New Computer-Aided Diagnosis of Dementia Using Positron Emission Tomography: Brain Regional Sensitivity-Mapping Method

Purpose: We devised a new computer-aided diagnosis method to segregate dementia using one estimated index (Total Z score) derived from the Brodmann area (BA) sensitivity map on the stereotaxic brain atlas. The purpose of this study is to investigate its accuracy to differentiate patients with Alzheimer’s disease (AD) or mild cognitive impairment (MCI) from normal adults (NL). Methods: We studied 101 adults (NL: 40, AD: 37, MCI: 24) who underwent 18FDG positron emission tomography (PET) measurement. We divided NL and AD groups into two categories: a training group with (Category A) and a test group without (Category B) clinical information. In Category A, we estimated sensitivity by comparing the standard uptake value per BA (SUVR) between NL and AD groups. Then, we calculated a summated index (Total Z score) by utilizing the sensitivitydistribution maps and each BA z-score to segregate AD patterns. To confirm the validity of this method, we examined the accuracy in Category B. Finally, we applied this method to MCI patients. Results: In Category A, we found that the sensitivity and specificity of differentiation between NL and AD were all 100%. In Category B, those were 100% and 95%, respectively. Furthermore, we found this method attained 88% to differentiate ADconverters from non-converters in MCI group. Conclusions: The present automated computer-aided evaluation method based on a single estimated index provided good accuracy for differential diagnosis of AD and MCI. This good differentiation power suggests its usefulness not only for dementia diagnosis but also in a longitudinal study.浜松医科大学学位論文　医博第695号（平成27年3月16日

Incidence and characteristics of uterine leiomyomas with FDG uptake

OBJECTIVE: Uterine leiomyomas sometimes show focal 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) images that may result in a false-positive diagnosis for malignant lesions. This study was conducted to investigate the incidence and characteristics of uterine leiomyomas that showed FDG uptake. METHODS: We reviewed FDG-PET and pelvic magnetic resonance (MR) images of 477 pre-menopausal (pre-MP, age 42.1 +/- 7.3 years) and 880 post-MP (age 59.9 +/- 6.8 years) healthy women who underwent these tests as parts of cancer screening. Of 1357, 323 underwent annual cancer screening four times, 97 did three times, 191 did twice, and the rest were screened once. Focal FDG uptake (maximal standardized uptake value > 3.0) in the pelvis was localized and characterized on co-registered PET/MR images. RESULTS: Uterine leiomyomas were found in 164 pre-MP and 338 post-MP women. FDG uptake was observed in 18 leiomyomas of 17 of the 164 (10.4%) pre-MP women and in 4 leiomyomas of 4 of the 338 (1.2%) post-MP women. The incidence was significantly higher in pre-MP women than in post-MP women (chi-square, P < 0.001). Of the 22, 13 showed signal intensity equal to or higher than that of the myometrium on T2-weighted MR images, which suggested abundant cellularity, whereas the majority of leiomyomas without FDG uptake showed low signal intensity. Of the 13 women, 12 examined more than twice showed substantial changes in the level of FDG uptake in leiomyomas each year with FDG uptake disappearing or newly appearing. These changes were observed frequently in relation with menopause or menstrual phases. CONCLUSIONS: Leiomyomas with focal FDG uptake were seen in both pre-and post-MP women with a higher incidence in pre-MP women. Abundant cellularity and hormonal dependency may explain a part of the mechanisms of FDG uptake in leiomyomas. It is important to know that the level of FDG uptake in leiomyomas can change and newly appearing FDG uptake does not necessarily mean malignant transformation

Prospective evaluation of whole-body cancer screening with multiple modalities including 18F-fluorodeoxyglucose positron emission tomography in a healthy population: a preliminary report

PURPOSE: To prospectively evaluate the utility of whole-body cancer screening with multiple modalities including [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in a healthy population. This report summarizes the results of the first three annual screenings. PARTICIPANTS AND METHODS: A total of 1,197 healthy volunteers > or = 35 years old were enrolled between August 2003 and July 2004 and offered annual cancer screening for 5 years with subsequent long-term follow-up. Screening modalities included were whole-body FDG-PET, chest and abdominal computed tomography (CT), brain and pelvic magnetic resonance imaging, several tumor markers, and fecal occult blood testing. RESULTS: As of the end of 2006, 22 primary cancers were pathologically confirmed. Nineteen of 22 were detected by the screening; 18 in the initial, one in the second, and none in the third. Three were diagnosed after development of symptoms. Of the 18 detected in the initial screening (six thyroid, four lung, three prostate, three breast, one endometrial, and one thymic), 12 were at stage I and 11 were PET positive. PET-negative cancers were detected by CT or the prostate-specific antigen (PSA) test. Sensitivity and specificity were 50.0% (11 of 22) and 93.2% (1,095 of 1,175), respectively, for FDG-PET alone and 81.8% (18 of 22) and 82.0% (963 of 1,175), respectively, for the combination of imaging modalities and PSA. CONCLUSION: While FDG-PET alone is insufficient, whole-body cancer screening with selected modalities including FDG-PET has initial performance supporting possible utility by detecting a wide variety of early-stage cancers with reasonable sensitivity. However, the detection of many indolent cancers and false positives necessitate continuing study for appropriate evaluation