Munenobu Nogami

Evaluation of the potential of PET-MRI fusion for detection of liver metastases in patients with neuroendocrine tumours

AbstractObjectivesThis study was performed to assess the role of retrospective PET-MRI fusion with Ga-68-DOTA(0)-Phe(1)-Tyr(3)-octreotide (Ga-68-DOTATOC) PET and Gd-EOB-DTPA MRI in the detection of hepatic metastases from neuroendocrine tumours (NET).MethodsTwenty-two consecutive patients with suspected liver metastases from histopathologically proven NET were examined with Gd-EOB-DTPA MRI and multiphase contrast-enhanced Ga-68-DOTATOC PET/CT. PET and MRI images were retrospectively fused using commercially available software. Two physicians experienced in nuclear medicine and radiology analysed the images to assess diagnostic confidence and characterise liver lesions.ResultsA total of 181 lesions were detected. PET-MRI showed a sensitivity of 91.2% (significantly superior to PET/CT; P < 0.05) and a specificity of 95.6% (significantly superior to MRI; P < 0.05). PET/CT had a sensitivity of 73.5% and a specificity of 88.2%. MRI had a sensitivity of 87.6% and a specificity of 86.8%. The area under the curve was 0.98 for PET-MRI, 0.96 for MRI, and 0.89 for PET/CT (P < 0.05).ConclusionsRetrospectively fused PET-MRI was superior to multiphase contrast-enhanced Ga-68-DOTATOC PET/CT and Gd-EOB-DTPA MRI in the detection of NET liver metastases. It was more sensitive than PET/CT and more specific than MRI. Fused PET-MRI therefore seems well suited for surgical and interventional treatment planning of NET liver metastases.Key Points• Ga-68-DOTATOC PET–Gd-EOB-DTPA MRI fusion can improve imaging of liver metastases of neuroendocrine tumours.• This technique appears more sensitive than PET/CT for staging NET hepatic metastases. • Ga-68-DOTATOC PET–Gd-EOB-DTPA MRI fusion is more specific than MRI alone.

Early prediction of response to neoadjuvant chemotherapy in patients with breast cancer using diffusion-weighted imaging and gray-scale ultrasonography.

Neoadjuvant chemotherapy (NACT) is a widely accepted therapeutic option for patients with breast cancer. Although NACT produces good results for breast cancer patients, it has the potential to delay effective treatment in patients with chemotherapy-resistant breast cancer. The purpose of the present study was to evaluate the utility of the pretreatment apparent diffusion coefficient (ADC), which is calculated from diffusion-weighted imaging (DWI), the change in ADC after first administration of NACT, and the change in tumor greatest diameter on ultrasonography in the early prediction of the tumor response to NACT. The response rate of breast tumors to NACT was calculated by the greatest diameter measured by contrast-enhanced MRI obtained before and after NACT. Only the change in ADC was significantly correlated with the response rate. The area under the curve of the change in ADC was sufficiently high (0.90, 95% confidence interval, 0.760–1.040) to discriminate between responders and non-responders. Calculation of the ADC from DWI-MRI was found to be useful for predicting breast tumor response to NACT. Further studies are required to investigate the benefit of changing systemic therapy for breast cancer based on the prediction of the response to NACT by DWI-MRI.

Pulmonary FDG uptake without a CT counterpart – a pitfall in interpreting PET/CT images:

Abnormal pulmonary 18F-FDG foci may occur with benign lesions like pneumonia but seldomly without any pathological CT findings. We report the case of a focal pulmonary 18F-FDG uptake without CT correlate in an initial staging examination of a patient with squamous cell carcinoma of the base of the tongue. A follow-up study did not show any suspicious lesion in this area, but pneumonia with 18F-FDG uptake in another region of the lung. 18F-FDG foci without pathological CT are a rare finding and have been associated with emboli. In the literature two main mechanisms underlying focal 18F-FDG uptake in pulmonary embolism are mentioned: an inflammatory reaction of a pre-existing vascular thrombus and an iatrogenic microembolism caused during injection. In our case the 18F-FDG accumulation was assessed as an iatrogenic pulmonary microembolism.

Safety and efficacy of image-guided enzyme-targeting radiosensitization and intraoperative radiotherapy for locally advanced unresectable pancreatic cancer.

A novel radiosensitization treatment involving the injection of hydrogen peroxide and sodium hyaluronate, using ultrasonic guidance, into a tumor immediately prior to intraoperative radiotherapy (IORT) was established for patients with stage IVa locally advanced unresectable pancreatic cancer. The aim of the present study was to assess the safety and efficacy of this novel treatment, termed Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas-IORT (KORTUC and IORT). In total, 12 patients were treated with KORTUC-IORT, external-beam radiotherapy and systemic chemotherapy using gemcitabine hydrochloride and S-1. For evaluation of the therapeutic and adverse effects, contrast-enhanced computed tomography was conducted prior to the treatment, and one and six months following KORTUC-IORT. Medical examinations were performed every month at the regularly scheduled follow-up visits. The one- and two-year survival rates were 75 and 25%, respectively, and the median survival time was 16 months. All treatments associated with KORTUC-IORT were well-tolerated by the patients, with a small number of adverse effects and no serious complications. It was identified that the delivery of KORTUC-IORT is safe and effective, in combination with external-beam radiotherapy and systemic chemotherapy, for patients with locally advanced unresectable pancreatic cancer.

Reduction of fibroproliferative changes in irradiated rat lung with soluble transforming growth factor-β receptor

The present study investigated whether established fibroproliferative changes in the irradiated rat lung are histopathologically reduced by an adenovirus‑mediated soluble transforming growth factor (TGF)‑β type II receptor. Replication‑defective adenoviral vectors expressing a type II human TGF‑β receptor (AdTβ‑ExR) were prepared. Male Fisher‑344 rats were divided into the C, R and R + T groups. The rats in the C group did not receive irradiation or treatment. The rats in the R and R + T group each received 30 Gy irradiation to the right lung. Eight weeks following irradiation, the rats in the R and R + T group were treated with saline or AdTβ‑ExR, respectively. To analyze the TGF‑β expression, myofibroblast proliferation and macrophage/monocyte infiltration, sections of the lung were immunohistochemically stained at 16 weeks following irradiation. Silver staining was performed for semi‑quantitative evaluation of the fibroproliferative changes. Definitive TGF‑β expression, myofibroblast proliferation and macrophage/monocyte infiltration were observed in the lungs of the R group, but were significantly lower in the lungs of the R + T group. With respect to the fibroproliferative changes, the proportion of red‑stained areas in the R + T group was markedly lower than that in the R group. These data indicate that fibroproliferative changes induced by radiation are reversible and that TGF‑β has a critical role in fibroproliferative changes in the irradiated lung. The present results suggest that gene therapy with an adenoviral vector expressing a soluble TGF‑β receptor may be effective in reducing the established pulmonary fibrosis caused by radiation.