Coronal Short Tau Inversion Recovery Research Articles

Magnetic resonance imaging in the assessment of cervical nodal metastasis in oral squamous cell carcinoma

OBJECTIVE: The accurate pre-operative assessment of cervical lymph nodes is a well recognized problem in the management of patients with oral squamous cell carcinoma. Imaging techniques have improved the accuracy of staging but cannot determine if nodal enlargement is due to reactive changes or malignant involvement. We assessed the diagnostic performance of magnetic resonance imaging (MRI) in detecting metastatic disease within the neck in oral cancer patients. MATERIALS AND METHODS: A retrospective study was performed on 58 patients treated for oral squamous cell carcinoma. All patients had pre-operative MR imaging including axial and coronal short tau inversion recovery (STIR) sequences and pre- and post-gadolinium axial TI weighted sequences. Nineteen patients had bilateral neck dissections giving 77 sides of neck for study. MR images were reviewed for nodal involvement at each anatomical level within the neck and correlated with findings at histology. RESULTS: Twenty-seven of the 77 sides of neck contained histologically positive nodes (35.1 %). MRI sensitivity was 66.7 % and specificity 68 %. There was a false-negative rate of 20.9 % and false-positive rate of 47.1 %. Some enlarged, histologically positive nodes were not detected by MRI. Furthermore, in five cases the only histological evidence of nodal malignancy was the presence of a micrometastasis (<3 mm tumour deposit). MRI detected two of these. CONCLUSION: MRI lacks sufficient sensitivity and specificity to replace elective neck dissection for both staging and prognostic purposes.

Throwing injury of the elbow: assessment with gradient three-dimensional, fourier transform gradient-echo and short tau inversion recovery images.

We assessed MR findings of throwing injuries occurring in the elbow joint using three-dimensional Fourier transform (3DFT) and short tau inversion recovery (STIR) images. MR images of 63 elbows in 63 male patients aged from 10 to 32 years (mean age, 15 years 11 months) suffering from throwing injury were visually analyzed. The sequences used for the study were axial 3DFT and coronal STIR. Full-thickness tears were demonstrated in 34 elbows and undersurface tears of the ulnar collateral ligament (UCL) were demonstrated in five elbows. Thirty loose bodies were detected in 14 elbows. Cartilaginous damage due to osteochondral injury was depicted in 21 elbows. Multiplanar reformatted images using the 3DFT data set were useful for assessing torn UCLs, intraarticular loose bodies, and capitellar fragments. Full-thickness tears and undersurface tears of the UCL could be differentiated with STIR images. 3DFT and STIR sequences depict various aspects of throwing injuries occurring in the elbow.

Short tau inversion recovery magnetic resonance imaging in occult scaphoid injuries: Effect on management

Over a 21-month period, 16 patients with possible scaphoid fractures, where conventional radiographs were essentially normal on the day of injury and 10 days later, were examined by coronal short tau inversion recovery (STIR) and T1 weighted sequences on a 0.2 Tesla scanner. The magnetic resonance (MR) examinations were done in between electively booked patients and management was altered in 50% of patients. It was expedient to do MR as radio-isotope facilities were not available at the hospital. In four patients, the examination was entirely normal. In another four patients, intercarpal fluid collections only were demonstrated (two generalized and two localized). In these patients a plaster cast was not re-applied. In two patients, bony injuries of the distal radius were demonstrated instead, with the scaphoid being normal. In the remaining six patients, variable appearances were shown, ranging from an actual fracture line demonstrated on both STIR and T1-weighted images with the remainder of the scaphoid being hyperintense on STIR and hypointense on T1, to non-visualization of the actual fracture line, which appeared to be represented by a much more hyperintense band through the waist of an otherwise hyperintense scaphoid on the STIR sequence. In all these patients a plaster cast was re-applied empirically, including those patients with a definite fracture and those patients with apparent bone contusion only. Although the T1-weighted images were anatomically superior, their addition did not alter management and it is suggested that coronal STIR images should suffice to demonstrate occult fractures of the scaphoid.

Longitudinal stress fractures of the tibia: MRI features in two cases

Longitudinal stress fractures of the tibia are a recognized but unusual finding in long distance runners. Two cases are presented in which the diagnosis on plain films and scintigraphy (in one case) was not evident. Both patients were referred for MRI. Coronal short tau inversion recovery (STIR) sequences demonstrated extensive hyperintense longitudinal intramedullary signal changes in the tibia. T1-weighted spin-echo scans showed corresponding but less extensive regions of reduced signal intensity. In one case, enhancement of this area was seen following i.v. dimeglumine-gadopentetate (Gd-DTPA). Adjacent soft-tissue abnormality and periosteal reaction was seen in one case but in neither patient was a fracture line identified. Thin section CT with sagittal reformats demonstrated an irregular intracortical longitudinal lucent fracture line which was distinct from the nutrient foramen, establishing the diagnosis.

Magnetic resonance imaging of septic sacroiliitis

Five cases of septic sacroiliitis diagnosed by magnetic resonance imaging (MRI) are presented. Imaging was performed between 2 and 14 days after onset of symptoms and consisted of varying combinations of coronal short tau inversion recovery (STIR), axial T2-weighted spin echo (SE), and coronal and axial pre- and postcontrast T1-weighted SE scans. Abnormalities included demonstration of sacroiliac joint effusions, bone oedema and adjacent inflammation as high signal on STIR and T2-weighted SE scans, and identification of abscesses in two cases as rim-enhancing lesions anterior to the joint on gadolinium-enhanced T1-weighted SE scans. The role of MRI and other forms of imaging in septic sacroiliitis is discussed.