Cerebral tau pathology in cerebral amyloid angiopathy.

Tau, a hallmark of Alzheimer's disease, is poorly characterized in cerebral amyloid angiopathy. We aimed to assess the clinico-radiological correlations between tau positron emission tomography scans and cerebral amyloid angiopathy. We assessed cerebral amyloid and hyperphosphorylated tau in patients with probable cerebral amyloid angiopathy (n = 31) and hypertensive small vessel disease (n = 27) using 11C-Pittsburgh compound B and 18F-T807 positron emission tomography. Multivariable regression models were employed to assess radio-clinical features related to cerebral tau pathology in cerebral amyloid angiopathy. Cerebral amyloid angiopathy exhibited a higher cerebral tau burden in the inferior temporal lobe [1.25 (1.17-1.42) versus 1.08 (1.05-1.22), P < 0.001] and all Braak stage regions of interest (P < 0.05) than hypertensive small vessel disease, although the differences were attenuated after age adjustment. Cerebral tau pathology was significantly associated with cerebral amyloid angiopathy-related vascular markers, including cortical superficial siderosis (ß = 0.12, 95% confidence interval 0.04-0.21) and cerebral amyloid angiopathy score (ß = 0.12, 95% confidence interval 0.03-0.21) after adjustment for age, ApoE4 status and whole cortex amyloid load. Tau pathology correlated significantly with cognitive score (Spearman's ρ=-0.56, P = 0.001) and hippocampal volume (-0.49, P = 0.007), even after adjustment. In conclusion, tau pathology is more frequent in sporadic cerebral amyloid angiopathy than in hypertensive small vessel disease. Cerebral amyloid angiopathy-related vascular pathologies, especially cortical superficial siderosis, are potential markers of cerebral tau pathology suggestive of concomitant Alzheimer's disease.

Differences in lobar microbleed topography in cerebral amyloid angiopathy and hypertensive arteriopathy.

Lobar cerebral microbleeds are a characteristic neuroimaging finding in cerebral amyloid angiopathy (CAA) but can also be found in hypertensive arteriolosclerosis. We aimed to investigate whether CAA is more associated with intracortical lobar microbleeds than hypertensive arteriosclerosis. Ninety-one survivors of spontaneous intracerebral hemorrhage with at least one lobar microbleed were included and underwent brain MRI and amyloid PET. We categorized lobar microbleeds as intracortical, juxtacortical, or subcortical. We assessed the associations between the lobar microbleed categories and microangiopathy subtypes or cerebral amyloid load based on the Pittsburgh Compound-B PET standardized uptake value ratio (SUVR). Patients with CAA had a higher prevalence of intracortical lobar microbleeds (80.0% vs. 50.8%, P = 0.011) and lower prevalence of subcortical lobar microbleeds (13.3% vs. 60.1%, P < 0.001) than patients with hypertensive arteriolosclerosis. Strictly intracortical/juxtacortical lobar microbleeds were associated with CAA (OR 18.9 [1.9-191.4], P = 0.013), while the presence of subcortical lobar microbleeds was associated with hypertensive arteriolosclerosis (OR 10.9 [1.8-68.1], P = 0.010). Amyloid retention was higher in patients with strictly intracortical/juxtacortical CMBs than those without (SUVR = 1.15 [1.05-1.52] vs. 1.08 [1.02-1.19], P = 0.039). Amyloid retention positively correlated with the number of intracortical lobar microbleeds (P < 0.001) and negatively correlated with the number of subcortical lobar microbleeds (P = 0.018). CAA and cortical amyloid deposition are more strongly associated with strictly intracortical/juxtacortical microbleeds than subcortical lobar microbleeds. Categorization of lobar microbleeds based on anatomical location may help differentiate the underlying microangiopathy and potentially improve the accuracy of current neuroimaging criteria for cerebral small vessel disease.

PET/MRI in Endometrial Cancer: Imaging Biomarkers are Associated with Disease Progression and Overall Survival.

RATIONALE AND OBJECTIVES: To evaluate the association between positron emission tomography (PET)/magnetic resonance imaging (MRI) biomarkers and survival outcomes in patients with endometrial cancer. MATERIALS AND METHODS: Between April 2014 and April 2016, 88 patients with newly diagnosed endometrial cancer participated this prospective study and underwent [18F] fluorodeoxyglucose PET/MRI. Sixty-nine patients with measurable tumors on PET/MRI were included in the image analysis. Imaging biomarkers included the minimum and mean apparent diffusion coefficients (ADCmin and ADCmean), maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumors. The log-rank test and Cox proportional hazards model were used to assess the relationship between imaging biomarkers and survival. RESULTS: After a median follow-up of 80 months, 15 (22%) patients had tumor progression and six (9%) patients died. The results of ADCmin, ADCmean, and SUVmax did not show a significant association with progression-free survival (PFS) and overall survival (OS). Significantly shorter PFS was noted in patients with primary tumors with higher MTV (P < 0.001) and TLG (P < 0.001). Significantly shorter OS was also noted in patients with primary tumors with higher MTV (P = 0.048) and TLG (P = 0.034). In the multivariate analysis, MTV was an independent predictor of PFS (hazard ratio = 10.84, P = 0.033). CONCLUSION: PET/MRI biomarkers, particularly MTV and TLG, are associated with PFS and OS in patients with endometrial cancer. MTV was an independent predictor of PFS.

Clinical practice consensus for the diagnosis and management of melanoma in Taiwan.

Melanoma is rare in Taiwan. Asian melanoma is distinct from Western melanoma because acral and mucosal melanoma accounts for the majority of melanoma cases, leading to distinct tumor behaviors and genetic profiling. With consideration of the clinical guidelines in Western countries, Taiwanese experts developed a local clinical practice consensus guideline. This consensus includes diagnosis, staging, and surgical and systemic treatment, based only on clinical evidence, local epidemiology, and available resources evaluated by experts in Taiwan. This consensus emphasizes the importance of surgical management, particularly for sentinel lymph node biopsies. In addition, molecular testing for BRAF is mandatory for patients before systemic treatment. Furthermore, immunotherapy and targeted therapy are prioritized for systemic treatment. This consensus aimed to assist clinicians in Taiwan in diagnosing and treating patients according to available evidence.

In vivo detection of poststroke cerebral cell proliferation in rodents and humans.

OBJECTIVE: F-18-fluorothymidine (FLT) is a positron emission tomography (PET) tracer for imaging cell proliferation in vivo. We aimed to assess FLT uptake as a marker for cerebral cell proliferation in a rat model of ischemic stroke and patients with cerebral infarct, correlating with disease severity and outcomes. METHODS: Cerebral FLT PET was performed in rats subjected to transient middle cerebral artery occlusion (MCAO) and patients with cerebral infarct. PET data were analyzed and expressed as average standardized uptake value ratios (SUVRs) using cerebellar cortex as reference. Infarct volume was analyzed by 2,3,5-triphenyltetrazolium chloride staining in rats and by magnetic resonance imaging in patients. Neurological function was assessed using modified Neurological Severity Score (mNSS) for rats and National Institutes of Health Stroke Scale (NIHSS) for patients. RESULTS: Seven days post-MCAO, rats' FLT PET displayed higher SUVRs in the infarcted brain, declining gradually until Day 28. FLT-binding ratio (SUVR in the infarcted brain divided by that in contralateral side) correlated positively with stroke severity (p < 0.001), and to early mNSS decline in rats with mild to moderate stroke severity (p = 0.031). In 13 patients with cerebral infarct, FLT PET showed high SUVR in the infarcted regions. FLT-binding ratio correlated positively with infarct volume (p = 0.006). Age-adjusted initial NIHSS (p = 0.035) and early NIHSS decline (p = 0.076) showed significance or a trend toward positive correlation with the FLT-binding ratio. INTERPRETATION: In vivo FLT PET detects poststroke cerebral cell proliferation, which is associated with stroke severity and/or outcomes in MCAO rats and patients with cerebral infarct.

Comparison of post-COVID-19 vaccination hypermetabolic lymphadenopathy on 18F-fluorodeoxyglucose PET/CT between virus-vector vaccine and mRNA vaccine.

PURPOSE: We compared hypermetabolic lymphadenopathy (HLN) on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after virus-vector and mRNA vaccines for coronavirus disease 2019 (COVID-19). METHODS: This retrospective study included 573 participants who underwent FDG PET/CT after receiving a virus-vector vaccine (ChAdOx1, AstraZeneca [AZ] group) or an mRNA vaccine (mRNA-1273, Moderna [M] group) from July 2021 to October 2021. The incidence and avidity of HLN were evaluated and correlated with clinical features and vaccine type. The final analysis was conducted with 263 participants in the AZ group and 310 participants in the M group. RESULTS: The HLN incidence was significantly lower in the AZ group than in the M group (38/263 [14%] vs. 74/310 [24%], p = 0.006). The FDG avidity of HLN was comparable between the two groups. The HLN incidence in both groups was significantly higher within 4 weeks after the vaccination compared with more than 4 weeks. The HLN incidence within 4 weeks of the vaccination was significantly higher in the M group than in the AZ group (p = 0.008), whereas a difference in HLN incidence between the two groups was not observed after the same duration (p = 0.11). CONCLUSIONS: The mRNA mRNA-1273 COVID-19 vaccine was found to be associated with higher glucose hypermetabolism in regional lymph nodes within the first 4 weeks compared with the virus-vector vaccine, as indicated by the presence of HLN on FDG PET/CT. The degree of glucose hypermetabolism was comparable between the two vaccines.

Cerebral amyloid deposition predicts long-term cognitive decline in hemorrhagic small vessel disease.

BACKGROUND: To investigate the association between cerebral amyloid deposition and long-term cognitive outcomes in patients with hemorrhagic small vessel disease (SVD) and survivors of intracerebral hemorrhage (ICH). METHODS: Patients experiencing an ICH without overt dementia were prospectively recruited (n = 68) for brain MRI and Pittsburgh compound B (PiB) positron emission tomography scans at baseline. Cognitive function was assessed using the mini-mental status examination (MMSE) and clinical dementia rating after an overall median follow-up of 3.8 years. A positive amyloid scan was defined as a global PiB standardized uptake value ratio >1.2. Associations between follow-up cognitive outcomes and neuroimaging markers were explored using multivariable Cox regression models. RESULTS: PiB(+) patients were older (72.1 ± 7.8 vs. 59.9 ± 11.7, p = .002) and more frequently had cerebral amyloid angiopathy (CAA) (63.6% vs. 15.8%, p = .002) than PiB(-) patients. PiB(+) was associated with a higher risk of dementia conversion (32.9 vs. 4.0 per 100-person-years, hazard ratio [HR] = 15.7 [3.0-80.7], p = .001) and MMSE score decline (58.8 vs. 9.9 per 100-person-years, HR = 6.2 [1.9-20.0], p = .002). In the non-CAA subgroup (n = 52), PiB(+) remained an independent predictor of dementia conversion, p = .04). In the Cox models, PiB(+) was an independent predictor of dementia conversion (HR = 15.8 [2.6-95.4], p = .003) and MMSE score decline (HR = 5.7 [1.6-20.3], p = .008) after adjusting for confounders. CONCLUSIONS: Cerebral amyloid deposition potentially contributes to long-term cognitive decline in SVD-related ICH.

Pretherapy 18F-FDG PET/CT in Predicting Disease Relapse in Patients With Immunoglobulin G4-Related Disease: A Prospective Study.

OBJECTIVE: To investigate whether the levels of inflammation detected by 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) can predict disease relapse in immunoglobulin G4-related disease (IgG4-RD) patients receiving standard induction steroid therapy. MATERIALS AND METHODS: This prospective study analyzed pretherapy FDG PET/CT images from 48 patients (mean age, 63 ± 12.9 years; 45 males and 3 females) diagnosed with IgG4-RD between September 2008 and February 2018, who subsequently received standard induction steroid therapy as the first-line treatment. Multivariable Cox proportional hazards models were used to identify the potential prognostic factors associated with relapse-free survival (RFS). RESULTS: The median follow-up time for the entire cohort was 1913 days (interquartile range [IQR], 803-2929 days). Relapse occurred in 81.3% (39/48) patients during the follow-up period. The median time to relapse was 210 days (IQR, 140-308 days) after completion of standardized induction steroid therapy. Among the 17 parameters analyzed, Cox proportional hazard analysis identified whole-body total lesion glycolysis (WTLG) > 600 on FDG-PET as an independent risk factor for disease relapse (median RFS, 175 vs. 308 days; adjusted hazard ratio, 2.196 [95% confidence interval: 1.080-4.374]; P = 0.030). CONCLUSION: WTLG on pretherapy FDG PET/CT was the only significant factor associated with RFS in IgG-RD patients receiving standard steroid induction therapy.

Myocardial Flow Assessment After Heart Transplantation Using Dynamic Cadmium-Zinc-Telluride Single-Photon Emission Computed Tomography With 201Tl and 99mTc Tracers and Validated by 13N-NH3 Positron Emission Tomography.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is an obliterative and diffuse form of vasculopathy and is the most common cause of long-term cardiovascular mortality in heart transplant patients. This study aimed to investigate the diagnostic performance of 99mTc and 201Tl tracers in the assessment of CAV using cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) for myocardial blood flow (MBF) and myocardial flow reserve (MFR) quantification, which was further validated using 13 N-NH3 positron emission tomography (PET). METHODS: Thirty-eight patients with prior heart transplantation who underwent CZT SPECT and 13 N-NH3 PET dynamic scans were included in this study. CZT SPECT with 99mTc-sestamibi was used in the first 19 patients and 201Tl-chloride for the remaining patients. To determine the diagnostic accuracy of angiographically defined moderate-to-severe CAV, the analysis included patients who underwent angiographic examinations within 1 year of their second scan. RESULTS: There were no significant differences in the patient characteristics between the 201Tl and 99mTc tracer groups. Both 201Tl and 99mTc CZT SPECT-derived stress MBF and MFR values globally and in 3 coronary territories showed good correlations with 13 N-NH3 PET. The 201Tl and 99mTc cohorts did not differ significantly in the correlation coefficients of CZT SPECT versus PET for MBF and MFR, except for stress MBF (201Tl:0.95 versus 99mTc:0.80, P=0.03). 201Tl and 99mTc CZT SPECT were satisfactory for detecting PET MFR <2.0 (201Tl area under the curve, 0.92 [0.71-0.99], 99mTc area under the curve, 0.87 [0.64-0.97]) and angiographically defined moderate-to-severe CAV, and CZT SPECT results were comparable to that of 13 N-NH3 PET (CZT area under the curve, 0.90 [0.70-0.99], PET area under the curve, 0.86 [0.64-0.97]). CONCLUSIONS: This small study suggests that CZT SPECT using 201Tl and 99mTc tracers showed comparable MBF and MFR, and the results correlated well with those of 13 N-NH3 PET. Hence, CZT SPECT with 201Tl or 99mTc tracers can be used to detect moderate-to-severe CAV in patients with prior heart transplantation. However, validation using larger studies is warranted.

Cerebral Venous Reflux and Cerebral Amyloid Angiopathy: An Magnetic Resonance Imaging/Positron Emission Tomography Study.

BACKGROUND: Cerebral venous outflow alterations contribute to central nervous system pathology in aging and neurodegenerative disorders and are potentially linked to underlying cerebral microangiopathy. We investigated whether cerebral venous reflux (CVR) is more closely associated with cerebral amyloid angiopathy (CAA) than hypertensive microangiopathy in intracerebral hemorrhage (ICH) survivors. METHODS: This cross-sectional study included 122 patients of spontaneous ICH with magnetic resonance and positron emission tomography imaging studies (2014-2022) in Taiwan. The presence of CVR was defined as abnormal signal intensity in the dural venous sinus or internal jugular vein on magnetic resonance angiography. Cerebral amyloid load was measured using the Pittsburgh compound B standardized uptake value ratio. Clinical and imaging characteristics associated with CVR were evaluated in univariable and multivariable analyses. In the subset of patients with CAA, we applied univariable and multivariable linear regression analyses to evaluate the association between CVR and cerebral amyloid retention. RESULTS: Compared with patients without CVR (n=84, 64.5±12.1 years), patients with CVR (n=38, 69.4±11.5 years) were significantly more likely to have CAA-ICH (53.7% versus 19.8%; P<0.001) and had a higher cerebral amyloid load (standardized uptake value ratio [interquartile range], 1.28 [1.12-1.60] versus 1.06 [1.00-1.14]; P<0.001). In a multivariable model, CVR was independently associated with CAA-ICH (odds ratio, 4.81 [95% CI, 1.74-13.27]; P=0.002) after adjustment for age, sex and conventional small vessel disease markers. In CAA-ICH, higher PiB retention was observed in patients with CVR than patients without CVR (standardized uptake value ratio [interquartile range], 1.34 [1.08-1.56] versus 1.09 [1.01-1.26]; P<0.001). In multivariable analysis after adjustment for potential confounders, the presence of CVR was independently associated with a higher amyloid load (standardized ß=0.40; P=0.001). CONCLUSIONS: In spontaneous ICH, CVR is associated with CAA and a higher amyloid burden. Our results suggest venous drainage dysfunction potentially plays a role in CAA and cerebral amyloid deposition.

Predicting Treatment Response in Primary Aldosteronism Using 11 C-Metomidate Positron Emission Tomography.

BACKGROUND: Appropriate treatment of primary aldosteronism (PA) depends on accurate lateralization. 11 C-metomidate (MTO) is a tracer used in PET that provides functional information about the adrenal cortex. We aimed to perform MTO PET for patients with PA who are managed according to the guideline and to verify its correlation with other lateralization modalities and usefulness in outcome prediction. METHODS: Seventeen patients with PA who underwent MTO PET and had ≥1 lateralization modality (adrenal venous sampling and/or NP-59 adrenal scintigraphy) were included. SUV max of each adrenal gland (higher uptake side, HSUV max ; lower uptake side, LSUV max ) and the ratio of HSUV max to LSUV max (contrast) were compared with lateralization modalities, postsurgical outcomes, and medical treatment outcomes. Cutoff values were used as outcome predictors. RESULTS: HSUV max and LSUV max increased in the order of bilateral, unilateral, and negative findings of CT, with opposite order of contrast. High discordant rate between MTO PET and other lateralization modalities was noted. Biochemical responders (n = 8) had significantly lower HSUV max and LSUV max than nonresponders, and clinical responders (n = 6) had borderline lower HSUV max than nonresponders. By optimal cutoff values of HSUV max and LSUV max , MTO PET was able to predict biochemical and clinical outcomes in patients with medical treatment. CONCLUSION: According to adrenal CT findings, MTO PET presented different uptake patterns. Patients with PA under medical treatment showed significantly lower tracer uptake in responders. Thus, MTO PET may be a useful imaging biomarker to predict medical treatment outcome. Multicenter prospective study with a larger number of patients is needed for further validation.

Neuroinflammation in Low-Level PM2.5-Exposed Rats Illustrated by PET via an Improved Automated Produced [18F]FEPPA: A Feasibility Study.

Background: [18F]FEPPA is a potent TSPO imaging agent that has been found to be a potential tracer for imaging neuroinflammation. In order to fulfill the demand of this tracer for preclinical and clinical studies, we have developed a one-pot automated synthesis with simplified HPLC purification of this tracer, which was then used for PET imaging of neuroinflammation in fine particulate matter- (PM2.5-) exposed rats. Results: Using this automated synthesis method, the RCY of the [18F]FEPPA was 38 ± 4% (n = 17, EOB) in a synthesis time of 83 ± 8 min from EOB. The radiochemical purity and molar activities were greater than 99% and 209 ± 138 GBq/µmol (EOS, n = 15), respectively. The quality of the [18F]FEPPA synthesized by this method met the U.S. Pharmacopoeia (USP) criteria. The stability test showed that the [18F]FEPPA was stable at 21 ± 2°C for up to 4 hr after the end of synthesis (EOS). Moreover, microPET imaging showed that increased tracer activity of [18F]FEPPA in the brain of PM2.5-exposed rats (n = 6) were higher than that of normal controls (n = 6) and regional-specific. Conclusions: Using the improved semipreparative HPLC purification, [18F]FEPPA has been produced in high quantity, high quality, and high reproducibility and, for the first time, used for PET imaging the effects of PM2.5 in the rat brain. It is ready to be used for imaging inflammation in various clinical or preclinical studies, especially for nearby PET centers without cyclotrons.

[Normal and Near Normal Myocardial Perfusion Imaging Data Analysis: Two-Year Major Adverse Cardiac Event].

BACKGROUND: Myocardial perfusion imaging (MPI) is the method most commonly used to assess patients with suspected coronary artery disease for the presence of myocardial ischemia and risk of subsequent adverse cardiac events. Studies are limited on the incidence of major adverse cardiac event (MACE) in patients with normal MPI results. PURPOSE: The aim of this study was to investigate the incidence and risk factors of MACE in patients with normal or near-normal MPI results. METHODS: In this single-center retrospective chart review study, patients who had received MPI tests at a nuclear medicine department of a medical center in 2017 were consecutively enrolled. All of the participants in this study were patients with normal or near-normal MPI results, and were followed for two years to assess the incidence of MACE (death, hospitalized for percutaneous coronary intervention; CABG, heart failure and stroke). Participants with or without MACE were compared to determine whether demographic, comorbidity, and MPI data were significant risk factors. RESULTS: Of the 1,629 participants (age = 70.4 ± 11.3 years, 49.4% male) enrolled, 387 (23.8%) were classified into the normal MPI group and 1,242 (76.2%) were classified into the near-normal MPI group. Notably, 61 participants (15.8%) in the normal MPI group and 206 (16.6%) in the near-normal MPI group experienced MACE events during the two-year follow-up. The risk factors of MACE identified in this study included being older in age, being male, and having poor myocardial perfusion parameters (i.e., ejection fraction) during MPI. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: Over the two-year study period, 15.8% of the participants with normal MPI results and 16.6% of those with near-normal MPI results experienced major adverse cardiac events. Thus, it is critical to inform patients regarding the potential risk of MACE risk and to educate them on how to mitigate this risk by actively managing their hyperlipidemia level and left ventricular ejection fraction.

Prognostic Value of Interim 18F-DOPA and 18F-FDG PET/CT Findings in Stage 3-4 Pediatric Neuroblastoma.

PURPOSE: This retrospective study aimed to determine the prognostic value of imaging parameters derived from midtherapy 18F-fluorodihydroxyphenylalanine (18F-DOPA) and 18F-FDG PET in pediatric patients with stage 3-4 neuroblastoma. METHODS: We enrolled 32 stage 3-4 pediatric neuroblastoma patients who underwent 18F-DOPA and 18F-FDG PET/CT scans before and after 3 chemotherapy cycles. We measured metabolic and volumetric parameters and applied a metabolic burden scoring system to evaluate the primary tumor extent and soft tissue metastases and that of bone/bone marrow involvement. The associations between these parameters and clinical outcomes were investigated. RESULTS: Over a median follow-up period of 47 months (range, 3-137 months), 16 patients experienced disease progression, and 13 died. After adjustment for clinical factors, multivariate Cox proportional hazard models showed that interim tumor FDG/FDOPA SUVmax (hazard ratio [HR], 5.94; 95% confidence interval [CI], 1.10-34.98) and interim FDOPA whole-body metabolic burden scores (WBMB) (HR, 7.30; 95% CI, 1.50-35.50) were significant prognostic factors for overall survival (OS). Only interim FDOPA WBMB scores (HR, 7.05; 95% CI, 1.02-48.7) were predictive of progression-free survival. Based on median cutoff values, prognosis (OS and progression-free survival) was significantly associated with an interim FDOPA WBMB score ≥21.92 (all P < 0.05) and interim tumor FDG/FDOPA (SUVmax) score ≥0.57 with poor OS (P < 0.05). CONCLUSIONS: Our results indicate that midtreatment FDG and FDOPA PET/CT could serve as prognostic markers in stage 3-4 neuroblastoma patients.

Diagnostic Performance of Proton Magnetic Resonance Spectroscopy and 18F-Fluorocholine PET to Differentiate Benign From Malignant Breast Lesions.

PURPOSE: The aim of this study was to evaluate the diagnostic performance of the proton magnetic resonance spectroscopy (MRS) and 18F-fluorocholine (FCH) PET for suspicious breast findings on conventional imaging (mammography and breast ultrasound). METHODS: From September 2012 to December 2015, 37 women with 39 breast lesions on conventional imaging were enrolled and underwent proton MRS and FCH PET. The MRS parameters of choline signal-to-noise ratio (SNR), choline integral (I(cho)), and the PET parameters including SUVmax in the prone (SUV1) and supine (SUV2) positions were analyzed. Receiver operating characteristic curves with the area under the curve, sensitivity, and specificity under the optimal cutoff points for the different parameters were determined. RESULTS: Twenty-three lesions (59%) were malignant, and 16 (41.0%) were benign. The malignant lesions tended to show significantly higher MRS and PET parameters than benign lesions (choline SNR, P = 0.007; I(cho), P = 0.003; SUV1 and SUV2, P < 0.0001). Fair to moderate correlations were noted between the choline SNR and PET parameters (SUV1, Spearman rank correlation coefficient, ρ = 0.477; SUV2, ρ = 0.483), as well as I(cho) and PET parameters (SUV1, ρ = 0.493; SUV2, ρ = 0.549). The SUV2 showed the highest diagnostic performance (area under the curve, 0.918). Using 2.5 as the optimal cutoff point, the SUV2 yields 89.5% sensitivity and 87.5% specificity for differentiating malignant from benign lesions. CONCLUSION: The MRS parameters were fairly to moderately correlated with FCH PET parameters, and both could differentiate malignant from benign breast lesions with SUV2 showing best diagnostic performance.

Factors predicting one or two sentinel lymph nodes to be accepted for sentinel lymph node biopsy alone after neoadjuvant therapy in initially node-positive breast cancer patients.

BACKGROUND: Current guidelines recommend harvesting ≥3 sentinel nodes if sentinel lymph node biopsy (SLNB) alone is considered after neoadjuvant therapy (NAT) for initially node-positive (cN+) breast cancer. We attempted to investigate factors predicting one or two sentinel lymph nodes harvested to be accepted for SLNB alone after NAT in initially cN + patients. METHODS: Overall, 157 patients who received NAT (clinically T1-3/N1-2/M0) and underwent SLNB were identified from a prospectively maintained database. Significant factors were identified using a multiple logistic regression model. RESULTS: The overall SLN identification rate was 83.4%. Failed SLN identification was associated with a 2-day protocol using a single tracer (odds ratio: 0.331 [95% confidence interval {CI}: 0.132-0.830], p = 0.018), age >52 years (0.345 [0.131-0.913], p = 0.032), and lobular histology (0.156 [0.026-0.944], p = 0.043). The overall false-negative SLNB rate was 14.7%. Its increased risk was associated with radioactivity count >530 for any SLN during SLNB (96.4 [4.00-2320], p = 0.005), age ≥57 years (34.2 [1.92-610], p = 0.016), and taxane use (105 [1.02-10700], p = 0.049); its decreased risk was associated with more harvested SLNs (0.191 [0.054-0.669], p = 0.01) and dual tracers (0.101 [0.012-0.843], p = 0.034). A predictive model using these factors achieved an area under the curve of 0.935 (95% CI: 0.878-0.991). CONCLUSION: When taxane was administered during NAT, the false-negative rate was predicted at <5% for patients aged <57 years, if 1-2 SLNs were harvested using dual tracers, and when the count of every SLN was lower than 530 after NAT in cN + breast cancer.

Diagnostic Effect of Attenuation Correction in Myocardial Perfusion Imaging in Different Coronary Arteries: A Systematic Review and Meta-Analysis.

Background: The aim of this study was to determine whether, and if so how, attenuation correction (AC) improves the diagnostic performance of myocardial perfusion imaging (MPI) in different coronary artery-supplied territories, using coronary angiography as the reference standard. Methods: PubMed and EMBASE were searched until December 2020 for studies evaluating AC MPI for the diagnosis of coronary artery disease (CAD) with vessel-based data. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. For each study, the sensitivity, specificity, diagnostic odds ratios and areas under summary receiver operating characteristic curves (AUC) with 95% confidence intervals were calculated to determine the diagnostic accuracy of AC compared to non-AC MPI. A bivariate mixed-effects model was used to pool the data. Subgroup analyses considering the type of radiotracer and type of AC were performed. Results: A total of 264 articles were screened, of which 22 studies (2,608 patients) were enrolled. Significant improvements in specificity [0.78 vs. 0.58 in overall CAD, 0.87 vs. 0.61 in right coronary artery (RCA)] and diagnostic odds ratios (16 vs. 8 in overall CAD, 18 vs. 7 in RCA) after AC were shown in overall CAD at a patient level and RCA stenosis. Improvements in AUC were also noted. MPI had a similar diagnostic performance for detecting left anterior descending and left circumflex coronary artery stenosis with or without AC. There were trends of decreased sensitivity after AC, but none were significant. Diagnostic odds ratio showed significant improvement after AC only in the technetium-99m subgroup. Conclusion: The results of this study suggest that AC should be applied to MPI to improve the diagnosis of CAD regardless of which type of radiotracer, and that AC MPI can improve the specificity of detecting RCA stenosis.

Long-term prognostic value of computed tomography-based attenuation correction on thallium-201 myocardial perfusion imaging: A cohort study.

BACKGROUND: Myocardial perfusion imaging (MPI) is a well-established diagnostic tool to evaluate coronary artery disease (CAD) and also an effective prognostic tool for patients with CAD. However, few studies investigated the prognostic value of attenuation correction (AC) in MPI, and the results were controversial. OBJECTIVES: To investigate the prognostic value of computed tomography (CT)-based AC thallium-201 (Tl-201) MPI. METHODS: A total of 108 consecutive patients who underwent Tl-201 MPI and received coronary angiography within 90 days were included. Medical records were reviewed and missing information was completed after telephone contact. The prognostic value was evaluated by Kaplan-Meier analysis, univariable and multivariable Cox proportional hazards model. RESULTS: After a mean follow-up of 7.72 ± 3.72 years, 27 patients had died, 41 had been readmitted for cardiovascular (CV)-related events and 44 had reached the composite of death plus CV-related re-admission. Kaplan-Meier curves for all-cause mortality for SSS with a cutoff value of 13 for AC and 16 for non-AC (NAC) images showed a significant difference between the two curves for both AC and NAC images (p = 0.011 for AC and p = 0.021 for NAC). In the multivariable model, SSS and SRS showed similar independent predictive values in predicting all-cause mortality and composite of all-cause mortality plus CV-related re-admission, in both AC and NAC images. Subgroup analysis implicated that AC MPI possibly provided better risk stratification in obese patients. CONCLUSION: CT-based AC and NAC MPI showed similar value and were the only significant predictors for the composite of mortality and CV events.

Plasma soluble TREM2 is associated with white matter lesions independent of amyloid and tau.

Cerebral small vessel disease is one of the most common causes of cognitive decline and stroke. While several lines of evidence have established a relationship between inflammation and cerebrovascular pathology, the mechanistic link has not yet been elucidated. Recent studies suggest activation of immune mediators, including the soluble form of triggering receptor expressed on myeloid cells 2 (TREM2), may be critical regulators. In this study, we compared the plasma levels of soluble TREM2 and its correlations with neuroimaging markers and cerebral amyloid load in 10 patients with Alzheimer's disease and 66 survivors of spontaneous intracerebral haemorrhage with cerebral amyloid angiopathy or hypertensive small vessel disease, two of the most common types of sporadic small vessel disease. We performed brain MRI and 11C-Pittsburgh compound B PET for all participants to evaluate radiological small vessel disease markers and cerebral amyloid burden, and 18F-T807 PET in a subgroup of patients to evaluate cortical tau pathology. Plasma soluble TREM2 levels were comparable between patients with Alzheimer's disease and small vessel disease (P = 0.690). In patients with small vessel disease, plasma soluble TREM2 was significantly associated with white matter hyperintensity volume (P < 0.001), but not with cerebral amyloid load. Among patients with Alzheimer's disease and cerebral amyloid angiopathy, plasma soluble TREM2 was independently associated with a tau-positive scan (P = 0.001) and white matter hyperintensity volume (P = 0.013), but not amyloid load (P = 0.221). Our results indicate plasma soluble TREM2 is associated with white matter hyperintensity independent of amyloid and tau pathology. These findings highlight the potential utility of plasma soluble TREM2 as a strong predictive marker for small vessel disease-related white matter injury and hold clinical implications for targeting the innate immune response when treating this disease.

2021 Advocacy Statements for the Role of 99mTc-Pyrophosphate Scintigraphy in the Diagnosis of Transthyretin Cardiac Amyloidosis: A Report of the Taiwan Society of Cardiology and the Society of Nuclear Medicine of the Republic of China.

Transthyretin cardiac amyloidosis (ATTR-CM) is an increasingly recognized cause of heart failure with preserved ejection fraction. Favorable prognosis depends on early diagnosis and correct treatment strategy. Among patients for whom there is a high clinical suspicion of cardiac amyloidosis, 99mTc-labeled bone avid scintigraphy including 99mTc-pyrophosphate (PYP) scintigraphy may be of diagnostic and prognostic importance. Various international guidelines support the non-biopsy diagnosis of ATTR-CM using 99mTc-PYP scintigraphy, yet emphasize the gap in standardization of acquisition and imaging analysis protocols, as well as the appropriateness of its clinical use. Therefore, a joint expert consensus has been reached by the Taiwan Society of Cardiology and the Society of Nuclear Medicine of the Republic of China, to advocate for the application of 99mTc-PYP scintigraphy in the diagnosis of ATTR-CM. This article aims to highlight the recommendations on image acquisition, qualitative and quantitative assessments of cardiac 99mTc-PYP uptake, and diagnostic algorithms. We hope the implementation of these recommendations in Taiwan will facilitate the process and enhance the diagnostic rate of ATTR-CM.