Impact of patient characteristic factors on the dynamics of liver glucose metabolism: Evaluation of multiparametric imaging with dynamic whole-body 18F-fluorodeoxyglucose-positron emission tomography

Aims

To assess the impact of various patient characteristics on the dynamics of liver glucose metabolism using automated multiparametric imaging with whole-body dynamic ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET).

Materials and Methods

We retrospectively enrolled 540 patients who underwent whole-body dynamic FDG-PET. Three quantitative indices representing hepatic glucose metabolism [mean standardized uptake value normalized by lean body mass (SULmean), metabolic glucose rate (kinetic index) and distribution volume (DV)] were measured from multiparametric PET images produced automatically based on the Patlak plot model. Patient characteristics including age, sex, body mass index, fasting time, blood glucose level, and the presence of diabetes mellitus (DM) or hepatic steatosis (HS) were collected. We examined the correlations between the characteristic factors and three quantitative indices using multiple regression analysis.

Results

The success rate of kinetic analysis using multiparametric PET imaging was 93.3% (504/540). Hepatic SULmean was significantly correlated with age (p < .001), sex (p < .001) and blood glucose level (p = .002). DV was significantly correlated with age (p = .033), sex (p < .001), body mass index (p = .002), fasting time (p = .043) and the presence of HS (p = .002). The kinetic index was significantly correlated with age (p < .001) and sex (p = .004). In the comparison of the healthy, DM and HS groups, patients with DM had a significantly increased SULmean, whereas patients with HS had a significantly decreased DV.

Conclusions

Our results showed that liver glucose metabolism was influenced by various patient characteristic factors. Multiparametric FDG-PET imaging can be used to analyse the kinetics of liver glucose metabolism in routine clinical practice.     

The burden of disease of dental anxiety: generic and disease‐specific quality of life in patients with and without extreme levels of dental anxiety

The aim of this study was to compare disease‐specific (oral health‐related) quality of life (OHRQoL), assessed using the Oral Health Impact Profile‐14 (OHIP‐14), and generic (health‐related) quality of life (HRQoL), assessed using the EuroQol5D (EQ‐5D‐5L), in patients with severe dental anxiety (who were visiting a centre for special care dentistry) with a control group from the general population. Seventy‐six patients with severe dental anxiety [Dental Anxiety Scale (DAS) score ≥ 13] were matched, according to age, gender, and socio‐economic status, to a control group of 76 participants in a larger epidemiological study on oral health in the Netherlands (n = 1,125). The Wilcoxon signed‐rank test was used to compare levels of HRQoL and OHRQoL in both groups. The total OHIP score (indicating lower OHRQoL) was higher for the patient group (10th percentile = 30.5; 90th percentile = 46.0) than for the control group (10th percentile = 1.0; 90th percentile = 14.5). The patient group showed higher scores on all seven OHIP domains. Lower utility scores were found in patients with severe dental anxiety (HRQOL: 10th percentile = 0.7; 90th percentile = 0.9) relative to the control group (HRQOL: 10th percentile = 0.9; 90th percentile = 1.0). A disease burden of 74,000 disability‐adjusted life years (DALYs) was calculated for the Netherlands. The findings of this study show differences between patients visiting a dental fear clinic and matched controls from the general population for both OHRQoL and HRQoL, indicating that having severe dental anxiety generates a significant burden of disease.     

Doppler velocimetry determined redistribution of fetal blood flow: Correlation with growth restriction in diamniotic monochorionic and dizygotic twins

OBJECTIVE: Our purpose was to study fetal growth and blood flow distribution in diamniotic monochorionic compared with dizygotic (diamniotic dichorionic) twins by use of Doppler velocimetry of the umbilical artery and middle cerebral artery. STUDY DESIGN: Study candidates were divided into group A, consisting of 33 pairs (66 fetuses) of diamniotic monochorionic twins, and group B, 50 pairs (100 fetuses) of diamniotic dichorionic twins. Diamniotic monochorionic placentation was confirmed by microscopic placental examination for group A. Diamniotic dichorionic placentation was ensured for group B by selecting only twins with different-sex pairs (dizygotic twins). Targeted ultrasonography with biometry was performed in each twin, and Doppler recordings of the umbilical artery and middle cerebral artery were obtained. Waveforms were analyzed and the systolic/diastolic ratio, the resistance index, and a measure of blood flow redistribution (brain-sparing effect), the cerebral/placental ratio, was calculated for each fetus. Growth status at birth was assessed by the number of small-for-gestational-age infants (≤10th percentile), low-birth-weight infants (≤25th percentile), and percent of growth discordance between twins. Intertwin differences were assessed by Δ values (value of larger twin minus value of smaller twin). RESULTS: Diamniotic monochorionic compared with dizygotic twins demonstrated a significantly greater probability of blood flow redistribution. For the study population as a whole, the brain-sparing effect was noted in 67% of small-for-gestational-age babies and only 7% of non-small-for-gestational-age infants (p ≤ 0.001). For the diamniotic monochorionic pregnancies blood flow redistribution occurred in 6 of 10 small-for-gestational-age infants (60%) and 6 of 46 non-small-for-gestational-age infants (13%). In the diamniotic monochorionic group small-for-gestational-age compared with non-small-for-gestational-age infants were more likely to show blood flow redistribution, which was the result of significantly decreased resistance in the middle cerebral artery and significantly increased resistance in the umbilical artery. Small-for-gestational-age infants (≤10th percentile) occurred much less frequently in the dizygotic group. Two of two small-for-gestational-age infants in the dizygotic group showed blood flow redistribution. Although the extremes of birth weight were more common in the diamniotic monochorionic group, both groups had relatively large numbers of small babies with birth weights in the lower 25th percentile (50.0% for diamniotic monochorionic and 44.0% for dizygotic twins, not significant). However, 42.3% (11/26) of diamniotic monochorionic twins who were in the low-birth-weight group showed blood flow redistribution compared with only 3.3% (1/30) whose birth weights were ≥25th percentile (p ≤ 0.001). In the dizygotic twins 10% of lower-birth-weight infants redistributed blood flow compared with 1% in the higher-birth-weight group, a nonsignificant difference. Diamniotic monochorionic compared with dizygotic twins were delivered earlier (32.9 weeks vs 34.8 weeks, p ≤ 0.001), were smaller (1832 gm vs 2304 gm, p ≤ 0.001), showed higher birth weight discordance (29.8% vs 14%, p ≤ 0.05), and had greater numbers (19.7% vs 2.3%, p ≤ 0.01) of infants at ≤10th percentile birth weight. CONCLUSIONS: Diamniotic monochorionic twins from the lower-birth-weight groups more often show blood flow redistribution compared with dizygotic twins of similar low birth weights. Placental vascular connections and the attendant hemodynamic changes in the fetuses of diamniotic monochorionic twins probably account for this difference. Brain-sparing events occur commonly without clinical twin transfusion syndrome in this group. These findings have implications for management. (Am J Obstet Gynecol 1998;178:1359-67.)     

An improved method for estimating the heart-to-mediastinum ratio from cardiac sympathetic nerve imaging with low-energy high-resolution collimators

Background

Septal penetration causes underestimation of the heart-to-mediastinum (H/M) ratio in cardiac ¹²³I-metaiodobenzylguanidine (MIBG) imaging with a low-energy high-resolution (LEHR) collimator. We aimed to improve the method of estimating the H/M ratios using the LEHR collimator.

Methods and Results

4 hours after ¹²³I-MIBG injection, 40 patients were imaged successively with the medium-energy (ME) and LEHR collimators using gamma cameras having 3/8-inch crystals. Severe underestimation of the H/M ratios was observed with the LEHR collimator when compared to the ME collimator. Narrowing the energy window width did not reduce the underestimation. Application of ¹²³I-dual-window (IDW) correction using a narrow or wide subwindow reduced the underestimation substantially but not entirely. The H/M ratios estimated from the LEHR images with or without IDW correction were corrected based on their correlations with the ratios estimated from the ME images. This empiric correction removed systematic underestimation, and residual errors were reduced when the H/M ratios after IDW correction were converted using the empiric equation. The conversion equation was successfully applied to the correction of the H/M ratios determined in another 40 patients using a 5/8-inch crystal.

Conclusions

In estimating the H/M ratios using an LEHR collimator, empiric correction combined with IDW correction improves concordance with ME-based values in comparison with empiric correction alone.     

Vascular compression of the oculomotor nerve disclosed by thin-slice magnetic resonance imaging

Purpose: To describe the thin-slice magnetic resonance imaging features of vascular compressive oculomotor nerve paresis.Methods: We performed thin-slice (2 mm thick) magnetic resonance imaging of the brainstem in a 74-year-old woman with right partial oculomotor nerve paresis using spoiled gradient recalled acquisition in the steady state.Results: Thin-slice magnetic resonance images disclosed that the right oculomotor nerve was compressed and dislocated superiorly and laterally by the tortuous basilar artery. No other abnormalities were observed.Conclusion: This is the first case report of vascular compressive oculomotor nerve paresis disclosed by thin-slice magnetic resonance imaging.