Assessment of optic nerve and optic tract alterations in patients with orbital space-occupying lesions using probabilistic diffusion tractography.

AIM: To investigate the diffusion changes in both the optic nerve and optic tract in orbital space-occupying lesion patients with decreased visual acuity, and its clinical significance using probabilistic diffusion tractography (PDT). METHODS: Twenty patients with orbital space-occupying lesions and 25 age- and gender-matched healthy persons were included. All patients and controls underwent routine orbital magnetic resonance imaging and diffusion tensor imaging (DTI), using a 3.0T magnetic resonance scanner (Trio Tim Siemens). After the image data were preprocessed, each DTI parameters of the optic nerve and optic tract was obtained by PDT, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). The asymmetry index (AI) of each parameter was calculated. Compared the parameters of the affected side optic nerve and ipsilateral optic tract with the contralateral side by paired sample t-test; compared AI of parameters of optic nerve and optic tract between the patient group and the control group by independent sample t-test. Patients were divided into three subgroups according to the low vision grade standard of WHO, compared the FA and AI of FA between the three subgroups by single factor variance analysis. RESULTS: The affected side optic nerve presented significantly decreased FA, increased MD, AD, and RD values compared to the unaffected side (P<0.05). The AI of FA, MD, AD, and RD of optic nerve in the patients was significantly higher than that of the controls (P<0.05). The comparison results of the optic tract showed that there was no significant difference between the patient group and control group in terms of the bilateral optic tracts in patients (P>0.05). The AIs of the FA value of the optic nerve in the eyesight <0.1 subgroup was significantly higher than that in the other groups (P<0.05). CONCLUSION: FA, MD, AD, and RD of the affected side optic nerve of the orbital space-occupying lesions have significantly changed, the FA value is the most sensitive. The PDT could be a useful tool to provide valid quantitative markers of optic nerve injuries and evaluate the severity of orbital diseases, which other examinations cannot be acquired.

Assessment of the right and left ventricular function in patients with cor pulmonale using high-definition CT.

BACKGROUND: Cor pulmonale is often associated with changes of structure and function of the right ventricle (RV) and thus further affects functional changes of the left heart. Our study aimed to assess the left ventricular (LV) and RV function in patients with cor pulmonale using high-definition CT (HDCT). METHODS: We prospectively studied 18 cor pulmonale patients determined by the pulmonary function test, clinical examination, chest radiograph, electrocardiogram, and echocardiogram. The subject group was compared to a control group consisting of 18 subjects. The RV and LV functions and RV myocardial mass (MM) were obtained by HDCT in the two groups. The results were compared between the two groups using the independent sample t test. Echocardiographic examination for cardiac function analysis was performed on the same day. RESULTS: The RV end-diastolic volume (EDV), RV end-systolic volume (ESV) and RV myocardial mass were significantly larger in the 18 cor pulmonale patients than in the control group (P < 0.05). The right ventricular ejection fraction (RVEF) was significantly lower in the 18 cor pulmonale patients than in controls (P < 0.01). The left ventricular EDV (LVEDV) and LVEF were significantly lower in cor pulmonale patients than in controls (P < 0.01). There were strong correlations between MDCT and echocardiography, rRVEF = 0.839 and rLVEF = 0.916, respectively. CONCLUSIONS: HDCT can accurately quantify RV and LV function. The right ventricular function is impaired in patients with cor pulmonale, while at the same time the left ventricular function is also impaired.

[Assessment of right ventricular cardiac function using 64-detector CT: comparison with MRI].

OBJECTIVE: To investigate the value of 64-detector spiral computed tomography versus MRI in the assessment of right ventricular function. METHODS: Thirty healthy volunteers (15 males, 15 females, 48 +/- 24 years) underwent 64-detector spiral computed tomography CT and breath-hold MRI. With semiautomatic contour detection software, the parameters of end-diastolic volume, end-systolic volume, stroke volume and ejection fraction were determined from short-axis CT reformations (MPR) created at every 5% of RR-interval. The results from CT were compared with those from MRI using Pearson correlation test and Bland-Altman plot. RESULTS: The CT values of mean end-diastolic volume (146 +/- 27) ml, end-systolic volume (70 +/- 20) ml, stroke volume (75 +/- 12) ml and ejection fraction (52% +/- 5%) correlated well with those by MRI [146 +/- 25 ml (r = 0.959), 66 +/- 17 ml (r = 0.914), 80 +/- 15 ml (r = 0.706), 55% +/- 7% (r = 0.612)]. A strong correlation between MSCT and MRI was also found in the Bland-Altman plot. CONCLUSION: 64-detector spiral CT can accurately assess the right ventricular function. It is a valuable method for evaluating cardiac function.

Diffusion tensor tractography in patients with cerebral tumors: a helpful technique for neurosurgical planning and postoperative assessment.

OBJECTIVE: To demonstrate the role of diffusion tensor tractography (DTT) in preoperative mapping of eloquent tracts in relation to cerebral tumors and to determine whether it is helpful for neurosurgical planning and postoperative assessment. METHODS AND MATERIALS: Sixteen patients with brain tumors underwent diffusion tensor imaging (DTI). The pyramidal tract, corpus callosum and optic radiation were reconstructed and the exact location of a lesion with respect to these tracts was observed to design a reasonable surgical plan for preserving vital tracts while maximizing tumor resection. After surgery, DTI was performed again and these tracts were evaluated to investigate the surgical outcomes. Twenty-four patients with suspicion of pyramidal tract involvement were also evaluated as a control group. RESULTS: The relationship between tracts and tumors was classified as three types: type I is simple displacement, type II is displacement with disruption and type III is simple disruption. Twelve cases involved in pyramidal tract (DTT group), one was type I with reduction of displacement after surgery, nine were type II with reduction of displacement and other two were type III without any improvement. The extent of tumor resection (p = 0.045) and postoperative improvement of locomotive function (p = 0.015) of DTT group were significantly higher than those of control group. Corpus callosum was involved in seven cases, three were type II with reduction of displacement and four were type III without any improvement. Optic radiation was involved in three cases, all were type I with reduction of displacement. CONCLUSION: DTT allowed for visualization of the exact location of tumors relevant to eloquent tracts and was found to be beneficial in the neurosurgical planning and postoperative assessment.