Computed tomography (CT) is an important investigative tool. Its use has increases in frequency as it looks into the anatomy of the body without any actual invasion. In this study or objective was to evaluate the clinical yields of CT brain in geriatric patients. A nested cohort study was conducted on 117 patients and indications of the scan were noted. It was found that only 25% of the ordered scans visualized any anomalies. And only 34% of the scans with abnormal findings lead to treatment changes.
Only the lesions of focal neurological deficit were significantly associated with treatment changes after CT scans. The study showed that overall clinical yield of the CT scans is low and can be improved by ordering only targeted scans. Review Computed Tomography (CT) has become a frequent investigative tool due to its ability to visualize the anatomy of the body without its invasion. It is being used for purposes which have low diagnostic yield, including altered mental status, cerebrovascular accidents and altered mental status.
In elderly patients, the use of sedatives during procedures can lead to risk of aspiration and falls. The purpose of this study was to investigate the frequency of CT scan use and indications for its use. The aim further was to investigate the frequency of detection of abnormal intracranial findings and its influence in altering the course of management in the patient. A nested cohort study was conducted on a previous prospective study of geriatric patients. Patients who had undergone a CT scan upon admission or during hospitalization were admitted to the study.
Indications for the scans were recorded and data extracted from the CT scans of positive findings. Records were also reviewed to note if there were any alterations to the treatments after administration of the CT scans. The positive predictive factors that are associated with positive findings on the CT scan, according to the study included males, aged 80 years, non white race. Indicators also included patients who were delirious or had a history of delirium, alcohol and cigarette use, fever above 101. 5F, had a fall or syncope.
Of the 919 patients in the previous study, 117 patients had had a CT scan upon admission or during the course of hospital stay. Of the 24% of scans demonstrated abnormalities. Most frequently the study showed that scans were ordered to rule out intracranial hemorrhage, then cerebrovascular accident etc. According to the study, only 10 % of scans actually lead to findings of acute infarcts and intracranial hemorrhage. 34% of the scans detected old infarcts which were incidental findings. It was found that of the 28 scans of the total 117 scans led to true positive findings.
Only 10 scans, 35. 7% of true positive scans and 8. 5% of total scans led to any changes in the treatment plans, these included patients in whom, cute infarcts or hemorrhages had been detected. Of the 11% scans ordered for the indication of altered mental status, it was found that no scans led to alteration of treatment. No major complication related to dye use or sedative medication was recorded. The only significant predictor that led to significant clinical yield was the indication for “new neurological deficit”.
The study revealed that if the scans were reserved for people with focal neurological deficit, the clinical yields would improve. Discussion This study, a prospective cohort of old general medical patients, has led us to highlight the problem. Too often, CT scans are being utilized for purposes which are of little benefit to the patient and led to no management changes. Risk of over use of this imaging tool starts use of sedation. In the elderly patients, this can lead to risk of fall, injury or aspiration. This radiographic tool often utilizes contrast medium to visualize the sections. The contrast dyes have a nephrotoxic affect.
In elderly patients, who are already diabetic or have decreased renal function, this can lead to renal shutdown. Lastly the CT scans are radiological scans which emit radiation produce a result. These high dose radiations are many folds higher than the quantity emitted by plain x-rays. Frequent CT scans can also led radiation related problems. All the risks involved with the use of the scans only highlight the care which must be taken while selecting elderly patients who are to undergo CT scans. It also highlights the need for evaluating the risk benefit ratio before the CT scan is ordered.
The study revealed that only 6% of the requested scans lead to actual positive findings and even a lesser percentage had alterations in their management plans after the CT results were available. The study impresses upon the need to develop a guidelines for requesting CT scans, to improve its clinical yield. Conclusion The results of the study suggest that currently CT scans of the brain in unselected elderly patients have a low clinical yield and even in those CT scans which do yield results, only a small percentage of patients have their treatments changed after scan results.
The CT scan uses radiation for visualization which is many folds higher than the routine X-ray and excessive use can lead to potential harm. The study emphasizes the need for better clinical examination to diagnose patients, and proposes the need for guidelines to be created for its use.
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Hirano, L. A, Bogardus, S. T, Sanjay, S. , Leo-Summers, L. , and Sharon K. Inouye. (2006). Clinical yield of computed tomography brain scans in older general medical patients. Journal of American Geriatric society. 54, 587–592