The response of human tumors to carbogen breathing, monitored by Gradient-Recalled Echo Magnetic Resonance Imaging.
OBJECTIVE
Gradient-Recalled Echo (GRE) Magnetic Resonance Imaging (MRI), which detects changes in blood vessel deoxyhaemoglobin content, has been investigated as a noninvasive monitor of changes in human tumor oxygenation and blood flow, in response to carbogen (95% O2, 5% CO2) breathing.


METHODS
GRE images (TE = 60 ms, TR = 200 ms, alpha = 40 degrees, 256[2] matrix) were acquired from 31 patients with primary and metastatic disease, prior to and during carbogen breathing. Three patients underwent a follow-up examination after radiotherapy.


RESULTS
Seventeen out of 34 tumors showed enhanced image intensity, consistent with an improvement in tumor oxygenation and blood flow, while 11 showed no response; 6 studies were technical failures. In one patient a metastatic node that had eluded orthodox investigation was visualized. A reduction in response was observed in the three patients studied postradiotherapy.


CONCLUSIONS
This method, which can be performed on a standard clinical MRI instrument, provides a noninvasive measurement of tumor response to oxygenation/blood flow modification. In principle, this should enable the clinician to optimize treatment protocols, such as carbogen breathing, for individual radiotherapy patients.
Griffiths
J R
JR
CRC Biomedical Magnetic Resonance Research Group, Division of Biochemistry, St. George's Hospital Medical School, London, UK.
Taylor
N J
NJ
Howe
F A
FA
Saunders
M I
MI
Robinson
S P
SP
Hoskin
P J
PJ
Powell
M E
ME
Thoumine
M
M
Caine
L A
LA
Baddeley
H
H
D000280:Administration, Inhalation; D002245:Carbon Dioxide / Q000008:administration & dosage*; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000378:metabolism; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009369:Neoplasms / Q000098:blood supply* / Q000378:metabolism*; D010100:Oxygen / Q000008:administration & dosage* / Q000378:metabolism*
D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen