Ultrasound detection of heel enthesitis: a comparison with magnetic resonance imaging

OBJECTIVE: Seronegative arthropathies are associated with inflammatory enthesopathy. The involvement of Achilles tendon and plantar aponeurosis is common, with strong tendency toward fibrosis and calcification. This study tests the diagnostic efficacy of ultrasound (US) in depicting enthesitis, and compares sonographic images with magnetic resonance images (MRI). METHODS: We studied 32 patients with a diagnosis of seronegative arthropathies, 22 men, 10 women, mean age 29 years. They had heel enthesopathy without typical conventional radiographic evidence. T1 and T2 weighted and short-tau inversion recovery (STIR) MRI sequences were obtained in axial and sagittal planes. An HDI 3000 ATL US device equipped with 12 MHz linear transducer was used to examine the enthesis. Three independent observers assessed the reliability of sonographic images by using video recording of the US examinations. RESULTS: US images of enthesitis showed loss of normal fibrillar echotexture of tendon (100%), lacking the homogeneous pattern, with blurring of tendon margins (56.2%) and irregular fusiform thickening (84.3%). The affected tendons showed intratendinous lesions with ill defined focal tendon defects filled with a mixture of fluid, fat, and/or granulation tissue, with loss of their tightly packed echogenic dots. MRI showed tendon enlargement (62.5%) with loss of the normal flattened hypointense appearance, focal thickening and rounded configuration at the insertion site (31.2%), intermediate T1 and high T2 signals, and diminished signals within the pre-Achilles fat pad due to inflammatory edema. Among all patients, 40.6% developed osteitis. CONCLUSION: MRI was not sensitive compared to US in detecting early changes of enthesopathy. Fatty degeneration appeared late in MRI, while it was detected earlier using US. MRI was not able to detect any calcification process at the insertion site, while US images clearly showed the very early signs of the calcification process. We recommend use of US for early diagnosis and in treatment and followup of patients with tendon enthesopathy, to accurately identify and diagnose different pathologic and biomechanical changes.     

Bone scintigraphy in chronic knee pain: comparison with magnetic resonance imaging

OBJECTIVE: To compare increased bone uptake of 99Tcm-MDP and magnetic resonance (MR) detected subchondral lesions, osteophytes, and cartilage defects in the knee in middle aged people with long-standing knee pain. METHODS: Fifty eight people (aged 41-58 years, mean 50) with chronic knee pain, with or without radiographic knee osteoarthritis, were examined with bone scintigraphy. The pattern and the grade of increased bone uptake was assessed. On the same day, a MR examination on a 1.0 T imager was performed. The presence and the grade of subchondral lesions, osteophytes, and cartilage defects were registered. RESULTS: The kappa values describing the correlation between increased bone uptake and MR detected subchondral lesions varied between 0.79 and 0.49, and between increased bone uptake and MR detected osteophytes or cartilage defects the values were < 0.54. The kappa values describing the correlation between the grade of bone uptake and the grade of the different MR findings was < 0.57. CONCLUSIONS: Good agreement was found between increased bone uptake and MR detected subchondral lesion. The agreement between increased bone uptake and osteophytes or cartilage defects was in general poor as well as the agreement between the grade of bone uptake and the grade of the MR findings.     

Ultrasound and magnetic resonance imaging of healthy paediatric ankles and knees: a baseline for comparison with haemophilic joints

The study was undertaken to document cartilage and soft tissue changes/findings in ankles and knees of normal children of different age groups to be used for comparison in the assessment of children with haemophilia. Cartilage thickness and soft tissue changes were recorded at predetermined sites of ankles/knees on both US and MRI in healthy boys in three age groups: 7–9; 10–14; and 15–18 years. To assess the validity of the ultrasound and MRI measurements, an ex vivo study was done using agar phantoms with techniques and scanners similar to those applied in vivo. Twenty (48%) knees and 22 (52%) ankles of 42 boys, were evaluated. There was a reduction in the thickness of joint cartilage with age. A difference in cartilage measurements was noted in most sites between the age groups on both US and MRI (P < 0.05 each), but such difference was not noted for joint fluid in ankles or knees (P = 0.20, P = 0.68 or P = 0.75, P = 0.63 for US, MRI, respectively). Although cartilage measurements were smaller on US than on MRI for both ankles and knees (P < 0.05 each), this observation was not recorded for fluid in knees (P = 0.02). For diminutive measurements (2 mm) mean US measurements were smaller than corresponding phantom's measurements, P = 0.02. Age‐related measurements were noted for cartilage thickness on US and MRI in ankles and knees. US measurements were smaller than corresponding MRI measurements at most joint sites, which were supported by results on small‐diameter phantoms.     

Dipyridamole magnetic resonance imaging: a comparison with thallium-201 emission tomography

Limitation of space and motion artefact make magnetic resonance imaging during dynamic exercise difficult. Pharmacological stress with dipyridamole can be used as an alternative to exercise for thallium scanning. Forty patients with a history of angina and an abnormal exercise electrocardiogram were studied by dipyridamole thallium myocardial perfusion tomography and dipyridamole magnetic resonance wall motion imaging with a cine gradient refocused sequence. Images for both scans were obtained in the oblique horizontal and vertical long axis and short axis planes before and after pharmacological stress with dipyridamole. The myocardium was divided into nine segments for direct comparison of perfusion with wall motion. Segments were assessed visually into grades--normal, hypokinesis or reduced perfusion, and akinesis or very reduced perfusion. After dipyridamole there were reversible wall motion abnormalities in 24 (62%) of 39 patients with coronary artery disease and 24 (67%) of 36 patients with reversible thallium defects. The site of wall motion deterioration was always the site of a reversible thallium defect. Thallium defects affecting more than two segments were always associated with wall motion deterioration but most single segment thallium defects were undetected by magnetic resonance imaging. There was a significant correlation between detection of wall motion abnormality, the angiographic severity of coronary artery disease, and the induction of chest pain by dipyridamole. There were no significant differences in ventricular volume or ejection fraction changes after dipyridamole between the groups with and without detectable reversible wall motion changes but the normalised magnetic resonance signal intensity of the abnormally moving segments was significantly less than the signal intensity of the normal segments. In nine patients the change was apparent visually and it was maximal in the subendocardial region. Magnetic resonance imaging of reversible wall motion abnormalities in patients with coronary artery disease is feasible during pharmacological stress with dipyridamole and may be associated with a reduced magnetic resonance signal. The failure to show wall motion abnormalities in all cases of reversible thallium defects may be because the defect was small or because dipyridamole caused perfusion defects in the absence of myocardial ischaemia.     

Dipyridamole magnetic resonance imaging: a comparison with thallium-201 emission tomography.

Limitation of space and motion artefact make magnetic resonance imaging during dynamic exercise difficult. Pharmacological stress with dipyridamole can be used as an alternative to exercise for thallium scanning. Forty patients with a history of angina and an abnormal exercise electrocardiogram were studied by dipyridamole thallium myocardial perfusion tomography and dipyridamole magnetic resonance wall motion imaging with a cine gradient refocused sequence. Images for both scans were obtained in the oblique horizontal and vertical long axis and short axis planes before and after pharmacological stress with dipyridamole. The myocardium was divided into nine segments for direct comparison of perfusion with wall motion. Segments were assessed visually into grades--normal, hypokinesis or reduced perfusion, and akinesis or very reduced perfusion. After dipyridamole there were reversible wall motion abnormalities in 24 (62%) of 39 patients with coronary artery disease and 24 (67%) of 36 patients with reversible thallium defects. The site of wall motion deterioration was always the site of a reversible thallium defect. Thallium defects affecting more than two segments were always associated with wall motion deterioration but most single segment thallium defects were undetected by magnetic resonance imaging. There was a significant correlation between detection of wall motion abnormality, the angiographic severity of coronary artery disease, and the induction of chest pain by dipyridamole. There were no significant differences in ventricular volume or ejection fraction changes after dipyridamole between the groups with and without detectable reversible wall motion changes but the normalised magnetic resonance signal intensity of the abnormally moving segments was significantly less than the signal intensity of the normal segments. In nine patients the change was apparent visually and it was maximal in the subendocardial region. Magnetic resonance imaging of reversible wall motion abnormalities in patients with coronary artery disease is feasible during pharmacological stress with dipyridamole and may be associated with a reduced magnetic resonance signal. The failure to show wall motion abnormalities in all cases of reversible thallium defects may be because the defect was small or because dipyridamole caused perfusion defects in the absence of myocardial ischaemia.     

Head-to-head comparison between contrast-enhanced magnetic resonance imaging and dobutamine magnetic resonance imaging in men with ischemic cardiomyopathy

Contrast-enhanced magnetic resonance imaging (MRI) can predict functional recovery after revascularization. Segments with small, subendocardial scars have a large likelihood of recovery, and segments with transmural infarction have a small likelihood of recovery. Segments with an intermediate extent of infarction have an intermediate likelihood of recovery, and therefore, additional information is needed. Accordingly, the transmurality of infarction on contrast-enhanced MRI was compared with low-dose dobutamine MRI to further define viability in 48 patients. Regional contractile dysfunction was determined by cine MRI at rest (17-segment model), and contractile reserve was determined using low-dose dobutamine infusion. Contrast-enhanced MRI was performed to assess the extent of scar tissue. A total of 338 segments (41%) were dysfunctional, with 61% having contractile reserve. Most segments (approximately 75%) with small, subendocardial scars (hyperenhancement scores 1 or 2) had contractile reserve, whereas contractile reserve was not frequently (17%) observed in segments with transmural infarction (hyperenhancement score 4) (p <0.05). Of segments with an intermediate infarct transmurality (hyperenhancement score 3), contractile reserve was observed in 42%, whereas 58% did not have contractile reserve. In conclusion, the agreement between contrast-enhanced MRI and low-dose dobutamine MRI is large in the extremes (subendocardial scars and transmural scars), and contrast-enhanced MRI may be sufficient to assess the likelihood of the recovery of function after revascularization. However, 61% of segments with an intermediate extent of scar tissue on MRI have contractile reserve and 39% lack contractile reserve. In these segments, low-dose dobutamine MRI may be needed to optimally differentiate myocardium with large and small likelihoods of functional recovery after revascularization.     

Bone scintigraphy for osteonecrosis of the knee in patients with non-traumatic osteonecrosis of the femoral head: comparison with magnetic resonance imaging

OBJECTIVE: To determine whether technetium bone scintigraphy (BS) is useful for screening of non-traumatic osteonecrosis of the knee (ONK), which was a major affected site, secondary to the femoral head, among multiple osteonecrosis, in patients with non-traumatic osteonecrosis of the femoral head (ONFH). METHODS: A total of 214 knee joints in 107 patients with ONFH were evaluated by BS and a comparison made with magnetic resonance imaging (MRI). ONK was classified into five sites, including the femoral condyles (ONFC), distal femoral metaphysis (ONFM), tibial plateau (ONTP), proximal tibial metaphysis (ONTM), and patella (ONP). RESULTS: Based on the diagnosis by MRI, ONK was detected in 103 knees of 62 patients (48%). ONFC was most common (86 knees, 40%), ONFM (15%), followed by ONTM (10%), ONP (3%), and ONTP (0.9%). Sensitivity, specificity, and accuracy of BS for ONFC detection were 63%, 71%, and 68%, respectively. When the ONFC lesions on the coronal views of MRI were large or medium sized and occupied two thirds, or the entire anteroposterior joint surface on the sagittal views, the sensitivity of BS for ONFC detection increased to 89% (34/38 knees). The sensitivity of BS for ONFM, ONTM, and ONP detection was 3%, 0%, and 0%, respectively, but these lesions showed a low likelihood of collapse. CONCLUSION: BS is useful for screening large ONK in patients with ONFH given that 89% of patients with ONFC who had a high risk of collapse of the knee were identified.     

Efficacy of radiosynovectomy of the knee in rheumatoid arthritis: Evaluation with magnetic resonance imaging

The intra-articular injection of a radiopharmaceutical agent (radiosynovectomy) produces a reduction of the synovial inflammatory process. The inflammed synovial membrane can be identified with magnetic resonance imaging after the intravenous administration of gadolinium (MRI-Gd). A 6-month prospective study was carried out in 10 patients with rheumatoid arthritis after radiosynovectomy of the knee. The efficacy was evaluated with clinical parameters and MRI-Gd. A progressive amelioration of synovial effusion, pain, articular range of mobility, total leucocytes count in synovial fluid and synovial membrane thickness through MRI-Gd was observed. The global efficacy was considered to be good in six patients, fair in three and bad in one. The study shows for the first time that MRI-Gd allows the evaluation of the response of the synovial membrane to radiosynovectomy.     

心脏磁共振与核医学负荷心肌灌注显像探测冠心病心肌缺血的对比研究

目的:对比心脏磁共振成像(CMR)与核医学单光子计算机断层扫描(SPECT)负荷心肌灌注显像探测冠心病心肌缺血的诊断效能。方法:前瞻性入选51例疑似或确诊冠心病患者,所有患者在冠状动脉造影(CAG)检查之前或之后4周内进行了CMR和SPECT负荷心肌灌注显像,三种检查之间无任何再血管化治疗。以CAG作为参考标准,将CMR与SPECT分析结果进行比较,计算其诊断效能。结果:基于患者个体分析,CMR和SPECT负荷心肌灌注成像检测狭窄50%以上冠状动脉的敏感性及特异性分别为:90%和75%;74%和75%。CMR的诊断效能0.879,与SPECT 0.818相似(P=0.3377);基于血管分析,CMR和SPECT负荷心肌灌注成像检测狭窄50%以上冠状动脉的敏感性及特异性分别为:78%和83%;75%和86%。CMR的诊断效能0.827,略好于SPECT 0.767(P=0.1284)。其中基于分支血管进行分析,CMR探测左前降支(LAD)分支血管病变的诊断效能0.849好于SPECT 0.688(P=0.0141)。CMR探测左旋支及右冠状动脉分支血管的诊断效能与SPECT相似,两者间差异无统计学意义。结论:CMR与SPECT负荷心肌灌注成像均能有效检测冠心病心肌缺血,基于患者个体分析,CMR与SPECT相比敏感性高,特异性相同;基于血管分析,CMR的敏感性和特异性均好于SPECT,尤其对于LAD分支血管病变。     

Computerized measurement of magnetic resonance imaging erosion volumes in patients with rheumatoid arthritis: a comparison with existing magnetic resonance imaging scoring systems and standard clinical outcome measures

OBJECTIVE: One of the major aims of therapy in rheumatoid arthritis (RA) is to prevent erosive disease and subsequent disability. One of the important goals of therapy assessment must therefore be the accurate measurement of damage progression. We undertook this study to assess the feasibility, reliability, and validity of measuring magnetic resonance imaging (MRI) erosion volumes and synovial volumes in the wrists of RA patients with the use of a semiautomated computerized method. METHODS: Twelve subjects with seropositive RA were chosen to reflect a spectrum of RA severity as determined by the clinical Joint Alignment and Motion (JAM) Scale. MRI of the dominant wrist was performed at the same time of day at baseline and at 48 hours. Images were transferred to a workstation. Erosion volumes and synovial volumes were measured on the coronal images using OSIRIS imaging software. All images were reread in random order at 72 hours by 1 observer. The results were compared with erosion scores and global synovitis scores obtained by the same observer using the Outcome Measures in Rheumatology Clinical Trials MRI RA scoring system. Radiographs were performed at baseline and were read on 2 occasions by 1 observer using the Scott modification of the Larsen method. RESULTS: Total erosion volume per subject ranged from 0 cm(3) to 4.7 cm(3). The total synovial membrane volume per subject ranged from 0.1 mm(3) to 12.1 cm(3). Intraclass correlation coefficients for erosion volumes and synovial volumes demonstrated excellent intraobserver reliability and interoccasion reliability. There was a strong positive correlation between the total erosion volume and the total erosion score. The correlation between the synovial volumes and synovitis score was less favorable (r = 0.53-0.86). Positive correlations were demonstrated between the erosion volumes, the JAM score, and the modified Larsen scores. No significant correlation was demonstrated between the erythrocyte sedimentation rate, C-reactive protein level, swollen joint count, tender joint count, or the Disease Activity Score in 28 swollen and 28 tender joints and the synovial volumes or synovitis scores. CONCLUSION: This study is the first to demonstrate the feasibility, reliability, and validity of computerized MRI erosion volume measurements in the wrists of RA patients. The method will require further evaluation in terms of interobserver reliability, with examination of responsiveness in longitudinal studies, but the method demonstrates excellent interoccasion and intraobserver reliability and compares favorably with existing RA clinical outcome measures. Synovial volume measurements demonstrated good intraobserver reliability and appeared to be more responsive to synovial change over a 48-hour period in this group of patients.     

Cardiovascular magnetic resonance perfusion imaging at 3-tesla for the detection of coronary artery disease: a comparison with 1.5-tesla.

OBJECTIVES: This study was designed to establish the diagnostic accuracy of cardiovascular magnetic resonance (CMR) perfusion imaging at 3-Tesla (T) in suspected coronary artery disease (CAD). BACKGROUND: Myocardial perfusion imaging is considered one of the most compelling applications for CMR at 3-T. The 3-T systems provide increased signal-to-noise ratio and contrast enhancement (compared with 1.5-T), which can potentially improve spatial resolution and image quality. METHODS: Sixty-one patients (age 64 +/- 8 years) referred for elective diagnostic coronary angiography (CA) for investigation of exertional chest pain were studied (before angiogram) with first-pass perfusion CMR at both 1.5- and 3-T and at stress (140 microg/kg/min intravenous adenosine, Adenoscan, Sanofi-Synthelabo, Guildford, United Kingdom) and rest. Four short-axis images were acquired during every heartbeat using a saturation recovery fast-gradient echo sequence and 0.04 mmol/kg Gd-DTPA bolus injection. Quantitative CA served as the reference standard. Perfusion deficits were interpreted visually by 2 blinded observers. We defined CAD angiographically as the presence of > or =1 stenosis of > or =50% diameter in any of the main epicardial coronary arteries or their branches with a diameter of > or =2 mm. RESULTS: The prevalence of CAD was 66%. All perfusion images were found to be visually interpretable for diagnosis. We found that 3-T CMR perfusion imaging provided a higher diagnostic accuracy (90% vs. 82%), sensitivity (98% vs. 90%), specificity (76% vs. 67%), positive predictive value (89% vs. 84%), and negative predictive value (94% vs. 78%) for detection of significant coronary stenoses compared with 1.5-T. The diagnostic performance of 3-T perfusion imaging was significantly greater than that of 1.5-T in identifying both single-vessel disease (area under receiver-operator characteristic [ROC] curve: 0.89 +/- 0.05 vs. 0.70 +/- 0.08; p < 0.05) and multivessel disease (area under ROC curve: 0.95 +/- 0.03 vs. 0.82 +/- 0.06; p < 0.05). There was no difference between field strengths for the overall detection of coronary disease (area under ROC curve: 0.87 +/- 0.05 vs. 0.78 +/- 0.06; p = 0.23). CONCLUSIONS: Our study showed that 3-T CMR perfusion imaging is superior to 1.5-T for prediction of significant single- and multi-vessel coronary disease, and 3-T may become the preferred CMR field strength for myocardial perfusion assessment in clinical practice.     

Quantitative magnetic resonance imaging of articular cartilage in knee osteoarthritis

PURPOSE OF REVIEW: Attempts to evaluate knee cartilage damage and progression seem logical in osteoarthritis research. Magnetic resonance imaging allows for precise visualization of joint structures such as cartilage, bone, synovial tissues, ligaments and menisci, and their pathologic changes. RECENT FINDINGS: Recent advances in magnetic resonance technology have enabled researchers to evaluate cartilage damage and progression over the cross-sectional and longitudinal planes. Although anatomic changes can be seen, for many years the quantification of the cartilage changes has been the real challenge. Quantitative assessment of cartilage morphology using magnetic resonance imaging with fat-suppressed gradient echo sequences and digital postprocessing techniques provides high accuracy and adequate precision for cross-sectional and longitudinal studies in osteoarthritis patients. Recent data on precision, reliability, and sensitivity to change of quantitative parameters of cartilage morphology in osteoarthritis are presented in this review. Longitudinal studies currently available suggest that changes of cartilage volume, potentially as much as 5% per year, occur in osteoarthritis in most knee compartments, exceeding the variability of these measurements. SUMMARY: Magnetic resonance imaging provides reliable and quantitative data on cartilage status throughout all compartments of the knee, and robust acquisition protocols for multicenter trials are now available. Magnetic resonance imaging technology should hopefully reduce the number of patients needed in clinical trials, improve retention of these patients, and reduce the overall costs and the length of clinical trials of treatment response to disease-modifying osteoarthritis drugs.     

Feasibility of tissue magnetic resonance imaging: a pilot study in comparison with tissue Doppler imaging and invasive measurement

OBJECTIVES: This research was intended to determine the feasibility of tissue magnetic resonance (MR) imaging in comparison with tissue Doppler imaging and its potential implications for the estimation of filling pressure, in comparison with invasive measurement. BACKGROUND: Evaluation of diastolic function using MR imaging is commonly confined to the study of transmitral flow. However, transmitral flow is unreliable for the estimation of left ventricular (LV) filling pressures in hypertrophy and normal systolic function. Normalizing early mitral velocity (E) for the influence of myocardial relaxation by combining E with early diastolic mitral septal tissue velocity (Ea) provides better Doppler estimates of filling pressures. METHODS: Eighteen patients with hypertensive heart disease (LV mass index: 114 +/- 21 g/m(2)), absence of valvular regurgitation, and with normal or mildly reduced systolic function (LV ejection fraction: 57.6 +/- 6.5%) referred for cardiac catheterization, underwent consecutive measurement of mitral flow and septal tissue velocities with phase-contrast MR and Doppler. These data were compared with mean pulmonary capillary wedge pressure (PCWP). RESULTS: There was a strong relation between MR (11.6 +/- 4.3) and Doppler-assessed (12.1 +/- 3.5) E/Ea (95% confidence interval of -1.5 to 0.5) (r = 0.89, p < 0.0001). In addition, E/Ea related strongly to invasively measured PCWP (MR: r = 0.80, p < 0.0001 and Doppler: r = 0.85, p < 0.0001). CONCLUSIONS: Tissue MR imaging is a feasible method to assess Ea. Combining E and Ea allowed similar estimation of filling pressure by MR and Doppler, in good agreement with invasive measurement. The potential confounding effect of valvular regurgitation needs further study.     

Pulmonary embolism: comparison of angiography with spiral computed tomography,magnetic resonance angiography,and real-time magnetic resonance imaging

In the last decade, spiral computed tomography (CT) and magnetic resonance (MR) angiography (MRA) have become a viable alternative to conventional angiography in the diagnosis of acute pulmonary embolism. However, patients with dyspnea are often unable to hold their breath for a longer time and thus image degradation is frequently observed. Consequently, an imaging sequence that allows free breathing is desirable. The aim of this animal study was to compare contrast-enhanced spiral CT, MRA and a real-time MR sequence, the latter without breath-hold, with pulmonary angiography as reference gold standard. Nine pigs with artificially induced pulmonary embolism underwent this multimodality comparison. All images were independently evaluated for the presence of pulmonary emboli by two reviewers. Forty-three filling defects were detected by conventional angiography on lobar and segmental levels. Sensitivity of CT images was 72.1 and 69.8% for Readers 1 and 2, respectively, and sensitivity of MRA images was 79.1 and 81.4%. With real-time MR imaging, however, the detection rate was 97.7% for both readers. We conclude that, under experimental conditions, real-time MR imaging without the use of radiation or iodinated contrast material is comparable with angiography in the detection of pulmonary emboli.