Imaging for urolithiasis: standards, trends, and radiation exposure.

PURPOSE OF REVIEW: To discuss current trends in imaging for urolithiasis and review the recent scientific literature surrounding this topic. Specifically, to address the efforts urologist should be making to reduce the use of ionizing radiation and to examine alternatives to computerized tomography (CT) scan in diagnosing and managing patients with stones. RECENT FINDINGS: Although CT remains the gold standard for diagnosing urolithiasis, low-dose and ultralow-dose CT scans should be utilized more frequently. Imaging with ultrasound and digital tomosynthesis, especially in follow-up for urolithiasis, offers the dual benefit of reduced patient radiation exposure and acceptable diagnostic ability. SUMMARY: Urolithiasis is a prevalent and recurrent condition and patient radiation exposure throughout diagnosis and management of this disease needs to be considered. Imaging modalities that limit radiation and preserve diagnostic accuracy must be utilized.

Computed Tomography Urography: State of the Art and Beyond.

Computed Tomography Urography (CTU) is a multiphase CT examination optimized for imaging kidneys, ureters, and bladder, complemented by post-contrast excretory phase imaging. Different protocols are available for contrast administration and image acquisition and timing, with different strengths and limits, mainly related to kidney enhancement, ureters distension and opacification, and radiation exposure. The availability of new reconstruction algorithms, such as iterative and deep-learning-based reconstruction has dramatically improved the image quality and reducing radiation exposure at the same time. Dual-Energy Computed Tomography also has an important role in this type of examination, with the possibility of renal stone characterization, the availability of synthetic unenhanced phases to reduce radiation dose, and the availability of iodine maps for a better interpretation of renal masses. We also describe the new artificial intelligence applications for CTU, focusing on radiomics to predict tumor grading and patients' outcome for a personalized therapeutic approach. In this narrative review, we provide a comprehensive overview of CTU from the traditional to the newest acquisition techniques and reconstruction algorithms, and the possibility of advanced imaging interpretation to provide an up-to-date guide for radiologists who want to better comprehend this technique.

Genitourinary imaging: current and emerging applications.

This review discusses the current and emerging techniques in urinary tract imaging. Recent technical advances and novel discoveries make this an exciting but challenging time for urinary tract imaging. The first section describes the imaging of the adrenal gland which has made great strides in the last decade, the current major adrenal imaging modalities as well as new applications are discussed with particular attention to the role of imaging in the incidentally detected adrenal lesion. In the second section the role of ultrasound, computed tomography (CT) and magnetic resonance (MR) in evaluation of the renal tract are discussed with the new technical advances leading to earlier detection and characterization of renal lesions. Complementary to this is the emerging role of CT and MR urography in assessment of the urinary tract and bladder in contrast to the demise of plain film studies/intravenous urography. The role of CT angiography in assessment of the renal vasculature is also discussed. The third section discusses the role of prostate imaging in the diagnosis, staging and management of prostate cancer. Transrectal ultrasonography, can be used to guide biopsy, CT is frequently used in staging, with bone scintigraphy and positron emission tomography having roles in advanced disease. Currently, all imaging modalities, especially MR are evolving to improve disease detection and staging. The final section discusses the recently encountered adverse reaction of nephrogenic systemic fibrosis in patients post gadolinium-enhanced MRI and how to help prevent this adverse reaction.

Voiding cystography practices and preferences of North American pediatric urologists.

PURPOSE: Little consensus exists regarding the choice of a specific modality of voiding cystography in the evaluation and management of vesicoureteral reflux. We hypothesized that choices of pediatric urologists are based on technical factors of the studies themselves, as well as institutional factors unique to their hospital(s). Therefore, we surveyed pediatric urologists to determine their current practices and preferences of modalities of voiding cystography. MATERIALS AND METHODS: We mailed an anonymous survey of 40 questions to all fellows of the American Academy of Pediatrics Section on Urology. RESULTS: Surveys were returned from 186 of 301 fellows (62%). Of the respondents 57% were in academic, 30% in private and 13% in mixed practices. Given a choice of fluoroscopic voiding cystourethrography, radionuclide cystography and voiding ultrasonography, fluoroscopic voiding cystourethrography was preferred by 98% and 96% of respondents for initial evaluation of urinary tract infection in males and females, respectively, 96% for assessment of prenatal hydronephrosis, 54% for followup of vesicoureteral reflux, 59% for screening siblings, and 63% and 66%, respectively, after open and endoscopic correction of vesicoureteral reflux. Voiding ultrasonography was preferred by less than 10% of respondents in all groups, and radionuclide cystography was preferred by the remainder. Voiding images of the urethra, child-friendliness of staff, sensitivity and accuracy were factors most important in choosing a test. Of the respondents 83% reported full-time access to pediatric radiologists at their primary hospital, although a minority had full-time access to pediatric radiologists at additional institutions. Sedation was used in some or most cases by 29%, rarely by 56% and never by 15% of respondents. CONCLUSIONS: Pediatric urologists prefer fluoroscopic voiding cystography in all situations to evaluate vesicoureteral reflux but the proportion varies by indication. Diagnostic and patient issues are of greater concern than radiation dose. Variability in access to pediatric radiologists and ability to obtain the desired study may also alter ordering practices.

Current use of computed tomographic urography: survey of the society of uroradiology.

OBJECTIVE: To determine uroradiologists' opinions and practices regarding computed tomographic (CT) urography. METHODS: A Web-based survey was sent via e-mail to all 259 members of the Society of Uroradiology. Of the 229 successfully delivered e-mails, 90 (39%) members responded. RESULTS: Of 90 uroradiologists, 87% perform CT urography. Compared with intravenous (IV) urography, 69% of uroradiologists use CT urography more than 75% of the time urinary tract imaging is requested; 27% stated that CT urography has completely replaced IV urography. Most uroradiologists perform CT urography using multidetector-row CT alone (79%) and use a 3-phase technique (52%) using a single injection (76%) of contrast material at 3 mL/s (52%) without a compression device (81%) and with the patient in supine position (80%). CONCLUSIONS: Most uroradiologists use CT urography in their practice today; some no longer perform IV urography. Variability in multidetector-row CT technique suggests that more research is needed to determine the optimal protocol.

Magnetic resonance urography update--are we there yet?

Magnetic resonance (MR) urography, in conjunction with traditional MR imaging sequences, offers the potential for a comprehensive evaluation of the entire urinary tract. In addition to defining anatomic form, MR imaging excels at tissue differentiation and can estimate renal function. Most importantly, this information can be obtained without ionizing radiation or iodinated contrast media. Therefore, MR urography has become of particular interest in certain populations, including children, pregnant women, and renal transplant donors and recipients. Despite the challenges inherent in imaging a dynamic system with often subtle abnormalities, recent advances in MR technology and field strength, coupled with expanding functional capabilities, promise a bright future for MR urography.

Changing Abdominal Imaging Utilization Patterns: Perspectives From Medicare Beneficiaries Over Two Decades.

PURPOSE: To assess changing utilization patterns of abdominal imaging in the Medicare fee-for-service population over the past two decades. METHODS: Medicare Physician Supplier Procedure Summary master files from 1994 through 2012 were used to study changes in the frequency and utilization rates (per 1,000 Medicare beneficiaries per year) of abdominal CT, MRI, ultrasound, and radiography. RESULTS: In Medicare beneficiaries, the most frequently performed abdominal imaging modality changed from radiography in 1994 (207.4 per 1,000 beneficiaries) to CT in 2012 (169.0 per 1,000). Utilization rates of abdominal MR (1037.5%), CT (197.0%), and ultrasound (38.0%) all increased from 1994-2012 (but declined briefly from 2007 to 2009). A dramatic 20-year utilization rate decline occurred for gastrointestinal fluoroscopic examinations (-91.9% barium enema, -80.0% upper gastrointestinal series) and urologic radiographic examinations (-95.3%). Radiologists were the dominant providers of all modalities, accounting for >90% of CT and MR studies, and >75% of most ultrasound examination types. CONCLUSIONS: Medicare utilization of abdominal imaging has markedly changed over the past two decades, with overall dramatic increases in CT and MRI and dramatic decreases in gastrointestinal fluoroscopic and urologic radiographic imaging. Despite these changes, radiologists remain the dominant providers in all abdominal imaging modalities.

Trends in the utilization of imaging for upper tract urothelial carcinoma.

OBJECTIVES: To evaluate the changes in use of the different imaging modalities for diagnosing upper tract urothelial carcinoma (UTUC) and assess how these changes have affected tumor stage at the time of surgery. MATERIALS AND METHODS: We assessed the Surveillance, Epidemiology, and End Results (SEER) cancer registry and linked Medicare claims data (1992-2009) for 5377 patients who underwent surgery for UTUC. We utilized International Classification of Disease-Oncology 3 codes to identify UTUC. International Classification of Disease, ninth Revision, Clinical Modification and Current Procedure Terminology codes identified surgical treatment and imaging modalities. We assessed for use of intravenous pyelography, retrograde pyelography (RGP), computed tomography urography (CTU), magnetic resonance urography (MRU), and endoscopy. For each modality, patients were categorized as having received the modality at least once or not at all. Patient characteristics were compared using chi-squared tests. Usage of imaging modalities and tumor stage was trended using Cochran-Armitage tests. We stratified our data into 2 multivariate logistic regression models to determine the effect of imaging modalities on tumor stage: 1992 to 1999 with all modalities except MRU, and 2000 to 2009 with all modalities. RESULTS: Our patient population was predominantly White males of more than 70 years old. Intravenous pyelography and RGP declined in use (62% and 72% in 1992 vs. 6% and 58% in 2009, respectively) while computed tomography urography, MRU, and endoscopy increased in use (2%, 0%, and 37% in 1992 vs. 44%, 6%, and 66% in 2009, respectively). In both regression analyses, endoscopy was associated with lower-stage tumors. In the 2000 to 2009 model, RGP was associated with lower-stage tumors, and MRU was associated with higher-stage tumors. Finally, our data showed an increasing number of modalities utilized for each patient (1% receiving 4 modalities in 1992 vs. 20% in 2009). CONCLUSIONS: We found trends toward the utilization of newer imaging modalities to diagnose UTUC and more modalities per patient. Endoscopy and RGP were associated with smaller tumors, whereas MRU was associated with larger tumors. Further studies are needed to evaluate the utility of the different modalities in diagnosing UTUC.

Diagnosis of vesico-ureteric reflux.

The demonstration and grading of reflux is crucial in examination and follow-up of any child with upper urinary tract infection. A variety of factors can influence the occurrence of reflux, e.g. race, genetics, state of maturation of the ureterovesical valve, diuresis, infection and bladder dysfunction, including obstruction and neurogenic disorders. Even when reflux is investigated under strictly standardized conditions, two consecutive bladder fillings frequently show different grades of reflux. Voiding cystourethrography is, to date, the only method with a generally accepted, well-defined grading of reflux. It also allows detection of intrarenal reflux and anatomical and functional information about the bladder and urethra that is unobtainable by other methods. It is therefore usually considered the method of choice. Radionuclide cystography and, possibly, contrast enhanced ultrasonography can be complementary to voiding cystourethrography, but mainly for postoperative follow-up and screening of siblings.

Radiological investigations following urinary tract infection: changes in Australian practice.

OBJECTIVE: To examine practice changes in the conduct of radiological investigations in Australia following urinary tract infection (UTI). DESIGN: Observational study using data from the national Medicare database over the 15-year period July 1993 to June 2008 for four investigations: renal ultrasound (renal US), micturating cystourethrography (MCU), intravenous pyelography (IVP) and nuclear medicine isotope scanning of the renal tract (NM). Rates per 100,000 children in the age groups 0-4 years and 5-14 years were calculated for each test. SETTING: Australian medical practice, including private and public medical settings. RESULTS: The rates of performance of renal US remained fairly constant throughout the study period in both age groups, while those for MCU, IVP and NM showed a strong falling trend over time for each test in both age groups. For the more invasive tests (MCU, IVP and NM) the total number performed per annum fell from 11,169 (costing 2,032,621 dollars) to 3361 (costing 689,742 dollars) in the last 10 years. CONCLUSION: There have been very marked practice changes over the last 10-15 years. This trend followed the publication of scientific evidence which has raised doubts about the benefit of performing these investigations.

Computed tomography urography: trends in positivity rates over time.

PURPOSE: To investigate changes in usage of computed tomography urography (CTU), indications for CTU, and rates of positive findings over time. METHODS: Retrospective review of data from April 2000 to December 2005 assessed rates of overall positive findings, rates of suspected transitional cell carcinomas (TCCs), benign genitourinary (GU), and significant non-GU findings. Data were analyzed based on specialty of ordering physicians and on requisition indications. RESULTS: One thousand two hundred seventy-one patients had 1746 CTUs, including 952 men (1259 studies) and 319 women (487 studies) with mean age of 61 years. Computed tomography urographies increased from 265 in 2001 to 443 in 2004. Eighty-nine percent were ordered by urologists, 4% by oncologists, 1% by emergency physicians, and 6% by other specialties. Sixty-two percent of first-time studies were ordered for possible GU malignancy, 24% for hematuria, and 14% for other reasons. Eight hundred sixty-one examinations (49%) showed significant findings. The rate of all positive examinations, analyzed in 6-month periods, varied from 37% to 54%, but no time trend was identified. First-time patient examinations had positive examinations in 46% to 62% of cases. Similarly, no trends were found for examinations interpreted as possible TCC (17%-32%), renal stones (9%-18%), renal masses (1%-6%), causes of hematuria (15%-26%), and acute non-GU findings (2%-9%). The rate of positive findings by ordering specialty varied minimally from 49% to 53%. No change occurred in the proportions of indications for CTU over time. CONCLUSIONS: In 5 years, the number of CTU examinations per year increased 1.5-fold. The rate of CTU findings positive for suspected TCC, stones, and other causes of hematuria showed no decline or increase. If precautions are taken regarding proper indications for CTU, the overall rates of positive findings may not substantially change over time, thereby only submitting high-risk patients to this examination.

Is there a role for the intravenous urogram in the 21st century?

Over the last two decades, there have been major advances in methods of medical imaging that have brought great benefits to patients both for diagnosis and for treatment. There has been an increasing tendency for some of these new imaging modalities to be dependent on highly sophisticated technology. The belief has developed amongst doctors who use these techniques that newer is necessarily better. Just as patients (and some doctors) now often believe that anything done with a laser represents the best that can be offered, so there is a tendency to demand that newer techniques in imaging should always be offered as the preferred option. In urological practice that philosophy is questionable.

Pediatric uroradiology--1997.

The imaging of common pediatric urological problems is in evolution. Modifications of standard techniques such as substitution of cyclic voiding cystourethrography in the neonate and infants, introduction of newer modalities (Doppler ultrasound), and new nuclear renal agents (Tc-MAG3) have enhanced our ability to detect anomalies and abnormalities. In this brief article, some of the recent developments in imaging are reviewed and the ways in which these developments interface with traditional imaging studies are presented.

Radiological examinations of the urinary tract. Changes during the last 24 years.

Procedures for imaging the urinary tract have been recorded in six Norwegian hospitals for the last 24 years. For three of the hospitals, data were collected from 1965 to 1989, and for the other three from 1966, 1971 and 1975, respectively. There was a significant reduction in the number of intravenous pyelograms, voiding cystograms, and renal angiograms, but the number of retrograde pyelograms and plain radiographs of the urinary tract remained constant. Computed tomography of the urinary tract increased during the first years, but after the introduction of ultrasonography, the number of computed tomograms decreased. Ultrasonographic examinations of the urinary tract are still rapidly increasing, and seem to have replaced some of the other imaging techniques. The present results should be taken into consideration when planning the health care for the future.

[Changes in perioperative treatment for elective colorectal resections in Germany 1991 and 2001/2002]. / Wandel der perioperativen Therapie bei elektiven kolorektalen Resektionen in Deutschland 1991 und 2001/2002.

BACKGROUND: To assess changes in perioperative treatment of patients undergoing elective colorectal resections, surveys were sent to all German surgical departments in 1991 and 2001/2002. METHODS: 1,207 chairmen of departments for general or visceral surgery were asked to answer a survey concerning the principles of perioperative treatment of patients undergoing elective colorectal resection. The results of this questionnaire were compared to a survey that had been performed in 1991. RESULTS: 616 chairmen (51.0%) responded to the survey (1991: 76.4%). In 2001/2002 preoperative parenteral alimentation was utilized routinely in only 10.3% (1991: 40.0%) of all hospitals. Preoperative i.v.-pyelography was used only in 24.7% of the hospitals (1991: 79.7%). Intraoperative testing of colorectal anastomoses was more common in 2001/2002 (63.7%) than in 1991 (40.1%). At the same time the incidence of "single-shot"-antibiotic prophylaxis increased from 24.0% to 70.4 %. Orthograde bowel lavage, perioperative antibiotic prophylaxis and postoperative parenteral alimentation were use as often in 2001/2002 as in 1991. Intraperitoneal drains were routinely inserted in most of the surgical departments after left-sided colonic resections (2001/2002: 86.2%; 1991: 88.2%) or rectal resections (2001/2002: 90.5%; 1991: 94.4%). CONCLUSION: During the last decade, perioperative therapy for patients undergoing elective colorectal resection has changed substantially. Most of these changes occurred in the perioperative medical treatment. However, surgical traditions like intraperitoneal drainage are still very frequently utilized.

Trends in pediatric uroradiology.

Excretory urography, conventional and radionuclide voiding cysto(urethro)graphy, ultrasonography, radionuclide renal imaging and computed tomography are all currently readily available in most locales for the evaluation of the child's urinary tract. It is the responsibility of the radiologist to determine which studies are best for which children and the order in which they should be performed to minimize "cost" while maximizing the information obtained. A description of such an approach and its consequences are presented.

La uroresonancia. Una alternativa diagnóstica / UroMRI, a diagnostic alternative

Objetivos: Este trabajo pretende evaluar la utilidad clínica y diagnóstica de la Uroresonancia (URM), mostrar la técnica del estudio y correlacionar algunos de sus resultados con el Urograma Excretor Convencional (UEC). Se evaluó la frecuencia de las patologías encontradas y su prevalencia por edad y sexo. Métodos: Se estudiaron un total de 58 pacientes, 31 mujeres y 27 hombres; con un rango de edad entre 22 a 92 años, a los cuales se les realizó la URM desde Abril de 2003 a Enero de 2005. Se hizo un estudio doble ciego con aquellos pacientes en los cuales se habían realizado el UEC previo a la URM. Resultado: El total de los pacientes evaluados fueron 58, de los cuales 35 presentaron mas de una patología coexistente. Se obtuvieron 17,2% (n: 10) de estudios normales, 5 hombres y 5 mujeres, con un rango de edad entre: 22 a 83 años, siendo la edad promedio de 46,1 años. Para la litiasis renal el UEC fue diagnostico del 100% y el 83,3%; y para la URM el 50% y el 0% en los observadores A y B respectivamente. La litiasis ureteral en el UEC mostró un resultado del 50% y el 100%; y con la URM el 75% para ambos observadores. En los casos de doble sistema pielocalicial ambos métodos tienen el 100% de acuerdo entre ambos observadores. En el cáncer de vejiga la URM, con el 100% y el UEC con el 0% para ambos observadores. Conclusiones: La patología coexistente más frecuente fue la enfermedad quística renal y en segundo término la urolitiasis con dilatación del sistema excretor. La URM resultó ser superior para la visualización de las patologías vesicales y pieloureterales, pero en los casos de litiasis renal y en las calcificaciones del aparato urinario el UEC sigue siendo el método de elección (AU)

Objectives: This paper aims to evaluate the clinical and diagnostic usefulness of uro MRI, to show the study technique and to establish correlations of some of its results with conventional intravenous urography (IVU). Frequency and prevalence by age and gender of pathologies were evaluated. Methods: We studied a total of 58 patients, 31 females and 27 males, with an age range between 22-92 years. All patients underwent uro MRI between April 2003 and January 2005. We perform a double-blind study with those patients undergoing conventional IVU before uro MRI. Results: The total number of patients evaluated was 58, 35 of which present more than 1 concurrent pathology. 17.2% (n = 10) of the studies were normal, five males and five females, with an age range between 22 and 83 years, and a mean age of 46.1 years. IVU was diagnostic for 100% and 83.3% of A and B observers respectively; uro MRI was diagnostic for 50% and 0% respectively. Ureteral lithiasis showed a result of 50% and 100% for IVU; uro MRI had a 75% for both observers. In cases of double pyelocalyceal system both methods have a 100% accordance between both observers. In bladder cancer, uro MRI was diagnostic in 100% and IVU in 0% for both observers. Conclusions: The most frequent concurrent pathology was cystic renal disease, and the second was urolithiasis with urinary tract dilation. Uro MRI was superior to see bladder and pyeloureteral pathologies, but in cases of renal lithiasis and urinary tract calcifications IVU is the test of choice yet (AU)