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  • Radiology in Public Focus

    Press releases were sent to the medical news media for the following articles appearing in recent issues of Radiology.

    July 1, 2015

    Sex Differences in Working Memory after Mild Traumatic Brain Injury: A Functional MR Imaging Study

    Female patients with mild traumatic brain injury (MTBI) had lower digit span scores than female control subjects, and functional MRI (fMRI) depicted sex differences in working memory functional activation, new research shows.

    Hui-Ling Hsu, M.D., of the University Shuang-Ho Hospital in Taiwan, and colleagues used fMRI to assess 30 patients (15 consecutive men and 15 consecutive women) with MTBI and 30 control subjects (15 consecutive men and 15 consecutive women). Two imaging studies were performed in patients: the initial study, which was performed within one month after the injury, and a follow-up study, which was performed six weeks after the first study.

    For each participant, digit span and continuous performance testing were performed before fMRI. Among female participants, the total digit span score was lower in the MTBI group than in the control group (P = .044). In initial working memory fMRI studies, hyperactivation was found in the male MTBI group and hypoactivation was found in the female MTBI group compared with control male and female groups, respectively.

    At the six-week follow-up study, the female MTBI group showed persistent hypoactivation, whereas the male MTBI group showed a regression of hyperactivation at visual comparison of activation maps. The male MTBI group also demonstrated a higher initial ß value than the male control group (P = .040), and there was no significant difference between the male MTBI group and the male control group (P = .221) at follow-up evaluation, which was comparable to findings on activation maps.

    In the female MTBI group, average ß values at both initial and follow-up studies were lower compared with those in the female control group but were not statistically significant (P = .663 and P = .191, respectively).

    “The sex differences in MTBI outcomes might lead to future development of separate management strategies for men and women with MTBI. Also, fMRI has the potential to not only provide useful objective diagnostic information associated with working memory functional sequelae, but also to provide a sensitive measurement with which to monitor disease progression and treatment,” the authors write.

    New Research Shows Gadolinium May Remain in the Brain after Contrast MRI

    New research suggests that some types of gadolinium-based contrast agents (GBCA) used in MRI exams may remain in the brain for years, but that the long-term effects are unknown.

    Three recent online Radiology studies show that the administration of some types of GBCAs results in notably varied levels of accumulation of residual gadolinium in the brain and bones of patients, even those with normal renal function.

    In their single-center study, “Intracranial Gadolinium Deposition after Contrast-enhanced MR Imaging,” Robert J. McDonald, M.D., Ph.D., of the Mayo Clinic, Rochester, Minn., and colleagues examined signal intensities from T1-weighted MR images and postmortem neuronal tissue samples from 13 patients who underwent at least four GBCA-enhanced brain MR examinations between 2000 and 2014 (contrast group) and compared them with those from 10 patients who did not receive GBCA (control group). Using inductively coupled plasma mass spectrometry, transmission electron microscopy and light microscopy, researchers confirmed the presence of gadolinium in the neuronal tissues of the global pallidus, dentate nuclei, pons and thalamus. They observed a direct relationship between the amount of gadolinium detected in their brains and the total cumulative lifetime gadodiamide doses for each of the 13 gadodiamide-exposed patients, which also correlated well with the degree of T1 shortening observed in these tissues.

    In their study, “Gadolinium-based Contrast Agent Accumulates in the Brain Even in Subjects without Severe Renal Dysfunction: Evaluation of Autopsy Brain Specimens with Inductively Coupled Plasma Mass Spectroscopy,” Tomonori Kanda, M.D., Ph.D., of Teikyo University School of Medicine in Tokyo, and colleagues concluded that GBCA administration causes gadolinium accumulation in the brain, especially in the dentate nucleus (DN) and globus pallidus (GP), even in subjects without severe renal dysfunction.

    Alexander Radbruch, M.D., J.D., of the University of Heidelberg Medical Center, Germany, and colleagues determined that a signal intensity increase in the DN and GP on T1-weighted images is caused by serial application of the linear GBCA gadopentetate dimeglumine but not by the macrocyclic GBCA gadoterate meglumine in their study, “Gadolinium Retention in the Dentate Nucleus and Globus Pallidus Is Dependent on the Class of Contrast Agent.”

    Present data now confirm that long-term multi-year residual gadolinium at these observed levels is a reality for some, but not all, of the GBCAs, according to the accompanying editorial in the June issue of Radiology, “Residual or Retained Gadolinium: Practical Implications for Radiologists and Our Patients,” by Emanuel Kanal, M.D., of the University of Pittsburgh Medical Center, and Michael F. Tweedle, Ph.D., of Ohio State University.

    “As we are now discovering new information regarding the biodistribution and pharmacokinetic behavior of at least some of these GBCAs, we suggest that the radiology community should consider these findings when using these agents,” Drs. Kanal and Tweedle write.

    Media Coverage of RSNA

    Radiology May 2015 coverIn April, 1,041 RSNA-related news stories were tracked in the media. These stories reached an estimated 624 million people.

    Coverage included U.S. News & World Report, Chicago Tribune, Today.com, Philly.com, Boston.com, KCBS-TV (Los Angeles), KCAL-TV (Los Angeles), WGN-AM (Chicago), WBBM-TV (Chicago), KING-TV (Seattle), NBCNews.com, WebMD, Medical News Today, RedOrbit and DOTmed Business News.

    Media Coverage of RSNA

    RadiologyInfo.orgNew on RadiologyInfo.org

    Do you know someone interested in becoming a radiologist? Encourage them to visit the RadiologyInfo.org Understanding Radiology page to learn more about the radiology specialty, the role a radiologist plays in a patient’s healthcare and what it takes to become a radiologist. Check out the Professions in Radiology page for more topics and information on radiology careers.

    July Public Information Outreach Activities Focus on Contrast Material and MRI

    In July, RSNA’s 60-Second Checkup radio program will focus on the use of gadolinium-based contrast material when performing brain MRI.

    Sex differences of working memory functional activation
    Sex differences of working memory functional activation in healthy control subjects in response to increased working memory load (two-back > one-back condition). A voxel-by-voxel comparison of female (left image) and male (right image) control subjects shows more activation (arrows) in female control subjects than in male control subjects (display threshold, P < .01). (Radiology 2015;35;424–437) ©RSNA 2015 All rights reserved. Printed with permission.

    Tissue localization and cellular response to gadolinium deposition
    Tissue localization and cellular response to gadolinium deposition. A, B, Transmission electron micrographs (0.2% lead citrate stain; original magnification, x10 000) of dentate nuclei tissue samples of, A, control patient 4 and, B, contrast group patient 13. X-ray spectra are also shown for selected electron-dense foci (arrow); gadolinium peaks in spectra are indicated by red overlay. C = carbon, Cs = cesium, Cu = copper, Gd = gadolinium, O = oxygen, Os = osmium, Pb = lead, Ti = titanium, V = vanadium. C, D, Photomicrographs from light microscopy (hematoxylin-eosin stain; original magnification, x100) of dentate nuclei from, C, control patient 4 and, D, contrast group patient 13. (Radiology 2015;275;3:783-791) ©RSNA 2015 All rights reserved. Printed with permission.