USEFULNESS OF A HALF‐FOURIER ACQUISITION SINGLE‐SHOT TURBO SPIN‐ECHO PULSE SEQUENCE IN IDENTIFYING ARACHNOID DIVERTICULA IN DOGS

Abstract

Single-shot turbo spin-echo sequences are heavily T2-weighted sequences that are exceptionally well suited to evaluate the subarachnoid space. In the T2-weighted fast spin-echo sequences that are used routinely in spinal magnetic resonance (MR) imaging, the subarachnoid space is not well differentiated from the surrounding epidural fat, which could lead to decreased detection of lesions of the subarachnoid space such as arachnoid diverticula. Our purpose was to determine the added value of a single-shot turbo spin-echo sequence in identifying cystic lesions of the subarachnoid space in dogs. MR images of six dogs with a confirmed arachnoid diverticulum and 24 dogs with other spinal disease were included. Six observers were asked to interpret only T2-weighted images initially, and in a second session, T2-weighted and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. The MR images were anonymized, and no signalment, history, or clinical information was provided. Without the HASTE sequences, 25% of arachnoid diverticula were identified. Adding the HASTE sequence increased the diagnosis of arachnoid diverticulum to 52.8%. The resulting difference, after adding the HASTE sequence, of 27.8% was statistically significant (P = 0.002). No false-positive diagnoses of arachnoid diverticulum were made with either sequence. Although sensitivity in this study was likely artificially low, the significantly increased detection rate of arachnoid diverticula when using HASTE imaging indicates that this sequence is a valuable addition to MR imaging protocols for the canine spine.

Thoracolumbar Intradural Disc Herniation in Eight Dogs: Clinical, Low‐field Magnetic Resonance Imaging, and Computed Tomographic Myelography Findings

“…Retrospectively, readers for the current study reported that the T2WI hyperintense lesions seen in cases 1–3 seemed to be the “golf tee sign,” although this information was not available to surgeons before surgery. A “golf tee sign” can be theoretically differentiated from other conditions by using a combination of T2WI, T2*WI, fluid‐attenuated inversion recovery (FLAIR), and pre‐ and post‐contrast T1WI, as well as the single‐shot turbo spin echo sequence or half‐Fourier acquisition single‐shot turbo spin‐echo pulse sequence . However, differentiation of these lesions using low‐field MRI is not easy in the canine vertebral canal due to the smaller size vs. humans.…”

“…A "golf tee sign" can be theoretically differentiated from other conditions by using a combination of T2WI, T2 * WI, fluid-attenuated inversion recovery (FLAIR), and pre-and post-contrast T1WI, [16][17][18] as well as the single-shot turbo spin echo sequence or half-Fourier acquisition single-shot turbo spin-echo pulse sequence. 20,21 However, differentiation of these lesions using low-field MRI is not easy in the canine vertebral canal due to the smaller size vs. humans. The image spatial resolution and contrast in T2 * WI varies with the field strength because of variations in signal-tonoise ratios.…”

Mri Characteristics of Fourth Ventricle Arachnoid Diverticula in Five Dogs

“…MRI was therefore unable to identify the cause of the obstructive hydrocephalus. Recently, half‐fourier acquisition single‐shot turbo spin‐echo pulse (HASTE) sequences, which are heavily T2‐weighted sequences, have been proven to increase the sensitivity of MRI for diagnosis of spinal arachnoid diverticula . These MRI sequences were not available at the time of investigations of our cases and studies evaluating the usefulness of HASTE sequences for diagnosis of intracranial arachnoid diverticula are lacking.…”

Extramedullary Spinal Cysts in Dogs

“…The names refer to a single condition characterized by an accumulation of CSF and dilation of a focal area of the meninges, with most being congenital (primary), although some may be acquired (secondary). We use the most recent but anatomically correct term of Intradural arachnoid diverticulum …”

“…An advantage over other imaging modalities is the ability to detect the presence of adhesions and septations, although this is not used as a diagnostic procedure . MRI is now the procedure of choice for the diagnosis of a spinal intradural arachnoid diverticulum (Figs and ), with a recent study suggesting the addition of a single‐shot turbo spin‐echo sequence gives a more than twofold increase in spinal intradural arachnoid diverticulum detection compared to a T2‐weighted sequence alone . However, the addition of a single‐shot turbo spin‐echo sequence only decreased the false negatives from 75% to 47.2%, meaning that some diverticulae went undetected.…”