A conservative screening approach to kidney disease before contrast-enhanced computed tomography in outpatient population.

OBJECTIVE: To determine the incidence of abnormal renal function in an outpatient population referred for contrast-enhanced computed tomography (CECT) and assess the risk factors that could be used to eliminate superfluous estimated glomerular filtration rate (eGFR) testing. PATIENTS AND METHODS: The following risk factors were assessed in random patients referred for outpatient CECT: age >60 years, diabetes mellitus, hypertension, anemia, congestive heart failure, and a history of kidney/urological disease or renal surgery. The patients' serum creatinine and eGFR levels, gender, and the type of CECT were recorded. RESULTS: The study included 500 patients (mean age 50±16 years). Among them, 36 (7.2%) patients had an eGFR <60 ml/min/1.73 m2 of which 31 (6.2%) had an eGFR of 59-45 ml/min/1.73 m2 and 5 (1%) patients an eGFR <45 ml/min/1.73 m2. No patients had an eGFR <30 ml/min/1.73 m2. There was a statistically significant association between an abnormal eGFR and age >60 years, diabetes mellitus, hypertension, and chronic kidney disease (p<0.05). By selecting only, the patients with one of the identified risk factors for eGFR assessment before CECT, all the patients with an abnormal eGFR (<60 ml/min/1.73 m2) were detected with sensitivity and a negative predictive value of 100%. CONCLUSIONS: Patients with an abnormal eGFR can be detected with sensitivity and a negative predictive value of 100% using our screening approach before CECT, and superfluous eGFR testing can thus be reduced by approximately 50% with concomitant cost savings. Outpatients without any risk factors should be excluded from routine renal function assessment before CECT.

Radiation doses in chest, abdomen and pelvis CT procedures.

Computed tomography (CT) scanning is recognised as a high-radiation dose modality and estimated to be 17 % of the radiological procedure and responsible for 70 % of medical radiation exposure. Although diagnostic X rays provide great benefits, their use involves some risk for developing cancer. The objectives of this study are to estimate radiation doses during chest, abdomen and pelvis CT. A total of 51 patients were examined for the evaluation of metastasis of a diagnosed primary tumour during 4 months. A calibrated CT machine from Siemens 64 slice was used. The mean age was 48.0 ± 18.6 y. The mean patient weight was 73.8 ± 16.1 kg. The mean dose-length product was 1493.8 ± 392.1 mGy cm, Volume CT dose index (CTDI vol) was 22.94 ± 5.64 mGy and the mean effective dose was 22.4 ± 5.9 mSv per procedure. The radiation dose per procedure was higher as compared with previous studies. Therefore, the optimisation of patient's radiation doses is required in order to reduce the radiation risk.