The correlation of hippocampal T2-mapping with neuropsychology test in patients with Alzheimer's disease.

OBJECTIVES: 1) To deduce T2, the inverse of the transverse relaxation rate (R2), in the hippocampus of healthy adults; 2) to investigate the brain iron deposition in Alzheimer's disease (AD) patients and age-matched healthy controls using T2-values. METHODS: T2-weighted data from the bilateral-hippocampi of ten AD patients and sixty healthy controls were collected at six echo time points using multi-slice multi-echo turbo spin echo (MSME-TSE) imaging on a 3.0 T MR-scanner, followed by the neuropsychological testing. The correlations between T2-values and Mini-Mental State Examination (MMSE) scores were investigated on group-wise basis (covariates in the group-wise analyses: gender, age, side and healthy/AD). RESULTS: There were no significant differences in hippocampal T2-values on intra-gender and inter-gender basis (P > 0.05). Hippocampal T2-values of both sides were similar (right: 85.2±2.4 milliseconds; left: 85.3±2.5 milliseconds). The bilateral hippocampal T2 values correlated moderately with age (right: r = -0.59; left: -0.58; P < 0.001). The AD-group had significantly lower T2-values in the hippocampus when compared to normal controls (P < 0.001) and such low T2-values had a strong positive correlation with the MMSE score (R (2) = 0.97; P < 0.05). CONCLUSION: Patients with AD showed significantly lower T2 values, which can be attributed to the increased iron depositions in the hippocampus. A positive correlation between T2-values and cognition scores suggests that quantitative T2 can be used in the early diagnosis of AD and in the monitoring of the treatment response.

Comparison of the accuracy of subtraction CT angiography performed on 320-detector row volume CT with conventional CT angiography for diagnosis of intracranial aneurysms.

OBJECTIVE: The accuracy of diagnosis of intracranial aneurysms by subtraction computed tomography angiography (CTA) was compared with conventional non-subtracted CTA and with digital subtraction angiography (DSA). METHODS: 56 patients with spontaneous subarachnoid hemorrhage (SAH) and suspected intracranial aneurysms were evaluated from September 2009 to January 2010. All underwent 320-detector row volume CT-CTA examinations. Non-contrast CT of each patient's head with the same scan range was performed before the routine CTA scan as the mask image for subtraction. The subtraction CTA volume data was obtained by subtracting the mask image volume data from the conventional non-subtracted CTA volume data. Subtraction and conventional CTA volume data were transmitted to a VOXAR workstation and two physicians with experience in diagnostic imaging of the nervous system independently carried out image post-processing and judged the results. Neurosurgeons performed endovascular treatment or surgical clipping based on information available through the CTA alone. RESULTS: In 42 patients, 51 aneurysms were detected by DSA. On a per-aneurysm basis, the diagnostic sensitivity of subtraction CTA was 98.9% for physician 1 and 100% for physician 2. The sensitivity of conventional CTA was 93.7% for physician 1 and 92.6% for physician 2. There was excellent inter-observer agreement (κ=0.84, 95% confidence interval 0.82-0.85). The overall sensitivity, specificity, positive predictive and negative predictive values of subtraction CTA were all 100%. The overall sensitivity, specificity, positive predictive and negative predictive values of non-subtracted CTA were 94%, 100%, 100% and 76%, respectively. Therapeutic decisions could be made for all 42 patients based on subtraction CTA images, whereas conventional non-subtracted CTA provided sufficient information to make therapeutic decisions for only 35 patients. CONCLUSION: Conventional CTA has lower sensitivity for the detection of very small aneurysms and aneurysms adjacent to the skull when compared to subtraction CTA. Subtraction CTA performed on a 320-detector row volume CT is an accurate diagnostic tool that provides data equivalent to that obtained with three-dimensional-DSA for the detection of intracranial aneurysms.

Initial experience on the application of 320-row CT angiography with low-dose prospective ECG-triggered in children with congenital heart disease.

To investigate the clinical significance of the application of 320-row CT angiography with low-dose prospective ECG-triggered target scanning in children with complex congenital heart disease (CHD), and to compare with the results from transthoracic echocardiography (TTE). 22 patients (male 12 cases, female 10 cases, average age: 18 months, range: 14 days-9 years, average weight: 13 kg) received an examination through 320-row CT angiography with low-dose prospective ECG-triggered volume target scan mode and transthoracic echocardiography. The center of phase window for data collection in this study was set to 40% of the R-R interval. Of these, 18 patients received surgery and 4 patients received conventional cardiac angiography (CCA). The diagnostic accuracy of 320-row CTA was calculated according to the examination results from surgical and/or cardiac angiography. The overall quality score for CTA images was divided into five levels. The results were compared with the research data of radiation doses obtained from patients with congenital heart disease who had received CT angiography. Complex congenital heart disease was confirmed by surgical or CCA in each of 22 patients, with 42 cases of large vascular malformations outside the heart cavity, and 26 of intracardiac malformations. The diagnostic accuracy of 320-row CT angiography and transthoracic echocardiography for large vascular malformation outside the heart cavity was 95.2 and 80.9%, respectively; for intracardiac malformation the accuracy was 88.5 and 100.0%, respectively. There was significant difference between 320-row CT and transthoracic echocardiography in the diagnosis of large vascular malformation outside the heart cavity (P < 0.05) with better results in 320-row CT, and no significant difference was found in the diagnosis of intracardiac malformation (P > 0.05). The average subjective image quality score was 4.4 ± 0.7 points. The average effective dose was 0.42 ± 0.08 mSv. 320-row CT enables direct visualization of the vascular configuration and shape of the aorta, pulmonary artery, and other large vessels to diagnose extracardiac vascular malformations. Combined with transthoracic echocardiography, 320-row CT is a promising technology that may be able to replace catheter based angiography to evaluate congenital cardiovascular malformations.