Last year, we reported how the University of Calgary’s Faculty of Medicine were doing a stroke trial comparing the performance of diagnostic radiology on a mobile device using the ResolutionMD app verse a standard clinical reading work station.
Our article last year focused on how Health Canada, analogous to our FDA, had approved the device for medical diagnostic use.
At that time, faculty were reporting the performance on both types of devices (mobile versus desktop) was the same. The Calgary researchers have since published the details of the study. Although we’ve known the results for over a year, their study produced interesting data from a mobile bandwidth perspective that could shed light on key limiting factors for mobile diagnostic radiology.
This isn’t the first time a study has been done to assess the performance of mobile diagnostic imaging. In 2009 we reported how researchers at Johns Hopkins showed how OsiriX, another mobile radiology viewing tool for the iPhone, had been shown to accurately diagnose acute appendicitis.
Partial Excerpt of Methods section from Calgary 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 results showed no statistical difference between mobile radiology diagnosing and a traditional radiology workstation — although we’ve put caveats of the study at the end of this article.
The study raised some great questions regarding the capability of traditional mobile bandwidth speeds and the ability to view radiology images properly:
In our experience, a single visualization server can accommodate 10 or more simultaneous iOS device users and is capable of delivering and displaying up to 14 frames per second on an iOS device connected over a 802.11g Wi-Fi network. The frame rate was enough to provide sufficient interactivity for comfortable use.
However, the frame rate on a 3G cellular network was 1 to 4 frames per second, which was insufficient for practical use. We know that fourth generation (4G) cellular networks are now installed in many metropolitan centers. We estimate that the higher bandwidth of these new cellular networks should allow 10 to 15 frames per second to be delivered to smartphones. However, currently only the iPhone 4 and a few Android-based smartphones are capable of utilizing greater network bandwidth.
It would have been great if the authors had included the exact bandwidth they had available, but they clearly had difficulties using the traditional 3G network available in their area. The iPhone 4 “4G network” they are referring to above is AT&T’s controversial branding of HSPA-plus as “4G”.
The reason why bandwidth speeds are important is because rendering and manipulation of the radiology images is done on a separate server. This is crucial because it prevents the images from being stored locally on the phone, where security can often be variable. Obviously, if you are at a remote clinic, with no Wi-Fi, and only an EDGE data connection, secure mobile radiology viewing is rendered moot.
The results of this study clearly showed that although diagnostic radiology is possible in a mobile setting, for a physician to be truly “un-tethered” — bandwidth speeds are crucial.
This was a retrospective study (not ideal) ; Involved relatively few patient studies and only two readers — the Power of the study could be questioned; Some of the study participants directly involved also produced the ResolutionMD app (disclosed by authors).
A Smartphone Client-Server Teleradiology System for Primary Diagnosis of Acute Stroke. Journal of Medical Internet Reserach. Vol 13, No 2 (2011)
Authors: J Ross Mitchell PhD, Pranshu Sharma MD, Jayesh Modi MD, Mark Simpson, Monroe Thomas, Michael D Hill MD, Mayank Goyal MD.
iTunes link to Resolution MD Mobile Lite