Evaluation of regional cerebral glucose metabolism in patients with malignant lymphoma of the body using statistical image analysis

Evaluation of brain metabolism using F18-FDG PET/CT imaging in patients diagnosed with lung cancer

OBJECTIVES

Brain imaging of regional metabolic changes in cancer patients can provide insights into cancer biology. We aimed to detect regional metabolic changes in the brains of untreated lung cancer patients without brain metastases using 2-deoxy-2-[18F]fluoroglucose PET/computed tomography.

METHODS

The study included 44 lung cancer patients and 17 non-cancer patients as controls. Standardized uptake value (SUV) mean values of 68 different brain regions were recorded, and their ratios to whole brain and brainstem SUVmean were calculated.

RESULTS

Comparisons between the groups showed significant reductions in the frontal lobe, inferior temporal gyrus, and right cingulate and paracingulate gyrus ratios in the patient group. Conversely, the right nucleus caudatus and right pallidum ratios were elevated. Correlation analysis with total lesion glycolysis (TLG) revealed positive correlations in the basal ganglia, right insula, amygdala, and right hippocampus ratios. Negative correlations were observed in the left frontal lobe and some temporal and parietal regions.

CONCLUSIONS

While most brain regions showed reduced metabolism, potentially due to tumor-brain glucose competition, others were preserved or positively correlated with TLG, suggesting a link to poor prognosis. The reduced metabolism in the frontal lobe might be associated with depression and cognitive decline in cancer patients.

Miliary tuberculosis diagnosed by diffuse hepatic uptake on PET/CT and transjugular liver biopsy

The patient was an 81-year-old man. In his 20s, he had been treated with pharmacotherapy for pulmonary tuberculosis for 1 year. He presented to the Department of Respiratory Medicine with a chief complaint of dyspnea. The possibility of respiratory disease appeared to be low, but hepatic impairment was detected. The patient was thus referred to our department. Though the cause of hepatic impairment was unknown, the soluble interleukin-2 receptor level was elevated, suggesting malignant lymphoma. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) revealed diffuse, homogenous, intense FDG uptake in the entire liver, and transjugular liver biopsy confirmed the diagnosis. Histopathological examination revealed an epithelioid granuloma, and auramine staining was positive for bacilli suggestive of tuberculosis. CT revealed diffuse micronodular shadows in the lung, yielding a diagnosis of miliary tuberculosis. Therefore, the patient was prescribed antituberculosis medication by the Department of Respiratory Medicine. His subsequent clinical course was good. The miliary (hepatic) tuberculosis was typical based on the diffuse, homogenous, intense FDG uptake throughout the liver observed on PET-CT.

The remodeling of metabolic brain pattern in patients with extracranial diffuse large B-cell lymphoma

BACKGROUND

Owing to the advances in diagnosis and therapy, survival or remission rates for lymphoma have improved prominently. Apart from the lymphoma- and chemotherapy-related somatic symptom burden, increasing attention has been drawn to the health-related quality of life. The application of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) has been routinely recommended for the staging and response assessment of FDG-avid lymphoma. However, up till now, only a few researches have investigated the brain metabolic impairments in patients with pre-treatment lymphoma. The determination of the lymphoma-related metabolic brain pattern would facilitate exploring the tailored therapeutic regimen to alleviate not only the physiological, but also the psychological symptoms. In this retrospective study, we aimed to establish the diffuse large B-cell lymphoma-related pattern (DLBCLRP) of metabolic brain network and investigate the correlations between DLBCLRP and several indexes of the staging and response assessment.

RESULTS

The established DLBCLRP was characterized by the increased metabolic activity in bilateral cerebellum, brainstem, thalamus, striatum, hippocampus, amygdala, parahippocampal gyrus and right middle temporal gyrus and by the decreased metabolic activity in bilateral occipital lobe, parietal lobe, anterior cingulate gyrus, midcingulate cortex and medial frontal gyrus. Significant difference in the baseline expression of DLBCLRP was found among complete metabolic response (CMR), partial metabolic response (PMR) and progressive metabolic disease (PMD) groups (P < 0.01). DLBCLRP expressions were also significantly or tended to be positively correlated with international prognostic index (IPI) (rs = 0.306, P < 0.05), lg(total metabolic tumor volume, TMTV) (r = 0.298, P < 0.05) and lg(total lesion glycolysis, TLG) (r = 0.233, P = 0.064). Though no significant correlation of DLBCLRP expression was found with Ann Arbor staging or tumor SUVmax (P > 0.05), the post-treatment declines of DLBCLRP expression were significantly positively correlated with Ann Arbor staging (rs = 0.284, P < 0.05) and IPI (rs = 0.297, P < 0.05).

CONCLUSIONS

The proposed DLBCLRP would lay the foundation for further investigating the cerebral dysfunction related to DLBCL itself and/or treatments. Besides, the expression of DLBCLRP was associated with the tumor burden of lymphoma, implying a potential biomarker for prognosis.

Evaluation of the Effects of R-CHOP Chemotherapy on Brain Glucose Metabolism in Patients with Diffuse Large B Cell Lymphoma: A Baseline, Interim, and End-of-Treatment PET/CT Study

BACKGROUND

To investigate the effect of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy on brain glucose metabolism in patients with diffuse large B cell lymphoma (DLBCL).

METHODS

Seventy-two patients with newly diagnosed DLBCL underwent FDG PET/CT brain and whole-body scans at baseline (PET0), in the interim of chemotherapy (PET2), and at the end (PET6) of chemotherapy. All three brain scans of each patient were analyzed using statistical parametric mapping software.

RESULTS

Compared with the PET0 scan, the PET2 and PET6 scans revealed a significantly higher glucose metabolism throughout the whole brain, with the PET6 scan revealing a higher metabolism than the PET2 scan. Patients with a complete response (CR) displayed decreased glucose metabolism in the lingual gyrus and increased glucose metabolism in the pons after chemotherapy compared with the findings in patients with partial responses or progressive disease.

CONCLUSIONS

Brain glucose metabolism was affected by R-CHOP treatment throughout the entire chemotherapy protocol.

Brain laterality evaluated by F-18 fluorodeoxyglucose positron emission computed tomography in autism spectrum disorders

Background and rationale

Autism spectrum disorder (ASD) is a neuropsychiatric disorder that has no curative treatment. Little is known about the brain laterality in patients with ASD. F-18 fluorodeoxyglucose positron emission computed tomography (F-18 FDG PET/CT) is a neuroimaging technique that is suitable for ASD owing to its ability to detect whole brain functional abnormalities in a short time and is feasible in ASD patients. The purpose of this study was to evaluate brain laterality using F-18 FDG PET/CT in patients with high-functioning ASD.

Materials and methods

This case-control study recruited eight ASD patients who met the DSM-5 criteria, the recorded data of eight controls matched for age, sex, and handedness were also enrolled. The resting state of brain glucose metabolism in the regions of interest (ROIs) was analyzed using the Q.Brain software. Brain glucose metabolism and laterality index in each ROI of ASD patients were compared with those of the controls. The pattern of brain metabolism was analyzed using visual analysis and is reported in the data description.

Results

The ASD group’s overall brain glucose metabolism was lower than that of the control group in both the left and right hemispheres, with mean differences of 1.54 and 1.21, respectively. We found statistically lower mean glucose metabolism for ASD patients than controls in the left prefrontal lateral (Z = 1.96, p = 0.049). The left laterality index was found in nine ROIs for ASD and 11 ROIs for the control. The left laterality index in the ASD group was significantly lower than that in the control group in the prefrontal lateral (Z = 2.52, p = 0.012), precuneus (Z = 2.10, p = 0.036), and parietal inferior (Z = 1.96, p = 0.049) regions.

Conclusion

Individuals with ASD have lower brain glucose metabolism than control. In addition, the number of ROIs for left laterality index in the ASD group was lower than control. Left laterality defects may be one of the causes of ASD. This knowledge can be useful in the treatment of ASD by increasing the left-brain metabolism. This trial was registered in the Thai Clinical Trials Registry (TCTR20210705005).

Neuropsychiatric Manifestations of Lymphoma-Associated Cerebral Glucose Hypometabolism Can Be Reversed by Intensive Glucose Supplementation

Cerebral glucose hypometabolism (CGHM) is characterized by diffuse or focal reduction in uptake of glucose by the brain as determined on a FDG PET-CT. We report a case of lymphoma-associated cerebral glucose hypometabolism (LA-CGHM) in a patient with hepatosplenic T-cell lymphoma (HSTCL) whose neuropsychiatric symptoms were resolved with glucose supplementation. PET-CT scan showed diffuse cerebral hypometabolism in addition to focal hypermetabolism in the liver related to lymphomatous involvement. He responded rapidly to infusion of 10% dextrose with complete resolution of neurological symptoms on two separate occasions and was later maintained on oral glucose without relapse. While his neuropsychiatric symptoms improved, his aggressive lymphoma and chemo-refractory disease ultimately led to his demise. We suggest that LA-CGHM can cause neuropsychiatric manifestations which can be reversed by intensive glucose supplementation.

Regional changes with global brain hypometabolism indicates a physiological triage phenomenon and can explain shared pathophysiological events in Alzheimer's & small vessel diseases and delirium

While reduced global brain metabolism is known in aging, Alzheimer's disease (AD), small vessel disease (SVD) and delirium, explanation of regional brain metabolic (rBM) changes is a challenge. We hypothesized that this may be explained by "triage phenomenon", to preserve metabolic supply to vital brain areas. We studied changes in rBM in 69 patients with at least 5% decline in global brain metabolism during active lymphoma. There was significant decline in the rBM of the inferior parietal, precuneus, superior parietal, lateral occipital, primary visual cortices (P<0.001) and in the right lateral prefrontal cortex (P=0.01). Some areas showed no change; multiple areas had significantly increased rBM (e.g. medial prefrontal, anterior cingulate, pons, cerebellum and mesial temporal cortices; P<0.001). We conclude the existence of a physiological triage phenomenon and argue a new hypothetical model to explain the shared events in the pathophysiology of aging, AD, SVD and delirium.

Regional Brain Glucose Metabolism and Its Prognostic Value in Pretreatment Extranodal Natural Killer/T-Cell Lymphoma Patients

Objective

To explore regional brain glucose metabolic abnormalities of pretreatment stage I/II extranodal natural killer/T-cell lymphoma (ENKTL) patients using positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (¹⁸F-FDG PET/CT) and assess its prognostic value.

Methods

Sixty pretreatment stage I/II ENKTL patients were enrolled in this retrospective study and divided into survival (n = 45) and death (n = 15) groups according to their status at the end of follow-up. A control group consisted of 60 healthy subjects. Regional cerebral glucose metabolism was evaluated on a voxel-by-voxel basis using statistical parametric mapping (SPM8) under a certain significance level (P < 0. 001) and voxel threshold (K = 100 voxels).

Results

Decreased metabolism was noted in patients, involving the bilateral prefrontal and orbitofrontal cortex, partial parietal and occipital cortex, cingulate gyrus and cerebellum; the sensorimotor cortex was largely spared. Increased metabolism was observed in the bilateral putamen, amygdala, and parahippocampal gyrus. Compared with the survival group, the death group had higher metabolism in the bilateral amygdala, putamen, left thalamus, uncus, and parahippocampal gyrus. Only B symptoms were associated with the increased metabolism of basal ganglia and thalamus (BGT). Patients with high metabolic tumor volume, total lesion glycolysis (TLG) and BGT metabolism had a poor prognosis. TLG and maximum standardized uptake value (SUVmax) LBGT/SUVmaxRight cerebellum were associated with Eastern Cooperative Oncology Group (ECOG) and prognostic index of natural killer lymphoma and Epstein-Barr virus-DNA (PINKE) scores. In multivariate analysis, only ECOG was an independent prognostic factor of both progression-free survival (PFS) and overall survival (OS). PINKE was an independent prognostic factor of OS.

Conclusion

Pretreatment stage I/II ENKTL patients exhibited abnormal regional cerebral glucose metabolism. Higher pretreatment glucose metabolism in BGT could predict a relatively poor prognosis but did not surpass the predictive values of ECOG and PINKE in stage I/II ENKTL patients.

FDG PET imaging in multiple myeloma: implications for response assessments in clinical trials

18F-fluorodeoxyglucose positron emission tomography integrated with computed tomography (18F-FDG PET/CT) is an effective modality to assess disease burden, detect extra-medullary disease and monitor minimal residual disease (MRD) for multiple myeloma (MM) patients. This modality of imaging is incorporated in the International Myeloma Working Group (IMWG) response criteria that are widely used in MM clinical trials. Interpretative pitfalls are commonly encountered in 18F-FDG PET/CT studies and proper interpretation requires knowledge of the normal physiologic distribution of the tracer affecting available 18F-FDG for tumor tissue uptake. We describe a series of MM patients who exhibited a deep response to treatment, based on clinical features, serum markers and bone marrow (BM) biopsy. However, these patients seemed to have new lesions on post-therapy 18F-FDG PET/CT images which could be interpreted as progressive disease according to the IMWG criteria. Sequestration phenomenon, which is the disappearance of 18F-FDG sequestration by myeloma-infiltrated marrow after successful anti-myeloma therapy, could lead to unmasking of new 18F-FDG-avid lesions on post-therapy PET/CT due to higher 18F-FDG bioavailability to residual tumor tissue. Clinical correlation, awareness of the 18F-FDG sequestration in myeloma infiltrated BM and its impact on other 18F-FDG avid areas in the body are necessary to avoid potential pitfalls in end-of-treatment imaging interpretation. While considering patients for clinical trials, clinicians should be mindful of this sequestration phenomenon in the interpretation of post-therapy PET/CT imaging in MM patients with initially heavily infiltrated marrow.

An Overview of Multimodal Neuroimaging Using Nanoprobes

Nanomaterials have gained tremendous significance as contrast agents for both anatomical and functional preclinical bio-imaging. Contrary to conventional medical practices, molecular imaging plays an important role in exploring the affected cells, thus providing precision medical solutions. It has been observed that incorporating nanoprobes improves the overall efficacy of the diagnosis and treatment processes. These nano-agents and tracers are therefore often incorporated into preclinical therapeutic and diagnostic applications. Multimodal imaging approaches are well equipped with nanoprobes to explore neurological disorders, as they can display more than one type of characteristic in molecular imaging. Multimodal imaging systems are explored by researchers as they can provide both anatomical and functional details of tumors and affected tissues. In this review, we present the state-of-the-art research concerning multimodal imaging systems and nanoprobes for neuroimaging applications.