High-resolution MRI assessment of optic nerve sheath diameter in adults: optic nerve sheath variation and a new diagnostic tool for intracranial hypertension.

BACKGROUND: Assessment of optic nerve sheath diameter (ONSD) is a non-invasive measure of intracranial pressure (ICP). However, it is not clear whether healthy individuals exhibit ONSD variation or whether factors other than ICP affect the ONSD. PURPOSE: To investigate whether ONSD was correlated with age, sex, height, weight, eyeball transverse diameter (ETD), or body mass index (BMI), and to develop a new diagnostic model to increase the diagnostic accuracy of intracranial hypertension (IH). MATERIAL AND METHODS: A total of 145 relatively healthy adults and 40 patients with acute IH who underwent high-resolution magnetic resonance imaging (MRI) were enrolled in this study. Linear regression analyses were used to determine the relationship between ONSD and these variables. If correlations were identified, an index ONSDΔ removing variables effects was calculated. ROC analysis was used to assess the IH predictive value of ONSDΔ in terms of sensitivity and specificity. RESULTS: In relatively healthy adults, there was a correlation between ONSD and BMI (P = 0.002), which can be presented as an index ONSDΔ. The ONSDΔ model better predicted IH than the ONSD model (P = 0.035), with a sensitivity of 70.00%, a specificity of 71.72%, and an AUC of 0.755. CONCLUSION: A correlation between ONSD and body mass index (BMI) was found using high-resolution MRI. This result indicates that the effects of BMI should be considered along with the ONSD during ICP monitoring. Meanwhile, the index ONSDΔ was better than the ONSD in predicting IH and could be used to obtain a more precise estimation of ICP.

Diagnostic value of mitral regurgitant jet volume in the assessment of mitral regurgitation severity by general imaging three-dimensional quantification.

Accurate quantification of mitral regurgitation (MR) severity is critical for appropriate clinical decision making regarding surgical intervention. General imaging three-dimensional quantification (GI3DQ) method allows for direct measurement of mitral regurgitant jet volume (MRJvol) with the help of three-dimensional (3D) color flow Doppler imaging. The aim of this study was to evaluate diagnostic value of MRJvol by GI3DQ for MR grading severity, using the guideline recommended integrated approach as a reference. The study included ninety-seven patients with varying degree of MR, and all MR cases were divided into central MR group (n = 44) and eccentric MR group (n = 53). The MRJvol was measured by GI3DQ. The severity of MR was graded on the basis of recommended integrated approach as mild, moderate, or severe. As assessed by receiver operating characteristic analysis, MRJvol by GI3DQ at a cutoff value of 43.4 ml yielded 76.9% of sensitivity and 86.9% of specificity to differentiate moderate from severe MR in all cases, a cutoff value of 47.5 ml yielded 98.9% of sensitivity and 94.4% of specificity to differentiate moderate from severe MR in central MR, and a cutoff value of 40.7 ml yielded 80.0% of sensitivity and 78.6% of specificity to differentiate moderate from severe MR in eccentric MR. MRJvol measured by GI3DQ could assess MR severity, especially in central MR group, which has higher sensitivity and specificity to differentiate moderate from severe MR.

The impact of different geometric assumption of mitral annulus on the assessment of mitral regurgitation volume by Doppler method.

BACKGROUND: Mitral regurgitation volume (MRvol) by quantitative pulsed Doppler (QPD) method previously recommended suffers from geometric assumption error because of circular geometric assumption of mitral annulus (MA). Therefore, the aim of this study was to evaluate the impact of different geometric assumption of MA on the assessment of MRvol by two-dimensional transthoracic echocardiographic QPD method. METHODS: This study included 88 patients with varying degrees of mitral regurgitation (MR). The MRvol was evaluated by QPD method using circular or ellipse geometric assumption of MA. MRvol derived from effective regurgitant orifice area by real time three-dimensional echocardiography (RT3DE) multiplied by MR velocity-time integral was used as reference method. RESULTS: Assumption of a circular geometry of MA, QPD-MAA4C and QPD-MAPLAX overestimated the MRvol by a mean difference of 10.4 ml (P < 0.0001) and 22.5 ml (P < 0.0001) compared with RT3DE. Assumption of an ellipse geometry of MA, there was no significant difference of MRvol (mean difference = 1.7 ml, P = 0.0844) between the QPD-MAA4C + A2C and the RT3DE. CONCLUSIONS: Assuming that the MA was circular geometry previously recommended, the MRvol by QPD-MAA4C was overestimated compared with the reference method. However, assuming that the MA was ellipse geometry, the MRvol by the QPD-MAA4C + A2C has no significant difference with the reference method.