Clinical Feasibility of Deep Learning-Based Attenuation Correction Models for Tl-201 Myocardial Perfusion SPECT

PURPOSE

We aimed to develop deep learning (DL)-based attenuation correction models for Tl-201 myocardial perfusion SPECT (MPS) images and evaluate their clinical feasibility.

PATIENTS AND METHODS

We conducted a retrospective study of patients with suspected or known coronary artery disease. We proposed a DL-based image-to-image translation technique to transform non-attenuation-corrected images into CT-based attenuation-corrected (CT AC ) images. The model was trained using a modified U-Net with structural similarity index (SSIM) loss and mean squared error (MSE) loss and compared with other models. Segment-wise analysis using a polar map and visual assessment for the generated attenuation-corrected (GEN AC ) images were also performed to evaluate clinical feasibility.

RESULTS

This study comprised 657 men and 328 women (age, 65 ± 11 years). Among the various models, the modified U-Net achieved the highest performance with an average mean absolute error of 0.003, an SSIM of 0.990, and a peak signal-to-noise ratio of 33.658. The performance of the model was not different between the stress and rest datasets. In the segment-wise analysis, the myocardial perfusion of the inferior wall was significantly higher in GEN AC images than in the non-attenuation-corrected images in both the rest and stress test sets ( P < 0.05). In the visual assessment of patients with diaphragmatic attenuation, scores of 4 (similar to CT AC images) or 5 (indistinguishable from CT AC images) were assigned to most GEN AC images (65/68).

CONCLUSIONS

Our clinically feasible DL-based attenuation correction models can replace the CT-based method in Tl-201 MPS, and it would be useful in case SPECT/CT is unavailable for MPS.

Higher HbA1c Is Associated With Greater 2-Year Progression of White Matter Hyperintensities

White matter hyperintensity (WMH) lesions on brain MRI images are surrogate markers of cerebral small vessel disease. Longitudinal studies examining the association between diabetes and WMH progression have yielded mixed results. Thus, in this study, we investigated the association between HbA1c, a biomarker for the presence and severity of hyperglycemia, and longitudinal WMH change after adjusting for known risk factors for WMH progression. We recruited 64 participants from South Korean memory clinics to undergo brain MRI at the baseline and a 2-year follow-up. We found the following. First, higher HbA1c was associated with greater global WMH volume (WMHV) changes after adjusting for known risk factors (β = 7.7 × 10-4; P = 0.025). Second, the association between baseline WMHV and WMHV progression was only significant at diabetic levels of HbA1c (P < 0.05, when HbA1c >6.51%), and non-apolipoprotein E (APOE) ε4 carriers had a stronger association between HbA1c and WMHV progression (β = -2.59 × 10-3; P = 0.004). Third, associations of WMHV progression with HbA1c were particularly apparent for deep WMHV change (β = 7.17 × 10-4; P < 0.01) compared with periventricular WMHV change and, for frontal (β = 5.00 × 10-4; P < 0.001) and parietal (β = 1.53 × 10-4; P < 0.05) lobes, WMHV change compared with occipital and temporal WMHV change. In conclusion, higher HbA1c levels were associated with greater 2-year WMHV progression, especially in non-APOE ε4 participants or those with diabetic levels of HbA1c. These findings demonstrate that diabetes may potentially exacerbate cerebrovascular and white matter disease.

ARTICLE HIGHLIGHTS

Is the 'safe zone' identified in preoperative computed tomography helpful for choosing optimal implant for fixation of radial head fracture?

The purpose of this study is to assess the clinical significance of the radiologic safe zone based on computed tomography and to compare the outcomes of three different implants for fixation of isolated radial head fractures. We retrospectively reviewed 367 patients who underwent internal fixation for isolated radial head fractures. We newly defined two subtypes of Mason type II fractures associated with the radiographic safe zone (IIA, two-part fracture allowing for safe fixation of plate; IIB, two-part fracture not allowing for safe fixation). 170 patients (CCS group, n = 82; HCS group, n = 31; plate group, n = 57) were investigated with no significant differences in demographics. The range of pronation and supination at 1 month postoperatively (P = 0.04 and P = 0.04) and the range of supination at 6 and 12 months postoperatively (P = 0.03 and P = 0.03) were significantly smaller in the plate group. In Mason type IIB fractures, the average MEPS was higher in the CCS and HSC groups than in the plate group (P = 0.01 and P = 0.02). And the average DASH score was lower in the CCS and HCS groups (P < 0.01 and P < 0.01). Evaluation of the radiologic safe zone is potentially helpful in selecting better surgical fixation option. For type III fractures, 2.3-mm cortical screws would be a better option than Acutrak screws. Plates would not be suitable for type IIB radial head fractures.

Neurofilament light chain and cardiac MIBG uptake as predictors for phenoconversion in isolated REM sleep behavior disorder

BACKGROUND

Isolated rapid-eye-movement (REM) sleep behavior disorder (iRBD) is considered as a prodromal stage of either multiple system atrophy (MSA) or Lewy body disease (LBD; Parkinson's disease and dementia with Lewy bodies). However, current knowledge is limited in predicting and differentiating the type of future phenoconversion in iRBD patients. We investigated the role of plasma neurofilament light chain (NfL) and cardiac metaiodobenzylguanidine (MIBG) uptake as predictors for phenoconversion.

METHODS

Forty patients with iRBD were enrolled between April 2018 and October 2019 and prospectively followed every 3 months to determine phenoconversion to either MSA or LBD. Plasma NfL levels were measured at enrollment. Cardiac MIBG uptake and striatal dopamine transporter uptake were assessed at baseline.

RESULTS

Patients were followed for a median of 2.92 years. Four patients converted to MSA and 7 to LBD. Plasma NfL level at baseline was significantly higher in future MSA-converters (median 23.2 pg/mL) when compared with the rest of the samples (median 14.1 pg/mL, p = 0.003). NfL level above 21.3 pg/mL predicted phenoconversion to MSA with the sensitivity of 100% and specificity of 94.3%. Baseline MIBG heart-to-mediastinum ratio of LBD-converters (median 1.10) was significantly lower when compared with the rest (median 2.00, p < 0.001). Heart-to-mediastinum ratio below 1.545 predicted phenoconversion to LBD with the sensitivity of 100% and specificity of 92.9%.

CONCLUSIONS

Plasma NfL and cardiac MIBG uptake may be useful biomarkers in predicting phenoconversion of iRBD. Elevated plasma NfL levels may suggest imminent phenoconversion to MSA, whereas low cardiac MIBG uptake suggests phenoconversion to LBD.

Establishment and characterization of an immortalized bovine intestinal epithelial cell line

Primary bovine intestinal epithelial cells (PBIECs) are an important model for studying the molecular and pathogenic mechanisms of diseases affecting the bovine intestine. It is difficult to obtain and grow PBIECs stably, and their short lifespan greatly limits their application. Therefore, the purpose of this study was to create a cell line for exploring the mechanisms of pathogen infection in bovine intestinal epithelial cells in vitro. We isolated and cultured PBIECs and established an immortalized BIEC line by transfecting PBIECs with the pCI-neo-hTERT (human telomerase reverse transcriptase) recombinant plasmid. The immortalized cell line (BIECs-21) retained structure and function similar to that of the PBIECs. The marker proteins characteristic of epithelial cells, cytokeratin 18 (CK18), occludin, zonula occludens protein 1 (ZO-1), E-cadherin and enterokinase, were all positive in the immortalized cell line, and the cell structure, growth rate, karyotype, serum dependence and contact inhibition were normal. The hTERT gene was successfully transferred into BIECs-21 where it remained stable and was highly expressed. The transport of short-chain fatty acids and glucose uptake by the BIECs-21 was consistent with PBIECs, and we showed that they could be infected with the intestinal parasite, Neospora caninum. The immortalized BIECs-21, which have exceeded 80 passages, were structurally and functionally similar to the primary BIECs and thus provide a valuable research tool for investigating the mechanism of pathogen infection of the bovine intestinal epithelium in vitro.

Comparison of automated quantification of amyloid deposition between PMOD and Heuron

Several programs are widely used for clinical and research purposes to automatically quantify the degree of amyloid deposition in the brain using positron emission tomography (PET) images. Given that very few studies have investigated the use of Heuron, a PET image quantification software approved for clinical use, this study aimed to compare amyloid deposition values quantified from ¹⁸F-flutemetamol PET images using PMOD and Heuron. Amyloid PET data obtained from 408 patients were analysed using each quantitative program; moreover, the standardized uptake value ratios (SUVRs) of target areas were obtained by dividing the standardized uptake value (SUV) of the target region by the SUV of cerebellar grey matter as a reference. Compared with PMOD, Heuron yielded significantly higher SUVRs for all target areas (paired sample t-test, p < 0.001), except for the PC/PCC (p = 0.986). However, the Bland-Altman plot analysis indicated that the two quantitative methods may be used interchangeably. Moreover, receiver operating characteristic curve analysis revealed no significant between-method difference in the performance of the SUVRs in evaluating the visual positivity of amyloid deposits (p = 0.948). In conclusion, Heuron and PMOD have comparable performance in quantifying the degree of amyloid deposits in PET images.

Dual-phase 18 F-FP-CIT positron emission tomography and cardiac 123 I-MIBG scintigraphy of Parkinson's disease patients with GBA mutations: evidence of the body-first type?

BACKGROUND AND PURPOSE

Parkinson's disease (PD) with glucocerebrosidase (GBA) gene mutation (GBA-PD) is known to show more rapid clinical progression than sporadic PD without GBA mutation (sPD). This study was performed to delineate the specific patterns of cortical hypoperfusion, dopamine transporter uptake and cardiac meta-iodobenzylguanidine (MIBG) uptake of GBA-PD in comparison to sPD.

METHODS

Through next-generation sequencing analysis targeting 41 genes, a total of 16 GBA-PD and 24 sPD patients (sex, age matched) were enrolled in the study, and the clinical, dual-phase [¹⁸ F]-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (^{1 8} F-FP-CIT) positron emission tomography (PET) and cardiac ¹²³ I-MIBG scintigraphy results were compared between the two groups.

RESULTS

The GBA-PD group had higher rates of rapid eye movement sleep behavior disorder, orthostatic hypotension and neuropsychiatric symptoms than the sPD group. Early-phase ¹⁸ F-FP-CIT PET showed significantly lower standard uptake value ratio on bilateral posterior parietal cortex (0.94 ± 0.05 vs. 1.02 ± 0.04, p = 0.011) and part of the occipital cortex (p < 0.05) in the GBA-PD group than the sPD group. In striatal dopamine transporter uptake, the regional standard uptake value ratio, asymmetry index and caudate-to-putamen ratio were similar between the two groups. The GBA-PD group had a lower heart-to-mediastinum uptake ratio in ¹²³ I-MIBG scintigraphy than the sPD group.

CONCLUSIONS

The GBA-PD patients showed decreased regional perfusion in the bilateral posterior parietal and occipital cortex. Cardiac sympathetic denervation and non-motor symptoms (orthostatic hypotension, rapid eye movement sleep behavior disorder) were more common in GBA-PD than sPD. These findings suggest that GBA-PD patients have more widespread peripheral (extranigral) α-synuclein accumulation, representing a body-first PD subtype.

Effect of withdrawal of thyroid hormones versus administration of recombinant human thyroid-stimulating hormone on renal function in thyroid cancer patients

This study was conducted to investigate the effects of thyroid hormone withdrawal (THW) and recombinant human thyroid-stimulating hormone (rhTSH) administration on renal function in patients with thyroid cancer after total thyroidectomy. This study included 202 patients who discontinued thyroid hormone therapy and/or received rhTSH after total thyroidectomy. Creatinine (Cr), blood urea nitrogen (BUN) levels, and estimated glomerular filtration rate (eGFR) were assessed at the following three time points: before thyroidectomy, at least 3 weeks after THW, and 1 day after the second injection of rhTSH. The median serum Cr level was significantly higher following THW compared to that before thyroidectomy (0.95 versus 0.70). In contrast, the median BUN level was significantly lower after THW compared to that before thyroidectomy (9.8 versus 11.3). Over a fifth (22.2%) of patients had abnormal eGFR values after THW, which was significantly greater than that before thyroidectomy. In contrast, renal parameter values after rhTSH administration were not significantly different than those before thyroidectomy. In conclusion, THW affects renal function in patients with thyroid cancer who have undergone total thyroidectomy. However, renal function in such patients is not affected by rhTSH administration.

Sublingual Gland Observed on Salivary Gland Scan

ABSTRACT

The major salivary glands, namely, the parotid, submandibular, and sublingual glands, are important in maintaining oral cavity health. A salivary gland scan is used to evaluate the uptake and excretory function of the salivary glands. By intravenously injecting 99m TcO 4- , which is distributed like chloride ions in the body, the glands become visible on the salivary gland scan. The parotid and submandibular glands are typically appreciated on the salivary gland scan, but the sublingual gland is not. We present a rare image of a prominent sublingual gland on a salivary gland scan.

Correlations between salivary gland scintigraphy and histopathologic data of salivary glands in patients with primary Sjogren's syndrome

OBJECTIVES

Our aim was to evaluate the association between salivary gland scintigraphy and the clinical parameters, including histological characteristics of salivary glands, in patients with primary Sjogren's syndrome (pSS).

METHODS

Forty-one pSS patients were included in the study. The patients who had received salivary gland scintigraphy and minor salivary gland biopsy were retrospectively analyzed. Salivary gland scintigraphy was interpreted via semi-quantitative methods obtained by calculating the peak uptake and washout of each gland using regions of interest. All specimens were examined by pathologists for focus scores and leukocyte common antigen (LCA) to determine the degree of inflammatory infiltration.

RESULTS

The mean age of pSS patients was 46.4 years, 82.9% were female, and the mean duration of symptoms was 2.5 years. The focus score was negatively correlated to the mean peak uptake (r = ‒0.396; p = 0.019), mean uptake (r = ‒0.388; p = 0.021), and mean percentage washout (r = ‒0.391; p = 0.02). In addition, the focus score and number of LCA positive cells per mm² were correlated with the clinical parameters including erythrocyte sedimentation rate, globulin, rheumatoid factor, unstimulated whole saliva, and stimulated whole saliva flow. The number of LCA positive cells per mm² was negatively correlated to leukocytes and hemoglobin.

CONCLUSION

Although the diagnostic role of salivary gland biopsy is widely accepted and features in the classification criteria of Sjogren's syndrome, salivary gland scintigraphy may be an acceptable alternative method especially if a non-invasive test is required.

Baseline Clinical and Biomarker Characteristics of Biobank Innovations for Chronic Cerebrovascular Disease With Alzheimer's Disease Study: BICWALZS

OBJECTIVE

We aimed to present the study design and baseline cross-sectional participant characteristics of biobank innovations for chronic cerebrovascular disease with Alzheimer's disease study (BICWALZS) participants.

METHODS

A total of 1,013 participants were enrolled in BICWALZS from October 2016 to December 2020. All participants underwent clinical assessments, basic blood tests, and standardized neuropsychological tests (n=1,013). We performed brain magnetic resonance imaging (MRI, n=817), brain amyloid positron emission tomography (PET, n=713), single nucleotide polymorphism microarray chip (K-Chip, n=949), locomotor activity assessment (actigraphy, n=200), and patient-derived dermal fibroblast sampling (n=175) on a subset of participants.

RESULTS

The mean age was 72.8 years, and 658 (65.0%) were females. Based on clinical assessments, total of 168, 534, 211, 80, and 20 had subjective cognitive decline, mild cognitive impairment (MCI), Alzheimer's dementia, vascular dementia, and other types of dementia or not otherwise specified, respectively. Based on neuroimaging biomarkers and cognition, 199, 159, 78, and 204 were cognitively normal (CN), Alzheimer's disease (AD)-related cognitive impairment, vascular cognitive impairment, and not otherwise specified due to mixed pathology (NOS). Each group exhibited many differences in various clinical, neuropsychological, and neuroimaging results at baseline. Baseline characteristics of BICWALZS participants in the MCI, AD, and vascular dementia groups were generally acceptable and consistent with 26 worldwide dementia cohorts and another independent AD cohort in Korea.

CONCLUSION

The BICWALZS is a prospective and longitudinal study assessing various clinical and biomarker characteristics in older adults with cognitive complaints. Details of the recruitment process, methodology, and baseline assessment results are described in this paper.

Simulating dose reduction for myocardial perfusion SPECT using a Poisson resampling method

Purpose

The purpose of this study was to determine the lowest Tl-201 dose that does not reduce the image quality of myocardial perfusion SPECT (MPS) by Poisson resampling simulation.

Methods

One hundred and twelve consecutive MPS data from patients with suspected or known coronary artery disease were collected retrospectively. Stress and rest MPS data were resampled using the Poisson method with 33%, 50%, 67%, and 100% count settings. Two nuclear medicine physicians assessed the image quality of reconstructed data visually by giving grades from - 2 to + 2. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were obtained on the workstation. Image quality grades and semi-quantitative scores were then compared among these resampled images.

Results

The proportions of "adequate" image quality were 0.48, 0.75, 0.92, and 0.96 for the groups of images with 33%, 50%, 67%, and 100% data, respectively. The quality of the resampled images was significantly degraded at 50% and 33% count settings, while the image quality was not different between 67 and 100% count settings. We also found that high body mass index further decreased image quality at 33% count setting. Among the semi-quantitative parameters, SSS and SRS showed a tendency to increase with a decline in count.

Conclusion

Based on the simulation results, Tl-201 dose for MPS can be reduced to 74 MBq without significant loss of image quality. However, the SSS and SRS can be changed significantly, and it needs to be further verified under the different conditions.

Plasma neurofilament light chain level and orthostatic hypotension in early Parkinson's disease

To delineate the impact of non-motor markers (REM sleep behavior disorder (RBD), orthostatic hypotension (OH), cardiac sympathetic denervation, hyposmia) on neuronal injury in early-stage Parkinson's disease (PD), we measured the plasma neurofilament light chain (NFL) level of PD patients and evaluated its relationship with these markers. The study population comprised a cohort of 77 patients with PD and 54 controls. OH was assessed using 5-min head-up tilt-table test. Other clinical parameters such as RBD, Unified Parkinson's Disease Rating Scale (UPDRS), cognition, Cross-Cultural Smell Identification Test (CCSIT), white matter hyperintensity (WMH), cardiac metaiodobenzylguanidine (MIBG) and striatal dopamine transporter (DAT) uptake were assessed. Plasma NFL levels were measured using Simoa platform. During mean 24.8 months of follow-up, 70 patients remained PD, 5 patients converted to Parkinson-plus syndrome (P + converter), and 2 were lost to follow-up. NFL level did not differ between PD and control groups (age-adjusted means 10.40 pg/mL vs 9.51 pg/mL, p = 0.151), but PD patients with OH (median 15.31 pg/mL) had higher levels compared with those without OH (median 9.2 pg/mL, p = 0.008), as well as the control group (median 9.7 pg/mL, p = 0.002). P + converter group had the highest plasma NFL level (38.17 pg/mL, p < 0.001). In a multiple regression analysis, OH, age, and disease duration independently correlated with plasma NFL level. This finding adds biomarker-based evidence for poor clinical outcomes associated with OH in patients with PD.

Correlation Between 18F-FDG Uptake and Immune Cell Infiltration in Metastatic Brain Lesions

Background

The purpose of this study was to investigate the correlation between ¹⁸F-fluorodeoxyglucose (FDG) uptake and infiltrating immune cells in metastatic brain lesions.

Methods

This retrospective study included 34 patients with metastatic brain lesions who underwent brain ¹⁸F-FDG positron emission tomography (PET)/computed tomography (CT) followed by surgery. ¹⁸F-FDG uptake ratio was calculated by dividing the standardized uptake value (SUV) of the metastatic brain lesion by the contralateral normal white matter uptake value. We investigated the clinicopathological characteristics of the patients and analyzed the correlation between ¹⁸F-FDG uptake and infiltration of various immune cells. In addition, we evaluated immune-expression levels of glucose transporter 1 (GLUT1), hexokinase 2 (HK2), and Ki-67 in metastatic brain lesions.

Results

The degree of ¹⁸F-FDG uptake of metastatic brain lesions was not significantly correlated with clinical parameters. There was no significant relationship between the ¹⁸F-FDG uptake and degree of immune cell infiltration in brain metastasis. Furthermore, other markers, such as GLUT1, HK2, and Ki-67, were not correlated with degree of ¹⁸F-FDG uptake. In metastatic brain lesions that originated from breast cancer, a higher degree of ¹⁸F-FDG uptake was observed in those with high expression of CD68.

Conclusions

In metastatic brain lesions, the degree of ¹⁸F-FDG uptake was not significantly associated with infiltration of immune cells. The ¹⁸F-FDG uptake of metastatic brain lesions from breast cancer, however, might be associated with macrophage activity.

Comparison of bone single-photon emission computed tomography (SPECT)/CT and bone scintigraphy in assessing knee joints

BACKGROUND

This study attempted to compare the radiopharmaceutical uptake findings of planar bone scintigraphy (BS) and single photon emission computed tomography (SPECT)/computed tomography (CT) performed on knee joints.

METHODS

We retrospectively included 104 patients who underwent bone SPECT/CT and BS 4 h after the intravenous administration of technetium-99m-hydroxymethylene diphosphonate (^99mTc-HDP) for pain in the knee joint. The uptake degree of each of the knee regions (medial femoral, lateral femoral, medial tibial, lateral tibial, and patellar area) in planar images and SPECT/CT were evaluated by visual (grades 0 to 2) and quantitative analyses (uptake counts for planar image and standardized uptake values [SUVs] for SPECT/CT).

RESULTS

The uptake grades assessed visually on the planar images differed significantly from the uptake grades on SPECT/CT images in all areas of the knee (all p < 0.001), and SPECT/CT imaging revealed a larger number of uptake lesions than those noted in planar imaging for each patient (3.3 ± 2.0 vs 2.4 ± 2.3, p < 0.0001). In all regions of the knee, all of the quantitative values, including uptake counts obtained from the planar image as well as the maximum SUV (SUVmax) and mean SUV (SUVmean) obtained from SPECT/CT, showed statistically higher values as their visual grades increased (all p < 0.001). However, when analyzed for each area, only the SUVmax showed a significant difference by grade in all knee regions. Quantitative uptake values obtained from planar images were moderately correlated with SUVs of SPECT/CT images (r = 0.58 for SUVmean and r = 0.53 for SUVmax, all p < 0.001) in the total knee regions. Looking at each area, there was a significant but low correlation between the uptake counts of the planar images and the SUVs on SPECT/CT in the right lateral tibial region (r = 0.45 for SUVmean, r = 0.31 for SUVmax, all p < 0.001).

CONCLUSIONS

In assessing knee joints, the findings of planar images and SPECT/CT images differ both visually and quantitatively, and more lesions can be found in SPECT/CT than in the planar images. The SUVmax could be a reliable value to evaluate knee joint uptake activity.

Usefulness of Staging Chest CT in Breast Cancer: Evaluating Diagnostic Yield of Chest CT According to the Molecular Subtype and Clinical Stage

The aim of this study is to investigate the clinical utility of staging chest CT in breast cancer by evaluating diagnostic yield (DY) of chest CT in detection of metastasis, according to the molecular subtype and clinical stage. This retrospective study included 840 patients with 855 breast cancers from January 2017 to December 2018. The number of patients in clinical stage 0/I, II, III and IV were 457 (53.5%), 298 (34.9%), 92 (10.8%) and 8 (0.9%), respectively. Molecular subtype was identified in 841 cancers and there were 709 (84.3%) luminal type, 55 (6.5%) human epidermal growth factor receptor 2 (HER2)-enriched type and 77 (9.2%) triple-negative (TN) type. The DYs in clinical stage 0/I, cII, cIII and cIV were 0.2% (1/457), 1.7% (5/298), 4.3% (4/92) and 100.0% (8/8), respectively. The DYs in luminal type, HER2-enriched type and TN type were 1.7% (12/709), 3.6% (2/55) and 2.6% (2/77), respectively. Clinical stage was associated with the DY (p = 0.000). However, molecular subtype was not related to the DY (p = 0.343). Molecular subtype could not provide useful information to determine whether staging chest CT should be performed in early-stage breast cancer. However, chest CT should be considered in advanced breast cancer.

Hilar Choledochal Cyst Mimicking Biliary Atresia on Hepatobiliary Scintigraphy: a Case Report

Hepatobiliary scintigraphy has been widely used for the differential diagnosis of neonatal cholestasis. Relatively good hepatic uptake with no evidence of excretion into the bowel for up to 24 h is a representative finding of biliary atresia. Hepatobiliary scintigraphy has very high sensitivity and moderate specificity. Here, we report a false-positive case of hepatobiliary scintigraphy in a child with a choledochal cyst, which mimicked biliary atresia.

Therapeutic effect of mesenchymal stem cells in an animal model of Alzheimer's disease evaluated by β-amyloid positron emission tomography imaging

OBJECTIVE

We evaluated the effects of bone marrow-derived mesenchymal stem cells in a model of Alzheimer's disease using serial [¹⁸F]Florbetaben positron emission tomography.

METHODS

3xTg Alzheimer's disease mice were treated with intravenously injected bone marrow-derived mesenchymal stem cells, and animals without stem cell therapy were used as controls. Serial [¹⁸F]Florbetaben positron emission tomography was performed after therapy. The standardized uptake value ratio was measured as the cortex standardized uptake value divided by the cerebellum standardized uptake value. Memory function and histological changes were observed using the Barnes maze test and β-amyloid-reactive cells.

RESULTS

Standardized uptake value ratio decreased significantly from day 14 after stem cell administration in the bone marrow-derived mesenchymal stem cells-treated group (n = 28). In contrast, there was no change in the ratio in control mice (n = 25) at any time point. In addition, mice that received bone marrow-derived mesenchymal stem cell therapy also exhibited significantly better memory function and less β-amyloid-immunopositive plaques compared to controls.

CONCLUSION

The therapeutic effect of intravenously injected bone marrow-derived mesenchymal stem cells in a mouse model of Alzheimer's disease was confirmed by β-amyloid positron emission tomography imaging, memory functional studies and histopathological evaluation.

Current Perspectives on 89Zr-PET Imaging

⁸⁹Zr is an emerging radionuclide that plays an essential role in immuno-positron emission tomography (PET) imaging. The long half-life of ⁸⁹Zr (t_1/2 = 3.3 days) is favorable for evaluating the in vivo distribution of monoclonal antibodies. Thus, the use of ⁸⁹Zr is promising for monitoring antibody-based cancer therapies. Immuno-PET combines the sensitivity of PET with the specificity of antibodies. A number of studies have been conducted to investigate the feasibility of ⁸⁹Zr immuno-PET imaging for predicting the efficacy of radioimmunotherapy and antibody therapies, imaging target expression, detecting target-expressing tumors, and the monitoring of anti-cancer chemotherapies. In this review, we summarize the current status of PET imaging using ⁸⁹Zr in both preclinical and clinical studies by highlighting the use of immuno-PET for the targets of high clinical relevance. We also present ⁸⁹Zr-PET applications other than immuno-PET, such as nanoparticle imaging and cell tracking. Finally, we discuss the limitations and the ongoing research being performed to overcome the remaining hurdles.

Expression of Cellular Receptors in the Ischemic Hemisphere of Mice with Increased Glucose Uptake

Many previous studies have shown reduced glucose uptake in the ischemic brain. In contrast, in a permanent unilateral common carotid artery occlusion (UCCAO) mouse model, our pilot experiments using 18F-fluorodeoxyglucose positron emission tomography (FDG PET) revealed that a subset of mice exhibited conspicuously high uptake of glucose in the ipsilateral hemisphere at 1 week post-occlusion (asymmetric group), whereas other mice showed symmetric uptake in both hemispheres (symmetric group). Thus, we aimed to understand the discrepancy between the two groups. Cerebral blood flow and histological/metabolic changes were analyzed using laser Doppler flowmetry and immunohistochemistry/Western blotting, respectively. Contrary to the increased glucose uptake observed in the ischemic cerebral hemisphere on FDG PET (p<0.001), cerebral blood flow tended to be lower in the asymmetric group than in the symmetric group (right to left ratio [%], 36.4±21.8 vs. 58.0±24.8, p=0.059). Neuronal death was observed only in the ischemic hemisphere of the asymmetric group. In contrast, astrocytes were more activated in the asymmetric group than in the symmetric group (p<0.05). Glucose transporter-1, and monocarboxylate transporter-1 were also upregulated in the asymmetric group, compared with the symmetric group (p<0.05, respectively). These results suggest that the increased FDG uptake was associated with relatively severe ischemia, and glucose transporter-1 upregulation and astrocyte activation. Glucose metabolism may thus be a compensatory mechanism in the moderately severe ischemic brain.

Prognostic Value of Skeletal Muscle Depletion Measured on Computed Tomography for Overall Survival in Patients with Non-Metastatic Breast Cancer

Purpose

The purpose of this study was to evaluate the prognostic value of skeletal muscle depletion measured on computed tomography (CT) in patients with non-metastatic invasive breast cancer.

Methods

This retrospective study included 577 consecutive women (mean age ± standard deviation: 48.9 ± 10.2 years with breast cancer who underwent a preoperative positron-emission tomography (PET)/CT scan and curative surgery between January 2012 and August 2014. The total abdominal muscle area (TAMA), subcutaneous fat area (SFA), and visceral fat area (VFA) were measured on CT images at the L3 vertebral level. Univariate and multivariate Cox proportional-hazard regression analyses were performed to evaluate whether there was an association between sarcopenia and overall survival (OS) outcome.

Results

Of the 577 women, 49 (8.5%) died after a mean of 46 months. The best TAMA threshold for predicting OS was 83.7 cm². The multivariate Cox proportional-hazard analysis revealed that sarcopenia (TAMA ≤ 83.70 cm²) was a strong prognostic biomarker (hazard ratio [HR], 1.951; 95% confidence interval [CI], 1.061–3.586), along with large tumor size, axillary lymph node metastasis, high nuclear grade, estrogen receptor status, and adjuvant radiation therapy. In the subgroup analysis of patients aged ≥ 50 years, TAMA (≤ 77.14 cm²) was a significant independent factor (HR, 2.856; 95% CI, 1.218–6.695).

Conclusion

Skeletal muscle depletion measured on CT was associated with worse OS outcome in patients with non-metastatic breast cancer.

Can the basal serum thyroglobulin level be used to predict the recombinant human TSH-stimulated thyroglobulin level in differentiated patients with thyroid cancer?

This study investigated the correlation between basal thyroglobulin (Tg) and recombinant human thyroid-stimulating hormone (rhTSH)-stimulated Tg in differentiated patients with thyroid cancer, and sought to determine whether the basal Tg level predicts the rhTSH-stimulated Tg level.We retrospectively enrolled 177 patients with papillary thyroid cancer (mean age = 44 years; 50 males, 127 females) who received rhTSH before radioiodine therapy (RIT). Serum Tg levels were measured 7 days before the 1st rhTSH injection (basal Tg) and on the days of RIT (rhTSH-stimulated Tg). Patients were divided into 3 groups according to rhTSH-stimulated Tg cut-off levels of 2, 5, and 10 ng/mL. The correlation between basal Tg and rhTSH-stimulated Tg levels was assessed, and whether basal Tg was useful in predicting the rhTSH-stimulated Tg level was determined.A significant positive correlation was observed between basal and rhTSH-stimulated Tg levels (|rho| = 0.48, P < .0001). The basal Tg level had significant diagnostic ability in predicting an rhTSH-stimulated Tg level of 2 ng/mL or higher, and the optimal basal Tg level for this prediction was 0.3 ng/mL (AUC = 0.77, P < .0001). A basal Tg level of 0.5 ng/mL was optimal for predicting rhTSH-stimulated Tg levels of 5 ng/mL or higher (AUC = 0.81, P < .0001), and of 10 ng/mL or higher (AUC = 0.82, P = .0171).The basal Tg level was significantly correlated with the rhTSH-stimulated Tg level. If the basal Tg level is >0.3 or 0.5 ng/mL, then the rhTSH-stimulated Tg level can be expected to be sufficiently high to necessitate clinical examination.

Neural correlates and gait characteristics for hypoxic-ischemic brain injury induced freezing of gait

OBJECTIVE

To investigate gait characteristics in patients with freezing of gait (FOG) after hypoxic-ischemic brain injury (HIBI) and to elucidate neural correlates for FOG using F-18 fluoro-2-deoxy-d-glucose positron emission tomography.

METHODS

We enrolled 12 patients with FOG after HIBI and 17 patients without FOG after HIBI. We performed three-dimensional gait analyses and compared each parameter and gait variability. Brain metabolism was measured, and we compared regional brain metabolism using a voxel-by-voxel-based statistical mapping analysis.

RESULTS

The FOG group revealed a significantly decreased joint range of motion (ROM), particularly in the sagittal plane for three-joint summated ROM (p < 0.0025). Spatiotemporal results demonstrated that stride length and step length were decreased in the with FOG group (p < 0.005). FOG severity was negatively correlated with brain metabolism in the left thalamus, and three-joint summated ROM in the sagittal plane was positively associated with brain metabolism in the left thalamus and midbrain (p < 0.05).

CONCLUSIONS

Central organizational level amplitude disorder may play an important role in the pathophysiology, and disturbance in the cholinergic pathway might contribute to the development of FOG in patients with HIBI.

SIGNIFICANCE

These findings contribute to understanding FOG in HIBI.

Clinicopathologic parameters associated with the FDG-avidity in staging of early gastric cancer using 18F-FDG PET

This study investigated the clinicopathologic factors associated with 2-[F]fluoro-2-deoxy-D-glucose (F-FDG) uptake of early gastric cancer (EGC) and used them to design a clinical scoring method to predict FDG-avidity of EGC.Two hundred twenty-nine retrospectively enrolled patients underwent preoperative F-FDG positron emission tomography/computed tomography (PET/CT). Histologic information was obtained by gastrectomy (n = 195) or endoscopic mucosal dissection (n = 34). The association between clinicopathologic factors and F-FDG uptake by the primary tumor was determined. The results were used to develop a clinical scoring method.F-FDG uptake was detected in 49 (17.5%) patients. According to univariate analysis, location, gross type, World Health Organization classification, Lauren classification, size, depth of invasion, and lymphatic invasion were significant variables affecting F-FDG uptake (all P < .05). According to multivariate analysis, location (lower 3rd, P = .035), gross type (0-I, 0-IIa, P < .001), size (≥2.5 cm, P = .026), and depth of invasion (submucosa, P = .007) were significantly associated with FDG-avidity. A clinical scoring system, ranged from 0 to 4, was developed by giving one score to 4 independent variables. A cut-off value of 2.5 showed good prediction of FDG-avidity in EGCs, with a sensitivity and specificity of 65.0% and 85.2%, respectively.F-FDG uptake by EGC depends on location, gross type, size, and depth of invasion of the primary tumor. A clinical scoring system based on clinicopathologic variables can predict the FDG-avidity of primary tumors in patients with EGC.

The effect of sex hormones on normal breast tissue metabolism: Evaluation by FDG PET/CT

This study investigated the effect of sex hormones on F-fluorodeoxyglucose (FDG) uptake in normal breast tissue.The retrospective study included 249 premenopausal women (median age, 45 years) who were diagnosed with unilateral breast cancer and underwent FDG positron emission tomography/computed tomography and hormone tests. The volume of interest was within the contralateral normal breast and the standardized uptake values (SUVs) were measured. The correlations of sex hormones (including estrogen, progesterone, testosterone, follicle-stimulating hormone [FSH] and luteinizing hormone [LH]) with the SUVs of the normal breast were analyzed.There was a weak negative correlation between age and breast FDG uptake (P = .012, Spearman coefficient = -.16 for the maximum standardized uptake values [SUVmax]), especially in the luteal phase group (P = .005, Spearman coefficient = -.27 for SUVmax). The SUVs of normal breast tissue were increased when progesterone levels were higher (P = .043, Spearman coefficient = .13 for SUVmax). In the irregular menstrual cycle group, FDG uptake in the breast decreased as FSH (P = .027, Spearman coefficient = -.42 for SUVmax) and LH (P = .048, Spearman coefficient = -.44 for SUVmax) increased.Glucose metabolism of normal breast tissue decreases with age, and progesterone weakly affects breast FDG uptake. Gonadotropins may affect breast FDG uptake in premenopausal women with irregular menstrual cycles.

Clinical characteristics and role of whole-body bone scan in multifocal osteonecrosis

Background

Multifocal osteonecrosis (ON) is defined as ON involving three or more distinct anatomical sites. We investigated the clinical characteristics and utility of whole-body bone scans (WBBS) in patients with multifocal ON.

Methods

A total of 254 patients with ON confirmed by magnetic resonance imaging (MRI) or X-rays of the hips or other anatomic regions were evaluated using WBBS and divided into those with multifocal disease and those with oligofocal disease; their clinical characteristics were then compared. All data were analyzed retrospectively both visually and quantitatively (via uptake grading and defect scoring). Associations between the MRI Association Research Circulation Osseous (ARCO) classification and bone scan photon defects and uptake grade were assessed. Factors associated with multifocal ON were identified using logistic regression.

Results

Of the 254 ON patients, 26 (10.2%) had multifocal ON. Their mean age (42.8 ± 14.3 years) was less than that of patients with oligofocal ON (50.9 ± 15.4 years; p = 0.011). Comorbidities, corticosteroid use, and treatment with immunosuppressive agents were more frequent in patients with multifocal ON. Age (odds ratio [OR] = 0.964, p = 0.013), the presence of a comorbidity (OR = 3.387, p = 0.006), present corticosteroid use (OR = 5.696, p < 0.001), and treatment with immunosuppressive agents (OR = 3.447, p = 0.004) were significantly associated with multifocal ON. The MRI ARCO classification was not associated with photon defects in the bone scans of those with femoral ON. However, the ARCO classification was significantly associated with uptake grade.

Conclusions

WBBS may be an additional tool for evaluating ON patients with risk factors for multiple ON, such as younger age, corticosteroid use, and comorbidities.

Radiolabeled Anti-Adenosine Triphosphate Synthase Monoclonal Antibody as a Theragnostic Agent Targeting Angiogenesis

INTRODUCTION

The potential of a radioiodine-labeled, anti-adenosine triphosphate synthase monoclonal antibody (ATPS mAb) as a theragnostic agent for simultaneous cancer imaging and treatment was evaluated.

METHODS

Adenosine triphosphate synthase monoclonal antibody was labeled with radioiodine, then radiotracer uptake was measured in 6 different cancer cell lines. In vivo biodistribution was evaluated 24 and 48 hours after intravenous injection of ¹²⁵I-ATPS mAb into MKN-45 tumor-bearing mice (n = 3). For radioimmunotherapy, 18.5 MBq ¹³¹I-ATPS mAb (n = 7), isotype immunoglobulin G (IgG) (n = 6), and vehicle (n = 6) were injected into MKN-45 tumor-bearing mice for 4 weeks, and tumor volume and percentage of tumor growth inhibition (TGI) were compared each week.

RESULTS

MKN-45 cells showed the highest in vitro cellular binding after 4 hours (0.00324 ± 0.00013%/μg), which was significantly inhibited by unlabeled ATPS mAb at concentrations of greater than 0.4 μM. The in vitro retention rate of ¹²⁵I-ATPS mAb in MKN-45 cells was 64.1% ± 1.0% at 60 minutes. The highest tumor uptake of ¹²⁵I-ATPS mAb in MKN-45 tumor-bearing mice was achieved 24 hours after injection (6.26% ± 0.47% injected dose [ID]/g), whereas tumor to muscle and tumor to blood ratios peaked at 48 hours. The 24-hour tumor uptake decreased to 3.43% ± 0.85% ID/g by blocking with unlabeled ATPS mAb. After 4 weeks of treatment, mice receiving ¹³¹I-ATPS mAb had significantly smaller tumors (679.4 ± 232.3 mm³) compared with control (1687.6 ± 420.4 mm³, P = .0431) and IgG-treated mice (2870.2 ± 484.1 mm³, P = .0010). The percentage of TGI of ¹³¹I-ATPS mAb was greater than 50% during the entire study period (range: 53.7%-75.9%).

CONCLUSION

The specific binding and antitumor effects of radioiodinated ATPS mAb were confirmed in in vitro and in vivo models of stomach cancer.

In vivo tracking of intravenously injected mesenchymal stem cells in an Alzheimer's animal model

Purpose:

The purpose of this study was to investigate how intravenously injected bone marrow-derived mesenchymal stem cells (BMSCs) are distributed in the body of an Alzheimer’s disease (AD) animal model.

Methods:

Stem cells were collected from bone marrow of mice and labeled with Indium-111 (¹¹¹In). The ¹¹¹In-labeled BMSCs were infused intravenously into 3×Tg-AD mice in the AD group and non-transgenic mice (B6129SF2/J) as controls. Biodistribution was evaluated with a gamma counter and gamma camera 24 and 48 h after injecting the stem cells.

Results:

A gamma count of the brain showed a higher distribution of labeled cells in the AD model than in the control group at 24 (p = .0004) and 48 h (p = .0016) after injection of the BMSCs. Similar results were observed by gamma camera imaging (i.e., brain uptake in the AD model was significantly higher than that in the control group). Among the other organs, uptake by the spleen was the highest in both groups. More BMSCs were found in the lungs of the control group than in those of the AD group.

Conclusions:

These results suggest that more intravenously infused BMSCs reached the brain in the AD model than in the control group, but the numbers of stem cells reaching the brain was very small.

Metabolic Activity of Normal Glandular Tissue on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Correlation with Menstrual Cycles and Parenchymal Enhancements

Purpose

The aims of our study were to correlate the degree of metabolic activity in normal glandular tissue measured on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) with qualitative background parenchymal enhancement (BPE) grades on magnetic resonance imaging (MRI), and to investigate the change in standardized uptake value (SUV) according to the patients' menstrual cycles.

Methods

From January 2013 to December 2015, 298 consecutive premenopausal patients with breast cancer who underwent both breast MRI and ¹⁸F-FDG PET/CT were identified. BPE was evaluated in the contralateral breast of cancer patients and categorized as minimal, mild, moderate, or marked based on Breast Imaging Reporting and Data System criteria. We analyzed the correlation between BPE and maximum SUV (SUVmax) and mean SUV (SUVmean) values. We also analyzed the metabolic activity of normal glandular tissue according to the patients' menstrual cycles.

Results

The mean SUVmax and SUVmean values differed significantly according to BPE grade (p<0001), with the lowest values occurring in the minimal group and the highest values occurring in the marked group. Spearman's correlation coefficients revealed moderate correlations between BPE grade and SUVmax (r=0.472, p<0.001) and BPE and SUVmean (r=0.498, p<0.001). The mean SUVmax and SUVmean values differed significantly according to the patients' menstrual cycles, with the highest values in the 3rd week and the lowest value in the 2nd week. Of 29 patients with low metabolic parenchyma (high BPE but low SUVmean values), 17 (58.6%) were in the 4th week of their menstrual cycle.

Conclusion

The metabolic activity of normal breast parenchyma, which is highest in the 3rd week and lowest in the 2nd week of the menstrual cycle, correlates moderately with BPE on MRI. Metabolic activity tends to be lower than blood flow and vessel permeability in the 4th week of the menstrual cycle.

Prognostic utility of FDG PET/CT and bone scintigraphy in breast cancer patients with bone-only metastasis

We performed this retrospective clinical study to examine the prognostic power of bone scintigraphy (BS) and F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in terms of overall survival (OS) of breast cancer with bone-only metastasis.We retrospectively evaluated 100 female invasive ductal breast cancer patients (mean age 48.1 years) with bone-only metastasis. Twenty-five patients had human epidermal growth factor receptor 2 (HER2)-positive tumors, 65 were estrogen receptor (ER) and/or progesterone receptor (PR)-positive, HER2-negative tumors, and 10 were triple negative tumors. The patients were treated properly with various treatments, including chemotherapy, radiotherapy, hormone, and bisphosphonate therapy, based on their clinical status. All patients underwent BS and FDG PET/CT at baseline and 1 year after treatment. The baseline and follow images were visually compared, and the patients were grouped as responders or nonresponders based on their images. OS was compared between the groups.The mean OS after the diagnosis of bone-only metastasis was 57.6 months. Fifty-one patients (51%) died within 5 years after diagnosis of metastasis. No difference in survival was evident between responders and nonresponders based on BS imaging data (P = .090). The response status based on PET imaging data waste only significant independent prognostic factor on multivariate analysis (P = .001). Survival was lower in nonresponders than in responders based on PET imaging (32.7% vs 66.4%; P < .001).Our findings suggest that the response status according to FDG PET imaging can be used to predict OS in breast cancer patients with bone-only metastasis.

Volume-based metabolic parameter of breast cancer on preoperative 18F-FDG PET/CT could predict axillary lymph node metastasis

The purpose of our study was to evaluate the association between metabolic parameters on FDG PET/CT and axillary lymph node metastasis (ALNM) in patients with invasive breast cancer.From January 2012 to December 2012, we analyzed 173 patients with invasive ductal carcinoma (IDC) who underwent both initial breast magnetic resonance imaging (MRI) and F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) examinations. All metabolic parameters were measured from the tumor volume segmented by a gradient-based method. Once the primary target lesion was segmented, maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated automatically by the MIMvista software.Mean age of 173 patients was 49 years. Of 173 patients, 45 (26%) showed ALNM. On univariate analysis, larger tumor size (>2.2 cm; P = .002), presence of lymphovascular invasion (P < .001), higher SUVmax (>2.82; P = .038), higher SUVmean (>1.2; P = .027), higher MTV (>2.38; P < .001), and higher TLG (>3.98; P = .007) were associated with a higher probability of ALNM. On multivariate analysis, presence of lymphovascular invasion (adjusted odds ratio [OR], 11.053; 95% CI, 4.403-27.751; P < .001) and higher MTV (>2.38) (adjusted OR, 2.696; 95% CI, 1.079-6.739; P = .034) maintained independent significance in predicting ALNM. In subgroup analysis of T2/T3 breast cancer, lymphovascular invasion (adjusted OR, 20.976; 95% CI, 5.431-81.010; P < .001) and higher MTV (>2.38) (adjusted OR, 4.906; 95% CI, 1.616-14.896; P = .005) were independent predictors of ALNM. However in T1 breast cancer, lymphovascular invasion (adjusted OR, 16.096; 95% CI, 2.517-102.939; P = .003) and larger SUV mean (>1.2) (adjusted OR, 13.275; 95% CI, 1.233-142.908; P = .033) were independent predictors while MTV was not.MTV may be associated with ALNM in patients with invasive breast cancer, particularly T2 and T3 stages. In T1 breast cancer, SUVmean was associated with ALNM.

The role of 18F-fluorodeoxyglucose positron emission tomography in the assessment of disease activity of adult-onset Still's disease

BACKGROUND/AIMS

18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has been suggested as a reliable imaging technique for monitoring of disease activity in patients with adult-onset Still's disease (AOSD). Therefore, we investigated the clinical significance of 18F-FDG PET/CT in Korean AOSD patients.

METHODS

Thirteen AOSD patients were included in the study. The PET/CT images were evaluated with visual and semiquantitative method using standardized uptake values (SUVs).

RESULTS

The presence of increased 18F-FDG uptake was noted in 90% of clinically active AOSD patients. 18F-FDG uptake was located in the lymph node, spleen, and bone marrow. Visual grade and SUV intensity of lymph node was significantly correlated with the systemic score of AOSD. Visual grade of spleen was significantly correlated with the systemic score, erythrocyte sedimentation rate (ESR), and ferritin. Additionally, visual grade and SUV intensity of bone marrow was significantly correlated with the systemic score, ESR, leukocyte, and neutrophil.

CONCLUSIONS

Visual grade and SUV intensity of lymph node, spleen, and bone marrow on 18F-FDG PET/CT scan showed significant correlations with known disease activity markers. The data suggest that 18F-FDG PET/CT scan may be a useful imaging technique for evaluation of disease activity in AOSD patients.

Brain metabolism in patients with freezing of gait after hypoxic-ischemic brain injury: A pilot study

Movement disorders are 1 of the long-term neurological complications that can occur after hypoxic-ischemic brain injury (HIBI). However, freezing of gait (FOG) after HIBI is rare. The aim of this study was to examine the brain metabolism of patients with FOG after HIBI using F-18 fluoro-2-deoxy-D-glucose positron emission tomography (F-18 FDG PET).We consecutively enrolled 11 patients with FOG after HIBI. The patients' overall brain metabolism was measured by F-18 FDG PET, and we compared their regional brain metabolic activity with that from 15 healthy controls using a voxel-by-voxel-based statistical mapping analysis. Additionally, we correlated each patient's FOG severity with the brain metabolism using a covariance analysis.Patients with FOG had significantly decreased brain glucose metabolism in the midbrain, bilateral thalamus, bilateral cingulate gyri, right supramarginal gyrus, right angular gyrus, right paracentral lobule, and left precentral gyrus (PFDR-corrected < .01, k = 50). No significant increases in brain metabolism were noted in patients with FOG. The covariance analysis identified significant correlations between the FOG severity and the brain metabolism in the right lingual gyrus, left fusiform gyrus, and bilateral cerebellar crus I (Puncorrected < 0.001, k = 50).Our data suggest that brain regions in the gait-related neural network, including the cerebral cortex, subcortical structures, brainstem, and cerebellum, may significantly contribute to the development of FOG in HIBI. Moreover, the FOG severity may be associated with the visual cortex and cerebellar regions.

Enhancing the Therapeutic Efficacy of 2-Deoxyglucose in Breast Cancer Cells Using Cell-cycle Synchronization

AIM

We assessed the effect of cell-cycle synchronization using the T-type calcium channel inhibitor mibefradil on the anticancer effects of 2-deoxy-D-glucose (2-DG) and glucose metabolism in breast cancer cells.

MATERIALS AND METHODS

MDA-MB-231 cells were treated with mibefradil, followed by 2-DG with/without paclitaxel, then cells were assessed for viability. Glucose metabolism was evaluated by ³H-2-DG uptake, lactate concentration, and membrane glucose transporter 1 expression after mibefradil treatment.

RESULTS

Viability was significantly lower in cells receiving the combination therapy of mibefradil and 2-DG relative to 2-DG treatment alone; addition of paclitaxel to the combination therapy further reduced the viability of breast cancer cells. Withdrawal of mibefradil resulted in a significant increase in cellular ³H-2-DG uptake uptake, a slight accumulation of lactate, and increased membrane glucose transporter 1 expression.

CONCLUSION

Mibefradil-induced cell-cycle synchronization enhanced the anticancer activity of 2-DG in breast cancer cells due to an increase in cellular glucose metabolism.

Value of volume-based metabolic parameters for predicting survival in breast cancer patients treated with neoadjuvant chemotherapy

We evaluated the role of metabolic parameters in the prediction of disease recurrence in operable invasive ductal breast cancer patients treated with neoadjuvant chemotherapy (NAC).We retrospectively evaluated 139 female patients (mean age, 46.5 years; range: 27-72 years) with invasive ductal breast cancer, treated with NAC followed by surgery. All patients underwent F-fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging at baseline and after completion of NAC before surgery. The prognostic significance of clinicopathological and imaging parameters for disease-free survival (DFS) was evaluated.Recurrence of cancer was detected in 31 of 139 patients (22.3%; follow-up period: 6-82 months). Baseline maximum standardized uptake value, metabolic tumor volume (MTV), and reduction rate (RR) of MTV after NAC were significant independent prognostic factors for DFS in a multivariate analysis (all P < 0.05). The survival functions differed significantly between low and high histological grades (P < 0.001). DFS of the patients with high baseline MTV (≥5.23 cm) was significantly poorer than that of low MTV patients (P = 0.019). The survival function of the group with low RR of MTV after NAC (≤90.72%) was poorer than the higher RR of the MTV group (P = 0.008).Our findings suggest that breast cancer patients who have a high histological grade, large baseline MTV, or a small RR of MTV after NAC should receive great attention to check for possible recurrence.

Subchondral bone scan uptake correlates with articular cartilage degeneration in osteoarthritic knees

AIM

The aim of this study was to analyze subchondral bone scan uptake in osteoarthritic knees with reference to subchondral bone microstructure and articular cartilage histology.

METHODS

This cross-sectional, laboratory study evaluated 123 human distal femoral condyle specimens of 67 patients after joint replacement surgery. All patients were preoperatively examined with bone scan of the knee joint. Specimens were evaluated for cartilage histology and micro-computed tomography analysis of subchondral bone. Data between bone scan, histology and micro-computed tomography were statistically analyzed using either coefficient of correlation, Student's t-test or one-way analysis of variance with Tukey post hoc test.

RESULTS

Bone scan grading and histological articular cartilage degeneration scores showed significant correlation (r = 0.812, P < 0.001). Both bone scan positive and histologically confirmed osteoarthritis samples showed increase in subchondral trabecular bone volume and thickness, reflected in micro-computed tomography. Overall, positive predictive value (%) of bone scan for osteoarthritic cartilage lesions was 91.9%, and the sensitivity and specificity were 88.3% and 60%, respectively. Histology showed that bone scan has both a high positive predictive and a low negative predictive value for detection of osteoarthritic cartilage lesions.

CONCLUSION

Bone scan uptake correlated with articular cartilage degeneration in osteoarthritic knees. Bone scan may be a useful diagnostic tool that reflects pathologic changes of cartilage in osteoarthritis.

Clinical significance of post-treatment 18F-fluorodeoxyglucose uptake in cervical lymph nodes in patients with diffuse large B-cell lymphoma

OBJECTIVES

We assessed the clinical significance of FDG uptake in cervical lymph nodes after treatment of patients with DLBCL.

METHODS

In total, 87 patients with DLBCL were enrolled. All patients had newly appeared FDG uptake in cervical lymph nodes on PET/CT during follow-up after cessation of therapy. Cervical lymph nodes were finally diagnosed as benign or malignant according to histopathological findings or follow-up PET. Clinical characteristics and PET findings were compared between groups and factors associated with malignant lesions were evaluated.

RESULTS

Only 8 (9.2 %) patients with cervical lymph nodes with FDG uptake ultimately had malignancy. FDG uptake lymph nodes appeared significantly earlier in the malignant group than in patients with benign FDG uptake (p = 0.013). Primary nodal lymphoma was more frequent in patients with cancer spread than in those with benign FDG uptake in lymph nodes (p < 0.001).

CONCLUSION

Most cervical lymph nodes with FDG uptake (about 91 %) appearing after treatment of malignant DLBCL were ultimately benign. The elapsed time between the end of therapy and the appearance of cervical lymph nodes with FDG uptake and the primary sites of lymphomas are helpful clues in determining which cases are malignant.

KEY POINTS

• About 91 % appearing after treatment of DLBCL were benign. • Elapsed time between therapy and FDG uptake was associated with malignancy. • Primary sites of lymphoma are helpful clues to determine malignancy.

The Highest Metabolic Activity on FDG PET Is Associated With Overall Survival in Limited-Stage Small-Cell Lung Cancer

We evaluated the prognostic value of F-fluorodeoxyglucose positron emission tomography (FDG PET) parameters for limited-stage small-cell lung cancer (LS-SCLC).We retrospectively enrolled 59 LS-SCLC patients who underwent pretreatment FDG PET/CT. Various PET parameters were measured in all malignant lesions, and we recorded the highest maximum standardized uptake value (SUVmax), and sum of metabolic tumor volume (MTVsum) and total lesion glycolysis (TLGsum). The relationship between the highest SUVmax and volumetric PET parameters was evaluated. The prognostic significances of PET parameters and clinical variables were assessed using Cox's proportional hazard regression analysis. Overall survival (OS) and progression-free survival (PFS) were assessed by the Kaplan-Meier method.The SUVmax of the highest metabolic lesion had a significant positive correlation with MTVsum and TLGsum (P < 0.001). Upon multivariate analysis, the highest SUVmax was an independent predictor of OS (1 unit increase, hazard ratio [HR]: 1.133, P = 0.003) and MTVsum was a significant prognostic factor of PFS (10-cm increase, HR: 1.027, P = 0.034) after adjusting for age, sex, performance status, tumor stage, and treatment modality. The highest SUVmax was a prognostic factor for PFS with marginal significance (1 unit increase, HR: 1.078, P = 0.053). Patients with higher SUVmax (≥11) were also characterized by a significantly shorter median OS (P < 0.001) and PFS (P = 0.002) compared with patients with lower SUVmax.The highest SUVmax is an independent prognostic factor for survival in LS-SCLC patients. Therefore, the highest SUVmax might be a possible imaging biomarker for risk stratification in LS-SCLC. A further study in a large cohort is needed to validate the prognostic significance of the parameter.

Comparison of Diagnostic Performance Between Visual and Quantitative Assessment of Bone Scintigraphy Results in Patients With Painful Temporomandibular Disorder

This retrospective clinical study was performed to evaluate whether a visual or quantitative method is more valuable for assessing painful temporomandibular disorder (TMD) using bone scintigraphy results.In total, 230 patients (172 women and 58 men) with TMD were enrolled. All patients were questioned about their temporomandibular joint (TMJ) pain. Bone scintigraphic data were acquired in all patients, and images were analyzed by visual and quantitative methods using the TMJ-to-skull uptake ratio. The diagnostic performances of both bone scintigraphic assessment methods for painful TMD were compared.In total, 241 of 460 TMJs (52.4%) were finally diagnosed with painful TMD. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the visual analysis for diagnosing painful TMD were 62.8%, 59.6%, 58.6%, 63.8%, and 61.1%, respectively. The quantitative assessment showed the ability to diagnose painful TMD with a sensitivity of 58.8% and specificity of 69.3%. The diagnostic ability of the visual analysis for diagnosing painful TMD was not significantly different from that of the quantitative analysis.Visual bone scintigraphic analysis showed a diagnostic utility similar to that of quantitative assessment for the diagnosis of painful TMD.

Relation Between F-18 FDG Uptake of PET/CT and BRAFV600E Mutation in Papillary Thyroid Cancer

BRAFV600E mutation and F-18 fluorodeoxyglucose (FDG) uptake are potential prognostic factors of papillary thyroid cancer (PTC). This study was performed to investigate the relationship between the BRAFV600E mutation and F-18 FDG uptake in PTC.We retrospectively included 169 PTC patients who underwent F-18 FDG positron emission tomography/computed tomography (PET/CT) before thyroidectomy from May 2009 to August 2012. Subjects were classified into overt PTC (>1 cm, n = 76) and papillary thyroid microcarcinoma (PTMC, n = 93) groups. Univariate and multivariate analyses were performed to assess the relationship between maximum standardized uptake value (SUVmax) of the primary tumors and clinicopathologic variables.The BRAFV600E mutation was detected in 82.2% (139/169). In all subjects, the BRAFV600E mutation and tumor size were independently related to SUVmax by multivariate analysis (P = 0.048 and P < 0.001, respectively). SUVmax was significantly higher in tumors with the BRAFV600E mutation than in those with wild-type BRAF (9.4 ± 10.9 vs 5.0 ± 4.1, P < 0.001). Similarly, in overt PTC group, the BRAFV600E mutation and tumor size were independently correlated with SUVmax (P = 0.032 and P = 0.001, respectively). By contrast, in PTMC group, only tumor size was significantly associated with SUVmax (P = 0.010). The presence of the BRAFV600E mutation is independently associated with high F-18 FDG uptake on preoperative PET/CT in patients with overt PTC, but this relationship was not evident in PTMC. This study provides a better understanding of the relationship between F-18 FDG uptake and BRAFV600E mutation in patients with PTC.

Correlation Between F-18 Fluorodeoxyglucose Positron Emission Tomography Metabolic Parameters and Dynamic Contrast-Enhanced MRI-Derived Perfusion Data in Patients with Invasive Ductal Breast Carcinoma

PURPOSE

The aim of this study was to establish possible relationships among the metabolic and vascular characteristics of breast cancer using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging.

METHODS

Sixty-seven female patients with invasive ductal breast carcinoma (age 32-79 years) who underwent FDG PET/CT and DCE-MRI prior to cancer treatment were included in the study. The maximum standardized uptake value (SUVmax), metabolic tumor volume, total lesion glycolysis (TLG), and heterogeneity factor (HF) were derived from FDG PET/CT. The DCE-MRI parameters K trans, K ep, and V e were obtained for all tumors, and relationships between the metabolic and perfusion parameters were sought via Spearman's rank correlation analysis. The prognostic significance of clinicopathological and imaging parameters in terms of recurrence-free survival (RFS) was also evaluated.

RESULTS

No significant correlation between perfusion and metabolic parameters (p > 0.05) was found, except between SUVmax and V e (p = 0.001, rho = -0.391). Recurrence developed in 12 of the 67 patients (17.9 %, follow-up period 8-41 months). Age (p = 0.016) and HF (p = 0.027) were significant independent predictors of recurrence-free survival (RFS) upon multivariate analysis. The RFS of patients under 40 years of age was significantly poorer than that of older patients (p < 0.001). Survival of patients with more heterogeneous tumors (HF less than -0.12) was poorer than those with relatively homogenous tumors (p = 0.033).

CONCLUSIONS

Tumors with higher levels of glucose metabolism (SUVmax values) exhibited higher tumor cellularities (V e values). Also, of the various metabolic and perfusion parameters available, tumor heterogeneity measured via FDG PET/CT (HF) may be useful in predicting RFS in breast cancer patients.

Improved dopamine transporter binding activity after bone marrow mesenchymal stem cell transplantation in a rat model of Parkinson's disease: small animal positron emission tomography study with F-18 FP-CIT

OBJECTIVES

We evaluated the effects of bone marrow-derived mesenchymal stem cells (BMSCs) in a model of Parkinson's disease (PD) using serial F-18 fluoropropylcarbomethoxyiodophenylnortropane (FP-CIT) PET.

METHODS

Hemiparkinsonian rats were treated with intravenously injected BMSCs, and animals without stem cell therapy were used as the controls. Serial FP-CIT PET was performed after therapy. The ratio of FP-CIT uptake in the lesion side to uptake in the normal side was measured. The changes in FP-CIT uptake were also analyzed using SPM. Behavioural and histological changes were observed using the rotational test and tyrosine hydroxylase (TH)-reactive cells.

RESULTS

FP-CIT uptake ratio was significantly different in the BMSCs treated group (n = 28) at each time point. In contrast, there was no difference in the ratio in control rats (n = 25) at any time point. SPM analysis also revealed that dopamine transporter binding activity was enhanced in the right basal ganglia area in only the BMSC therapy group. In addition, rats that received BMSC therapy also exhibited significantly improved rotational behaviour and preservation of TH-positive neurons compared to controls.

CONCLUSIONS

The therapeutic effect of intravenously injected BMSCs in a rat model of PD was confirmed by dopamine transporter PET imaging, rotational functional studies, and histopathological evaluation.

KEY POINTS

• Mesenchymal stem cells were intravenously injected to treat the PD rats • Dopamine transporter binding activity was improved after stem cell therapy • Stem cell therapy induced functional recovery and preservation of dopaminergic neurons • The effect of stem cells was confirmed by FP-CIT PET.

Prognostic significance of the intratumoral heterogeneity of (18) F-FDG uptake in oral cavity cancer

BACKGROUNDS

We evaluated the prognostic value of the intratumoral heterogeneity of (18) F-FDG uptake in oral cavity cancer.

MATERIALS AND METHODS

We enrolled 45 patients who underwent pretreatment (18) F-FDG PET/CT. The intratumoral heterogeneity of (18) F-FDG uptake was represented as the heterogeneity factor (HF), defined as the derivative (dV/dT) of a volume-threshold function for a primary tumor. We measured the maximum standardized uptake value (SUVmax ) and volumetric PET parameters. The relationship between HF and clinical parameters, as well as other PET parameters, was evaluated.

RESULTS

The HF was significantly correlated with SUVmax (r = -0.353, P = 0.017), metabolic tumor volume (r = -0.708, P < 0.0001), and total lesion glycolysis (r = -0.709, P < 0.0001). A multivariate analysis revealed not only cervical lymph node metastasis (hazard ratio = 5.983; P = 0.022) but also HF (hazard ratio = 2.49 × 10(-4) ; P = 0.002) to be independent predictors of overall survival. Those patients with HF < -0.13 showed a worse prognosis than those with HF ≥ -0.13 (P = 0.005).

CONCLUSIONS

The intratumoral heterogeneity of (18) F-FDG uptake may be a significant prognostic factor for overall survival in addition to cervical lymph node metastasis in oral cavity cancer. J. Surg. Oncol. 2014 110:702-706. © 2014 Wiley Periodicals, Inc.

Card-placing test in amnestic mild cognitive impairment and its neural correlates

BACKGROUND

[corrected] We investigated anatomical correlates of the card-placing test (CPT) in patients with amnestic mild cognitive impairment (aMCI).

METHODS

Fifteen aMCI patients underwent part A and part B of the CPT and FDG-PET. The CPT scores and MMSE scores of 29 cognitively normal people were used for comparison. Statistical parametric mapping (SPM) correlation analysis was used to extract the regions whose changes in regional cerebral metabolism correlated significantly with part A and B of the CPT with adjustment of age, education and sex of patients.

RESULTS

The aMCI patients had significantly lower MMSE scores (26.0 ± 2.0 vs. 28.2 ± 1.4, p < 0.001), CPT A (25.5 ± 3.5 vs. 27.7 ± 2.7, p = 0.026) and CPT B scores (16.3 ± 4.4 vs. 19.7 ± 3.7, p = 0.011) compared to the normal population. The test scores of part B of the CPT correlated well with hypometabolism of the posterior cingulate gyrus and precuneus.

CONCLUSIONS

This study suggests that the CPT B may reflect the functional status of the posterior cingulate gyrus in patients with aMCI.

Utility of MRI and PET/CT after neoadjuvant chemotherapy in breast cancer patients: correlation with pathological response grading system based on tumor cellularity

BACKGROUND

MRI and PET/CT are useful for assessing breast cancer patients after neoadjuvant chemotherapy (NAC).

PURPOSE

To investigate the utility of MRI and PET/CT in the prediction of pathologic response to neoadjuvant chemotherapy using Miller-Payne grading system in patients with breast cancer.

MATERIAL AND METHODS

From January 2008 to December 2010, 59 consecutive patients with pathologically proven breast cancer, who underwent neoadjuvant chemotherapy followed by surgery were retrospectively enrolled. The maximal diameter decrease rate and volume reduction rate by three-dimensional (3D) MRI and standardized uptake value (SUV) reduction rate by PET/CT were calculated and correlated with the Miller-Payne grading system using the Spearman rank correlation test. Patients with Miller-Payne grades 1 or 2 were classified into the non-responder group and patients with grades 3, 4, and 5 were in the responder group. To differentiate between responders and non-responders, receiver-operating characteristic (ROC) analysis was performed.

RESULTS

The volume reduction rate was 64.87 ± 46.95, diameter decrease rate was 48.09 ± 35.02, and SUV decrease rate was 62.10 ± 32.17. Among three parameters, the volume reduction rate was most correlated with histopathologic grades of regression (ρ = 0.755, P < .0001) followed by diameter decrease rate (ρ = 0.660, P < 0.0001), and SUV decrease rate of primary breast mass (ρ = 0.561, P = 0.0002). The area under the ROC curve (Az) value was largest in the volume reduction rate (Az = 0.9), followed by SUV decrease rate (Az = 0.875), and diameter decrease rate (Az = 0.849). The best cut-offs for differentiating responders from non-responders in the ROC curve analysis were a 50% decrease in diameter, 68.9% decrease in volume, and 60.1% decrease in SUV after NAC.

CONCLUSION

Volumetric measurement using 3D MRI combined with conventional diameter measurement may be more accurate to evaluate pathologic response after NAC.

Carotid Artery FDG Uptake May Serve as a Biomarker for Cardiovascular Risk Stratification in Asymptomatic Adults

PURPOSE

We investigated the relation between carotid artery FDG uptake and cardiovascular risk based on the Framingham risk score (FRS) and evaluated the possible role of FDG uptake in terms of risk stratification of asymptomatic adults.

METHODS

We evaluated 290 adults who underwent FDG PET/CT as part of general health screens. We calculated target-to-background ratios, corrected for pre-scan blood glucose levels, and obtained "TBRglu" values for both common carotid arteries. The FRS and the presence/absence of metabolic syndrome were recorded for each subject. Relationships among TBRglu values, metabolic syndrome status, and clinical parameters were assessed.

RESULTS

Carotid artery FDG uptake was significantly associated with clinical risk factors. Stepwise multiple regression analysis revealed that triglyceride levels, diabetes, and metabolic syndrome were independent determinants of high TBRglu. Of subjects with metabolic syndrome, those exhibiting high carotid artery FDG uptake had significantly higher levels of high sensitivity C-reactive protein (hsCRP). In subjects who did not have metabolic syndrome, FRSs were significantly elevated in those exhibiting high carotid artery FDG uptake compared to those with low uptake (13.1 ± 7.0 vs. 8.2 ± 7.4), as was also true of subjects with the syndrome (21.8 ± 16.0 vs. 13.5 ± 11.9).

CONCLUSION

High carotid FDG uptake is significantly associated with clinical risk factors and a greater FRS. Of subjects with metabolic syndrome, those with high carotid uptake had significantly higher hsCRP concentrations and FRSs. Therefore, carotid artery FDG activity may serve as a possible biomarker allowing cardiovascular risk stratification of asymptomatic populations.