MRI T2 Mapping of Knee Articular Cartilage Using Different Acquisition Sequences and Calculation Methods at 1.5 Tesla.

OBJECTIVE: This study aims to determine how magnetic resonance imaging (MRI) acquisition techniques and calculation methods affect T2 values of knee cartilage at 1.5 tesla and to identify sequences that can be used for high-resolution T2 mapping in short scanning times. MATERIALS AND METHODS: This study was performed on phantom and 29 patients who underwent MRI of the knee joint at 1.5 tesla. The protocol includes T2 mapping sequences based on Single-Echo Spin Echo (SESE), Multi-Echo Spin Echo (MESE), Fast Spin Echo (FSE) and Turbo Gradient Spin Echo (TGSE). The T2 relaxation times were quantified and evaluated using three calculation methods (MapIt, Syngo Offline and mono-exponential fit). signal-to-noise ratios (SNR) were measured in all sequences. All statistical analyses were performed using the t-test. RESULTS: The average T2 values in phantom were 41.7 ± 13.8 ms for SESE, 43.2 ± 14.4 ms for MESE, 42.4 ± 14.1 ms for FSE and 44 ± 14.5 ms for TGSE. In the patient study, the mean differences were 6.5 ± 8.2 ms, 7.8 ± 7.6 ms and 8.4 ± 14.2 ms for MESE, FSE and TGSE compared to SESE, respectively; these statistical results were not significantly different (p > 0.05). The comparison between the three calculation methods showed no significant difference (p > 0.05). The t-test showed no significant difference between SNR values for all sequences. CONCLUSION: T2 values depend not only on the sequence type but also on the calculation method. None of the sequences revealed significant differences compared to the SESE reference sequence. TGSE with its short scanning time can be used for high-resolution T2 mapping.

Prevention of central venous line-related thrombosis by continuous infusion of low-dose unfractionated heparin, in patients with haemato-oncological disease. A randomized controlled trial.

We have conducted a prospective randomized controlled trial to evaluate the role of low-dose unfractionated heparin prophylaxis in preventing central venous line-related thrombosis in patients with haemato-oncological disease. Patients were randomly assigned to receive either prophylactic intravenous unfractionated heparin (continuous infusion of 100 IU/kg/daily) or 50 ml/daily of normal saline solution as a continuous infusion. CVLs were externalized, non tunneled, double lumen catheters. All CVLs were placed percutaneously by the same physician in the subclavian vein. Upper limb veins were systematically examined by ultrasonography just before, or <24 hours after, catheter removal, and in case of clinical signs of thrombosis. One hundred and twenty-eight CVLs were inserted. Catheter-related thrombosis occurred in 1.5% of the catheters inserted in patients of the heparin group, and in 12.6% in the control group (p = 0.03). No other risk factors were found for the development of catheter-related thrombosis. Two and three patients experienced severe bleeding in the heparin group, and in the control group, respectively (p = 0.18). There were no other side-effects clearly ascribable to the use of unfractionated heparin. This is the first prospective, randomized study, which shows that low-dose of unfractionated heparin is safe and effective to prevent catheter-related thrombosis in patients with haemato-oncological disease.

[Value of imaging in the diagnosis of peripheral neurofibrosarcomas: a case report]. / Apport de l'imagerie dans le diagnostic des neurofibrosarcomes périphériques: à propos d'un cas.

Neurofibrosarcoma is a rare malignant peripheral nerve sheath tumour. It's the consequence of degeneration of neurofibroma in patients with neurofibromatosis. In the absence of clinical symptoms of malignancy, imaging is of prime importance. The observed new case of cubital neurofibrosarcoma stimulated the researchers to give more importance to MR imaging in distinguishing from the benign tumors.

[Results and indications of imaging techniques in musculoskeletal diseases]. / Apport et indications des techniques d'imagerie dans la pathologie de l'appareil locomoteur.

Imaging is necessary in the diagnosis of musculoskeletal diseases and X rays is the first step of this morphological exploration. Ultrasonography is cost effectiveness, without radiation and have to constitute the second step of the exploration of the smooth tissue (tendon, muscle, sheath, synovium and superficial ligaments). Computed tomography with its new technological progress is very effective in the study of the cortical bone. Magnetic resonance imaging, a non irradiating but costly technique, becomes inevitable in several osteo-articular affections. It often makes the examination of last intention to compensate for the inadequacy of ultrasonography and computed tomography.