Imaging of Metabolic Bone Diseases: The Spine View, Part I.

Metabolic bone diseases comprise a wide spectrum. Of them, osteoporosis is the most frequent and the most commonly found in the spine, with a high impact on health care systems and on morbidity due to vertebral fractures (VFs).This article discusses state-of-the-art techniques on the imaging of metabolic bone diseases in the spine, from the well-established methods to the latest improvements, recent developments, and future perspectives.We review the classical features of involvement of metabolic conditions involving the spine. Then we analyze the different imaging techniques for the diagnosis, characterization, and monitoring of metabolic bone disease: dual-energy X-ray absorptiometry (DXA) and DXA-based fracture risk assessment applications or indexes, such as the geometric parameters, Bone Strain Index, and Trabecular Bone Score; quantitative computed tomography; and magnetic resonance and ultrasonography-based techniques, such as radiofrequency echographic multi spectrometry. We also describe the current possibilities of imaging to guide the treatment of VFs secondary to metabolic bone disease.

Imaging of Metabolic Bone Diseases: The Spine View, Part II.

Metabolic bone diseases comprise a wide spectrum. Osteoporosis, the most frequent, characteristically involves the spine, with a high impact on health care systems and on the morbidity of patients due to the occurrence of vertebral fractures (VFs).Part II of this review completes an overview of state-of-the-art techniques on the imaging of metabolic bone diseases of the spine, focusing on specific populations and future perspectives. We address the relevance of diagnosis and current status on VF assessment and quantification. We also analyze the diagnostic techniques in the pediatric population and then review the assessment of body composition around the spine and its potential application. We conclude with a discussion of the future of osteoporosis screening, through opportunistic diagnosis and the application of artificial intelligence.

Improved detection of subchondral erosions in the sacroiliac joints with T1-weighted fat-suppressed MRI.

OBJECTIVE: To compare the diagnostic performance of two different sets of magnetic resonance imaging (MRI) for the detection of subchondral erosions in the sacroiliac joints regarding the application of fat-water separation techniques when acquiring T1-weighted (T1w) images, using multi-detector computed tomography (MDCT) as the reference standard. METHODS: We retrospectively included 31 consecutive patients having or being suspected for axial spondyloarthritis (SpA) assessed using both MRI and MDCT. Three sets of images were independently assessed for the presence of erosions by two musculoskeletal radiologists (R1, R2): (1) MRI with standard T1w without fat suppression, (2) MRI with both T1w with and without fat suppression, and (3) MDCT. The diagnostic performance of both sets of MRIs was assessed using MDCT as the referent. RESULTS: The assessment of T1w images with fat suppression substantially increased sensitivity (76% vs. 63% R1; 70% vs. 60% R2), specificity (97% vs. 84% R1; 96% vs. 81% R2), positive predictive value (85% vs. 45% R1; 81% vs. 40% R2), and overall accuracy (94% vs. 80% R1; 92% vs. 77% R2) in the detection of erosions when compared to the assessment using T1w images without fat suppression. CONCLUSION: The assessment of T1w images with fat suppression substantially improves the diagnostic performance of MRI in the detection of erosions in the sacroiliac joints. KEY POINTS: • The presence of erosions in the sacroiliac joints may influence the decision on the diagnosis of axial spondyloarthritis. • T1w fat-suppressed MR imaging relatively increases the contrast between the joint space (high signal) and the adjacent subchondral bone (low signal), potentially improving the detection of erosions in the sacroiliac joints. • T1w fat-suppressed images improve the diagnostic performance of MRI in the detection of erosions in the sacroiliac joints compared to T1w without fat suppression, using MDCT as the reference.

MDCT arthrography assessment of scaphoid nonunion advanced collapse: distribution of cartilage damage and relationship with scaphoid nonunion features.

OBJECTIVES: Our primary aim was to evaluate the distribution and severity of cartilage damage in a sample of patients with scaphoid nonunion advanced collapse (SNAC), assessed on MDCT arthrography, with regard to two well-known SNAC staging systems. Secondarily, we wanted to see if the degree of cartilage damage varied with the location of the nonunion. METHODS: We retrospectively included 35 patients with a history of SNAC who had undergone MDCT arthrography. The location of the fracture was defined as the proximal, middle, or distal third of the scaphoid. Cartilage damage was assessed in 14 distinct regions of the wrist using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) system. Staging of SNAC for each patient was based on the distribution of cartilage damage seen on MDCT arthrography. The one-way ANOVA test was used to evaluate whether global cartilage damage scores differed between patients with proximal vs middle and distal nonunion. RESULTS: The radial styloid-scaphoid (85.7%), the scaphoid-trapezium-trapezoid (60%), the scapho-capitate (57.1%), and the proximal radio-scaphoid joints (42.9%) were most commonly affected by degenerative cartilage damage. A substantial number of patients could not be classified according to the two SNAC staging systems. Patients with proximal nonunion exhibited a higher mean score of global cartilage damage than patients with middle or distal nonunion: 14.3 ± 9.5 (95% CI 9.8, 18.7) vs 8.6 ± 6.9 (95% CI 4.7, 12.4); p < 0.0001. CONCLUSION: The distribution of cartilage damage does not always follow the pattern of progressive osteoarthritis widely described in SNAC. Proximal scaphoid nonunion is related to greater severity of global cartilage damage.

CT Features of Vertebral Venous Congestion Simulating Sclerotic Metastases in Nine Patients With Thrombosis of the Superior Vena Cava.

OBJECTIVE: The purpose of this retrospective study is to describe the CT features of vertebral venous congestion simulating sclerotic metastases in nine patients with thrombosis of the superior vena cava. MATERIALS AND METHODS: We analyzed all cases of obstruction of the superior vena cava recorded in our radiologic teaching files since 2006, to identify cases with vertebral venous congestion simulating sclerotic metastases. The following CT features were analyzed: the underlying cause, exact level, and length of the venous obstruction; the pattern of collateral venous pathways visualized as enlarged and densely opacified vascular channels; and the characteristics of the vertebral venous congestion. RESULTS: Nine patients referred for CT examinations between 2006 and 2014 were included in the present study. The pathways that underwent contrast enhancement included the anterior or lateral thoracic pathways in eight patients, the mediastinal pathways in seven patients, and the azygos and vertebral pathways in nine patients. Vertebral venous congestion was observed in 30 vertebrae and was specifically noted in the vertebral body (n = 25), pedicle (n = 11), lamina (n = 3), and spinous process (n = 1). The density of vertebral bone enhancement ranged from 413 to 1480 HU. The limits were well defined in eight lesions and ill defined in 22 lesions. In 23 lesions, a vessel was noted within the vertebrae, in close contact with the vertebrae, or in both locations. CONCLUSION: Development of a vertebral venous collateral system can lead to vertebral venous congestion, resulting in focal and patchy enhancement of the vertebrae, which can be mistaken for sclerotic metastases.

Metabolic Bone Disease in Patients with Malabsorption.

Chronic inflammation and malabsorption in gastrointestinal disease can cause bone metabolism alterations and bone mineral loss in children and adults. Gastrointestinal disease is often forgotten as a cause of osteoporosis, osteopenia, or osteomalacia. The etiology of pathologic bone alterations in gastrointestinal disease is multifactorial. Bone alterations were thought to result simply from intestinal malabsorption, but a more complex interaction between cytokines and local/systemic factors influencing bone formation and resorption is envisaged. This review provides an updated discussion on bone alterations in patients with malabsorption due to celiac disease or inflammatory bowel disease.

Trabecular structure analysis using C-arm CT: comparison with MDCT and flat-panel volume CT.

PURPOSE: This paper assesses interscan, interreader, and intrareader variability of C-arm CT and compares it to that of flat-panel volume-CT (fpVCT) and high-definition multi-detector-CT (HD-MDCT). METHODS: Five cadaver knee specimens were imaged using C-arm-CT, fpVCT, and HD-MDCT. Apparent (app.) trabecular bone volume fraction (BV/TV), app. trabecular number (TbN), app. trabecular spacing (TbSp), and app. trabecular thickness (TbTh) of the proximal tibia were measured by three readers. Interreader, intrareader, and interscan variability for C-arm CT was expressed as coefficient of variation (CV), standard deviation (SD), and intraclass correlation coefficient (ICC). RESULTS: With the exception of app.TbSp (CV: 7.05-9.35%, SD: 0.06-0.09, ICC: 0.89-0.94), the variability of C-arm CT was low (CV: 2.41-6.43%, SD: 0.01-0.048, ICC: 0.65-0.98). Its interreader reliability (CV: 2.66-4.55%, SD: 0.01-0.03, ICC: 0.81-0.95) was comparable to that of HD-MDCT (CV: 2.41-4.08%, SD: 0.014-0.016, ICC: 0.95-0.96), and fpVCT (CV: 3.13-5.63%, SD: 0.009-0.036, ICC: 0.64-0.98) for all parameters except app.TbSp. CONCLUSIONS: C-arm CT is a reliable method for assessing trabecular bone architectural parameters with the exception of app.TbSp due to spatial resolution limitation.

Evaluation of dual-energy CT for differentiating intracerebral hemorrhage from iodinated contrast material staining.

PURPOSE: To evaluate the efficacy of dual-energy computed tomography (CT) in the differentiation of intracerebral hemorrhage (ICH) from iodinated contrast material in patients who received contrast material via intraarterial or intravenous delivery. MATERIALS AND METHODS: This retrospective study was approved by the local institutional review board, which waived the informed consent requirement for the analysis. Sixteen patients with acute stroke and two with head trauma who had undergone intraarterial or intravenous administration of iodinated contrast material were evaluated by using dual-energy CT to differentiate areas of hyperattenuation secondary to contrast material staining from those representing ICH. A dual-energy CT scanner was used for imaging at 80 and 140 kV, and a three-material decomposition algorithm was used to obtain virtual unenhanced images and iodine overlay images. The sensitivity, specificity, and accuracy of dual-energy CT in the prospective differentiation of intraparenchymal contrast material from hemorrhage were obtained. Follow-up images were used as the standard of reference. RESULTS: There were 28 intraparenchymal areas of hyperattenuation classified at dual-energy CT as iodinated contrast material staining (n = 20, 71%), hemorrhage (n = 5, 18%), or both (n = 3, 11%). Two of the three areas of hyperattenuation seen on both virtual unenhanced and iodine overlay images were related to mineralization. The sensitivity, specificity, and accuracy of dual-energy CT in the identification of hemorrhage were 100% (six of six areas), 91% (20 of 22 areas), and 93% (26 of 28 areas), respectively. CONCLUSION: Dual-energy CT can help differentiate ICH from iodinated contrast material staining with high sensitivity and specificity in patients who have recently received intraarterial or intravenous iodinated contrast material.

Women with anorexia nervosa: finite element and trabecular structure analysis by using flat-panel volume CT.

PURPOSE: To use finite element modeling based on flat-panel volume computed tomography (CT) and bone mineral density (BMD) provided by dual-energy x-ray absorptiometry (DXA) to compare bone failure load, stiffness, and trabecular structure in women with anorexia nervosa (AN) and age-matched normal-weight control subjects. MATERIALS AND METHODS: The study was approved by the institutional review board and complied with HIPAA guidelines. Informed consent was obtained. Fourteen women, eight with AN (mean age, 26.6 years) and six control subjects (mean age, 26.3 years), underwent flat-panel volume CT of the distal radius to determine apparent trabecular bone volume fraction (BV/TV), apparent trabecular number (TbN), apparent trabecular thickness (TbTh), and apparent trabecular separation (TbSp). Bone strength and stiffness were calculated from uniaxial compression tests by using finite element models created from flat-panel volume CT. DXA was used to determine BMD of the radius, lumbar spine, and hip. Means ± standard deviations of all variables were calculated for both groups and compared (Student t test). Univariate regression analysis and stepwise regression modeling were performed. RESULTS: Patients with AN had lower values for stiffness (284.77 kN/mm ± 76.14 vs 389.97 kN/mm ± 84.90, P = .04), failure load (4.98 kN ± 1.23 vs 7.01 kN ± 1.52, P = .02), BV/TV (0.32% ± 0.09 vs 0.44% ± 0.02, P = .007), and TbN (1.15 mm(-3) ± 0.20 vs 1.43 mm(-3) ± 0.13, P = .008) and higher values for TbSp (0.62 mm ± 0.20 vs 0.40 mm ± 0.04, P = .02) compared with normal-weight control subjects. TbTh was lower in women with AN (P = .1). BMD measurements were significantly lower for the AN group. BMD measurements and trabecular parameters (except TbTh) correlated with stiffness and failure load (r = 0.58 to 0.83). CONCLUSION: Failure load and stiffness are abnormal in women with AN compared with those in normal-weight control subjects and correlate with BMD and trabecular parameters.

MDCT arthrography assessment of the severity of cartilage damage and scapholunate dissociation in regard to specific-component tears of the scapholunate interosseous ligament.

PURPOSE: To evaluate the distribution and severity of cartilage damage and scapholunate dissociation assessed on multi-detector computer tomography (MDCT) arthrography in a sample of patients with scapholunate interosseous ligament (SLIL) injury, in regard to component-specific tears. METHODS: We retrospectively included 37 patients with SLIL tears and 34 patients without SLIL tears who served as controls, all patients had undergone MDCT arthrography. Morphology of SLIL dorsal and volar components was graded as: normal, partial, or complete tear. Cartilage damage was assessed in 14 distinct regions of the wrist using a semiquantitative modified scoring system. Staging of scapholunate advanced collapse (SLAC) for each patient was based on the distribution of cartilage damage seen on MDCT arthrography. Scapholunate dissociation was measured for each patient at the tenth of a millimeter. The Student's t-test (p) and the Wilcoxon Rank-Sum test (P) were used to compare the different groups. RESULTS: The cartilage damage scores obtained were greater in patients with complete SLIL dorsal component tear than in other patients (p = 0.0019 and P = 0.0018). Scapholunate dissociation was greater in these patients (p = 0.0003 and P = 0.0013). Scapholunate dissociation was also greater in patients with SLAC wrist (p = 0.0004 and P = 0.0012), with a cut-off value of 3.7 mm for diagnosing SLAC (sensitivity 83.3 % and specificity 89.5 %). CONCLUSION: MDCT arthrography assessment shows that the severity of cartilage damage and scapholunate dissociation is greater when the dorsal component of the SLIL is completely ruptured.

A critical appraisal of the quality of adult dual-energy X-ray absorptiometry guidelines in osteoporosis using the AGREE II tool: An EuroAIM initiative.

OBJECTIVES: Dual energy X-ray absorptiometry (DXA) is the most widely used technique to measure bone mineral density (BMD). Appropriate and accurate use of DXA is of great importance, and several guidelines have been developed in the last years. Our aim was to evaluate the quality of published guidelines on DXA for adults. METHODS: Between June and July 2016 we conducted an online search for DXA guidelines, which were evaluated by four independent readers blinded to each other using the AGREE II instrument. A fifth independent reviewer calculated scores per each domain and agreement between reviewers' scores. RESULTS: Four out of 59 guidelines met inclusion criteria and were included. They were published between 2005 and 2014. Three out of four guidelines reached a high level of quality, having at least five domain scores higher than 60%. Domain 1 (Scope and Purpose) achieved the highest result (total score = 86.8 ± 3.7%). Domain 6 (Editorial Independence) had the lowest score (total score = 54.7 ± 12.5%). Interobserver agreement ranged from fair (0.230) to good (0.702). CONCLUSIONS: Overall, the quality of DXA guidelines is satisfactory when evaluated using the AGREE II instrument. The Editorial Independence domain was the most critical, thus deserving more attention when developing future guidelines. MAIN MESSAGES: • Three of four guidelines on DXA had a high quality level (>60%). • Scope/purpose had the highest score (86.8 ± 3.7%). • Editorial Independence had the lowest score (54.7 ± 12.5%). • Interobserver agreement ranged from fair (0.230) to good (0.702).

Characterization of trabecular bone structure from high-resolution magnetic resonance images using fuzzy logic.

The purpose of this work was to apply fuzzy logic image processing techniques to characterize the trabecular bone structure with high-resolution magnetic resonance images. Fifteen ex vivo high-resolution magnetic resonance images of specimens of human radii at 1.5 T and 12 in vivo high-resolution magnetic resonance images of the calcanei of peri- and postmenopausal women at 3 T were obtained. Soft segmentation using fuzzy clustering was applied to MR data to obtain fuzzy bone volume fraction maps, which were then analyzed with three-dimensional (3D) fuzzy geometrical parameters and measures of fuzziness. Geometrical parameters included fuzzy perimeter and fuzzy compactness, while measures of fuzziness included linear index of fuzziness, quadratic index of fuzziness, logarithmic fuzzy entropy, and exponential fuzzy entropy. Fuzzy parameters were validated at 1.5 T with 3D structural parameters computed from microcomputed tomography images, which allow the observation of true trabecular bone structure and with apparent MR structural indexes at 1.5 T and 3 T. The validation was statistically performed with the Pearson correlation coefficient as well as with the Bland-Altman method. Bone volume fraction correlation values (r) were up to .99 (P<.001) with good agreements based on Bland-Altman analysis showing that fuzzy clustering is a valid technique to quantify this parameter. Measures of fuzziness also showed consistent correlations to trabecular number parameters (r>.85; P<.001) and good agreements based on Bland-Altman analysis, suggesting that the level of fuzziness in high-resolution magnetic resonance images could be related to the trabecular bone structure.

Technical limitations of dual-energy CT in neuroradiology: 30-month institutional experience and review of literature.

BACKGROUND: Dual-energy CT (DECT) has been shown to be a useful modality in neuroradiology. OBJECTIVE: To assess failure modes and limitations of DECT in different neuroimaging applications. PATIENTS AND METHODS: Dual-source DECT scans were performed in 72 patients over 30 months to differentiate contrast agent staining or extravasation from intracranial hemorrhage (ICH) (n=40); to differentiate calcium from ICH (n=2); for metal-artifact reduction (n=5); and for angiographic assessment (n=25). A three-material decomposition algorithm was used to obtain virtual non-contrast (VNC) and iodine (or calcium) overlay images. Images were analyzed in consensus by two board-certified radiologists to determine the success of the algorithm and to assess confounding factors. Furthermore, a dilution experiment using cylinders containing defined heparinized swine blood, normal saline, and selected iodine concentrations was conducted to assess other possible confounding factors. RESULTS: Dual-energy analysis was successful in 65 (90.2%) patients. However, the algorithm failed when images were affected by beam hardening (n=3, 4.2%), the presence of a fourth material (parenchymal calcification) (n=3, 4.2%), or motion (n=1, 1.4%). In the dilution experiment, a saturation effect was seen at high iodine concentrations (≥37 mg/ml). VNC and iodine overlay images were not reliable above this concentration, and beam-hardening artifacts were noted. CONCLUSIONS: DECT material decomposition is usually successful in neuroradiology. However, it can only distinguish up to three preselected materials. A fourth material such as parenchymal calcium may confound the analysis. Artifacts such as beam hardening, metallic streak, or saturation effect can also impair material decomposition.

Hormone predictors of abnormal bone microarchitecture in women with anorexia nervosa.

Osteopenia is a complication of anorexia nervosa (AN) associated with a two- to three-fold increase in fractures. Nutritional deficits and hormonal abnormalities are thought to mediate AN-induced bone loss. Alterations in bone microarchitecture may explain fracture risk independent of bone mineral density (BMD). Advances in CT imaging now allow for noninvasive evaluation of trabecular microstructure at peripheral sites in vivo. Few data are available regarding bone microarchitecture in AN. We therefore performed a cross-sectional study of 23 women (12 with AN and 11 healthy controls) to determine hormonal predictors of trabecular bone microarchitecture. Outcome measures included bone microarchitectural parameters at the ultradistal radius by flat-panel volume CT (fpVCT); BMD at the PA and lateral spine, total hip, femoral neck, and ultradistal radius by dual energy X-ray absorptiometry (DXA); and IGF-I, leptin, estradiol, testosterone, and free testosterone levels. Bone microarchitectural measures, including apparent (app.) bone volume fraction, app. trabecular thickness, and app. trabecular number, were reduced (p<0.03) and app. trabecular spacing was increased (p=0.02) in AN versus controls. Decreased structural integrity at the ultradistal radius was associated with decreased BMD at all sites (p

The heart of patients with aortic aneurysms: evidence from cardiac computed tomography.

To determine in patients with abdominal aortic aneurysm (AAA) the coronary calcium burden and prevalence of coronary artery disease (CAD) in relation to cardiovascular risk factors, and to assess the left ventricular (LV) function using cardiac computed tomography (CT). Sixty consecutive patients (six females; 72.2+/-9.0 years) with AAA underwent dual-source CT calcium scoring and coronary angiography prior to AAA repair. In the 60 patients, the Framingham risk score (FRS) ranged from 5-43%. Twenty patients (33%) were at low, 16 (27%) at intermediate, and 24 (40%) at high risk for cardiovascular disease. The median Agatston score (AS) was 393 (0-3538). No significant correlation was found between AS and FRS (P=0.76). 846/851 coronary segments (99%) in 57/60 patients (95%) were depicted with a diagnostic image quality. Significant stenoses were found in 132/846 segments (16%) in 33/60 patients (55%). Five patients (8%) with significant coronary artery stenosis showed reduced LV function [ejection fraction (EF)<50%]. The extent of CAD was significantly correlated with AS (r=0.43, P<0.01), whereas no correlation was found for FRS (P=0.55). Cardiac CT is feasible in patients with AAA and allows for the assessment of coronary calcium, coronary stenoses, and LV function. The calcium burden and coronary stenoses assessment with cardiac CT provides incremental information beyond traditional cardiovascular risk factors alone.

Fuzzy logic structure analysis of trabecular bone of the calcaneus to estimate proximal femur fracture load and discriminate subjects with and without vertebral fractures using high-resolution magnetic resonance imaging at 1.5 T and 3 T.

Newly developed fuzzy logic-derived structural parameters were used to characterize trabecular bone architecture in high-resolution magnetic resonance imaging (HR-MRI) of human cadaver calcaneus specimens. These parameters were compared to standard histomorphological structural measures and analyzed concerning performance in discriminating vertebral fracture status and estimating proximal femur fracture load. Sets of 60 sagittal 1.5 T and 3.0 T HR-MRI images of the calcaneus were obtained in 39 cadavers using a fast gradient recalled echo sequence. Structural parameters equivalent to bone histomorphometry and fuzzy logic-derived parameters were calculated using two chosen regions of interest. Calcaneal, spine, and hip bone mineral density (BMD) measurements were also obtained. Fracture status of the thoracic and lumbar spine was assessed on lateral radiographs. Finally, mechanical strength testing of the proximal femur was performed. Diagnostic performance in discriminating vertebral fracture status and estimating femoral fracture load was calculated using regression analyses, two-tailed t-tests of significance, and receiver operating characteristic (ROC) analyses. Significant correlations were obtained at both field strengths between all structural and fuzzy logic parameters (r up to 0.92). Correlations between histomorphological or fuzzy logic parameters and calcaneal BMD were mostly significant (r up to 0.78). ROC analyses demonstrated that standard structural parameters were able to differentiate persons with and without vertebral fractures (area under the curve [A(Z)] up to 0.73). However, none of the parameters obtained in the 1.5-T images and none of the fuzzy logic parameters discriminated persons with and without vertebral fractures. Significant correlations were found between fuzzy or structural parameters and femoral fracture load. Using multiple regression analysis, none of the structural or fuzzy parameters were found to add discriminative value to BMD alone. In summary significant correlations were obtained at both field strengths between all structural and fuzzy logic parameters. However, fuzzy logic-based calcaneal parameters were not well suited for vertebral fracture discrimination. Although significant correlations were found between fuzzy or structural parameters and femoral fracture load, multiple regression analysis showed limited improvement for estimating femoral failure load in addition to femoral BMD alone. Local femoral measurements are still needed to estimate femoral bone strength. Overall, parameters obtained at 3.0 T performed better than those at 1.5 T.

MR imaging findings in the follow-up of patients with different stages of knee osteoarthritis and the correlation with clinical symptoms.

OBJECTIVE: To assess the rate of cartilage loss, the change in bone marrow edema pattern and internal joint derangement at 1.5-T MRI in patients with knee osteoarthritis and to correlate these findings with the clinical Western Ontario and McMaster University Osteoarthitis (WOMAC) score. METHODS: Forty subjects (mean age 57.7+/-15 years; 16 females and 24 males) were recruited: 6 healthy volunteers (OA0), 17 patients with mild osteoarthritis (OA1) and 17 with severe osteoarthritis (OA2) based on the Kellgren-Lawrence scale. MR scans, radiographs and WOMAC scores were obtained at baseline, first follow-up (1.4+/-0.67 years; n=40) and second follow-up (2.4+/-0.4 years; n=26). Cartilage morphology, bone marrow edema (BME), meniscal and ligamentous pathology were assessed on MR images and quantified by two radiologists in consensus. RESULTS: Full-thickness cartilage lesions were observed in 12/17 OA2 at baseline, in 13/17 at the first follow-up and in 7/10 at the second follow-up. Cartilage loss was found in eight patients at the first follow-up and five at the second follow-up. BME was observed in 23/40 patients at baseline, in 22/40 at the first follow-up and in 12/26 at the second follow-up. Changes in BME were visualized in 19/22 and 4/13 patients at the first and second follow-up, respectively. Changes in WOMAC scores over time did not correlate significantly with the amount of cartilage loss and the change in BME (P>0.05). CONCLUSION: MRI is well suited to monitor the progression of OA in the longitudinal follow-up since it shows cartilage defects, BME and internal joint derangement, pathologies that are not visualized by radiographs. The lack of significant correlation between MRI findings and clinical findings is not unexpected, has been previously described and may in part be due to the fact that patients get more accustomed to their pain as the knee progressively degenerates.

Trabecular bone structure of the calcaneus: comparison of MR imaging at 3.0 and 1.5 T with micro-CT as the standard of reference.

PURPOSE: To investigate in vitro the calcaneal trabecular bone structure in elderly human donors with high spatial resolution magnetic resonance (MR) imaging at 3.0 T and 1.5 T, to quantitatively compare MR measures of bone microarchitecture with those from micro-computed tomography (CT), and to compare the performance of 3.0-T MR imaging with that of 1.5-T MR imaging in differentiating donors with spinal fractures from those without spinal fractures. MATERIALS AND METHODS: The study was performed in line with institutional and legislative requirements; all donors had dedicated their body for educational and research purposes prior to death. Sagittal MR images of 49 human calcaneus cadaveric specimens were obtained (mean age of donors, 79.5 years +/- 11 [standard deviation]; 26 male donors, 23 female donors). After the spatial coregistering of images acquired at 3.0-T and 1.5-T MR imaging, the signal-to-noise-ratios and structural parameters obtained at each magnetic field strength were compared in corresponding sections. Micro-CT was performed on calcaneus cores obtained from corresponding regions in 40 cadaveric specimens. Vertebral deformities of the thoracic and lumbar spine were radiographically classified by using the spinal fracture index. Diagnostic performance of the structural parameters in differentiating donors with vertebral fractures from those without was assessed by using receiver operator characteristic (ROC) analysis, including area under the ROC curve (A(z)). RESULTS: Correlations between structural parameters at 3.0-T MR imaging and those at micro-CT were significantly higher (P < .05) than correlations between structural parameters at 1.5-T MR imaging and those at micro-CT (trabecular thickness, r = 0.76 at 3.0 T vs r = 0.57 at 1.5 T). Trabecular dimensions were amplified at 3.0 T because of increasing susceptibility artifacts. Also, higher ROC values were found for structural parameters at 3.0 T than at 1.5 T, but differences were not significant (trabecular thickness, A(z) = 0.75 at 3.0 T vs A(z) = 0.66 at 1.5 T, P > .05). CONCLUSION: MR imaging at 3.0 T provided a better measure of the trabecular bone structure than did MR imaging at 1.5 T. There was a trend for better differentiation of donors with from those without osteoporotic vertebral fractures at 3.0 T than at 1.5 T.

Cartilage MR imaging at 3.0 versus that at 1.5 T: preliminary results in a porcine model.

PURPOSE: To compare 1.5- and 3.0-T magnetic resonance (MR) images of porcine knee specimens containing artificial cartilage lesions in terms of accuracy of lesion depiction, image quality, and signal-to-noise ratio (SNR). MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act-compliant study had institutional review board approval, and informed consent was obtained from the human volunteers. Two fat-saturated cartilage MR imaging sequences (an intermediate-weighted fast spin-echo [SE] sequence and a spoiled gradient-echo [GRE] sequence) were optimized for imaging at 3.0 T in two human volunteers and then used to image 10 porcine knees in which 29 artificial cartilage lesions had been created. Corresponding sequences were used at 1.5 T for all specimens. Images were assessed by two radiologists in consensus, and diagnostic performance in lesion depiction was determined by using macroscopic findings in specimen slices as a reference standard. SNRs were also calculated. For statistical analysis, the McNemar test of discordant pairs was used with a level of significance of P < .05. RESULTS: The best diagnostic performance for both the intermediate-weighted fast SE and the spoiled GRE sequences was achieved at 3.0 T. With use of corresponding fat-saturated intermediate-weighted fast SE sequences with an identical acquisition time (9 minutes 44 seconds), 26 (90%) of 29 lesions were detected at 3.0 T, while 18 (62%) were detected at 1.5 T. With use of fat-saturated spoiled GRE sequences, 24 (83%) of 29 lesions were detected at 3.0 T (acquisition time, 8 minutes 48 seconds), and 23 (79%) lesions were detected at 1.5 T (acquisition time, 11 minutes 14 seconds). The rate of correct lesion grade assessment was 65% (17 of 26 lesions) at 3.0 T and 61% (11 of 18 lesions) at 1.5 T with the intermediate-weighted fast SE sequences and 83% (20 of 24 lesions) at 3.0 T and 70% (16 of 23 lesions) at 1.5 T with the spoiled GRE sequences. Both subjective evaluation of image quality and SNR values were significantly higher at 3.0 T (P < .05). CONCLUSION: In this animal model, MR imaging at 3.0 T increased the accuracy of cartilage lesion assessment when compared with imaging at 1.5 T. Image quality and SNR were highest at 3.0 T.