Ultra-low dose CT detects extremity fractures better than radiography
Ultra-low dose computed tomography (ULD-CT) detects significantly more fractures than digital radiography, Swedish radiologists report in the Sept. 9, 2019, online edition of Skeletal Radiology. Additionally, ULD-CT can provide additional clinically important information at a comparable radiation dose.
Radiologists from Karolinska University Hospital in Stockholm investigated the performance of an ULD-CT protocol compared to radiographs for extremities in an acute clinical scenario with respect to diagnostic accuracy, radiation dose, and workflow parameters in the radiology department. The study cohort consisted of 203 consecutive patients over age 16 years admitted to the hospital’s emergency department for 207 extremity injuries between December 2017 and October 2018.
The patients underwent digital radiography and CT exams, which were initially interpreted by on-call radiologists and radiology residents, followed by a review by both a consultant radiologist and an experienced musculoskeletal and trauma radiologist.
An orthopedic surgeon reviewed case reports in instances when ULD-CT provided additional diagnostic information to determine if there would be an impact on recommended treatment choices, which included surgery, casting, or functional treatment with a compression bandage.
Lead author Zlatan Alagic, MD, and colleagues reported that ULD-CT diagnosed one or more acute fractures in 109 extremities compared to 73 with digital radiography. Additional fractures and fracture-related findings of malalignment and articular involvement were visualized in 33 extremities only on ULD-CT.
ULD-CT also confirmed or ruled out suspected fractures in 19 cases. In nine cases, ULD-CT provided important additional information about non-acute-fracture-related findings.
Based on ULD-CT findings, the orthopedic surgeon recommended 34 treatment changes that he would not have recommended by relying only on digital radiography. He recommended upgraded treatment for 27 extremities and downgraded treatment for seven. The authors wrote that two extremities were upgraded to surgery from a functional treatment recommendation and one from casting to surgery. Treatment for 24 extremities was changed from compression bandaging to casting. The seven cases of downgraded treatment represented replacing a cast with a compression bandage.
While they found that the mean effective dose of ULD-CT and digital radiography for each type of extremity exam was comparable, the researchers found that the mean combined exam time to preliminary report was approximately 2 minutes shorter for ULD-CT. “This implies that the extra amount of electronic information that ULD-CT provided does not lead to a reduction in workflow for acute emergency situations,” they wrote.
Radiologic technologists also reported that ULD-CT was less painful and less stressful for patients because there was no need to manipulate the injured body part. They also said the exam was faster with the single-shot approach and easier for them to perform than digital radiography because specific projections were not necessary.
The authors acknowledged that ULD-CT was significantly more expensive than digital radiography. They recommend a detailed cost analysis study to determine if clinical benefits and related costs can justify the use of diagnostically superior ULD-CT.
REFERENCE
- Alagic Z, Bujila R, Enocson A, et al. Ultra-low-dose CT for extremities in an acute setting: initial experience with 203 subjects. Skeletal Radiol. Published online September 9, 2019. doi: 10.1007/s00256-019-03309-7.