Assessment of clinically significant urolithiasis positivity rate using CT KUB for suspected renal colic.

BACKGROUND: Unenhanced low-dose computed tomography of the kidneys, ureter and bladder (CT KUB) is the gold standard diagnostic imaging modality in the assessment of suspected renal colic. As the radiation dose is not negligible, it is important to monitor the diagnostic yield of CT KUBs. The aim of this study is to evaluate the diagnostic yield of CT KUB studies performed for suspected renal colic in patients presenting to the emergency department. METHODS: A retrospective review was performed of 500 patients who underwent CT KUB for suspected renal colic over a seven month period from June 2019 to January 2020. Clinical information and imaging was reviewed for each patient. Statistical analysis was performed using GraphPad Prism 8 (GraphPad Software, San Diego, CA, USA). RESULTS: Forty-nine percent of patients in the series were female (248/500) and the mean age was 45. The positivity rate for obstructing ureteral calculus was 34% (169/500). Concerningly, there was a significantly lower positivity rate in females compared to males (19% versus 48%; p < 0.0001) which raises the issue of unnecessary radiation exposure to this cohort. In the 200 female patients who were negative for obstructing urolithiasis, the mean age was 43. Females also had a significantly higher rate of negative CT KUB (62% versus 37%; p < 0.0001) where no underlying alternative pathology was diagnosed. CONCLUSIONS: Women are less likely than men to have obstructing urolithiasis on CT KUB for suspected renal colic. This difference is not accounted for by a higher rate of alternative diagnoses among female patients. The findings of this study should prompt clinicians to exercise caution when considering this imaging modality in this patient cohort.

A Real-World Cost-Effectiveness Study Evaluating Imaging Strategies for the Diagnostic Workup of Renal Colic in the Emergency Department.

Introduction Both non-contrast Computed Tomography (CT) and ultrasound (US) are used for the diagnosis of renal colic in the emergency department (ED). Although US reduces radiation exposure, its diagnostic accuracy is inferior to that of CT. In this context, data regarding the cost and organizational impact of these strategies represent essential elements in the choice of imaging; however, they remain poorly documented. Aim of the study The aim of this study was to compare the costs and effectiveness of diagnostic workup by US and CT for patients consulting with renal colic in the ED. Methods We conducted a monocentric real-life retrospective study of patients consulting for a renal colic in an ED between 1 July 2018 and 31 December 2018. We estimated length of stay (LOS), total hospital costs at 60 days including ED, and initial and repeat admissions. Patients with initial US in the ED were compared to patients with initial CT using inverse probability weighting of the propensity score calculated from demographic variables, vital parameters, and clinical presentation. We calculated the incremental cost effectiveness ratio as the difference in costs by the difference in LOS. The variability of the results was assessed using non-parametric bootstrapping. Results In this study, of the 273 patients included, 67 were patients assessed with US and 206 with CT. The average costs were €1159 (SD 1987) and €956 (SD 1462) for US and CT, respectively, and the ED LOS was 8.9 [CI 95% 8.1; 9.4] and 8.7 [CI 95% 7.9; 9.9] hours for US and CT, respectively. CT was associated with a decreased LOS by 0.139 [CI 95% -1.1; 1.5] hours and was cost-saving, with a €199 [CI 95% -745; 285] reduction per patient. Conclusion When imaging is required in the ED for suspected renal colic as recommended, there is real-life evidence that CT is a cost-effective strategy compared to US, reducing costs and LOS in the ED.

Imaging strategies for patients with suspicion of uncomplicated colic pain: diagnostic accuracy and management assessment.

OBJECTIVE: Compare different imaging scenarios in the diagnosis of uncomplicated renal colic due to urolithiasis (URCU). MATERIALS AND METHODS: A total of 206 prospectively included patients had been admitted with suspected URCU and had undergone abdominal plain film (APF), US and unenhanced CT after clinical STONE score evaluation. CT was the reference standard. We assessed sensitivity (Se), specificity (Spe) and Youden index for colic pain diagnosis, percentage of patients managed by urologic treatment with stone identified, percentage of alternative diagnoses (AD) and exposure to radiation, according to single imaging approaches, strategies driven by patient characteristics and conditional imaging strategies after APF and US. RESULTS: One hundred (48.5%) patients had a final diagnosis of URCU and 19 underwent urologic treatment. The conditional strategy, i.e. CT in patients who had no stone identified at US, had a perfect sensitivity and specificity. This enabled diagnosis of all stones requiring urology management while decreasing the number of CT exams by 22%. The strategy whereby CT was used when there was neither direct or indirect APF + US finding of colic pain nor alternative diagnoses in patients with a STONE score ≥ 10 had a sensitivity of 0.95 and a specificity of 0.99, identified 84% of stones managed by urologic treatment and decreased the number of CT examinations by 76%. CONCLUSION: In patients with clinical findings consistent with URCU, the use of ultrasound as first-line imaging modality, with CT restricted to patients with negative US and a STONE score ≥ 10, led to a sensitivity and specificity of above 95%, identified 84% of stones requiring urological management and reduced the number of CT scans needed by fourfold. KEY POINTS: • For diagnosis, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, provides both a sensitivity and specificity superior or equal to 95% and reduces the number of CT scans necessary by fourfold. • For management, the use of APF + US as first-line imaging, with CT restricted to patients with both a normal APF + US and a STONE score ≥ 10, maintains a 84% stone identification rate in urology-treated patients.

A prospective, matched comparison of ultra-low and standard-dose computed tomography for assessment of renal colic.

OBJECTIVE: To determine the diagnostic accuracy of ultra-low-dose computed tomography (ULDCT) compared with standard-dose CT (SDCT) in the evaluation of patients with clinically suspected renal colic, in addition to secondary features (hydroureteronephrosis, perinephric stranding) and additional pathological entities (renal masses). PATIENTS AND METHODS: A prospective, comparative cohort study was conducted amongst patients presenting to the emergency department with signs and symptoms suggestive of renal or ureteric colic. Patients underwent both SDCT and ULDCT. Single-blinded review of the image sets was performed independently by three board-certified radiologists. RESULTS: Among 21 patients, the effective radiation dose was lower for ULDCT [mean (SD) 1.02 (0.16) mSv] than SDCT [mean (SD) 4.97 (2.02) mSv]. Renal and/or ureteric calculi were detected in 57.1% (12/21) of patients. There were no significant differences in calculus detection and size estimation between ULDCT and SDCT. A higher concordance was observed for ureteric calculi (75%) than renal calculi (38%), mostly due to greater detection of calculi of <3 mm by SDCT. Clinically significant calculi (≥3 mm) were detected by ULDCT with high specificity (97.6%) and sensitivity (100%) compared to overall detection (specificity 91.2%, sensitivity 58.8%). ULDCT and SDCT were highly concordant for detection of secondary features, while ULDCT detected less renal cysts of <2 cm. Inter-observer agreement for the ureteric calculi detection was 93.9% for SDCT and 87.8% for ULDCT. CONCLUSION: ULDCT performed similarly to SDCT for calculus detection and size estimation with reduced radiation exposure. Based on this and other studies, ULDCT should be considered as the first-line modality for evaluation of renal colic in routine practice.

Application of Digital Tomosynthesis in the Diagnosis of Urolithiasis: Comparison with MDCT.

Objective: To investigate the diagnostic value of digital tomosynthesis in urolithiasis compared with multidetector computed tomography (MDCT). Subjects and Methods: This study received the approval of institutional review board and obtained the informed consents of all subjects. Fifty patients with acute renal colic and hematuria from February 2014 to February 2015 were enrolled. They underwent both MDCT and digital tomosynthesis. Images were interpreted by two experienced radiologists, and inter-reader agreement was assessed. The diagnostic performance of urinary stones with digital tomosynthesis and MDCT was compared. The entrance surface dose (ESD) in MDCT and digital tomosynthesis for patients was measured and compared. Results: No significant difference was found between digital tomosynthesis and MDCT in the diagnosis of urinary stones (X2 = 1.357, p > 0.05). The ESD in digital tomosynthesis was lower than that in both routine-dose and low-dose MDCT for patients (p < 0.05). Conclusions: Digital tomosynthesis has great diagnostic value in urolithiasis. Compared with MDCT, digital tomosynthesis can significantly decrease ESD for patients and financial loan with a similar detection rate.

Non-Contrast Enhanced Multi-Slice Ct-Kub In Renal Colic: Spectrum Of Abnormalities Detected On Ct Kub And Assessment Of Referral Patterns.

BACKGROUND: Renal colic is a common problem and significant number of patients presenting to ER, ED are suffering from acute or chronic renal colic. The conventional methods of investigating patients with renal colic are urine routine examination, plain radiograph for KUB (kidneys, ureters and bladder) and ultrasound followed by intravenous urography. Now a days non contrast enhanced computed tomography of kidneys, ureters and bladder is the first line investigation in suspected upper urinary tract obstruction. Radiation dose is one of the major limitations of CT KUB. Other limitations are cost and availability. The sensitivity and specificity of CT KUB is extremely high in the diagnosis of stones. METHODS: This cross-sectional descriptive study was conducted in the department of Radiology Ayub Medical Teaching Institution Abbottabad from 1st July 2017 to 30th May 2018. Information obtained from history, clinical examination and CT KUB, ultrasound were recorded in an approved and prescribed pro forma. RESULTS: Among total 350 patients, majority were male 66% and the age of study population ranged from 20 to 60 years. Most of the patients presented with flank pain and microscopic hematuria. Calculi were detected in 52 %. Patients with non obstructing stones were 63 %, ureteric stones and hydronephrosis were 22 %, ureterovesicle junction stone 4%. Patients with stones and incidental findings made 12.8% of the study population having abnormal CT KUB.. CONCLUSIONS: Non contrast enhanced CT KUB, performed in a suitable clinical scenario, is an excellent imaging investigation for patients having renal colic and the initial ultrasound is inconclusive. In majority of cases it identifies the cause of lumbar or pelvic pain. This modality has the added advantage of showing alternate causes for pain other than stones..

Bedside ultrasound and the assessment of renal colic: a review.

Renal colic is a common emergency department (ED) presentation. The use of CT in the diagnosis of renal colic has increased over the past two decades and is now the most common imaging modality used in many institutions. However, with growing concerns about cumulative radiation exposure, increasing healthcare costs and patient flow in EDs, alternative approaches may need to be considered. Point-of-care ultrasound may offer a radiation-free, rapid and cost-effective alternative. The authors reviewed the literature and synthesised some of the data comparing point-of-care ultrasound with CT scanning as well as some of the evidence for how it might be incorporated into a renal colic management strategy. It is concluded that there is enough evidence to define a rational algorithm for renal colic management. A prospectively validated algorithm would greatly assist primary care and emergency practitioners while reducing costs and radiation dose.

Diagnostic value of renal resistive index for the assessment of renal colic.

INTRODUCTION: The aim of this study was to investigate the value of renal resistive index (RI) for the assessment of renal colic and to determine whether it is predictive of renal stone disease. METHODS: A total of 70 participants were included in the research study. Group 1 comprised 43 patients with acute unilateral ureteral obstruction due to a stone disease (G1), while Group 2 consisted of seven patients with flank pain without stone disease (G2) and the control group comprised 20 healthy individuals with two normal kidneys (G3). Urinalysis, abdominal plain film radiography, conventional ultrasonography (US) and colour Doppler US were performed in all three groups. RI was calculated for all patients using Doppler US. The RI values in G1 were then compared with those in G2 and the control group. RESULTS: There were statistically significant differences in the RI between the stone-positive group and stone-free groups (0.71 +/- 0.07 for G1; 0.69 +/- 0.06 for G2; 0.62 +/- 0.03 for G3, p-value < 0.05). CONCLUSION: RI measurement using Doppler US can be effectively used for the assessment of renal colic patients by non-invasive means.

Abdominopelvic CT increases diagnostic certainty and guides management decisions: a prospective investigation of 584 patients in a large academic medical center.

OBJECTIVE: The objective of our study was to prospectively determine how CT affects physicians' diagnostic certainty and management decisions in the setting of patients with nontraumatic abdominal complaints presenting to the emergency department. SUBJECTS AND METHODS: We included 584 patients presenting with nontraumatic abdominal complaints to the emergency department from November 2006 through February 2008. Emergency department clinicians were prospectively surveyed both before abdominal CT (pre-CT) and after abdominal CT (post-CT) to determine the leading diagnosis, the diagnostic certainty, and the management decisions. Changes were assessed by Fisher's exact test and the log likelihood ratio. RESULTS: The most common diagnoses were renal colic (119/584, 20.4%) and intestinal obstruction (80/584, 13.7%). CT altered the leading diagnosis in 49% of the patients (284/584, p < 0.00001) and increased mean physician diagnostic certainty from 70.5% (pre-CT) to 92.2% (post-CT) (p < 0.001; log likelihood ratio, 2.48). The management plan was changed by CT in 42% (244/583) (p < 0.0001). Physicians planned to admit 75.3% of the patients (440/584) to the hospital before CT; that plan was changed to hospital discharge with follow-up in 24.1% of patients (106/440) after CT. Surgery was planned for 79 patients before CT, whereas hospital discharge was planned for 25.3% of these patients (20/79) after CT. CONCLUSION: In the management of patients presenting to the emergency department with nontraumatic abdominal complaints, CT changes the leading diagnosis, increases diagnostic certainty, and changes potential patient management decisions.

Assessment of referral patterns for CT KUB in a tertiary setting.

The purpose of this study was to assess the referral patterns and the use of unenhanced renal tract CT (CT KUB) for investigating patients presenting with clinically suspected renal colic. We retrospectively reviewed 500 consecutive CT KUB studies requested for suspected renal colic carried out at a single institution between December 2006 and July 2007. Follow-up radiology reports and discharge summaries on the hospital clinical Intranet were also reviewed. Studies were analysed for characteristics including patient demographics, referring clinical team, time of referral, final diagnosis and requirement for further imaging. The majority of requests were from Emergency (ED) or Urology Departments (49%, 245 out of 500, and 37%, 186 out of 500, respectively). The positive rate for urolithiasis was 67% (337 out of 500), the negative rate was 25% (123 out of 500), and 8% (40 out of 500) of patients had alternative significant findings. Female patients were more likely to have a negative study than male patients (35 versus 20%, P < 0.0001) and more likely to have alternative significant pathology (12 versus 6%, P < 0.0001). Patients referred by specialities other than Urology and ED were more likely to be female and have a negative or alternative finding (P < 0.0001). CT KUB is a widely used first method of investigation for patients with suspected renal colic with a high positive predictive value allowing rapid diagnosis and intervention. However, given the high rate of negative or alternative findings on CT KUB in young women, especially those referred by specialities other than ED or Urology, ultrasound should be considered as an alternative imaging method to minimise unnecessary radiation exposure.