Brain hemorrhage: evaluation with fast spin-echo and conventional dual spin-echo images.

Abstract

Signal intensity of blood products on proton-density- and T2-weighted images obtained with spin-echo (SE) and fast SE (FSE) sequences was evaluated in 15 patients with central nervous system hemorrhage to determine the extent of differences between the two techniques when signal loss from magnetic susceptibility effects in hemorrhagic lesions is considered. Within operator-defined regions of interest, signal intensity of hemorrhage, iron-containing nuclei, white matter, scalp fat, and noise was measured along the phase-encoding direction. Hemosiderin, deoxyhemoglobin, and iron-containing nuclei had slightly higher signal intensity on FSE images than on SE images, but the differences were not statistically significant. Signal intensity of methemoglobin was similar with both sequences, whereas that of scalp fat was higher on FSE images. Signal intensity measurements for most tissues studied were comparable, but the signal-to-noise ratios with FSE imaging were less than those with SE imaging. Although paramagnetic blood products may show slightly higher signal intensity with FSE imaging, contrast with the two sequences was comparable and lesion conspicuity was nearly identical.

Improved Delineation of Ventricular Shunt Catheters Using Fast Steady-State Gradient Recalled-Echo Sequences in a Rapid Brain MR Imaging Protocol in Nonsedated Pediatric Patients

“…11,12,14 The drawback to these sequences, however, is that the multiple 180°radio-frequency pulses and the short echo spacing result in a reduced sensitivity to susceptibility effects. [9][10][11][12]14 GRE images have been shown to be more sensitive in the detection of blood products than fast single-shot TSE-T2 sequences.…”

“…Both techniques enable application of a shorter TR compared with standard GRE sequences. [9][10][11][12]14,15,16 The SS-GRE sequences can be further subdivided into 2 categories when it is remembered that the resultant steady-state precession signal intensity is composed of both FID and spin-echo components. The fast SS-GRE sequence used in our rapid nonsedated pediatric brain protocol is the variety that samples the FID (hence the increased conspicuity of susceptibility effects).…”

“…These sequences are known to be more sensitive to the susceptibility effects of blood products. 9,10 To our knowledge, the utility of these sequences in catheter delineation has not been previously reported. Because these sequences are additions to a brain protocol that necessitates a short scanning time, rapid SS-GRE sequences are preferred over the standard GRE sequences with longer TRs.…”

“…One is the lack of sensitivity in identification of extra-axial and parenchymal blood products. 9,10 The other is decreased catheter delineation compared with CT. 8 One possible remedy to the problem is the addition of GRE sequences to supplement the standard single-shot TSE-T2 sequences of rapid nonsedated pediatric brain MR imaging protocols. These sequences are known to be more sensitive to the susceptibility effects of blood products.…”

Radiation Risk Due to Shunted Hydrocephalus and the Role of MR Imaging–Safe Programmable Valves

“…29,30 The other is decreased catheter delineation compared with CT. 28 Rapid steady state gradient recalled echo scanning has been advocated to eliminate the problems associated with rapid brain MR imaging by using fast TSE T2 sequences. 31 A common concern with shunt function is the over-or underdrainage resulting from the mismatch of opening pressure of the valve to the needs of the patient.…”