T1 Mapping for Differentiating of Haemorrhagic Transformation from Extravasation of Iodine Contrast Agents: A Phantom Study.

OBJECTIVE: To evaluate T1 mapping values in different concentrations of iodine and mixed blood and to simulate the application of T1 mapping in differentiating iodine contrast extravasation and haemorrhage transformation after revascularisation in acute ischemic stroke. STUDY DESIGN: A phantom-based experimental study. Place and Duration of the Study: Department of Radiology, the Second Affiliated Hospital of Soochow University, China, from October 2020 to December 2021. METHODOLOGY: Fresh blood, pure iodine, blood-iodine mixtures (75/25, 50/50, and 25/75 ratios), and diluted iodine (at a concentration of 2.1 mmol I/L) were scanned in a phantom on 3-T MR T1 mapping imaging. A total of 10 layers in the middle section of tubes were scanned. The mean value of T1 mapping and 95% confidence interval for the investigated sample compositions were calculated and compared by ANOVA. RESULTS: The mean values (95% CI) for fresh blood, [2/3] blood +[1/3] iodine, [1/2] blood +[1/2] iodine, [1/3] blood +[2/3] iodine, and pure iodine were 2108.69 ± 1966.68-2250.71(ms), 1991.72 ± 1763.22-2220.21(ms), 1811.62 ± 1614.79-2008.45(ms), 1624.39 ± 1442.41-1806.37(ms), 1294.68 ± 1172.92-1416.44(ms), respectively. The differences between the T1 mapping values of all compositions were significant (p <0.01), except for fresh blood and the sample consisting of 67% blood. The mean value on T1 mapping (95% CI) was 1294.68 ± 1172.92-1416.44 (ms) in the samples only with diluted iodine, which was significantly different from other investigated samples (p <0.01). The intra-class correlation coefficient between the two times drawing of radiologist A was excellent (ICC=0.913, p<0.01), and between radiologists A and B was 0.99. CONCLUSION: Iodine contrast extravasation in a phantom setting might be distinguished from haemorrhagic transformation using T1 mapping. KEY WORDS: Acute ischemic stroke, Haemorrhage transformation, Contrast extravasation, Magnetic resonance imaging, T1 mapping, 3T MRI.

Detection of the disease activity with ankylosing spondylitis through intravoxel incoherent motion diffusion-weighted MR imaging of sacroiliac joint.

OBJECTIVE: To explore the value of the quantitative parameter of intravoxel incoherent motion diffusion (IVIM-DWI) at 3.0 T MRI of the sacroiliac joint in differentiating different disease activity statuses of ankylosing spondylitis (AS) and to compare it with traditional diffusion-weighted imaging (DWI) and Spondyloarthritis Research Consortium of Canada (SPARCC) score. METHODS: 56 AS patients (active group, inactive group) and 24 healthy controls were included. Clinical data, quantitative parameters of IVIM-DWI MR images and the SPARCC scores were collected. The Kruskal-Wallis test was used to compare the differences between the groups. Receiver operating characteristic (ROC) curve analysis of histogram data and the SPARCC scores identified the efficacy of the three groups. The Spearman correlation coefficients were used to analyse the correlation between the quantitative IVIIM-DWI parameters and the SPARCC score. RESULTS: The f (10th percentile) and SPARCC score of the active group were significantly higher than those of the inactive group. The f (10th, 25th, 50th percentiles), Dslow (average, entropy, 10th ~ 90 th percentiles), Dfast (kurtosis, skewness), ADC (average, 10th ~ 90 th percentiles) and the SPARCC score of the active group were significantly higher than the control group (p < 0.05). The AUC of the SPARCC score was the highest (0.799) in the identification between the active and inactive groups, and the sensitivity and specificity were 69.23 and 82.35%, respectively, at the cut-off value of 12. The SPARCC score was positively correlated with each percentile and the average value. CONCLUSIONS: Quantitative IVIIM-DWI parameters are helpful for the identification of different AS disease activity levels and are superior to traditional DWI. IVIM-DWI quantitative parameters had a good correlation with the SPARCC score. ADVANCES IN KNOWLEDGE: A new MR technology-quantitative parameters of IVIM-DWI contribute to the identification of AS disease activity. IVIM-DWI quantitative parameters were well correlated with the SPARCC score.

Association Between Small Vessel Disease Markers, Medial Temporal Lobe Atrophy and Cognitive Impairment After Stroke: A Systematic Review and Meta-Analysis.

OBJECTIVES: Two-thirds of stroke survivors suffer from cognitive impairment, and up to one-third of them progress to dementia. However, the underlying pathogenesis is complex and controversial. Recent evidence has found that cerebral small vessel disease (SVD) markers and the Alzheimer's disease (AD) neuroimaging marker medial temporal lobe atrophy (MTLA), alone or in combination, contribute to the pathogenesis of poststroke cognitive impairment (PSCI). In the present systematic review and meta-analysis, we synthesized proof for these neuroimaging risk factors among stroke patients. MATERIALS AND METHODS: PUBMED, MEDLINE, EMBASE and the Cochrane Library were searched for studies investigating imaging predictors of cognitive impairment or dementia following stroke. Meta-analysis was conducted to compute the odds ratios (ORs). RESULTS: Thirteen studies were enrolled in the present study, and only ten of them, comprising 2713 stroke patients, were eligible for inclusion in the meta-analysis. MTLA was significantly correlated with PSCI (OR = 1.97, 95% CI: 1.48-2.62, I2 = 0.0%). In addition, white matter hyperintensities (WMH), as a neuroimaging marker of SVD, were associated with PSCI (OR = 1.17, 95% CI: 1.12-1.22, I2 = 0.0%). However, the presence of lacunar infarcts and enlarged perivascular spaces (EPVS) were not associated with the risk of PSCI. CONCLUSIONS: The findings of the present study suggest that MTLA and WMH were associated with an increased risk of PSCI.