Interventional spine procedures.

Minimally invasive techniques for the treatment of some spinal diseases are percutaneous treatments, proposed before classic surgery. By using imaging guidance, one can significantly increase accuracy and decrease complication rates. This review report physiopathology and discusses indications, methods, complications and results of performing these techniques on the spine, including different level (cervical, thoracic, lumbar and sacroiliac) and different kind of treatments (nerve block, disc treatment and bone treatment). Finally the present article also reviews current literature on the controversial issues involved.

Radiation dose in vertebroplasty.

We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements.

Diffusion-weighted MRI in cortical ischaemia.

We carried out MRI on 16 male and three female comatose patients, aged 2 days to 79 years, with suspected cortical ischaemia referred from our intensive care units. Using a head coil, and following standard imaging, including coronal fluid-attenuated inversion-recovery images, we performed diffusion-weighted imaging (DWI) using a whole-brain multislice single-shot echo-planar sequence with b 0 and 1000 s/mm2: 5-mm slices covering the whole brain, TR 7000 TE 106 ms, 128 x 128 pixels, field of view 250 mm, one excitation. Maps of apparent diffusion coefficients (ADC) were generated automatically. DWI showed cortical, basal ganglia and watershed-area high signal in all cases, associated with a decrease in ADC to 60- 80% of normal. DWI showed lesions not seen (40%) or underestimated (40%) on conventional T2-weighted imaging. Within 24 h of the onset of symptoms, DWI showed changes not readily detectable on T2-weighted images. The cortical high signal on DWI and the ADC changes, suggesting severe ischaemia rather than oedema, was found in areas known to be affected by cortical laminar necrosis. Extension to the brain stem and white matter was associated with a higher likelihood of death.

Diffusion weighted MR imaging on a low-field open magnet. Comparison with findings at 1.5T in 18 patients with cerebral ischemia.

Diffusion-weighted MR imaging (DWI) is particularly sensitive for the detection of acute stoke. Until recently, DWI was performed with EPI technology. We compared 18 patients with clinical suspicion of acute stroke on a standard 1.5T unit and an open low-field MR scanner. Eighteen patients with 20 lesions of acute stroke were studied retrospectively with DWI and ADC mapping on both systems. The technique used was a rotating fast-spin echo T2 at low-field and an EPI sequence at 1.5T. Both examinations were performed within 24 hours and analyzed by two neuroradiologists. We obtained the same results on DWI sequences on both systems, regarding high intensity lesions on DWI. Interpretation of the ADC maps proved to be difficult on low-field MR near the lateral ventricles (3/18). We experienced the same difficulty of interpretation at low and high field in the cerebellum, in the temporal fossa and in cortex situated near bone, due to susceptibility artifacts. Chronic lesions were better visualized at low than at high field. In our opinion, DWI on a low-field open MR scanner is a good technique to evaluate subacute stroke and was as reliable as when performed on a 1.5T MR system.

[Duplex ultrasonography in the diagnosis of deep vein thrombosis of the legs. Agreement between two operators]. / L'écho-Doppler dans le diagnostic de thrombose veineuse profonde des membres inférieurs. Accord entre 2 opérateurs.

The operator-dependent nature of venous Duplex-ultrasonography diagnosis of deep venous thrombosis (DVT) of the leg is the principal reproach applied to it and a reason for delaying use. The aim of the present study was to evaluate concordance between two operators, with rigorous application of the same methodology of exploration of the venous axes. The study included 82 patients under hospital care, randomly selected from among those referred for the first Duplex-ultrasonography examination for DVT, and having accepted to undergo 2 consecutive explorations, one by each of the two operators. The two operators evaluated independently, for the 19 venous axes of the legs: 1: the interpretability of the examination, 2: the differential diagnosis between: absence of thrombus, presence of thrombus, nonconclusive examination, and 3: the score for the DVT extension. Evaluation of concordance of diagnosis was by Cohen's kappa coefficient, calculated on the positive diagnosis of DVT and the site of the most proximal thrombus. Extension scores were compared by calculation of the coefficient of correlation "r". Interpretability rates were 92% and 91% respectively for the two operators, 35 DVT being diagnosed in 27 patients by operator A and 36 DVT in 27 patients by operator B. The kappa coefficient for diagnosis of DVT with localization in the affected leg was 0.90 [0.81-0.98]. It was 0.89 [0.73-1] for proximal lesions, 0.86 [0.74-0.97] for the lower leg level, and 0.79 for localization of the proximal extremity of the thrombus. Extension scores evaluated by the two operators were 2.88 and 3.14 respectively, with a coefficient of correlation between the extension scores of 0.96. The 5 diagnostic divergences concerned the lower leg level; the 2 localization discordances concerned: the frontier zones leg-lower popliteal, lower femoral-upper popliteal. Good concordance between results of the two operators using Duplex-ultrasonography exploration was obtained even though the majority of the DVT were in the calf, a region known to be explored with difficulty. Overcoming the operator-dependent character of Duplex-ultrasonography by a rigorous exploratory methodology could make it the future reference examination for the diagnosis of DVT.