Contrast-enhanced magnetic resonance imaging identifies focal regions of intramyocardial fibrosis, in patients with severe aortic valve disease: Correlation with quantitative histopathology

Background Chronic aortic valve disease (AVD) is characterized by progressive accumulation of interstitial myocardial fibrosis (MF). However, assessment of MF accumulation has only been possible through histologic analyses of endomyocardial biopsies. We sought to evaluate contrast-enhanced magnetic resonance imaging (ce-MRI) as a noninvasive method to identify the presence of increased MF in patients with severe AVD. Methods Seventy patients scheduled to undergo aortic valve replacement surgery were examined by cine and ce-MRI in a 1.5-T scanner. Cine images were used for the assessment of left ventricular (LV) volumes, mass, and function. Delayed-enhancement images were used to characterize the regions of MF. In addition, histologic analyses of myocardial samples obtained during aortic valve replacement surgery were used for direct quantification of interstitial MF. Ten additional subjects who died of noncardiac causes served as controls for the quantitative histologic analyses. Results Interstitial MF determined by histopathologic analysis was higher in patients with AVID than in controls (2.7% +/- 2.0% vs 0.6% +/- 0.2%, P =.001). When compared with histopathologic results, ce-MRI demonstrated a sensitivity of 74%, a specificity of 81%, and an accuracy of 76% to identify AVD patients with increased interstitial MF There was a significant inverse correlation between interstitial MF and LV ejection fraction (r = -0.67, P <.0001). Accordingly, patients with identifiable focal regions of MF by ce-MRI exhibited worse LV systolic function than those without MF (45% +/- 14% vs 65% +/- 14%, P <.0001). Conclusions Contrast-enhanced MRI allows for the noninvasive detection of focal regions of MF in patients with severe AVD. Moreover, patients with identifiable MF by ce-MRI exhibited worse LV functional parameters. (Am Heart J 2009; 157:361-8.)

No correlation and low agreement of imaging and inflammatory atherosclerosis` markers in familial hypercholesterolemia

Our purpose was to study the determinants of coronary and carotid subclinical atherosclerosis, aortic stiffness and their relation with inflammatory biomarkers in familial hypercholesterolemia (FH) subjects. Furthermore, we evaluated the agreement degree of imaging and inflammatory markers` severity used for coronary heart disease (CHD) prediction. Coronary calcium scores (CCS), carotid intima media thickness (IMT), carotid-femoral pulse wave velocity (PWV), C reactive protein (CRP) and white blood cells count (WBC) were determined in 89 FH patients (39 +/- 14 years, mean LDL-C=279 mg/dl) and in 31 normal subjects (NL). The following values were considered as imaging and biomarkers` severity: CCS > 75th% for age and sex, IMT > 900 mu m, PWV > 12 m/s, and CRP > 3 mg/l. Coronary artery calcification (CAC) prevalence and severity, IMT, PWV and WBC values were higher in FH than in NL (all parameters, p < 0.05). After multivariate analysis, the following variables were considered independent determinants of (1) IMT: systolic blood pressure, 10-year CHD risk by Framingham risk scores (FRS) and apolipoprotein B (r(2)=0.33); (2) PWV: age (r(2)=0.35); (3) CAC as a continuous variable: male gender and LDL-cholesterol year score (LYS) (r(2)=0.32); (4) presence of CAC as dichotomous variable: FRS (p=0.0027) and LYS (p=0.0228). With the exception of a moderate agreement degree between IMT and PWV severity (kappa=0.5) all other markers had only a slight agreement level (kappa < 0.1). In conclusion, clinical parameters poorly explained IMT, CAC and PWV variability in FH subjects. Furthermore, imaging markers and inflammatory biomarkers presented a poor agreement degree of their severity for CHD prediction. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

Quantitative and qualitative comparison of 3.0 T and 1.5 T MR imaging of the liver in patients with diffuse parenchymal liver disease

Purpose: The purpose of our study was to compare signal characteristics and image qualities of MR imaging at 3.0 T and 1.5 T in patients with diffuse parenchymal liver disease. Materials and methods: 25 consecutive patients with diffuse parenchymal liver disease underwent abdominal MR imaging at both 3.0 T and 1.5 T within a 6-month interval. A retrospective study was conducted to obtain quantitative and qualitative data from both 3.0 T and 1.5 T MRI. Quantitative image analysis was performed by measuring the signal-to-noise ratios (SNRs) and the contrast-to-noise ratios (CNRs) by the Students t-test. Qualitative image analysis was assessed by grading each sequence on a 3- and 4-point scale, regarding the presence of artifacts and image quality, respectively. Statistical analysis consisted of the Wilcoxon signed-rank test. Results: the mean SNRs and CNRs of the liver parenchyma and the portal vein were significantly higher at 3.0 T than at 1.5 T on portal and equilibrium phases of volumetric interpolated breath-hold examination (VIBE) images (P < 0.05). The mean SNRs were significantly higher at 3.0 T than at 1.5 T on T1-weighted spoiled gradient echo (SGE) images (P < 0.05). However, there were no significantly differences on T2-weighted short-inversion-time inversion recovery (STIR) images. Overall image qualities of the 1.5 T noncontrast T1- and T2-weighted sequences were significantly better than 3.0 T (P < 0.01). In contrast, overall image quality of the 3.0 T post-gadolinium VIBE sequence was significantly better than 1.5 T (P< 0.01). Conclusions: MR imaging of post-gadolinium VIBE sequence at 3.0 T has quantitative and qualitative advantages of evaluating for diffuse parenchymal liver disease. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Ultrasonographic Evaluation of Achilles Tendon Repair After Percutaneous Sectioning for the Correction of Congenital Clubfoot Residual Equinus

Background: Most cases of congenital clubfoot treated with the Ponseti technique require percutaneous Achilles tenotomy to correct the residual equinus. Clinical evidence suggests that complete healing occurs between the cut tendon stumps, but there have not yet been any detailed studies investigating this reparative process. This study was performed to assess Achilles tendon repair after percutaneous section to correct the residual equinus of clubfoot treated with the Ponseti method. Method: A prospective study analyzed 37 tenotomies in 26 patients with congenital clubfoot treated with the Ponseti technique, with a minimum follow-up of 1 year after the section. The tenotomy was performed percutaneously with a large-bore needle bevel with patient sedation and local anesthesia. Ultrasonographic scanning was performed after section to ascertain that the tenotomy had been completed and to measure the stump separation. In the follow-up period, the reparative process was followed ultrasonographically and assessed at 3 weeks, 6 months, and 1 year posttenotomy. Results: The ultrasonography performed immediately after the procedure showed that in some cases, residual strands between the tendon ends persisted, and these were completely sectioned under ultrasound control. A mean retraction of 5.65 mm +/- 2.26 mm (range, 2.3 to 11.0 mm) between tendon stumps after section was observed. Unusual bleeding occurred in one case and was controlled by digital pressure, with no interference with the final treatment. After 3 weeks, ultrasonography showed tendon repair with the tendon gap filled with irregular hypoechoic tissue, and also with transmission of muscle motion to the heel. Six months after tenotomy, there was structural filling with a fibrillar aspect, mild or moderate hypoechogenicity, and tendon scar thickening when compared with a normal tendon. One year after tenotomy, ultrasound showed a fibrillar structure and echogenicity at the repair site that was similar to a normal tendon, but with persistent tendon scarring thickness. Conclusions: There is a fast reparative process after Achilles tendon percutaneous section that reestablishes continuity between stumps. The reparative tissue evolved to tendon tissue with a normal ultrasonographic appearance except for mild thickening, suggesting a predominantly intrinsic repair mechanism.

Water excitation MPRAGE: An alternative sequence for postcontrast imaging of the abdomen in noncooperative patients at 1.5 Tesla and 3.0 Tesla MRI

Purpose: To evaluate the diagnostic image quality of post-gadolinium water excitation-magnetization-prepared rapid gradient-echo (WE-MPRAGE) sequence in abdominal examinations of noncooperative patients at 1.5 Tesla (T) and 3.0T MRI. Materials and Methods: Eighty-nine consecutive patients (48 males and 41 females; mean age +/- standard deviation, 54.6 +/- 16.6 years) who had MRI examinations including postgadolinium WE-MPRAGE were included in the study. Of 89 patients, 33 underwent noncooperative protocol at 1.5T. 10 under-went noncooperative protocol at 3.0T, and 46 underwent cooperative protocol at 3.0T. Postgadolinium WE-MPRAGE, MPRAGE, and three-dimensional gradient-echo sequences of these three different groups were qualitatively evaluated for image quality, extent of artifacts, lesion conspicuity, and homogeneity of fat-attenuation by two reviewers retrospectively, independently, and blindly. The results were compared using Wilcoxon signed rank and Mann-Whitney U tests. Kappa statistics were used to measure the extent of agreement between the reviewers. Results: The average scores indicated that the images were diagnostic for WE-MPRAGE at 1.5T and 3.0T in noncooperative patients. WE-MPRAGE achieved homogenous fat-attenuation in 31/33 (94%) of noncooperative patients at 1.5T and 10/10 (100%) of noncooperative patients at 3.0T. WE-MPRAGE at 3.0T had better results for image quality, extent of artifacts, lesion conspicuity and homogeneity of fat-attenuation compared with WE-MPRAGE at 1.5T. in noncooperative patients (P = 0.0008, 0.0006, 0.0024, and 0.0042: respectively). Kappa statistics varied between 0.76 and 1.00, representing good to excellent agreement. Conclusion: WE-MPRAGE may be used as a T1-weighted postgadolinium fat-attenuated sequence in noncooperative patients, particularly at 3.0T MRI.

Kallmann syndrome and mirror movements: White matter quantitative evaluation with magnetic resonance imaging

Kallmann syndrome (KS), characterized by the association of hypogonadotropic hypogonadism and anosmia, may present many other phenotypic abnormalities, including neurologic features as involuntary movements, called mirror movements (MM). MM etiology probably involves a complex mechanism comprising corticospinal tract abnormal development associated with deficient contralateral motor cortex inhibitory system. In this study, in order to address previous hypotheses concerning MM etiology, we identified and quantified white matter (WM) alterations in 21 KS patients, comparing subjects with and without MM and 16 control subjects, using magnetization transfer ratio (MTR) and T2 relaxometry (R2). Magnetization transfer and 12 double-echo images were acquired in a 1.5 T system. MTR and R2 were calculated pixel by pixel to initially create individual maps, and then, group average maps, co-registered with MNI305 stereotaxic coordinate system. After analysis of selected regions of interest, we demonstrated areas with higher 12 relaxation time and lower MTR values in KS patients, with and without MM, differently involving corticospinal tract projection, frontal lobes and corpus callosum. Higher MTR was observed only in pyramidal decussation when compared in both groups of patients with controls. In conclusion, we demonstrated that patients with KS have altered WM areas, presenting in a different manner in patients with and without MM. These data suggest axonal loss or disorganization involving abnormal pyramidal tracts and other associative/connective areas, relating to the presence or absence of MM. We also found a different pattern of alteration in pyramidal decussation, which can represent the primary area of neuronal disarrangement. (C) 2010 Elsevier B.V. All rights reserved.

Advances in Imaging of Osteoarthritis and Cartilage

Osteoarthritis (OA) is the most frequent form of arthritis, with major implications for individual and public health care without effective treatment available. The field of joint imaging, and particularly magnetic resonance (MR) imaging, has evolved rapidly owing to technical advances and the application of these to the field of clinical research. Cartilage imaging certainly is at the forefront of these developments. In this review, the different aspects of OA imaging and cartilage assessment, with an emphasis on recent advances, will be presented. The current role of radiography, including advances in the technology for joint space width assessment, will be discussed. The development of various MR imaging techniques capable of facilitating assessment of cartilage morphology and the methods for evaluating the biochemical composition of cartilage will be presented. Advances in quantitative morphologic cartilage assessment and semiquantitative whole-organ assessment will be reviewed. Although MR imaging is the most important modality in imaging of OA and cartilage, others such as ultrasonography play a complementary role that will be discussed briefly.

Magnetic Resonance Imaging Assessment of Subchondral Bone and Soft Tissues in Knee Osteoarthritis

Knee osteoarthritis (OA) has to be considered a whole joint disease. Magnetic resonance imaging (MRI) allows superior assessment of all joint tissues that may be involved in OA, such as the subchondral bone, synovium, ligaments, and periarticular soft tissues. Reliable MRI-based scoring systems are available to assess and quantify these structures and associated pathology. Cross-sectional and longitudinal evaluation has enabled practitioners to understand their relevance in explaining pain and structural progression.

Lower uterine segment thickness measurement in pregnant women with previous Cesarean section: reliability analysis using two- and three-dimensional transabdominal and transvaginal ultrasound

Objective To evaluate the reliability of two- and three-dimensional ultrasonographic measurement of the thickness of the lower uterine segment (LUS) in pregnant women by transvaginal and transabdominal approaches. Methods This was a study of 30 pregnant women who bad bad at least one previous Cesarean section and were between 36 and 39 weeks` gestation, with singleton pregnancies in cephalic presentation. Sonographic examinations were performed by two observers using both 4-7-MHz transabdominal and 5-8-MHz transvaginal volumetric probes. LUS measurements were performed using two- and three-dimensional ultrasound, evaluating the entire LUS thickness transabdominally and the LUS muscular thickness transvaginally. Each observer measured the LUS four times by each method. Reliability was analyzed by comparing the mean of the absolute differences, the intraclass correlation coefficients, the 95% limits of agreement and the proportion of differences <1 mm. Results Transvaginal ultrasound provided greater reliability in LUS measurements than did transabdominal ultrasound. The use of three-dimensional ultrasound improved significantly the reliability of the LUS muscular thickness measurement obtained transvaginally. Conclusions Ultrasonographic measurement of the LUS muscular thickness transvaginally appears more reliable than does that of the entire LUS thickness transabdominally. The use of three-dimensional ultrasound should be considered to improve measurement reliability. Copyright (c) 2009 ISUOG. Published by John Wiley & Sons, Ltd.

Magnetic Resonance Imaging in Knee Osteoarthritis Research: Semiquantitative and Compositional Assessment

Semiquantitative assessment of the knee by expert magnetic resonance imaging readers is a powerful research tool for understanding the natural history of osteoarthritis (OA). Several reliable semiquantitative scoring systems have been applied to large observational cross-sectional and longitudinal epidemiologic studies and interventional clinical trials. Such evaluations have enabled understanding of the relevance of disease in structures within the knee joint to explain pain and progression of OA. Compositional imaging of cartilage has added to our ability to detect early degeneration before morphologic changes are present, which may help to prevent the permanent morphologic changes commonly seen in knee OA.

Imaging in osteoarthritis: what have we learned and where are we going?

Osteoarthritis (OA) is a widely prevalent disease of the whole joint including cartilage, bone and soft tissues. Increasing importance of imaging including assessment of all joint structures has been recognized recently. Conventional radiography is still the first and most commonly used imaging technique for evaluation of a patient with a known or suspected diagnosis of OA. However, limitations have been revealed by recent MRI-based knee OA studies. MRI plays a crucial role in understanding the natural history of the disease and in guiding future therapies due to its ability to image the knee as a whole organ and to directly and three-dimensionally assess cartilage morphology and composition. It is crucial to use the appropriate MR pulse sequences to assess various OA features, and thus support from experienced musculoskeletal radiologists should be sought for study design, image acquisition and interpretation. The aim of this article is to describe the roles and limitations of conventional radiography and MRI in imaging of OA, and also to give insight into the use of other modalities such as ultrasound, scintigraphy, computed tomography (CT) and CT arthrography in clinical practice and research in OA, particularly focusing on the assessment of knee OA in the tibiofemoral joint.

Articular Cartilage in the Knee: Current MR Imaging Techniques and Applications in Clinical Practice and Research

Magnetic resonance (MR) imaging is the most important imaging modality for the evaluation of traumatic or degenerative cartilaginous lesions in the knee. It is a powerful noninvasive tool for detecting such lesions and monitoring the effects of pharmacologic and surgical therapy. The specific MR imaging techniques used for these purposes can be divided into two broad categories according to their usefulness for morphologic or compositional evaluation. To assess the structure of knee cartilage, standard spin-echo (SE) and gradient-recalled echo (GRE) sequences, fast SE sequences, and three-dimensional SE and GRE sequences are available. These techniques allow the detection of morphologic defects in the articular cartilage of the knee and are commonly used in research for semiquantitative and quantitative assessments of cartilage. To evaluate the collagen network and proteoglycan content in the knee cartilage matrix, compositional assessment techniques such as T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage (or dGEMRIC), T1 rho imaging, sodium imaging, and diffusion-weighted imaging are available. These techniques may be used in various combinations and at various magnetic field strengths in clinical and research settings to improve the characterization of changes in cartilage. (C)RSNA, 2011 , radiographics.rsna.org

Magnetic resonance imaging quantification of regional cerebral blood flow and cerebrovascular reactivity to carbon dioxide in normotensive and hypertensive rats

Hypertension afflicts 25% of the general population and over 50% of the elderly. In the present work, arterial spin labeling MRI was used to non-invasively quantify regional cerebral blood flow (CBE), cerebrovascular resistance and CO(2) reactivity in spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY), at two different ages (3 months and 10 months) and under the effects of two anesthetics, alpha-chloralose and 2% isoflurane (1.5 MAC). Repeated CBE measurements were highly consistent, differing by less than 10% and 18% within and across animals, respectively. Under alpha-chloralose, whole brain CBE at normocapnia did not differ between groups (young WKY: 61 3 ml/100 g/min; adult WKY: 62 +/- 4 ml/100 g/min; young SHR: 70 +/- 9 ml/100 g/min: adult SHR: 69 8 ml/100 g/min), indicating normal cerebral autoregulation in SHR. At hypercapnia, CBE values increased significantly, and a linear relationship between CBE and PaCO(2) levels was observed. In contrast, 2% isoflurane impaired cerebral autoregulation. Whole brain CBE in SHR was significantly higher than in WKY rats at normocapnia (young SHR: 139 +/- 25 ml/100 g/min; adult SHR: 104 +/- 23 ml/100 g/min; young WKY: 55 +/- 9 ml/100 g/min; adult WKY: 71 +/- 19 ml/100 g/min). CBE values increased significantly with increasing CO(2): however, there was a clear saturation of CBF at PaCO(2) levels greater than 70 mm Hg in both young and adult rats, regardless of absolute CBE values, suggesting that isoflurane interferes with the vasoclilatory mechanisms of CO(2). This behavior was observed for both cortical and subcortical structures. Under either anesthetic, CO(2) reactivity values in adult SHR were decreased, confirming that hypertension, when combined with age, increases cerebrovascular resistance and reduces cerebrovascular compliance. Published by Elsevier Inc.