Brain temperature measured by using proton MR spectroscopy predicts cerebral hyperperfusion after carotid endarterectomy

Radiology. 2010 Sep;256(3):924-31. doi: 10.1148/radiol.10090930.


Purpose: To determine whether brain temperature measured by using preoperative proton magnetic resonance (MR) spectroscopy could help identify patients at risk for cerebral hyperperfusion after carotid endarterectomy (CEA).

Materials and methods: Institutional review board approval and informed consent were obtained. Acquisition of proton MR spectroscopic data by using point-resolved spectroscopy without water suppression was performed before CEA in the bilateral cerebral hemispheres of 84 patients with unilateral internal carotid artery stenosis (> or =70%) and without contralateral internal carotid artery steno-occlusive disease. Brain temperature was calculated from the chemical shift difference between water and N-acetylaspartate signals at proton MR spectroscopy. Cerebral blood flow (CBF) was also measured by using single photon emission computed tomography and N-isopropyl-p-[(123)I]-iodoamphetamine before and immediately after CEA and on the 3rd postoperative day. The relationship between each variable and the development of post-CEA hyperperfusion (CBF increase > or = 100% compared with preoperative values) was evaluated with univariate statistical analysis followed by multivariate analysis.

Results: A linear correlation was observed between preoperative brain temperature difference (the value in the affected hemisphere minus the value in the contralateral hemisphere) and increases in CBF immediately after CEA (r = 0.763 and P < .001) when the preoperative brain temperature difference was greater than 0. Cerebral hyperperfusion immediately after CEA was observed in nine patients (11%). Elevated preoperative brain temperature difference was the only significant independent predictor of post-CEA hyperperfusion. When elevated brain temperature difference was defined as a marker of hemodynamic impairment in the affected cerebral hemisphere, use of preoperative brain temperature difference resulted in 100% sensitivity and 87% specificity, with a 47% positive predictive value and a 100% negative predictive value for the prediction of post-CEA hyperperfusion. Hyperperfusion syndrome developed on the 3rd and 4th postoperative days in two of the nine patients who exhibited hyperperfusion immediately after CEA.

Conclusion: Brain temperature measured by using preoperative proton MR spectroscopy may help identify patients at risk for post-CEA cerebral hyperperfusion.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Blood Volume
  • Body Temperature*
  • Carotid Stenosis / surgery*
  • Cerebrovascular Circulation / physiology*
  • Chi-Square Distribution
  • Endarterectomy, Carotid / adverse effects*
  • Female
  • Humans
  • Magnetic Resonance Spectroscopy / methods*
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Protons
  • ROC Curve
  • Risk Factors
  • Sensitivity and Specificity
  • Statistics, Nonparametric
  • Tomography, Emission-Computed, Single-Photon


  • Protons