The ethereal “efficiency of scale”

By Stuart E. Mirvis, MD, FACR, University of Maryland School of Medicine, Baltimore, MD
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Dr. Mirvis is the Editor-in-Chief of this journal and a Professor of Radiology, Diagnostic Imaging Department, University of Maryland School of Medicine, Baltimore, MD.

By now most radiologists are familiar with the Medicare Physician Fee Schedule Proposed Rule (CMS-1524-P) for 2012.1 In essence,this legislation applies a multiple procedure payment reduction (MPPR) to the professional component of advanced diagnostic imaging services administered to the same patient, by the same physician, during the same session. Radiologists involved in the care of patients with severe injuries and other life-threatening diseases should be especially concerned by this proposal. In the normal course of imaging these patients, it is often medically necessary to perform multiple examinations or repeat examinations over brief time periods, as these are typically patients with complex, multiple, and rapidly evolving medical problems. The imposition of this MPPR policy on the professional component of diagnostic imaging services could profoundly affect the delivery of appropriate and standard-of-care imaging. This legislation either mandates how patients should be cared for or negates the value of the service that radiologists render. The official American College of Radiology (ACR) opinion on the proposed rule concludes that the “[h]ardest hit by the MPPR-PC are practices that serve trauma and cancer centers with estimated Medicare payment reductions in the 7% to 8% range.”2 There are many hospitals, especially tertiary care centers, where the negative financial impact of this legislation would be far greater. Overall, the rationale for this proposal is without merit.

It appears that the CMS decision to apply a MPPR to the professional component of diagnostic imaging services is rooted in the incorrect assumption that there are considerable efficiencies of scale when radiologists interpret successive imaging studies during a single patient visit. Unfortunately, CMS fails to recognize that radiologists are morally and professionally obligated to expend an equal amount of time, effort, and skill on interpreting images, irrespective of whether or not previous examinations have been performed on the same day, using the same modality or further evaluating the same body region as a recent prior examination. Some common settings where patients will require multiple examinations on the same day include severe trauma, cancer diagnosis and follow-up, and stroke. Trauma patients often have multisystem injuries that require imaging of multiple body areas. Many of these patients have depressed levels of responsiveness due to injury or drugs/alcohol making physical examination and history unreliable at best. Computed tomography (CT) detects almost all significant injuries in most patients and excludes such injuries with 98% negative predictive value.3

Given this well-established concept, CT has become the standard of imaging evaluation in traumatized patients. It saves significant time, provides far greater accuracy compared to plain radiographic evaluation, is far less invasive, costly, and time consuming than catheter angiography, a method once heavily used in diagnosis of traumatic injury. Angiography performed by CT has virtually replaced catheter angiography as a diagnostic technique and has considerably focused the use of angiography on those patients who absolutely require catheter-guided treatment for control of bleeding.

An article in the Lancet defends the value of providing multiple imaging procedures to the same patient during a single session.4 This study clearly illustrates that trauma patients with multiple injuries who receive a whole-body CT scan have a much greater probability of survival in comparison to a similar group of patients who had only a single CT examination of part of the body. Expanded use of whole-body CT examinations also helps treat patients more quickly and accurately. This technology has made it far easier to provide multiple procedures to a single patient during a single imaging session, which has translated to more efficient care and frees available beds, allowing admission of other severely injured patients. Unfortunately, the changes proposed by CMS through this reimbursement policy will stymie the use of this highly accurate and efficient diagnostic procedure as currently practiced in most centers admitting major trauma patients.

For the sake of argument, let’s assume that these comments regarding the value of whole-body CT are scientifically well established, that CT quickly detects significant injuries, improves treatment selection and the patient’s ultimate health outcome. Let us further assume that this CT method saves money by not requiring other less efficient imaging studies, prevents unneeded surgery (exploratory), and shortens hospitalization time. Undoubtedly, whole-body CT saves lives and decreases overall patient morbidity.

Well, what about paying for the professional interpretation of this study? Is this a single examination? Does a radiologist require the same amount of time to interpret a chest CT or a head CT as a whole-body CT? Let’s imagine that this whole-body CT is divided up into different body regions (head, cervical spine, chest, abdomen/pelvis, thoracic, and lumbar spine). Images of each body region are sent to four specialists in a radiology department (thoracic, abdominal, neuroradiology, musculo-skeletal radiologists), and each applies his or her high level of expertise and experience to interpret the images of this particular body area. How much time would be required in the aggregate for each radiologist to do his or her job properly? How much specialty training and diagnostic expertise do they bring to the interpretation of images from each body part? Would the CT study of each individual body area be assumed to be the same study interpreted by 4 different radiologists? The images are acquired in a single scan and thus far more quickly for the patient and with less x-ray exposure than needed for individual studies of multiple body areas due to the great technology available. But isn’t the professional interpretation of separate body regions a unique study tailored to each radiologist’s area of special training? An individual radiologist needs to review each body area as carefully as if they were assessing single body regions acquired at different times. These radiologists are penalized for the advances in CT technology that allow many body regions to be studied at one setting. Should the neuroradiologist receive a full professional fee for his interpretation of the head CT, but the thoracic radiologist half of that for the chest interpretation and so on down the line?

The radiologists in our Emergency Radiology section, who do interpret all individual body parts acquired during one scan, have specialized training and experience. The whole-body CT scan obtained in the typical polytrauma patient requires a review of 600 to 1,200 or more images. Each body region is reviewed independently and in succession. Other studies that can be obtained and separately reviewed include CT of the face, temporal bones, and extremities. Interpretation of each of these studies would be a unique study in almost any other setting,but not in the trauma patient. Each body region studied that comprises a single-billed “scan” needs to be obtained and interpreted contemporaneously with the others in order for the radiologist to give a “holistic,” comprehensive report soon after the CT study is completed—when it will do the most good to guide patient care. This is far more efficient and valuable than having multiple separate reports from several different radiologists.

The 2012 Medicare Physician Fee Schedule Proposed Rule (CMS-1524-P) penalizes the radiologist working in this fashion for the technical improvements in CT. It also penalizes the radiologist for providing comprehensive and efficient care by identifying all injuries at one time, and thus preventing any need, risk, expense, and labor incurred in returning to the scanner or pursuing other imaging examinations.The interpretation of this large study of many body regions is both time and labor intensive. There is no efficiency of scale created in the effort needed to provide careful interpretation of these numerous images through the entire body.

Furthermore, not reimbursing the interpretation of a repeated imaging study in the same 24-hour period in a trauma or critical care setting fails completely to recognize appropriate medical care. An obvious example is the patient who undergoes brain surgery and 6 hours later has an unexpected deterioration of mental status and now absolutely needs another emergency head CT repeated to look for any changes requiring additional or altered treatment. Should the interpretation for the emergency head scan be performed gratis because of the patient’s deteriorating status or severity of illness? Would the patient not want that CT study performed and interpreted as quickly as possible by the most appropriate specialist? Failure to accept this completely medically justified need for an early repeat head scan as legitimate and worthy of full professional reimbursement for timely interpretation is equivalent to denying this patient the study.

Of course, trauma and emergency radiology care is certainly not the only segment of radiology practice that would be adversely affected by the proposed MPPR, as illustrated in the following clinical scenarios.

  1. In cancer patients who present with suspected acute malignant spinal cord it is standard to perform magnetic resonance imaging (MRI)exams of the cervical, thoracic, and lumbar spine given that those patients have a high incidence of other malignant spinal lesions requiring emergent or urgent treatment.
  2. Patients who present with symptoms of acute cerebral infarction may benefit from blood-clot disrupting treatment. In this setting it is the standard of care to perform either a combination of CT scans (a noncontrast head CT, CT-brain perfusion study, CT angiogram of head, and CT angiogram of neck) or a combination of MRI’s (brain MRI, brain-MR angiogram, and neck-MR angiogram) in order to confirm or exclude stroke and to determine if clot lysis therapy is warranted and safe.
  3. Patients with suspected acute aortic dissection frequently require CT angiograms of the chest and abdomen. If involvement of aorta branch vessels is suspected, CT angiograms of the neck, pelvis, and/or extremities are frequently also needed to determine the full extent of the abnormality.
  4. Patients undergoing immediate neurosurgical intervention for emergent conditions routinely require multiple imaging studies during one 24-hour period. For example, a patient who presents to the emergency department with life threatening hydrocephalus due to cerebrospinal fluid (CSF) flow blockage by either a tumor or hemorrhage typically requires placement of a ventricular shunt to alleviate intracranial pressure. As a result, the patient would not only require an initial CT scan to diagnose the blockage but would also require at least one CT scan after the procedure to ensure that the catheter was appropriately positioned and did not cause complications, such as additional hemorrhage.

There are many other similar examples. CMS-1524-P penalizes radiologists caring for complex and often extremely ill patients who by medical standards of care “require” multiple imaging studies, studies of multiple anatomic regions, or early repetition of the same study to adequately monitor their medical status and the need for further or altered treatment. The proposal assumes a new efficiency of care that simply does not exist and could potentially drive changes that adversely affect patients.

Stuart E. Mirvis, MD, FACR

Dr. Mirvis wishes to acknowledge the assistance of Dr. Kathirkamanathan Shanmuganathan and Dr. Clint W. Sliker in the preparation of this editorial.


  1. Medicare program payment policies under the physician fee schedule and other revisions to Part B for CY 2012. Centers for Medicare & Medicaid Services. https://www.cms. gov/PQRS/Downloads/2012_NPRM_PFS_Proposed_Rule508.pdf. 140-143. Accessed September 19, 2011.
  2. ACR to CMS: Remove professional component MPPR from Medicare rule. American College of Radiology. Accessed September 19, 2011.
  3. Huber-Wagner S, Lefering R, Qvick LM, et al. Effect of whole-body CT during trauma resuscitation on survival: A retrospective, multicentre study. The Lancet. 2009;25:14551461.
  4. Livingston DH, Lavery RF, Passannante MR, et al. Admission or observation is not necessary after a negative abdominal computed tomographic scan in patients with suspected blunt abdominal trauma: Results of a prospective, multi-institutional trial. J Trauma. 1998;44:273-80; discussion 280-282.
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The ethereal “efficiency of scale”.  Appl Radiol. 

September 30, 2011

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