Coronal fat suppression fast spin echo images of the knee: Evaluation of 202 patients with arthroscopic correlation

Gli autori illustrano gli aspetti tecnici, semeiologici ed applicativi delle tecniche di soppressione del grasso, con sequenza Fast Spin Echo (FSE) T2 pesata, in Neuroradiologia. L'uso di queste tecniche risulta obbligatorio con la FSE in quanto tale sequenza è caratterizzata da un alto segnale del grasso non solo in T1p, ma anche in T2p. Ciò comporta un'alterazione dell'imaging FSE, rispetto a quello Spin Echo convenzionale, con possibilità di mascherare tutte quelle patologie anch'esse ad alto segnale in T2p. I distretti che possono risentire di tale inconveniente comprendono quelle strutture con ampia componente di grasso quali quelle della testa (orbite, clivus, osso temporale) e soprattutto del rachide, particolarmente ricco di grasso a livello del midollo vertebrale e dello spazio epidurale. Le tecniche più utilizzate sono la CHESS-FSE (Chemical Shift Selective Saturation -FSE) e la STIR-FSE (Short TI Inversion Recovery-FSE). Con entrambe la soppressione del grasso risulta soddisfacente e rapida; ne consegue un aumento della visibilità diagnostica di lesioni quali quelle flogistiche o tumorali (specie ripetitive) altrimenti mascherate dall'alto segnale del grasso.

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Comparison between Conventional and Fast Spin-Echo Stir Sequences

Acta Radiologica ◽

10.1177/02841851960373p2100 ◽

1996 ◽

Vol 37 (3P2) ◽

pp. 943-949 ◽

Cited By ~ 2

Author(s):

K. Hittmair ◽

S. Trattnig ◽

C. J. Herold ◽

M. Breitenseher ◽

J. Kramer

Keyword(s):

Spin Echo ◽

High Sensitivity ◽

Fat Suppression ◽

Inversion Recovery ◽

Fast Spin Echo ◽

T1 Relaxation ◽

Scan Time ◽

Musculoskeletal Abnormalities ◽

Pork Fat ◽

Fast Spin

Purpose: To evaluate the common characteristics and differences in contrast behavior of short-TI-inversion-recovery (STIR) and short-TI-inversion-recovery fast spin-echo (TurboSTIR) sequences. Material and Methods: Phantoms doped with increasing doses of Gd-DTPA and a pork-fat phantom were used to evaluate the dependence of the STIR and TurboSTIR signals on the T1 relaxation time. Clinical TurboSTIR images were obtained from 30 patients with musculoskeletal abnormalities and compared to conventional STIR images in 15 cases and to postcontrast TurboSTIR images in another 15 cases. Results: In the phantom measurements, a significantly shorter inversion time (TI) was needed to achieve fat suppression on TurboSTIR images, and, with an identical number of signal averages, contrast-to-noise ratios were lower on TurboSTIR images. These differences between STIR and TurboSTIR can be attributed to the contribution of stimulated echoes to overall TurboSTIR signal and can be compensated by a shorter TI and a higher number of signal averages for TurboSTIR, respectively. With these adaptations, clinical TurboSTIR and STIR images showed an identical contrast behavior with fat suppression and a high sensitivity to pathological lesions but TurboSTIR saved a significant amount of scan time and reduced some types of artifacts. Contrast uptake impaired lesion conspicuity on TurboSTIR images. Conclusion: TurboSTIR sequences should replace conventional STIR sequences and should be performed before contrast administration.

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