Heavily T2W 3D-SPACE images for evaluation of cerebrospinal fluid containing spaces.

Dear Sir,

We read with great interest the review paper written by Hingwala et al. entitled “Applications of 3D CISS sequence for problem solving in neuroimaging”.[1] While we agree with all the statements made by Hingwala et al. about the three-dimensional constructive interference in steady state (3D-CISS) sequence usage, we want to also emphasize the usefulness of a recently developed sequence three-dimensional sampling perfection with application-optimized contrasts using different flip angle evolution (3D-SPACE) that deserves to be comprehensively evaluated.

Recently, with the introduction of 3 T MRI scanners, there has been a significant increase in the quality and spatial resolution of images.[2] 3D-SPACE images are obtained with a different flip-angle (FA) mode technique. It allows volumetric acquisition of the whole brain with thin slices and isotropic voxels within a reasonable time period.[3] Using 3D-SPACE, which is a turbo spin-echo variant, one can obtain heavily T2W images as well as T1W, T2W, or FLAIR images.[45] The most important advantage of this sequence is that it can provide very thin and high-resolution three planes or oblique reformatted slices (such as 0.7 × 0.7 × 0.7 mm) with the help of isotropic acquisition.[3]

In our department, over the last 2 years, we have preferred to obtain heavily T2W 3D-SPACE images for the indications mentioned by Hingwala et al.[1] An important feature of this sequence is that unlike other heavily T2W sequences, it does not create a significant artifact (such as the banding artifact) and, moreover, it enables scanning of the whole brain or the spinal canal with a single acquisition. This is very useful for proper evaluation of the images and helps the radiologist assess the brain and spine comprehensively.

For a better understanding of this technique, we present heavily T2W 3D-SPACE images and the acquisition parameters of the T2W 3D-SPACE images of two patients in Figure 1 and Table 1, respectively.

Figure 1

(A–F) Heavily T2W 3D-SPACE images of a 43-year-old man (normal volunteer; A) and 30-year-old man (patient with hydrocephalus and aqueductal stenosis; B–F). Sagittal image of the patient with hydrocephalus demonstrates complete aqueductal stenosis and an aqueductal web (arrow in B). Axial (D) and coronal (F) thin-section (0.8 mm) reformatted images obtained from the sagittal 3D-SPACE images (C and E, respectively) show ventriculomegaly

Table 1

Acquisition parameters of heavily T2W 3D-SPACE images in our department

In conclusion, in departments that have 3 T MRI scanners, we recommend that heavily T2W isotropic images be obtained by using a different FA-mode technique (such as 3D-SPACE) for the evaluation of cerebrospinal fluid (CSF) containing spaces. There is a need for comprehensive studies to compare the 3D-SPACE technique described above with the other heavily T2W sequences.