Introduction to Fracture Diagnosis
A bone fracture, commonly known as a broken bone, occurs when stress exerted on a bone exceeds its structural integrity. These breaks are not always straightforward and can arise from various causes, broadly categorized into traumatic fractures, insufficiency fractures, and stress fractures. Each type presents unique diagnostic challenges, making accurate and timely Fracture Diagnosis crucial for effective treatment and recovery.
Traumatic fractures are often the most recognized, resulting from sudden, forceful impacts such as falls, vehicle accidents, or direct blows. In contrast, insufficiency fractures occur in bones weakened by underlying conditions like osteoporosis, where normal weight-bearing stress becomes too much for the compromised bone to handle. Stress fractures, also known as fatigue fractures, develop gradually from repetitive stress on healthy bone, commonly seen in athletes and individuals undergoing intense physical training.
Initial assessment for suspected fractures typically involves plain radiography, or X-rays. X-rays are effective in visualizing most fractures, especially significant breaks. However, they may fall short in detecting subtle fractures, particularly in children whose skeletons are still developing. Stress fractures, especially in their early stages, and occult fractures—those not immediately visible—can also be missed on initial X-rays. When clinical signs of a fracture persist despite a negative X-ray, the possibility of an occult fracture must be considered. Follow-up X-rays can sometimes reveal these hidden fractures as bone loss around the fracture site becomes more pronounced during the natural healing process.
If X-rays remain inconclusive while clinical suspicion of a fracture is high, advanced imaging techniques become necessary. These may include bone scintigraphy (bone scan), Magnetic Resonance Imaging (MRI), or Computed Tomography (CT) scans. These modalities offer different strengths in visualizing bone structures and detecting early signs of fracture, playing a vital role in accurate fracture diagnosis.
This article will delve into the role of bone scintigraphy in fracture diagnosis, comparing it with other diagnostic methods and evaluating its effectiveness based on various criteria relevant to patient care and healthcare systems. While the primary focus is on adults, particularly those with suspected osteoporotic or stress fractures, the discussion will also touch upon the relevance of these diagnostic approaches in pediatric cases where appropriate.
Bone Scintigraphy: A Key Tool in Fracture Diagnosis
Bone scintigraphy, commonly known as a bone scan, is a frequently utilized nuclear medicine procedure for detecting a wide array of bone disorders, including fractures. In Canada, a significant portion of technetium-99m (99mTc), a key radioisotope in nuclear medicine, is used in bone scintigraphy.
The procedure typically involves a three-phase radionuclide examination. Initially, a small amount of 99mTc-labeled radiopharmaceutical, approximately 25 millicurie (mCi), is injected into the patient. The patient is then positioned under a gamma camera, which detects the gamma rays emitted by the radiopharmaceutical. Images are captured in three distinct phases:
- Phase 1: Blood Flow/Dynamic Phase: This phase begins almost immediately after the radiopharmaceutical administration. Images are rapidly acquired over the area of interest to visualize blood flow to the region.
- Phase 2: Blood Pool Phase: Occurring 5 to 10 minutes after the initial phase, this phase captures images as the radiotracer pools in the blood vessels of the bone. Radiotracer uptake in bone is influenced by blood flow and the rate of new bone formation, making this phase critical for assessing vascularity and early bone reaction.
- Phase 3: Delayed Images: These images are taken 1.5 to 5 hours post-injection, depending on the patient’s age and the protocol. This delay allows the radiotracer to clear from soft tissues, enhancing the contrast between bone and background, thus improving bone visualization.
The gamma camera images obtained during bone scintigraphy reflect the activity of osteoblasts, the bone cells responsible for new bone formation. “Cold” spots, areas with minimal or no tracer absorption, may indicate reduced blood supply to the bone, possibly due to bone infarction or certain cancers. Conversely, “hot” spots, areas of increased tracer uptake, signify rapid bone turnover or repair processes, often indicative of fractures, tumors, or infections.
While radiography remains the primary modality for skeletal trauma evaluation, bone scintigraphy plays a complementary role, particularly in cases of occult injuries. It can detect bone changes within hours of an injury, making it invaluable in early fracture diagnosis. This is especially crucial in children under two years old with suspected non-accidental fractures and in identifying occult osteoporotic fractures in adults.
Diagnostic Alternatives to Bone Scintigraphy
When considering fracture diagnosis, bone scintigraphy is not the only option. Several alternative diagnostic tests offer different advantages and are considered based on the clinical scenario and suspected type of fracture. For this discussion, the primary alternatives to bone scintigraphy include:
- X-ray (Radiography): Often the first-line imaging for suspected fractures, readily available and cost-effective for initial assessment.
- Computed Tomography (CT): Provides detailed cross-sectional images of bone, excellent for complex fractures and assessing fracture extent.
- Magnetic Resonance Imaging (MRI): Offers superior soft tissue detail and bone marrow edema sensitivity, highly effective for stress fractures and occult fractures, especially in areas like the scaphoid bone.
- Positron Emission Tomography (PET): Primarily used in oncology, but 18F-PET is emerging in skeletal trauma assessment, offering metabolic activity information.
The selection of the most appropriate diagnostic test depends on various factors, including the suspected fracture type, location, patient’s age, clinical presentation, and the need for detailed bone or soft tissue evaluation. Each modality has its strengths and limitations, which will be further explored in the context of diagnostic accuracy, risks, and accessibility.
Evaluating Diagnostic Tests for Fracture Diagnosis: Key Criteria
To comprehensively evaluate the utility of bone scintigraphy and its alternatives in fracture diagnosis, several key criteria are considered. These criteria help assess the overall impact and suitability of each diagnostic test in clinical practice and healthcare systems. The eleven criteria outlined below provide a structured framework for comparison:
- Size of the Affected Population: The prevalence of conditions requiring fracture diagnosis, such as osteoporotic and stress fractures, influencing the demand for diagnostic services.
- Timeliness and Urgency of Test Results in Planning Patient Management: How quickly test results are needed to guide treatment decisions, especially critical in fracture management to prevent complications.
- Impact of Not Performing a Diagnostic Imaging Test on Mortality Related to the Underlying Condition: The potential increase in mortality risk if a fracture is missed or diagnosis is delayed, particularly relevant in osteoporotic hip fractures.
- Impact of Not Performing a Diagnostic Imaging Test on Morbidity or Quality of Life Related to the Underlying Condition: The consequences of delayed or missed fracture diagnosis on patient morbidity, functional outcomes, and overall quality of life.
- Relative Impact on Health Disparities: Whether access to or utilization of different diagnostic tests contributes to or mitigates health disparities across different population groups.
- Relative Acceptability of the Test to Patients: Patient comfort, anxiety levels, and tolerance of the diagnostic procedure, including factors like radiation exposure, claustrophobia, or injection requirements.
- Relative Diagnostic Accuracy of the Test: The ability of each test to correctly identify fractures (sensitivity) and correctly rule out fractures when they are not present (specificity).
- Relative Risks Associated with the Test: Potential adverse effects of each diagnostic test, including radiation exposure, allergic reactions to contrast agents, or contraindications due to medical implants.
- Relative Availability of Personnel with Expertise and Experience Required for the Test: The availability of trained medical professionals to perform, interpret, and supervise each diagnostic imaging procedure.
- Accessibility of Alternative Tests (Equipment and Wait Times): Geographic availability of imaging equipment, distribution across healthcare facilities, and typical wait times for each type of diagnostic test.
- Relative Cost of the Test: The direct and indirect costs associated with each diagnostic test, including equipment, personnel, consumables, and procedure fees.
These criteria provide a multi-faceted approach to compare bone scintigraphy and its alternatives, considering not only diagnostic performance but also patient-centered outcomes, healthcare system implications, and resource utilization.
Methods for Evaluating Fracture Diagnosis Literature
The evaluation of diagnostic tests for fracture diagnosis relies on a thorough review of published literature. A systematic approach to literature searching is essential to ensure a comprehensive and unbiased assessment. Typically, information specialists employ peer-reviewed search strategies to identify relevant studies.
Key bibliographic databases such as MEDLINE (via Ovid), The Cochrane Library (via Ovid), and PubMed are systematically searched. Search strategies incorporate both controlled vocabulary, like Medical Subject Headings (MeSH), and relevant keywords to capture a broad spectrum of articles related to radionuclide imaging and fracture.
Methodological filters are applied to refine search results, focusing on high-quality evidence such as health technology assessments, systematic reviews, meta-analyses, randomized controlled trials, and diagnostic accuracy studies. Searches are usually limited to English language publications, without publication date restrictions to capture historical context and recent advancements. Regular alerts are set up to keep searches updated with newly published literature.
To broaden the scope beyond commercially published research, grey literature is also explored. This includes searching relevant sections of checklists like the CADTH Grey Matters checklist and using search engines like Google to find web-based materials. Bibliographies of key articles are reviewed to identify additional relevant publications not captured in database searches.
Targeted searches are conducted as needed to gather specific information related to the evaluation criteria. When literature is lacking for certain criteria, expert consultations may be employed to gather insights and perspectives from experienced clinicians and specialists in the field. This multi-pronged approach ensures a robust and well-rounded evidence base for evaluating fracture diagnosis methods.
Literature Search Results: Diagnostic Accuracy in Fracture Diagnosis
The systematic literature search for studies evaluating diagnostic tests for fracture diagnosis yielded a substantial number of citations, which were then screened for relevance and quality. From an initial pool of 785 citations, 44 articles underwent full-text review, and ultimately 29 were included in the final analysis.
The search identified a limited number of high-level evidence sources. No health technology assessments (HTAs) directly comparing bone scintigraphy with other modalities for fracture diagnosis were found. However, two relevant systematic reviews and meta-analyses were identified. One review, found in grey literature, addressed criteria related to timeliness and patient outcomes. The other, focusing on diagnostic accuracy, compared bone scintigraphy with CT and MRI specifically for scaphoid fractures. Notably, no systematic reviews comparing bone scintigraphy with 18F-PET for fracture diagnosis were identified. Six primary studies reporting on diagnostic accuracy were also included in the analysis.
The remaining articles, along with grey literature and sources from reference lists, provided data for the other evaluation criteria beyond diagnostic accuracy. These findings collectively contribute to a comprehensive understanding of the strengths and limitations of bone scintigraphy and its alternatives in fracture diagnosis.
Summary of Criterion Evidence for Fracture Diagnosis
Criterion 1: Size of Affected Population
The population at risk for fractures requiring diagnostic imaging, particularly bone scintigraphy, primarily includes adults with stress fractures and elderly individuals with osteoporosis. Osteoporosis is a major concern due to its weakening effect on bones, making them susceptible to fracture.
Osteoporotic Fracture
Osteoporosis is characterized by reduced bone mass and deterioration of bone tissue, significantly increasing fracture risk. While standard X-rays are often used for initial diagnosis, occult fractures, which are not immediately visible, are estimated to occur in 2% to 9% of osteoporosis patients.
Canada experiences an estimated 138,600 osteoporosis-associated fractures annually. Hip fractures are particularly prevalent among the elderly. In Saskatchewan, for instance, hip fracture rates for those aged 75-84 are 8.5 per 1,000 women and 4.4 per 1,000 men, escalating to 22.5 and 14.1 per 1,000 respectively for individuals over 85.
Stress Fracture
Stress fractures are common injuries among athletes (both professional and recreational), dancers, and military recruits. Track and field athletes exhibit the highest incidence compared to other sports. The lower extremities, including the tibia, metatarsals, and fibula, are most frequently affected, followed by the hip (femoral neck). However, stress fractures can occur in non-weight-bearing bones as well, such as ribs, upper extremities, and the pelvis.
In military settings, calcaneus (heel bone) stress fractures are also prevalent. Risk factors for stress fractures include a history of stress fractures, fitness level, physical activity intensity, and gender. Women are at a higher risk, with a relative risk reported between 1.2 and 10. Tibial fractures are most common in athletes and military recruits, followed by femoral neck and foot fractures.
Stress fractures affect less than 1% of the general population. However, in civilian athletic populations, they account for approximately 10% of injuries. Military recruits report incidence rates from 1% to as high as 31%, depending on training duration and intensity. The significant prevalence of both osteoporotic and stress fractures underscores the substantial population that could benefit from effective fracture diagnosis methods like bone scintigraphy and its alternatives.
Criterion 2: Timeliness and Urgency of Test Results
Prompt fracture diagnosis, particularly of occult or stress fractures, is critical for effective patient management. Failure to diagnose these fractures in a timely manner can lead to severe complications.
Osteoporotic Fracture
In elderly patients, delayed diagnosis of osteoporotic fractures can result in significant long-term disability and increased mortality. Fragility fractures increase the risk of subsequent fractures, emphasizing the need for rapid detection and appropriate treatment to prevent future incidents. Early detection and treatment of hip fractures, in particular, can minimize morbidity and mortality, preventing a rapid decline in quality of life often associated with these injuries.
Expert guidelines unanimously recommend hip fracture correction within 24 hours, barring medical contraindications. Early surgical fixation reduces pain and disability, simplifies surgical procedures, shortens operating room time, and decreases post-operative hospital stays.
Stress Fracture
Delayed diagnosis of high-risk stress fractures can lead to progression to complete fractures, non-union (failure of fracture to heal), delayed union, the necessity for surgical intervention, or refracture. For example, early diagnosis is crucial for tarsal navicular fractures due to their high complication rates. Early recognition of partial fractures in this area can prevent progression to complete fractures. Therefore, timely fracture diagnosis of stress fractures is essential in reducing morbidity and ensuring better patient outcomes.
Criterion 3: Impact on Mortality
The impact of delayed or missed fracture diagnosis on mortality varies depending on the type of fracture, with osteoporotic fractures, especially hip and vertebral fractures, posing a significant risk.
Osteoporotic Fracture
Hip and vertebral fractures significantly increase the risk of death following the fracture event. Osteoporosis Canada reports that up to 30% of hip fractures in osteoporosis patients result in death, with approximately 23% of hip fracture patients dying within a year. While osteoporosis is less common in men, they experience higher post-fracture mortality and institutionalization rates compared to women.
A Canadian study examining the relationship between fractures and mortality followed 7,753 individuals aged 50 and older for five years. The study found that individuals with hip or vertebral fractures were significantly more likely to die during the follow-up period compared to those without fractures. Specifically, vertebral fractures had an adjusted hazard ratio (HR) of 2.7 (95% CI 1.1 to 6.6), and hip fractures had an HR of 3.2 (95% CI 1.4 to 7.4). Fractures of the forearm, wrist, or ribs did not show a significant impact on mortality.
Stress Fracture
In otherwise healthy adults, accidental occult skeletal fractures, particularly stress fractures, are unlikely to directly affect mortality rates. The primary concern with stress fractures is morbidity and functional impairment rather than mortality.
Criterion 4: Impact on Morbidity and Quality of Life
Failure to perform diagnostic imaging for fracture diagnosis, particularly in osteoporotic and stress fractures, significantly impacts patient morbidity and quality of life.
Osteoporotic Fracture
Fractures, especially in the elderly, are associated with substantial morbidity and reduced quality of life. Delays in hip fracture treatment are linked to longer hospital stays and increased complications, including pressure sores, pneumonia, and confusion. Early surgical fixation of hip fractures is crucial for reducing pain, disability, and post-operative complications, leading to shorter hospital stays and better functional outcomes.
Wrist fractures in older women are associated with clinically significant functional decline and reduced quality of life, affecting daily activities like meal preparation and potentially leading to loss of functional independence.
Stress Fracture
If stress fractures are not promptly diagnosed and treated, they can progress to complete fractures, resulting in significant morbidity. Potential complications include delayed union, non-union, need for surgery, refracture, avascular necrosis (bone tissue death due to lack of blood supply), and osteoarthritis. These complications can significantly impede an athlete’s or active individual’s return to their pre-injury activity level and quality of life. Timely fracture diagnosis is therefore essential to minimize these long-term impacts.
Criterion 5: Relative Impact on Health Disparities
Health disparities in fracture diagnosis and care can arise from various factors, although specific data directly linking disparities to the detection of osteoporotic or stress fractures are limited.
Women are at a greater risk for both stress and osteoporosis-induced fractures. Osteoporosis risk, and consequently fracture risk, increases with age across all ethnicities. Wrist fractures are more common in women under 75, while hip fractures become more prevalent in women over 75. Men, although less likely to develop osteoporosis, still account for nearly 30% of hip fracture cases and experience higher post-fracture mortality and institutionalization rates than women.
Studies have shown that certain ethnic groups may face higher risks. For example, a Saskatchewan study indicated that elderly First Nations individuals in Manitoba had nearly double the rate of osteoporotic fractures at all sites compared to age- and sex-matched non-Aboriginal controls, irrespective of diabetes status. This suggests potential disparities in bone health and fracture risk among indigenous populations. Further research is needed to fully understand and address health disparities related to fracture diagnosis and management across diverse populations.
Criterion 6: Relative Acceptability of Tests to Patients
Patient acceptability varies among different diagnostic tests for fracture diagnosis, primarily based on factors like radiation exposure, comfort during the procedure, and potential anxiety or discomfort.
Bone Scintigraphy
Limited data is available on patient-specific acceptability of bone scintigraphy. Studies suggest that any medical test, including bone scans, can cause psychological stress in children and their parents, particularly in the context of serious conditions like osteosarcoma. Patients may have concerns about radiation exposure from the radiopharmaceutical injection and the intravenous procedure itself.
CT
CT scans also raise concerns about radiation exposure. Additionally, some patients may experience claustrophobia within the CT scanner. Newer CT scanners may mitigate this issue to some extent. Holding breath for extended periods during the scan can also be uncomfortable or challenging for some patients.
MRI
MRI is known to induce claustrophobia in some individuals due to the enclosed space, and the loud noises during the scan can be bothersome. Newer MRI machines may offer more open designs, potentially reducing claustrophobic reactions. Approximately 30% of patients may experience apprehension, and 5% to 10% might endure significant psychological distress, panic, or claustrophobia during MRI. Remaining still for the duration of the scan can also be difficult for some patients. However, MRI has the advantage of no ionizing radiation, which is preferable for some patients.
PET
Similar to bone scintigraphy and CT, PET scans involve radiation exposure and require intravenous injection of a radiopharmaceutical agent, which may raise patient concerns about radiation risks and injection discomfort.
Criterion 7: Relative Diagnostic Accuracy
Diagnostic accuracy is a critical factor in evaluating the effectiveness of different imaging modalities for fracture diagnosis. Several studies have compared bone scintigraphy with alternative tests like CT, MRI, and PET.
Systematic Reviews
Bone Scintigraphy vs. CT
A 2010 systematic review and meta-analysis compared bone scintigraphy, MRI, and CT for diagnosing suspected scaphoid fractures. Analyzing 26 studies, the review found no significant difference in the diagnostic odds ratio (DOR) between CT and bone scintigraphy, suggesting comparable overall diagnostic performance. However, CT showed higher positive and negative likelihood ratios (LR+ 93, LR- 0.07) compared to bone scintigraphy (LR+ 8.82, LR- 0.03). Generally, LR+ > 10 and LR- < 0.1 are considered strong evidence to rule in or rule out diagnoses. The authors concluded that more research is needed to definitively assess CT’s diagnostic performance relative to bone scintigraphy for scaphoid fractures.
Bone Scintigraphy vs. MRI
The same systematic review also compared bone scintigraphy and MRI for scaphoid fracture diagnosis. Both modalities showed equally high sensitivity and diagnostic value for excluding scaphoid fractures. However, MRI demonstrated higher specificity and was considered better for confirming scaphoid fractures. MRI’s positive likelihood ratio was > 90 (specifically 96), and its negative likelihood ratio was < 0.1 (specifically 0.04).
A 2005 “shortcut review” of four studies comparing MRI and bone scintigraphy for occult scaphoid fractures concluded that MRI was slightly superior to bone scintigraphy in diagnostic accuracy. MRI also offered the advantage of detecting clinically significant soft tissue injuries often missed by bone scintigraphy. Additionally, MRI was faster to perform. The review suggested MRI as the preferred investigation for suspected scaphoid fractures after negative initial and follow-up X-rays, with bone scintigraphy as a reasonable alternative for claustrophobic patients.
Primary Studies
Bone Scintigraphy vs. Multiple Alternatives
A prospective study comparing MRI, CT, and bone scintigraphy in athletes with suspected tibial stress injuries found MRI to have the highest sensitivity (88%) compared to bone scintigraphy (74%) and CT (42%). MRI also demonstrated superior specificity, accuracy, and predictive values in detecting early tibial stress injuries.
Bone Scintigraphy vs. CT
A prospective study comparing 16-detector CT with bone scintigraphy for suspected stress fractures found bone scintigraphy identified more cases (13 out of 33) than CT (4 out of 33). CT demonstrated better detail of bone cortex and trabecular structure but was less sensitive for stress fracture detection. The study concluded that multi-section CT is not recommended as a first-line tool for stress fractures and should be reserved for specific situations, such as when bone scintigraphy results are uncertain or to rule out other diagnoses.
Bone Scintigraphy vs. MRI
Several primary studies compared bone scintigraphy and MRI for various fracture types. One prospective study in patients with suspected bone stress injuries found that while both scintigraphy and MRI detected stress injuries after negative X-rays, MRI provided more detailed diagnostic information, including fracture lines and periosteal edema. The authors recommended MRI as less invasive and more informative for initial diagnosis of suspected bone stress injuries.
A retrospective study comparing radiography and MRI to bone scintigraphy (considered the gold standard) in military trainees with stress-related pain found MRI to be more sensitive (100%) and accurate (95%) than bone scintigraphy (accuracy not explicitly stated but lower than MRI’s). Radiography had significantly lower sensitivity (56%) and accuracy (67%). The study suggested MRI should be the standard reference technique for assessing bone stress injuries.
Another study comparing MRI and bone scintigraphy in patients with normal X-rays but scintigraphy results suggestive of stress-related bone injuries reported bone scintigraphy correctly identified all normal and abnormal findings. However, MRI showed variable accuracy depending on the reader, with sensitivity ranging from 63% to 69%. The authors suggested bone scintigraphy as the initial imaging modality for suspected stress-related injuries when the likelihood of other bone diseases is low.
In a study comparing MRI and bone scintigraphy for hip pain in endurance athletes, MRI was found to be superior to bone scintigraphy in differentiating causes of hip pain, with 100% accuracy compared to 68% for bone scintigraphy in detecting femoral neck stress fractures.
Bone Scintigraphy vs. PET
While 18F-PET is increasingly used for skeletal trauma evaluation, no studies directly comparing its diagnostic accuracy to bone scintigraphy for fracture diagnosis were identified in the literature search.
Criterion 8: Relative Risks Associated with Tests
Each diagnostic test for fracture diagnosis carries potential risks, which can be broadly categorized into radiation-related and non-radiation-related risks.
Non-Radiation Risks
Bone Scintigraphy
Bone scintigraphy is generally considered safe, but mild adverse reactions to 99mTc-labeled tracers have been reported in some studies, including skin reactions. Allergic reactions are rare but possible.
CT
CT scans using contrast agents may cause allergic reactions, which can worsen with repeated exposure. Mild side effects from contrast agents, such as nausea, vomiting, or hives, are also possible. Severe reactions are rare. CT contrast is contraindicated in patients with elevated heart rate, hypercalcemia, and impaired renal function. Gadolinium (Gd)-based contrast agents are contraindicated in patients with renal failure due to the risk of nephrogenic systemic fibrosis.
MRI
MRI is contraindicated in patients with metallic implants, including pacemakers. Gadolinium contrast agents used in MRI can also cause allergic reactions, though severe reactions are rare. Side effects may include headaches, nausea, and metallic taste. Similar to CT contrast, Gd-based agents are contraindicated in patients with renal failure due to nephrogenic systemic fibrosis risk.
PET
PET scans involve radiopharmaceuticals, and while adverse reactions are rare, concerns about injection and potential allergic reactions exist. A large prospective evaluation of PET scans reported no adverse reactions in over 33,000 scans.
Radiation Risks
Bone scintigraphy and PET expose patients to ionizing radiation. CT also involves radiation, whereas MRI does not. Table 3 provides effective radiation doses for these procedures. It’s important to note that the PET dose estimate in the table may be higher than for a single-site scan.
Criterion 9: Relative Availability of Personnel
The availability of trained personnel is crucial for the effective delivery of diagnostic services for fracture diagnosis. Each imaging modality requires specific expertise.
Bone Scintigraphy
In Canada, bone scintigraphy procedures must be performed, supervised, and interpreted by nuclear medicine physicians or diagnostic radiologists with specialized training in nuclear imaging. Physicians should hold certifications from the Royal College of Physicians and Surgeons of Canada or the Collège des médecins du Québec. Nuclear medicine technologists certified by the Canadian Association of Medical Radiation Technologists (CAMRT) are required to conduct bone scans.
All Alternative Imaging Modalities
Diagnostic CT scans, MRI, and PET scans also require supervision and interpretation by certified diagnostic radiologists or nuclear medicine physicians. Medical radiation technologists (MRTs) certified by CAMRT or equivalent bodies are necessary for performing these scans. Service engineers are essential for equipment installation, calibration, and maintenance. Qualified medical physicists are needed for equipment testing and ongoing quality control.
CT and MRI
Specifically for CT and MRI, MRTs must have CAMRT certification in radiography or magnetic resonance, respectively, or equivalent certifications. Training for CT technologists should meet national and provincial specialty qualifications.
PET
PET scans require nuclear medicine physicians or diagnostic radiologists with nuclear imaging expertise for supervision and interpretation. Technologists must be CAMRT certified or hold equivalent credentials. The availability of trained personnel, especially in specialized areas like nuclear medicine and radiology, can influence access to these diagnostic services, particularly in remote or underserved regions.
Criterion 10: Accessibility of Alternative Tests (Equipment and Wait Times)
Accessibility to diagnostic imaging equipment varies across Canada, affecting wait times and patient access to fracture diagnosis services.
Bone Scintigraphy
Bone scintigraphy requires nuclear medicine facilities with gamma cameras, including SPECT (Single-Photon Emission Computed Tomography) capabilities. However, three Canadian territories—Yukon, Northwest Territories, and Nunavut—lack nuclear medicine equipment entirely, limiting access in these regions.
CT
CT scanners are more widely available than nuclear medicine equipment but are still absent in Nunavut. Average weekly CT scanner usage in Canada varies by province, with a national average of 60 hours per week. In 2010, the average wait time for a CT scan in Canada was 4.2 weeks.
MRI
MRI scanners are not available in Yukon, Northwest Territories, or Nunavut. Average weekly MRI scanner usage nationally was 71 hours in 2006-2007, ranging from 40 hours in Prince Edward Island to 99 hours in Ontario. The average wait time for MRI in Canada in 2010 was significantly longer than for CT, at 9.8 weeks.
PET
PET scan availability is more limited, with approximately 31 centers equipped to perform PET scans across Canada in 2010, primarily located in British Columbia, Alberta, Manitoba, Ontario, Quebec, New Brunswick, and Nova Scotia. There were 36 PET or PET/CT scanners, with some dedicated to research. The limited geographic distribution of PET facilities impacts accessibility, especially for patients in provinces with fewer centers or in rural areas.
These variations in equipment availability and utilization, coupled with differing wait times, highlight significant accessibility challenges for various fracture diagnosis modalities across Canada.
Criterion 11: Relative Cost of Tests
The cost of diagnostic tests is a crucial consideration for healthcare systems. Relative costs for bone scintigraphy and its alternatives can be estimated using fee schedules and hospital cost data.
Based on Ontario’s Schedule of Benefits, the estimated cost for a bone scan using 99mTc-based radioisotopes is approximately $335.55. CT and MRI are slightly more expensive alternatives, while 18F-PET is significantly more costly. These cost estimates include technical fees (covering radiopharmaceuticals, supplies, and non-physician salaries) and maintenance fees. Costs for PET, CT, and MRI may be partially covered under hospital global budgets.
It’s important to note that these are relative cost estimates and may vary between institutions and provinces. However, they provide a general comparison of the economic implications of using different diagnostic modalities for fracture diagnosis. Bone scintigraphy generally presents itself as a cost-effective option compared to MRI and particularly PET, while offering valuable diagnostic information in many clinical scenarios.
Conclusion: Optimizing Fracture Diagnosis Strategies
Accurate and timely fracture diagnosis is paramount for effective patient care and management of bone injuries. Bone scintigraphy plays a significant role in this diagnostic landscape, particularly for detecting occult and stress fractures, and in evaluating osteoporotic fractures. While radiography remains the initial imaging modality, bone scintigraphy, MRI, CT, and PET offer complementary strengths in specific clinical situations.
MRI often excels in sensitivity and soft tissue detail, making it highly effective for stress fractures and occult scaphoid fractures. CT provides detailed bone structure visualization, beneficial for complex fractures. PET, though less frequently used in routine fracture diagnosis, is emerging as a valuable tool, especially in specialized cases.
When choosing between these modalities, a multifaceted approach is necessary, considering diagnostic accuracy, timeliness, patient acceptability, radiation risks, equipment availability, personnel expertise, and cost. Bone scintigraphy stands out as a cost-effective and widely available option with good sensitivity for detecting bone activity related to fractures. However, MRI and CT may be preferred in specific scenarios requiring higher specificity or detailed anatomical information.
Healthcare providers must weigh these factors to optimize fracture diagnosis strategies, ensuring timely and accurate identification of bone injuries while considering patient safety, comfort, and healthcare resource utilization. Future research should focus on direct comparative studies, particularly between bone scintigraphy and newer modalities like 18F-PET, to further refine diagnostic algorithms and improve patient outcomes in fracture management.
