Is the KUB radiograph redundant for investigating acute ureteric colic in the non-contrast enhanced computed tomography era?

[Imaging in nephroureterolithasis]

In the acute diagnostics of a suspected nephroureterolithiasis, ultrasonography should be the examination modality of choice. In cases of suspected urolithiasis, unclear flank pain with fever or in cases of a solitary kidney, a noncontrast computed tomography (CT) scan should always subsequently be performed. If the sonography findings are inconclusive in pregnant women a magnetic resonance imaging (MRI) examination can be considered. If there are indications for urinary diversion, a retrograde imaging study should be performed as part of the urinary diversion. This or CT imaging is also suitable for preinterventional imaging before shock wave lithotripsy, percutaneous nephrolithotomy or ureteroscopy. Postinterventional imaging is not always necessary and sonography is often sufficient. In a conservative treatment approach an abdominal plain X‑ray can be used for follow-up assessment.

2022 Recommendations of the AFU Lithiasis Committee: Diagnosis

The choice of imaging modality is guided by the clinical presentation and the context (acute or not). Although ultrasound is safe (no radiation) and easily available, non-contrast-enhanced CT has become the gold standard in the diagnostic strategy for patients with acute flank pain because of its sensitivity (93.1%) and specificity (96.6%). It also allows determining the stone size, volume and density, visualizing their internal structure, and assessing their distance from the skin and the adjacent anatomy. All these parameters can influence the stone management and the choice of intervention modality. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations method (CPR) and the ADAPTE method, depending on whether the issue was considered in the EAU recommendations (https://uroweb.org/guidelines/urolithiasis [EAU Guidelines on urolithiasis. 2022]) and their adaptability to the French context.

Evaluation, management, and analysis of demographic and radiological characteristics of patients with renal colic at a tertiary hospital in Somalia

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Renal Colic is a common emergenbcy care complaint worldwide–but its epidemiology and strategies for evaluation and treatment have been little reported in Africa.

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To date, there have been no studies regarding epidemiologic and radiological findings of renal colic in the emergency centre reported from Somalia.

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Ultrasound can be the initial investigation of choice because it is safe, cheap, and may help guide for diagnosis and need for further imaging.

Background

Renal colic is a common emergency centre (EC) complaint worldwide, but its epidemiology and strategies for evaluation and treatment have been little reported in Africa. To the best of our knowledge, this is the first study aimed at evaluating the radiological investigations, management, and analysis of demographic characteristics of patients with urinary system stones who visited the EC.

Method

A 3-year retrospective study of a total of 435 patients with acute renal colic who underwent radiologic investigations was included in this study. The overall positive stone rate, stone location, size, and hydronephrosis grade were assessed. The sensitivity and specificity of ultrasound were evaluated using patients with both an ultrasound and a non-contrast CT (NCCT).

Results

The mean age of the patients was 34.7years; males accounted for 71.3% (n = 310), while females were 28.7% (n = 125). Urolithiasis was found in 63.4% of the cases, 71.3% of males and 28.7% of the females had a stone diagnosis (P < 0001). There was no statistically significant association between age and stone diagnosis (P > 0.05). The sensitivity and specificity of USG were 86.1% and 94%, respectively. Seventy-two percent of the cases had ureteral stones (29% in proximal, 25% in UVJ, 9% in mid, and 9% in distal ureter), followed by 28% having renal stones (19% calyces and 9% in renal pelvis). The mean size of the stone was 5.9±1.8, half of the cases harbour stone size <5mm, followed by 30% in 5mm-1cm.

Conclusion

Due to the scarcity of well-equipped tertiary care hospitals and the low socioeconomic status of the patients living in Sub-Saharan Africa, Ultrasound can be the initial investigation of choice because it is safe, cheap, and may help guide diagnosis and the need for further imaging. However, NCCT remains the gold standard diagnosis of choice for acute flank pain.

[Follow-up after urolithiasis management]

BACKGROUND

Urinary stones often affect younger people. Because the risk of recurrence is high, regular follow-up is important for individuals at risk.

OBJECTIVE

To summarize the extent of urinary stones and the health and economic impact in the population; to provide recommendations for general and stone-specific follow-up.

MATERIALS AND METHODS

Analysis and discussion of publications and guideline recommendations.

RESULTS

The risk of recurrence after a stone attack can be high depending on the risk profile. An initial metabolic workup should be performed promptly after stone therapy. General dietary management should be intensified by stone-specific dietary management depending on the risk profile. Nutritional counseling may be helpful. Imaging after stone therapy is used to monitor the success of treatment and detect recurrences early. Since the risk of recurrence can vary greatly depending on the stone composition, not only the type of imaging but also its frequency should be adjusted accordingly. The same applies to the various stone therapies, which help determine the frequency and type of imaging follow-up. Exact guidelines and cost-effectiveness analyses of follow-up examinations after stone therapy are unfortunately missing.

CONCLUSIONS

Acute urolithiasis represents an excruciating experience for patients. Accordingly, their willingness to undergo metaphylaxis and follow-up shortly after the event is strong. Since the risk of recurrence after a stone attack can be very high, regular follow-up after stone therapy is essential. The frequency of follow-up should be adapted to the probability of stone recurrence.

Is Combined Ultrasound with Radiography Sufficient for the Diagnosis of Obstructive Ureteric Stone in Patients with Acute Flank Pain?

Context

Ultrasound (US) is excellent for detection of hydronephrosis but has poor sensitivity for stone detection. In contrast, radiography of the kidney-ureter-bladder has better sensitivity for detection of stone but limited sensitivity for hydronephrosis detection. A combination of these two modalities may improve both sensitivity and specificity for the diagnosis of obstructive ureteric stone.

Aims

This study aims to investigate the diagnostic accuracy of combined US with radiography for the diagnosis of obstructive ureteric stone in adult patients.

Settings and Design

Retrospective study with retrospective data collection performed in a 1500-bed university hospital.

Materials and Methods

A total of 90 patients were included. The electronic medical record, radiological reports, laboratory results, and patient management were extracted and analyzed.

Statistical Analysis Used

The diagnostic performance of US, radiography, and combined US with radiography were calculated and compared. The computed tomography was used as diagnostic reference.

Results

US alone had a sensitivity of 73.5%, specificity of 92.7%, and negative predictive value (NPV) of 74.5% for hydronephrosis. When US showed both ureteric stone and hydronephrosis, sensitivity dropped to 14.3% but specificity increased to 100%. Radiography alone had a sensitivity of 34.7%, specificity of 100%, and NPV of 56.2% for the detection of ureteric stone. Combining radiography with US raised the sensitivity for diagnosis of obstructive ureteric stone to 88% with a specificity of 93% and accuracy of 90%.

Conclusions

Combined US with radiography was accurate for the diagnosis of obstructive ureteric stone in patients presenting with acute flank pain.

Minimally invasive management of acute ureteral obstruction and severe infection caused by upper urinary tract calculi

PURPOSETo evaluate therapeutic efficacy of two minimally invasive surgical methods in managing acute ureteral obstruction and severe infection caused by upper urinary tract calculi (UUTC).PATIENTS AND METHODSData of 47 patients diagnosed with acute upper urinary tract obstruction and severe infection caused by ureteral calculus using X-ray CT between September 2014 and January 2019 were retrospectively analyzed. All patients were treated with immediate renal drainage and, after infection and ureteral obstruction were relieved, UUTC removal. Renal drainage was performed by ultrasound-guided percutaneous nephrostomy and retrograde ureteral catheterization was performed using cystoscopy. Kidney and ureteral stones were removed; renal function and the urinary tract were examined by X-ray during follow-up.RESULTSPercutaneous nephrostomy was performed in 29 patients in a critical condition including intolerance to surgery, high-grade hydronephrosis, or failure of retrograde ureteric stent placement. In other 18 patients diagnosed with small stones (≤10 mm) and low-grade hydronephrosis, indwelling double-J ureteral stents were temporally installed by a cystoscope. Acute infection and ureteral obstruction were relieved; white blood cell counts returned to normal values within 3 to 7 days after drainage in all patients. In the second-stage treatment, percutaneous nephrolithotomy (PCNL), ureteroscopic lithotripsy, extracorporeal shock wave lithotripsy and nephrectomy were performed in 24, 10, 8 and 5 patients, respectively. No patients developed severe complication after stone removal surgery. All patients were followed up for 3 months to 4.5 years. Renal function was significantly recovered; 17/29 (59%) patients with elevated serum creatinine returned to normal and serum creatinine in 12/29 (41%) patients improved significantly after drainage, with a pre-operation level of 285±169μM vs 203±91μM post-operation (P = 0.014). Five patients were lost during follow-up.CONCLUSIONThis study demonstrated an optimal approach for relieving upper urinary tract obstruction and acute infection in which percutaneous nephrostomy drainage is preferred for patients with severe pyonephrosis, large stones (>10 mm) with high-grade hydronephrosis, steinstrasse, or failure in retrograde ureteric stent placement, while retrograde ureteral catheterization using cystoscopy is suitable for patients diagnosed with small stones (≤10 mm) and low-grade hydronephrosis.

Identification of ureteral stones at reduced radiation exposure: a pilot study comparing conventional versus digital low-dosage linear slot scanning (Lodox®) radiography

PURPOSE

Digital low-dosage, linear slot scanning radiography (Lodox^®) is an imaging modality that can emit down to one-tenth the radiation of conventional X-ray systems. We prospectively evaluated Lodox^® as a diagnostic imaging modality in patients with ureterolithiasis.

METHODS

Conventional kidney-ureter-bladder (KUB) X-ray and Lodox^® were performed in 41 patients presenting with acute flank pain due to unilateral ureteral stone confirmed by computed tomography. KUB X-ray and Lodox^® images were then reviewed by four blinded readers (urology expert/resident, radiology expert/resident). Identification rates were compared using Pearson's Chi square test. The impact of different parameters on stone identification by Lodox^® was evaluated using logistic regression and generalized linear mixed models. Inter-reader agreement was tested using Cohen's kappa coefficient.

RESULTS

Median stone size was 5 mm (range 2-12), median stone density was 800 HU (range 200-1500). The identification rates of the urology expert were 68% for KUB X-ray and 90% for Lodox^® (p = 0.014), and for all four readers 61% for KUB X-ray and 62% for Lodox^® (p = 0.8). Radiation exposure for KUB X-ray and Lodox^® was 0.45 mSv (SD ± 0.64) and 0.027 mSv (SD ± 0.038), respectively. Multivariable analyses showed an association between stone identification by Lodox^® and stone size (p < 0.001), stone density (p = 0.005), lower body mass index (p = 0.005), and reader (p < 0.001).

CONCLUSIONS

The high identification rates and low radiation doses of Lodox^® make it a promising imaging modality for the diagnosis of ureteral stones. Further validation in larger cohorts, including performance evaluation for renal stones, is warranted.

TRIAL REGISTRATION

http://www.controlled-trails.com/ISRCTN12915426.

High-pitch low-dose abdominopelvic CT with tin-filtration technique for detecting urinary stones

OBJECTIVES

To evaluate urinary stone detection, radiation exposure, image quality, breathing-motion artifacts, and scanning time with high-pitch tin filter-based abdominopelvic CT.

METHODS

Sixty-three consecutive patients with urolithiasis underwent non-enhanced abdominopelvic CT with both regular (120 kV, pitch 0.6) and low-dose (Sn150kV, pitch 3.0) protocols on a third-generation dual-source CT. Stone characteristics, image noise (SD), signal-to-noise ratio (SNR), subjective image quality on a 5-point likert scale breathing-motion artifacts, and scanning time were evaluated. Volume CT dose index (CTDIvol), dose-length product (DLP), effective dose (ED) were compared.

RESULTS

A total of 157 urinary stones were detected by regular protocol; 154 were correctly identified by low-dose protocol with an overall detection rate of 98.1%. No significant differences were observed in SD, SNR, or subjective image quality between two protocols (P > 0.05). Compared to regular protocol, CTDIvol and ED were 56.6% (7.19 vs. 3.12 mGy, P < 0.001) and 55.6% (5.25 vs. 2.33 mSv, P < 0.001) lower; scanning time was 89.5% (7.9 vs. 0.83, P < 0.001) shorter; and breathing-motion artifacts were fewer (8 vs. 0 patients) with low-dose protocol.

CONCLUSIONS

High-pitch abdominopelvic CT with Sn150kV substantially reduced radiation exposure and scanning time, while maintained stone detection and image quality and prevented breathing-motion artifacts.

Low-dose abdominal computed tomography for detection of urinary stone disease - Impact of additional spectral shaping of the X-ray beam on image quality and dose parameters

OBJECTIVES

To evaluate a novel tin filter-based abdominal CT protocol for urolithiasis in terms of image quality and CT dose parameters.

METHODS

130 consecutive patients with suspected urolithiasis underwent non-enhanced CT with three different protocols: 48 patients (group 1) were examined at tin-filtered 150kV (150kV Sn) on a third-generation dual-source-CT, 33 patients were examined with automated kV-selection (110-140kV) based on the scout view on the same CT-device (group 2), and 49 patients were examined on a second-generation dual-source-CT (group 3) with automated kV-selection (100-140kV). Automated exposure control was active in all groups. Image quality was subjectively evaluated on a 5-point-likert-scale by two radiologists and interobserver agreement as well as signal-to-noise-ratio (SNR) was calculated. Dose-length-product (DLP) and volume CT dose index (CTDIvol) were compared.

RESULTS

Image quality was rated in favour for the tin filter protocol with excellent interobserver agreement (ICC=0.86-0.91) and the difference reached statistical significance (p<0.001). SNR was significantly higher in group 1 and 2 compared to second-generation DSCT (p<0.001). On third-generation dual-source CT, there was no significant difference in SNR between the 150kV Sn and the automated kV selection protocol (p=0.5). The DLP of group 1 was 23% and 21% (p<0.002) lower in comparison to group 2 and 3, respectively. So was the CTDIvol of group 1 compared to group 2 (-36%) and 3 (-32%) (p<0.001).

CONCLUSION

Additional shaping of a 150kV source spectrum by a tin filter substantially lowers patient exposure while improving image quality on un-enhanced abdominal computed tomography for urinary stone disease.

Urolithiasis--an interdisciplinary diagnostic, therapeutic and secondary preventive challenge

BACKGROUND

The prevalence of urolithiasis in Germany is 4.7%; its incidence has trebled in the last three decades. The risk of recurrence is 50-80%, depending on the type of stone, unless secondary prevention is instituted. Risk-adapted secondary prevention lowers this risk to 10-15%.

METHODS

This review is based on publications retrieved by a selective search in PubMed using the key words "urolithiasis," "urinary stones," "epidemiology," "lithogenesis," "biominerals," "risk factors," and "diagnosis, therapy, metaphylaxis." These publications were evaluated with the aid of the urolithiasis guideline of the European Association of Urology.

RESULTS

Acute renal colic can usually be diagnosed without sophisticated equipment. Stones can be dealt with by a variety of techniques depending on their size and location, including extracorporeal shock-wave lithotripsy, ureterorenoscopy, percutaneous nephrolitholapaxy, and open surgery. Most ureteric stones of diameter up to 5 mm pass spontaneously. 75% of patients have no complications. The basic evaluation needed for secondary prevention can be carried out by any physician on an ambulatory basis. In the 25% of patients who have complications, a more extensive interdisciplinary evaluation of metabolic parameters should be performed in a clinical center for urinary stones.

CONCLUSION

Urolithiasis has many causes and can be treated in many different ways. An extensive metabolic work-up is often necessary for secondary prevention. The various treatment options must be considered for their suitability in each individual patient. Robust data are now available on surgical and interventional methods, but there are as yet no high-quality trials of secondary prevention. Further research should concentrate on the etiology and pathogenesis of urolithiasis.

Do we really need kidneys-ureters-bladder radiography to predict stone radiopacity before treatment with shockwave lithotripsy? Development and internal validation of a novel predictive model based on computed tomography parameters

PURPOSE

To produce and validate a predictive model based on CT parameters for calculating the probability of a stone to be visible on fluoroscopy of shockwave lithotripsy (SWL) and to compare its accuracy to that of kidneys-ureters-bladder (KUB) radiography.

METHODS

We retrospectively analyzed 306 patients (sample group) who underwent an SWL between March 2011 and August 2012. A multivariate analysis of several parameters extracted from the preoperative CT scan was conducted to identify independent predictors for radiopacity on SWL fluoroscopy. The results were used for the creation of a predictive model. Internal validation was made on a group of 75 patients (validation group) treated from September 2012 until December 2012. Predictive accuracy of the model was evaluated by receiver operating characteristic (ROC) curve and calibration plot. The ROC curve was also used for comparing the predictive accuracy of the model to that of KUB radiography.

RESULTS

From 306 evaluated stones, 238 (77.8%) were visible on fluoroscopy. Results of the multivariate analysis revealed that stone size (P<0.001), stone attenuation (P<0.001), location in the midureter (P<0.001), the distance between the stone and the anterior abdominal wall (P<0.001), and fat thickness of the anterior abdominal wall (P=0.001) were all independent predictors for stone radiopacity on fluoroscopy. A predictive model was produced based on the above parameters. The model demonstrated high calibration and areas under the curve of 0.923 and 0.965 in the sample and validation group, respectively, while its predictive performance was significantly higher (P<0.001) of that of KUB radiography (area under the curve=0.727).

CONCLUSIONS

This novel model can estimate with high accuracy stone radiopacity on SWL fluoroscopy using parameters of CT scan and thus it can be used as an alternative to KUB radiography for treatment planning.

Imaging for Urinary Stones: Update in 2015

CONTEXT

Imaging is essential for the diagnosis and the clinical decision-making process of patients with urinary stones.

OBJECTIVE

To assess the benefits and limitations of various imaging techniques by specifically focusing on different phases of stone patients' management.

EVIDENCE ACQUISITION

PubMed and Web of Science databases were used to identify studies published in the last 10 yr on this argument. Search terms included 'urolithiasis', nephrolithiasis', or 'urinary stones' in combination (AND) with the terms 'imaging', 'computer tomography', 'ultrasonography', 'intravenous pyelogram', or 'radiation exposure'. Study selection was based on an independent peer-review process of all the authors after the structured data search.

EVIDENCE SYNTHESIS

Noncontrast-enhanced computer tomography (CT) provides the highest value of diagnostic accuracy for urinary stones. Stone composition can be specifically assessed through the use of dual-energy CT. When information about the anatomy of the renal collecting system is required or alternative pathologies are suspected, CT with contrast injection is recommended. Low-dose protocols allowed a drastic reduction of the effective dose administered to the patient, thus limiting the biological risk due to ionising radiations. Other strategies to contain the radiation exposure include the dual-split bolus dual energy CT and the adaptive statistical image reconstruction. Abdomen ultrasound may be a valid alternative as an initial approach since it does not change the outcome of patients compared with CT, and should be the imaging of choice in children and pregnant women.

CONCLUSIONS

Noncontrast-enhanced CT is the most accurate imaging technique to identify urinary stones. Abdomen ultrasound seems to be a valid alternative in the initial evaluation of urinary colic. New low-dose protocols and strategies have been developed to contain radiation exposure, which is a major issue especially in specific circumstances.

PATIENT SUMMARY

Noncontrast-enhanced computer tomography has been increasingly used for the diagnosis and management of urinary stones. Low-dose protocols as well as alternative imaging should be considered by clinicians in specific circumstances to minimise radiation exposure.

Clinical significance of residual fragments in 2015: impact, detection, and how to avoid them

PURPOSE

Residual fragments are common after stone treatment. Little is known about clinical outcomes relevant to the patient. This comprehensive review of the literature highlights the impact of residual fragments, modes of detection, and treatment strategies to avoid residual fragments in shock wave therapy, ureteroscopy, and percutaneous nephrolithotomy.

METHODS

A comprehensive review of current literature was performed using PubMed(®), MEDLINE(®), Embase™, Ovid(®), Google Scholar™, and the Cochrane Library. Publications relevant to the subject were retrieved and critically appraised.

RESULTS

Residual fragments after treatment for urinary stones have a significant impact on a patient's well-being and future course. (Ultra-) low-dose non-contrast computed tomography detects small residuals most reliably. In shock wave lithotripsy, adherence to basic principles helps to improve results. Various techniques and devices facilitate complete stone clearance in conventional and miniaturized percutaneous nephrolithotomy and (flexible) ureteroscopy. Promising new technologies in shock waves, lasers, and robotics (and potentially microrobotics) are on the horizon.

CONCLUSIONS

Residual fragments are relevant to patients. Contemporary treatment of urolithiasis should aim at complete stone clearance.

Correlation of Parathormone and the Serum Values of Acidum Uricum with Calcium Nephrolithiasis Examined by Three Different Methods of Diagnostics

Introduction.

Urolithiasis is a multifactorial disease. Changes in social and economic living conditions have generated changes in chemical composition of urolith too. Although calcium is a predominant crystalline constituent of kidney stones in 80% of cases, metabolic disorders are not the main reason for their formation. Hyperparathyroidism may be a cause of occurrence of calcium lithiasis, however, the biggest number of its occurrence is not a consequence of elevated values of parathormone. Acid uric has a pervasive presence in all body fluids. The serum level of acid uric is determined by its rate of synthesis, rate of excretion by kidney and gastrointestinal tract, and metabolism.

Goal.

The goal of our study is to determine a correlation of calcium lithiasis of the upper part of the urinary tract with the parathormone values and the concomitant values of acidum uricum.

Material and methods.

The study was prospective and included 120 patients with calcium lithiasis of the upper part of urinary tract, divided in three age categories, 20-40 years, 40-60 years and older than 60 years. The diagnosis of calcium lithiasis of the upper part of the urinary tract was made on the basis of urinary tract ultrasonography, and kidney-ureter-bladder radiography (KUB) /intravenous urography (IVU), urine culture and chemical analysis of stone with patients who had a spontaneous emission of stone or following some of the methods for active removal of stone; with some patients non-contrast (NCCT) was carried out too. All patients were subjected to the laboratory analysis of the serum level of acidum uricum and parathormone.

Results.

With observed 120 patients suffering from calcium urolithiasis, who belonged to adult population, no patient had an elevated value of parathormone, while three patients (2.5%) had the values of acidum uricum higher than the reference values. The average value (for both parameters) was the lowest with the youngest patients and vice versa, and only in the group of 40 to 60 years of age there were patients whose values of the acidum uricum parameter was outside the interval of reference values; the other age groups did not have such values. Based on the analysis of the variance, as a statistical method, it was determined that the average values of acidum uricum in different age groups were statistically significantly different, which is not the case for the parameter parathormone. (p>0,05).

Conclusion.

The biggest number of nephrolithiasis is not a consequence of elevated values of parathormone. Hyperuricosemia may be present with calcium urolithiasis, without participation in forming kidney stones, most probably as an indirect sign of the existence of the initial insulin resistance and metabolic disease.

Kidney stones over 2 cm in diameter-between guidelines and individual approach

The prevalence of urolithiasis has been observed to increase during last decades. Kidney stones over 2 cm in diameter are the common urologic problem. European and American Associations of Urology has published guidelines on Urolithiasis and presented the most effective tools to treat large stones. On the other hand many experienced endourologic centres choose other modalities from their armamentarium. All treatment methods are characterized by their efficacy and safety which are usually inversely proportional. It is crucial for patients and physicians to find a golden mean. Percutaneous lithotripsy is still considered treatment of choice with more than 95% efficacy. Less invasive retrograde intrarenal surgery is also less effective, but burdened with lower complication rate. Extracorporeal shockwave lithotripsy is feasible in paediatric patients with acceptable stone free rates. Open surgery (pylolithotomy and anatrophic nephrolithotomy) are almost obsolete techniques. All methods have their pros and cons. Physicians should share decisions regarding treatment modalities with patients.

Don't get caught out! A rare case of a calcified urachal remnant mimicking a bladder calculus

Computer tomography through the kidneys, ureters and bladder (CT KUB) is the mainstay investigation of suspected renal tract calculi. However, several pathologies other than renal tract calculi can cause apparent urinary bladder calcification. We describe the case of a 45 year old man who presented with left sided renal colic. Prone CT KUB performed on admission revealed a calcified urachal remnant mimicking a urinary bladder calculus in the dependent portion of the urinary bladder, confirmed by reviewing the multi-planar reformatted images. This is the first reported case in the literature of this phenomenon. We discuss the importance of using multi-planar reformatted images (MPR) and maximum intensity projection images (MIP), as well as careful review of previous imaging, in making the correct diagnosis. We also discuss the differential diagnoses that should be considered when presented with urinary bladder calcification.

[Imaging for diagnostics of urolithiasis including dual-energy CT]

Patients with stone disease usually present to the urologist with acute colic pain. For the right choice of therapy the diagnosis needs to be confirmed using one of many imaging methods, including ultrasonography, abdominal radiography, intravenous urography, non-contrast-enhanced computed tomography (CT), CT and magnetic resonance imaging (MRI) urography and dual-energy CT. The techniques differ in the availability, diagnostic sensitivity and specificity and level of radiation exposure. Compared to the others dual-energy CT allows distinction between different stone compositions with high accuracy and can affect the choice of therapy. This article on imaging and diagnosis of urolithiasis discusses the different imaging methods and highlights dual-energy CT and its distinctive features.

[The impact of ultrasound in urology]

Ultrasound is of great importance in the diagnosis of acute and chronic diseases in urology, such as kidney colic, testicular torsion, low-grade kidney trauma or for follow-up of vesicoureteral reflux, evaluation of infertility, measurement of residual urinary volume and the detection of cancer. An ultrasound examination is time and cost-effective without exposure to ionizing radiation and is routinely performed by practitioners as well as in the clinical daily routine. With technical innovations, such as contrast-enhanced ultrasound or real time elastography, it would for instance be possible to extend the application field of ultrasound. However, in some fields of investigation ultrasound still lacks accuracy and despite its many advantages the validity of ultrasound findings sometimes has to be verified with computed tomography (CT) or magnetic resonance imaging (MRI).

Emergency department imaging protocol for suspected acute renal colic: re-evaluating our service

OBJECTIVES

The objective of our study is to determine the positive rate for urolithiasis in male and female patients, and evaluate whether there has been any change at our institution in the use and outcome of unenhanced multidetector CT (CT KUB) performed in the emergency department (ER) for patients presenting with suspected acute renal colic.

METHODS

A retrospective review of all 1357 consecutive cases between August 2007 and August 2009 admitted to the ER and investigated with CT KUB.

RESULTS

The positive rate for urolithiasis was 47.5% and the rate of other significant findings was 10%. Female patients had a significantly lower positive rate than male patients (26.8% vs 61.6%, p<0.001). Urological intervention was required in 37% and these patients had a larger average stone size. In young female patients with a significantly sized ureteric calculus (>4 mm), the presence of hydronephrosis vs no hydronephrosis was 83% vs 17%, respectively. Among them, only three patients required ureteroscopy for stone removal.

CONCLUSION

Contrary to other studies there has been no "indication creep" in the use of CT KUB at our institution. However, the young female patient presenting with suspected urolithiasis presents a particular diagnostic problem, and the significant percentage of negative examinations in females implies that an improvement in current practice is needed. The indiscriminate use of CT KUB in all female patients with flank pain should be avoided, and it is suggested that they should be initially evaluated with ultrasound to detect the presence of hydronephrosis.

Abdominal imaging utilization in the emergency department: trends over two decades

Background

To assess patterns of use of abdominal imaging in the emergency department (ED) from 1990 to 2009.

Methods

We retrospectively reviewed data on adult ED patients treated between 1990 and 2009 at our university-affiliated quaternary care institution. Examinations were coded by abdominal imaging modality: x-ray, sonography, CT, or MRI. Proportional costs for each imaging modality were evaluated using relative value units (RVUs). Chi-square tests were used to assess for significant trends.

Results

The intensity of abdominal imaging per 1,000 ED visits increased 19.3% from 1990-2009 (p = 0.0050). The number of abdominal CT scans per 1,000 ED visits increased 17.5-fold (p < 0.0001). Similarly, the number of abdominal MRIs per 1,000 ED visits increased from 0 to 1.0 (p < 0.0001), and the number of abdominal sonographs per 1,000 ED visits increased 51.6% (p = 0.0198). However, the number of x-ray examinations per 1,000 ED visits decreased 81.6% (p < 0.0001). Abdominal imaging RVUs per 1,000 ED visits increased 2.7-fold (p < 0.0001), due primarily to CT imaging, which accounted for 14% of RVUs in 1990 and 76% of RVUs in 2009.

Conclusions

The intensity of abdominal imaging examinations per 1,000 ED visits and the number of abdominal imaging RVUs increased significantly over a 20-year period. CT replaced x-ray as the most common abdominal imaging modality for evaluation of ED patients. In light of these increasing costs as well as the increased radiation exposure of CT, clinical decision rules and computerized decision support may be needed to ensure appropriate utilization of abdominal CT in the ED.

Single Session Cystolitholapaxy and PCNL for Encrusted DJ Stent with Large Associated Stone Burden

Introduction

Ureteral stent use is commonplace in urology to prevent or relieve ureteral obstruction. If ureteral stents are neglected, they can cause severe morbidity due to migration, occlusion, encrustation, breakage, stone formation, and even death, due to life-threatening urosepsis or complications related to operative intervention. Extracorporeal Shockwave lithotripsy, ureterorenoscopy electro-hydraulic lithotripsy, laser lithotripsy, and percutaneous nephrolitholapaxy (PCNL) have been reported for forgotten ureteral stent management, but currently there are no guidelines for this challenging situation and only few algorithms have been introduced by some studies.

Methods

We present a case of a man presenting with an encrusted left double J (DJ) stent, inserted two years before, and bulky radiolucent lithiasis at both ends of the stent. The patient was studied with intravenous pyelogram and non contrast-enhanced computed tomography, and then treated with cystolithotripsy and PCNL in a single session. RESULTS. Complete clearance of the stones was obtained and the DJ stent was removed without breaking from the percutaneous access.

Conclusions

Neglected stents still represent a challenge in urology: while endourology remains the best option for treatment, the management of ureteral stents should be based on follow-up and prevention, using for example a computerized warning and stent retrieval software system.