18 FTHK-5351 PET Patterns in Patients With Alzheimer’s Disease and Negative Amyloid PET Findings

Background@#and Purpose Alzheimer’s disease (AD) does not always mean amyloid positivity. [ 18 F]THK-5351 has been shown to be able to detect reactive astrogliosis as well as tau accompanied by neurodegenerative changes. We evaluated the [ 18 F]THK-5351 retention patterns in positron-emission tomography (PET) and the clinical characteristics of patients clinically diagnosed with AD dementia who had negative amyloid PET findings. @*Methods@#We performed 3.0-T magnetic resonance imaging, [ 18 F]THK-5351 PET, and amyloid PET in 164 patients with AD dementia. Amyloid PET was visually scored as positive or negative. [ 18 F]THK-5351 PET were visually classified as having an intratemporal or extratemporal spread pattern. @*Results@#The 164 patients included 23 (14.0%) who were amyloid-negative (age 74.9±8.3 years, mean±standard deviation; 9 males, 14 females). Amyloid-negative patients were older, had a higher prevalence of diabetes mellitus, and had better visuospatial and memory functions. The frequency of the apolipoprotein E ε4 allele was higher and the hippocampal volume was smaller in amyloid-positive patients. [ 18 F]THK-5351 uptake patterns of the amyloid-negative patients were classified into intratemporal spread (n=10) and extratemporal spread (n=13).Neuropsychological test results did not differ significantly between these two groups. The standardized uptake value ratio of [ 18 F]THK-5351 was higher in the extratemporal spread group (2.01±0.26 vs. 1.61±0.15, p=0.001). After 1 year, Mini Mental State Examination (MMSE) scores decreased significantly in the extratemporal spread group (-3.5±3.2, p=0.006) but not in the intratemporal spread group (-0.5±2.8, p=0.916). The diagnosis remained as AD (n=5, 50%) or changed to other diagnoses (n=5, 50%) in the intratemporal group, whereas it remained as AD (n=8, 61.5%) or changed to frontotemporal dementia (n=4, 30.8%) and other diagnoses (n=1, 7.7%) in the extratemporal spread group. @*Conclusions@#Approximately 70% of the patients with amyloid-negative AD showed abnormal [ 18 F]THK-5351 retention. MMSE scores deteriorated rapidly in the patients with an extratemporal spread pattern.

18F-THK5351 PET Positivity and Longitudinal Changes in Cognitive Function in β-Amyloid-Negative Amnestic Mild Cognitive Impairment

Purpose@#Neuroinflammation is considered an important pathway associated with several diseases that result in cognitive decline. 18F-THK5351 positron emission tomography (PET) signals might indicate the presence of neuroinflammation, as well as Alzheimer’s disease-type tau aggregates. β-amyloid (Aβ)-negative (Aβ–) amnestic mild cognitive impairment (aMCI) may be associated with non-Alzheimer’s disease pathophysiology. Accordingly, we investigated associations between 18F-THK5351 PET positivity and cognitive decline among Aβ– aMCI patients. @*Materials and Methods@#The present study included 25 amyloid PET negative aMCI patients who underwent a minimum of two follow-up neuropsychological evaluations, including clinical dementia rating-sum of boxes (CDR-SOB). The patients were classified into two groups: 18F-THK5351-positive and -negative groups. The present study used a linear mixed effects model to estimate the effects of 18F-THK5351 PET positivity on cognitive prognosis among Aβ– aMCI patients. @*Results@#Among the 25 Aβ– aMCI patients, 10 (40.0%) were 18F-THK5351 positive. The patients in the 18F-THK5351-positive group were older than those in the 18F-THK5351-negative group (77.4±2.2 years vs. 70.0±5.5 years; p<0.001). There was no difference between the two groups with regard to the proportion of apolipoprotein E ε4 carriers. Interestingly, however, the CDR-SOB scores of the 18F-THK5351-positive group deteriorated at a faster rate than those of the 18F-THK5351-negative group (B=0.003, p=0.033). @*Conclusion@#The results of the present study suggest that increased 18F-THK5351 uptake might be a useful predictor of poor prognosis among Aβ– aMCI patients, which might be associated with increased neuroinflammation (ClinicalTrials.gov NCT02656498).

The Characteristics of Women with Subsequent Distal Radius Fracture after Initial Distal Radius Fracture

Background@#The purpose of this study was to investigate the characteristics of women with subsequent distal radius fracture (DRF) and to compare bone fragility variables in women with initial and subsequent DRF. @*Methods@#We enrolled 227 women who experienced DRF (203 women with initial DRF and 24 women with subsequent DRF) between September 2016 and April 2019. We compared demographic characteristics and bone fragility variables, including bone mineral density, trabecular bone score, hip geometry, bicortical thickness of the distal radius, and fracture risk assessment tool (FRAX) scores between the 2 groups. To reduce bias, patients with subsequent DRF were propensity score-matched in a 1:2 manner with patients affected by initial DRF, and additional comparisons were performed. @*Results@#Patients in the subsequent DRF group were older than those in the initial DRF group, but this difference was not significant (P=0.091). The proportion of patients receiving treatment with osteoporosis medication was significantly higher in the subsequent DRF group (41.7% vs. 19.2%, P=0.011). Bone fragility variables did not differ significantly between the 2 groups. However, the ten-year probability of major osteoporotic fractures based on FRAX scores was significantly higher in patients with subsequent DRF (7.5% vs. 10.8%, P<0.001). Similar results were observed when comparing the propensity score-matched initial and subsequent DRF groups. @*Conclusions@#These findings suggest that the occurrence of subsequent DRF after initial DRF can be attributed to multiple factors rather than bone fragility alone. Systematic and multidisciplinary management would be helpful in preventing the occurrence of subsequent DRF after the initial DRF.

The Characteristics of Women with Subsequent Distal Radius Fracture after Initial Distal Radius Fracture

Background@#The purpose of this study was to investigate the characteristics of women with subsequent distal radius fracture (DRF) and to compare bone fragility variables in women with initial and subsequent DRF. @*Methods@#We enrolled 227 women who experienced DRF (203 women with initial DRF and 24 women with subsequent DRF) between September 2016 and April 2019. We compared demographic characteristics and bone fragility variables, including bone mineral density, trabecular bone score, hip geometry, bicortical thickness of the distal radius, and fracture risk assessment tool (FRAX) scores between the 2 groups. To reduce bias, patients with subsequent DRF were propensity score-matched in a 1:2 manner with patients affected by initial DRF, and additional comparisons were performed. @*Results@#Patients in the subsequent DRF group were older than those in the initial DRF group, but this difference was not significant (P=0.091). The proportion of patients receiving treatment with osteoporosis medication was significantly higher in the subsequent DRF group (41.7% vs. 19.2%, P=0.011). Bone fragility variables did not differ significantly between the 2 groups. However, the ten-year probability of major osteoporotic fractures based on FRAX scores was significantly higher in patients with subsequent DRF (7.5% vs. 10.8%, P<0.001). Similar results were observed when comparing the propensity score-matched initial and subsequent DRF groups. @*Conclusions@#These findings suggest that the occurrence of subsequent DRF after initial DRF can be attributed to multiple factors rather than bone fragility alone. Systematic and multidisciplinary management would be helpful in preventing the occurrence of subsequent DRF after the initial DRF.

A 4-Year Follow-Up of Subjects with Visually Equivocal Amyloid Positron Emission Tomography Findings from the Alzheimer’s Disease Neuroimaging Initiative Cohort / 대한핵의학회잡지

Background@#To date, the clinical significance of visually equivocal amyloid positron emission tomography (PET) has not been well established. @*Objective@#We studied the clinical significance of equivocal amyloid PET images from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). @*Methods@#Subjects with F-18 florbetapir PET scans at baseline who were followed up for 4 years were selected. Clinical characteristics, imaging biomarkers, cognitive function, and rate of conversion to AD were compared in subjects with visually equivocal findings. @*Results@#Of 249 subjects who completed the follow-up, 153 (61.4%), 20 (8.0%), and 129 (30.5%) were F-18 florbetapir-negative, -equivocal, and -positive, respectively. The mean standardized uptake value ratios (SUVR) of F-18 florbetapir PET were 0.75 ± 0.04, 0.85 ± 0.10, and 1.00 ± 0.09 for each group (p <0.001 between groups), and 15.0%, 70.0%, and 98.7% of patients were quantitatively above the positive threshold. The change in the SUVR of F-18 florbetapir PET was higher in the equivocal (6.09 ± 3.61%, p <0.001) and positive (3.13 ± 4.38%, p <0.001) groups than the negative group (0.88 ± 4.28%). Among the subjects with normal or subjective memory impairment and mild cognitive impairment, 5.3% with negative amyloid PET and 37.5% with positive amyloid PET converted to AD over the 4-year period. None of the equivocal amyloid PET subjects converted to AD during this period.

False-negative Hepatobiliary Scintigraphy for Biliary Atresia / 대한핵의학회잡지

We present the case of a patient with biliary and duodenal atresia who showed false-negative hepatobiliary scintigraphy results. The patient was born at 37 weeks and 2 days of gestation. Her mother had undergone amnioreduction after detection of a double-bubble ultrasound sign in the fetal abdomen. At 2 days of age, total serum bilirubin level was elevated. On hepatobiliary scintigraphy 4 days later, the gallbladder was visualized from 30 min and it showed duodeno-gastric reflux at 240 min. After 24 h, the radiotracer was almost washed out in the hepatic parenchyma, but there was retention in the gastroduodenal junction. Because the biliary to duodenal transit was visible, biliary atresia seemed unlikely. Abdominal ultrasonography at 7 days of age showed a small dysmorphic gallbladder, but triangular cord sign was not definite. Magnetic resonance cholangiography revealed atretic gallbladder. Although cystic and common bile ducts were visible, the proximal common hepatic bile duct was not visible. The next day, serum total bilirubin levels remained elevated (17.1 mg/dl) with direct bilirubin level of 1.2 mg/dl. Kasai portoenterostomy with duodeno-duodenostomy was performed at 10 days of age. Histopathological evaluation showed a fibrous obliteration of the common bile duct, consistent with that of biliary atresia.

False-negative Hepatobiliary Scintigraphy for Biliary Atresia / 대한핵의학회잡지

We present the case of a patient with biliary and duodenal atresia who showed false-negative hepatobiliary scintigraphy results. The patient was born at 37 weeks and 2 days of gestation. Her mother had undergone amnioreduction after detection of a double-bubble ultrasound sign in the fetal abdomen. At 2 days of age, total serum bilirubin level was elevated. On hepatobiliary scintigraphy 4 days later, the gallbladder was visualized from 30 min and it showed duodeno-gastric reflux at 240 min. After 24 h, the radiotracer was almost washed out in the hepatic parenchyma, but there was retention in the gastroduodenal junction. Because the biliary to duodenal transit was visible, biliary atresia seemed unlikely. Abdominal ultrasonography at 7 days of age showed a small dysmorphic gallbladder, but triangular cord sign was not definite. Magnetic resonance cholangiography revealed atretic gallbladder. Although cystic and common bile ducts were visible, the proximal common hepatic bile duct was not visible. The next day, serum total bilirubin levels remained elevated (17.1 mg/dl) with direct bilirubin level of 1.2 mg/dl. Kasai portoenterostomy with duodeno-duodenostomy was performed at 10 days of age. Histopathological evaluation showed a fibrous obliteration of the common bile duct, consistent with that of biliary atresia.

Longitudinal Decline of Striatal Subregional ¹⁸FFP-CIT Uptake in Parkinson's Disease / 대한핵의학회잡지

PURPOSE: Dopamine transporter imaging is suggested to be a useful imaging biomarker for Parkinson's disease (PD) progression and monitoring drug effects.We investigated the longitudinal decline characteristics of striatal [¹⁸F]FP-CIT uptake in PD.METHODS: We retrospectively reviewed 35 PD patients and 9 non-PD patients. All patients underwent [¹⁸F]FP-CIT PET at the initial diagnosis and follow-up. PET images were spatially normalized and analyzed with eight striatal and one occipital VOI templates. We measured the specific to non-specific binding ratio (SNBR) of the striatal subregions and calculated the absolute annual reduction (AAR) and relative annual reduction (%RAR) of the SNBRs.RESULTS: Total striatal SNBRs in PD patients were significantly lower than those in non-PD patients, with the most significant difference in the posterior putamen. Both AAR (0.26 ± 0.14 vs. 0.09 ± 0.19, p < 0.05) and %RAR (6.9 ± 3.5 vs. 1.2 ± 2.7, p < 0.001) of total striatal SNBRs were significantly greater in PD than non-PD patients. There were no significant differences in the AAR and %RAR of total striatal SNBRs between elderly and young onset PD. The AARs of the posterior putamen were higher in early PD than in advanced PD. Conversely, the %RARs were not significantly different between early and more advanced PD. The disease duration was significantly negatively correlated with the AAR but not with the %RAR of the posterior putamen.CONCLUSIONS: The longitudinal decline of striatal [¹⁸F]FP-CIT uptake in PD was nonlinear and significantly faster than that in non-PD, with a different rate of decline among the striatal subregions.

Altered Biodistribution of (99m)Tc-DPD on Bone Scan After Intravenous Iron Supplement / 대한핵의학회잡지

We report a casewith altered biodistribution of (99m)Tc-dicarboxypropane diphosphonate ((99m)Tc-DPD) on whole body bone scan after intravenous iron supplement therapy. A 47-year-old male patient who had recently been detected with a hepatic mass suggestive of hepatocellular carcinoma underwent bone scan as staging work-up before surgery. Bone scan images at 3 h after injection of (99m)Tc-DPD demonstrated unusually increased blood pool activities in the heart, liver, and spleen with usual skeletal uptakes. The patient had been treated for severe anemia from hemorrhoid with two intravenous administration of ferric hydroxide carboxymaltose complex at approximately 22 h and 2 h prior to the (99m)Tc-DPD injection, which we consider as themost probable cause of altered biodistribution of (99m)Tc-DPD.

Risk Stratification for Avascular Necrosis of the Femoral Head After Internal Fixation of Femoral Neck Fractures by Post-Operative Bone SPECT/CT / 대한핵의학회잡지

PURPOSE: Avascular necrosis (AVN) of the femoral head is a major complication after internal fixation of a femoral neck fracture and determines the functional prognosis. We investigated postoperative bone single-photon emission computed tomography/computed tomography (SPECT/CT) for assessing the risk of femoral head AVN.METHODS: We retrospectively reviewed 53 consecutive patients who underwent bone SPECT/CT within 2 weeks of internal fixation of a femoral neck fracture and follow-up serial hip radiographs over at least 12 months.RESULTS: Nine patients developed femoral head AVN. In 15 patients who showed normal uptake on immediate postoperative SPECT/CT, no AVN occurred, whereas 9 of 38 patients who showed cold defects of the femoral head later developed AVN. The negative predictive value of immediate postoperative SPECT/CT for AVN was 100 %, whereas the positive predictive value was 24 %. Among 38 patients with cold defects, 1 developed AVN 3 months postoperatively. A follow-up bone SPECT/CT was performed in the other 37 patients at 2??0 months postoperatively. The follow-up bone SPECT/CT revealed completely normalized femoral head uptake in 27, partially normalized uptake in 8, and persistent cold defects in 2 patients. AVN developed in 3.7 % (1/27), 62.5 % (5/8), and 100 % (2/2) of each group, respectively.CONCLUSION: According to the time point of imaging, radiotracer uptake patterns of the femoral head on postoperative bone SPECT/CT indicate the risk of AVN after internal fixation of femoral neck fractures differently. Postoperative bone SPECT/CT may help orthopedic surgeons determine the appropriate follow-up of these patients.