Introduction Of Computed Tomography Scanning Research Articles

Evaluation and comparison of performance of low-dose 128-slice CT scanner with different mAs values: A phantom study.

OBJECTIVE:Radiation dose in computed tomography (CT) has been the concern of physicists ever since the introduction of CT scan. The objective of this study was to evaluate the performance of low-dose 128-slice CT scanner with different mAs values.MATERIALS AND METHODS:Quantitative study was carried out at different values of mAs. Philips brilliance CT phantom with Philips ingenuity 128-slice low-dose CT scanner was chosen for this study. CT number linearity, CT number accuracy, slice thickness accuracy, high-contrast resolution, and low-contrast resolution were calculated and estimated computed tomography dose index volume (CTDIvol) for all the mAs values were recorded. Noise was calculated for all mAs values for comparison.RESULTS:Data analysis shows that image quality was acceptable for all protocols. High-contrast resolution for all protocols was 20 line pairs per centimeter. Low-contrast resolution for 50 mAs images was 4 mm and 3 mm for other mAs protocols. Images acquired using 100 mAs revealed ring artifacts. CTDIvol using 50 mAs was 33% of the CTDIvol using 150 mAs. The dose–length product at 100 mAs was reduced to 66% of the dose–length product at 150 mAs, and the same at 50 mAs was reduced to 33%.CONCLUSION:It is evident here that mAs has direct impact on the radiation dose to patient. With iDose4, mAs can be reduced to 50 mAs in multislice low-dose CT scan to reduce the radiation dose with minimal effect on image quality for slice thickness 4 mm. However, noise would dominate at tube current lower than 50 mAs for 120 kVp.

Pulmonary metastasectomy of colorectal cancer origin: Evaluating process and outcomes.

This study was undertaken to evaluate the effect of change in policy of computed tomography (CT) scan of the thorax in staging and follow-up of colorectal cancer (CRC). Another objective was to review the outcomes following pulmonary metastasectomies (Pmets) and to determine the prognostic factors affecting outcomes. This is a retrospective analysis from a prospective cohort database of patients, who underwent Pmet for CRC origin from August 2004 to February 2016. The outcome measures were number of Pmets per year, overall survival (OS), disease-free survival (DFS), and prognostic factors affecting survival. Of 71 patients, 38% (n = 27) underwent Pmet before 2013 and 62% ( n = 44) had surgery after 2013. The 2-year DFS after Pmet was 49.3% and estimated 5-year OS was 51.4% at a median follow-up of 28 months. There was a significant increase in number of Pmets/year ( P = 0.0015), increased detection of synchronous pulmonary metastasis (PM) ( P = 0.005), increased diagnosis of extra-pulmonary metastases (EPM) ( P = 0.005), and improved OS ( P = 0.026) after introduction of CT scan as staging tool. Site of primary tumor (colon) ( P = 0.045), primary nodal stage ( P = 0.009), and the presence of EPM ( P = 0.01) were independent important prognostic factors affecting survival. The CT scan of thorax as a baseline tool for staging and follow-up in CRC increases referral for pulmonary metastasectomy. Surgery achieves excellent prognosis and long-term survival outcomes in CRC with isolated PM and carefully selected patients with solitary liver metastasis.

The increasing incidence of malignant gliomas and primary central nervous system lymphoma in the elderly

Studies indicate that the incidence of primary malignant brain tumors in the elderly is increasing, but this may reflect increased case ascertainment due to the introduction of computed tomography (CT) scanning. In addition, tumor histology was not available in these studies. This study was conducted to determine whether the incidence of primary malignant brain tumors in the elderly in Florida is increasing and to verify the histology of these increases. Using the number of primary malignant brain tumors reported to the Florida Cancer Data System (FCDS) when CT scanning was available, incidence rates per 100,000 people were calculated. Incidence density ratios (IDRs) were calculated for 1986-1989 relative to 1981-1984. Tumor incidence at ages 20-64 years increased from 5.7 in 1981-1984 to 5.9 in 1986-1989, with an IDR of 1.05 (not significant). The incidence in those aged 65 years or older rose from 14.8 to 18.3, with an IDR of 1.23 (P < 0.001). The increase was 15% in those aged 65-69, 16% in those 70-74 years, 30% in those 75-79 years, 36% in those 80-84 years, and 254% in those 85 years or older. Indicence density ratios in those aged 65 years or older were 0.92 (not significant) for astrocytoma, 2.7 (p < 0.001) for anaplastic astrocytoma, 1.32 (p < 0.001) for glioblastoma and 3.56 (p < 0.001) for lymphoma. In those aged 65+ the incidence of all cancers rose 7.6% (not significant), and the incidence of pancreatic cancer (another neoplasm that requires CT scanning for diagnosis) rose 0.34% (not significant). The incidence of primary brain tumors in elderly Floridians has increased. This increase is independent of increased case ascertainment associated with the introduction of CT scanning and independent of a general increase of all cancers. The rise in brain tumor incidence is observed in anaplastic astrocytoma, glioblastoma, and lymphoma but not astrocytoma. This study confirms the increase is histologically specific and not due to increased case ascertainment. Further investigation into the etiology of this increase is warranted.

Surgical Indication of Hypertensive Cerebellar Hematoma

Until now, investigations have indicated that small cerebellar hematomas should be treated conservatively. But the treatment for medium-sized hematoma is still controversial, and the outcome of surgical treatment of large hematomas is not always good. The authors therefore studied the clinical results of hypertensive cerebellar hematomas, especially for medium-sized and large hematomas, and the surgical indication based on preoperative computed tomography (CT) findings and clinical findings was considered. Thirty-seven patients with hypertensive cerebellar hematomas were treated after the introduction of CT scan. In nineteen patients, hematoma evacuations were carried out under suboccipital craniectomy with or without ventricular drainage. In three patients only ventricular drainage or ventriculo-peritoneal shunt was carried out. The other eighteen patients were treated conservatively. In studying the series, the size of hematoma was classified as follows: the maximum diameter of a small hematoma was 2 cm or less, and that of a large hematoma was 3.5 cm or more. The clinical results were evaluated by the activities of daily living on discharge. From the results, the surgical indication of hypertensive cerebellar hematoma was considered as follows: 1) In patients with medium-sized hematoma (more than 2 cm, less than 3.5 cm), alert or somnolent patients should be treated conservatively. Hematoma evacuation is indicated in stuporous patients. 2) In patients with large hematoma (3.5 cm or more), hematoma should be evacuated within 24 hours after onset. Comatose patients, however, cannot achieve an independent daily life.

Clinical Study of Traumatic Intracerebellar Hemorrhage

Eleven cases of traumatic intracerebellar hemorrhage caused by severe head injury were presented and examined for their neurological signs, associated computed tomography (CT) findings and their outcome. These cases were divided into two types. The first is an acute type, which showed intracerebellar hemorrhage on the initial CT, and the second is a delayed type, which showed a hemorrhage on a subsequent CT without any findings in the posterior fossa in the initial CT scanning. The state of consciousness on admission of these patients was 8 or less by the Glasgow Coma Scale except for one case. Signs of brain stem injury were frequently seen on admission, such as absence of oculocephalic reflex, respiratory disturbance, and conjugate deviation of the eyes. Cerebellar signs were not usually observed. Nine out of 11 patients died and the Glasgow Outcome Scales of the two surviving cases were severe disability and persistent vegetative state. Associated CT findings of supratentorial region were observed in all cases of the acute type and three cases (75%) of the delayed type. There was not much difference in the neurological signs and the associated CT findings between the acute type and the delayed type. These results suggest that a strong impact acted on a supratentorial region as well as on the posterior fossa. With the introduction of CT scan, it has become much easier to diagnose this pathology. These cases suggest that a prompt evacuation of the hematoma or decompression of the posterior fossa should be attempted to yield satisfactory clinical results.

Computed Tomography of the Thorax and Abdomen; A Preliminary Report

The utility of computed tomography (CT) in the study of the anatomy, physiology, and pathology of the human body has been the subject of considerable interest since the introduction of CT scanning. The advent of a new prototype scanning device has made it possible to examine a variety of abnormalities in the abdomen and thorax in a manner not previously possible. This development permits a remarkable insight into the study of human disease in vivo.