Ordering of Diagnostic Imaging by Physical Therapists: A 5-Year Retrospective Practice Analysis

Aaron P Keil, Brian Baranyi, Sameer Mehta, Amma Maurer, Ordering of Diagnostic Imaging by Physical Therapists: A 5-Year Retrospective Practice Analysis, Physical Therapy, Volume 99, Issue 8, August 2019, Pages 1020–1026, https://doi.org/10.1093/ptj/pzz015

Abstract

Significant progress has been made in implementing direct access. As more therapists transition into direct access roles, it seems prudent to consider how additional resources common to other first-contact providers might impact patient care.

Direct referral for diagnostic imaging by physical therapists is relatively rare in the civilian setting and little has been published on the subject. The primary objective of this study was to examine the appropriateness of diagnostic imaging studies referred by civilian physical therapists at an academic medical center. Secondary objectives were to track reimbursement data and overall use rates.

This was a single-center, retrospective practice analysis of 10 physical therapists over a period of nearly 5 years.

The electronic medical record was reviewed for each patient who had an imaging referral placed by a physical therapist. Relevant clinical exam findings and patient history were provided to a radiologist who then applied the American College of Radiology Appropriateness Criteria to determine appropriateness. Reimbursement data and therapist use rates were also evaluated.

Of the 108 total imaging studies, 91% were considered appropriate. Overall, use rates per direct access evaluation were 9% for plain film x-rays and 4% for advanced imaging. Reimbursement was 100%.

This study was limited to 10 physical therapists at 1 practice location. Appropriateness was evaluated by 1 radiologist. The educational background of referring therapists was not evaluated.

Physical therapists demonstrated appropriate use of diagnostic imaging in the vast majority of cases (91%). They were judicious in their use of imaging, and there were no issues with reimbursement. These findings could be useful for physical therapists interested in acquiring diagnostic imaging referral privileges.

The physical therapist as a first point of contact in the health care system has become increasingly common in recent years. Virtually every US state and the District of Columbia now has some form of direct access provision for physical therapy services. 1 Various health care networks are now placing physical therapists at the entry point of care for patients experiencing musculoskeletal conditions, and some hospitals now use physical therapists in the Emergency Department to triage patients with orthopedic injuries. 2–5

As our profession continues to advocate for physical therapists functioning as first-contact providers, it seems prudent to consider what additional resources are routinely available to other first-contact providers (ie, ordering of labs, referral for imaging) as we seek to further optimize patient care.

The use of diagnostic imaging by physical therapists is currently common practice in several countries including Australia, Canada, the United Kingdom, the Netherlands, Norway, and South Africa. 6 Physical therapists in the US military have held privileges to refer for imaging studies directly for decades. 7–13 This could be a contributing factor for the documented success of the military in maintaining patient safety in a direct access environment. One study of over 50,000 patients seen by military physical therapists in direct access encounters reported no adverse events or malpractice litigation of any kind against physical therapists. 14

As more civilian therapists seek to step into direct access roles, it is worthwhile to explore the resources used in successful long-standing direct access models such as those used in the military and in other countries. 7–14 One key difference in resource availability could be the ability to refer for imaging studies directly.

In recent years, the physical therapy profession has placed greater focus on exploring the role of diagnostic imaging referral privileges in physical therapist practice. 6, 15–20 Physical therapy program accreditation standards now include specific criteria related to diagnostic imaging. 21 Some state-led initiatives have resulted in practice acts either being updated or interpreted to allow physical therapists to refer for imaging studies directly. 17, 18 Additionally, the American Physical Therapy Association has been charged by its members to pursue practice authority related to imaging. 6

As our profession seeks to incorporate imaging into physical therapist practice, we should be mindful of the ever-present danger of overuse of imaging. In 2010, nearly 100 billion dollars was spent on medical imaging alone. 22 The inappropriate referral for diagnostic imaging by physicians for low back pain has been identified as among the top 5 areas to address that would have the greatest impact on improved care and reduced cost. 23 One review of over 500 advanced imaging studies referred for by primary care physicians concluded that 26% of the referrals were considered inappropriate. 22 As a result, efforts have been made to provide best practice recommendations related to the referral for diagnostic imaging. For example, current best practice would advise that imaging for patients who have mechanical low back pain is not indicated within the first 6 weeks unless signs and symptoms are consistent with a nonmusculoskeletal cause (ie, a systemic or visceral origin). 23

Research evaluating appropriate use of diagnostic imaging specifically by physical therapists is limited but promising. One study in the United Kingdom of over 3700 patient visits provided by advanced practice physiotherapists with imaging referral privileges revealed referral rates of 13% for plain films and 10% for magnetic resonance imaging (MRI). 14 To our knowledge, there has been only 1 study in the United States that has evaluated appropriateness and use of diagnostic imaging referrals placed by physical therapists. 9 This study of military physical therapists demonstrated favorable results in both referral criteria as well as overall use rate when compared with other health care providers. No study to date has evaluated the use of diagnostic imaging by US civilian physical therapists with privileges to refer for studies directly.

The primary purpose of this study was to evaluate appropriateness of diagnostic imaging referrals placed by US civilian physical therapists functioning in direct access roles at an academic medical center in Washington, DC. Secondary purposes were to describe overall use rates and to evaluate reimbursement for imaging tests when referred by a physical therapist.

Methods

This single-center retrospective study took place in the physical medicine and rehabilitation department at Medstar Georgetown University Hospital in Washington, DC. This setting primarily sees patients with orthopedic conditions; however, patients with neurological, medical, and cardiopulmonary conditions are treated as well. Physical therapists who have completed required competencies, outlined previously, 18 have direct access and unrestricted diagnostic imaging referral privileges at Medstar Georgetown University Hospital. These competencies include continuing education in medical screening and diagnostic imaging (14 contact hours each), a minimum of 2 hours shadowing a musculoskeletal radiologist, review of several articles relevant to direct access care, and a discussion of 2–3 case vignettes with senior staff.

Referral for imaging privileges began in January 2012. Ten different physical therapists had placed diagnostic imaging referrals for patients at the time of this study. Years of experience ranged from 7 to 20 (average = 13). Two therapists had a bachelor's degree in physical therapy (BSPT), 2 had a master's degree (MSPT), and 6 had a clinical doctorate degree (DPT). All 10 therapists were board-certified clinical specialists through the American Physical Therapy Association in either orthopedics or sports physical therapy.

Records for imaging referrals placed by physical therapists were searched from January 2012 to September 2016. Eighty-eight patients had diagnostic imaging referrals placed by a physical therapist for a total of 108 images. There were 39 advanced images (MRI scans/magnetic resonance [MR] arthrograms and computed tomography [CT] scans) and 69 radiographs. The electronic medical record of each patient with an imaging referral placed by a physical therapist was reviewed by the same physical therapist. Pertinent information was deidentified and extracted as it related to the management of each patient. Physical therapy notes from the date of imaging referral plus the imaging referral itself were reviewed to obtain information regarding the rationale for imaging referral. If this was unclear, additional review of the electronic medical record was conducted to compile relevant information. Additional notes were reviewed after imaging was performed to categorize how physical therapy management changed as a result of imaging. These categories are outlined below.

Pertinent patient history, including relevant signs and symptoms, was provided to a board-certified, musculoskeletal fellowship-trained radiologist with 4 years of experience to determine the appropriateness of imaging referrals placed by physical therapists. This radiologist was blinded to patient and therapist identity and to patient outcome. The radiologist identified referrals as “appropriate” or “inappropriate” according to the American College of Radiology (ACR) Appropriateness Criteria. The ACR Appropriateness Criteria are evidence-based guidelines to assist referring providers in making the most appropriate imaging decisions for specific conditions. These guidelines, developed and reviewed annually, assist in improving quality of care and ensuring the proper use of diagnostic imaging studies. The ACR guidelines describe the level of appropriateness for an imaging study by the terminology “usually appropriate,” “may be appropriate,” and “usually not appropriate.” For this study, “usually appropriate” studies were considered to be appropriate use of imaging. This is consistent with the methods reported by Crowell and colleagues, and this rating indicates that the imaging procedure is indicated in the specified scenario at a favorable risk-benefit ratio for patients. 9

Results

Imaging Metrics

From January 2012 to September 2016, 88 patients received referrals for 108 images. There were 69 radiographs and 39 advanced imaging studies (35 MRI scans, 1 MR arthrogram, and 3 CT scans). Some patients had referrals for images for different conditions across different episodes of care, and some patients had multiple referrals for images of the same condition. For example, repeat radiographs or follow-up MRI scans were referred for patients with a high suspicion of pathology that did not appear on initial imaging.

Most radiography referrals were for the hip/pelvis (33%) and ankle/foot (16%), whereas the lumbar spine was the body region most commonly imaged with MRI (36%). Table 1 has a full breakdown of the number and types of imaging referrals.

Number and Type of Imaging Referrals a