In response to preapproval of sinus computed tomography for otolaryngologic evaluation of chronic rhinosinusitis does not save health care costs

We appreciate Mr. Sethi’s letter and interest in our study that showed third-party payor preapproval of sinus computed tomography (CT) scans ordered by otolaryngologists for patients with chronic rhinosinusitis (CRS) is unnecessary. We agree with Mr. Sethi that CT of the paranasal sinuses is an invaluable tool for preoperative planning in patients with CRS. Sinus CT has also been noted to be a valuable diagnostic tool in patients with CRS by the American Academy of Otolaryngology and Head and Neck Surgery (AAO-HNS), as well as by the European Position Paper on rhinosinusitis and nasal polyps consensus guidelines. In fact, the AAO-HNS further clarified the use of sinus CT with additional, specific guidelines. We agree with the use of sinus CT for diagnostic purposes in CRS patients as outlined in these consensus guidelines. To that end, we disagree with several points raised by Mr. Sethi. First, Mr. Sethi raised a concern about the radiation risk of sinus CT. We concur that the risk of malignancy from any form of radiography should be considered very seriously when weighing the risks of such imaging against the potential benefits. As Mr. Sethi has indicated, the average dose of radiation from a sinus CT scan is 0.7 mSv. The average yearly background radiation exposure from living on Earth is 3.0 mSv. Working as part of a commercial airline flight crew increases that yearly exposure to 5.0 mSv. The yearly limit of radiation exposure for “radiation workers,” such as interventional radiologists, as set by the International Commission on Radiological Protection (ICRP) and National Council on Radiation Protection and Measurements is 20.0 mSv. Thus, the radiation exposure from a sinus CT scan is approximately one-third of the excess radiation exposure above background that a commercial airline flight crew member is exposed to in just 1 year on the job. The 2007 ICRP recommendations reported a risk of 0.055 malignancies per 1.0 Sv of radiation exposure. If that risk rate were applied to a sinus CT scan causing 0.7 mSv of radiation exposure, it would translate to a roughly 1/26,000 risk of malignancy per sinus CT. However, the 2007 ICRP recommendations also state that their estimate is based on generalized epidemiologic data without specificity for the tissues irradiated and must therefore be interpreted contextually. In contrast to CT scans of other anatomic regions, when there may be direct radiation of radiosensitive tissues such as bone marrow, sinus CT scans do not directly radiate any particularly radiosensitive organs (for example, the brain is one of the least radiosensitive organs). Although radiation exposure from needless imaging should be avoided, obtaining sinus CT scans for the diagnosis of patients with CRS as described by the AAO-HNS consensus statement on the use of computed tomography for sinus disease is certainly not needless. Second, to support the notion that sinus CT scans are poor predictors of sinus disease severity, Mr. Sethi cites a study that reports sinus CT findings correlate poorly with subjectively reported sinonasal symptoms in a heterogeneous patient population, because only 50% of that study’s population had clinical symptomatology consistent with CRS (although no diagnostic criteria were described). Although we do not believe that this study cited by Mr. Sethi is applicable to a discussion of the diagnostic utility of sinus CT scan in CRS, we acknowledge that CT imaging, in isolation, is a poor predictor for clinically significant sinus disease, given that upward of 40% of asymptomatic patients may have mucosal thickening on sinus CT at any given time. However, the rationale for the inclusion of objective findings in the guideline-established diagnostic criteria for CRS, such as sinus CT, was to increase specificity of those criteria, and therefore decrease unnecessary diagnoses of CRS. False diagnosis of CRS based on clinical symptoms and anterior nasal exam findings alone are also associated with direct healthcare costs and indirect costs related to exposure of patients to unnecessary medications, such as antibiotics. Although sinus CT scans, in isolation, are poor predictors of sinus disease—which is one reason why sinus CT is not used as a screening tool for CRS— the combination of sinus CT scans with clinical criteria for CRS yields a more specific diagnostic algorithm. We agree with the use of sinus CT scans as an adjunct to the clinical exam, particularly when sinus surgery is being considered or when a patient has refractory symptoms that have not responded to medical therapy. The AAO-HNS supports the use of sinus CT in this fashion. DOI: 10.1002/lary.24725