Cyrus Behzadi

Perspectives on the revised Ghent criteria for the diagnosis of Marfan syndrome

Three international nosologies have been proposed for the diagnosis of Marfan syndrome (MFS): the Berlin nosology in 1988; the Ghent nosology in 1996 (Ghent-1); and the revised Ghent nosology in 2010 (Ghent-2). We reviewed the literature and discussed the challenges and concepts of diagnosing MFS in adults. Ghent-1 proposed more stringent clinical criteria, which led to the confirmation of MFS in only 32%–53% of patients formerly diagnosed with MFS according to the Berlin nosology. Conversely, both the Ghent-1 and Ghent-2 nosologies diagnosed MFS, and both yielded similar frequencies of MFS in persons with a causative FBN1 mutation (90% for Ghent-1 versus 92% for Ghent-2) and in persons not having a causative FBN1 mutation (15% versus 13%). Quality criteria for diagnostic methods include objectivity, reliability, and validity. However, the nosology-based diagnosis of MFS lacks a diagnostic reference standard and, hence, quality criteria such as sensitivity, specificity, or accuracy cannot be assessed. Medical utility of diagnosis implies congruency with the historical criteria of MFS, as well as with information about the etiology, pathogenesis, diagnostic triggers, prognostic triggers, and potential complications of MFS. In addition, social and psychological utilities of diagnostic criteria include acceptance by patients, patient organizations, clinicians and scientists, practicability, costs, and the reduction of anxiety. Since the utility of a diagnosis or exclusion of MFS is context-dependent, prioritization of utilities is a strategic decision in the process of nosology development. Screening tests for MFS should be used to identify persons with MFS. To confirm the diagnosis of MFS, Ghent-1 and Ghent-2 perform similarly, but Ghent-2 is easier to use. To maximize the utility of the diagnostic criteria of MFS, a fair and transparent process of nosology development is essential.

High incidence of osteochondral lesions after open reduction and internal fixation of displaced ankle fractures: Medium-term follow-up of 100 cases.

BACKGROUND The incidence of osteochondral lesions (OCLs) in association with displaced ankle fractures has only been examined in two previous studies. In both studies magnetic resonance imaging (MRI) was performed prior to open reduction and internal fixation (ORIF). Because MRI may overdiagnose or overestimate the extent of OCLs in an acute trauma setting the aim of this study was to determine the incidence of OCLs after ORIF of displaced ankle fractures using MRI at medium-term follow-up, and to analyse if the severity of fracture or the clinical outcome correlates with the incidence of OCLs. PATIENTS AND METHODS Following institutional review board approval a total of 100 patients (mean age, 41.3 years; range, 17.9-64.3 years) with a displaced ankle fracture who had undergone ORIF according to the AO principles were included in this study. The American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score was used to quantify the clinical outcome and MR images were evaluated for OCLs of the talus and distal tibia after a mean of 34.5 months (range, 17.5-54.1 months). RESULTS OCLs were found in 40.4% of the patients. Logistic regression revealed a significant correlation between the severity of fracture and the incidence of OCLs. Patients with a trimalleolar fracture (p=0.04) or an ankle fracture dislocation (p=0.003) had a significantly higher risk for developing an OCL compared to those with a type B fracture. Logistic regression also demonstrated a significant correlation between the clinical outcome (AOFAS score) and the incidence of OCLs (p=0.01). The risk for developing an OCL increases up to 5.6% when the AOFAS score decreases by one point. CONCLUSION OCLs were frequently found in association with acute ankle fractures at medium-term follow-up, and the severity of fracture was associated with an increased number of OCLs. Considering the disadvantages of MRI including the high cost and limited availability, the results of this study may help to explain why anatomic surgical realignment of displaced ankle fractures may still be associated with poor clinical outcomes.

Comparison of conventional radiography and MDCT in suspected scaphoid fractures

AIM To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography (MDCT) in suspected scaphoid fractures. METHODS One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities. RESULTS Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients (42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT (P < 0.01) concerning scaphoid fracture detection. The mean effective dose of MDCT was 0.1 mSv compared to 0.002 mSv of conventional radiography. CONCLUSION Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma.

CT Pulmonary Angiography at Reduced Radiation Exposure and Contrast Material Volume Using Iterative Model Reconstruction and iDose4 Technique in Comparison to FBP

Purpose To assess image quality of CT pulmonary angiography (CTPA) at reduced radiation exposure (RD-CTPA) and contrast medium (CM) volume using two different iterative reconstruction (IR) algorithms (iDose4 and iterative model reconstruction (IMR)) in comparison to filtered back projection (FBP). Materials and Methods 52 patients (body weight < 100 kg, mean BMI: 23.9) with suspected pulmonary embolism (PE) underwent RD-CTPA (tube voltage: 80 kV; mean CTDIvol: 1.9 mGy) using 40 ml CM. Data were reconstructed using FBP and two different IR algorithms (iDose4 and IMR). Subjective and objective image quality and conspicuity of PE were assessed in central, segmental, and subsegmental arteries. Results Noise reduction of 55% was achieved with iDose4 and of 85% with IMR compared to FBP. Contrast-to-noise ratio significantly increased with iDose4 and IMR compared to FBP (p<0.05). Subjective image quality was rated significantly higher at IMR reconstructions in comparison to iDose4 and FBP. Conspicuity of central and segmental PE significantly improved with the use of IMR. In subsegmental arteries, iDose4 was superior to IMR. Conclusions CTPA at reduced radiation exposure and contrast medium volume is feasible with the use of IMR, which provides improved image quality and conspicuity of pulmonary embolism in central and segmental arteries.

Comparison of image quality and visibility of normal and abnormal findings at submillisievert chest CT using filtered back projection, iterative model reconstruction (IMR) and iDose(4)™.

OBJECTIVE To compare both image quality and visibility of normal and abnormal findings at submillisievert chest CT (smSv-CT) using filtered back projection (FBP) and the two different iterative reconstruction (IR) techniques iterative model reconstruction (IMR) and iDose4™. MATERIALS AND METHODS This institutional review board approved study was based on retrospective interpretation of clinically indicated acquired data. The requirement to obtain informed consent was waived. 81 patients with suspected pneumonia underwent smSv-CT (Brilliance iCT, Philips Healthcare; mean effective dose: 0.86±0.2mSv). Data were reconstructed using FBP and two different IR techniques iDose4™ and IMR (Philips Healthcare) at various iteration levels. Objective image noise (OIN) was measured. Two experienced readers independently assessed all images for image noise, image appearance and visibility of normal anatomic and abnormal findings. A random intercept model was used for statistical analysis. RESULTS Compared to FBP and iDose4™, IMR reduced OIN up to 88% and 72%, respectively (p<0.001). A mild blotchy image appearance was seen in IMR images, affecting diagnostic confidence. iDose4™ images provided satisfactory to good image quality for visibility of normal and abnormal findings and were superior to FBP (p<0.001). IMR images were significantly inferior for visibility of normal structures compared to iDose4™, while being superior for visibility of abnormal findings except for reticular pattern (p<0.001). CONCLUSION IMR results for visibility of normal and abnormal lung findings are heterogeneous, indicating that IMR may not represent a priority technique for clinical routine. iDose4™ represents a suitable method for evaluation of lung tissue at submillisievert chest CT.

Quantitative T2* relaxation time analysis of articular cartilage of the tibiotalar joint in professional football players and healthy volunteers at 3T MRI

To compare T2* relaxation times of the tibiotalar cartilage between professional football players and matched healthy male volunteers.

Intraindividual comparison of image quality using retrospective and prospective respiratory gating for the acquisition of thin sliced four dimensional multidetector CT of the thorax in a porcine model.

ABSTRACT Purpose: To intraindividually compare image quality and anatomical depiction of the lung and mediastinum using retrospective and prospective respiratory gating techniques for the acquisition of 4D-multidetector computed tomography (MDCT) of the chest in a porcine model. Materials and Methods: Twelve trachealy intubated domestic pigs underwent 64-row MDCT of the thorax. For retrospective and prospective gating the automated respiratory frequency was adjusted to 10, 14, 18, and 22 respiratory cycles per minute. Further, free breathing MDCT scans of the lung were performed at the same respiratory settings. A breathhold scan was acquired which served as the reference standard. Three reviewers independently analyzed the MDCT data applying a 4-point-grading scale regarding the degree of artifacts observed and anatomical depiction (1, excellent, no artifacts; 4, nondiagnostic due to severe artifacts). For statistical analysis the Wilcoxon matched pairs and Chi-square test were used. Results: Breathhold imaging allowed for the highest image quality (mean value: trachea, 1.00; bronchi, 1.10; lung parenchyma, 1.08; diaphragm, 1.00; pericardium, 1.80). Retrospective gating proved to be of superior image quality compared to prospective gating for all respiratory frequencies. With the respiratory frequency set to 14/min retrospective gating even enabled an identical image quality score as at breathhold. Performing image acquisition during continuous breathing lead to a severe decrease in image quality. Conclusions: High image quality can be acquired using respiratory gating techniques for 4D-MDCT of the thorax. Retrospective is superior to prospective gating and can be of an equivalent image quality as standard breathhold imaging, but at the cost of a significantly higher radiation dose.

Comparison of T2* relaxation times of articular cartilage of the knee in elite professional football players and age-and BMI-matched amateur athletes

OBJECTIVE Recent investigation has underlined the potential of quantitative MR imaging to be used as a complementary tool for the diagnosis of cartilage degeneration at an early state. The presented study analyses T2* relaxation times of articular cartilage of the knee in professional athletes and compares the results to age- and BMI (Body Mass Index)-matched healthy amateur athletes. MATERIALS AND METHODS 22 professional football players and 22 age- and BMI-matched individuals were underwent knee Magnetic Resonance Imaging (MRI) at 3T including qualitative and quantitative analysis. Qualitative analysis included e.g. meniscal tears, joint effusion and bone edema. For quantitative analysis T2* (22 ET: 4.6-53.6ms) measurements in 3D data acquisition were performed. Deep and superficial layers of 22 predefined cartilage segments were analysed. All data sets were postprocessed using a dedicated software tool. Statistical analysis included Student t-test, confidence intervals and a random effects model. RESULTS In both groups, T2* relaxation times were significantly higher in the superficial compared to the deep layers (p<0.001). Professional athletes had significantly higher relaxation times in eight superficial and three deep cartilage layers in the predefined cartilage segments (p<0.05). Highly significant differences were found in the weight-bearing segments of the lateral superficial femoral condyle (p<0.001). CONCLUSION Elevated T2* values in cartilage layers of professional football players compared to amateur athletes were noted. The effects seem to predominate in superficial cartilage layers.

Inter- and Intraobserver reproducibility of T2 relaxation times of the discus interpubicus: A feasibility study at 3 Tesla

Objective To quantify standard values of the discus interpubicus in healthy subjects and to determine reliability and repeatability using T2 relaxation time measurements at 3T. Methods 20 asymptomatic participants (10 male, 10 female; mean age: 27.3 years ±4.1, BMI: 22.2 ±1.8) underwent a 3T Magnetic Resonance Imaging (MRI) of the pelvic region in a supine position. We included sagittal and para-axial T2w sequences centred over the pubic symphysis in order to identify the complete discus interpubicus. For quantitative analysis, a multi-echo Turbo Spin Echo (TSE) sequence (including 12 echo times between 6.4 and 76.8 ms) was acquired and analysed by using an in-house developed quantification plugin tool (qMapIt) extending ImageJ. Two readers in consensus defined three central slices of the pubic symphysis with the greatest length. For each slice, both readers separately placed three regions-of-interest (ROI) covering the whole discus interpubicus. Both readers repeated the ROI placements in identical fashion after a four-week interval on the original MRI images. Statistical analysis included intraclass correlation coefficient (ICC), nonparametric Wilcoxon test, Fisher exact test and mean relaxation time in ms and 95% confidence intervals. Results T2 relaxation time analysis was performed for all 20 participants. In total, a mean relaxation time of all analysed segments for both observers was 48.6 (±6.3 ms), with a mean relaxation time for observer 1 of 48.7 (±6.0 ms) and for observer 2 of 48.5 ms (±6.6ms). The calculated ICC comparing inter- and intrarater reproducibility was excellent in all segments (≥0.75). Conclusion T2 mapping of the discus interpubicus demonstrates good inter- and intrarater repeatability as well as reliability. Mean relaxation times were calculated with 48.6ms in healthy volunteers.

T2 relaxation times of the anterolateral femoral cartilage in patients after ACL-reconstruction with and without a deep lateral femoral notch sign

PURPOSE To quantitatively assess T2 relaxation times of the anterolateral femoral cartilage following anterior cruciate ligament (ACL)-reconstruction with and without a positive deep lateral femoral notch sign (DLNS) at post-traumatic MRI. MATERIALS AND METHODS In 52 patients post-traumatic MRI as well as 12 months after ACL-rupture (ACLR) and surgical treatment were analysed. In 28 patients a positive DLNS was present at post-traumatic MRI. For quantitative analysis, T2 relaxation time measurements (7 TE: 10-70 ms) were performed at time of re-evaluation. Three polygonal ROIs encompassing the full cartilage layer were placed in the anterolateral femoral cartilage. Clinical assessment included Lysholm-Tegner-Activity-Score, Rasmussens clinical score and modified Cincinnati-Rating-System-Questionnaire. Description and differences were calculated as means and confidence intervals of means, controlled for the cluster effect of person, if appropriate. RESULTS In patients with a positive DLNS after ACLR, relaxation times in the notch region were significantly prolonged compared to patients without a positive DLNS (Δ 7.4 ms, CI: 5.6-9.2; p-value <0.001) as well as to the adjacent anterior (Δ 5.7 ms, CI: 4.7-6.7; p-value <0.001) and central femoral cartilage (Δ 6.6 ms, CI: 5.7-7.6; p-value <0.001). Solely insignificant differences were noticed in the performed clinical scores comparing the two groups (p > 0.05). CONCLUSION Significantly prolonged T2 relaxation times of the anterolateral femoral cartilage were found in patients with a positive DLNS following ACL-reconstruction compared to patients without a DLNS. Based on these results, it has to be assumed that a positive DLNS is associated with higher cartilage degradation.