CHICAGO - Although they yield image quality noticeably inferior to standard CT exams, portable abdominal CT studies can provide a valuable diagnostic alternative for patients too sick to travel to the radiology department, according to research presented Tuesday at the RSNA meeting.
To determine the clinical impact of portable abdominal CT on management of critically ill patients, researchers from the Massachusetts General Hospital in Boston reviewed exams conducted between 1998 and 2000 on a Tomoscan M/EG portable CT scanner (Philips Medical Systems). Using the hospital’s radiology information system, the researchers identified 209 consecutive portable CT studies from 180 patients, said MGH’s Dr. Peter Hahn.
The study team assessed image quality using a 10-point scoring system based on the sum of 9 anatomic features and 1 point for absence of gross problems. Qualitative assessment was made using a 5-point scale (5=best, 1=uninterpretable). These measures were applied to the portable CT studies and 67 standard CT exams taken recently on the same patients.
For feature visualization, portable CT exams received an average score of 5.95, while standard CT received a 7.18 score. In qualitative rankings, portable CT received an average 2.49 score, while standard CT posted a mean of 2.97.
The study team also reviewed the effect of the portable CT on patient management. In 54 of the 209 studies, the portable CT exam supported the clinical diagnosis for which the study was performed. The portable CT study confirmed the clinical diagnosis of infection in 30 of the 128 cases.
Eighteen surgical or percutaneous interventions were indicated by portable CT findings. In 48 of the 209 studies, portable CT changed patient management.
"Patients who can be transported to the (radiology) department for a standard CT should be transported because the image quality is better," Hahn said. "However, portable CT does provide a unique imaging modality for diagnosis of major pathology in desperately ill patients."
In a response to an audience question on the role of ultrasound, Hahn said that ultrasound should remain the first portable imaging option in most of these patients.
"But if ultrasound is unrevealing, then portable CT is another option," he said.
Radiologists should also be sure to educate referring physicians on the limitations of portable CT, Hahn said.
"The most important thing we can do when we interpret (portable CT studies) is not to give a false sense of security to the referring physician who orders the scan as to how much diagnostic information can be inferred from the portable CT study," Hahn said.
By Erik L. Ridley
AuntMinnie.com staff writer
November 27, 2001
For the rest of our coverage of the 2001 RSNA meeting, go to our RADCast@RSNA 2001.
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