Takashi Norikane

Correlation of (18)F-fluoromisonidazole PET findings with HIF-1α and p53 expressions in head and neck cancer: comparison with (18)F-FDG PET.

ObjectiveWe evaluated tumor hypoxia using 18F-fluoromisonidazole (18F-FMISO) PET in relation to the expression of hypoxia-inducible factor-1&agr; (HIF-1&agr;) and p53 in patients with head and neck cancer and compared the results with those obtained using 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) PET. Materials and methodsA total of 28 tumors (23 primary tumors and five metastatic lymph nodes) from 24 patients with newly diagnosed head and neck cancer were examined with 18F-FMISO PET and 18F-FDG PET. The 18F-FMISO PET images were scaled to the venous blood concentration of 18F-FMISO activity to produce tumor-to-blood (T/B) values. Hypoxia was defined as a region with a T/B ratio greater than or equal to 1.2. The maximum T/B (T/Bmax) and hypoxic volumes were calculated by region-of-interest analysis. For 18F-FDG PET, the maximum standardized uptake value (SUVmax) and hypermetabolic volume were calculated by region-of-interest analysis. The expressions of HIF-1&agr; and p53 using immunohistochemistry were estimated in tumor tissue samples. ResultsA weak correlation was observed between hypoxic volume and T/Bmax (r=0.53, P=0.003) on using 18F-FMISO PET and between hypermetabolic volume and SUVmax (r=0.38, P=0.046) on using 18F-FDG PET. The hypoxic volume using 18F-FMISO PET and hypermetabolic volume using 18F-FDG PET also showed a weak correlation (r=0.44, P=0.020). The values of 18F-FMISO hypoxic volume showed a weak correlation with HIF-1&agr; (r=0.40, P=0.037) and p53 (r=0.47, P=0.012) obtained on immunohistochemical examination. ConclusionThis study demonstrates a weak correlation between hypoxic volume measured by 18F-FMISO PET and expressions of HIF-1&agr; and p53 in head and neck cancer.

Hypertrophic cranial pachymeningitis with IgG4-positive plasma cells detected by C-11 methionine PET.

A 53-year-old man who presented with mild headache and ophthalmodynia underwent carbon-11 methionine (MET) positron emission tomography (PET). MET PET images demonstrated intense uptake in the periphery of the brain, significantly higher than the physiological uptake in the brain. Biopsy specimens f

A case of primary pericardial mesothelioma detected by 18F-FDG PET/CT.

Primary pericardial mesothelioma is an extremely rare malignancy. We report a case of a 58-year-old woman who presented with fever and fatigue. She had no apparent history of occupational or incidental exposure to asbestos. A postcontrast-enhanced chest CT revealed a 77 × 56-mm mass lesion in the pericardium. The FDG PET/CT was carried out, which demonstrated an intense FDG uptake to a main pericardial tumor and disseminated lesions in the pericardium. Histologic examination confirmed the primary malignant pericardial mesothelioma.

Myocarditis with high 18 F-FDG uptake and no 18 F-FLT uptake

We present a case of myocarditis with increased 18F-FDG uptake and no 18F-fluorothymidine (FLT) uptake.

Early infected aneurysm with 18F-FDG uptake prior to substantial anatomical changes

A 79-year-old female presented with a 2-month history of chest pain. Computed tomography (CT) showed hilar and mediastinal lymphadenopathy and lysis and destruction in the sternum. Bone metastasis was suspected, and she underwent F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT to identify the primary lesion. F-FDG PET/CT images demonstrated avid uptake in the sternum and lymph nodes and focal increased uptake within the wall of the ascending aorta and aortic arch (Figure 1). CT showed no anatomical abnormalities. Three weeks after FFDG PET/CT, contrast-enhanced CT demonstrated aneurysmal dilatation corresponding to the intense FDG uptake (Figure 2). Echocardiography was performed, but it did not show any vegetation or other abnormalities. One month after antibiotic treatment, follow-up F-FDG PET/CT images showed decreased FDG uptake in the sternum and ascending aorta and aortic arch (Figure 3). She finally underwent surgical repair, and pathological examination revealed infection in the aneurysm wall. The sternal lesion was clinically diagnosed as suppurative osteomyelitis. It can be difficult to diagnose infected aneurysm without typical signs. CT can demonstrate anatomical changes of the aorta, but not inflammation of the vessel wall in the early phase because of the absence of anatomical changes. F-FDG PET detects an increased glucose metabolic rate that is characteristic of aortic wall inflammation. Previous reports showed positive results of F-FDG PET/CT studies in patients with infected aneurysm. Moreover, focal F-FDG uptake in aortic aneurysm corresponded to the site of aneurysm rupture. This case highlights the value of F-FDG PET/ CT to diagnose infected aneurysm in the early stage prior to substantial anatomical changes.

Correlation of 4′-[methyl-11C]-thiothymidine uptake with human equilibrative nucleoside transporter-1 and thymidine kinase-1 expressions in patients with newly diagnosed gliomas

ObjectiveWe examined expressions of human equilibrative nucleoside transporter-1 (hENT1) and thymidine kinase-1 (TK1), the key enzyme in 4′-[methyl-11C]-thiothymidine (4DST) phosphorylation, to elucidate the mechanism of 4DST uptake in patients with newly diagnosed gliomas.MethodsA total of 19 patients with newly diagnosed gliomas were examined with 4DST PET. Tumor lesions were identified as areas of focally increased uptake, exceeding that of normal brain background. For semi-quantitative analysis, tumor-to-contralateral normal brain tissue (T/N) ratio was determined by dividing the maximal standardized uptake value (SUV) for tumor by that of the mean SUV for reference tissue. The expressions of hENT1, TK1 and Ki-67 in tumor specimens were examined by immunohistochemistry and compared with 4DST T/N ratio.ResultsAll but two gliomas showed focally increased 4DST uptake. All gliomas showed hENT1 staining, except one grade II glioma, which was also not visualized on 4DST PET. A significant correlation was observed between T/N ratio and hENT1 score (ρ = 0.90, p < 0.001). All gliomas showed TK1 staining, except two gliomas which were also not visualized on 4DST PET. There was a significant correlation between T/N ratio and TK1 score (ρ = 0.92, p < 0.001). There was a significant correlation between T/N ratio and Ki-67 index (ρ = 0.50, p < 0.03).ConclusionResults of this preliminary study indicate that expressions of hENT1 and TK1 appear to be important determinants of 4DST uptake in newly diagnosed gliomas.

Correlation of 18F-FDG and 11C-methionine uptake on PET/CT with Ki-67 immunohistochemistry in newly diagnosed intracranial meningiomas

ObjectiveWe evaluated the uptake of 2-deoxy-2-18F-fluoro-d-glucose (FDG) and l-[methyl-11C]-methionine (MET) in patients with newly diagnosed intracranial meningiomas and correlated the results with tumor proliferation.MethodsData from 22 patients with newly diagnosed intracranial meningioma (12 grade I and 10 grade II) who underwent both FDG and MET brain PET/CT studies were retrospectively analyzed. The PET images were evaluated by a qualitative method and semiquantitative analysis using standardized uptake value (SUV) (SUVmax and SUVpeak) and tumor-to-reference tissue ratio (Tmax/N ratio and Tpeak/N ratio). Proliferative activity as indicated by the Ki-67 index was estimated in tissue specimens.ResultsMET PET/CT showed a higher detection rate of meningioma than did FDG PET/CT (100 vs. 46%, respectively). The Tmax/N ratio and Tpeak/N ratio on MET PET/CT were significantly higher than those on FDG PET/CT (p < 0.001 and p < 0.001, respectively). There was a significant difference between grades I and II with respect to FDG SUVmax (p = 0.003), FDG SUVpeak (p = 0.003), FDG Tmax/N ratio (p = 0.02), FDG Tpeak/N ratio (p = 0.006), MET SUVmax (p = 0.002), MET SUVpeak (p = 0.002), MET Tmax/N ratio (p = 0.002), and MET Tpeak/N ratio (p = 0.002). There was a significant correlation between Ki-67 index and FDG PET/CT for SUVmax (p = 0.02), SUVpeak (p = 0.005), and Tpeak/N ratio (p = 0.05) and between Ki-67 index and MET PET/CT for SUVmax (p = 0.004), SUVpeak (p = 0.007), Tmax/N ratio (p = 0.002), and Tpeak/N ratio (p = 0.004).ConclusionMET PET/CT showed a high sensitivity compared with FDG PET/CT for detection of newly diagnosed WHO grades I and II intracranial meningiomas. Both FDG and MET uptake were found to be useful for evaluating tumor proliferation in meningiomas.