concentric) or muscle lengthening (eccentric) contractions. This study investigates the upper limb mechanical properties and magnetic resonance images (MRI) of the involved muscles following submaximal eccentric and concentric exertions. Twelve participants were randomly assigned to perform at 30° per second eccentric or concentric forearm supination exertions at 50% isometric maximum voluntary contraction (MVC) for 30 minutes. Measurement of mechanical stiffness, isometric MVC, localized discomfort and MRI supinator: extensor signal intensity ratio was done before, immediately after, 1 hour after and 24 hours after the bout of exercise. A 53% average decrease in mechanical stiffness after 1 hour was observed for the eccentric group (p< 0.05) compared to a 1% average decrease for the concentric group (p> 0.05). Edema, indicative of swelling, was observed 24 hrs after exercise, with an average increase in the MRI supinator: extensor signal intensity ratio of 36% for the eccentric group and less than 10% for the concentric group (p<0.05).

Minimizing table time in patients with claustrophobia using focused ferumoxytol-enhanced MR angiography (f-FEMRA): a feasibility study

2021 ◽  
Vol 94 (1125) ◽  
pp. 20210430
Author(s):  
Puja Shahrouki ◽  
Kim-Lien Nguyen ◽  
John M. Moriarty ◽  
Adam N. Plotnik ◽  
Takegawa Yoshida ◽  
...  
Keyword(s):  
Image Quality ◽  
Mr Angiography ◽  
Signal To Noise Ratio ◽  
Diagnostic Image Quality ◽  
Diagnostic Confidence ◽  
Motion Artefact ◽  
Scan Time ◽  
Wilcoxon Rank Sum Test ◽  
Significant Difference ◽  
Noise Ratio

Objectives: To assess the feasibility of a rapid, focused ferumoxytol-enhanced MR angiography (f-FEMRA) protocol in patients with claustrophobia. Methods: In this retrospective study, 13 patients with claustrophobia expressed reluctance to undergo conventional MR angiography, but agreed to a trial of up to 10 min in the scanner bore and underwent f-FEMRA. Thirteen matched control patients who underwent gadolinium-enhanced MR angiography (GEMRA) were identified for comparison of diagnostic image quality. For f-FEMRA, the time from localizer image acquisition to completion of the angiographic acquisition was measured. Two radiologists independently scored images on both f-FEMRA and GEMRA for arterial and venous image quality, motion artefact and diagnostic confidence using a 5-point scale, five being best. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the aorta and IVC were measured. The Wilcoxon rank-sum test, one-way ANOVA with Tukey correction and two-tailed t tests were utilized for statistical analyses. Results: All scans were diagnostic and assessed with high confidence (scores ≥ 4). Average scan time for f-FEMRA was 6.27 min (range 3.56 to 10.12 min), with no significant difference between f-FEMRA and GEMRA in diagnostic confidence (4.86 ± 0.24 vs 4.69 ± 0.25, p = 0.13), arterial image quality (4.62 ± 0.57 vs 4.65 ± 0.49, p = 0.78) and motion artefact score (4.58 ± 0.49 vs 4.58 ± 0.28, p > 0.99). f-FEMRA scored significantly better for venous image quality than GEMRA (4.62 ± 0.42 vs 4.19 ± 0.56, p = 0.04). CNR in the IVC was significantly higher for steady-state f-FEMRA than GEMRA regardless of the enhancement phase (p < 0.05). Conclusions: Comprehensive vascular MR imaging of the thorax, abdomen and pelvis can be completed in as little as 5 min within the magnet bore using f-FEMRA, facilitating acceptance by patients with claustrophobia and streamlining workflow. Advances in knowledge: A focused approach to vascular imaging with ferumoxytol can be performed in patients with claustrophobia, limiting time in the magnet bore to 10 min or less, while acquiring fully diagnostic images of the thorax, abdomen and pelvis.

Abstract T P28: Brain MRI FLAIR Signal Intensity Ratio Is Correlated With Matrix Metalloproteinase-9 Level In Acute Ischemic Stroke

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Ruchira M Jha ◽  
Thomas W Battey ◽  
Ly Pham ◽  
Hannah Irvine ◽  
Karen Furie ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Acute Stroke ◽  
Signal Intensity ◽  
Intensity Ratio ◽  
Brain Mri ◽  
Hemorrhagic Transformation ◽  
Signal Intensity Ratio ◽  
Blood Samples ◽  
The Mean ◽  
Metalloproteinase 9

Introduction: Increased Matrix Metalloproteinase-9 (MMP9) level is associated with symptomatic hemorrhagic transformation (HT) after stroke. Higher risk of HT has also been reported in patients with early FLAIR hyperintensity on brain MRI. Hypothesis: We assessed whether FLAIR hyperintensity is associated with MMP9 levels. Methods: We retrospectively analyzed a cohort of acute stroke subjects who had acute brain MRI images and blood samples within the first 12 hours after onset of stroke. FLAIR hyperintensity was quantitatively assessed using FLAIR signal intensity ratio between the stroke lesion and corresponding normal contralateral hemispheres. For each subject, the FLAIR ratio was generated from the average of 6 regions of interest: 2 white matter and 2 gray matter regions each on 2 separate slices. MMP9 was measured using standard ELISA technique. Univariate and multivariate analyses were used to evaluate the relationship between FR and MMP9 and clinical covariates. Results: 180 subjects had brain MRI and MMP9 available for analysis. MRI occurred within 6 ±3 hours and blood samples were drawn within 7 ± 4 hours from last seen well time. The mean MMP9 level was 238 ± 242 ng/mL and the mean FLAIR ratio was 1.40± 0.23. In univariate analysis, FLAIR ratio was associated with time to MRI (r= 0.18, p=0.01) and MMP9 (r=0.29, p<0.001). In multivariate analysis both FLAIR ratio (p<0.001) and time to MRI (p=0.003) remained associated with MMP9. Conclusions: There is a significant association between FLAIR ratio and MMP9 in acute stroke subjects. This raises the possibility that FLAIR hyperintensity reflects blood brain barrier changes during ischemia. Future studies to validate the prognostic value of FLAIR ratio in predicting symptomatic hemorrhagic transformation are warranted.

scholarly journals Quantitative Analysis of Apoptotic Cell Death Using Proton Nuclear Magnetic Resonance Spectroscopy

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3778-3786 ◽  
Author(s):  
Francis G. Blankenberg ◽  
Peter D. Katsikis ◽  
Richard W. Storrs ◽  
Christian Beaulieu ◽  
Daniel Spielman ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Cell Death ◽  
Magnetic Resonance ◽  
1H Nmr ◽  
Signal Intensity ◽  
Intensity Ratio ◽  
Apoptotic Cell ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Signal Intensity Ratio

Abstract Quantification of apoptotic cell death in vivo has become an important area of investigation in patients with acute lymphoblastic leukemia (ALL). We have devised a noninvasive analytical method to estimate the percentage of apoptotic lymphoblasts in doxorubicin-treated Jurkat T-cell ALL cultures, using proton nuclear magnetic resonance spectroscopy (1H NMR). We have found that the ratio of the methylene (CH2 ) resonance (at 1.3 ppm) to the methyl (CH3 ) resonance (at 0.9 ppm) signal intensity, as observed by 1H NMR, is directly proportional to the percentage of apoptotic lymphoblasts in vitro. The correlation between the CH2/CH3 signal intensity ratio and the percentage of apoptotic lymphoblasts was optimal 24 to 28 hours after doxorubicin treatment (r2 = .947, N = 27 samples). There was also a direct temporal relationship between an increase in the CH2/CH3 signal intensity ratio and the onset of apoptosis as detected by nuclear morphologic analysis, fluorescein-annexin V flow cytometry, and DNA gel electrophoresis. Thin-layer chromatography confirmed that a dynamic and/or compositional change of the plasma membrane, rather than increases in lipase activity or fatty acid production, appears to account for the increase in the CH2/CH3 signal intensity ratio during apoptosis. 1H NMR may have clinical utility for the early noninvasive assessment of chemotherapeutic efficacy in patients with ALL.

scholarly journals Apparent Diffusion Coefficient Signal Intensity Ratio Predicts the Effect of Revascularization on Ischemic Cerebral Edema

2018 ◽  
Vol 45 (3-4) ◽  
pp. 93-100 ◽  
Author(s):  
Matthew B. Bevers ◽  
Thomas W.K. Battey ◽  
Ann-Christin Ostwaldt ◽  
Reza Jahan ◽  
Jeffrey L. Saver ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Apparent Diffusion Coefficient ◽  
Cerebral Edema ◽  
Signal Intensity ◽  
Intensity Ratio ◽  
Response To Therapy ◽  
Signal Intensity Ratio ◽  
Edema Formation ◽  
Post Stroke ◽  
Apparent Diffusion

Background: Apparent diffusion coefficient (ADC) imaging is a biomarker of cytotoxic injury that predicts edema formation and outcome after ischemic stroke. It therefore has the potential to serve as a “tissue clock” to describe the extent of ischemic injury and potentially predict response to therapy. The goal of this study was to determine the relationship between baseline ADC signal intensity, revascularization, and edema formation. Methods: We examined the ADC signal intensity ratio (ADCr) of the stroke lesion (defined as the baseline DWI hyperintense region) compared to the contralateral normal hemisphere in 65 subjects from the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy trial. The associations between ADCr, neurologic outcome, and cerebral edema were examined. Finally, we explored the interaction between baseline ADCr and vessel recanalization at day 7 on post-stroke edema. Results: We found that lower initial ADCr was associated with a worse outcome on the modified Rankin Scale (mRS) at 90 days (52.2% of those with ADCr <64% were mRS 5–6 vs. 19.1% with ADCr ≥64%, p = 0.006). Those subjects with reconstitution of flow distal to the initial vessel occlusion showed greater normalization of ADCr on follow-up scan (increase in ADCr of 16.4 ± 2.07 vs. 1.99 ± 4.33%, p = 0.0039). In those patients with low baseline ADCr, successful revascularization was associated with reduced edema (median swelling volume 164 mL [interquartile range (IQR) 53.3–190 mL] vs. 20.7 mL [IQR 3.20–55.1 mL], p = 0.024). Conclusions: This study reaffirms the association of ADCr with outcome after stroke, supports the idea that reperfusion may attenuate rather than enhance post-stroke edema, and indicates that the degree of edema with and without revascularization may be predicted by ADCr.

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