Multiparameter characterisation of vertebral osteoporosis with 3-T MR

PURPOSE

This study was undertaken to evaluate the diagnostic capabilities of 3-Tesla (T) magnetic resonance (MR) in vertebral osteoporosis.

MATERIALS AND METHODS

Thirty subjects (ten healthy controls, ten with osteoporosis but no fracture, ten with osteoporotic vertebral fractures) underwent MR of the lumbar spine. Turbo spin echo (TSE) T1-, T2- and T2- spectral selection attenuated inversion recovery (SPAIR) weighted imaging and spectroscopy for the selective evaluation of water and fat content were performed. The apparent diffusion coefficient (ADC) was calculated, and diffusion tensor imaging (DTI) was performed to create a map of the spatial arrangement of the tissue structures.

RESULTS

Morphological imaging detected recent vertebral fractures. In osteoporotic patients, spectroscopic imaging demonstrated an increase in the saturated fats and a decrease in the ADC, whereas the data provided by DTI demonstrated a bone structure with medium-degree anisotropy.

DISCUSSION

Osteoporosis is characterised by trabecular thinning, with an increase in the intertrabecular spaces, which are filled with fats. The anisotropic study and the subsequent assessment of colour and vector maps can provide a noninvasive tool for assessing the risk of fracture due to osteoporosis.

Integrated multislice CT and Tc-99m Sestamibi SPECT-CT evaluation of solitary pulmonary nodules

PURPOSE

The purpose of this study was to evaluate efficacy of multislice computed tomography (MSCT) and single photon emission computed tomography (SPECT)-CT with Tc-99m Sestamibi in the assessment of solitary pulmonary nodules of uncertain significance. Scintigraphy was performed using a 'hybrid' g-camera that allows simultaneous acquisition of SPECT and CT images, with interesting results in diagnostic oncology.

MATERIALS AND METHODS

Between September 2003 and August 2004, 23 patients with a solitary pulmonary nodule detected on CT underwent SPECT-CT using Tc-99m Sestamibi as a radiotracer. Nodules with positive scintigraphy were immediately subjected to biopsy or surgical resection. Nodules with negative scintigraphy were followed up after 3-4 months by MSCT with automatic segmentation software (Advanced Lung Analysis, ALA) and histological characterisation.

RESULTS

Of the 23 nodules (size range 0.8-2 cm) discovered with MSCT, 11 showed intense uptake of Tc-99m Sestamibi. Ten lesions were true positive: seven adenocarcinomas, one squamous cell carcinoma, one large cell carcinoma and one metastasis. The only false positive was histologically classified as a large cell granuloma. Twelve lesions had negative scintigraphy: five fibrous lesions, three hamartomas, three granulomas and one adenocarcinoma (false negative). Benign nodules without tracer uptake underwent another CT scan 3-4 months later, which confirmed stability of the nodule size. Correlation of Sestamibi SPECT with histology showed sensitivity (Se) of 90.9 %, specificity (Sp) of 91.6 %, diagnostic accuracy of 91.3 %, positive predictive value (PPV) of 90.9% and negative predictive value (NPV) of 91.6 %.

CONCLUSIONS

The integrated use of MSCT and Tc-99m Sestamibi SPECT-CT could be very useful in the management of solitary pulmonary nodules (SPNs). In particular, in our preliminary study, scintigraphy provided significant diagnostic information to differentiate benign from suspicious pulmonary nodules. The use of scintigraphy could be helpful to anticipate histological assessment and surgical treatment of SPNs identified at CT.

Percutaneous Treatment of the Obstructive Uropathy

Purpose

to analyse the technical aspects, the patient's selection criteria, and some useful tactics to reduce the complications of percutaneous nephrostomy and of other interventional procedures to temporarily treat obstructive uropathy (OU), such as double J stent insertion, dilatation of the stricture using high-pressure balloon catheters, removal of renal or ureteral calculi, fistulas treatment.

Materials and Methods

a fluoroscopy table and an ultrasonographic guidance are key elements. Two techniques are employed, either the Seldinger type (wire-guided catheters) or the trocar needle type. Sole contraindication: uncorrectable severe coagulopathy. Most important risk factors are: dendritic calculus, non corrected high blood pressure, obesity, small size kidney, severe scoliosis.

Results

high technical success of the procedure in case of dilated collecting systems (98%); it is minor without dilatation (85%).

Conclusion

percutaneous nephrostomy is indicated in 87% of obstructive uropathy cases. It represents the basic technique allowing other interventional procedures to treat obstructive uropathy; it should be performed by most radiologists following an adequate training with technique and materials.