INTRODUCTION: 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. CONCLUSION: 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.
INTRODUCTION: 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. CONCLUSION: 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.