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Modification of Tumour Perfusion and Oxygenation Monitored by Gradient Recalled Echo MRI and 31 P MRS
Author(s) -
Howe Franklyn A.,
Robinson Simon P.,
Griffiths John R.
Publication year - 1996
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199608)9:5<208::aid-nbm418>3.0.co;2-h
Subject(s) - carbogen , perfusion , oxygenation , blood flow , calcitonin gene related peptide , nuclear medicine , chemistry , calcitonin , intensity (physics) , magnetic resonance imaging , medicine , nuclear magnetic resonance , radiology , neuropeptide , physics , receptor , quantum mechanics
Gradient recalled echo (GRE) 1 H images can be used to monitor changes in blood oxygenation via the dephasing effects of paramagnetic deoxyhaemoglobin (Hb). We have modulated the blood flow/oxygenation of GH3 rat tumours by i.v. calcitonin gene‐related peptide (CGRP) or carbogen (95% O 2 , 5% CO 2 ) inhalation, and obtained GRE 1 H images interleaved with 31 P spectra before, during and after the insult. With CGRP the GRE image intensity decreased (6/10) by >10% with a concomitant 40% decrease (4/4) in βNTP/P i and a small decrease in pH. Both the image intensity and 31 P spectra returned to near their pre‐CGRP levels after 50 min, consistent with a transient episode of hypoxia. Carbogen breathing (5/5) caused >40% increases in average GRE image intensity, with no significant changes in the 31 P spectra (4/4). Three‐dimensional GRE images were obtained to confirm that a T 2 * increase, rather than just an "in‐flow' effect due to increased blood flow, was responsible for the GRE enhancement. Increases in average image intensity >40% were observed for the three‐dimensional GRE images (2/2), indicating a T 2 * increase. Using Hb as an endogenous contrast agent, the high sensitivity of the GRE technique may provide a method of monitoring heterogeneous tumour perfusion and oxygenation, both in the laboratory and the clinic.