CT findings in suspected renal colic patients undergoing unenhanced low-dose multi-detector computed tomography.

Abstract

Background Acute flank pain is one of the most painful events one can be involved in. The most common cause for this is usually urinary tract calculi also known as urolithiasis. There is a global rise in urolithiasis incidences and the same trend is being seen in Kenya with diagnostic tools awareness and use being a challenge in the emergency departments. However other non-genital urinary conditions and non-calculus causes can have similar presentation. Due to the nature and acuteness of the presentation of suspected renal colic as an emergency a diagnostic tool that is highly sensitive, specific and rapid is required in such incidences. CT-KUB has a high accuracy in detecting ureteric stones and plays a vital role in identifying significant alternative diagnoses therefore guiding the proper management of the patient. Aim The goal of this study was to determine the CT findings in patients undergoing unenhanced CT KUB for suspected renal colic. Methodology Prospective cross-sectional descriptive study was done at the MP Shah hospital and the Kenyatta national hospital department of radiology. The study was carried out over a period of 6 months, from October 2019 to March 2020. Patients who visited the emergency department or referred by the urologist with suspected renal colic to undergo unenhanced low dose CTKUB and fit the inclusion criteria for the duration of the study were included in this study. One hundred and two patients meeting the inclusion criteria were selected for this study. Results One hundred and two patients underwent unenhanced low dose MDCT KUB. All this patients were included in the statistical analysis. These were 55 male and 47 female with age range of 19 -72 years. The mean age was 41.7 (SD 12.5) years and the median age was 40 (IQR 33-49) years. Thirty six of the patients [35%] had ureteric calculi, Thirty five [ 34%] were normal studies with 31 [31 %] patients having alternative diagnosis. The study demonstrated that unenhanced low dose MDCT is the imaging of choice for evaluation of suspected renal colic as it is able to correctly identify ureteric calculi and also identify alternate diagnoses for the proper management of the patients. Conclusion.  Unenhanced low dose MDCT is the imaging of choice for evaluation of suspected renal colic as it can correctly identify urolithiasis and is able to significantly identify other causes of acute pain that may mimic renal colic.  Presence of secondary radiological signs which was positive in 78% of the positive cases for urolithiasis is a strong correlation and a significant finding in aiding the reporting radiologist in making and confirming the diagnoses. They also give the confidence that obstruction is caused by a calculus therefore an important diagnostic clue. Recommendations.  Adoption of Low dose Multidetector CT KUB as the first line imaging of choice for evaluation of suspected renal colic patients as its able to correctly identify urolithiasis and other alternate diagnosis with reduction of radiation dose exposure to the patient.  Proper and comprehensive clinical history and examination from referring clinician can help in improve on discriminating the patients to undergo CT KUB and utilization of other modalities like ultrasound especially on female patients as demonstrated by the high number of female patients with gynecological alternate diagnosis in this study.  Future studies involving the dual energy MDCT to determine calculus composition is warranted for future utilization of CT IN urolithiaisis imaging.