title: A smartphone client-server teleradiology system for primary diagnosis of acute stroke.
abstract: BACKGROUND
  Recent advances in the treatment of acute ischemic stroke have made rapid acquisition, visualization, and interpretation of images a key factor for positive patient outcomes. We have developed a new teleradiology system based on a client-server architecture that enables rapid access to interactive advanced 2-D and 3-D visualization on a current generation smartphone device (Apple iPhone or iPod Touch, or an Android phone) without requiring patient image data to be stored on the device. Instead, a server loads and renders the patient images, then transmits a rendered frame to the remote device.
  
  
  OBJECTIVE
  Our objective was to determine if a new smartphone client-server teleradiology system is capable of providing accuracies and interpretation times sufficient for diagnosis of acute stroke.
  
  
  METHODS
  This was a retrospective study. We obtained 120 recent consecutive noncontrast computed tomography (NCCT) brain scans and 70 computed tomography angiogram (CTA) head scans from the Calgary Stroke Program database. Scans were read by two neuroradiologists, one on a medical diagnostic workstation and an iPod or iPhone (hereafter referred to as an iOS device) and the other only on an iOS device. NCCT brain scans were evaluated for early signs of infarction, which includes early parenchymal ischemic changes and dense vessel sign, and to exclude acute intraparenchymal hemorrhage and stroke mimics. CTA brain scans were evaluated for any intracranial vessel occlusion. The interpretations made on an iOS device were compared with those made at a workstation. The total interpretation times were recorded for both platforms. Interrater agreement was assessed. True positives, true negatives, false positives, and false negatives were obtained, and sensitivity, specificity, and accuracy of detecting the abnormalities on the iOS device were computed.
  
  
  RESULTS
  The sensitivity, specificity, and accuracy of detecting intraparenchymal hemorrhage were 100% using the iOS device with a perfect interrater agreement (kappa=1). The sensitivity, specificity, and accuracy of detecting acute parenchymal ischemic change were 94.1%, 100%, and 98.09% respectively for reader 1 and 97.05%, 100%, and 99.04% for reader 2 with nearly perfect interrater agreement (kappa=.8). The sensitivity, specificity, and accuracy of detecting dense vessel sign were 100%, 95.4%, and 96.19% respectively for reader 1 and 72.2%, 100%, and 95.23% for reader 2 using the iOS device with a good interrater agreement (kappa=.69). The sensitivity, specificity, and accuracy of detecting vessel occlusion on CT angiography scans were 94.4%, 100%, and 98.46% respectively for both readers using the iOS device, with perfect interrater agreement (kappa=1). No significant difference (P<.05) was noted in the interpretation time between the workstation and iOS device.
  
  
  CONCLUSIONS
  The smartphone client-server teleradiology system appears promising and may have the potential to allow urgent management decisions in acute stroke. However, this study was retrospective, involved relatively few patient studies, and only two readers. Generalizing conclusions about its clinical utility, especially in other diagnostic use cases, should not be made until additional studies are performed.
authors.affiliation: Imaging Informatics Lab, Department of Radiology, University of Calgary, Calgary, AB, Canada. rmitch@ucalgary.ca
authors.forename: J Ross
authors.initials: JR
authors.lastname: Mitchell
authors.forename: Pranshu
authors.initials: P
authors.lastname: Sharma
authors.forename: Jayesh
authors.initials: J
authors.lastname: Modi
authors.forename: Mark
authors.initials: M
authors.lastname: Simpson
authors.forename: Monroe
authors.initials: M
authors.lastname: Thomas
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
authors.forename: Mayank
authors.initials: M
authors.lastname: Goyal
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging; D040421:Cell Phone; D002533:Cerebral Angiography; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging; D034201:Computers, Handheld; D006801:Humans; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D020521:Stroke / Q000000981:diagnostic imaging*; D019112:Teleradiology / Q000295:instrumentation* / Q000592:standards*; D014057:Tomography, X-Ray Computed