Experience counts for imaging orders
CHICAGO—The longer a radiologist is in practice, the lower their rate of requests for additional diagnostic imaging procedures, according to research conducted at Massachusetts General Hospital (MGH) in Boston and presented this week at the 2008 scientific assembly and annual meeting of the Radiological Society of North America (RSNA).

“Knowledge of recommendation rates in radiology reports can be important predictors of radiology practice,” said Pragya Dang, MBBS. “We hypothesized that radiologists’ number of years in practice and number of exams interpreted by them affect the recommendation rates in their reports.”

A recommendation was defined as a request or suggestion in an imaging report for further diagnostic imaging studies, she said.

“There are variations observed in the recommendation practice amongst radiologists and it is important to identify these variations to homogenize the practice regardless of years in practice,” Dang noted.

A Natural Language Processing program developed at the facility, Leximer, was used classify unstructured radiology reports into those with and without recommendations.

The results of the Leximer classification and additional information from radiology reports in the institution’s RIS--including the radiologist names, imaging modality, subspecialty, and date of exam--were combined to create a comprehensive database. Her group analyzed MGH’s 105,237 CT exams performed in 2007 for recommendation rates of different radiologists from different subspecialties.

The radiologists were stratified into four categories based on years in practice: fellow; junior radiologist (less than four years experience); intermediate radiologist (four to 15 years experience); and senior radiologist (more than 15 years experience).

The recommendation rates for different radiologist experience categories were assessed by the researchers; as well as correlation between the number of exams interpreted and the recommendation rates for each radiologist.

A decrease in recommendation rates was observed with an increase in years of experience of radiologists in abdominal imaging, neuroradiology, thoracic and musculoskeletal radiology.

“Fellows had higher recommendation rates than junior radiologists; junior radiologists had higher recommendation rates than intermediate radiologists; and intermediate radiologists had pretty much the same recommendation rates as senior radiologists,” Dang said.

She noted that a negative correlation was observed between number of exams interpreted to the recommendation rates in radiology reports for all specialties (-0.17 to -0.54), with abdominal and neuroradiology having the highest negative correlation.

“Recommendation rates in CT reports decrease with an increase in years of practice in abdominal, musculoskeletal, and neuroradiology,” Dang reported. “A moderate negative correlation is observed between number of exams interpreted and recommendation rates for abdominal imaging and neuroradiology.”