Application of Magnetization-prepared True Fast Imaging with Steady-state Precession Sequence in Brain Tumor Enhancement / 中国医学科学院学报

Objective To evaluate the application of two-dimensional magnetization-prepared true fast imaging with steady-state precession(2D-MP-TrueFISP)sequence in brain tumor enhancement.Methods In this study,60 cases of brain tumor patients who underwent enhanced magnetic resonance imaging of brain were scanned with 2D-MP-TrueFISP/two-dimensional spoiled gradient-recalled echo(2D-SPGR)before and after enhancement.The scores of lesions on the images of 2D-MP-TrueFISP/2D-SPGR were compared.At the same level of 2D-SPGE and 2D-MP-TrueFISP,the signal intensities(SIs)of lesions,white matter,and cerebrospinal fluid were measured before and after enhancement,and the contrast ratios(CRs)of lesions were calculated.The CRs before and after 2D-SPGR/2D-MP-TrueFISP enhancement and those between 2D-SPGR and 2D-MP-TrueFISP after enhancement were compared.Results The scores of lesions after 2D-MP-TrueFISP/2D-SPGR T1WI enhancement were 9.0(9.0,9.0)and 7.0(6.0,7.0),respectively,with significant difference(

Balanced steady-state free precession MRA for diagnosing renal artery stenosis: Meta-analysis / 中国介入影像与治疗学

Objective" To investigate the value of balanced steady-state free precession (B-SSFP) MRA for diagnosing renal artery stenosis (RAS) with Meta-analysis. Methods PubMed, EMbase and Cochrane Library databases were searched. English studies assessed B-SSFP MRA diagnostic performance in RAS patients were reviewed. Quality assessment was conducted by adopting the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. Statistical analysis was adopted using the software of Meta Disc 1.4 and Stata 12.0. The summary ROC (SROC) curve was drawn, and pooled AUC, sensitivity, specificity, diagnostic odds ratio were calculated. Results A total of 12 articles including 21 results were enrolled, which had highly heterogeneous by using random effects models. In B-SSFP diagnosing RAS, meta-analysis showed the pooled sensitivity was 0.85 (95%CI [0.81, 0.88], I2=56.8%) and pooled specificity was 0.96 (95% CI [0.95, 0.97], I2=85.3%), the area under the SROC curve was 0.964 4, the pooled diagnostic odds ratio was 137.94 (95%CI [84.75, 224.50]). Regression analysis showed that heterogeneity may be derived from the year of publication (P=0.038). Conclusion: B-SSFP MRA is accurate and reliable for diagnosing RAS, and may be the first choice in patients with renal insufficiency.

Diagnostic Performance of Diffusion-Weighted Steady-State Free Precession in Differential Diagnosis of Neoplastic and Benign Osteoporotic Vertebral Compression Fractures: Comparison to Diffusion-Weighted Echo-Planar Imaging

PURPOSE: To evaluate the diagnostic performance of diffusion-weighted steady-state free precession (DW-SSFP) in comparison to diffusion-weighted echo-planar imaging (DW-EPI) for differentiating the neoplastic and benign osteoporotic vertebral compression fractures. MATERIALS AND METHODS: The subjects were 40 patients with recent vertebral compression fractures but no history of vertebroplasty, spine operation, or chemotherapy. They had received 3-Tesla (T) spine magnetic resonance imaging (MRI), including both DW-SSFP and DW-EPI sequences. The 40 patients included 20 with neoplastic vertebral fracture and 20 with benign osteoporotic vertebral fracture. In each fracture lesion, we obtained the signal intensity normalized by the signal intensity of normal bone marrow (SI norm) on DW-SSFP and the apparent diffusion coefficient (ADC) on DW-EPI. The correlation between the SI norm and the ADC in each lesion was analyzed using linear regression. The optimal cut-off values for the diagnosis of neoplastic fracture were determined in each sequence using Youden's J statistics and receiver operating characteristic curve analyses. RESULTS: In the neoplastic fracture, the median SI norm on DW-SSFP was higher and the median ADC on DW-EPI was lower than the benign osteoporotic fracture (5.24 vs. 1.30, P = 0.032, and 0.86 vs. 1.48, P = 0.041, respectively). Inverse linear correlations were evident between SI norm and ADC in both neoplastic and benign osteoporotic fractures (r = −0.45 and −0.61, respectively). The optimal cut-off values for diagnosis of neoplastic fracture were SI norm of 3.0 in DW-SSFP with the sensitivity and specificity of 90.4% (95% confidence interval [CI]: 81.0–99.0) and 95.3% (95% CI: 90.0–100.0), respectively, and ADC of 1.3 in DW-EPI with the sensitivity and specificity of 90.5% (95% CI: 80.0–100.0) and 70.4% (95% CI: 60.0–80.0), respectively. CONCLUSION: In 3-T MRI, DW-SSFP has comparable sensitivity and specificity to DW-EPI in differentiating the neoplastic vertebral fracture from the benign osteoporotic vertebral fracture.

Non-contrast-enhanced MR Angiography of Hand：Preliminary Clinical Experience / 中国医学影像学杂志

Purpose To assess the clinical application of non-contrast-enhanced MR angiography (NCE-MRA) using flow sensitive dephasing (FSD) prepared steady-state free precession (SSFP) for displaying hand arteries of patients with rheumatoid arthritis. Materials and Methods Twenty-two patients with rheumatoid arthritis were recruited in this study. All the patients undertook hand NCE-MRA and three-dimensional dynamic CE-MRA on a 1.5T MR scanner. The informed consent was obtained from each subject. Image quality was assessed independently by two experienced radiologists at three arterial segments (wrist arteries, palm arteries, andfinger arteries) with a four-point scale. Signal to noise ratio (SNR), contrast to noise ratio (CNR), and vessel sharpness were evaluated by a magnetic resonance physicist. The results and image quality were statistically compared between the two MRA techniques.Results Twenty-two patients of 24 hands successfully underwent NCE-MRA and CE-MRA scan. Among 72 vascular segments, 69 segments of NCE-MRA were diagnostic, which was higher than that of CE-MRA (96% vs 83%,P<0.05). Otherwise, the image quality, SNR, CNR and vessel sharpness of NCE-MRA were all superior to those of CE-MRA (P<0.05).Conclusion NCE-MRA using FSD-prepared SSFP allows clear depiction of the hand arterial tree, and the image quality is superior to that of dynamic CE-MRA. It is a potential tool for evaluating the disease of hand arteries.

3D Whole-Heart Coronary MR Angiography at 1.5T in Healthy Volunteers: Comparison between Unenhanced SSFP and Gd-Enhanced FLASH Sequences

OBJECTIVE: To validate the optimal cardiac phase and appropriate acquisition window for three-dimensional (3D) whole-heart coronary magnetic resonance angiography (MRA) with a steady-state free precession (SSFP) sequence, and to compare image quality between SSFP and Gd-enhanced fast low-angle shot (FLASH) MR techniques at 1.5 Tesla (T). MATERIALS AND METHODS: Thirty healthy volunteers (M:F = 25:5; mean age, 35 years; range, 24-54 years) underwent a coronary MRA at 1.5T. 3D whole-heart coronary MRA with an SSFP was performed at three different times: 1) at end-systole with a narrow (120-msec) acquisition window (ESN), 2) mid-diastole with narrow acquisition (MDN); and 3) mid-diastole with wide (170-msec) acquisition (MDW). All volunteers underwent a contrast enhanced coronary MRA after undergoing an unenhanced 3D true fast imaging with steady-state precession (FISP) MRA three times. A contrast enhanced coronary MRA with FLASH was performed during MDN. Visibility of the coronary artery and image quality were evaluated for 11 segments, as suggested by the American Heart Association. Image quality was scored by a five-point scale (1 = not visible to 5 = excellent). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were evaluated at the proximal coronary arteries. RESULTS: The SSFP sequence rendered higher visibility coronary segments, higher image quality, as well as higher SNR and CNR than the Gd-enhanced FLASH technique at 1.5T (p < 0.05). The visibility of coronary segments, image quality, SNR and CNR in the ESN, MDN and MDW with SSFP sequence did not differ significantly. CONCLUSION: An SSFP sequence provides an excellent method for the 3D whole-heart coronary MRA at 1.5T. Contrast enhanced coronary MRA using the FLASH sequence does not help improve the visibility of coronary segments, image quality, SNR or CNR on the 3D whole-heart coronary MRA.

A study of arteries of foot by flow sensitive dephasing prepared balanced steady-state free precession MR angiography in diabetes / 中华放射学杂志

Objective To investigate balanced steady-state free precession with flow-sensitive dephasing magnetization preparation (FSD-bSSFP) in the assessment of arteries of foot in diabetic patients.Methods The lower-extremity peripheral arteries of 43 diabetic patients were evaluated by FSD-bSSFP no contrast MRA and contrast-enhanced MRA (CE-MRA)in. Two experienced observers assessed the image quality, degree of venous contaminated and visibility of pedal artery branches by FSD-bSSFP and CE-MRA respectively in consensus. The signal intensity( SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the source images of both groups were measured and Wilcoxon and t tests were performed. Results The image score of FSD-bSSFP group was 2.7 ± 1.1 and CE-MRA was 2.6 ± 0.8, there was no statistical difference ( Z = 0. 134, P ＞ 0. 05 ). The image score of demonstration of the pedal artery branches and degree of venous contamination on FSD-bSSFP were 3.2 ± 0. 9 and 1.8 ± 0. 4 respectively which were superior to that of CE-MRA (2.5 ± 0.9 and 2.1 ± 0.8 respectively). Significant statistical difference existed between the two groups in demonstration of pedal artery branches ( Z = 5.246, P ＜ 0.05 ) and degree of venous contamination (Z =2.541 ,P ＜0.05). SNR of FSD-bSSFP was 148.6 ±26.7, CNR was 88.3 ± 19.0. SNR of CE-MRA was 148.5 ± 45.6, CNR was 121.0 ± 41.0. No statistical difference existed between SNR between two methods (t = 0.013, P ＞ 0.05 ). But CNR of CE-MRA was superior to that of FSD-bSSFP and significant statistical difference existed between these two methods ( t = 5.113, P ＜ 0.01 ). Conclusion FSD-bSSFP without contrast could be used in the evaluation of foot arteries in patients of renal dysfunction and diabetes.