Contrast optimization for the detection of focal hepatic lesions by MR imaging at 1.5 T
| Autor: | Thomas L. Lawson, JD Cates, GM Kellman, William D. Middleton, RE Hendrick, J B Kneeland, W D Foley |
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| Rok vydání: | 1987 |
| Předmět: |
Lesion detection
Cysts business.industry Pulse (signal processing) Liver Diseases media_common.quotation_subject Echo time Liver Neoplasms General Medicine Image Enhancement Respiratory compensation Magnetic Resonance Imaging Mr imaging Nuclear magnetic resonance Repetition Time Artifact suppression Humans Medicine Contrast (vision) Radiology Nuclear Medicine and imaging Hemangioma business media_common |
| Zdroj: | American Journal of Roentgenology. 149:1155-1160 |
| ISSN: | 1546-3141 0361-803X |
| DOI: | 10.2214/ajr.149.6.1155 |
| Popis: | The relative efficacies of different spin-echo pulse sequences at 1.5 T were evaluated in the detection of focal hepatic disease. Pulse sequences compared were spin-echo with a repetition time (TR) of 200 msec and echo time (TE) of 20 msec, with six excitations; TR = 300 msec, TE = 20 msec, with 16 excitations (T1-weighted sequences); and a double spin-echo with TR = 2500 and TE = 25 and 70, with two excitations (proton-density-weighted and T2-weighted pulse sequences, respectively). Respiratory-motion compensation, which involved a recording of the phase-encoding gradients (Exorcist), was used for the last two sequences. Spin-echo with TR = 2500 msec and TE = 70 msec was superior in lesion detection and contrast-to-noise ratio. The proton-density-weighted and T2-weighted sequences with respiratory compensation produced better artifact suppression than did the short TR, short TE T1-weighted sequence with temporal averaging. In contradistinction to prior results at 0.6 T, T2-weighted pulse sequences appear superior to T1-weighted pulse sequences with multiple excitations for both lesion detection and artifact suppression at 1.5 T. |
| Databáze: | OpenAIRE |
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