The Initial Exploration of Adamkiewicz Artery Computed Tomographic Angiography With Monochromatic Reconstruction of Gemstone Spectral Imaging.

OBJECTIVE: The study aimed to explore whether optimal monochromatic reconstruction can improve the depiction of the Adamkiewicz artery (AKA) on gemstone spectral computed tomographic angiography (GSCTA) compared with the polychromatic reconstruction protocol. METHODS: The prospective study was approved by the ethics committee, and written informed consent was obtained from each patient. The 58 consecutive patients suspected of aortic aneurysm or dissection underwent aortic GSCTA. All images were reconstructed with both polychromatic (group A) and optimal monochromatic (group B) protocol. The CT values of the descending aorta and muscle, background noise, and the contrast-to-noise ratio were measured and calculated. With the criterion standard display of AKA, characteristic hairpin curve sign, 2 blinded radiologists analyzed data independently with the paired samples t, χ, and Mann-Whitney U test. RESULTS: The CT value of the descending aorta and the contrast-to-noise ratio of group B were significantly superior to group A (t = 12.7, P < 0.01; t = 15.2, P < 0.01). The visual rate of AKA (94.8%) in group B was significantly higher (χ = 4.2, P = 0.04) than group A (82.8%). Using a 5-point scale to assess, the score of the visualization efficiency of group B (226) was significantly higher (Z = -2.4, P = 0.02) than group A (192). CONCLUSIONS: The optimal monochromatic reconstruction for GSCTA can improve the visualization efficiency and quality of the AKA compared with the polychromatic reconstruction protocol.

Discriminative analysis of early-stage Alzheimer's disease and normal aging with automatic segmentation technique in subcortical gray matter structures: a multicenter in vivo MRI volumetric and DTI study.

BACKGROUND: Previous studies have revealed that amyloid depositions exist in not only the hippocampus but in other subcortical gray matter structures as well. Diffusion-tensor imaging (DTI) parameters might be more sensitive measures of early degeneration in Alzheimer's disease (AD) than conventional magnetic resonance imaging (MRI) techniques. PURPOSE: To evaluate the significance of the volumes and the mean diffusivity (MD) values of subcortical gray matter structures in discrimination between early-stage AD and normal subjects using the Integrated Registration and Segmentation Tool in FMRIB's Software Library. MATERIAL AND METHODS: Fifty-three cases of early-stage AD and 30 normal aging volunteers from two hospitals were scanned with 3D-FSPGRIR and SSSE-EPI sequences using two similar 1.5T MR systems. The mean relative volumes and mean MD values of subcortical gray matter structures were compared between early-stage AD and control groups. Binary logistic regression analysis and receiver-operating characteristic (ROC) curves were applied to assess the diagnostic significance of every structure's relative volume, MD value, and combination of both. RESULTS: The relative volumes of the left hippocampus, right amygdala, bilateral thalamus, right caudate, left putamen, and bilateral pallidum were significantly lower in the early-stage AD group than in the control group (P < 0.05). The MD values of the bilateral hippocampus and pallidum, and of the right thalamus and caudate were significantly elevated in the early-stage AD group (P < 0.05). In binary logistic regression analysis, the relative volume of left hippocampus and age entered the final model of volumetric analysis. The MD values of bilateral hippocampi and pallidums entered the final model of MD analysis. The MD values of bilateral hippocampi and pallidums, and the relative volume of left pallidum, entered the final model of combination analysis. The accuracy of three models was 84.7%, 88.9%, and 93.1%, respectively. CONCLUSION: Pathological changes takes place in the hippocampus and other subcortical gray matter structures in early-stage AD. Diffusive imaging has great diagnostic significance in early-stage AD. The combination of both imaging modalities can lead to better discrimination between early-stage AD and normal aging.

[Multi-slice helical CT perfusion imaging in evaluating intracranial neoplasms and tumor-like lesions].

OBJECTIVE: To investigate the clinical value of CT perfusion in diagnosing and assessing intracranial neoplasms and tumor-like lesions. METHODS: 16-slice helical CT perfusion imaging was performed in 56 patients who were clinically suspected to have intracranial neoplasm or tumor-like lesion. With a GE-Light Speed 16-slice helical CT scanner, routine plain-CT scanning was performed to localize the central slice of the lesion. Perfusion imaging was then carried out using cine scan technique to maintain a slice thickness of 5-10 mm, a total dose of 50-70 ml of contrast-medium at an injection flow rate of 3-5 ml/s, a delay time of 7 s and a total scan time of 50 s. The images were processed using perfusion software in an ADW 4.0 workstation, meanwhile, time-density curves (TDC) of different kinds of lesions were also produced and analyzed. RESULTS: The pathological types in this series included: 29 gliomas (12 low-grade and 17 high-grade), 2 ependemomas, 2 hemangioblastomas, 1 medulloblastoma, 2 metastatic tumors, 1 lymphoma, 5 meningiomas, 2 schwannomas, 1 germinoma, 1 teratoma in the pineal region, 6 cavernous hemangiomas, 2 inflammatory granulomas, 1 tuberculoma, and 1 hyperplasia of the choroid plexus. TDC of high-grade glioma, low-grade glioma and meningioma was different from each other. The cerebral blood flow (CBF), cerebral blood volume (CBV), particularly, the permeability surface (PS) value of glioma was found to increase significantly with the escalation of tumor differentiation grade. In PS map, margin of the tumor could be clearly showed, which was very useful when hemorrhaging within the tumor occurred. CBF in meningioma was lower than that in high-grade glioma, but there was no statistical difference in CBV, MTT and PS between these two types of tumor. The features of intracranial cavernous hemangioma such as significant prolongation of MTT, different TDCs, and zero perfused areas were diverse on CTP image, which was helpful in differentiating it from the other lesions. The germinoma and teratoma had rather low CBF and CBV value, but a remarkably high PS value, furthermore, they showed a rapid escalated TDC with a slowly and continuously elevated platform. The perfusion features of schwannoma was concordant with its pathological findings. However, no visible specific feature of inflammatory lesion was found on CTP image in this series. CONCLUSION: Multi-slice helical CT perfusion imaging may be helpful in revealing histopathological features and hemodynamic changes as well as differential diagnosis of intracranial neoplasms and tumor-like lesions. When combined with other image and clinical information, CTP can play an important role in pre-operative diagnosis and treatment planning for intracranial neoplasms and tumor-like lesions.

[Prognostic value of MRI and 1H MRS in patients with temporal lobe epilepsy].

OBJECTIVE: To evaluate the prognostic value of hippocampal MRI scan, MRI volumetry and 1H MRS in patients with temporal lobe epilepsy (TLE). METHODS: 50 intractable TLE patients operated in Huashan hospital were studied. Before surgery, traditional MRI scans were used to exclude tumor and vascular malformation of the brain. All patients were examined by tilted coronal images which were perpendicular to the long axis of the hippocampus, using T1-weighted, T2-weighted and FLAIR sequence. MRI volumetric measurement of both hippocampal formation were performed. 38 patients also took 1H MRS scan. Unilateral anterior temporal lobectomy was performed in all patients and pathology showed different degrees of hippocampal sclerosis. The prognosis was categorized into three grades with grade I being assigned to the group of good outcome, and grade II and III being assigned to the bad outcome group. Correlative analysis between the results of several examinations and the prognosis were performed respectively. RESULTS: MRI-positive cases with hippocampal scans were about 84% of the 50 cases. Hippocampal atrophy, increase of signal intensity or the loss of internal morphological structure were detected. 98% of the MRI-positive patients had good outcome, and 38% of the MRI-negative patients had good outcome. The prognosis between MRI-positive group and MRI-negative group had significant difference (chi(2) = 23.00, P = 0.000). Among the right-side operated cases, the average hippocampal volume on the operated side of the bad outcome group was larger than that of the good outcome group. While among the left-side operated cases, the hippocampal volume on the non-operated side of the bad outcome group was smaller than that of the good outcome group. Significant differences were found in statistics respectively. In both groups, prognosis was found to be statistically related to the DHF value (difference of bilateral hippocampal volume). The DHF value of the good outcome group was larger than that of the bad outcome group. 38 patients took 1H MRS examination. The average NAA/(Cr + Cho) ratio on the operated side of the patients in the bad outcome group was greater than that of the good outcome group. The average NAA/(Cr + Cho) ratio on the contralateral side of the patients in the bad outcome group was lower than that of the good outcome group. But no significant differences were found in statistics respectively. 90% cases of MRS unilateral abnormalities had good outcome, while 77% cases of MRS bilateral abnormalities had good outcome. But no statistically significant difference was found among different groups (chi(2) = 0.493, P = 0.781). CONCLUSION: Hippocampal MRI scan, MRI volumetry and 1H MRS may be used as prognostic tools in TLE patients before surgery. The combination of several noninvasive methods before surgery can help choose suitable patients for surgery, and, as a result, improve surgical outcome.