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Objective: The aim of this study was to investigate the prevalence of TMJ chondrocalcinosis on head CT scans in patients with chondrocalcinosis of the knee or wrist. Methods and materials: 227 patients with radiological evidence of calcifications on knee or wrist radiographs had a head CT scan obtained for unrelated purposes. CT scans were retrospectively reviewed for the presence of temporomandibular crystal deposition. Prevalence, bilaterality, age and gender distribution were determined. Results: 41 of 227 (18%) of patients had TMJ chondrocalcinosis. TMJ chondrocalcinosis was more common in females (17%) than males (1%). It was more commonly unilateral (68%) than bilateral (32%). Conclusion: In patients with peripheral calcific disease, the TMJ is more commonly involved than previously reported and this is more common in females compared to males.

Learning objectives Background Imaging findings OR procedure details Conclusion References Personal Information, Learning objectives: To illustrate the health effects of electronic...

The use of hyaluronic acid nanoshells has been proposed to encapsulate prodrugs and exploit the mechanisms of interactions between living cells, like endocytes or cancer cells and hyaluronic acid, which is a natural component of the extracellular matrix. In this review we describe the potential and the limits of this promising research trend and discuss the theoretical advantages of such an engineering approach. Is it a possible scalability to increase the efficacy and biodegradability of molecules like contrast media and radiotracers especially for neuroradiology and nuclear medicine studies.

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: The purpose of this study is to assess fluid in the tendon sheaths on MRI imaging in healthy...

Recently, we published a first anatomical Diffusion Tensor Imaging (DTI) atlas regarding white matter tracts in the canine brain. The purpose of this study was to show the significance of DTI in the revelation of the white matter fibres in the feline brain (i.e. to obtain an anatomical DTI atlas of images) and to descriptively compare these to previously obtained white matter fibre images of the canine brain. DTI MR Images of 4 cats euthanised for reasons other than neurological disorders were obtained with a 3 T system. Combined fractional anisotropic (FA) and directional maps were obtained within the hour after death. An experienced anatomist tracked white matter tracts of clinical relevance using the scanner software. After validation of these tracts, we compared relevant neurological connections between the cat and the dog. Comparison of cerebral structures between different species is easier when the three dimensional anatomy is visualized by using DTI. 3D rendered DTI images clearly show major differences in neurological architecture between cats and dogs e.g. the more important space occupying role of the limbic system, and the less diffuse, less nodular, less pronounced and thinner fibre bundles in the feline brain compared to the canine brain (except for the cerebellum different parts connecting fibres passing through the brainstem which are pronouncedly developed). This article is protected by copyright. All rights reserved.

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Micro-computed tomography (micro-CT) is accepted as a non-invasive research tool to monitor tumor growth in small animal imaging studies. Serial micro-CT imaging allows longitudinal investigation of the same animal. Radiation exposure is a potential...

This abstract presents a novel classification approach for microcalcifications extracted from core biopsy tissue samples digitized using microCT. Because of lack of ground truth, it is investigated whether the application of a clustering method as a preprocessing step before classification would improve the obtained classification results.

Aims and objectives Methods and materials Results Conclusion Personal information References, Aims and objectives: Advanced imaging methods can play an increasing role in preclinical studies. Microcomputed tomography (Micro-CT)offers excellent resolution, but has been restricted to the analysis of x-ray attenuating tissues like bone. The soft tissue contrast...

Learning objectives Background Imaging findings OR Procedure details Conclusion References Personal Information, Learning objectives: To illustrate the radiological findings in pulmonary alveolar microlithiasis...

Purpose: To assess the impact of combining low-tube voltages and iterative reconstruction (IR) on contrast dose in coronary CTA. Methods and Materials: A standard of care (SoC) 120kVp scan with 320mgI/ml iodine based contrast (Visipaque, GE Healthcare) and FBP reconstruction was compared with two study protocols: 80kVp with 160mgI/ml (protocol A) and 100kVp with 200mgI/ml (protocol B), both reconstructed with IR (ASiR). Each protocol was scanned (Discovery) three times on two minipigs (Ellegaard) with constant injection protocol (speed 3ml/s, volume 1.5ml/kg) and radiation dose. Quantitative image quality was evaluated by CT-value and signal-to-noise ratio (SNR) of the right coronary artery (RCA), left anterior descending coronary (LAD) and left circumflex artery (LCx). Expert readers performed qualitative assessment for overall quality, vessel sharpness, noise and streak artifacts. Results: Despite reduced iodine load, both study protocols did not yield inferior CT-value and SNR for all arteries. For RCA, the mean SoC signal (307HU) was preserved with protocol A (273HU, p=0.15) and B (258HU, p=0.08). Also the SNR was non inferior from SoC (SNR=7.0) with A (8.1, p=0.75) and B (8.7, p=0.57). All scans were perceived to be of at least acceptable quality on all evaluated parameters allowing diagnostic interpretation. No statistical differences were observed (all p-values>0.12), except for streak artifacts (p=0.01) who were considered to be more severe, although acceptable, with protocol A. Conclusion: The use of a reduced tube voltage combined with iterative reconstruction allows a marked reduction in iodine dose up to a factor of two without impairing image quality.

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Purpose To assess the impact of contrast media concentration on the height and length of arterial enhancement at constant iodine dose delivery rate (IDR) and total iodine dose (TID). Methods and Materials Four minipigs (Ellegaard, Denmark) received a total of 56 dynamic cine scans (length 120s, frequency 2 images per s) in a 4cm segment at hepatic level to obtain high temporal-resolution enhancement curves in the abdominal aorta (CT-750 HD, GE Healthcare, 120kVp, 300mA). Seven iodine based contrast concentrations (370, 320, 300, 270, 200, 160, and 120 mg I/ml) obtained by dilution were administered through a port-a-cath unit, injection pressure (psi) was recorded from the power injector (Nemoto, Japan). Both injection speed and volume were adapted to maintain constant IDR (0.64 g I/s) and TID (320 mg I/kg). Figures of merit for arterial enhancement were maximum CT value (CTmax) and the temporal window in which the CT value remained above 200HU (?t>200HU). Results Iodine concentration had a significant effect: the injection of lower concentrations at higher speed was associated with increased enhancement (Figure). Compared to 370 mg I/ml, all concentrations equal and below to 270 mg I/ml resulted in both a broader and higher arterial peak (all p-values200HU increased from 7.3s at 370 mg I/ml up to 15.8s at 120 mg I/ml, whereas CTmax increased from 237 HU to 271 HU, respectively. Despite higher injection speed, only a marginal increase in injection pressure was observed for lower iodine concentrations due to their reduced viscosity. Conclusion Despite constant IDR and TID, injecting a reduced contrast media concentration at higher speed results in a higher arterial peak enhancement and improved time window above 200 HU compared to the administration of a high contrast media concentration at lower speed. Clinical relevance Reduced iodine concentration potentially improves image quality and relaxes the timing of the acquisition in CT angiography studies at equal iodine burden. Alternatively, the increased enhancement at lower iodine concentrations allows the reduction of total iodine dose to the patient without impairing image quality.

Purpose To evaluate image quality of a study protocol with reduced iodine dose and a combination of low tube voltage CT acquisition and iterative reconstruction (IR). Materials Two minipigs were scanned to compare a study protocol with low tube voltage - low iodine concentration (100kVp, 200mgI/ml) and iterative reconstruction (ASiR-60%) towards a standard of care protocol (120kVp, 320mgI/ml) with filtered back-projection. All scans were performed with constant injection protocol (speed 3ml/s, volume 1.5ml/kg, scan delay 30s) and equal radiation dose. CT-value and signal-to-noise-ratio (SNR) were measured in the right coronary artery (RCA), left anterior descending coronary (LAD) and left circumflex artery (LCx). Two expert readers scored overall image quality, vessel sharpness, image noise and artifacts on a five point scale. Statistics were performed by Mann-Whitney U test and Chi-square analysis. Results The study protocol did not result in inferior CT-signal and SNR. The standard RCA signal (307 ± 48 HU) was not significant different (p = 0.15) from the study protocol (258 ± 31 HU). Similar results were observed for SNR (p = 0.57), with comparable results between the standard (SNR 7.0 ± 2.5) and study protocol (SNR 8.7 ± 2.5). Expert reading confirmed these findings, showing no difference (all p-values > 0.12) between the standard (average score 4.2) and the study protocol (average score 3.9) for all evaluated parameters. All images were considered to be of at least acceptable diagnostic quality. Conclusion The combined use of reduced tube voltage with iterative reconstruction allows a marked reduction in total iodine dose without impairing image quality.

Diffusion weighted imaging sequences are now widely available on Magnetic Resonance Imaging (MRI) scanners. Diffusion Tensor Imaging (DTI) of the brain is able to show white matter tracts and is now commonly used in human medicine to study brain anatomy, tumors, structural pathways,... The purpose of this study was to show the interest of DTI to reveal the white matter fibers in the dogs' brain. DTI MR Images for this study were obtained with a 3 T system of 4 dogs euthanized for other reasons than neurological disorders. Combined fractional anisotropic (FA) and directional maps were obtained in the first 2 hours after death. The heads were amputated immediately after scanning and stored in 10% formalin until preparation for dissection. An experienced anatomist tracked white matter tracts with clinical relevance using the scanner software. The selected tracts were REFVIDume rendered and correlated with gross dissection. Using DTI we were able to track relevant neurological connections, such as the corticospinal tract, the optic and the cerebellar tract. The three dimensional anatomy is better presented using modern visualization techniques. DTI seems to be a valuable tool in order to present clinically relevant white matter tracts to neurological clinicians and researchers.

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Purpose: Dual energy CT is a technique that increases CT value accuracy by reducing spectral artifacts [1], and allows the reconstruction of synthesized monochromatic images at several selectable energies. By selecting an image at low keV range, the contrast between tissues is enhanced, which could allow a reduction of contrast agent volume. However, this involves an increase of the noise levels due to the lower photon flux associated with such low energy. The latter may be tackled by additional iterative reconstruction which reduces noise. The purpose of this study is to assess the potential of two versions of DECT (one without and one with iterative reconstruction) to enhance image quality (IQ) in iodine contrast studies. The study is performed on a phantom and on a porcine model: Phantom: * assessment of the accuracy of the DECT CT values and iodine concentration estimated by DECT * comparison of IQ obtained by DECT with the standard of care IQ, and impact of iterative reconstruction on the DECT IQ. Porcine model: * verification of the phantom results Methods and materials: Section: Methods and Materials Sidebar Fig. 1: Water phantom with two times 10 tubes with well known iodine concentrations...Ten tubes with iodine contrast (Visipaque 320, GE Healthcare) concentrations (1-10 mgI/ml) were inserted in a water phantom. The phantom was scanned on a HD750 CT scanner (GE Healthcare) with standard of care (SoC) 120kVp and with DECT (without and with iterative reconstruction, respectively referred to by GSI v1 and GSI v2)) at equal radiation dose (CTDIvol 12.9 mGy). The linearity and accuracy of the iodine concentration estimation was assessed. Furthermore, the quality of the monochromatic series was evaluated by assessing the CNRD as a function of monochromatic keV selection. The results are compared to the SoC scan. For the porcine model, an adult minipig (Ellegaarden) (38kg, diameter similar to human adults) was scanned with following scan protocols:1.Standard of Care scan: 120kV scan in arterial phase after administration of 320 mgI/ml concentration contrast agent (CTDIvol 10.5 mGy) 2.DECT scan )v2) in arterial phase after administration of saline diluted contrast agent with concentration 160mgI/ml (CTDIvol 15.02 mGy) 3.DECT v2scan in arterial phase after administration of saline diluted contrast agent with concentration 220mgI/m (CTDIvol 15.02 mGy) 4.DECT v2scan in arterial phase after administration of saline diluted contrast agent with concentration 320mgI/ml (CTDIvol 15.02 mGy) Contrast agent was administered at a rate of 2ml/s and volume 2ml/kg. CT values and noise were measured in aorta and dorsal muscle and CNRD was computed. Results: 1. Phantom study a) Accuracy of the iodine concentration estimated by DECT Similar to standard CT, the CT value in the DECT scan of the phantom increases linearly with iodine concentration for the various monochromatic energies in the range 40-140 keV as shown in figure 2. Inaddition, the DECT estimated iodine concentrations correspond well with the real iodine concentration (see figure 3). A repeated scan with a different protocol (higher dose) shows that a bias up to 1 mgI/ml may occur. b) CNRD as function of energy Both GSI v1 and GSI v2 DECT scans of the phantom showed an improved CNRD compared to the SoC scan for all iodine concentrations as is shown in figure 4. The peak DECT CNRD is around 130% of the SoC CNRD and does not vary for different concentrations. Without advanced noise suppression (GSI v1), a maximum CNRD peak was observed at 68 keV with a rapid drop at lower energies due to the domination of noise. By using iterative noise correction (GSI v2), the CNRD remains preserved in a larger energy window (40 - 80 keV). 2. Porcine study The CNRD curves in the porcine study show a similar trend compared to the CNRD curves in the phantom study. A monochromatic energy level can be found which maximizes the CNRD, and this level (50 to 55 keV) is similar for the repeated scans with different administered iodine fluxes. At this energy level, the CNRD corresponding to the 320 mgI/ml DECT scan is more than 100% larger than the SoC CNRD. From figure 5, 160mgI/ml appears to be sufficient to preserve CNRD in the range of 40 to 70 kV. Since the iodine CT value in aorta is improved in the range 40 - 55 keV (figure 6), and the soft tissue noise in a range from 50 to 140 keV (figure 7), there is a small energy window (50-55 keV) in which 160 mgI/ml scan preserves the CNRD without compromising on image quality. This energy window becomes larger in case higher iodine concentrations are used. Conclusion: The results illustrate the linearity of DECT CT value w.r.t. the iodine concentration in the phantom, and the accuracy of the iodine concentration estimated by DECT. Furthermore, the results on the phantom and porcine model show that the use of iterative reconstruction in DECT monochromatic energy images enlarges the window in the lower monochromatic energy range in which the CNRD is improved compared to a SoC scan. The high peak CNRD's obtained by DECT indicate the potential of a significant reduction of the administered iodine flux without impairing image quality.