Pathophysiology characterization of Alzheimer's disease in South China's aging population: for the Greater-Bay-Area Healthy Aging Brain Study (GHABS).

INTRODUCTION: The Guangdong-Hong Kong-Macao Greater-Bay-Area of South China has an 86 million population and faces a significant challenge of Alzheimer's disease (AD). However, the characteristics and prevalence of AD in this area are still unclear due to the rarely available community-based neuroimaging AD cohort. METHODS: Following the standard protocols of the Alzheimer's Disease Neuroimaging Initiative, the Greater-Bay-Area Healthy Aging Brain Study (GHABS) was initiated in 2021. GHABS participants completed clinical assessments, plasma biomarkers, genotyping, magnetic resonance imaging (MRI), ß-amyloid (Aß) positron emission tomography (PET) imaging, and tau PET imaging. The GHABS cohort focuses on pathophysiology characterization and early AD detection in the Guangdong-Hong Kong-Macao Greater Bay Area. In this study, we analyzed plasma Aß42/Aß40 (A), p-Tau181 (T), neurofilament light, and GFAP by Simoa in 470 Chinese older adults, and 301, 195, and 70 had MRI, Aß PET, and tau PET, respectively. Plasma biomarkers, Aß PET, tau PET, hippocampal volume, and temporal-metaROI cortical thickness were compared between normal control (NC), subjective cognitive decline (SCD), mild cognitive impairment (MCI), and dementia groups, controlling for age, sex, and APOE-ε4. The prevalence of plasma A/T profiles and Aß PET positivity were also determined in different diagnostic groups. RESULTS: The aims, study design, data collection, and potential applications of GHABS are summarized. SCD individuals had significantly higher plasma p-Tau181 and plasma GFAP than the NC individuals. MCI and dementia patients showed more abnormal changes in all the plasma and neuroimaging biomarkers than NC and SCD individuals. The frequencies of plasma A+/T+ (NC; 5.9%, SCD: 8.2%, MCI: 25.3%, dementia: 64.9%) and Aß PET positivity (NC: 25.6%, SCD: 22.5%, MCI: 47.7%, dementia: 89.3%) were reported. DISCUSSION: The GHABS cohort may provide helpful guidance toward designing standard AD community cohorts in South China. This study, for the first time, reported the pathophysiology characterization of plasma biomarkers, Aß PET, tau PET, hippocampal atrophy, and AD-signature cortical thinning, as well as the prevalence of Aß PET positivity in the Guangdong-Hong Kong-Macao Greater Bay Area of China. These findings provide novel insights into understanding the characteristics of abnormal AD pathological changes in South China's older population.

FDG PET/CT in a Case of Primary Lymphoma of the Ureter.

ABSTRACT: Primary lymphoma of the ureter is extremely rare. We describe the contrast-enhanced CT and FDG PET/CT findings in a case of diffuse large B-cell lymphoma transformed from mucosa-associated lymphoid tissue lymphoma limited to the left ureter. Contrast-enhanced CT showed 2 short-segment circumferential thickening and enhancement of the left pelvic and intramural ureteral wall. The thickened ureteral wall showed significantly increased FDG uptake mimicking urothelial carcinoma.

Incremental value of combinatorial contrast echocardiography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography in giant right atrial myxomas.

Although several studies have shown that myocardial contrast echocardiography and 18-FDG PET/CT can differentiate between benign and malignant intracardiac masses, it is rarely used in practice to evaluate myxoma. This case describes the contrast echocardiography and 18-FDG PET/CT findings of a giant myxoma with an atypical location and subclinical symptoms.

FDG PET/CT of Primary Breast Lymphoma in a Man.

ABSTRACT: Primary lymphoma of the male breast is extremely rare. We describe FDG PET/CT findings in a man with primary breast lymphoma in his right breast. The breast tumor showed intense FDG uptake mimicking breast carcinoma.

FDG PET/CT Findings of Melanoma in a Renal Allograft.

Renal melanoma is rare. We present a case with FDG-avid melanoma arising from renal allograft. This case indicates that melanoma can occur in the allograft, and it should be considered as a differential diagnosis of focal abnormal FDG uptake in the renal allograft.

FDG PET/CT in a Case of Bilateral Tuberculous Epididymo-orchitis.

Isolated genital tuberculosis is rare. We present a case of bilateral tuberculous epididymo-orchitis showing high FDG uptake on FDG PET/CT. In addition, the patient had a prostatic FDG-avid lesion, consistent with tuberculous prostatitis. This case indicates tuberculous epididymo-orchitis, especially in tuberculosis-endemic regions, should be considered as a differential diagnosis in patients with hypermetabolic epididymal or testicular lesions, including benign and malignant tumors, bacterial epididymo-orchitis, abscess, idiopathic granulomatous orchitis, and sarcoidosis.

FDG PET/CT in a Case of Dural Amyloidoma.

Dural amyloidoma is an unusual presentation of central nervous system amyloidosis. A 49-year-old woman presented with 1-month history of repeated episodes of vertigo. Precontrast MRI showed dural thickening over right frontal convexity with signal intensity similar to white matter. Postcontrast T1-weighted images showed remarkable enhancement of the lesion. Dural amyloidoma was confirmed by partial resection of the lesion. The patient underwent no further treatment. A follow-up FDG PET/CT showed increased FDG uptake of the residual dural amyloidoma. This case indicates dural amyloidoma should be included in the differential diagnosis of abnormal FDG uptake in dural lesions.

Increased FDG Uptake in a Giant Bone Island Mimicking Malignancy.

Histologically proven bone islands exhibiting increased FDG uptake have been rarely reported before. We present a case with active giant bone island in the left humerus showing increased FDG uptake with SUVmax of 3.8. The diagnosis was confirmed by open biopsy and follow-up. Increased osteoblastic activity, proliferating and active fibroblasts, and increased blood flow may contribute to the increased FDG uptake of this giant bone island. This case indicates bone island should be included in the differential diagnosis of abnormal FDG uptake in focal sclerotic bone lesions, especially in patients with known malignancy.

Sarcomatoid renal cell carcinoma: a case report and literature review.

BACKGROUND: The poorly differentiated renal cell carcinoma (RCC) with rhabdomyosarcomatous sarcomatoid differentiation shows a severely aggressive biological behavior characterized by rapid disease progression. Preoperative identification of the subtype with the prognostic factors and imaging features of sarcomatoid renal cell carcinoma (SRCC) would be of great clinical significance. CASE PRESENTATION: A 45-year-old male patient presented a nine day history of gross hematuria without any other symptoms. A computed tomography (CT) and a full-body fluorine-18 fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) - computed tomography (CT) scan urogram were performed. An initial diagnosis identified a space-occupying lesion of the right kidney, retroperitoneal and right renal hulum lymph node metastases, as well as a space-occupying lesion of the third thoracic vertebra (T3). A right radical nephrectomy was performed. Pathologic analysis revealed poorly differentiated RCC with rhabdomyosarcomatous sarcomatoid differentiation that extends into the renal sinus and the ureteral (T3N1M1). Five days later, the Magnetic Resonance imaging (MRI) evidenced a diffused osseous metastatic disease in the thoracic and lumbar vertebra and multiple retroperitoneal lymph node metastases. The disease progressed quickly to multiple organ dysfunction syndrome (MODS) in half a month and the patient died of respiratory failure two days later. The patient refused any chemoradiotherapy in the hospital. CONCLUSIONS: Our case presents a SRCC with severe, aggressive, and rapid disease progression. Classifying SRCC imaging features by CT, MRI as well as PET-CT techniques could potentially be helpful for preoperative identification of the subtype. The prognostic factors of SRCC would be of great clinical interest.

[A fMRI observation on different cererbral regions activated by acupuncture of Shenmen (HT 7) and Yanglao (SI 6)].

OBJECTIVE: To observe the influence of acupuncture of Shenmen (HT 7) and Yanglao (SI 6) on neuro-images in different cerebral regions in volunteer subjects. METHODS: Twelve healthy young volunteer participants were enrolled in this research. fMRI scans were taken in random order in a block design (one for baseline and two for acupuncture stimulations). During stimulation phase, an acupuncture needle inserted in right HT7 or S16 was twirled at an angle of 180 degrees and a frequency of about 1.5 Hz for 35. 6 ms. Main parameters for fMRI were TR/TE/FA = 3560 ms/50 ms/90 degrees. Acupuncture sensations were evaluated by means of visual analog scale (VAS). The collected images were analyzed by using SPM 2 for exploring inter-group differences in blood oxygen level dependent (BOLD) responses. RESULTS: When manipulating the needle, both the operator and the subject had a feeling of Deqi. Increases in BOLD signal (group analysis, corrected, 0.05, K > or =10) were found mainly in right postcentral gyrus of frontal lobe (BA 2, BA 1, BA 43), left inferior frontal gyrus (BA 47), secondarily, in the right inferior parietal lobule (BA 40), right inferior frontal gyrus (BA 44), left superior temporal gyrus (BA 22) and right insula (BA 40) after acupuncture at HT7; and chiefly in left inferior parietal lobule (BA 40), right inferior frontal gyrus (BA 45, BA 46), secondarily in the left middle temporal gyrus and inferior temporal gyrus (BA 37) as well as the left superior frontal gyrus (BA 10) after acupuncture of S16. CONCLUSION: Acupuncture of HT7 and SI6 elicite different BOLD responses in some related cerebral regions.