Abnormal default-mode network (DMN) connectivity patterns found in patients with mild traumatic brain injury (MTBI) may provide insight into how neuronal communication and information integration are disrupted among DMN key structures after mild head injury, new research shows.
In a study comparing 23 patients with MTBI who experienced posttraumatic symptoms shortly after injury with 18 age-matched healthy control subjects, Yongxia Zhou, Ph.D., of the New York University School of Medicine, and colleagues used resting-state functional MR imaging at 3T to characterize the DMN by using independent component analysis. Results showed significantly reduced connectivity in the posterior cingulate cortex (PCC) and increased frontal connectivity around the medial prefrontal cortex (MPFC) nodes in patients with MTBI, compared with control subjects. The reduced posterior connectivity correlated clinically with neurocognitive dysfunction while the increased frontal connectivity correlated with posttraumatic symptoms.
“Our results of disrupted DMN synchrony and connectivity in MTBI suggest that resting-state functional MR imaging can be used as an additional clinical tool for detecting subtle brain injury that is not apparent with conventional MR imaging and for better understanding the underlying disease pathophysiology of postconcussion syndrome (PCS),” the authors write.
Compared with digital mammography (DM), stereoscopic DM significantly improves specificity for detection of cancer while maintaining comparable sensitivity, according to new research. The recall rate was significantly reduced with stereoscopic DM compared with DM.
In the study, Carl J. D’Orsi, M.D., of the Emory University School of Medicine and the Winship Cancer Institute at Emory University in Atlanta, and colleagues compared stereoscopic DM to 2D digital mammography in 779 patients at elevated risk of developing breast cancer due to family history. Patients received both exams in a single visit, and two experienced radiologists independently interpreted a total of 1,298 exams. Imaging findings were correlated with results of one-year follow up or biopsy.
Compared with DM, stereoscopic DM showed significantly higher specificity (91.2 percent vs. 87.8 percent) and accuracy (90.9 percent vs. 87.4 percent) for detection of cancer. Sensitivity for detection of cancer was not significantly different for stereoscopic DM (68.4 percent) compared with DM (63.2 percent), results showed.
“Use of stereoscopic DM could decrease the number of recalled findings, while preserving sensitivity for cancer detection and improving overall accuracy,” the authors write. “Further study is warranted to determine the efficacy of stereoscopic DM at a total dose equal to that of DM for breast cancer detection and in a general, non-high-risk population.”
Tomosynthesis added to digital mammography offers the dual benefit of significantly increased diagnostic accuracy and significantly reduced recall rates for noncancer cases, new research shows.
Elizabeth A. Rafferty, M.D., of Massachusetts General Hospital in Boston, and colleagues obtained mediolateral oblique and craniocaudal digital mammographic and tomosynthesis images of both breasts from 1,192 subjects recruited from five sites. Two enriched reader studies were performed to compare digital mammography with tomosynthesis against digital mammography alone. Study 1 comprised 312 cases (48 cancer cases) with images read by 12 radiologists; study 2 comprised 312 cases (51 cancer cases) read by 15 radiologists.
Diagnostic accuracy for combined tomosynthesis and digital mammography was superior to that of digital mammography alone. Two reader studies demonstrated a consistent and statistically significant gain in diagnostic accuracy (6.8 percent and 7.2 percent) when breast tomosynthesis was added to conventional digital mammography. A significant reduction in recall rates for noncancer cases was demonstrated with the addition of breast tomosynthesis for all 12 radiologists in study 1 (mean reduction, 38.6 percent) and all 15 radiologists in study 2 (mean reduction, 17.1 percent).
“Tomosynthesis imaging may improve breast cancer detection while reducing recall rates at mammographic screening, avoiding unnecessary additional testing and decreasing attendant anxiety, inconvenience and cost for women,” according to researchers.
RadiologyInfo.org, the RSNA/American College of Radiology public information website, recently launched its Patient Safety in Imaging app for tablet devices and iPhones. The app offers information related to numerous safety topics including radiation dose, radiation safety for pediatric patients and CT/MR during pregnancy. The app contains 18 videos to help illustrate content.
Download the easy-to-navigate app for iPad, iPhone and Android tablets at:
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In January, RSNA’s "60-Second Checkup" radio program focuses on increasing the understanding of radiology among the general public and informing listeners of the importance of radiology in modern medicine.
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