Accuracy and role of contrast-enhanced CT in diagnosis and surgical planning in 88 soft tissue tumours of extremities.

OBJECTIVES: Soft tissue tumours (STT) require accurate diagnosis in order to identify potential malignancies. Preoperative planning is fundamental to avoid inadequate treatments. The role of contrast-enhanced computed tomography (CT) for local staging remains incompletely assessed. Aims of the study were to evaluate CT accuracy in discriminating active from aggressive tumours compared to histology and evaluate the role of CT angiography (CTA) in surgical planning. MATERIALS AND METHODS: This retrospective cohort series of 88 cases from 1200 patients (7 %) was locally studied by contrast-enhanced CT and CTA in a referral centre: 74 malignant tumours, 14 benign lesions. Contrast-enhancement patterns and relationship of the mass with major vessels and bone were compared with histology on surgically excised samples. Sensitivity, specificity, positive and negative predictive values (PPV, NPV) were evaluated in discriminating active from aggressive tumours. RESULTS: Sensitivity in differentiating aggressive tumours from active lesions was 89 %, specificity 84 %, PPV 90 %, NPV 82 %. The relationship between mass and major vessels/bone was fundamental for surgical strategy respectively in 40 % and in 58 % of malignant tumours. CONCLUSION: Contrast-enhanced CT and CTA are effective in differentiating aggressive masses from active lesions in soft tissue and in depicting the relationship between tumour and adjacent bones and major vessels. KEY POINTS: • Accurate delineation of vascular and bony involvement preoperatively is fundamental for a correct resection. • CT plays a critical role in differential diagnosis of soft tissue masses. • Contrast-enhanced CT and CT angiography are helpful in depicting tumoral vascular involvement. • CT is optimal for characterization of bone involvement in soft tissue malignancies.

Osteoid osteoma: our experience using radio-frequency (RF) treatment.

PURPOSE: To present the results of two years experience with a minimally invasive radio-frequency technique designed by our team in the treatment of osteoid osteoma. MATERIALS AND METHODS: A total of 21 osteoid osteoma patients (15 males, 6 females, age range 13 to 34 yrs) were treated between January 2001 and April 2003. Localizations of the osteoid osteoma were the pelvis (n = 1), the femur (n = 12), the tibia (n = 3), the foot (n = 3), and the humerus (n = 2). All patients underwent an X-ray examination, a CT scan and a bone Scintiscan. In the initial phase, a K-wire just slightly larger than the 17G needle electrode is positioned manually at the zenith of the target area under CT guidance and using an orthopaedic drill it is inserted at the centre of the nidus. A tailor-made metal sheath is inserted on the K-wire to create a ''tunnel'' through which the needle electrode can substitute the K-wire; at the same time, the electrode needle is positioned inside the lesion. The temperature of the exposed tip of the needle is 90 degrees C and duration of hyperthermia is 6 minutes on average. Once the procedure has been completed, a scan os performed to measure the density of the treated site and this measurement is then used as an evolution index for the evaluation of the healing process during follow-up. RESULTS: No serious complications were observed at follow-up. General anaesthesia was only required in the case with hip involvement; peripheral anaesthesia was used in all the other cases. Complete resolution of the pain was reported in all cases after a maximum of three weeks. DISCUSSION AND CONCLUSIONS: After two years experience, we believe percutaneous RF treatment of osteoid osteoma to be the first choice technique when compared to traditional surgery due to the fact that it is almost non-invasive, quick, repeatable if need be and offers a high reduction in costs. Moreover early weight bearing is the norm and the patient is dismissed after only one day of hospitalization. The clinical results indicate a 100% success rate with complete remission of symptoms and no relapses having been reported at the time of writing for those patients who have arrived at the two year follow up (4 out of 21).