ABSTRACT
The artificial nature of studies performed in referral centers is problematic in other respects. Series are usually constructed by selecting key disorders from a hospital diagnostic codex, with appropriate care taken to ensure that a final diagnosis is secure. However, disorders that are seldom encountered in routine practice tend to be referred to specialist centers. Thus, in HRCT diagnostic series of diffuse lung disease, rare entities such as lymphangioleiomyomatosis and Langerhans’ cell histiocytosis tend to be over-represented and evaluation is confined to the diffuse lung diseases without consideration of more frequently encountered disorders that may simulate diffuse lung disease. Diagnostic HRCT series in diffuse lung disease do not include patients with heart failure, metastatic malignancy (other than lymphangitis carcinomatosis), chronic infection, and bronchiectasis. However, as many clinicians have found to their cost, all these disorders may be overlooked once a diagnostic assumption of diffuse lung disease has been made. Radiologists who seek to apply HRCT series to routine diagnosis receive little or no guidance on the manifestations of these disorders and will often be biased towards a diagnosis of diffuse lung disease by the wording of a request form. The misdiagnosis of cancer as a benign disorder is a major source of stress for patients and clinicians, and this, almost certainly, occurs more often than is generally appreciated.
