Percutaneous radiofrequency ablation of lung tumors with expandable needle electrodes: current status.

Percutaneous radiofrequency thermal ablation (RFA) has been used to treat primary and secondary liver tumors under ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) guidance for the past decade [Park et al., Radiol Clin North Am 38:545-561, 2000; Siperstein and Gotomirski, Cancer J 6:S293-S301, 2000; Kelekis et al., Eur Radiol 13:1100-1105, 2003]. RFA is a low-cost, minimally invasive treatment that has recently attracted attention for treating tumors in different solid organs with promising results [Dupuy and Goldberg, J Vasc Interv Radiol 12:1135-1148, 2001; Friedman et al., Cardiovasc Intervent Radiol 27:427-434, 2004]. It can be provided with minimal hospitalization, and experienced practitioners have reported low complication rates [Dupuy and Goldberg, J Vasc Interv Radiol 12:1135-1148, 2001; Livraghi et al., Radiology 226:441-451, 2003]. Patients with lung malignancies (primary lung cancer or pulmonary metastases), who cannot be operated, might be candidates for RFA treatment. It can also be used in association with other treatments (i.e., chemotherapy, radiotherapy) for better disease control. Combination of the above with RFA may help reduce morbidity and mortality. Many ways to apply energy to the tumor exist (monopolar and bipolar RFA, microwave, laser, brachytherapy). In this review we will focus on expandable monopolar systems, which despite their deficiencies are the most popular in the interventional radiology sector.

Uptake and washout of 99mTcV-dimercaptosuccinic acid and 99mTc-sestamibi in the assessment of histological type and grade in breast cancer.

This study was performed to investigate the relationship between histological type and grade, with the uptake and washout of 99mTc-hexakis-2-methoxyisobutylisonitrile (99mTc-sestamibi, 99mTc-MIBI) and 99mTcV-dimercaptosuccinic acid (99mTcV-DMSA) in breast cancer. Forty-five patients with histologically proven breast cancer had previously been referred for 99mTcV-DMSA and/or 99mTc-MIBI scintimammography. Twenty-five of them underwent both 99mTcV-DMSA and 99mTc-MIBI scintigraphy in a double phase study. Lateral prone and anterior supine images were acquired at 15 and 60 min after administration of 740-925 MBq of each radiotracer. Uptake ratios and retention index were calculated and correlated with histology and grade of malignancy. Histology showed eight different histotypes: 77.7% were infiltrating ductal or lobular carcinomas. Mammography was definitely positive in 32/45, indeterminate in 10 and negative in three cases (sensitivity 71%). 99mTcV-DMSA was true positive in 37/40 (sensitivity 92.5%) and 99mTc-MIBI in 28/30 (sensitivity 93.3%) breast cancers. Uptake ratios were significantly higher in ductal than in lobular carcinomas on 99mTcV-DMSA and 99mTc-MIBI scintigrams at early and delayed phases. Grade II carcinomas had significantly lower values of retention index (rapid washout) than grade III carcinomas. This finding was statistically significant only on 99mTc-MIBI scans and was observed in ductal and lobular carcinomas. The retention index did not show any significant difference between ductal and lobular carcinomas. Uptake ratios were also not statistically different between grade II and III cancers. It is concluded that 99mTc-MIBI and 99mTcV-DMSA uptake in breast cancer is probably related to histological type and may distinguish ductal from lobular carcinomas. To a certain degree, the washout rate may reflect the histological grade, but since grade is not the only factor influencing this phenomenon it should be explored further in conjunction with other parameters by multivariate analysis in order to clarify eventual indirect correlations.

99mTc-(V)DMSA scintimammography in the assessment of breast lesions: comparative study with 99mTc-MIBI.

The purpose of this study was to evaluate and compare the diagnostic accuracy of pentavalent technetium-99m dimercaptosuccinic acid [99mTc-(V)DMSA] and 99mTc-methoxyisobutylisonitrile (MIBI) in the detection of primary breast cancer and metastatic lymph node involvement, and in the clarification of cases with indeterminate mammograms. Forty-one women (mean age+/-SD 55+/-7 years) referred for a suspicious breast lesion on physical examination and/or an abnormal mammogram underwent MIBI and (V)DMSA scintimammography (SMM) at separate sessions (48-h interval). Lateral prone and anterior supine images were obtained at 10 and 60 min after administration of 740-925 MBq of each tracer, in the arm contralateral to the breast lesion. The ipsilateral axillary region was also included in the field of view. The results of SMM and mammography were compared with histological findings. Breast cancer was histologically confirmed in 26 patients (mean diameter+/-SD 2.87+/-1.5 cm). Benign lesions were found in 15 patients (mean diameter+/-SD 2.04+/-2.7 cm). Mammography was definitely positive in 23/26 patients with breast cancer and indeterminate in 3/26 (sensitivity 88.4%). In benign lesions, mammography was true negative in 5/15 cases and indeterminate in 10/15 (specificity 33.3%). Both MIBI and (V)DMSA SMM detected 23/26 breast cancers (sensitivity 88.4%) and were true negative in 14/15 (specificity 93.3%). T/B ratios for breast cancer in MIBI and (V)DMSA scans were similar, and significantly higher than for benign lesions. MIBI correctly diagnosed 12/13 and (V)DMSA 11/13 cases in which the findings of mammography were indeterminate. In addition, (V)DMSA detected seven of eight cases of in situ ductal carcinoma (DCIS) associated with infiltrating carcinomas, while MIBI detected only two of these eight cases. (V)DSMA was also diffusely concentrated in benign lesions complicated by epithelial hyperplasia. Metastatic lymph node involvement was successfully imaged in 15/19 patients with metastatic disease by both agents (sensitivity 78.9%), while true-negative scans were observed in 19/22 (specificity 86.3%) patients with benign or malignant tumours without lymph node metastases. Linear regression analysis revealed a high coefficient of correlation between the (V)DMSA and the MIBI T/B ratios (r=0.8 P<0.001). We conclude that both (V)DMSA and MIBI show an excellent ability to detect breast cancer and its lymph node metastases. (V)DMSA also has a tendency to be diffusely and more intensely localised than MIBI in pre-invasive lesions, such as DCIS or epitheliosis, which are at risk of developing into malignancies. (V)DMSA could therefore provide a useful tool in the diagnosis of such lesions and possibly modify a predefined surgical plan. Finally, we believe that both tracers could offer an alternative method for elucidating nondiagnostic mammograms.

Scintimammographic findings of in situ ductal breast carcinoma in a double-phase study with Tc-99m(V) DMSA and Tc-99m MIBI value of Tc-99m(V) DMSA.

The authors present a case of in situ ductal carcinoma of the breast (DCIS) with no associated mass in a 46-year-old woman examined with Tc-99m MIBI and Tc-99m(V) DMSA scans, which were acquired in separate sessions 10 minutes and 60 minutes after injection. Histologic analysis revealed a small (<1 cm) infiltrating ductal carcinoma located within the DCIS. Mammography showed a cluster of microcalcifications on a very dense parenchymal background. Tc-99m(V) DMSA was characterized as positive for DCIS, especially in the delayed image. Tc-99m MIBI failed to identify the lesions previously noted. In conclusion, Tc-99m(V) DMSA scintimammography seems to have an advantage and could improve the detection of nonpalpable in situ breast carcinomas.