RSNA: iPhone provides accurate appendicitis diagnosis only the beginning?
CHICAGO—Radiologists can accurately diagnose acute appendicitis from a remote location with the use of a handheld device or mobile phone equipped with OsiriX mobile software, based on study results presented Monday at the 2009 annual meeting of the Radiological Society of North America (RSNA). The researchers are seeking to study this technology for other conditions that require an expedited diagnoses.

Advances in handheld computing, such as OsiriX, have created the possibility of viewing full DICOM data sets from a remote location. While this would not be advisable for “formal interpretations,” according to principal investigator Asim F. Choudhri, MD, it may serve a role for emergent consultations.

As the diagnostic ability of this tool is unproven, Choudhri said that he and his colleagues at Johns Hopkins University in Baltimore sought to evaluate the ability to identify signs of acute appendicitis on abdominal CT studies using an iPhone-based DICOM viewer.

“The goal is to improve the speed and accuracy of medical diagnosis, as well as improve communications among different consulting physicians," said Choudhri, who is a fellow in the division of neuroradiology, and did not report any financial disclosures connected to the study.

Ten years ago, before the use of CT scans, up to 20 percent of appendectomies removed a normal appendix because “no one wanted to miss a case of acute appendicitis,” Choudhri explained. “With the use of CT scans, that 20 percent has dropped to less than 5 percent. CT also shows evidence of whether the appendix is perforated or abscessed—all the factors that the surgeon needs to know prior to the removal of the appendix.”

In many academic centers, residents or fellows provide preliminary interpretations of abdominal CT scans overnight and on weekends, according to Choudhri, but in many cases, immediate consultation is required or, at the very least, is beneficial. “This is where we thought a handheld device would be helpful,” he said.

Five senior radiology residents who were blinded to the diagnosis retrospectively reviewed on the iPhone 25 abdomen and pelvis CT studies performed on patients with right lower quadrant pain. All patients had either surgical confirmation of the diagnosis of acute appendicitis or follow-up clinical evaluation confirming no acute appendicitis.

The residents correctly identified 15 cases of acute appendicitis on 74 of 75 interpretations (99 percent), with one false negative. No false positive readings were seen in this study. They correctly identified appendicoliths on 35 of 40 interpretations (88 percent). Also, all five readers correctly identified the abscesses.

The researchers also found there was greater than 90 percent agreement on the presence of peri-appendiceal stranding and free fluid. The iPhone measurement of appendiceal diameter averaged 0.9 mm larger than the value obtained on a PACS workstation

In this preliminary investigation, Choudhri said that the evaluation for acute appendicitis on abdominal CT studies using a portable device DICOM viewer can be performed with good concordance to reads performed on PACS workstations.

He pointed out that patient privacy concerns would have to be addressed and the FDA would have to approve the technology before any handheld mobile device could be considered applicable for clinical use, adding that this technique has great potential for improving emergency room care.

“We recommend that any diagnosis that is made over the iPhone is confirmed as soon as possible through conventional methods,” Choudhri said. “Currently, it is not used for final diagnosis, but our goal is to expedite the process and assist the surgeon.”

With a look to the future, Choudhri said that there are five or six other conditions that may be considered for investigation after this proof-of-concept study, one being bleeding in the brain.