Common Sense

The CT Scan

Marc D. Haber, MD FAAEM
Past President, Young Physicians Section
Assistant Professor of Emergency Medicine
Tufts University School of Medicine/Baystate Medical Center

The Computerized Tomography (CT) Scan, perhaps like nothing else in our emergency departments, has significantly changed how we practice medicine. I personally trained immediately prior to the advent of widespread multi-slice detector use. Physicians who recently graduated, especially those in affluent or highly funded facilities, may have never had the pleasure of needing to place your potential C-Spine injured patient into a prone position in order to adequately obtain facial bones images. Furthermore, any patient with a respiratory rate greater than apneic always seemed to have significant “respiration artifact” limiting the results. The modern CT scan, including CT angiography, provides fast and amazing resolution of patients’ underlying anatomy and pathologies.

The CT scan certainly has revolutionized the way we care for many patients. For example, lower risk abdominal pain patients with a negative scan are often sent home with routine follow-up. It is cost effective in many circumstances and well-studied.1 Due to these factors, the CT scan is now a widespread and often used tool in the emergency physician’s arsenal. While many clinical decision rules exist, there is always the physician gestalt “out” which allows physicians to lean towards scanning. Often appropriate, but perhaps just as often, the test is ordered due to some combination of self-doubt, consultant desire and/or concern that the patient desires a CT scan.

X-rays have great value outside of the abdomen. But when looking at the abdomen, seldom is the abdominal X-ray diagnostic, more often only suggestive. The MRI has its utility in ruling out appendicitis in the pregnant patient with abdominal pain, but is difficult to obtain in community hospitals.2 Abdominal sonography is more useful than CT scanning in the diagnosis of uncomplicated cholecystitis, but when the clinical presentation is confusing either by history or physical exam, CT imaging may retrospectively be more valuable.3 For all the promise of ED-based focused ultrasonography, the CT scan remains king of emergency abdominal imaging.

Yet CT scans have known risks - risks in which we are well-versed. Occasionally, we directly witness contrast allergy, aspiration of oral contrast, and the traumatic and avoidable “Code Blue” in the scanner. Sometimes we see contrast induced nephropathy (CIN), but that typically is a ward-based diagnosis. The majority of outpatients with CIN likely go unnoticed and self-resolve. What we never see, or so we thought, was the occurrence of malignancy attributable to CT imaging. We all know of the ionizing radiation risks of most forms of radiographic imaging, but the impact of our imaging studies has just recently been quantified. And the results are frightening.

In a recent Archives of Internal Medicine study, 57 million at-risk Americans already on the case4 are estimated to have been scanned in 2007.5 Twenty percent were 34 years of age or younger. 60% of those scanned were female. 29,000 cancers are estimated to have developed out of those studies. CT angiograms of the chest, abdomen and “whole body” have the highest risk of cancer per scan, but due to its large number scanned, 48% of CT related cancers are attributable to abdominal and pelvic imaging.

According to the U.S. Department of Health and Human Services, there were 119 million visits to our emergency departments in 2006. Of these visits, abdominal pain, followed by chest pain, is the most common chief complaint of those between 18 and 44 years of age. These two complaints reverse places for those 45 years and older.6 It goes without saying that the decision to utilize a CT scan in the work-up of an individual with abdominal or chest pain rests in the hands of the ordering physician. That said, often, our hands are pushed, if not forced outright. How many of us have surgical departments whose surgeons will only see the patient “after the CT scan?” How many have been pressured to see more patients per hour or “move the meat” often leading to us putting the CT scan much earlier in the work-up? Who hasn’t started providing a patient oral contrast immediately after the physical exam “just in case?” The CT scan may defer a patient’s disposition to either later in the shift or to the radiologist, the consultant, a post sign-out colleague. In doing so, our shifts might become slightly less burdensome, help avoid confrontation, or reduce the anxieties and risks of making a wrong diagnosis. Yet this concept certainly was not taught in our emergency training programs; at least not overtly.

Additionally, the CT scan has gotten so fast that it often takes more time for the technologist to enter patient information into the computer than it does to actually perform the scan. Anecdotally, we have all seen patients who ought to be in either the OR or ICU brought to the scanner for a “quick” scan prior to reaching their appropriate destination. Furthermore, cost-controlling measures may push us towards the scan as well. Health insurance companies may prefer to pay for a CT scan rather than a short hospital admission for serial abdominal exams. They may, for example, nudge hospitals, and therefore providers, towards CT guided disposition by increasing reimbursements for imaging and reducing payments for observational inpatient care and revisits. Furthermore, patients, who also are just as busy with life, might prefer the quicker route to an answer. Overall, the CT scan has the potential to make everyone’s lives easier. By the CT scan’s ability to hasten a disposition, physicians can see more patients, earn more RVUs, and avoid consultant confrontations, and the patient can wait less time on an uncomfortable gurney for a potential diagnosis.

It follows, if abdominal and chest pain are the two most common chief complaints of an ever-increasing volume of ED patients, and the CT scan may make our lives easier during a shift, then more and more patients will be receiving a CT scan, perhaps unnecessarily. Perhaps the Press-Ganey’s will rise, as the patient started the contrast at triage and happily departs quicker. Perhaps our reimbursement rates will rise, because our work RVUs have likewise risen. Perhaps we leave the shift with slightly more certainty of a patient that we treated in the ED. But perhaps we took the easy way out. Perhaps we inadvertently took the less ethical option. Perhaps we exposed our patients to unnecessary and harmful ionizing radiation. Perhaps we added to the 29,000 patients who developed iatrogenic cancer.

Relatively speaking, it is true that 29,000 patients is a small number. And it is also true that many, if not most, of these patients were scanned for valid reasons. But population statistics are cold. They do not reflect the personal realities. They ignore the human factor. The individual who develops cancer likely does not care that they hit the cancer lottery. Why should we accept even one case of unnecessary iatrogenic cancer? Perhaps from a cost-analysis basis we should perform more scans. Yet, were it our spouse or child who developed cancer from a questionably needed CT scan, we would most certainly think differently. If neither the cold numbers nor the abstract personal rationale for re-evaluating our practice patterns sways us, then perhaps an even more personal argument will work. If we don’t think about these things and act accordingly, again, our hands will likely be forced, as the tort lawyers are already on the case.7 It is only a matter of time before an emergency physician is named in a lawsuit as an agent that caused cancer in one of these unfortunate patients.

As we move further and further into amazing technological advances, we need to continually check back with our own responsibilities to our patients and ourselves. Does this patient truly need a CT scan? Is there not, even if it requires more work, a different or better alternative? Do the risks of the CT scan truly outweigh the benefits in this particular patient? Did I explain the risks and benefits of the CT scan to the patient? Maybe as a specialty, we should take over and master the concept of the right lower quadrant ultrasound. No doubt there are questions to be asked and improvements to be made. We are extraordinarily busy on the job. We have countless things to do and only a short amount of time in which to do it. Choosing an option that might require more energy and time may not be our first choice. The CT scan is often a correct and necessary test, but it cannot be always. Sometimes not doing a test is also the right action.

References:

  1. Stoker J. et al. Imaging Patients with Acute Abdominal Pain. Radiology. 2009; 253(1):31-46.
  2. Birchard K. et al. MRI of Abdominal Pain and Pelvic Pain in Pregnant Patients. American Journal of Roentgenology. 2005; 184:452-458.
  3. Harvey R. et al. Acute Biliary Disease: Initial CT and Follow-up US versus Initial US and Follow-up CT. Radiology. 1999; 213;831-836.
  4. 72 Million were scanned total, 15 Million were at the end of life and not included.
  5. De Gonzalez A. et al. Projected Cancer Risk from Computer Tomographic Scans Performed in the United States in 2007. Archives of Internal Medicine. 2009;169(22):2071-2077.
  6. National Center for Health Statistics. Health, United States, 2008 With Chartbook Hyattsville, MD: 2009.
  7. .