The utility of renal ultrasonography in the diagnosis of renal colic in emergency department patients

Incidental detection of malignancy on point-of-care renal ultrasound: A case series

Renal point-of-care ultrasound (POCUS) is an increasingly common initial imaging modality in the diagnostic workup of renal colic. The primary use of renal POCUS is to assess for hydronephrosis; however, other significant findings suggestive of malignancy can also be identified. We present three cases of unexpected findings identified initially on POCUS in the emergency department, which subsequently led to new diagnoses of malignancy. As renal POCUS becomes more frequently used in clinical practice, physicians must be able to recognise abnormal images that indicate possible malignancy and the need for further workup.

Application of deep learning reconstruction of ultra-low-dose abdominal CT in the diagnosis of renal calculi

BACKGROUND

Renal calculi are a common and recurrent urological disease and are usually detected by CT. In this study, we evaluated the diagnostic capability, image quality, and radiation dose of abdominal ultra-low-dose CT (ULDCT) with deep learning reconstruction (DLR) for detecting renal calculi.

METHODS

Sixty patients with suspected renal calculi were prospectively enrolled. Low-dose CT (LDCT) images were reconstructed with hybrid iterative reconstruction (LD-HIR) and was regarded as the standard for stone and lesion detection. ULDCT images were reconstructed with HIR (ULD-HIR) and DLR (ULD-DLR). We then compared stone detection rate, abdominal lesion detection rate, image quality and radiation dose between LDCT and ULDCT.

RESULTS

A total of 130 calculi were observed on LD-HIR images. Stone detection rates of ULD-HIR and ULD-DLR images were 93.1% (121/130) and 95.4% (124/130). A total of 129 lesions were detected on the LD-HIR images. The lesion detection rate on ULD-DLR images was 92.2%, with 10 cysts < 5 mm in diameter missed. The CT values of organs on ULD-DLR were similar to those on LD-HIR and lower than those on ULD-HIR. Signal-to-noise ratio was highest and noise lowest on ULD-DLR. The subjective image quality of ULD-DLR was similar to that of LD-HIR and better than that of ULD-HIR. The effective radiation dose of ULDCT (0.64 ± 0.17 mSv) was 77% lower than that of LDCT (2.75 ± 0.50 mSv).

CONCLUSION

ULDCT combined with DLR could significantly reduce radiation dose while maintaining suitable image quality and stone detection rate in the diagnosis of renal calculi.

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.

Pearl-unjammed: the Seattle stone maneuver for ureteropelvic junction urolithiasis

Renal colic encounters are common; in the United States alone, they represent greater than one million annual emergency department (ED) visits. Most of these stones are managed conservatively with a trial of passage. However, some lead to repeat colic episodes, secondary ED visits, increased anxiety, and increased cost. Of the 5%-10% of symptomatic stones that become lodged at the ureteropelvic junction and are larger than 5 mm, most require operative intervention. In the process of executing a NASA-funded study of ultrasonic repositioning of kidney stones, the subject was administered fluid to dilate the collecting system, placed in Trendelenburg bed positioning, and rolled to both sides. During this process a symptomatic, obstructing 9-mm ureteropelvic junction stone moved back into the kidney's lower pole/infundibulum and symptoms were immediately resolved. The patient remained asymptomatic for a period of 5 weeks at which point elective intervention was scheduled. This case demonstrates that ureteropelvic junction stones may be repositioned in a non-invasive manner, turning a stone that requires urgent intervention into one that can be managed electively.

Point-of-care ultrasound for the detection of hydronephrosis in emergency department patients with suspected renal colic

Background

Point-of-care ultrasound (PoCUS) by emergency physicians for renal colic has been proposed as an alternative to computed tomography (CT) to avoid ionizing radiation exposure and shorten emergency department length of stay. Previous studies have employed experienced or credentialed ultrasonographers or required advanced ultrasound skills. We sought to measure the diagnostic accuracy of PoCUS by physicians with varied experience using a simplified binary outcome of presence or absence of hydronephrosis. Secondary outcomes include assessment as to whether the presence of hydronephrosis on PoCUS is predictive of complications, and to evaluate possible causes for the reduced diagnostic accuracy such as body mass index (BMI) and time between PoCUS and formal imaging, and scanner experience.

Results

413 patients were enrolled in the study. PoCUS showed a specificity of 71.8% [95% CI 65.0, 77.9] and sensitivity of 77.1% [95% CI 70.9, 82.6]. Hydronephrosis on PoCUS was predictive of complications (relative risk 3.13; [95% CI 1.30, 7.53]). The time interval between PoCUS and formal imaging, BMI, and scanner experience did not influence the accuracy of PoCUS.

Conclusions

PoCUS for hydronephrosis in suspected renal colic has moderate accuracy when performed by providers with varied experience for the binary outcome of presence or absence of hydronephrosis. Hydronephrosis on PoCUS is associated with increased rates of complications. PoCUS for hydronephrosis is limited in its utility as a stand-alone test, however this inexpensive, readily available test may be useful in conjunction with clinical course to determine which patients would benefit from formal imaging or urologic consultation.

ClinicalTrials.gov Identifier NCT01323842

Imaging Modalities in Genitourinary Emergencies

Emergency physicians rely on a multitude of different imaging modalities in the diagnosis of genitourinary emergencies. There are many considerations to be taken into account when deciding which imaging modality should be used first, as oftentimes several diagnostic tools can be used for the same pathologic condition. These factors include radiation exposure, sensitivity, specificity, age of patient, availability of resources, cost, and timeliness of completion. In this review, the strengths and weaknesses of different imaging tools in the evaluation of genitourinary emergencies are discussed.

Renal Colic Imaging: Myths, Recent Trends, and Controversies

There has been a substantial increase in the utilization of imaging, particularly of multi-detector computed tomography (MDCT), for the evaluation of patients with suspected urolithiasis over the past 2 decades. While the diagnostic accuracy of computed tomography (CT) for urolithiasis is excellent, it has also resulted in substantial medical expenditures and increased ionizing radiation exposure. This is especially concerning in patients with known nephrolithiasis and in younger patients. This pictorial review will focus on recent trends and controversies in imaging of patients with suspected urolithiasis, including the current roles of ultrasound (US), MDCT, and magnetic resonance imaging, the estimated radiation dose from MDCT and dose reduction strategies, as well as imaging of suspected renal colic in pregnant patients. The current epidemiological, clinical, and practice management literature will be appraised.

Evaluation of the clinical significance of sonographic perinephric fluid in patients with renal colic

OBJECTIVE

To evaluate the significance of sonographic perinephric fluid collection on the emergent management of patients with acute urinary stone obstruction.

METHODS

We conducted a prospective study with retrospective analysis. Since January 2016 through July 2017, patients admitted to our tertiary hospital's emergency department (ED) with suspected symptomatic urinary stones underwent ultrasound evaluation. Images were prospectively interpreted by experienced radiologist who analyzed each case for the following imaging features: hydronephrosis, perinephric fluid and urethral stone identification. The presence and measurements of perinephric fluid were re-evaluated by second radiologist who was blinded for the first reader's measurements. Retrospective analysis was conducted to evaluate for an association between perinephric fluid collection and the following outcome variables: need for analgesics, the number of doses of analgesics and the amount of morphine (mg) in the ED, elevation of creatinine levels, hospitalization and need for urological interventions.

RESULTS

The need for analgesics, the number of doses of analgesics and the amount of morphine were significantly associated with the presence of perinephric fluid (p < 0.05). The odds ratio for the need for analgesics was 3.8 in the presence of any perinephric fluid, and 8.9 in the presence of moderate/severe perinephric fluid. No other patient outcome variables were found to be significantly associated with the presence of perinephric fluid (p > 0.05).

CONCLUSIONS

This study shows a correlation between sonographic evidence of perinephric fluid and more severe pain. Therefore, an emergency physician can consider the evidence of perinephric fluid, in acute urethral stone obstruction, a predictor for more severe pain.

Clinical predictors of an abnormal ultrasound in patients presenting with suspected nephrolithiasis

Objective:

To determine any clinical features associated with an abnormal ultrasound in patients with suspected nephrolithiasis in an out-patient setting.

Methods:

The study design was cross-sectional in nature. The study was conducted at an out-patient nephrology department of a tertiary care facility over a 3 month period. Patients included in the study were 18-80 years old, who presented with unilateral flank or costovertebral angle pain with or without other clinical features suggestive of renal or ureteric calculus based on clinician’s judgement. Every patient’s history was reviewed to obtain information on age, gender, location and radiation of pain, onset, severity and nature of pain, associated urinary and systemic symptoms and past history of nephrolithiasis. An ultrasound was considered to be abnormal if there was documented presence of renal or ureteric stone and/or unilateral hydronephrosis.

Results:

A total of 209 patients were included in the study. Of these patients, 126 (60.3%) were males and 83 (39.7%) were females, 60 (28.7%) had prior history of nephrolithiasis. Ultrasound was abnormal in 110 patients (52.9%). On a multivariate logistic regression analysis, only past history of nephrolithiasis (OR 3.3, 95% CI 1.65-6.7) was associated with an abnormal ultrasound.

Conclusion:

In the absence of any significant clinical predictors use of ultrasound is justified in patients with suspected nephrolithiasis especially in those with prior history of stones.

My patient has abdominal and flank pain: Identifying renal causes

Acute flank and abdominal pain are common presenting complaints in the emergency department. With increasing access to point-of-care ultrasound (PoCUS), emergency physicians have an added tool to help identify renal problems as a cause of a patient's pain. PoCUS for hydronephrosis has a sensitivity of 72-83.3% and a varying specificity, similar to radiology-performed ultrasonography. In addition to assessment for hydronephrosis, PoCUS can help emergency physicians to exclude other serious causes of flank and abdominal pain such as the presence of an abdominal aortic aneurysm, or free fluid in the intraperitoneal space, which could represent hemorrhage. Use of PoCUS for the assessment of flank pain has resulted in more rapid diagnosis, decreased use of computed tomography, and shorter emergency department length of stay.

Clinician-performed abdominal sonography

INTRODUCTION

Point-of-care ultrasonography is increasingly utilized across a wide variety of physician specialties. This imaging modality can be used to evaluate patients rapidly and accurately for a wide variety of pathologic conditions.

METHODS

A literature search was performed for articles focused on clinician-performed ultrasonography for the diagnosis of appendicitis, gallbladder disease, small bowel obstruction, intussusception, and several types of renal pathology. The findings of this search were summarized including the imaging techniques utilized in these studies.

CONCLUSION

Clinician performed point-of-care sonography is particularly well suited to abdominal applications. Future investigations may further confirm and extend its utility at the bedside.

Familiarity with radiation exposure dose from diagnostic imaging for acute pulmonary embolism and current patterns of practice

OBJECTIVE

To assess the current level of knowledge and practice patterns of emergency physicians regarding radiation exposure from diagnostic imaging modalities for investigating acute pulmonary embolism (PE).

METHODS

An online survey was sent to adult emergency physicians working at two academic tertiary care adult emergency departments (EDs) to determine imaging choices for investigating PE in various patient populations and to assess their current knowledge of radiation doses and risks. A retrospective chart review was performed for all adult patients who underwent computed tomographic pulmonary angiography (CTPA) and/or ventilation-perfusion (V/Q) scanning in the same EDs.

RESULTS

The survey response rate was 72.1% (31 of 43 physicians). For patients < 30 years old, 83.9% of physicians chose V/Q scanning as their test of choice, regardless of gender. Although only a third of respondents knew the estimated radiation dose of a V/Q scan (37.5%) and a CTPA (32%), the majority were aware that V/Q scans involved less ionizing radiation than CTPAs. In the retrospective review, 663 charts were reviewed, including 201 CTPAs and 462 V/Q scans. V/Q scanning was the preferred modality in female patients (75.9% v. CTPA 24.1% [OR 2.1; 95% CI 1.5-2.9]) and in patients < 30 years old (87.9% v. CTPA 12.1% [OR 4.8; 95% CI 2.4-9.4]).

CONCLUSIONS

Although surveyed physicians possessed limited knowledge of radiation doses of CTPA and V/Q scans, they preferentially used the lower radiation V/Q scans in younger patients, particularly females, in both the survey vignettes and in clinical practice. This may reflect efforts to reduce radiation exposures at our institution.

Ultrasonography versus computed tomography for suspected nephrolithiasis

BACKGROUND

There is a lack of consensus about whether the initial imaging method for patients with suspected nephrolithiasis should be computed tomography (CT) or ultrasonography.

METHODS

In this multicenter, pragmatic, comparative effectiveness trial, we randomly assigned patients 18 to 76 years of age who presented to the emergency department with suspected nephrolithiasis to undergo initial diagnostic ultrasonography performed by an emergency physician (point-of-care ultrasonography), ultrasonography performed by a radiologist (radiology ultrasonography), or abdominal CT. Subsequent management, including additional imaging, was at the discretion of the physician. We compared the three groups with respect to the 30-day incidence of high-risk diagnoses with complications that could be related to missed or delayed diagnosis and the 6-month cumulative radiation exposure. Secondary outcomes were serious adverse events, related serious adverse events (deemed attributable to study participation), pain (assessed on an 11-point visual-analogue scale, with higher scores indicating more severe pain), return emergency department visits, hospitalizations, and diagnostic accuracy.

RESULTS

A total of 2759 patients underwent randomization: 908 to point-of-care ultrasonography, 893 to radiology ultrasonography, and 958 to CT. The incidence of high-risk diagnoses with complications in the first 30 days was low (0.4%) and did not vary according to imaging method. The mean 6-month cumulative radiation exposure was significantly lower in the ultrasonography groups than in the CT group (P<0.001). Serious adverse events occurred in 12.4% of the patients assigned to point-of-care ultrasonography, 10.8% of those assigned to radiology ultrasonography, and 11.2% of those assigned to CT (P=0.50). Related adverse events were infrequent (incidence, 0.4%) and similar across groups. By 7 days, the average pain score was 2.0 in each group (P=0.84). Return emergency department visits, hospitalizations, and diagnostic accuracy did not differ significantly among the groups.

CONCLUSIONS

Initial ultrasonography was associated with lower cumulative radiation exposure than initial CT, without significant differences in high-risk diagnoses with complications, serious adverse events, pain scores, return emergency department visits, or hospitalizations. (Funded by the Agency for Healthcare Research and Quality.).

The renal resistive index as a predictor of acute hydronephrosis in patients with renal colic

INTRODUCTION

The objective of this study was to determine whether the renal resistive index (RI) can predict hydronephrosis in patients with renal colic (RC) and whether or not its performance is time-dependent.

MATERIALS AND METHODS

The study population was composed of 54 patients admitted for unilateral RC. At the time of the first observation (time point I, tpI), each patient underwent routine examinations, abdominal ultrasonography, and renal color Doppler ultrasound (CDUS) with measurement of the RI. The two imaging studies were repeated 6, 12, 18, 24, 36, and 48 h later (tpII, tpIII, tpIV, tpV, tpVI, tpVII). In addition, each patient underwent non-contrast urinary tract CT 48-60 h after admission. A mean renal RI of >0.70 (mRI+) for the symptomatic kidney was considered indicative of obstruction. Patients were retrospectively divided into two groups: those who developed dilatation (group A) and those who did not (group B).

RESULTS

A mRI+ on CDUS predicted the onset of hydronephrosis with 100% sensitivity, 84% specificity, 92.6% accuracy, PPV and NPV of 87.9% and 100%, and diagnostic efficiency of 84%. In group A, mRI+ were always observed before onset of hydronephrosis in a time-dependent manner. In group B, mRI+ were observed occasionally in 4/25 patients (16%) and all were recorded at tpII. In these cases, the RI had returned to normal by tpIII.

CONCLUSIONS

In our RC patients, renal RI obtained with CDUS predicted the onset of acute dilatation with higher sensitivity, specificity, accuracy, and diagnostic efficiency than ultrasonography, and it can be used routinely in the emergency department to supplement ultrasound findings.

National trends in use of computed tomography in the emergency department

STUDY OBJECTIVE

The role of computed tomography (CT) in acute illnesses has increased substantially in recent years; however, little is known about how CT use in the emergency department (ED) has changed over time.

METHODS

A retrospective study was performed with the 1996 to 2007 National Hospital Ambulatory Medical Care Survey, a large nationwide survey of ED services. We assessed changes during this period in CT use during an ED visit, CT use for specific ED presenting complaints, and disposition after CT use. Main outcomes were presented as adjusted risk ratios (RRs).

RESULTS

Data from 368,680 patient visits during the 12-year period yielded results for an estimated 1.29 billion weighted ED encounters, among which an estimated 97.1 million (7.5%) patients received at least one CT. Overall, CT use during ED visits increased 330%, from 3.2% of encounters (95% confidence interval [CI] 2.9% to 3.6%) in 1996 to 13.9% (95% CI 12.8% to 14.9%) in 2007. Among the 20 most common complaints presenting to the ED, there was universal increase in CT use. Rates of growth were highest for abdominal pain (adjusted RR comparing 2007 to 1996=9.97; 95% CI 7.47 to 12.02), flank pain (adjusted RR 9.24; 95% CI 6.22 to 11.51), chest pain (adjusted RR 5.54; 95% CI 3.75 to 7.53), and shortness of breath (adjusted RR 5.28; 95% CI 2.76 to 8.34). In multivariable modeling, the likelihood of admission or transfer after a CT scan decreased over the years but has leveled off more recently (adjusted RR comparing admission or transfer after CT in 2007 to 1996=0.42; 95% CI 0.32 to 0.55).

CONCLUSION

CT use in the ED has increased significantly in recent years across a broad range of presenting complaints. The increase has been associated with a decline in admissions or transfers after CT use, although this effect has stabilized more recently.