Ureteral Stones: Implementation of a Reduced-Dose CT Protocol in Patients in the Emergency Department with Moderate to High Likelihood of Calculi on the Basis of STONE Score

[Imaging for urolithiasis]

The substantial reduction of radiation exposure using (ultra-)low dose programs in native computed tomographic imaging has led to considerable changes in imaging diagnostics and treatment planning in urolithiasis in recent years. In addition, especially in Germany, ultrasound diagnostics is highly available in terms of equipment and with increasing expertise. This can largely replace the previous radiation-associated procedures in emergency and follow-up diagnostics, but also in intraoperative imaging, e.g., in percutaneous stone therapy (intraoperative fluoroscopy). This is reflected in the international guidelines, which recommend these two modalities as first-line diagnostics in all areas mentioned. Continuous technical development enables ever higher resolution imaging and thus improved diagnostics with high sensitivity and specificity. This also enables reliable imaging of particularly vulnerable patient groups, such as children or pregnant women. In addition, methods from the field of artificial intelligence (AI; machine learning, deep learning) are increasingly being used for automated stone detection and stone characterization including its composition. Furthermore, AI models can provide prognosis models as well as individually tailored treatment, follow-up, and prophyaxis. This will enable further personalization of diagnostics and therapy in the field of urolithiasis.

A Systematic Review of Interventions to Reduce Computed Tomography Usage in the Emergency Department

STUDY OBJECTIVE

Unnecessary computed tomography (CT) scans burden the health care system, leading to increased emergency department (ED) wait times and lengths of stay, costing almost a billion dollars annually. This study aimed to describe ED-based interventions that are most effective at reducing CT imaging while maintaining diagnostic accuracy and patient safety.

METHODS

Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials, and Google Scholar were searched until December 31, 2020. Randomized and nonrandomized studies that assessed the effect of an ED-based intervention on CT scan usage were included. Abstract screening, data extraction, and quality assessment were conducted in duplicate. The Grading of Recommendation Assessment, Development and Evaluation framework, with the Risk of Bias 2 and Risk of Bias in Nonrandomized Studies - of Interventions tools, was used to determine the certainty of evidence. Significant clinical and statistical heterogeneity precluded meta-analysis; hence, a narrative synthesis was conducted.

RESULTS

A total of 149 studies were included of 5,667 screened abstracts, with substantial interrater reliability among reviewers (Cohen's κ>0.60). The CT reduction strategies were categorized into 15 single and 11 multimodal interventions by consensus review. Interventions that consistently reduced CT usage included diagnostic pathways, alternative test availability, specialist involvement, and provider feedback. Family/patient education, clinical decision support tools, or passive guideline dissemination did not consistently reduce usage. Only 44% of studies reported unintended consequences of reduction strategies; however, these showed no increase in missed diagnoses or patient harm. The interventions that engaged multiple specialties during planning/implementation had a greater reduction effect than ED only. The certainty of evidence for the primary outcome was very low.

CONCLUSION

Multidisciplinary-led interventions that provided an alternative to CT imaging were the most effective at reducing usage and did so without compromising patient safety.

Imaging in stone diagnosis and surgical planning

PURPOSE OF REVIEW

Radiological imaging techniques and applications are constantly advancing. This review will examine modern imaging techniques in the diagnosis of urolithiasis and applications for surgical planning.

RECENT FINDINGS

The diagnosis of urolithiasis may be done via plain film X-ray, ultrasound (US), or contrast tomography (CT) scan. US should be applied in the workup of flank pain in emergency rooms and may reduce unnecessary radiation exposure. Low dose and ultra-low-dose CT remain the diagnostic standard for most populations but remain underutilized. Single and dual-energy CT provide three-dimensional imaging that can predict stone-specific parameters that help clinicians predict stone passage likelihood, identify ideal management techniques, and possibly reduce complications. Machine learning has been increasingly applied to 3-D imaging to support clinicians in these prognostications and treatment selection.

SUMMARY

The diagnosis and management of urolithiasis are increasingly personalized. Patient and stone characteristics will support clinicians in treatment decision, surgical planning, and counseling.

Is This Your Stone? Distinguishing Phleboliths and Nephroliths on Imaging in the Emergency Department Setting

BACKGROUND

Ureteral stones are a common diagnosis in the emergency department (ED) setting, often found with computed tomography (CT). The high frequency of phleboliths can confound ureteral stone diagnosis on CT imaging.

OBJECTIVE

This article provides a narrative review of the etiological, epidemiological, and radiological distinctions between ureteral stones and phleboliths for appropriate ED diagnosis and management.

DISCUSSION

Multiple studies demonstrate phleboliths, benign calcified thrombi largely in pelvic vasculature, are found at frequencies equal to or greater than those of ureteral stones on CT imaging. The calcified foundation of phleboliths and most ureteral stones, as well as the close proximity of the distal ureters to pelvic vasculature, can cause consternation in the proper diagnosis of ureteral stones in the patient with abdominal pain. Radiological findings of circumferential ureteral soft tissue edema ("rim sign") and an irregular tapering soft tissue mass ("comet tail sign") can suggest a ureteral and phlebolith etiology, respectively. These signs demonstrate high specificity but low sensitivity, and clinicians must use history, examination, and secondary signs on imaging to differentiate ureteral stones from phleboliths.

CONCLUSIONS

Phleboliths are a common finding on CT imaging. Radiological findings of rim sign and comet tail sign may help to differentiate phleboliths and ureteral stones; however, their low sensitivity and inconsistent presentation should prompt greater reliance on other signs of ureteral obstruction to aid in diagnosis of undifferentiated pelvic calcifications.

Expanding the Utilization of Low-Dose Computed Tomography in Plastic and Reconstructive Surgery Based on Validated Practices Among Surgical Specialties

INTRODUCTION

As computed tomography (CT) usage increases, so have concerns over radiation-induced malignancy. To mitigate these risks, low-dose CT (LDCT) has emerged as a versatile alternative by other specialties, although its use in plastic surgery remains sparse. This study aimed to investigate validated uses of LDCT across surgical specialties and extrapolate these insights to expand its application for plastic surgeons.

METHODS

A systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using search terms "low dose CT" OR "low dose computed tomography" AND "surgery," where the name of each surgical specialty was substituted for word "surgery" and each specialty term was searched separately in combination with the 2 CT terms. Data on radiation dose, outcomes, and level of evidence were collected. Validated surgical applications were correlated with similar procedures and diagnostic tests performed routinely by plastic surgeons to extrapolate potential applications for plastic surgeons.

RESULTS

A total of 3505 articles were identified across surgical specialties, with 27 ultimately included. Depending on the application, use of LDCT led to a 25% to 97% reduction in radiation dose and all studies reported noninferior image quality and diagnostic capability compared with standard-dose CT. Potential identified uses included the following: evaluation of soft tissue infections, preoperative and postoperative management of facial and hand fractures, flap design, 3D modeling, and surgical planning.

DISCUSSION

Low-dose CT is a valid imaging alternative to standard-dose CT. Expanded utilization in plastic surgery should be considered to minimize the iatrogenic effects of radiation and to promote patient safety without compromising outcomes.

The prospective evaluation of the effectiveness of scoring systems in the emergency department in cases with suspected ureteral stones: STONE? CHOKAI?

INTRODUCTION

This study evaluates the effectiveness of CHOKAI and STONE scores in patients presenting to the emergency department with ureteral stones.

METHODS

Patients over the age of 18 who were admitted to the emergency department with flank pain, groin pain, scrotal pain, and hematuria and who were performed non-contrast abdominal computed tomography (CT) for diagnostic imaging were included. The numeric pain, CHOKAI, and STONE scores of the patients were calculated. The effectiveness of these scoring systems in the presence of stones was examined.

RESULTS

A total of 105 patients were included in the study. In the analysis performed to investigate whether there was a difference between the numeric pain, STONE, and CHOKAI scores in terms of the presence of stones on CT, it was seen that the CHOKAI score was significantly different from the others (p < 0.001). A significant positive correlation was found between the CHOKAI score and stone size (r = 0.343, p < 0.001).When the cut-off value of the CHOKAI score was >7, the sensitivity was found to be 60.49%, and specificity was 83.33%. The cut-off value for the STONE score was >8 with a sensitivity of 70.37% and specificity of 58.33%. The corresponding area under curve values for the CHOHAI and STONE scores was 0.788 (p < 0.0001) and 0.615 (p = 0.087). Male sex, the CHOKAI, and STONE scores were the independent risk factors for ureteral stone. A significant positive correlation was found between the CHOKAI score and stone size (r = 0.343, p < 0.001).

CONCLUSION

The CHOKAI score has a higher performance than the STONE score in detecting the presence of ureteral stones.

NEW KNOWLEDGE ADDED BY THIS STUDY

The CHOKAI score has a higher performance than the STONE score in detecting the presence of ureteral stones. Especially in countries such as Turkey, where there are no specific racial differences, the STONE score may be diagnostically insufficient. The CHOKAI score shows the presence of the patient's stone and positively correlates with the size of the stone and the stone location.

IMPLICATION FOR CLINICAL PRACTICE OR POLICY

In the functioning of the emergency department, it is important to make the differential diagnosis of patients quickly and provide effective treatment. The use of diagnostic scoring systems saves time for the emergency physician in the differential diagnosis phase and guides in terms of applying for possible additional imaging methods.

What are the clinical effects of the different emergency department imaging options for suspected renal colic? A scoping review

OBJECTIVES

Clinicians have minimal guidance regarding the clinical consequences of each radiologic imaging option for suspected renal colic in the emergency department (ED), particularly in relation to patient-centered outcomes. In this scoping review, we sought to identify studies addressing the impact of imaging options on patient-centered aspects of ED renal colic care to help clinicians engage in informed shared decision making. Specifically, we sought to answer questions regarding the effect of obtaining computed tomography (CT; compared with an ultrasound or delayed imaging) on safety outcomes, accuracy, prognosis, and cost (financial and length of stay [LOS]).

METHODS

We conducted a comprehensive search using Pubmed, EMBASE, Web of Science conference proceedings index, and Google Scholar, identifying studies pertaining to renal colic, urolithiasis, and ureterolithiasis. In a prior qualitative study, stakeholders identified 14 key questions regarding renal colic care in the domains of safety, accuracy, prognosis, and cost. We systematically screened studies and reviewed the full text of articles based on their ability to address the 14 key questions.

RESULTS

Our search yielded 2570 titles, and 68 met the inclusion criteria. Substantial evidence informed questions regarding test accuracy and radiation exposure, but less evidence was available regarding the effect of imaging modality on patient-oriented outcomes such as cost and prognosis (admissions, ED revisits, and procedures). Reviewed studies demonstrated that both standard renal protocol CT and low-dose CT are highly accurate, with ultrasound having lower accuracy. Several studies found that ureterolithiasis diagnosed by ultrasound was associated with overall reduced radiation exposure. Existing studies did not suggest choice of imaging influences prognosis. Several studies found no substantial differences in monetary cost, but LOS was found to be shorter if a diagnosis was made with point-of-care ultrasound.

CONCLUSION

There is a plethora of data related to imaging accuracy. However, there is minimal data regarding the effect of CT on many patient-centered outcomes. Further research could improve the patient-centeredness of ED care.

Effect of obesity on ability to lower exposure for detection of low-attenuation liver lesions

Purpose

The purpose of this study was to assess the effect of obesity and iterative reconstruction on the ability to reduce exposure by studying the accuracy for detection of low‐contrast low‐attenuation (LCLA) liver lesions on computed tomography (CT) using a phantom model.

Methods

A phantom with four unique LCLA liver lesions (5‐ to 15‐mm spheres, –24 to –6 HU relative to 90‐HU background) was scanned without (“thin” phantom) and with (“obese” phantom) a 5‐cm thick fat‐attenuation ring at 150 mAs (thin phantom) and 450 mAs (obese phantom) standard exposures and at 33% and 67% exposure reductions. Images were reconstructed using standard filtered back projection (FBP) and with iterative reconstruction (Adaptive Model‐Based Iterative Reconstruction strength 3, ADMIRE). A noninferiority analysis of lesion detection was performed.

Results

Mean area under the curve (AUC) values for lesion detection were significantly higher for the thin phantom than for the obese phantom regardless of exposure level (P < 0.05) for both FBP and ADMIRE. At 33% exposure reduction, AUC was noninferior for both FBP and ADMIRE strength 3 (P < 0.0001). At 67% exposure reduction, AUC remained noninferior for the thin phantom (P < 0.0035), but was no longer noninferior for the obese phantom (P ≥ 0.7353). There were no statistically significant differences in AUC between FBP and ADMIRE at any exposure level for either phantom.

Conclusions

Accuracy for lesion detection was not only significantly lower in the obese phantom at all relative exposures, but detection accuracy decreased sooner while reducing the exposure in the obese phantom. There was no significant difference in lesion detection between FBP and ADMIRE at equivalent exposure levels for either phantom.

Application of decision rules on diagnosis and prognosis of renal colic: a systematic review and meta-analysis

Renal colic is a prevalent emergency department presentation resulting from urolithiasis. Clinical decision rules for the diagnosis of urolithiasis were developed to help clinicians with better judgment. In this systematic review, we assessed the performance of prediction rules on urolithiasis diagnosis and prognosis. MEDLINE, Embase, Web of Science, and Scopus were searched for studies on the performance of a clinical decision tool for diagnosis or prognosis of urolithiasis. Performance and accuracy of the rules were the key outcomes of interest. Databases were searched from inception to March 2019. Of the 4980 articles reviewed, 28 studies were included in the present analysis. Twenty-one studies were on urolithiasis diagnosis (including eight studies on STONE rule), and 10 studies reported urolithiasis outcomes. Studies were at low to moderate risk of bias. The pooling of data on STONE showed that the prevalence of urolithiasis in low, moderate, and high risk groups were: 12% (95% confidence interval 9%-15%), 53% (95% confidence interval 43%-62%), and 83% (95% confidence interval 75%-91%), respectively. In the high risk score group, prevalence of clinically important alternative diagnosis was 1% (95% confidence interval 0%-2%) and 11% (95% confidence interval 8%-13%) of patients needed intervention. STONE scoring system is useful in estimating the prevalence of urolithiasis but high heterogeneity among the studies makes it unsuitable for application. Other decision tools were poorly studied and cannot be recommended for clinical use.

External validation of STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones in the Turkish population

Background:

Scoring systems seem to be effective in the management of patients with uncomplicated ureteral stones. However, their efficiency may differ by population.

Objectives:

We aimed to validate STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones in the Turkish population.

Methods:

We conducted a retrospective chart review between 01 February 2018 and 30 November 2018, in an academic emergency department. Demographics, laboratory findings, and radiologic tests of patients with flank pain were obtained. Computed tomography was used as the gold standard for the diagnosis of ureteral stones. STONE, modified STONE, and CHOKAI scores were calculated for each patient. The performance of the scoring systems was compared in terms of their specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, negative predictive value, and positive predictive value.

Results:

A total of 157 patients were included in the study. The mean age was 38.47 ± 14.87 years, and 103 (65.6%) of the patients were males. The prevalence of ureteral stones was 84.0%, 88.9%, and 85.0% in the high-risk patients and 12%, 9.4%, and 22.7% in the low-risk patients for the STONE, modified STONE, and CHOKAI scores, respectively. Area under the curve values for the STONE, modified STONE, and CHOKAI scores were 0.776 (p = 0.001; 0.692–0.860 95% confidence interval), 0.825 (p < 0.001; 0.749–0.901 95% confidence interval), and 0.869 (p < 0.001; 0.806–0.932 95% confidence interval), respectively. The specificity and sensitivity values of STONE, modified STONE, and CHOKAI scores for the diagnosis of ureteral stones were 64.71, 71.70; 70.59, 87.74; and 66.67, 90.57, respectively.

Conclusion:

The CHOKAI score displayed the best performance compared to STONE and modified STONE in diagnosing ureteral stones in the Turkish population.

Using the T11 vertebra to minimise the CT-KUB scan field

OBJECTIVES

Computed tomography scans of the kidney, ureters, and bladder (CT-KUB) are crucial in investigating urinary calculi but impart a substantial radiation doses. Radiation can be limited by minimising the scanning field to the necessary area (i.e. from the kidneys to urethra). Before auditing, the superior limit of CT-KUB scans had not been formally clarified at our trust. Consistently ensuring the upper limit of scans is at or below T10 has been shown to be a viable method of performing CT-KUB scans. This study aimed to assess the overscan length of CT-KUB investigations and modify practice accordingly to minimise it. There were two standards that were set for CT-KUB scanning. First, the mean percentage overscan length (i.e. percentage of the scan above the kidneys) should be <15%. Second, all scans should include the superior borders of both kidneys.

METHODS

90 consecutive CT-KUB scans for ureteric calculus were retrospectively investigated using IMPAX software in the first phase of data collection. After these data were analysed, a newly devised protocol using T11 as the superior scan limit was delivered to radiographers in the department. and 105 in the second phase (re-audit). The analysis parameters were: percentage overscan length, distance between diaphragm and upper border of kidneys, vertebral level at which the scan commenced, and whether both kidneys were fully included.

RESULTS

In the first phase, overscan of >15% was present in 94.4% of scans. The mean percentage overscan length was 28.2%. The superior vertebral limit of 59% of scans was at T10 or below and a lower superior vertebral limit correlated with decreasing overscan. 99% of scans fully included both kidneys. In the second phase (3 months later), the mean overscan percentage reduced to 10.6% (standard deviation = 4.4%). Excessive overscan affected 35.2% of scans. The superior vertebral limit of 8% of scans was at T10 or below. 100% of scans fully included both kidneys.

CONCLUSION

Excessive overscanning was due to inconsistent technique in capturing CT-KUB scans. Before this audit, the superior limit of CT-KUB scans had not been formally clarified at our trust. By successfully standardising the process with a reproducible method, the overscan target was comfortably met. Therefore, patient dose was minimised without compromising scan quality.

ADVANCES IN KNOWLEDGE

This audit has successfully shown a feasible standardised protocol for CT-KUB investigations which can be used to minimise overscanning of patients.

Optical puncture combined with balloon dilation PCNL vs. conventional puncture dilation PCNL for kidney stones without hydronephrosis: a retrospective study

Background

Accurate puncture and dilation of the target kidney calices for percutaneous nephrolithotomy (PCNL) can be difficult. This study aimed to investigate the advantages of PCNL using optical puncture (i.e. the puncture is visualized on a screen as seen through the needle) combined with balloon dilation vs. conventional puncture methods.

Methods

This was a retrospective study of 58 consecutive patients with kidney stones without hydronephrosis and treated at the Minimally Invasive Urology Center of Zhejiang Provincial People’s Hospital between 10/2016 and 12/2017. Twenty-one patients underwent optical puncture combined with balloon dilation PCNL. Thirty-seven patients underwent conventional puncture instrument dilation PCNL (controls). Success rate, tubeless rate, blood loss, pain, and complications were compared between the two groups.

Results

The one-time puncture success rate (95.2% [20/21] vs. 67.6% [25/37], P = 0.02) and the postoperative tubeless rate (81.0% [17/21] vs. 54.1% [20/37], P = 0.04) were higher in the optical puncture group compared with controls. The average postoperative hemoglobin reduction was smaller (1.13 ± 0.63 vs. 1.56 ± 0.59 g/dL, P = 0.01), the postoperative VAS score was lower (1.6 ± 0.9 vs. 2.5 ± 1.2, P = 0.004), the rate of postoperative analgesic use was lower (14.3% [3/21] vs. 40.5% [15/37], P = 0.04), and the postoperative mean hospitalization days was shorter (3.7 ± 0.9 vs. 4.4 ± 0.8, P = 0.005) in the optical puncture group vs. controls. There was no case of urinary sepsis, blood transfusion, perirenal hematoma, pleural injury, and visceral organ damage.

Conclusions

Optical puncture combined with balloon dilation PCNL could be associated with good therapeutic effect and low frequency of complications for the treatment of kidney stones without hydronephrosis.

Aktualisierung der S2k-Leitlinie zur Diagnostik, Therapie und Metaphylaxe der Urolithiasis (AWMF Registernummer 043-025)

Die Zunahme des medizinischen Wissens, technische Neuerungen gemeinsam mit demographischem Wandel stellen eine Herausforderung an die Neukonzeption von Leitlinien und klinischen Studien dar. Die vorliegende S2k-Leitlinie, die sich ausschließlich mit Nieren- und Harnleitersteinen beschäftigt, soll die Behandlung von Harnsteinpatienten in Klinik und Praxis unterstützen, aber auch Patienteninformationen zur Urolithiasis geben. Die zunehmende interdisziplinäre Zusammenarbeit in der Steintherapie zeigt sich auch an der Anzahl beteiligter Fachgruppen und Arbeitsgemeinschaften in der Erstellung des neuen Leitlinienupdates. Die vorliegende, aus einem interdisziplinären Konsensusprozess hervorgegangene S2k-Leitlinie stellt die aktuellen Empfehlungen praxisnah dar und gibt Entscheidungshilfen für Diagnostik‑, Therapie- und Metaphylaxemaßnahmen auf Basis von Expertenmeinungen und verfügbaren Evidenzgrundlagen aus der Literatur.

Imaging in Suspected Renal Colic: Systematic Review of the Literature and Multispecialty Consensus

BACKGROUND

Renal colic is common, and CT is frequently utilized when the diagnosis of kidney stones is suspected. CT is accurate but exposes patients to ionizing radiation and has not been shown to alter either interventional approaches or hospital admission rates. This multi-organizational transdisciplinary collaboration sought evidence-based, multispecialty consensus on optimal imaging across different clinical scenarios in patients with suspected renal colic in the acute setting.

METHODS

In conjunction with the American College of Emergency Physicians (ACEP) eQual network, we formed a nine-member panel with three physician representatives each from ACEP, the ACR, and the American Urology Association. A systematic literature review was used as the basis for a three-step modified Delphi process to seek consensus on optimal imaging in 29 specific clinical scenarios.

RESULTS

From an initial search yielding 6,337 records, there were 232 relevant articles of acceptable evidence quality to guide the literature summary. At the completion of the Delphi process consensus, agreement was rated as perfect in 15 (52%), excellent in 8 (28%), good in 3 (10%), and moderate in 3 (10%) of the 29 scenarios. There were no scenarios where at least moderate consensus was not reached. CT was recommended in 7 scenarios (24%), with ultrasound in 9 (31%) and no further imaging needed in 12 (45%).

SUMMARY

Evidence and multispecialty consensus support ultrasound or no further imaging in specific clinical scenarios, with reduced-radiation dose CT to be employed when CT is needed in patients with suspected renal colic.

External validation of the CHOKAI score for the prediction of ureteral stones: A multicenter prospective observational study

OBJECTIVE

The CHOKAI and STONE scores are clinical prediction rules to predict ureteral stones in patients presenting with renal colic. Both systems contribute to reducing diagnostic radiation exposure; however, few studies have compared the two scoring systems. Therefore, we aimed to compare these systems and assess their diagnostic accuracy for ureteral stones.

METHODS

This was a multicenter prospective observational study performed between 2017 and 2018, including patients aged >15 years with renal colic and suspected with ureteral stones. We calculated the CHOKAI and STONE scores of each patient based on their medical interviews and physical and laboratory findings. Primary outcome was differences in the area under the receiver operating characteristic curve in each model, and secondary outcome was diagnostic accuracy at the optimal cut-off point.

RESULTS

Of the 124 patients included, 84 were diagnosed with ureteral stones. The area under the curve of the CHOKAI score was 0.95, showing a sensitivity of 0.93, specificity of 0.90, positive likelihood ratio of 9.3, and negative likelihood ratio of 0.079, at an optimal cut-off point of 6. The area under the curve of the STONE score was 0.88, showing a sensitivity of 0.68, specificity of 0.90, positive likelihood ratio of 6.8, and negative likelihood ratio of 0.36, at an optimal cut-off point of 9. Thus, the area under the curve was significantly higher for the CHOKAI score than for the STONE score (p = 0.0028).

CONCLUSIONS

The CHOKAI score has a diagnostic performance superior to that of the STONE score in this population.

Recent surgical treatments for urinary stone disease in a Korean population: National population-based study

OBJECTIVES

To provide surgical treatment trends for urinary stone disease in Korea.

METHODS

We analyzed medical service claim data of surgical treatments to urinary stone disease submitted by medical service providers from the Health Insurance Review and Assessment Service from 2009 to 2016.

RESULTS

There was a significantly increasing trend among outpatients and inpatients for urinary stone disease from 2009 to 2016 (R²  = 0.643, P = 0.017; R²  = 0.575, P = 0.029). The number of shock wave lithotripsy for treating urinary stone disease increased by 16% from 89 553 in 2009 to 104 013 in 2016 (R²  = 0.684). The number of ureteroscopic lithotripsy increased by 97% from 6106 in 2009 to 12 057 in 2016 (R²  = 0.99). The number of flexible ureteroscopic lithotripsy increased by 16-fold from 219 in 2009 to 3712 in 2016 (R²  = 0.756). The number of percutaneous nephrolithotomy increased by 99.7% from 919 in 2009 to 1835 in 2016 (R²  = 0.987). The use of non-contrast and contrast-enhanced computed tomography in the diagnostic codes for urinary stone disease increased by 394.8% and 263.3% from 2009 to 2016, respectively (R²  = 0.83; R²  = 0.967). Conversely, the use of intravenous pyelography decreased 26.2% over the same period (R²  = 0.945).

CONCLUSIONS

Outpatient and inpatient procedures for urinary stone disease have increased over the past 8 years in Korea. Shock wave lithotripsy is the most widely used treatment modality for urinary stone disease, and endoscopic surgical procedures are rapidly being implemented. There has been a steep increase in the use of computed tomography, whereas conventional intravenous pyelography is declining.

In Vivo Differentiation of Uric Acid Versus Non-Uric Acid Urinary Calculi With Third-Generation Dual-Source Dual-Energy CT at Reduced Radiation Dose

OBJECTIVE

The objective of our study was to evaluate in vivo urinary calculus characterization with third-generation dual-source dual-energy CT (DECT) at reduced versus standard radiation dose.

SUBJECTS AND METHODS

One hundred fifty-three patients requiring unenhanced CT for suspected or known urolithiasis were prospectively included in our study. They underwent two acquisitions at reduced-dose CT (90 kV and 50 mAs_ref; Sn150 kV and 31 mAs_ref, where Sn denotes the interposition of a tin filter in the high-energy beam) and standard-dose CT (90 kV and 50 mAs_ref; Sn150 kV and 94 mAs_ref). One radiologist interpreted the reduced-dose examinations before the standard-dose examinations during the same session. Among 103 patients (23 women, 80 men; mean age ± SD, 50 ± 15 years; age range, 18-82 years) with urolithiasis, dedicated DECT software measured the maximal diameter and CT numbers, calculated the DECT number ratio, and labeled with a color code each calculus visualized by the radiologist as uric acid (UA) or non-UA. Volume CT dose index (CTDI_vol) and dose-length product (DLP) were recorded.

RESULTS

The radiologist visualized 279 calculi on standard-dose CT and 262 on reduced-dose CT; 17 calculi were missed on reduced-dose CT, all of which were ≤ 3 mm. Among the 262 calculi visualized at both doses, the CT number ratio was obtained with the software for 227 calculi and was not different between the doses (p = 0.093). Among these 262 calculi, 197 were labeled at both doses; 194 of the 197 labeled calculi were labeled with the same color code. Among the 65 remaining calculi, 48 and 61 (all ≤ 5 mm) were not labeled at standard-dose and reduced-dose CT (p = 0.005), respectively. At reduced-dose CT, the mean CTDI_vol was 2.67 mGy and the mean DLP was 102.2 mGy × cm.

CONCLUSION

With third-generation dual-source DECT, a larger proportion of calculi ≤ 5 mm are not characterized as UA or non-UA at a reduced dose.

Internal validation of a scoring system to evaluate the probability of ureteral stones: The CHOKAI score

OBJECTIVE

The CHOKAI and STONE scores are prediction models for ureteral stones. The aims of the present study were to evaluate the diagnostic performance, to examine the optimal cut-off value, and to compare the diagnostic performance of each model.

METHODS

Patients who presented to our emergency department with renal colic were considered for this prospective study. We analyzed the predictive performance of both STONE and CHOKAI scores at their optimal cut-off values, using receiver operating characteristic (ROC) curve and area under the curve (AUC), as well as sensitivity, specificity, positive likelihood ratio (LR+), and negative likelihood ratio (LR-) at the optimal cut-off value.

RESULTS

Of the 96 patients who met the inclusion criteria, 79 were definitively diagnosed with ureteral stones. All patients were of Japanese descent. The AUC of the CHOKAI score was 0.971 at an optimal cut-off value of 6, showing a sensitivity of 0.911, specificity of 0.941, LR+ of 15.49, and LR- of 0.094. The AUC of the STONE score was 0.873 at an optimal cut-off value of 8, showing a sensitivity of 0.823, specificity of 0.824, LR+ of 4.662, and LR- of 0.215. The AUC of the CHOKAI score was significantly higher than that of the STONE score (p=0.010). Of the 73 patients with a CHOKAI score of ≥6, 98.6% had ureteral stones, and of the 68 patients with a STONE score of ≥8, 95.6% had ureteral stones.

CONCLUSIONS

The simplified CHOKAI score is a useful tool to screen for ureteral stones in patients with renal colic.

Treatment selection for urolithiasis: percutaneous nephrolithomy, ureteroscopy, shock wave lithotripsy, and active monitoring

Urolithiasis is a significant worldwide source of morbidity, constituting a common urological disease that affects between 10 and 15% of the world population. Recent technological and surgical advances have replaced the need for open surgery with less invasive procedures. The factors which determine the indications for percutaneous nephrolithotomy include stone factors (stone size, stone composition, and stone location), patient factors (habitus and renal anomalies), and failure of other treatment modalities (ESWL and flexible ureteroscopy). The accepted indications for PCNL are stones larger than 20 mm², staghorn and partial staghorn calculi, and stones in patients with chronic kidney disease. The contraindications for PCNL include pregnancy, bleeding disorders, and uncontrolled urinary tract infections. Flexible ureteroscopy can be one of the options for lower pole stones between 1.5 and 2 cm in size. This option should be exercised in cases of difficult lower polar anatomy and ESWL-resistant stones. Flexible ureteroscopy can also be an option for stones located in the diverticular neck or a diverticulum. ESWL is the treatment to be discussed as a option in all patient with renal stones (excluding lower polar stones) between size 10 and 20 mm. In addition, in lower polar stones of size between 10 and 20 mm if the anatomy is favourable, ESWL is the option. In proximal ureteral stones, ESWL should be considered as a option with flexible ureteroscopy Active monitoring has a limited role and can be employed in post-intervention (PCNL or ESWL) residual stones, in addition, asymptomatic patients with no evidence of infection and fragments less than 4 mm can be monitored actively.

The Diagnosis and Management of Patients with Renal Colic across a Sample of US Hospitals: High CT Utilization Despite Low Rates of Admission and Inpatient Urologic Intervention

Objectives

Symptomatic ureterolithiasis (renal colic) is a common Emergency Department (ED) complaint. Variation in practice surrounding the diagnosis and management of suspected renal colic could have substantial implications for both quality and cost of care as well as patient radiation burden. Previous literature has suggested that CT scanning has increased with no improvements in outcome, owing at least partially to the spontaneous passage of kidney stones in the majority of patients. Concerns about the rising medical radiation burden in the US necessitate scrutiny of current practices and viable alternatives. Our objective was to use data from a diverse sample of US EDs to examine rates of and variation in the use of CT scanning, admission, and inpatient procedures for patients with renal colic and analyze the influence of patient and hospital factors on the diagnostic testing and treatment patterns for patients with suspected renal colic.

Methods

We conducted a retrospective cohort study of adult patients who received a diagnosis of renal colic via a visit to an ED at 444 US hospitals participating in the Premier Healthcare Alliance database from 2009–2011. We modeled use of CT, admission, and inpatient urologic intervention as functions of both patient characteristics and hospital characteristics.

Results

Over the 2-year period, 307,612 patient visits met inclusion criteria. Among these patients, 254,211 (82.6%) had an abdominal CT scan, with 91.5% being non-contrast (“renal protocol”) CT scans. Nineteen percent of visits (58,266) resulted in admission or transfer, and 9.8% of visits (30,239) resulted in a urologic procedure as part of the index visit. On multivariable analysis male patients, Hispanic patients, uninsured patients, and privately insured patients were more likely to have a CT scan performed. Older patients and those covered by Medicare were more likely to be admitted, and once admitted, white patients and privately insured patients were more likely to have a urologic intervention. Only hospital region was associated with variation in CT rates, and this variation was minimal. Region and size of the hospital were associated with admission rates, and hospitals with more practicing urologists had higher intervention rates.

Conclusions

In this dataset, the majority of patients did not require admission or immediate intervention. Despite this, the large majority received CT scans, in a cohort representing 15–20% of all US ED visits. The CT rate was minimally variable at the hospital level, but the admission rates varied 2-fold, suggesting that hospital-level factors affect patient management. The high rate of CT usage coupled with the low rate of immediate intervention suggests that further research is warranted to identify patients who are at low risk for an immediate intervention, and could potentially be managed with ultrasound alone, expectant management, or delayed CT.