Diffusion tensor imaging analysis in scrub typhus meningoencephalitis to determine the alteration of microstructural subcortical white-matter integrity

Predicting the efficacy of high-intensity focused ultrasound (HIFU) ablation for uterine leiomyomas based on DTI indicators and imaging features

PURPOSE

To predict the efficacy of high-intensity focused ultrasound (HIFU) ablation for uterine leiomyomas based on diffusion tensor imaging (DTI) indicators and imaging features.

METHODS

Sixty-two patients with 85 uterine leiomyomas were consecutively enrolled in this retrospective study and underwent DTI scanning before HIFU treatment. Based on whether the non-perfused volume ratio (NPVR) was greater than 70%, all patients were assigned to sufficient ablation (NPVR ≥ 70%) or insufficient ablation (NPVR < 70%) groups. The selected DTI indicators and imaging features were incorporated to construct a combined model. The predictive performance of DTI indicators and the combined model were assessed using receiver operating characteristic (ROC) curves.

RESULTS

There were 42 leiomyomas in the sufficient ablation group (NPVR ≥ 70%) and 43 leiomyomas in the insufficient ablation group (NPVR < 70%). The fractional anisotropy (FA) and relative anisotropy (RA) values were higher in the sufficient ablation group than in the insufficient ablation group (p < 0.05). Conversely, the volume ratio (VR) and mean diffusivity (MD) values were lower in the sufficient ablation group than those in the insufficient ablation group (p < 0.05). Notably, the combined model composed of the RA and enhancement degree values had high predictive efficiency, with an AUC of 0.915. The combined model demonstrated higher predictive performance than FA and MD alone (p = 0.032 and p < 0.001, respectively) but showed no significant improvement compared with RA and VR (p > 0.05).

CONCLUSION

DTI indicators, especially the combined model incorporating DTI indicators and imaging features, can be a promising imaging tool to assist clinicians in predicting HIFU efficacy for uterine leiomyomas.

Scrub Typhus Meningoencephalitis: An Overlooked Entity

Scrub typhus is common in rural parts of Nepal, but its diagnosis remains difficult due to a lack of clinical suspicion and poor diagnostic resources. The absence of common clinical features further complicates this problem. Acute kidney injury (AKI), myocarditis, rhabdomyolysis, hepatitis, acute respiratory distress syndrome, and meningoencephalitis are complications of the disease associated with high mortality. Overlap findings can be noted in scrub typhus meningoencephalitis and other tropical infections. This makes diagnosing the disease more challenging, especially in areas where the burden of infectious diseases is high. We report three cases of scrub typhus meningoencephalitis. All three patients were treated successfully with doxycycline. Because patients with scrub typhus have an excellent response to treatment, delay in treatment and rate of complications can be prevented with high clinical suspicion of the condition.

Diffusion tensor imaging analysis of rheumatoid arthritis patients with neuropsychiatric features to determine the alteration of white matter integrity due to vascular events

INTRODUCTION

The pathophysiology of neuropsychiatric manifestations in rheumatoid arthritis is not well known. The magnetic resonance imaging of the brain in rheumatoid arthritis demonstrates non-specific findings, and in the majority of cases, magnetic resonance imaging fails to detect an abnormality, even in rheumatoid arthritis patients with neuropsychiatric manifestations. Therefore, we aimed to assess microstructural integrity changes of white matter in patients with rheumatoid arthritis by using different diffusion tensor imaging parameters.

METHODS

Eighteen rheumatoid arthritis patients (10 with neuropsychiatric symptoms and 8 without any neuropsychiatric symptoms) and 14 controls were included. The volume of the T2 hyperintense lesions was assessed. Different diffusion tensor imaging parameters such as fractional anisotropy, apparent diffusion coefficient, trace, axial diffusivity, and radial diffusivity were obtained from six different regions of white matter. Inter group significant difference was determined by one-way analysis of variance followed by Tukey's post hoc test. The accuracy of diffusion tensor imaging matrices was evaluated from the receiver operating characteristic curve.

RESULTS

No significant difference in lesions' volume was detected between rheumatoid arthritis patients with or without neuropsychiatric symptoms. There was an increased apparent diffusion coefficient and radial diffusivity (p < 0.05) as well as decreased fractional anisotropy and axial diffusivity (p < 0.5) in rheumatoid arthritis patients with neuropsychiatric symptoms compared to controls. Moreover, the apparent diffusion coefficient (p < .05) was increased in both positive and negative MRI of patients with neuropsychiatric features compared to the control group. The sensitivity and specificity of the apparent diffusion coefficient parameters was 73% and 72%, respectively.

CONCLUSIONS

The various anisotropic metrics were altered in rheumatoid arthritis patients with neuropsychiatric symptoms by using diffusion tensor imaging analysis, representing that central nervous system vasculitis leads to tissue hypoxia resulting in vasogenic edema. This may lead to axonal and myelin degeneration of white matter fibers and neuronal cell disruption. Key Points • Our study confirms that neurovascular events are not uncommon in RA patients with NP features. Diffusion tensor imaging (DTI) is superior to conventional MRI scan for RA patients with NP features because it distinguishes between gray and white matter structures. • RA patients with NP features are more likely to have microstructural changes detected by DTI than by DWI, and it can provide comprehensive anatomical layouts describing regional disparities in neurodegeneration. • DTI's quantitative association of NP symptoms in a large patient cohort is an important study scope.