Aggarwal G, Adhikary SD. Assessment of the efficacy of reduced-radiation noncontrast computed tomography scan compared with the standard noncontrast computed tomography scan for detecting urolithiasis: A prospective single-center study.
Curr Urol 2023;
17:18-24. [PMID:
37692141 PMCID:
PMC10487294 DOI:
10.1097/cu9.0000000000000162]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 08/09/2022] [Indexed: 11/09/2022] Open
Abstract
Background
Noncontrast computed tomography (CT) scan of the kidneys, ureter and bladder is the standard investigative modality for diagnosing and following up patients with urolithiasis. With each scan, a patient receives radiation of 18-34 mGy. Dose considerations become pertinent because of a 10% lifetime incidence rate and higher than 50% risk of recurrence, necessitating repeated imaging in the lifetime of a stone former. Hence, this study aimed to assess the sensitivity of "reduced-radiation" CT imaging by altering scan settings to lower than the "standard" norms.
Materials and methods
Altogether, 222 patients (255 "kidney-ureter" stone-bearing units or "renal units") with urolithiasis and patients undergoing CT for other reasons with incidental findings of renal/ureteric calculi between 2017 and 2019 were included. All patients were subjected to 3 sequential scans at tube current settings of 250 mA (CT-N/Standard), 100 mA (CT-100), and 50 mA (CT-50) at a constant voltage of 120 kV. Their clinicodemographic and radiological findings were recorded and assessed for significance.
Results
Of the 255 renal units, 117 were between 30 and 44 years of age, 75% were men. Of the 255 patients, 178 (70.1%) reported a first stone episode and 77 had recurrence. Lower ureteric calculi were predominant (40.4%). All calculi were identified on CT-N; CT-100 failed to detect calculi in 1 patient, and CT-50 failed in 3 patients, where all calculi were <3 mm in size. Meanwhile, none were undetected among patients with obesity. The sensitivity was 99.61% for the CT-100 and 98.82% for the CT-50, which indicated a 2.5 and 5 times lower radiation and dose/length, respectively, than CT-N.
Conclusions
The reduced-radiation CT scan is safe, sensitive, and accurate for the diagnosis and follow-up of patients with urolithiasis with significantly lower radiation exposures. Our study lays the foundation to accept low-dose CT in general and CT-50 in particular, as the new "standard of care," and attempt further dose reduction without loss of diagnostic efficacy.
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