PET/Computed Tomography and Thermoablation (Radiofrequency, Microwave, Cryotherapy, Laser Interstitial Thermal Therapy)

Artifactual Hepatic Metastasis on FDG PET/CT Secondary to Cryoablation for Adrenal Metastasis

A 65-year-old woman with metastatic lung cancer was referred for CT-guided cryoablation of a right adrenal metastasis. For cryoablation, probes were placed into the adrenal region. FDG PET/CT 3 months later showed new activity in hepatic segment 6 initially suspected to be metastasis. Proximity of the hepatic lesion to the adrenal metastasis was a strange coincidence and prompted review of imaging from the cryoablation. CT showed the probe entered the liver, and postablation image demonstrated injury to the liver adjacent to the adrenal metastasis. Careful review of treatment history and imaging from ablation procedures are important to avoid this pitfall.

Clinical analysis on 113 patients with lung cancer treated by percutaneous CT-guided microwave ablation

BACKGROUND

Lung Cancer is a primary tumor with poor prognosis. For early stage lung cancer, treatment options include surgical resection and microwave techniques. Percutaneous ablative techniques emerged as best therapeutic options for nonsurgical patients.

METHODS

The aim of this study was to retrospectively analyze the clinical effect of CT-guided microwave ablation (MWA) treatment for patients with lung cancer who were not eligible for surgical resection. MWA was used to treat the tumor lesion of 113 patients with lung cancer who were in our hospital from Jan, 2013 to Jun, 2015. The median diameter of tumors was 3.1 cm (0.7-6 cm). Follow-up were paid to all the patients who received MWA therapy. The average follow-up was 22.1±8.6 months, and the median follow-up was 18 (7-40) months.

RESULTS

All of 113 cases of patients with lung cancer experienced MWA therapy, and their tumors were found to have vacuolization, lower density and much smaller distinct shrinkage of tumor size with varying degrees. The local progression rate or relapse rate of the whole group was 15.9%. The counterpart of patients in the early-stage group was 5.7% (2/35), and the diameter of tumors in the two patients was more than 3 cm. The local progression rate or relapse rate of patients in advanced-stage group was 20.5%, wherein, 81.3% of local progression or relapse occurred to the patients with a tumorous diameter of more than 3 cm. The results indicated that the patients in advanced-stage group were vulnerable to local progression or relapse, the tumorous with greater diameter had higher incidence of local relapse. No mortality occurred within 30 days after surgery, the survival rate of patients in early-stage group at first, second, third year was respectively 97.1%, 94.1% and 84.7%. The counterpart of patients in advanced-stage group was respectively 93.6%, 87.7% and 71.7%. The difference of survival rate between both groups was not statistically significant (P=0.576). No perioperative deaths occurred, and the main complications i.e., fever, pneumothorax, pleural effusion, hemoptysis, pneumonia, and pain were slight and tolerable.

CONCLUSIONS

MWA is an effective, safe and minimally invasive treatment for the patients with lung cancer who cannot be tolerated by surgical resection.

PET-Based Percutaneous Needle Biopsy

PET can be used to guide percutaneous needle biopsy to the most metabolic lesion, improving diagnostic yield. PET biopsy guidance can be performed using visual or software coregistration, electromagnetic needle tracking, cone-beam computed tomography (CT), and intraprocedural PET/CT guidance. PET/CT-guided biopsies allow the sampling of lesions that may not be clearly visible on anatomic imaging, or of lesions that are morphologically normal. PET can identify suspicious locations within complex tumors that are most likely to contain important diagnostic and prognostic information.