Proton Density-weighted Sequences Research Articles

Improve definition of titanium tandems in MR-guided high dose rate brachytherapy for cervical cancer using proton density weighted MRI

BackgroundFor cervical cancer patients treated with MR-guided high dose rate brachytherapy, the accuracy of radiation delivery depends on accurate localization of both tumors and the applicator, e.g. tandem and ovoid. Standard T2-weighted (T2W) MRI has good tumor-tissue contrast. However, it suffers from poor uterus-tandem contrast, which makes the tandem delineation very challenging. In this study, we evaluated the possibility of using proton density weighted (PDW) MRI to improve the definition of titanium tandems.MethodsBoth T2W and PDW MRI images were obtained from each cervical cancer patient. Imaging parameters were kept the same between the T2W and PDW sequences for each patient except the echo time (90 ms for T2W and 5.5 ms for PDW) and the slice thickness (0.5 cm for T2W and 0.25 cm for PDW). Uterus-tandem contrast was calculated by the equation C = (Su-St)/Su, where Su and St represented the average signal in the uterus and the tandem, respectively. The diameter of the tandem was measured 1.5 cm away from the tip of the tandem. The tandem was segmented by the histogram thresholding technique.ResultsPDW MRI could significantly improve the uterus-tandem contrast compared to T2W MRI (0.42±0.24 for T2W MRI, 0.77±0.14 for PDW MRI, p=0.0002). The average difference between the measured and physical diameters of the tandem was reduced from 0.20±0.15 cm by using T2W MRI to 0.10±0.11 cm by using PDW MRI (p=0.0003). The tandem segmented from the PDW image looked more uniform and complete compared to that from the T2W image.ConclusionsCompared to the standard T2W MRI, PDW MRI has better uterus-tandem contrast. The information provided by PDW MRI is complementary to those provided by T2W MRI. Therefore, we recommend adding PDW MRI to the simulation protocol to assist tandem delineation process for cervical cancer patients.

Adherence to MRI protocol consensus guidelines in multiple sclerosis: An Australian multi‐centre study

Multiple sclerosis (MS) is a debilitating disease that causes significant morbidity within a young demographic. Diagnostic guidelines for MS have evolved, and imaging has played an increasingly important role in diagnosis over the last two decades. For imaging to contribute to diagnosis in a meaningful way, it must be reproducible. Consensus guidelines for MRI in MS exist to define correct sequence type and imaging technique, but it is not clear to what extent they are followed. This study reviewed MRI studies performed on Australian individuals presenting with a first clinical diagnosis of central nervous system demyelination (FCD) for adherence to published guidelines and discussed practical implementation of MS guidelines in light of recent updates. The Ausimmune study was a prospective case control study of Australian participants presenting with FCD from 2003 to 2006. Baseline cranial and spinal cord MRI studies of 226 case participants from four separate Australian regions were reviewed. MRI sequences were classified according to anatomical location, slice plane, tissue weighting and use of gadolinium-containing contrast media. Results were compared with the 2003 Consortium of Multiple Sclerosis Centres MRI protocol for the diagnosis of MS. The composition of core cranial MRI sequences performed varied across the 226 scans. Of the studies, 91% included sagittal fluid attenuated inversion recovery (FLAIR) sequences. Cranial axial T2-weighted, axial FLAIR and axial proton density-weighted sequences were performed in 88%, 60% and 16% (respectively) of scans. Only 25% of the studies included a T1-weighted contrast-enhanced sequence. Concordance with the guidelines in all sequences was very low (2). Only a small number of MRI investigations performed included all of the sequences stipulated by consensus guidelines. This is likely due to poor awareness in the imaging community of the guidelines and the rationale behind certain sequences. Radiologists with a sub-speciality interest in neuroradiology should take ownership of this issue and ensure that recommended imaging guidelines are followed.

The anterior shear and distraction tests for craniocervical instability. An evaluation using magnetic resonance imaging

Screening for integrity of the ligaments of the craniocervical complex has been suggested prior to the application of manual techniques to the upper cervical spine. However, most tests proposed lack validation limiting their usefulness clinically. This study examined the effect of the anterior shear test for the transverse ligament and the distraction test for the tectorial membrane in normal volunteers. MRI was performed in supine in neutral and end-range stress test positions in 16 individuals using proton density-weighted sequences and a standard head coil in a 3-T system. Measurements were made with respect to a strictly standardised protocol. The anterior shear test was assessed using changes in atlantodental interval and distance from the anterior arch of the atlas to the posterior aspect of the odontoid process. Distraction testing for the tectorial membrane was assessed by changes in basion-dental interval and by direct measurement of the tectorial membrane. Differences were compared using Wilcoxon Sign Rank tests or paired t-test depending upon each variables assessment of normality. Anterior shear testing resulted in a 0.41 mm mean increase in atlantodental interval (p = 0.03) and 0.35 mm mean increase in axial plane distance (p = 0.05). Distraction testing for the tectorial membrane resulted in a 0.64 mm increase in basion-dental interval (p < 0.01) and a 1.11 mm increase in direct ligament length measurement (p = 0.02). Reliability of measurements ranged from moderate to substantial. These results indicate that these tests produce a consistent direct effect on the transverse ligament and the tectorial membrane which is consistent with their theorised mechanism for clinical use.

An anatomical study of normal meniscal roots with isotropic 3D MRI at 3T

To clarify the morphological features of normal meniscal roots on magnetic resonance (MR) imaging with an isotropic 3D proton density-weighted (PDW) sequence. 3D PDW MR was performed in sixty-two patients at 3T before knee arthroscopy. MR images of 34 normal medial menisci and 33 intact lateral menisci confirmed by arthroscopy were retrospectively evaluated. MR signals, insertion sites, dimensions and courses of four meniscal roots were recorded. The anterior root of medial meniscus (ARMM) was typically hypointense, while the posterior root of medial meniscus (PRMM) and the anterior root of lateral meniscus (ARLM) were prone to be hyperintense or showing a comblike signal, and the posterior root of lateral meniscus (PRLM) was usually hypointense or comblike on PDW MR images. ARMM and PRLM had more complex and diverse insertion patterns than ARLM and PRMM. There were significant statistical differences of the lengths, widths, heights and course angles among four meniscal roots (all P<0.001). The signal intensity of each meniscal root can be hypointense, hyperintense, or comblike on 3D PDW MR images. ARMM and PRLM have more complex and diverse insertion patterns than ARLM and PRMM. The dimensions and courses of four meniscal roots all differ.

Construct Validity of Clinical Tests for Alar Ligament Integrity: An Evaluation Using Magnetic Resonance Imaging

The alar ligaments are integral to limiting occipito-atlanto-axial rotation and lateral flexion and enhancing craniocervical stability. Clinical testing of these ligaments is advocated prior to the application of some cervical spine manual therapy procedures. Given the absence of validation of these tests and the potential consequences if manipulation is applied to an unstable upper cervical spine segment, exploration of these tests is necessary. The purpose of this study was to examine the direct effect of the side-bending and rotation stress tests on alar ligaments using magnetic resonance imaging (MRI). This was a within-participant experimental study. Sixteen participants underwent MRI in neutral and end-range stress test positions using proton density-weighted sequences in a 3-Tesla system. Measurements followed a standardized protocol relative to the position of the axis. Distances were measured from dens tip to the inferior margin of the foramen magnum and from midsubstance of the dental attachment of the ligament to its occipital insertion. Between-side differences were calculated for each measurement to account for inherent asymmetries in morphology. Differences were compared between the test and neutral positions using a Wilcoxon signed rank test. Side-bending stress tests produced a median between-side difference in ligament length of +1.15 mm. Rotation stress tests produced a median between-side difference in ligament length of +2.08 mm. Both results indicate increased measurement of the contralateral alar ligament. Limitations Assessment could be made only in the neutral position due to imaging limitations. Clinical texts state that tests should be performed in 3 positions: neutral, flexion, and extension. Both side-bending and rotation stress testing result in a measurable increase in length of the contralateral alar ligament. This finding is consistent with mechanisms that have been described to support their use in clinical practice.

Lesiones del cartílago articular de la rodilla mediante resonancia magnética: ventajas del uso de secuencias ponderadas en densidad protónica en 3.0 Teslas

The aim of this article is to demonstrate a method for studying knee joint cartilage to be used in a 3.0 Tesla (3.0 T) MRI device. The use of proton density-weighted sequences, with and without fat suppression, and the precise setting of the image parameters to the requisites of 3.0 T, give very high resolution images with an optimum contrast between structures, so that the elements of interest can be observed with greater accuracy. A more powerful magnetic field influences the setting of the image parameters and provides useful advantages.

Magnetic resonance histologic correlation in rotator cuff tendons

To relate histologic changes in rotator cuff tendons to the appearance on T1-weighted as well as fat-suppressed T2-weighted and proton density-weighted magnetic resonance imaging (MRI) sequences. T1-weighted, fat-suppressed T2-weighted and fat-suppressed proton density-weighted sequences of 18 cadaveric shoulders were acquired. The supraspinatus, infraspinatus, and subscapularis tendons were evaluated histologically. Twenty-six abnormalities were found in 23 of 37 tendons. In addition, histologically normal tendon parts (n = 32), including three segments with normal histology but abnormal MR signal, considered to represent magic angle effects, were defined. All regions of interest (ROIs) were evaluated by two musculoskeletal radiologists independently and blinded to histology. In the 26 areas with anatomically intact tendons but abnormal histological findings mucoid degeneration (n = 13), chondroid metaplasia (n = 11), fatty infiltration (n = 1), and foreign-body granuloma (n = 1) after tendon suture were found. Compared to normal tendon, mucoid degeneration was hyperintense on T2-weighted fat-suppressed (P = 0.007) and on proton density-weighted fat-suppressed images (P = 0.006). Chondroid metaplasia was hyperintense compared to normal tendon in all sequences (P < 0.05). Mucoid degeneration was hypointense compared to chondroid metaplasia on T2-weighted fat-suppressed images (P = 0.038) and hypointense compared to magic angle artifacts on T1-weighted images (P = 0.046). Chondroid metaplasia of rotator cuff tendons appears to be more common than expected. Both mucoid degeneration and chondroid metaplasia may explain increased tendon signal on MR images of the rotator cuff.

Effect of butylscopolamine on image quality in MRI of the prostate

To evaluate the impact of butylscopolamine on the quality of magnetic resonance imaging (MRI) images of the prostate. Eighty-two MRI examinations of the prostate were retrospectively analysed. MRI was performed with a combined endorectal/body phased-array coil including proton density-weighted (PD) sequence, T1-weighted turbo spin-echo (TSE)-sequence, and T2-weighted TSE-sequences. Forty milligrams of butylscopolamine was administered intramuscularly in 31 patients (im-group) and intravenously in 30 patients (iv-group). Twenty-one patients did not receive premedication with butylscopolamine (ø-group). Overall image quality, delineation of the bowel wall, and visualization of the prostate, neurovascular bundle, and pelvic lymph nodes were evaluated qualitatively using a five-point scale (from 1=excellent to 5=non-diagnostic/structure not discernible). Motion artefacts within the endorectal coil were quantified by baseline adjusted signal intensities inside the endorectal coil area. Delineation of the bowel wall using the PD-sequence was significantly improved after both intramuscular and intravenous butylscopolamine administration (ø-group: 3.6+/-0.7; im-group: 2.9+/-0.7; iv-group: 2.9+/-0.7; p=0.001). However, there were no significant differences in motion artefacts measured within the endorectal coil (ø-group: 1.18+/-0.14; im-group: 1.15+/-0.11; iv-group: 1.12+/-0.06; p=0.39). There were also no significant differences in qualitative assessment of visualization of the prostate, neurovascular bundle, pelvic lymph nodes, and of overall image quality between the study groups. : In conclusion, butylscopolamine had only a small effect on image quality and is not mandatory for MRI of the prostate.

Prevalence of Compositional Features in Subclinical Carotid Atherosclerosis Determined by High-Resolution Magnetic Resonance Imaging in Chinese Patients With Coronary Artery Disease

Previous studies have reported that carotid atherosclerosis frequently can be seen in coronary artery disease (CAD) patients. This study sought to determine the prevalence of compositional features in subclinical carotid atherosclerosis by MRI in CAD patients. Ninety-six subjects with suspected CAD but free of neurological symptoms underwent coronary CT angiography and carotid MRI including 3-dimensional time-of-flight, T1-weighted, T2-weighted, and proton density-weighted sequences at 3 T within a 2-week interval. The coronary artery calcium score (CACS) and degree of stenosis were measured. Areas for carotid lumen, wall, total vessel, and percent wall volume (wall volume/total vessel volume) were measured. The prevalence of carotid calcification, lipid-rich necrotic core, intraplaque hemorrhage, and surface disruption in coronary stenosis and CACS categories were determined. Carotid percent wall volume was correlated with CACS (P=0.001). Both coronary stenosis and CACS were significantly associated with presence of carotid calcification (OR=5.79 for 1%-49% vs 0% stenosis; OR=10.23 for >50% vs 0% stenosis; OR=10.65 for CACS 1-399 vs CACS 0; and OR=20.28 for CACS >400 vs CACS 0; all P<0.05) and lipid-rich necrotic core (OR=10.29 for 1%-49% vs 0% stenosis; OR=4.66 for >50% vs 0% stenosis; OR=8.23 for CACS 1-399 vs CACS 0; and OR=11.87 for CACS >400 vs CACS 0; all P<0.05) High prevalence of lipid-rich necrotic core was found in low-grade coronary stenosis (75.6% in 1%-49% stenosis) and CACS (73.5% in CACS 1-399). Carotid plaque burden and compositional features are significantly associated with CAD severity. The finding of high prevalence of lipid-rich necrotic core in patients with low-grade coronary stenosis and CACS suggests the need for early monitoring of carotid atherosclerosis in CAD patients.

MRI morphometry, cartilage damage and impaired function in the follow-up after slipped capital femoral epiphysis

To assess rotation deficits, asphericity of the femoral head and localisation of cartilage damage in the follow-up after slipped capital femoral epiphysis (SCFE). Magnetic resonance imaging studies were obtained in adult patients with a history of SCFE. A total of 35 hips after SCFE in 26 patients (mean age 24.1 +/- 6.5, mean follow-up 11.9 +/- 6.1 years) were evaluated. The control group comprised 20 healthy hips from 10 young adults with an average age of 23.9 +/- 3.7 years. The MR protocol included a T1-weighted sequence with a 3D volumetric interpolated breath-hold sequence and a radial 2D proton density-weighted sequence around the femoral neck. Images were evaluated for alpha angle and cartilage damage in five positions around the femoral head. Hip function was evaluated at the time of MRI and correlated with MRI results. Mann-Whitney U test and Spearman's correlation coefficient were used for statistical analysis. In the hips after SCFE alpha angles were significantly increased in the anterosuperior (74.1 degrees +/- 18.8 degrees ) and superior (72.5 degrees +/- 21.5 degrees ) positions and decreased in the posterior position (25.0 degrees +/- 7.2 degrees ). Cartilage damage was dominant in the anterosuperior and superior positions. Impaired rotation significantly correlated with increased anterosuperior, superior and posterosuperior alpha angles. The data support an anterosuperior and superior cam-type deformity of the femoral head-neck junction in the follow-up after SCFE. MRI after SCFE can be used to assess anterosuperior and superior alpha angles, since the anterior alpha angle by itself may underestimate asphericity and is not associated with rotation deficits.

Lipoma Arborescens of Subacromial-subdeltoid Bursa: Ultrasonographic Findings

The present study describes the ultrasound findings of lipoma arborescens arising in the subacromial-subdeltoid bursa. Ultrasound examinations were performed in seven shoulder joints of six patients with shoulder pain and functional limitations, as well as suspected rotator cuff abnormalities. Magnetic resonance imaging (MRI) was also performed in all cases. T1-weighted spin-echo and T2-weighted turbo spin-echo images, and a proton density-weighted sequence with fat spectral suppression or a short inversion time inversion recovery were obtained in a 1.5-T unit. Synovial-based hyperechoic villous proliferations and a diffuse synovial thickening associated with a sonolucent effusion in the subacromial-subdeltoid bursa were seen in all cases. Color Doppler showed no vascularisation in any of the cases. The fatty nature of the synovial hyperechoic proliferations was confirmed by MRI in all cases. In conclusion, ultrasonographic findings of lipoma arborescens arising in the subacromial-subdeltoid bursa suggest villous hyperechoic synovial proliferations associated with an effusion. Confirmation of the fatty nature of the synovial proliferation should be performed with MRI, which allows an unequivocal diagnosis.

Accessory Head of Biceps Brachii Muscle: Anatomy, Histology, and MRI in Cadavers

The purpose of our study is to describe and define an anatomic variation located close to the bicipital groove using MRI with gross anatomic and histologic correlation in cadavers. Ten fresh male human shoulders were harvested and used in this investigation. They were derived from persons with a mean age of death of 78.9 years (age range, 58-92 years). MR arthrography using proton density-weighted sequences was used to obtain images in axial, coronal, and sagittal planes. After imaging, the specimens were cut in axial, coronal, and sagittal sections using a band saw. The slices were then photographed to allow correlation with the MR arthrographic images, followed by histologic analysis. Two anomalous tendons, both intimate with the tendon of the long head of the biceps brachii muscle in the bicipital groove, were recognized. The origin of both tendons was in the greater tuberosity near the articular capsule. These structures had a muscular belly that was joined with the other biceps bellies. At the level of the bicipital groove, the anomalous tendons appeared as hypointense structures in proton density-weighted images, with a mostly flat morphology in axial and coronal planes. The average dimensions of these structures were 45.5 (craniocaudal)x6.2 (anteroposterior)x0.85 (mediolateral) mm. The MR images, gross anatomic inspection, and histologic information led us to conclude that these anomalous structures were accessory heads of the biceps brachii muscle.

Chiasma crurale: intersection of the tibialis posterior and flexor digitorum longus tendons above the ankle. Magnetic resonance imaging–anatomic correlation in cadavers

PurposeTo determine the precise anatomy and magnetic resonance (MR) imaging appearance of the chiasma crurale in cadavers, paying special attention to degenerative changesMaterial and methodsTwelve fresh human ankles were harvested from 11 nonembalmed cadavers (mean age at death 77 years) and used according to institutional guidelines. MR imaging and MR tenography were used to investigate the anatomy of the chiasma crurale using proton density-weighted sequences. The gross anatomy of the chiasma crurale was evaluated and compared to the MR imaging findings. Histology was used to elucidate further the structure of the chiasma crurale.ResultsAbove the chiasma, five specimens had a small amount of fat tissue between the tibialis posterior and flexor digitorum longus tendon. In all specimens both tendons had a sheath below the chiasma but not above it. At the central portion of the chiasma there was no soft tissue between the tendons, except in two specimens that showed an anatomic variant consisting of a thick septum connecting the tibial periosteum and the deep transverse fascia of the leg. In MR images, eight specimens showed what were believed to be degenerative changes in the tendons at the level of the chiasma. However, during gross inspection and histologic analysis of the specimens, there was no tendon degeneration visible.ConclusionAt the central portion of the chiasma, there is no tissue between the tibialis posterior and flexor digitorum longus tendons unless there is an anatomic variant. At the chiasma crurale, areas with irregular tendon surfaces are normal findings and are not associated with tendon degeneration (fraying).

Comparative study of the lower uterine segment after Cesarean section using ultrasound and magnetic resonance tomography

To determine whether ultrasound (US) or magnetic resonance imaging (MRI) gave more accurate and objective information about the thickness and continuity of scarred isthmical myometrium following previous Caesarean section (CS), US and MRI assessments of the scarred myometrium in 10 pregnant women (37-41 weeks gestation) after 1-8 CS were compared with each other and with findings at subsequent elective CS. Vaginal ultrasound gave more accurate information about the condition of the scarred isthmical myometrium than MRI, since US always allowed precise differentiation of isthmical myometrium from the urinary bladder wall and thus measurements of the scar thickness; there was a good correlation to intraoperative observations. MRI achieved better contrast resolution with T2- than T1-weighted and proton density-weighted spin-echo sequences. However, differentiation of the various tissues was either impossible (T1- and protondensity-weighted sequences) or less informative than with US. Image quality of body and posterior wall of the uterus was better with MRI (T2-weighted sequence) than with US.

3.0 vs 1.5 T MRI in the detection of focal cartilage pathology – ROC analysis in an experimental model

To use receiver operator characteristics (ROC) analysis for assessing the diagnostic performance of three cartilage-specific MR sequences at 1.5 and 3 T in detecting cartilage lesions created in porcine knees. Eighty-four cartilage lesions were created in 27 porcine knee specimens at the patella, the medial and lateral femoral and the medial and lateral tibial cartilage. MR imaging was performed using a fat saturated spoiled gradient echo (SPGR) sequence (in plane spatial resolution/slice thickness: 0.20 x 0.39 mm2/1.5 mm) and two fat saturated proton density weighted (PDw) sequences (low spatial resolution: 0.31 x 0.47 mm2/3 mm and high spatial resolution: 0.20 x 0.26 mm2/2 mm). The images were independently analyzed by three radiologists concerning the absence or presence of lesions using a five-level confidence scale. Significances of the differences for the individual sequences were calculated based on comparisons of areas under ROC curves (A(Z)). The highest A(Z)-values for all three radiologists were consistently obtained for the SPGR (A(Z) = 0.84) and the high-resolution (hr) PDw (A(Z) = 0.79) sequences at 3T. The corresponding A(Z)-values at 1.5 T were 0.77 and 0.69; the differences between 1.5 and 3 T were statistically significant (P < 0.05). A(Z)-values for the low-resolution PDw sequence were lower: 0.59 at 3 T and 0.55 at 1.5 T and the differences between 1.5 and 3T were not significant. With optimized hr MR sequences diagnostic performance in detecting cartilage lesions was improved at 3 T. For a standard, lower spatial resolution PDw sequence no significant differences, however, were found.

Osteochondritis dissecans of the temporomandibular joint

A case is reported of a 43-year-old female patient presenting bilateral osteochondritis dissecans (OCD) of the temporomandibular joint (TMJ), in different stages for each side, associated with avascular necrosis (AVN) of the right condyle. Additionally observed was anterior disk displacement without reduction for both sides. We have proposed an adaptation of the previous classification of OCD for cases affecting the TMJ. We have also stressed the fundamental role of panoramic radiography on the diagnosis of stage 3 and stage 4 OCD of the TMJ. In relation to MRI, we have recommended sagittal (slice thickness of 2 mm) and coronal (slice thickness of 1 mm) fast spin-echo proton density-weighted sequences to better identify bone lesions (stage 1 and 2) and also localize osteochondral loose bodies; and coronal (slice thickness of 1 mm) fat-suppressed fast spin-echo T2 weighted sequence to better evaluate OCD (stable or unstable) and the features of the occasionally associated AVN (acute or chronic).

Assessment and correction of B1‐induced errors in magnetization transfer ratio measurements

The magnetization transfer ratio (MTR) is strongly related to the field strength (B(1)) of the saturation pulse. B(1) variations therefore can result in significant MTR variations and can affect histogram analysis, particularly if data from a large volume of interest are included. A multicenter study was performed to determine the typical range of B(1) errors and the corresponding MTR variations in brain tissue of healthy volunteers. Seven subjects were included at each center resulting in a total cohort of 28 subjects. Additionally, numerical simulations were done to study this relationship more generally for pulsed saturation. It could be demonstrated, both theoretically and empirically, that for typical B(1) errors there is a linear relationship between B(1) error and the corresponding MTR change. In addition, for proton density-weighted sequences, this relationship seems to be largely independent of the underlying relaxation properties. Mean B(1) errors in the entire brain were typically in the range between -3% and -7%. Due to different coil characteristics, significant MTR differences between different scanners and sites were observed. Using a simple correction scheme that is based on a linear regression analysis between MTR and B(1) data it was possible to reduce the intersubject variation by approximately 50%. Furthermore, interscanner variation could be reduced such that no significant differences between scanners could be detected. The correction scheme may be useful when investigating MTR as an outcome measure in single or multicenter studies.

Comparison of MRI graded cartilage and MRI based volume measurement in knee osteoarthritis.

The aim of this study was to investigate the relationship between the femoral, tibial and patellar cartilage volume and MRI grading of the articular cartilage in patients with knee OA. Articular cartilage volumes of 65 postmenopausal women were determined by processing images acquired in the sagittal plane using a fast spin echo proton density-weighted sequence. The articular cartilages were divided into 5 compartments including lateral and medial tibial, lateral and medial femoral and patellar compartments. The articular cartilages were graded using a modified Outerbridge classification. Grade 0 indicated intact cartilage, grade 1 chondral softening with normal contour, grade 2 superficial fraying, grade 3 surface irregularity and thinning and grade 4 full thickness cartilage loss. The grades of articular cartilage were compared with cartilage volume measurements. In medial femoral cartilage, grade 1 had more volume compared to grade 0 cartilage (p: 0.017). In medial tibial cartilage, grade 1 had more volume compared to grade 0 and grade 2 cartilage (p: 0.045 and p: 0.027, respectively). In patellar cartilage, grade 1 cartilage had significantly more volume than grade 0 cartilage (p: 0.007). In lateral tibial and femoral cartilages, no significant difference was observed between grade 0 and grade 1 cartilage. Cartilage volume correlates well with MR grading of articular cartilage. The higher the grade of the cartilage the less the volume, with the exception of grade 1 lesions. Grade 1, reflects oedema in the cartilage and has a conflicting effect on volume measurement. The combination of MRI based volume measurement and grading of articular cartilage may provide an accurate method for the non-invasive evaluation and follow-up of articular cartilage.

Comparison of MRI graded cartilage and MRI based volume measurement in knee osteoarthritis.

The aim of this study was to investigate the relationship between the femoral, tibial and patellar cartilage volume and MRI grading of the articular cartilage in patients with knee OA. Articular cartilage volumes of 65 postmenopausal women were determined by processing images acquired in the sagittal plane using a fast spin echo proton density-weighted sequence. The articular cartilages were divided into 5 compartments including lateral and medial tibial, lateral and medial femoral and patellar compartments. The articular cartilages were graded using a modified Outerbridge classification. Grade 0 indicated intact cartilage, grade 1 chondral softening with normal contour, grade 2 superficial fraying, grade 3 surface irregularity and thinning and grade 4 full thickness cartilage loss. The grades of articular cartilage were compared with cartilage volume measurements. In medial femoral cartilage, grade 1 had more volume compared to grade 0 cartilage (p: 0.017). In medial tibial cartilage, grade 1 had more volume compared to grade 0 and grade 2 cartilage (p: 0.045 and p: 0.027, respectively). In patellar cartilage, grade 1 cartilage had significantly more volume than grade 0 cartilage (p: 0.007). In lateral tibial and femoral cartilages, no significant difference was observed between grade 0 and grade 1 cartilage. Cartilage volume correlates well with MR grading of articular cartilage. The higher the grade of the cartilage the less the volume, with the exception of grade 1 lesions. Grade 1, reflects oedema in the cartilage and has a conflicting effect on volume measurement. The combination of MRI based volume measurement and grading of articular cartilage may provide an accurate method for the non-invasive evaluation and follow-up of articular cartilage.

Fast Fluid-Attenuated Inversion-Recovery MR of Intracranial Infections

PURPOSE To assess the usefulness of fast fluid-attenuated inversion-recovery (FLAIR) MR sequences in the diagnosis of intracranial infectious diseases. METHODS We compared fast FLAIR images with conventional spin-echo images (T1- and T2-weighted) obtained in 20 patients with infectious diseases (six with encephalitis, five with brain abscesses, three with meningitis, two with meningoencephalitis, two with Creutzfeldt-Jakob disease, one with epidural empyema, and one with cysticercosis). Two neuroradiologists independently reviewed the FLAIR images and compared them with the conventional spin-echo images, obtaining agreement in all patients. RESULTS FLAIR images of diagnostic quality were obtained in 18 patients. In two patients, FLAIR images were degraded by motion. Lesions in the patients with encephalitis and meningoencephalitis were better delineated on FLAIR images than on spin-echo images. FLAIR images clearly depicted lesions in the basal ganglia in both patients with Creutzfeldt-Jakob disease. In patients with brain abscess, meningitis, cysticercosis, and epidural empyema, FLAIR images provided no more information than conventional spin-echo images, and the lesions were seen better on postcontrast T1-weighted spin-echo images. CONCLUSION Fast FLAIR images showed pathologic changes in intracranial infectious diseases better than or as well as conventional T2- and proton density-weighted spin-echo sequences. However, postcontrast T1-weighted spin-echo sequences resulted in better visibility of abscess, meningitis, cysticercosis, and epidural empyema than did FLAIR images.