Fast flair imaging of the brain using the fast spin-echo and gradient spin-echo technique

Small hepatic lesions found on single-phase helical CT in patients with malignancy: Diagnostic capability of breath-hold, multisection fluid-attenuated inversion-recovery (FLAIR) MR imaging using a half-fourier acquisition single-shot turbo spin-echo (HASTE) sequence

PURPOSE

To evaluate the diagnostic capability of breath-hold, multisection fluid-attenuated inversion-recovery (FLAIR) imaging using a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence in combination with T2-weighted fast spin-echo (FSE) magnetic resonance (MR) sequences for small hepatic lesions found on CT in patients with malignancy.

MATERIALS AND METHODS

This study included 48 patients with extrahepatic malignancy who underwent both CT and MR examinations. There were a total of 112 small hepatic lesions (73 cysts and 39 liver metastases, <2 cm in diameter) that showed low attenuation on enhanced CT. Three radiologists independently reviewed the CT and MR (FLAIR-HASTE and T2-weighted FSE) images and assigned a confidence level to their evaluation (cyst or metastasis) on a five-point scale.

RESULTS

All three reviewers were significantly better able (P < 0.05) to differentiate small hepatic cyst from liver metastasis with combined FLAIR-HASTE and T2-weighted FSE images (Az values = 0.997-0.999) than with CT (0.917-0.932). The mean values of sensitivity, specificity, and accuracy were significantly higher (P < 0.001) for T2-weighted FSE with FLAIR-HASTE (96.6%, 96.8%, and 96.7%, respectively) than for CT (76.9%, 61.6%, and 67.3%, respectively). A confident diagnosis was rendered in 12 of 112 lesions (10.7%) on the basis of CT, and this rate increased to 83 of 112 (74.1%) on the basis of T2-weighted FSE and FLAIR-HASTE imaging.

CONCLUSION

FLAIR-HASTE is considered to be an effective sequence for differentiating hepatic cysts from liver metastases without the use of a contrast agent. With FLAIR-HASTE one can confidently diagnose small hepatic lesions found on CT in patients with a malignancy.

Differentiation between hepatic cyst and hemangioma: Additive value of breath-hold, multisection fluid-attenuated inversion-recovery magnetic resonance imaging using half-Fourier acquisition single-shot turbo-spin-echo sequence

PURPOSE

To evaluate the additive value of breath-hold, multisection fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) using half-Fourier acquisition single-shot turbo-spin-echo (HASTE) sequence as supplements to moderately and heavily T2-weighted fast-spin-echo (FSE) sequences in differentiating hepatic cyst from hemangioma.

MATERIALS AND METHODS

A total of 183 lesions (127 hepatic cysts, 56 hepatic hemangiomas) in 117 patients were evaluated in this study. Three radiologists independently reviewed FLAIR MR images using a HASTE sequence and T2-weighted FSE MR images. Each radiologist used a five-point scale to rate his confidence in determination of hepatic cyst and hemangioma.

RESULTS

All three reviewers were significantly better able to differentiate hepatic cyst from hepatic hemangioma with the combination of FLAIR imaging using HASTE and moderately and heavily T2-weighted FSE images (area under the receiver operating characteristic (ROC) curve, 0.99 for each reader) than with moderately and heavily T2-weighted FSE images alone (0.82-0.93; P < 0.05). FLAIR-HASTE imaging in addition to T2-weighted FSE sequences improved the diagnostic performance, including the sensitivity, specificity, accuracy, and confident diagnosis in the differentiation between hepatic hemangiomas and cysts.

CONCLUSION

FLAIR-HASTE imaging is useful for distinguishing hepatic hemangioma from hepatic cyst without the use of contrast-enhanced MR images.