INDICATION OVERVIEW

Obstructive uropathy can be defined as any blockage of urine drainage from the kidney (renal calyces or renal pelvis), ureter, or bladder.¹ As a result of the blockage, urine backs up into the kidneys, causing dilatation of the ureter, renal pelvis, and renal calyces, which can damage the kidney if it is not treated. The appearance of dilated or enlarged renal pelvis and calyces is referred to as hydronephrosis and is a symptom of obstructive uropathy.² Obstructive uropathy can be a long-term disease (chronic) or occur suddenly (acute). As well, it can occur in one kidney (unilateral) or both kidneys (bilateral).² Symptoms may include nausea, vomiting, excessive sweating (diaphoresis), and abdominal or groin pain.³

There are many causes of obstructive uropathy; however, the most common causes include stones in kidneys (nephrolithiasis),⁴ ureter (ureterolithiasis) or anywhere in the urinary tract (urolithiasis).^5,6 Other causes of obstructive uropathy include health conditions such as pregnancy, prostate cancer,² retroperitoneal fibrosis,⁷ spinal cord injury,^8,9 ureteral stricture,⁶ and congenital anomalies (e.g., ureteropelvic junction obstruction [UJO]),^5,10 which is most common in children but also occurs in adults.⁶ The gold standard to assess urinary obstruction is unclear;^11–13 therefore, several imaging modalities are often used.⁸

Population: Adults and children with chronic and acute urinary obstruction presenting with symptoms including renal colic, suspected urinary obstruction symptoms (e.g., evidence of hydronephrosis), impaired renal function.

Intervention: Renal scintigraphy (renal scan). Synonyms for renal scan in the literature and in clinical practice include diuresis renography, renal flow studies, radioisotope renography,⁸ Lasix renography (Patrick Au, Acute and Emergency Services Branch, Saskatchewan Ministry of Health: unpublished data, 2011), and nuclear medicine renogram.¹⁴ The terms renal scintigraphy and renal scan will be used throughout this report.

Renal scanning begins with intravenous (IV) administration of a radiotracer immediately followed by acquisition of images for 20 to 30 minutes.¹⁵ An external gamma camera detects emission of gamma rays emitted by the radiotracer, which is reflective of the distribution of radiotracer in the patient. Radiotracers currently used in Canada include technetium-99m-labelled mercaptoacetyl trigylcine (^99mTc-MAG3), technetium-99m-labelled- diethylenetriamine pentaacetic acid acid (^99mTc-DTPA), or technetium-99m-labelled-dimercaptosuccinic acid (^99mTc-DMSA).

^99mTc-MAG3 and ^99mTc-DTPA are rapidly taken up by the kidney and then excreted through the urinary tract. Their mechanism of renal uptake and imaging characteristics, however, differ — ^99mTc-DTPA is taken up by the kidney through glomerular filtration and is not secreted or reabsorbed by the renal tubules, whereas ^99mTc-MAG3 is mostly taken up by the proximal renal tubules and its high plasma protein binding prevents it from being filtered through the glomerular membrane. Once ^99mTc-DTPA reaches the kidney, it is then excreted by filtration. Hence, the glomerular filtration rate (GFR) quantifies the amount of filtrate formed per minute (normal GFR: ~ 120 mL/min in adults). Conversely, clearance of ^99mTc-MAG3 is expressed as the effective renal plasma flow (ERPF) — an approximation of renal plasma flow (normal ERPF: ~ 600 mL/min in adults). ^99mTc-DMSA remains in the renal parenchyma for an extended period and is used for static renal scintigraphy. ^99mTc-DMSA accumulates in the functioning renal cortex, and impaired renal cortex and space-occupying lesions are depicted as hypoactive areas.¹⁶

The diuretic, furosemide (Lasix), is then administered by IV, and a second series of images is acquired for an additional 20 to 30 minutes while the bladder empties.¹⁵ The images gathered as the bladder empties help to calculate a filtration rate that provides information regarding how well the kidney is functioning and if there is an obstruction.¹⁷ These images are used to calculate the clearance rate of the radiotracer, which is measured by the following outcomes: renal transit time (RTT),¹⁴ and washout half-time (T_1/2).^18,19 If the patient has problems emptying his or her bladder, a urinary catheter may be used.¹⁶

Comparators: For this report, the following diagnostic tests are considered as alternatives to renal scintigraphy:

• Magnetic Resonance Urography (MRU): MRU requires a magnetic resonance (MR) scanner. Patients undergoing MRU are given fluids to hydrate the body. A sedative may be administered (usually in children) at this point, and a catheter (usually in children) may also be given to the patient so that the flow of urine can be observed without the patient having to go to the washroom during the procedure. A diuretic, typically furosemide (Lasix) is administered and images are taken with the MRI machine. A contrast agent (gadolinium [Gd]) is also administered, usually 15 minutes after the diuretic, and more images are taken to measure the volume of the kidney and how the urine accumulates, in order to calculate measurements that determine the renal function.^12,14,20
• Ultrasound (U/S): During a U/S, a transducer is placed over the organ of interest. The transducer produces sound waves that pass through the body. As the sound waves pass through the body, they produce echoes that are analyzed by a computer to produce images of the body part being analyzed.²¹ When there is a presence of obstruction in the renal tract, obstruction is diagnosed primarily by the appearance of hydronephrosis (expert opinion — Martin Reed). Obstruction in the kidney may also cause a decrease in blood flow that can be measured as an increase in vascular resistance (arterial resistance),^17,18 referred to as the renal resistive index (RI). Generally, an RI less than or equal to 0.70 means kidney function is normal,^9,17 while an RI greater than 0.70 suggests an obstructed kidney.²² In children younger than six months, an RI greater than 0.9 is borderline obstructive hydronephrosis.¹⁸ Doppler ultrasound, which is a type of ultrasound that shows images in colour, can distinguish between obstructive and non-obstructive pyelocaliectasis¹⁷ and show a wave-like (peristaltic)²³ inflow into the bladder (ureterovesical or urinary jet). If a urinary jet is absent, this can also be indicative of obstruction.^17,19 Relative jet frequency is the measure used to diagnosis presence of jets indicative of obstruction.¹⁹

Other possible comparators could include the Whitaker test, which has been largely replaced by computed tomography (CT) and U/S (expert opinion — Martin Reed and Eric Turcotte). Retrograde pyelography is a surgical technique and is used primarily for cancer diagnosis rather than obstruction assessment (expert opinion — Martin Reed and Eric Turcotte). Both of these comparators were excluded from this report. Renal scan with ¹²³I-orthoiodohippurate (¹²³I-OIH) uses the same approach as the ^99mTc-based renal scan.²⁴ No information regarding ¹²³I-OIH renal scan related to the criteria was identified in the literature. (Note: ¹²³I-OIH is not currently available on the Canadian market and when it was, the T_1/2 of 13 hours limited its availability; expert opinion —Gilbert Matte.)

Outcomes: Eleven outcomes (referred to as criteria) are considered in this report:

• Criterion 1: Size of the affected population
• Criterion 2 : Timeliness and urgency of test results in planning patient management
• Criterion 3: Impact of not performing a diagnostic imaging test on mortality related to the underlying condition
• Criterion 4: Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition
• Criterion 5: Relative impact on health disparities
• Criterion 6: Relative acceptability of the test to patients
• Criterion 7: Relative diagnostic accuracy of the test
• Criterion 8: Relative risks associated with the test
• Criterion 9: Relative availability of personnel with expertise and experience required for the test
• Criterion 10: Accessibility of alternative tests (equipment and wait times)
• Criterion 11: Relative cost of the test.

Definitions of the criteria are in Appendix 1.

METHODS

The literature search was performed by an information specialist using a peer-reviewed search strategy.

Published literature was identified by searching the following bibliographic databases: MEDLINE with In-Process records via Ovid; The Cochrane Library (2011, Issue 1) via Wiley; PubMed; and University of York Centre for Reviews and Dissemination (CRD) databases. The search strategy was comprised of both controlled vocabulary, such as the National Library of Medicine’s MeSH (Medical Subject Headings), and keywords. The main search concepts were radionuclide imaging and obstructive uropathy.

Methodological filters were applied to limit retrieval to health technology assessments, systematic reviews, meta-analyses (HTA/SR/MA), randomized controlled trials, and non-randomized studies, including diagnostic accuracy studies. No date or human limits were applied to the HTA/SR/MA search. For primary studies, the retrieval was limited to documents published between January 1, 2001 and April 1, 2011, and the human population. Both searches were also limited to English language documents. Regular alerts were established to update the search until October 2011. Detailed search strategies are located in Appendix 2.

Grey literature (literature that is not commercially published) was identified by searching relevant sections of the CADTH Grey Matters checklist. Google was used to search for additional web-based materials. The searches were supplemented by reviewing the bibliographies of key papers. See Appendix 2 for more information on the grey literature search strategy.

Targeted searches were done as required for the criteria, using the aforementioned databases and Internet search engines. When no literature was identified that addressed specific criteria, experts were consulted.

SEARCH RESULTS

The literature search identified 34 HTA/SR/MA and 816 primary studies. From the HTA/SR/MA, 13 potential articles underwent full-text screening. From the primary studies, 142 articles underwent full-text screening.

No applicable HTA/SR/MA were identified with information to address Criterion 7 on the relative diagnostic accuracy of tests. Eight applicable primary studies were identified for this criterion (three relevant for adult population and five relevant for children), and 32 articles reported information for the following criteria: 1) Size of the affected population; 2) Timeliness and urgency of test results in planning patient management; 3) Impact of not performing a diagnostic imaging test on mortality related to the underlying condition; 4) Impact of not performing a diagnostic imaging test on morbidity or quality of life related to the underlying condition; 5) Relative impact on health disparities; 6) Relative patient acceptability of test; 8) Relative risks associated with the test; and 9) Relative availability of expertise and experience required for the test.

The remaining citations were either articles found through searching the grey literature, articles from targeted searches, or articles from the reference lists.

SUMMARY TABLE

Table 1. Summary of Criterion Evidence (PDF, 213K)

CRITERION 7: Relative diagnostic accuracy of the test (link to definition)

Adult

No meta-analyses or systematic reviews with information regarding the diagnostic accuracy specific to an adult population was found; however, three primary studies^8,35,36 were identified that compared U/S, MRU, or CT to renal scans using ^99mTc-MAG3 or ^99mTc-DTPA. Only those studies that evaluated patients for an initial diagnosis of obstruction were included. Studies that evaluated obstruction after surgery or intervention for clearance of obstruction were not included. The main outcomes that were reported for diagnostic accuracy were the correlation coefficient of the renal scan compared with the alternative imaging test and, in some cases, sensitivity and specificity were reported (Appendix 4).

Results of the accuracy of diagnosis of hydronephrosis by renal scan and U/S are summarized in Table 2.

Table 2

Summary of Diagnostic Accuracy Measures of Tests in Adult Renal Obstructive Uropathy.

Renal scintigraphy versus MRU

Abou El-Ghar et al.³⁵ assessed the role of MRU and renal scintigraphy for the anatomical and functional evaluation of obstructed kidneys. A total of 96 patients (59 males, 37 female) with compromised renal function were included in the study (mean age = 52.5 ±14 years). All included patients underwent Gd-enhanced MRI and ^99mTc-DTPA renal scan. Diagnosis of obstruction was confirmed by ureterogram or endoscopy and/or open surgery (gold standard). Anatomically, MRI detected the cause of the obstruction in all kidneys with non-calcular obstruction (100% sensitivity) and in 21 kidneys with calcular obstruction (70% sensitivity). When combined with abdominal X-ray and ultrasonography, the sensitivity of MRI in detection of cause of obstruction was 97%. Functionally, a comparison between Gd-enhanced MRI and ^99mTc-DTPA renal scan showed a good correlation (r = 0.79, P < 0.0001); the mean GFR value for the compromised kidneys was 14.6 ± 6 mL/min for the MRU and 18 ± 4.9ml min⁻¹ for the renal scan. The authors concluded that the MRU is as accurate as renal scan in assessing renal function and could be used as a single modality for diagnosing obstruction in cases where patients would not be compromised due to renal function contraindications.³⁵

El-Nahas et al.³⁶ evaluated the diagnostic accuracy of MRU in comparison with renal scan in 46 patients with pelvic-UJO (22 males, 24 females; mean age 31.6 years). All patients underwent ^99mTc-MAG3 renal renography, while renal U/S or intravenous urography were also conducted for morphological changes. The clearance of the agents as assessed by both MRU and renal scan were calculated and compared using a correlation coefficient. The mean value of the MRU clearance was 32.8 mL/min, while the renal scan was 31.6 mL/min. The difference between the two tests was not statistically significant (P = 0.19); however, the correlation between the two values was (r = 0.82; P < 0.001). The authors concluded that there is a strong correlation between MRU and renal scan clearance, which can be attributed to the high accuracy of MRU in calculating renal clearance and diagnosing obstructive uropathy.³⁶

Renal scintigraphy versus U/S

A 2001 study by Tsai et al.⁸ evaluated the diagnostic accuracy of U/S and renal scan in the detection of hydronephrosis in patients with spinal cord injury (SCI) using intravenous pyelogram as the gold standard.⁸ A total of 109 patients with SCI and hydronephrosis were evaluated over a three-year period from 1993 to 1996 at a rehabilitation hospital in Taiwan. The mean age of the group was 33.7 years and the main outcome measure was the ERPF using the radiopharmaceutical ^99mTc-MAG3. Of analyzed kidneys, U/S correctly excluded the presence the hydronephrosis in 173 of 192 non-obstructed kidneys and positively identified 41 of 43 kidneys with documented hydronephrosis. The renal scan correctly excluded 161 non-obstructed kidneys and correctly identified 39 of 43 kidneys with hydronephrosis.⁸ The corresponding sensitivity of U/S was 0.96, with a specificity of 0.91. Renal scan reached a sensitivity of 0.91 with a specificity of 0.84. The authors conclude that U/S was more accurate than renal scintigraphy for the detection of hydronephrosis in patients with SCI, although they add that renal scintigraphy can provide valuable information regarding total and individual renal function, which cannot be obtained by U/S alone.⁸

Table 2 presents a summary of diagnostic accuracy measures of imaging tests in adults with renal obstructive uropathy.

Pediatric

No meta-analyses or systematic reviews with information regarding the diagnostic accuracy specific to a pediatric population was found; however, five^{12,14,18–20} primary studies were found that evaluated diagnostic accuracy of MRU and U/S in comparison with a radioisotope renal scan in a pediatric population of renal obstructive uropathy. Studies that included a population of children with renal obstructive uropathy that were diagnosed via U/S in the womb and were being evaluated after birth for a confirmation of diagnosis prior to surgical intervention were excluded.

Renal scintigraphy versus MRU

Jones et al.¹⁴

A study conducted by Jones and colleagues between November 2001 and September 2003 involved a total of 137 children in order to diagnose obstructive uropathy. MRU and renal scan with ^99mTc DTPA (hence calculation of GFR) or ^99mTc MAG3 (hence ERFP) were conducted on all the participants. The majority of the patient population involved boys (61%) with a mean age of 3.5 ± 4.5 years (range: 0.02 to 15.2 years) and girls (39%) with a mean age of 4.1±4.9 (range: 0.2 to 16.5). The renal transit time and split renal function were calculated as outcomes for the MRU to determine obstruction. Diagnosis of obstruction for renal scan was decided if the T_1/2 washout time was greater than 20 minutes after the administration of the diuretic. In final, data from 30 patients was included and a total of 59 kidneys evaluated. An receiver operating characteristic (roc) curve was generated, and the area under the curve (AUC) was calculated to be 0.90. This value means that the accuracy of MRU was 90% in comparison to renal scan as a gold standard (100%).¹⁴

Perez-Brayfield et al.²⁰

Perez-Bayerfield and colleagues conducted a study to evaluate the role of dynamic enhanced MRI in order to compare it with other imaging modalities in the diagnosis of pediatric hydronephroisis. A total of 96 children (mean age four years) were involved in the study and a total of 100 dynamic contrast MRIs were done along with U/S and renal scan using ^99mTc-MAG3 (n=71), ^99mTc-DTPA (n=39) or ^99mTc-DMSA (n=3). The SRF for nuclear imaging and MRI was compared in 71 of the 100 cases and the correlation coefficient was calculated to be r²=0.93 which yields and r value of 0.96.

Grattan-Smith et al.¹²

Grattan-Smith and colleagues conducted a study to evaluate the role of dynamic enhanced MRI compared with other imaging modalities in the diagnosis of 40 children (mean age 1.4 years) with pediatric hydronephrosis. MRIs were done along with renal scan using ^99mTc-MAG3 (n=22), ^99mTc-DTPA (n=15) or ^99mTc-DMSA (n=2). The SRF for renal scan and MRI was calculated and compared in all 40 cases. The correlation coefficient was calculated to be r=0.98. In conclusion, the authors summarized that in regards to the anatomical function, MRU was superior to renal scan, however, SRF outcomes between MRI and renal scan are equivalent.

Renal scintigraphy versus U/S

de Bessa Junior et al.¹⁹

A study conducted by de Bessa Junior et al. evaluated the diagnostic accuracy of U/S compared to renal scan to identify cases of urinary obstructions. A total of 54 patients were eligible for the study between September 2005 and October 2006; the median age of patients was four years (age range: 3 months to 14 years). All patients underwent U/S and renal scan using ^99mTc-DTPA within a maximum of two weeks. For U/S, obstruction was diagnosed if the ureterovesical jet frequency was less than or equal to 25%. Renal scan was the reference test, and obstruction was diagnosed as a measure of differential renal function less than 40%. The sensitivity and specificity for U/S in comparison to renal scan were calculated to be 87% (95% CI; 78.9% to 98.2%) and 96.4% (95% CI; 87% to 99%), respectively. The positive likelihood ratio and negative likelihood ratio were 24.3 and 0.1 respectively. The authors’ conclude that a relative jet frequency value of less than or equal to 25% was a good indicator of obstructive uropathy and could be used as a non-invasive alternative to renal scan, but the authors state that further research is needed.¹⁹

Table 3Summary of Diagnostic Accuracy Measures of Tests in Pediatric Renal Obstructive Uropathy^{12,14,18–20}

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Test	Correlation Coefficient (R)*	Sensitivity (%),	Specificity (%)	Accuracy
MRU	0.96–0.98	N/A	N/A	0.90
U/S	N/A	87	96.4	N/A

CT = computed tomography; MRU = magnetic resonance urography; N/A= Not available; U/S = ultrasound

*

Between test and renal scan.

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CRITERION 8: Relative risks associated with the test (link to definition)

Non–radiation-related Risks

Renal scan

Adverse events from renal scintigraphy are rare but may include reaction to the radiopharmaceutical, rash, fever, or chills.³⁷ There is also a relative contraindication in the administration of captopril in patients with a solitary kidney, as it may precipitate transient acute renal failure if the kidneys have physiologically significant renal artery stenosis (MIIMAC expert opinion).

MRU

MRI is contraindicated in patients with metallic implants including pacemakers.⁵⁸ MRI is often used in conjunction with the contrast agent Gd. Some patients may experience an allergic reaction to the contrast agent (if required), which may worsen with repeated exposure.⁵⁹ Side effects of Gd include headaches, nausea, and metallic taste. Gd is contraindicated in patients with renal failure or end-stage renal disease, as they are at risk of nephrogenic systemic fibrosis. According to the American College of Radiology Manual on Contrast Media³⁸ the frequency of severe, life-threatening reactions with Gd are extremely rare (0.001% to 0.01%). Moderate reactions resembling an allergic response (i.e., rash, hives, urticaria) are also very unusual and range in frequency from 0.004% to 0.7%.³⁸ Children may require sedation.

U/S

There are no reported risks associated with U/S in the literature that was reviewed.

Radiation-related Risks

Among the modalities to diagnose obstructive uropathy, renal scintigraphy exposes the patient to ionizing radiation. The average effective dose of radiation delivered with each of these procedures can be found in Tables 4 and 5.

Table 4

Effective Radiation Doses for Various Imaging Tests in Adults.

Table 5

Comparison of Radiation Exposure Levels of Different Imaging Tests in Pediatric Patients.

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CRITERION 9: Relative availability of personnel with expertise and experience required for the test (link to definition)

The personnel required for the performance of the imaging tests to evaluate suspected obstructive uropathy are presented by imaging modality. A summary of the availability of personnel required for renal scintigraphy or any of the alternative imaging modalities is provided in Table 6.

Table 6

Medical Imaging Professionals in Canada.

Renal scintigraphy

In Canada, physicians involved in the performance, supervision, and interpretation of renal scans should be nuclear medicine physicians or diagnostic radiologists with training/expertise in nuclear imaging. Physicians should have a Fellowship of Certification in Nuclear Medicine or Diagnostic Radiology with the Royal College of Physicians and Surgeons of Canada and/or the Collège des médecins du Québec. Nuclear medicine technologists are required to conduct renal scans. Technologists must be certified by the Canadian Association of Medical Radiation Technologists (CAMRT) or an equivalent licensing body.

All alternative imaging modalities

In Canada, physicians involved in the performance, supervision, and interpretation of diagnostic MRI and U/S should be diagnostic radiologists⁴⁵ and must have a Fellowship or Certification in Diagnostic Radiology with the Royal College of Physicians and Surgeons of Canada and/or the Collège des médecins du Québec. Foreign-trained radiologists also are qualified if they are certified by a recognized certifying body and hold a valid provincial license.⁶¹

Service engineers are needed for system installation, calibration, and preventive maintenance of the imaging equipment at regularly scheduled intervals. The service engineer's qualification will be ensured by the corporation responsible for service and the manufacturer of the equipment used at the site.

Qualified medical physicists (on site or contracted-part time) should be available for the installation, testing, and ongoing quality control of MRI scanners and nuclear medicine equipment.⁶¹

MRU

MRU is an MRI-based test. For the performance of MRI, medical technologists must have CAMRT certification in magnetic resonance or be certified by an equivalent licensing body recognized by CAMRT.

U/S

Sonographers (or ultrasonographers) should be graduates of an accredited school of sonography or have obtained certification by the Canadian Association of Registered Diagnostic Ultrasound Professionals. They should be members of their national or provincial professional organization. Sonography specialties include general sonography, vascular sonography, and cardiac sonography.⁴⁵ In Quebec, sonographers and medical radiation technologists are grouped together; in the rest of Canada, sonographers are considered a distinct professional group.⁴⁵

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CRITERION 10: Accessibility of alternative tests (equipment and wait times) (link to efinition)

There are notable variations in the availability of medical imaging technologies within hospitals across Canada. Nuclear medicine cameras are not available in the Yukon, the Northwest Territories, and Nunavut. Table 7 provides an overview of the availability of equipment required to diagnose obstructive uropathy. Data for nuclear medicine cameras (including SPECT) are current to January 1, 2007. The number of MRI and SPECT/CT scanners is current to January 1, 2010. Data were not available for U/S.

Table 7

Diagnostic Imaging Equipment in Canada.

Renal scintigraphy

For renal scans, nuclear medicine facilities with gamma cameras (including SPECT) are required. Three jurisdictions — the Yukon, the Northwest Territories, and Nunavut — do not have any nuclear medicine equipment.⁴⁵ In 2007, the latest year for which data are available, the average time for renal scintigraphy in McGill University Health Centre (MUHC) hospitals was 13 days. However, the wait times were reported to be less than one day for emergency cases.⁶²

MRI

There are no MRI scanners available in the Yukon, Northwest Territories, or Nunavut.⁴⁵ According to the Canadian Institute for Health Information’s National Survey of Selected Medical Imaging Equipment database, the average number of hours of operation per week for MRI scanners in 2006–2007 ranged from 40 hours in PEI to 99 hours in Ontario, with a national average of 71 hours.⁴⁵ In 2010, the average wait time for MRI in Canada was 9.8 weeks.⁴⁷

U/S

U/S machines are widely available across the country. According to the Fraser Institute, the average wait time for U/S in 2010 was 4.5 weeks.⁴⁷

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CRITERION 11: Relative cost of the test (link to definition)

Fee codes from the Ontario Schedule of Benefits were used to estimate the relative costs of Lasix-enhanced renal scintigraphy and its alternatives. Technical fees are intended to cover costs incurred by the hospital (i.e., radiopharmaceutical costs, medical/surgical supplies, and non-physician salaries). Maintenance fees are not billed to OHIP — estimates here were provided by St. Michael’s Hospital in Toronto. Certain procedures (i.e., PET scan, CT scan, MRI scan) are paid for, in part, out of the hospital’s global budget; these estimates were provided by The Ottawa Hospital. It is understood that the relative costs of imaging will vary from one institution to the next.

According to our estimates (Table 8), the cost of scintigraphy with ^99mTc-based radioisotopes to establish whether obstruction is present is $310.45. U/S is a minimally less costly alternative. MRU is a moderately more costly imaging test.

Table 8

Cost Estimates Based on the Ontario Schedule of Benefits for Physician Services Under the Health Insurance Act (September 2011).

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APPENDICES