ABSTRACT
Background: This study set out to evaluate the utility of cerebrovascular virtual non-contrast [VNC] scans. Materials and Methods: Conventional non-contrast [CNC] and dual-energy computed tomography angiography [DE-CTA] head scans were conducted on 100 subjects, of which 46 were normal, 15 had parenchymal hematomas of the brain, 13 had ischemic infarction, 22 had tumors, and 4 had calcified lesions. VNC images were extracted from the DE-CTA head scans by post-processing. The true [or conventional] and VNC images were compared in terms of the mean CT attenuation value and signal-to-noise ratio [SNR] of the cerebral parenchyma, the image quality, the lesion detection sensitivity, and the radiation exposure level. Results: The image qualities of the CNC and VNC scans were [4.95 +/- 0.22] points and [3.94 +/- 0.24] points [t = 31.18, P < 0.05], the mean CT values for the CNC and VNC images were [34.6 +/- 2.44] and [28.6 +/- 5.40] HU [t = 10.126, P < 0.05], the SNRs were [9.45 +/- 1.26] and [6.87 +/- 1.77], and the HU for white matter was [t = 11.859, P<0.05], respectively. The effective radiation doses from the DE-CTA head scans and the conventional non-contrast scans were [8.55 +/- 0.57] mSv and [9.41 +/- 1.00] mSv, respectively. No significant difference in the lesion detection sensitivities was observed between the CNC and VNC scans, except for tiny calcified lesions, which could not be identified by a VNC scan. Conclusion: VNC and contrast-enhanced images could be obtained from DE-CTA head scans and could aid in the diagnosis of cerebral lesions. The radiation dose from the VNC scan was less than that from the CNC scan
ABSTRACT
An in-situ experiment was conducted to investigate the effect of tropical storm on the white spot syndrome virus [WSSV] loads in Litopenaeus vannamei rearing ponds. White spot syndrome virus loads, heterotrophic bacteria, Vibrio and water quality [including temperature, dissolved oxygen [DO], salinity, pH, NH4-N, and NO2-N] were continually monitored through one tropical storm. The WSSV loads decreased when tropical storm made landfall, and substantially increased when typhoon passed. The variation of WSSV loads was correlated with DO, temperature, heterotrophic bacteria count, and ammonia-N concentrations. These results suggested that maintaining high level DO and promoting heterotrophic bacteria growth in the shrimp ponds might prevent the diseases' outbreak after the landfall of tropical storm
ABSTRACT
This study was performed to better understandpostoperative contralateral subdural effusion, an uncommon but serious complication secondary to decompressive craniectomy in patients with head trauma. Data from medical records of 169 patients who underwent decompressive craniectomy after head trauma between 2003 and 2006 were collected. The data included demographics, clinical presentations, treatment and outcome. Of the 169 patients, 11 [6.5%] had contralateral subdural effusion. On the average, this complication was found 14 days after decompressive craniectomy. Of the 11 patients, conservative treatment was effective in 7 with a gradual resolution which lasted 52.7 days on average. The effusion in the remaining 4 patients led to progressive deterioration of clinical presentation, and surgical intervention was necessary: subduroperitoneal shunting in 3 cases and burr hole drainage in the remaining 1 case. Our findings confirmed that postoperative contralateral subdural effusion was not an uncommon complication secondary to decompressive craniectomy. Most contralateral subdural effusions resolved spontaneously after conservative management, but surgical management may be necessary if the patients develop deteriorating clinical manifestations or the subdural effusion has an apparent mass effect