T2* gradient echoes

Figure 2.2.14 shows cross-sections of salmon acquired with a gradient echo sequence (TR = 30 ms, TE = 15 ms, slice thickness = 4 cm, image matrix = 128 x 128, total acquisition time = 3.84 s). For the female salmon, roe were clearly visualized as dark regions because the T2 is shorter than that of the surrounding tissues. For the male salmon, milt was observed instead of roe. However, the image intensity of the milt was similar to that of the surrounding tissues. 

For PI, basically all fast and strongly T2 w sequences can be used. In the early days of PI, measurements were performed using fast, T2 w gradient-echo sequences, particularly the fast low angle shot... 

Kinoshita T, Okudera T, Tamura H et al (2000) Assessment of lacunar hemorrhage associated with hypertensive stroke by echo-planar gradient-echo T2 -weighted MRI. Stroke 31 1646-1650... 

Tsushima Y, Aoki J, Endo K (2003) Brain microhemorrhages detected on T2 -weighted gradient-echo MR images. AJNR Am J Neuroradiol 33 88-96... 

Fig. 13.5. T2 -weighted gradient echo images in a patient with biopsy proven cerebral amyloid angiopathy (CAA). Extensive low signal abnormality is noted on the brain surfaces and in the parenchyma indicating the previous hemorrhages. Periventricular high intensity lesions, a common finding in CAA is also noted...

Fig. 13.6. FLAIR (top row) and T2 -weighted gradient echo images (bottom row) in a patient with hypertension showing a typical lesion pattern. Note subcortical lesions including lacunar lesions with severe tissue destruction and CSF like, low signal intensity (e.g. lateral to the anterior horn of the left lateral ventricle) on FLAIR images. On T2 -weighted images residuals from hemorrhagic lesions and small bleeds are appreciated mainly in the basal ganglia...

Our typical MR protocol for suspected CVST includes an axial FLAIR, axial diffusion-weigh ted MRI, coronal T1 SE and T2 TSE sequences, a coronal gradient echo and a 3D phase contrast venous angiogram with a total imaging time of approximately 20 min. 

Nighoghossian N, Hermier M, Adeleine P et al. (2002). Old microbleeds are a potential risk factor for cerebral bleeding after ischemic stroke a gradient-echo T2-weighted brain MRI study. Stroke 33 735-742. 

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