[Quality control of outpatient imaging examinations in North Rhine-Westphalia, part I].

Purpose: In the state of North-Rhine Westphalia (NRW), Germany, a survey was conducted on radiologic examinations ordered by general practitioners (GPs). Part I of this study aims to collect characteristic epidemiological data and to assess structural quality.
Materials and Methods: All GPs in NRW were asked to cooperate. Participating GPs filled out a questionnaire for each patient. The patients recorded the symptoms prompting the imaging examinations. The radiologists or other physicians performing the examinations were asked to provide the images and written reports and to complete a questionnaire. Two university radiologists documented the pertinent test data from the submitted images and written records. Independently of each other, five university radiologists anonymously reviewed the image quality of each examination using structured questionnaires.
Results: A total of 920 patients gave their informed consent and participated. Questionnaires from 787 patients, 852 GPs and 611 radiologists or other interpreting physicians as well as the complete survey data from 530 examinations were available. Of 1503 examinations, conventional radiography made up 52 %, sonography 17 %, computed tomography (CT) 13 % and magnetic resonance imaging (MRI) 5 %. Most indications involved the musculoskeletal (37 %) and respiratory systems (24 %). Physicians without board certification in radiology interpreted 1 % of the CT examinations, 26 % of the radiographic examinations and 71 % of the sonographic examinations. Of the 174 self-referrals, 1 % involved CT, 33 % conventional radiography and 66 % sonography. Written reports were available for 95 % of all 469 examinations performed by radiologists and 74 % of all 127 examinations conducted by non-radiologists. Only 44 % of the 23 sonographic studies were self-referrals by the patient's GP. On average, the radiographic techniques were acceptable in terms of diagnostic information and radiation hygiene. Conventional radiographs were better exposed when obtained by radiologists than by non-radiologists (p = 0.038). The delineation of anatomical structures was rated as good to acceptable for MRI, CT and conventional radiography, while the image quality was rated as diagnostically insufficient for sonography (p < 0.0001). The image quality of radiographic and sonographic examinations performed by radiologists was superior in comparison to examinations performed by physicians without board certification in radiology (p < 0.0001).
Conclusion: Examination technique and imaging quality of MRI, CT and conventional radiography performed on outpatients were in an acceptable diagnostic range, whereas the quality of sonography was inadequate.