[Morphologic MR imaging with T1-weighted sequences for radiotherapy goal volume definition of intracranial tumors. Comparison with FLASH-Turbo-FLASH and SE sequences].
BACKGROUND
The goal of this study was to compare contrast-enhanced T1-weighted Flash and Turbo-Flash sequences with conventional spin-echo sequences as a basis for planning high-precision radiotherapy.


METHODS
A total of 25 consecutive patients with different intracranial tumors and a disrupted blood-brain barrier were studied. T1-weighted Flash, Turbo-Flash and conventional spin-echo images were evaluated after controlled 30-s infusion of 0.1 mmol/kg body weight of Gd-DTPA. The evaluation of the three sequences included the measurement of the spinal- and contrast-to-noise ratios, the visual inspection of the tumors and artifacts, and the measurement of tumor size.


RESULTS
The signal- and contrast-to-noise ratios were significantly (P < 0.05-0.01) lower for Flash and Turbo-Flash than for conventional spin-echo sequences. However, visual inspection of the contrast-enhancing tumors revealed in 23 and 24 of 25 lesions on Flash and Turbo-Flash images, respectively, good or very good tumor visibility when compared with conventional spin-echo images with a reduction of imaging time by a factor of 7-8. Flash and Turbo-Flash sequences were more prone to susceptibility artifacts, conventional spin-echo sequences more to pulsation artifacts in the posterior fossa. Tumor sizes were comparable in all three techniques.


CONCLUSIONS
At present, conventional spin-echo images are superior to fast Flash and ultrafast Turbo-Flash sequences as a basis for accurate target volume definition in high-precision radiotherapy. However, fast Flash and Turbo-Flash images may be a practicable alternative to conventional spin-echo images for tumors in the posterior fossa or in patients unable to tolerate a stereotactic fixation device. Despite some limitations, Turbo-Flash sequences enable fast dynamic MR imaging combined with an acceptable morphology, which may be sufficient to target volume planning in high-precision radiotherapy.
Hawighorst
H
H
Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg.
Knopp
M V
MV
Debus
J
J
Brix
G
G
Engenhart-Cabillic
R
R
Schad
L R
LR
Grandy
M
M
Essig
M
M
van Kaick
G
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology / Q000528:radiation effects; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D003287:Contrast Media; D016371:Cranial Irradiation / Q000295:instrumentation*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation*
D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D019786:Gadolinium DTPA