title: Volumetric and two-dimensional image interpretation show different cognitive processes in learners.
abstract: OBJECTIVE
  In current practice, radiologists interpret digital images, including a substantial amount of volumetric images. We hypothesized that interpretation of a stack of a volumetric data set demands different skills than interpretation of two-dimensional (2D) cross-sectional images. This study aimed to investigate and compare knowledge and skills used for interpretation of volumetric versus 2D images.
  
  
  METHODS
  Twenty radiology clerks were asked to think out loud while reading four or five volumetric computed tomography (CT) images in stack mode and four or five 2D CT images. Cases were presented in a digital testing program allowing stack viewing of volumetric data sets and changing views and window settings. Thoughts verbalized by the participants were registered and coded by a framework of knowledge and skills concerning three components: perception, analysis, and synthesis. The components were subdivided into 16 discrete knowledge and skill elements. A within-subject analysis was performed to compare cognitive processes during volumetric image readings versus 2D cross-sectional image readings.
  
  
  RESULTS
  Most utterances contained knowledge and skills concerning perception (46%). A smaller part involved synthesis (31%) and analysis (23%). More utterances regarded perception in volumetric image interpretation than in 2D image interpretation (Median 48% vs 35%; z = -3.9; P < .001). Synthesis was less prominent in volumetric than in 2D image interpretation (Median 28% vs 42%; z = -3.9; P < .001). No differences were found in analysis utterances.
  
  
  CONCLUSIONS
  Cognitive processes in volumetric and 2D cross-sectional image interpretation differ substantially. Volumetric image interpretation draws predominantly on perceptual processes, whereas 2D image interpretation is mainly characterized by synthesis. The results encourage the use of volumetric images for teaching and testing perceptual skills.
authors.affiliation: Department of Radiology, UMC Utrecht, E01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands. Electronic address: A.vanderGijp-2@umcutrecht.nl.
authors.forename: Anouk
authors.initials: A
authors.lastname: van der Gijp
authors.affiliation: Department of Radiology, UMC Utrecht, E01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Cécile J
authors.initials: CJ
authors.lastname: Ravesloot
authors.affiliation: Department of Education, Utrecht University, Utrecht, The Netherlands.
authors.forename: Marieke F
authors.initials: MF
authors.lastname: van der Schaaf
authors.affiliation: Department of Radiology, UMC Utrecht, E01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Irene C
authors.initials: IC
authors.lastname: van der Schaaf
authors.affiliation: Department of Radiology, UMC Utrecht, E01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Josephine C B M
authors.initials: JC
authors.lastname: Huige
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Koen L
authors.initials: KL
authors.lastname: Vincken
authors.affiliation: Center for Research and Development of Education, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Olle Th J
authors.initials: OT
authors.lastname: Ten Cate
authors.affiliation: Department of Radiology, UMC Utrecht, E01.132, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
authors.forename: Jan P J
authors.initials: JP
authors.lastname: van Schaik
mesh_terms: D002983:Clinical Competence; D003071:Cognition; D054893:Cone-Beam Computed Tomography; D006801:Humans; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000592:standards*; D011871:Radiology / Q000193:education*
keywords: Radiology; cognitive processes; image interpretation; medical education; verbal protocols