Jessica Lee Wisnowski PhD, Presenter: Nothing to Disclose

Stefan Bluml PhD, Abstract Co-Author: Nothing to Disclose

Tai-Wei Wu, Abstract Co-Author: Nothing to Disclose

Ida Ashoori, Abstract Co-Author: Nothing to Disclose

Ashok Panigrahy MD, Abstract Co-Author: Nothing to Disclose

Claire McLean, Abstract Co-Author: Nothing to Disclose

Istvan Seri MD, PhD, Abstract Co-Author: Grant, Covidien AG

Marvin Dale Nelson MD, Abstract Co-Author: Nothing to Disclose

To measure absolute temperatures in different brain regions in newborns with suspected hypoxic-ischemic injury (HII) undergoing hypothermia therapy (HT) and to determine to what extent the targeted cooling has been achieved.

11 patients had MR examination during and after HT treatment, including MR spectroscopy (PRESS, echo time 35 msec) of three brain regions: basal ganglia (BG), thalamus (Thal), parietal grey matter (GM). Spectra were processed offline using iNMR (Mestrelab Research, Molfetta, Italy) and the tissue temperature was determined from the chemical shift difference of the N-acetyl-aspartate peak and the water resonance (figure). All studies were performed on a 3T clinical system (Philips, Achieva). Rectal temperatures during MR scans were recorded. The study was approved by the local IRB.

Mean brain temperature (average BG, Thal, GM) during HT was 1.1 degrees above the rectal temperature 34.1+/-0.9 vs. 33.0+/-0.3, p<0.01), whereas post HT it was 0.8 degrees above rectal temperature (36.8 +/- 1.2 vs. 36.0 +/- 0.5, p=0.05). Temperature in BG during HT was reduced by 3.1+/- 1.4 degrees, whereas in Thal a 2.5 +/- 1.3 and GM a 2.6+/-1.8 decline was observed. During HT, BG was significantly colder than the Thal (p<0.05). Post HT, temperatures in the three brain region were not significantly different.

HT is standard care for infants with suspected HII. While HT reduces incidences of death, it is unclear whether survivors benefit from HT by reduced long-term neurological problems. This study confirms the need to measure the actual brain temperatures instead of proxy rectal temperatures to better understand the impact of HT in different patients and in different brain regions. Long-term follow-up is needed to determine whether temperature itself measured in different brain regions is an indicator for outcome.

HT fails to reduce brain temperatures by the targeted difference and furthermore does not reduce temperatures equally across patients and brain regions.

Wisnowski, J, Bluml, S, Wu, T, Ashoori, I, Panigrahy, A, McLean, C, Seri, I, Nelson, M, Brain Temperature Determination in Newborns with Suspected Hypoxic-ischemic Injury Undergoing Hypothermia Therapy.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044401.html