T1 Spin-echo Sequences Research Articles

Clinical feasibility of post-contrast accelerated 3D T1-Sampling Perfection with Application-optimized Contrasts using different flip angle Evolutions (SPACE) with iterative denoising for intracranial enhancing lesions: a retrospective study.

Post-contrast T1-Sampling Perfection with Application-optimized Contrasts using different flip angle Evolutions (SPACE) is the preferred 3D T1 spin-echo sequence for evaluating brain metastases, regardless of the prolonged scan time. To evaluate the application of accelerated post-contrast T1-SPACE with iterative denoising (ID) for intracranial enhancing lesions in oncologic patients. For evaluation of intracranial lesions, 108 patients underwent standard and accelerated T1-SPACE during the same imaging session. Two neuroradiologists evaluated the overall image quality, artifacts, degree of enhancement, mean contrast-to-noise ratiolesion/parenchyma, and number of enhancing lesions for standard and accelerated T1-SPACE without ID. Although there was a significant difference in the overall image quality and mean contrast-to-noise ratiolesion/parenchyma between standard and accelerated T1-SPACE without ID and accelerated SPACE with and without ID, there was no significant difference between standard and accelerated T1-SPACE with ID. Accelerated T1-SPACE showed more artifacts than standard T1-SPACE; however, accelerated T1-SPACE with ID showed significantly fewer artifacts than accelerated T1-SPACE without ID. Accelerated T1-SPACE without ID showed a significantly lower number of enhancing lesions than standard- and accelerated T1-SPACE with ID; however, there was no significant difference between standard and accelerated T1-SPACE with ID, regardless of lesion size. Although accelerated T1-SPACE markedly decreased the scan time, it showed lower overall image quality and lesion detectability than the standard T1-SPACE. Application of ID to accelerated T1-SPACE resulted in comparable overall image quality and detection of enhancing lesions in brain parenchyma as standard T1-SPACE. Accelerated T1-SPACE with ID may be a promising replacement for standard T1-SPACE.

From Dose Reduction to Contrast Maximization: Can Deep Learning Amplify the Impact of Contrast Media on Brain Magnetic Resonance Image Quality? A Reader Study.

The aim of this study was to evaluate a deep learning method designed to increase the contrast-to-noise ratio in contrast-enhanced gradient echo T1-weighted brain magnetic resonance imaging (MRI) acquisitions. The processed images are quantitatively evaluated in terms of lesion detection performance. A total of 250 multiparametric brain MRIs, acquired between November 2019 and March 2021 at Gustave Roussy Cancer Campus (Villejuif, France), were considered for inclusion in this retrospective monocentric study. Independent training (107 cases; age, 55 ± 14 years; 58 women) and test (79 cases; age, 59 ± 14 years; 41 women) samples were defined. Patients had glioma, brain metastasis, meningioma, or no enhancing lesion. Gradient echo and turbo spin echo with variable flip angles postcontrast T1 sequences were acquired in all cases. For the cases that formed the training sample, "low-dose" postcontrast gradient echo T1 images using 0.025 mmol/kg injections of contrast agent were also acquired. A deep neural network was trained to synthetically enhance the low-dose T1 acquisitions, taking standard-dose T1 MRI as reference. Once trained, the contrast enhancement network was used to process the test gradient echo T1 images. A read was then performed by 2 experienced neuroradiologists to evaluate the original and processed T1 MRI sequences in terms of contrast enhancement and lesion detection performance, taking the turbo spin echo sequences as reference. The processed images were superior to the original gradient echo and reference turbo spin echo T1 sequences in terms of contrast-to-noise ratio (44.5 vs 9.1 and 16.8; P < 0.001), lesion-to-brain ratio (1.66 vs 1.31 and 1.44; P < 0.001), and contrast enhancement percentage (112.4% vs 85.6% and 92.2%; P < 0.001) for cases with enhancing lesions. The overall image quality of processed T1 was preferred by both readers (graded 3.4/4 on average vs 2.7/4; P < 0.001). Finally, the proposed processing improved the average sensitivity of gradient echo T1 MRI from 88% to 96% for lesions larger than 10 mm ( P = 0.008), whereas no difference was found in terms of the false detection rate (0.02 per case in both cases; P > 0.99). The same effect was observed when considering all lesions larger than 5 mm: sensitivity increased from 70% to 85% ( P < 0.001), whereas false detection rates remained similar (0.04 vs 0.06 per case; P = 0.48). With all lesions included regardless of their size, sensitivities were 59% and 75% for original and processed T1 images, respectively ( P < 0.001), and the corresponding false detection rates were 0.05 and 0.14 per case, respectively ( P = 0.06). The proposed deep learning method successfully amplified the beneficial effects of contrast agent injection on gradient echo T1 image quality, contrast level, and lesion detection performance. In particular, the sensitivity of the MRI sequence was improved by up to 16%, whereas the false detection rate remained similar.

The Assessment of Brain Volume Differences in Idiopathic Central Precocious Puberty Girls; Comparison of Age-Matched Girls and Normal Puberty Girls.

Objective: Although there have been several studies on the neuroanatomical changes in idiopathic central precocious puberty (ICPP), the association between each brain region and ICPP has not yet been clearly elucidated. This study aimed to evaluate the difference in brain structure in ICPP compared with age-matched healthy controls and normal puberty controls, and additionally the correlation between brain volume difference and the luteinizing hormone (LH). Materials and Methods: The study enrolled fifteen girls with ICPP, as well as 15 age-matched healthy girls and 15 normal puberty girls as controls. The subjects underwent a 1.5 Tesla Avanto MR Scanner. Anatomical T1-weighted images were acquired with a T1 spin-echo sequence. The volumes of total and regional brain were compared with each of the two control groups and analyzed through the paired T-test, and the brain region related to the peak LH level was also analyzed through a simple correlation test. Results: The mean age of the ICPP group, age-matched group, and puberty group were 8.0 ± 0.9 years, 7.8 ± 0.9 years, and 11.9 ± 0.9 years, respectively. In our findings, the regional cerebral volumes in ICPP were different from age-matched controls. Compared with controls, ICPP showed a significant increase in gray matter (GM) volumes (the medial prefrontal cortex, superior parietal gyrus, supramarginal gyrus, angular gyrus, postcentral gyrus, superior occipital gyrus, cuneus, hippocampus, parahippocampal gyrus, posterior cingulate gyrus (PCgG), cerebellar cortex (Cb)) and in white matter (WM) volumes (the insular, caudate, splenium of corpus callosum (p < 0.001)). Especially, the GM volumes of the PCgG (r = 0.57, p = 0.03) and Cb (r = 0.53, p = 0.04) were correlated positively with LH concentrations stimulated by the gonadotropin-releasing hormone agonist. Compared to the normal puberty control, no significant difference in GM volume was found. Conclusions: This study showed the overall brain volumetric differences between ICPP girls and age-matched controls using voxel-based morphometric analysis, and further showed the correlation between brain volume and the sex hormone in ICPP. Through a comparison between the two groups, the cerebral development pattern of ICPP is similar to that of normal puberty, and these local differences in cerebral volume may affect social and congenital changes. These findings will be useful for understanding the neuroanatomical mechanisms on the specific morphological variations associated with ICPP.

Fast magnetic resonance arthrography of the labrum

Research question: Short volumetric interpolated breath hold exam (VIBE) 3D gradient echo sequences are comparable to T1 spin echo (SE) sequences for evaluating the shoulder labrum using arthroscopy as a gold standard. Methods: 24 patients with suspected labral tears had magnetic resonance (MR) arthrography of the shoulder using 1.5T MR scanner. Coronal oblique 3D VIBE FS sequences were performed and reconstructed in axial and sagittal oblique planes and compared with standard T1 SE sequences. Presence and location of labral tear and rotator cuff tears were noted. Findings were correlated with surgery where available. Time to obtain T1 SE sequences versus 3D VIBE acquisition was recorded. Results: Of 24 patients, 54% had arthroscopy. Sensitivity and positive predictive value (PPV) of both T1 SE and VIBE sequences for labral tears was 92%. 100% agreement for diagnosis of labral tear by readers between both sequences was noted. Specific labral tear location was accurate in 75% for both sequences. The mean time to obtain T1 SE sequences was 13.5 mins and 7.5 minutes for 3D VIBE sequences. Conclusion: Fast MR arthrography using 3D VIBE sequences shows excellent concordance with standard T1-FS sequence for diagnosis of labral tears. With shorter acquisition time and high diagnostic sensitivity 3D VIBE sequences maybe used as an alternative to standard sequences. Level of evidence: Level III retrospective diagnostic study.

Three-Dimensional Magnetic Resonance Imaging Volumetry of Radial Forearm Flap Reconstructions After Craniomaxillofacial Tumor Resection.

Oral cancer is a common and life threatening disease that requires interdisciplinary treatment and often necessitates complex facial reconstruction. Standard care includes tumor resection, while reconstruction is routinely performed with free radial forearm flaps. As esthetic results are crucial for quality of life, flap size, flap volume, and flap composition have to be considered. To date no standardized measurement of flap volume and shrinkage has been established for routine use. The purpose of this study was therefore to evaluate the transplant volume of radial forearm flaps in craniomaxillofacial reconstruction using magnetic resonance imaging (MRI) volumetry. Ten postoperative MR sequences of 5 patients were included. All patients had received transplantation of radial forearm flaps after tumor resection and radiation therapy. Evaluated parameters were: sex, age, type of flap, flap volume. Two different observers (1 surgeon and 1 radiologist) segmented transplant volume at three different time points in a postoperative MRI independently and in consensus, using both axial and coronal slices. A nonfat saturated T1 spin echo sequence was used. Mean transplant volume was calculated. A total of 90 volumetric measurements were included. Overall Tvolm was 24.83 cm from axial sections and 27.25 cm from coronal sections. Measurements for axial and coronal orientations differed significantly. Results showed excellent intra- and inter-rater correlation, coefficient for rater A and rater B were 0.91 (axial) and 0.96 (coronal). MRI volumetry is a noninvasive reproducible method to quantify volume of free radial forearm flaps in situ but should follow specific considerations for best results.

T1 inversion recovery pulse sequence: could it replace T1 spin echo sequence in neuroimaging by improving tissue contrast?

BackgroundT1 inversion recovery (T1IR) sequence improved tissue contrast by providing higher gray matter-white matter contrast ratio (GM-WM contrast ratio) and higher lesion contrast noise ratio (CNR). This study aims to highlight its significance in the evaluation of space-occupying lesions whether intra-axial or extra-axial and also in multiple sclerosis (MS) by comparing it with T1 spin echo (T1SE) sequence.ResultIn a total of 50 patients, 14 patients with extra-axial lesions, 18 patients with intra-axial lesions, and 18 patients with multiple sclerosis were included. The CNR was significantly higher for pre-contrast T1IR images than for pre-contrast T1SE (− 13.04 (1.20) vs − 7.73 (0.70); p value < 0.01). After giving intravenous contrast media, CNR in T1SE was higher than T1IR (11.14 (1.75) vs 9.41 (1.83)) without statistical significance (p value = 0.19) and CNR was higher in T1IR than T1SE in lesions with low enhancement ratio (ER). As well, the overall number of lesions was higher on T1IR especially in MS (10.67 (2.26) vs 3.89 (1.05); p value < 0.01).ConclusionOn pre-contrast sequences, T1IR could be used as an added sequence in most brain lesions giving higher lesion CNR. After giving intravenous contrast media, T1IR could be used in lesions with low ER. It also could be used in situations in which gadolinium injection is contraindicated and also could be used in follow-up of MS patient by detecting a higher number of lesions that can be easily missed in T1SE.

Improving acute demyelinating lesion detection: which T1-weighted magnetic resonance acquisition is more sensitive to gadolinium enhancement?

Because of the need for a standardized and accurate method for detecting multiple sclerosis (MS) inflammatory activity, different magnetic resonance (MR) acquisitions should be compared in order to choose the most sensitive sequence for clinical routine. To compare the sensitivity of a T1-weighted image to a single dose of gadolinium (Gd) administration both with and without magnetization transfer to detect contrast enhancement in active demyelinating focal lesions. A sample of relapsing-remitting MS patients were prospectively examined separately by two neuroradiologists using a 1.5 Tesla scanner. The outcome parameters were focused on Gd-enhancement detection attributed to acute demyelination. All MR examinations with at least one Gd-enhancing lesion were considered positive (MR+) and each lesion was analyzed according to its size and contrast ratio. Thirty-six MR examinations were analyzed with a high inter-observer agreement for MR+ detection (k coefficient > 0.8), which was excellent for the number of Gd-enhancing lesions (0.91 T1 spin-echo (SE), 0.88 T1 magnetization transfer contrast (MTC) sequence and 0.99 magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Significantly more MR+ were reported on the T1 MTC scans, followed by the T1 SE, and MPRAGE scans. Confidently, the T1 MTC sequence demonstrated higher accuracy in the detection of Gd-enhancing lesions, followed by the T1 SE and MPRAGE sequences. Further comparisons showed that there was a statistically significant increase in the contrast ratio and area of Gd-enhancement on the T1 MTC images when compared with both the SE and MPRAGE images. Single-dose Gd T1 MTC sequence was confirmed to be the most sensitive acquisition for predicting inflammatory active lesions using a 1.5 T magnet in this sample of MS patients.

Prognostic Implications of Gadolinium Enhancement of Skull Base Chordomas.

Skull base chordomas often demonstrate variable MR imaging characteristics, and there has been limited prior research investigating the potential clinical relevance of this variability. The purpose of this retrospective study was to assess the prognostic implications of signal intensity on standard imaging techniques for the biologic behavior of skull base chordomas. Medical records were retrospectively reviewed for 22 patients with pathologically confirmed skull base chordomas. Clinical data were recorded, including the degree of surgical resection, the presence or absence of radiation therapy, and time to progression/recurrence of the tumor or time without progression/recurrence of the tumor following initial treatment. Pretreatment imaging was reviewed for the presence or absence of enhancement and the T2 signal characteristics. Tumor-to-brain stem signal intensity ratios on T2, precontrast T1, and postcontrast T1 spin-echo sequences were also calculated. Statistical analysis was then performed to assess correlations between imaging characteristics and tumor progression/recurrence. Progression/recurrence of skull base chordomas was seen following surgical resection in 11 of 14 (78.6%) patients with enhancing tumors and in zero of 8 patients with nonenhancing tumors. There was a statistically significant correlation between skull base chordoma enhancement and subsequent tumor progression/recurrence (P < .001), which remained significant after controlling for differences in treatment strategy (P < .001). There was also a correlation between postcontrast T1 signal intensity (as measured by postcontrast T1 tumor-to-brain stem signal intensity ratios) and recurrence/progression (P = .02). While T2 signal intensity was higher in patients without tumor progression (median tumor-to-brain stem signal intensity ratios on T2 = 2.27) than in those with progression (median tumor-to-brain stem signal intensity ratios on T2 = 1.78), this association was not significant (P = .12). Enhancement of skull base chordomas is a risk factor for tumor progression/recurrence following surgical resection.

The use of gadolinium-containing medium dilutions in evaluations of pathological changes in magnetic resonance images of the canine elbow

The aim of this study was to evaluate the usefulness of the paramagnetic gadolinium-containing contrast agent, diluted 1:800, in evaluations of pathological changes in the canine elbow joint. The experiment was performed on 6 large breed dogs of both sexes with a body weight of 25 to 40 kg. Thoracic limb lameness and pain in the elbow joint area were observed in all patients. The animals were subjected to standard physical examinations, radiography and low-field magnetic resonance imaging scans with the use of a contrast agent. The Spin Echo T1 dorsal sequence as well as 3D SST1 transverse and XBONE T1 transverse sequences were highly effective in diagnosing osteochondritis dissecans (OCD) of the medial humeral condyle. Degenerative changes and the fragmented coronoid process (FCP) of the ulna were very well visualized by High Resolution Gradient Echo, XBONE T2 and Spin Echo T1 sequences in the sagittal plane. The administration of the gadolinium contrast agent, diluted 1:800, to the elbow joint cavity enhances the diagnostic value of magnetic resonance images in evaluations of medial compartment disease, in particular fragmentation of the medial coronoid process.

Tracking the Evolution of Cerebral Gadolinium-Enhancing Lesions to Persistent T1 Black Holes in Multiple Sclerosis: Validation of a Semiautomated Pipeline.

Some gadolinium-enhancing multiple sclerosis (MS) lesions remain T1-hypointense over months ("persistent black holes, BHs") and represent areas of pronounced tissue loss. A reduced conversion of enhancing lesions to persistent BHs could suggest a favorable effect of a medication on tissue repair. However, the individual tracking of enhancing lesions can be very time-consuming in large clinical trials. We created a semiautomated workflow for tracking the evolution of individual MS lesions, to calculate the proportion of enhancing lesions becoming persistent BHs at follow-up. Our workflow automatically coregisters, compares, and detects overlaps between lesion masks at different time points. We tested the algorithm in a data set of Magnetic Resonance images (1.5 and 3T; spin-echo T1-sequences) from a phase 3 clinical trial (n = 1,272), in which all enhancing lesions and all BHs had been previously segmented at baseline and year 2. The algorithm analyzed the segmentation masks in a longitudinal fashion to determine which enhancing lesions at baseline turned into BHs at year 2. Images of 50 patients (192 enhancing lesions) were also reviewed by an experienced MRI rater, blinded to the algorithm results. In this MRI data set, there were no cases that could not be processed by the algorithm. At year 2, 417 lesions were classified as persistent BHs (417/1,613 = 25.9%). The agreement between the rater and the algorithm was > 98%. Due to the semiautomated procedure, this algorithm can be of great value in the analysis of large clinical trials, when a rater-based analysis would be time-consuming.

Direct magnetic resonance arthrography of the canine elbow

This study compares the effects of four dilutions of the gadolinium-containing contrast media (1:100; 1:400; 1:800; 1:1,200) administered to the elbow on the quality of magnetic resonance images. All the examined dilutions had a positive effect on image quality, and 1:800 was regarded as the optimal dilution of gadolinium for viewing the elbow because it imparted good contrast to the joint cavity without obliterating the contours of articular surfaces. Transverse, sagittal, and dorsal low-field magnetic resonance images were obtained in 24 canine cadaver front limbs. The musculus biceps brachii, m. triceps brachii, m. extensor carpi radialis, m. flexor carpi ulnaris, the articular surfaces, the medial coronoid process and the anconeal process of the ulna were well visualized by High Resolution Gradient Echo, XBONE T2 and Spin Echo T1 sequences in the sagittal plane. The biceps brachii, pronator teres, flexor carpi radialis, extensor digitorum communis, extensor carpi radialis, deltoid muscle and the articular surface of the medial condyle of the humerus were very well visualized by 3D SST1 and XBONE T2 sequences in the transverse plane. The triceps brachii muscle, extensor digitorum lateralis muscle, superficial digital flexor, deep digital flexor and the medial condyle of the humerus were very well visualized by the Spin Echo T1 sequence in the dorsal plane. This article describes for the first time the use of the gadolinium contrast agent administered to the canine elbow joint during magnetic resonance modality. Magnetic resonance arthrography can be a helpful visualization technique in treating canine soft tissue elbow injury.

Comparison of high resolution gradient echo, XBONE T1, XBONE T2, Spin Echo T1 and 3D SST1 magnetic resonance imaging sequences for imagining the canine elbow.

Twenty canine elbows were examined by low-field MRI. The objective of this study was to compare five magnetic resonance sequences: High Resolution Gradient Echo in the sagittal plane, XBONE T2 in the sagittal plane, Spin Echo T1 in the sagittal plane, Spin Echo T1 in the dorsal plane and 3D SST1 and XBONE T1 in the transverse plane, and to determine which sequences have the highest diagnostic value in imagining the canine elbow. High Resolution Gradient Echo, XBONE T2 and Spin Echo T1 sequences in the sagittal plane proved to be very useful in evaluations of osseous structures such as the medial coronoid process, the anconeal process of the ulna and joint surfaces. The above sequences facilitate evaluations of radial extensor muscle of the wrist, biceps brachii muscle, triceps brachii muscle and the flexor carpi ulnaris muscle. 3D SST1 and XBONE T1 sequences in the transverse plane produce high-quality images of the medial humeral condyle and surfaces of the elbow joint. Those sequences are also useful for evaluating the surrounding muscles: extensor digitorum communis muscle, extensor carpi radialis muscle, deltoid muscle, biceps brachii muscle, pronator teres muscle and flexor carpi ulnaris muscle. The Spin Echo T1 sequence in the dorsal plane facilitates assessments of joint surfaces, medial humeral condyle, superficial digital flexor muscle, deep digital flexor muscle, triceps brachii muscle and extensor digitorum lateralis muscle. The Spin Echo T1 sequence in the sagittal plane has a short scan time, but it produces images of lower quality than High Resolution Gradient Echo and XBONE T2 sequences in the sagittal plane.

3D fat-saturated T1 SPACE sequence for the diagnosis of cervical artery dissection

This study aims to demonstrate the added value of a 3D fat-saturated (FS) T1 sampling perfection with application-optimised contrast using different flip angle evolutions (SPACE) sequence compared to 2D FS T1 spin echo (SE) for the diagnosis of cervical artery dissection. Thirty-one patients were prospectively evaluated on a 1.5-T MR system for a clinical suspicion of acute or subacute cervical artery dissection with 3D T1 SPACE sequence. In 23 cases, the axial 2D FS T1 SE sequence was also used; only these cases were subsequently analysed. Two neuroradiologists independently and blindly assessed the 2D and 3D T1 sequences. The presence of recent dissection (defined as a T1 hyperintensity in the vessel wall) and the quality of fat suppression were assessed. The final diagnosis was established in consensus, after reviewing all the imaging and clinical data. Overall sensitivity and specificity were 0.929 and 1 for axial T1 SE, and 0.965 and 0.945 for T1 SPACE (P > 0.05), respectively. The two readers had excellent agreement for both sequences (k = 1 and 0.8175 for T1 SE and T1 SPACE, respectively; P > 0.05). The quality of the fat saturation was similar. Very good fat saturation was obtained in the upper neck. Multiplanar reconstructions were very useful in tortuous regions, such as the atlas loop of the vertebral artery or the carotid petrous entry. 3D T1 SPACE sequence has a shorter acquisition time (3min 25s versus 5min 32s for one T1 SE sequence) and a larger coverage area. 3D T1 SPACE sequence offers similar information with its 2D counterpart, in a shorter acquisition time and larger coverage area.

Combined dynamic contrast-enhancement and serial 3D-subtraction analysis in magnetic resonance imaging of osteoid osteomas

The purpose of this study was to retrospectively correlate the results of dynamic contrast-enhanced magnetic resonance imaging (MRI) with histological and clinical diagnoses in patients with osteoid osteomas. Fifty-four patients with the MR diagnosis of osteoid osteoma were studied. MRI (1.5 Tesla) consisted of thin-section STIR sequences, dynamic 3D T1 gradient echo sequences during application of contrast material, and high-resolution postcontrast T1 spin echo sequences with fat saturation (maximum voxel size 0.6 x 0.6 x 3.0 mm). Evaluation was focused on serial image subtraction during the early phase after contrast injection and on time-intensity curves. The surrounding edema was helpful in finding the nidus in each lesion. In 49 of 54 patients (90.7%), the diagnosis of osteoid osteoma was certain or highly probable (sensitivity 1.0, positive predictive value 0.91). A total of 38 of 54 osteoid osteomas were histologically proven. Five MRI diagnoses were regarded as false positives. A similar proportion has been reported for computed tomography. Tailored high-resolution MR examinations with dynamic contrast enhancement can reliably diagnose osteoid osteomas and exactly localize the nidus without radiation exposure. We propose a stepwise approach with STIR sequences, dynamic contrast-enhanced scanning, and high-resolution postcontrast T1 spin echo sequences with fat saturation.

TMJ disorders and pain: Assessment by contrast-enhanced MRI

Though magnetic resonance (MRI) is a widely accepted standard for the assessment of patients with temporomandibular joint (TMJ) disorders, efforts to correlate symptoms to MRI findings have often given controversial results. Aim of this study was to investigate the correlation between TMJ pain and findings of contrast-enhanced MRI. Thirty-eight consecutive patients with TMJ dysfunction syndrome (study group) were examined with MRI. Protocol included T2 turbo spin-echo sequence, T1 spin-echo sequence, and T2 gradient-echo (acquired with closed jaw, at intermediate and maximal opening). Post-contrast phase was obtained through a fat sat 3D T1 gradient-echo sequence (VIBE). Post-contrast findings in the study group were matched with those obtained in a control group of 33 patients submitted to MRI of the paranasal sinuses. Statistically significant difference was found between condylar medullary bone enhancement in painful TMJ, in painless TMJ and control group. In addition the average thickness of joint soft tissue enhancement in painful TMJ was superior to painless TMJ ( p < 0.0001) and to control group. On multivariate logistic regression analysis, the odds ratio that a painful TMJ showed disk displacement, osteoarthrosis, effusion and JST enhancement were 3.05, 3.18, 1.2 and 11.36, respectively. Though not histologically proven, TMJ enhancement could reflect the presence of inflammation in painful joints. Furthermore, the administration of contrast could be of help for the assessment of patients with orofacial pain, particularly when clinical exploration is insufficient to ascribe the pain to TMJ.

Correlation between semi automated measurement of whole brain atrophy and T2W lesion load with Disability (EDSS) in multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune disease of the central nervous causing severe disability via progressive damage to white matter. Measuring brain paranchymal volume is an objective and reliable surrogate for destructive pathological process in MS. The brain parenchymal fraction (BPF) is the ratio of brain parenchymal volume to the total volume within the surface contour. MATERIALS AND METHODS In this study 20 patients (age 18-53) with definite remittingrelapsing (R-R) or slowly progressive (S-P) MS disease based on MacDonald criteria were selected. [4 slowly progressive (S-P) ,16 Remitting-relapsing (R-R) ].The neurological exam and Expanded Disability Status Score (EDSS) were enrolled by a well qualified neurologist. MR images were obtained on a 1.5 Tesla General Electric SIGNA System. T2 Fast spin echo and T1 Spin Echo sequences, covering the entire brain were gathered in the axial plane 5 mm thickness contiguously with a 256 x 256 acquisition matrix. A multi-step volume analysis was then performed using several processing tools available in semi automated software package including interactive image editing, region of interest pixel counting, registration and threshold. We measured BPF in patients with MS and 34 healthy controls. RESULTS There was strong correlation between EDSS and brain parenchymal atrophy (r=0.67 , p moderate correlation between T2w load and EDSS (r=0.34 p CONCLUSION BPF correlated negatively with expanded disability status scale (EDSS), but not with total T2 hyper intense lesion volume. We conclude that whole-brain atrophy in MS can be reliably and readily quantified by a semi automated approach References Correlation between semi automated measurement of whole brain atrophy and T2W lesion load with Disability (EDSS) in multiple sclerosis 2 of 2 Author Information Elham Rahimian, M.D. Radiologist, Tehran Medical University M. Tahsini, M.Sc. Biomedical Engineer, Sharif Technology University Roya Abolfazli, M.D. Neurologist, Tehran Medical University

Imaging of inflammatory lesions at 3.0 Tesla in patients with clinically isolated syndromes suggestive of multiple sclerosis: a comparison of fluid-attenuated inversion recovery with T2 turbo spin-echo

The aims of this study were to determine and compare the sensitivity of T2 turbo spin-echo (T2 TSE) and fluid-attenuated inversion recovery (FLAIR) sequences at 3.0 T in the detection of inflammatory lesions in patients with clinically isolated syndromes suggestive of multiple sclerosis. Forty-nine patients were examined with a 3.0 T MRI system using 5 mm axial sections of T2 TSE (2:19 min), FLAIR (4:00 min) and pre- and postcontrast T1 spin-echo sequences (3:37 min). Brain lesions were counted and categorized according to their anatomic location. Patients were classified according to Barkhof MRI criteria for FLAIR and T2 TSE sequences. The FLAIR sequence detected more lesions in every anatomic region except for the infratentorial region. The higher sensitivity was significant for the total number of lesions (p<0.01), the juxtacortical (p<0.01), and the periventricular (p=0.01) region. A 9% increase of infratentorial lesions using the T2 TSE sequence was not significant. The higher sensitivity using the FLAIR sequence resulted in one additional MRI criterion in nine patients, whereas the better detection of infratentorial lesions using the T2 TSE sequence resulted in additional MRI criteria in three patients. In conclusion, FLAIR provides the highest sensitivity when compared with the T2 TSE, although T2 TSE still has a diagnostic relevance in terms of MRI criteria classification.

Magnetic resonance imaging in 120 patients with intractable partial seizures: a preoperative assessment

The aim of this study was to describe magnetic resonance imaging (MRI) findings in patients with medically intractable epilepsy and to compare different magnetic resonance (MR) sequences in order to establish a dedicated and shorter scan time imaging protocol of choice. One hundred and twenty patients with seizures that were refractory to medical treatment were assessed by MRI with spin-echo (SE) T1, fast spin-echo (FSE) T2, fluid-attenuated inversion recovery (FLAIR), inversion recovery (IR) and contrast-enhanced T1 SE sequences. Pathological scans were acquired in 78 patients. Hippocampal sclerosis was detected in 30 patients (25%), cerebral, tumoral, mass lesions in 12 patients (10%), vascular malformations in nine patients (7.5%), cortical infarcts in eight patients (6.7%), cerebral infections in four patients (4.2%) and developmental disorders in 15 patients (12.5%). The most common location of the lesions was the temporal lobe (60%). Coronal, thin (slice thickness 4-5 mm) images have proven to be the most useful in the assessment of the hippocampus. FLAIR and IR are particularly useful in the detection of lesions abutting cerebrospinal fluid (CSF) spaces and developmental disorders, respectively, while T1 SE sequences before and after the intravenous administration of gadolinium offer great facility in identifying space-occupying lesions and infections. MRI is the most important diagnostic tool for the assessment of epileptogenic foci, thus playing the primary role in indicating the type of treatment to be applied.

Retromolar trigone tumors: evaluation by magnetic resonance imaging and correlation with pathological data

The aim of this study was to evaluate the diagnostic accuracy of magnetic resonance (MR) images to establish both the T stage and the relationships between the tumors and the surrounding structures in retromolar trigone tumors. Twenty-two patients with squamous cell carcinoma of the retromolar trigone were examined by MR with a superconductive scanner operating at 1.5T. The study was performed with spin-echo (SE) T1 and T2 and short SE T1 sequences (TR 180 ms, TE 15 ms) after the administration of 0.2 mmol/kg of gadolinium-DTPA (Gd-DTPA). The mandible was studied with SE T1weighted sequences and GE sequences. The results were compared with the pathological data on the T stage (TNM classification) and the involvement of the surrounding structures. A positive correlation was found in 19 of the 22 patients with an accuracy of 86%. In one patient, the lesion was classified as T1 by MR which, at surgery, resulted being T4, given the infiltration of the cortical mandible (this infiltration was too limited). In another, the MR showed a T4 lesion because of the presence of low signal intensity in the mandibular marrow with enhancement after the Gd-DTPA injection without cortical erosion, while pathological data revealed a T2 lesion (this signal intensity was secondary to inflammation). In another case, the lesion was classified as T1 by MR which, at surgery, proved to be a T2 lesion. In assessing the involvement of the surrounding structures, MR showed a high accuracy, specificity and sensitivity (>90%). Five false positive cases were observed: in two because of infiltration of the masseter muscle and in the other three, because of infiltration to the pterigoid muscle, mandible and tonsillar bed, respectively, due to the close contact between the tumors and the surrounding structures. Only one false negative case was observed with infiltration of the mandibular marrow. In evaluating the low signal intensity of the mandibular marrow, the accuracy of MR was 87%, the specificity 77% and the sensitivity 100%. In one case, perineural spread along the mandibular nerve was found. In conclusion, MR proved to be highly accurate to study the T stage and examine the relationships between the surrounding structures in cases of retromolar trigone tumors.

Magnetic resonance tomography of focal hepatic lesions using the para-magnetic contrast medium, gadolinium DTPA. First clinical results

The use of the para-magnetic contrast medium gadolinium DTPA for magnetic resonance tomography of focal lesions in the liver was investigated in 31 patients. Two dosage schedules of the contrast medium (0.1 and 0.2 mmol/kg body weight were used with field strengths of 0.35 and 0.5 Tesla. Using T1 sequences, gadolinium DTPA showed increased signal intensity in the liver and in tumours, but this was significantly more marked in the tumour. On T1 spin-echo sequences, previously iso-intense lesions became visible after administration of contrast. On the other hand, contrast-enhanced lesions were less well seen on inversion recovery sequences because of a reduction in the contrast between tumour and liver tissue. The contrast between tumour and liver tissue was not improved by gadolinium DTPA in comparison with precontrast inversion recovery sequences and T2 spin-echo sequences. The perfusion of intra-hepatic tumours could be elucidated by magnetic resonance tomography after the administration of gadolinium DTPA.