• Researchers at the Medical University of South Carolina (Charleston, SC) have used contrast-enhanced multidetector (MD) CT to diagnose aortic injury in trauma patients. MDCT-based diagnosis can eliminate the need for catheter angiography - an invasive technique that involves passing a catheter through a large artery or vein - and enable patients to be taken directly to surgery.
"Coming up with a definitive diagnosis of aortic injury takes only minutes with 64-[slice] MDCT without the need for mobilizing an angiography team," said Scott Steenburg, lead author of the study. "For the patient, this means saving precious time, as morbidity and mortality increase dramatically for untreated aortic injuries, even with only a few hours of delay."
For the clinical study, Steenburg and his team reviewed 581 patients who had undergone imaging for suspected aortic injury. MDCT accurately diagnosed injury in 16 patients. In the 10 cases where catheter angiograms were also performed (following positive, negative or equivocal MDCT diagnoses), the findings between the two methods correlated in all cases.
"Since March 2005, practically every trauma patient seen in our trauma centre gets some imaging with our 64-MDCT scanner. However, we knew of no study showing the effectiveness of 64-MDCT for aortic injuries," said Steenburg. "Recently, our surgeons have been taking patients with evidence of aortic injuries directly to surgery and we wanted to look back at the data to see how well we were doing with 64-MDCT."
Steenburg noted that MDCT is now becoming a standard technique for rapid evaluation of trauma patients and that direct catheter angiograms for aortic injuries are rarely performed anymore. "The surgical staff is confident in our diagnoses because of the excellent images we are able to generate," he said.
• According to a recent study at the Health Sciences Center in Winnipeg, Canada, CT angiography (CTA) offers a detection rate of nearly 100% for acute ruptured cerebral aneurysms. CTA - a less invasive alternative to catheter angiography - involves injecting contrast material into a small peripheral vein in order to visualize blood flow throughout the body.
The Winnipeg researchers examined 171 patients with acute subarachnoid haemorrhage (bleeding into the space surrounding the brain) who underwent preoperative 3D CTA. The technique correctly detected the ruptured aneurysm in 170 cases when compared to intraoperative findings. In the 22 cases in which there was more than one aneurysm, CTA correctly identified the ruptured ones every time.
The sensitivity of CTA for detecting ruptured aneurysm in the setting of acute subarachnoid haemorrhage was calculated as 99.4%. "In the one case where CTA initially did not demonstrate the ruptured aneurysm, the study was severely degraded with motion artefact," explained lead author Bijal Patel.
Patel continued: "While CTA provides detailed information on the features of the aneurysm, its true accuracy in the clinical setting could only be determined when compared to surgical findings. In our institution it is standard practice to follow a confirmed subarachnoid haemorrhage with a CTA. We felt it was important to evaluate the utility of CTA as the primary diagnostic investigation in detecting acute ruptured cerebral aneurysms."
The authors concluded that CTA can provide fast and accurate diagnostic and anatomical information. "Furthermore, a positive CTA in the setting of acute spontaneous subarachnoid haemorrhage is sufficient for intraoperative treatment planning," noted Patel.
• At the Charite Campus Benjamin Franklin in Berlin, Germany, researchers have demonstrated that CTA alone provides an effective, noninvasive means by which to detect peripheral vascular disease.
The study analysed 50 patients who underwent CTA, as well as digital subtraction angiography (DSA), of the peripheral arteries. The resulting images were evaluated by two radiologists, who observed no significant differences in diagnostic quality between CTA and DSA. In addition, for 49 out of the 50 cases, patient-management decisions based on CTA alone were equivalent to those based on both CTA and DSA.
"CTA is an examination that is easily performed on almost every recent CT scanner," said Bernhard Meyer, lead author of the study. "In comparison to DSA, the physician needs no special knowledge (for example, puncture technique or catheter handling), and they need no further assistance by a nurse to perform an angiography. The results show that there is a high agreement concerning the therapeutic decision based on either CTA or DSA. Therefore, in my eyes, DSA can be replaced by CTA alone."
• A study undertaken by researchers at the Emory University School of Medicine (Atlanta, GA) and Massachusetts General Hospital (Boston, MA) has demonstrated that ultralow-dose MDCT of the abdomen and pelvis can provide useful diagnostic information and reduce the hospital stay of patients with acute nonspecific abdominal pain.
"Patients with unspecified abdominal pain usually have to get abdominal X-rays, which lack accuracy in patients with acute abdominal pain," explained Emory's Unni Udayasankar. "Our study focused on the feasibility of substituting three-view abdominal X-rays with ultralow-dose MDCT and assessing its impact on patient care and management."
The team analysed results from 163 patients with nonspecific abdominal pain who underwent MDCT of the abdomen and pelvis. The radiation dose received was comparable to that of the three-view X-rays. Based on negative MDCT findings, 61 patients (37%) were discharged the same day from the emergency department. The mean duration of the hospital stay for the study population was 2.4 days.
"With developments in CT technology it is now feasible to acquire good-quality images at extremely low radiation doses," said Udayasankar. "CT studies improved reader confidence and resulted in early diagnosis and patient management."