Glucose Positron Emission Research Articles

Synchronous dual primary malignancy of urinary bladder and hypopharynx: An extremely rare phenomenon

The diagnosis of multiple primary malignancy (MPM) is not uncommon. Nevertheless synchronous MPM involving urinary bladder and hypopharynx is an extremely unusual event. No such cases have been reported so far in English literature to our review. We report the case of 62-year-old male patient who presented with haematuria and later dysphagia to solids. Whole body ‘8F-fluro deoxy glucose positron emission tomography- computed tomography (‘8F- FDG PET-CT) revealed two distinct lesions one in hypopharynx and another in urinary bladder. Biopsy from the urinary bladder mass and the hypopharyngeal lesion were suggestive of urothelial carcinoma and poorly differentiated squamous cell carcinoma respectively. The patient was treated with concurrent chemo-radiotherapy to hypopharynx. Following treatment he had improvement of dysphagia. Haematuria had also stopped. Because of severe comorbidities the planned radical cystectomy or radiotherapy were deferred. Currently the patient is in symptomatic remission six months following treatment.

What can imaging tell us about cognitive impairment and dementia?

Dementia is a contemporary global health issue with far reaching consequences, not only for affected individuals and their families, but for national and global socio-economic conditions. The hallmark feature of dementia is that of irreversible cognitive decline, usually affecting memory, and impaired activities of daily living. Advances in healthcare worldwide have facilitated longer life spans, increasing the risks of developing cognitive decline and dementia in late life. Dementia remains a clinical diagnosis. The role of structural and molecular neuroimaging in patients with dementia is primarily supportive role rather than diagnostic, American and European guidelines recommending imaging to exclude treatable causes of dementia, such as tumor, hydrocephalus or intracranial haemorrhage, but also to distinguish between different dementia subtypes, the commonest of which is Alzheimer's disease. However, this depends on the availability of these imaging techniques at individual centres. Advanced magnetic resonance imaging (MRI) techniques, such as functional connectivity MRI, diffusion tensor imaging and magnetic resonance spectroscopy, and molecular imaging techniques, such as 18F fluoro-deoxy glucose positron emission tomography (PET), amyloid PET, tau PET, are currently within the realm of dementia research but are available for clinical use. Increasingly the research focus is on earlier identification of at risk preclinical individuals, for example due to family history. Intervention at the preclinical stages before irreversible brain damage occurs is currently the best hope of reducing the impact of dementia.

Non-invasive Evaluation for Epilepsy Surgery.

Epilepsy surgery is aimed to remove the brain tissues that are indispensable for generating patient’s epileptic seizures. There are two purposes in the pre-operative evaluation: localization of the epileptogenic zone and localization of function. Surgery is planned to remove possible epileptogenic zone while preserving functional area. Since no single diagnostic modality is superior to others in identifying and localizing the epileptogenic zone, multiple non-invasive evaluations are performed to estimate the location of the epileptogenic zone after concordance between evaluations. Essential components of non-invasive pre-surgical evaluation of epilepsy include detailed clinical history, long-term video-electroencephalography monitoring, epilepsy-protocol magnetic resonance imaging (MRI), and neuropsychological testing. However, a significant portion of drug-resistant epilepsy is associated with no or subtle MRI lesions or with ambiguous electro-clinical signs. Additional evaluations including fluoro-deoxy glucose positron emission tomography (FDG-PET), magnetoencephalography and ictal single photon emission computed tomography can play critical roles in planning surgery. FDG-PET should be registered on three-dimensional MRI for better detection of focal cortical dysplasia. All diagnostic tools are complementary to each other in defining the epileptogenic zone, so that it is always important to reassess the data based on other results to pick up or confirm subtle abnormalities.

Brain metabolism changes with 18F-fluorodeoxy- glucose-positron emission tomography in a patient with Cotard’s syndrome

Brain metabolism changes with ¹⁸F-fluorodeoxy- glucose-positron emission tomography in a patient with Cotard’s syndrome

FDG-PET reveals improved cardiac regeneration and attenuated adverse remodelling following Sitagliptin + G-CSF therapy after acute myocardial infarction.

Dual therapy comprising G-CSF for mobilization of bone marrow-derived progenitor cells (BMPCs), with simultaneous pharmacological inhibition of dipeptidylpeptidase-IV for enhanced myocardial recruitment of circulating BMPC via the SDF-1α/CXCR4-axis, has been shown to improve survival after acute myocardial infarction (AMI). Using an innovative method to provide non-invasive serial in vivo measurements and information on metabolic processes, we aimed to substantiate the possible effects of this therapeutic concept on cardiac remodelling after AMI using 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET). AMI was induced in C57BL/6 mice by performing surgical ligation of the left anterior descending artery in these mice. Animals were then treated with granulocyte-colony stimulating factor + Sitagliptin (GS) or placebo for a duration of 5 days following AMI. From serial PET scans, we verified that the infarct size in GS-treated mice (n = 13) was significantly reduced at Day 30 after AMI when compared with the mice receiving placebo (n = 10). Analyses showed a normalized FDG uptake on Day 6 in GS-treated mice, indicating an attenuation of the cardiac inflammatory response to AMI in treated animals. Furthermore, flow cytometry showed a significant increase in the anti-inflammatory M2-macrophages subpopulation in GS-treated animals. In comparing GS treated with placebo animals, those receiving GS-therapy showed a reduction in myocardial hypertrophy and left ventricular dilatation, which indicates the beneficial effect of GS treatment on cardiac remodelling. Remarkably, flow cytometry and immunohistochemistry showed an increase of myocardial c-kit positive cells in treated mice (n = 12 in both groups). Using the innovative method of micro-PET for non-invasive serial in vivo measurements of metabolic myocardial processes in mice, we were able to provide mechanistic evidence that GS therapy improves cardiac regeneration and reduces adverse remodelling after AMI.

Desmoid-Type Fibromatosis of the Thorax: CT, MRI, and FDG PET Characteristics in a Large Series From a Tertiary Referral Center.

The purpose of this study was to describe the radiologic findings of computed tomography (CT), magnetic resonance (MR) imaging, and 18F-fluorodeoxy glucose positron emission tomography (FDG PET) in desmoid-type fibromatosis of the thorax.We retrospectively evaluated 47 consecutive patients with pathologically proven desmoid-type fibromatosis from January 2005 to March 2015. Patients underwent CT (n = 36) and/or MR (n = 32), and 13 patients also underwent FDG PET. Based on CT and MR, the sizes, locations, margins, contours, presence of surrounding fat, extra-compartment extension, bone involvement, and neurovascular involvement of the tumors were recorded. The attenuation, signal intensity, enhancement pattern, and presence of internal low signal band or signal void of the tumors were evaluated. Initial image findings were then compared between 2 groups of tumors: group 1 with recurrence or progression, and group 2 with no recurrence or stable without treatment.Median age at diagnosis of the tumors was 45 years, range 4 to 96, female-to-male ratio 1.8. Median tumor long diameter was 65 mm (range, 22–126 mm). The most common locations were chest wall (42.6%), followed by supraclavicular area, shoulder or axillary area, and mediastinum. The tumors had well-defined margins (83.0%), lobulated in contours (66.0%) surrounding fat (63.8%), extra-compartment extensions (42.6%), bone involvements (42.6%), and neurovascular involvements (27.7%). On CT, tumors had low attenuation (60.0%) with mild enhancement (median 24 HU, range 0–52). On MR, they showed iso-signal intensity (SI) (96.9%) on T1-weighted images (WI), and high SI (90.6%) on T2WI images, with strong (87.5%) and heterogeneous (96.9%) enhancement. Internal low signal bands (84.4%) and signal voids (68.8%) were noted. The median value of maxSUV was 3.1 (range, 2.0–7.3). In group 1 (n = 19, 40.4%), 13 patients suffered recurrence and 6 experienced progression. Group 2 (n = 28, 59.6%) consisted of 21 patients with no recurrence and 7 stable patients receiving no treatment. Partially ill-defined margins (OR, 0.167; 95% CI 0.029–0.943; P = 0.043) was the independent predictor for recurrence or progression of tumor.Knowledge of the radiological findings in desmoid-type fibromatosis on CT, MR, and FDG PET may help to improve diagnosis. Tumors with partially ill-defined margins have a tendency to recur or progress.

Evaluation of Therapeutic Effects of Radiotherapy during Treatment of Lung Adenocarcinoma in Mice with Positron Emission Tomography Imaging of <sup>18</sup>F-FLT and <sup>18</sup>F-FDG

Purpose: To assess the role of 3'-deoxy-3'-18F-fluoro-thymidine (18F-FLT) and 2'-deoxy-2'-18F-fluorodeoxy- glucose (18F-FDG) positron emission tomography (PET) imaging in the evaluation of the therapeutic effects of radiotherapy during treatment of lung adenocarcinoma.Methods: Eighteen mice with lung adenocarcinoma were randomly divided into 2 groups; each group was randomly paired and evenly divided into three smaller groups, namely, A, B and C. Group A served as the control group without any treatment; mice in group B were received radiotherapy in sites of tumor. A single dose of 2000 cGy, 6MV x-ray was used in this experiment; mice in group C also received radiotherapy at sites of tumors two days before the experiment using the same procedure and dose as group B. Micro PET imaging was taken after intravenous injection of 18F-FLT and 18F-FDG through the mice’s tail.Results: The intake ratio of 18F-FLT and 18F-FDG was much higher at the tumor sites. After radiotherapy, 18F-FLT uptake was significantly lower than that of the control group (p < 0.05), while there was no obvious change of 18F-FDG uptake. There was a significant decrease in T/NT value of FLT PET imaging group 24 and 48 h after radiotherapy; a significant difference could be seen, compared with that before radiotherapy (p < 0.05).Conclusion: Change in 18F-FLT uptake induced by radiotherapy is more sensitive than that of 18F-FDG. Intake of 18F-FLT is lowered more significantly after radiotherapy than that of 18F-FDG, and this can serve as evidence that 18F-FLT is an effective tracer to monitor the therapeutic effect of radiotherapy on malignant tumors.Keywords: 3'-deoxy-3'-18F-fluoro-thymidine, 2'-deoxy-2'-18F-fluoro-deoxy-glucose, Radiotherapy, Positron Emission Tomography Imaging, Cell Proliferation, Lung Adenocarcinoma

Impact of Pretransplantation 18F-fluorodeoxy Glucose–Positron Emission Tomography Status on Outcomes after Allogeneic Hematopoietic Cell Transplantation for Non-Hodgkin Lymphoma

Assessment with 18F-fluorodeoxy glucose (FDG)–positron emission tomography (PET) before hematopoietic cell transplantation (HCT) for lymphoma may be prognostic for outcomes. Patients with chemotherapy-sensitive non–Hodgkin lymphoma (NHL) undergoing allogeneic HCT reported to the Center of International Blood and Marrow Transplantation Registry between 2007 and 2012 were included. Pre-HCT PET status (positive versus negative) was determined by the reporting transplantation centers. We analyzed 336 patients; median age was 55 years and 60% were males. Follicular lymphoma (n = 104) was more common than large cell (n = 85), mantle cell (n = 69), and mature natural killer or T cell lymphoma (n = 78); two thirds of the cohort received reduced-intensity conditioning; one half had unrelated donor grafts. Patients underwent PET scanning a median of 1 month (range, .07 to 2.83 months) before HCT; 159 were PET positive and 177 were PET negative. At 3 years, relapse/progression, progression-free survival (PFS), and overall survival (OS) in PET-positive versus PET-negative groups were 40% versus 26%; P = .007; 43% versus 47%; P = .47; and 58% versus 60%; P = .73, respectively. On multivariate analysis, a positive pretransplantation PET was associated with an increased risk of relapse/progression (risk ratio [RR], 1.86; P = .001) but was not associated with increased mortality (RR, 1.29, 95% confidence interval [CI], .96 to 1.7; P = .08), therapy failure (RR, 1.32; 95% CI, .95 to 1.84; P = .10), or nonrelapse mortality (RR, .75; 95% CI, .48 to 1.18; P = .22). PET status conferred no influence on graft-versus-host disease. A positive PET scan before HCT is associated with increased relapse risk but should not be interpreted as a barrier to a successful allograft. PET status does not appear to predict survival after allogeneic HCT for NHL.

Distinguishing between limited systemic scleroderma-associated pseudo-obstruction and peritoneal dissemination.

A 78-year-old woman receiving treatment for limited systemic scleroderma (SSc) underwent high anterior resection and partial liver resections for rectosigmoid colon cancer with multiple liver metastases. A year after surgery, an abdominal computed tomography (CT) demonstrated suspicion for peritoneal dissemination with an increase in ascites, and 18F-fluorodeoxy glucose-positron emission tomography-CT was suggestive of carcinomatosis. We began to decompress the small intestine and administer octreotide. However, the intestinal obstruction did not improve. Although intestinal pseudo-obstruction caused by limited SSc was considered as a differential diagnosis, we performed an exploratory laparotomy because the possibility of peritoneal dissemination-associated obstruction could not be excluded. We observed a moderate amount of serous ascites and dilatation of the small intestine that was white in color, hard, and with limited contractility. There was no evidence of peritoneal dissemination nor of mechanical obstruction. Our experience thus shows the difficulty of distinguishing SSc-associated intestinal pseudo-obstruction from peritoneal dissemination.

18-F flourodeoxy glucose positron emission tomography-computed tomography imaging: A viable alternative to three phase bone scan in evaluating diabetic foot complications?

Background:This paper is based on the initial findings from a prospective ongoing study to evaluate the efficacy of flourodeoxy glucose positron emission tomography-computed tomography (FDG-PET CT) in diabetic foot evaluation.Objective:The aim was to compare the diagnostic accuracies of three phase bone scan (TPBS) and FDG PET-CT (FDG-PET) in diabetic foot evaluation.Methods:Seventy-nine patients with complicated diabetic foot (osteomyelitis/cellulitis, Charcot's neuropathy) were prospectively investigated. TPBS (15 mci methylene di phosphonate [MDP] intravenous [IV]), followed by FDG-PET (5 mci IV) within 5 days were performed in all patients. Based on referral indication, patients grouped into Group I, n = 36, (?osteomyelitis/cellulitis) and Group II, n = 43 (?Charcot's neuropathy). Interpretation was based on intensity, extent, pattern of MDP and FDG uptake (standardized uptake value) along with CT correlation. Findings were compared with final diagnostic outcome based on bone/soft tissue culture in Group I and clinical, radiological or scintigraphic followup in Group II. Results: Group I: For diagnosing osteomyelitis, TP: TN: FP: FN were 14:5:2:2 by FDG PET and 13:02:05:03 by TPBS respectively. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of FDG-PET were 87.5%, 71%, 87.5% and 71% and 81.25%, 28.5%, 72% and 40% for TPBS, respectively. Group II: charcot's: cellulitis: Normal were 22:14:7 by FDG PET and 32:5:6 by TPBS, respectively.Conclusion:Flourodeoxy glucose PET-CT has a higher specificity and NPV than TPBS in diagnosing pedal osteomyelitis. TPBS, being highly sensitive is more useful than FDG-PET in detecting Charcot's neuropathy.

Thyroid incidentalomas discovered on positron emission tomography CT scanning – Malignancy rate and significance of standardised uptake values

AimsIncreasing use of 18F-Fluorodeoxy glucose (FDG) Positron Emission Tomography Computed Tomography (PET CT) has resulted in an increased frequency of incidentally discovered areas of focally increased FDG uptake within the thyroid gland – thyroid incidentalomas. We aimed to compare radiological characteristics of thyroid incidentalomas with cytology, histology and ultrasound findings. Materials and methodsWe examined all FDG PET CT scan reports for all patients undergoing this investigation over a 6 year period in a single tertiary cancer centre. All PET CT scans followed an agreed proforma allowing reports mentioning “thyroid” to be identified. Reports commenting on a positive finding within the thyroid gland were investigated further manually. Incidental mentions of thyroid with no underlying abnormality were discounted from analysis. ResultsIn the study period, 7221 patients underwent FDG PET CT scanning in our unit. Within this group 75 (1%) showed diffuse FDG uptake and 81 (1.1%) showed focal uptake (thyroid incidentalomas). Only 30 patients (37%) with incidentalomas had further investigation and malignancy rate was 23% (7/30). Median Standardised Uptake Values (SUV) in malignant lesions was 9.9 (range 3.5–17.8) whilst in benign lesions and diffuse lesions it was 5.4 (2.8–32) and 4.2 (2.1–25.6) respectively (p = 0.0013, Kruskal Wallis). ConclusionThere remains a need to develop a standardised approach to the investigation and management of thyroid incidentalomas discovered on FDG PET CT scanning. Up to 1 in 4 of these patients will harbour thyroid malignancy.

Bone marrow 18F‐fluoro‐2‐deoxy‐d‐glucose positron emission tomography/computed tomography cannot replace bone marrow biopsy in diffuse large B‐cell lymphoma

This study aimed to investigate whether visual and quantitative (18) F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT)-based bone marrow assessment can replace blind bone marrow biopsy (BMB) in newly diagnosed diffuse large B-cell lymphoma (DLBCL). This retrospective study included 78 patients with newly diagnosed DLBCL who had undergone both FDG-PET/CT and BMB. FDG-PET/CT images were visually evaluated for bone marrow involvement. Patient-based sensitivity of visual FDG-PET/CT assessment was calculated using BMB as the reference standard. Metabolically active volume, maximum standardized uptake value, 3D partial volume corrected mean standardized uptake value, and 3D partial volume corrected mean metabolic volume product (cMVPmean ) of FDG-avid bone marrow lesions were measured. Cox regression analysis was used to determine the influence of (potential) prognostic factors (BMB status, visual [dichotomous] FDG-PET/CT bone marrow status, metabolically active volume, maximum standardized uptake value, 3D partial volume corrected mean standardized uptake value, 3D partial volume corrected mean metabolic volume product, and International Prognostic Index score) on progression-free survival and overall survival. FDG-PET/CT detected bone marrow involvement in 34 (43.6%) cases and BMB in 16 (20.5%) of 78 cases, of whom 11 were also detected by FDG-PET/CT, resulting in a patient-based sensitivity of 68.8% (95% confidence interval = 44.2%-86.1%) for FDG-PET/CT. In the multivariate Cox proportional hazards model, only BMB status was an independent predictive factor of progression-free survival (P = 0.016) and overall survival (P = 0.004). In conclusion, FDG-PET/CT misses bone marrow involvement that has been detected by BMB in a non-negligible proportion of patients. Furthermore, both visual and quantitative FDG-PET/CT-based bone marrow assessments are prognostically inferior to BMB. Therefore, FDG-PET/CT cannot replace BMB in newly diagnosed DLBCL.

Widespread Hypermetabolism in Symptomatic and Asymptomatic Episodes in Kleine-Levin Syndrome

BackgroundNo reliable biomarkers are identified in KLS. However, few functional neuroimaging studies suggested hypoactivity in thalamic and hypothalamic regions during symptomatic episodes. Here, we investigated relative changes in regional brain metabolism in Kleine-Levin syndrome (KLS) during symptomatic episodes and asymptomatic periods, as compared to healthy controls.MethodsFour drug-free male patients with typical KLS and 15 healthy controls were included. 18-F-fluorodeoxy glucose positron emission tomography (PET) was obtained in baseline condition in all participants, and during symptomatic episodes in KLS patients. All participants were asked to remain fully awake during the whole PET procedure.ResultsBetween state-comparisons in KLS disclosed higher metabolism in paracentral, precentral, and postcentral areas, supplementary motor area, medial frontal gyrus, thalamus and putamen during symptomatic episodes, and decreased metabolism in occipital and temporal gyri. As compared to healthy control subjects, KLS patients in the asymptomatic phase consistently exhibited significant hypermetabolism in a wide cortical network including frontal and temporal cortices, posterior cingulate and precuneus, with no detected hypometabolism. In symptomatic KLS episodes, hypermetabolism was additionally found in orbital frontal and supplementary motor areas, insula and inferior parietal areas, and right caudate nucleus, and hypometabolism in the middle occipital gyrus and inferior parietal areas.ConclusionOur results demonstrated significant hypermetabolism and few hypometabolism in specific but widespread brain regions in drug-free KLS patients at baseline and during symptomatic episodes, highlighting the behavioral state-dependent nature of changes in regional brain activity in KLS.

Optical Coherence Tomographic Image of an Angiographically Borderline Lesion With a Significant Fractional Flow Reserve

![Figure][1] [![Graphic][3] ][3][![Graphic][4] ][4] A 42-year-old diabetic woman presented with left ventricular dysfunction late after an anterior wall myocardial infarction. Fluoro-deoxy glucose-positron emission tomography showed viability in the left anterior descending

FDG-PET of Takayasu’s Arteritis

A 71-year-old woman presented with low-grade fever, appetite loss, and weight loss of four months' duration. She had fainted one month earlier during cervical extension and rotation. Physical examination revealed an abdominal aortic bruit and at least a 10 mmHg difference in systolic blood pressure between her arms. Fluorodeoxy glucose-positron emission tomography (FDG-PET) images showed increased FDG uptake in the thoracic aorta, abdominal aorta, as well as the carotid and subclavian arterial branches (Figs. 1 and ​and2).2). Takayasu’s arteritis was diagnosed. All symptoms improved with prednisolone 30 mg/day.

Glucose metabolism measured by positron emission tomography is reduced in patients with white matter presumably ischemic lesions.

BackgroundThe severity and progression of white matter ischemic lesion (WMIL) are closely linked to vascular dementia. The function of neural tissue is closely linked to glucose consumption as the most important energy-supplying metabolic process. At present, 18fluorine-fluorodeoxy glucose (18FDG) positron emission tomography (PET) can provide regional and 3-dimensional quantification of glucose metabolism in the human brain. Although MMSE and MoCA are commonly used screens in cognitive impairment, no research team has yet validated their performance in WMIL. The purpose of our study was to compare MMSE and MoCA in screening for cognitive impairment and to explore the correlations between CMRglu values and executive function.Material/MethodsAll the participants underwent comprehensive clinical, MoCA, MMSE, MRI, and PET examinations. Patients in the WMIL group were subdivided into 3 severity subgroups according to the Fazekas scale.ResultsThe MoCA scores were lower in the WMIL group. Our research indicates that MoCA is a more sensitive screening tool than the commonly used MMSE in detecting cognitive impairment in patients with WMIL. CMRglu values of gray matter were decreased in the WMIL group. Reductions of CMRglu in parietal lobe, frontal lobe, and white matter centrum semiovale were observed to different degrees in the WMIL groups according to the modified Fazekas scale. A significant negative correlation was found between executive function and CMRglu in the frontal lobe.ConclusionsMoCA appears to be a more sensitive screening tool than the commonly used MMSE in detecting cognitive impairment in patients with WMIL. CMRglu can potentially be used as a biomarker for predicting the severity of WMIL.

Usefulness of 2‐[18F]‐fluoro‐2‐deoxy‐d‐glucose–Positron Emission Tomography/Computed Tomography for Staging and Evaluation of Treatment Response in IgG4‐Related Disease: A Retrospective Multicenter Study

To evaluate the usefulness of 2-[18F]-fluoro-2-deoxy-d-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in IgG4-related disease (IgG4-RD) for the staging of the disease and the followup under treatment. All patients included in the French IgG4-RD registry who underwent ≥1 FDG-PET/CT scan were included in the study. Clinical, biologic, pathologic, radiologic, and FDG-PET/CT qualitative and quantitative findings were retrospectively collected and analyzed. Twenty-one patients were included in the study and 46 FDG-PET/CT examinations were evaluated. At either diagnosis or relapse, all evaluated patients presented abnormal 18F-FDG uptake in typical IgG4-RD localizations. In most cases, FDG-PET/CT was more sensitive than conventional imaging to detect organ involvement, especially in arteries, salivary glands, and lymph nodes. In few cases (small-sized lesions and brain or kidney contiguous lesions), false-negative results were noted. Evaluation before and after treatment showed in most cases a good correlation of FDG-PET/CT results with treatment response and disease activity. This large retrospective study shows that FDG-PET/CT imaging is useful for the staging of IgG4-RD. Moreover, FDG-PET/CT is useful to assess the response to treatment during followup.

Re-Evaluation of Clinical Dementia Diagnoses with Pittsburgh Compound B Positron Emission Tomography

Objectives: There is an overlap regarding Pittsburgh compound B (PIB) retention in patients clinically diagnosed as Alzheimer's disease (AD) and non-AD dementia. The aim of the present study was to investigate whether there are any differences between PIB-positive and PIB-negative patients in a mixed cohort of patients with neurodegenerative dementia of mild severity regarding neuropsychological test performance and regional cerebral glucose metabolism measured with [¹⁸F]fluoro-2-deoxy-<smlcap>D</smlcap>-glucose (FDG) positron emission tomography (PET). Methods: Eighteen patients clinically diagnosed as probable AD or frontotemporal dementia were examined with PIB PET, FDG PET and neuropsychological tests and followed for 5-9 years in a clinical setting. Results: The PIB-positive patients (7 out of 18) had slower psychomotor speed and more impaired visual episodic memory than the PIB-negative patients; otherwise performance did not differ between the groups. The initial clinical diagnoses were changed in one third of the patients (6 out of 18) during follow-up. Conclusions: The subtle differences in neuropsychological performance, the overlap of hypometabolic patterns and clinical features between AD and non-AD dementia highlight the need for amyloid biomarkers and a readiness to re-evaluate the initial diagnosis.

Clinical application of 18F‐fluoro‐2‐deoxy‐D‐glucose positron emission tomography/computed tomography in breast cancer

Positron emission tomography (PET)/computed tomography (CT) is not suited for primary diagnostics of breast tumours and it cannot replace sentinel lymph node technique in determining metastases to the axilla. PET/CT has a high sensitivity and specificity regarding the detection of loco-regional recurrence and metastases to mediastinal and internal mammary lymph nodes, as well as distant metastases. Whether the method can replace conventional methods, or be a supplement when this is non-conclusive, remains unresolved. PET/CT cannot be recommended for routine follow-up but is recommended in patients with suspected relapse when conventional imaging has given equivocal results. PET/CT can be applied to confirm isolated loco-regional relapse or metastatic lesion detected by conventional imaging. PET/CT has a high sensitivity for detecting response to treatment, but a low specificity calls for cautions. Further investigations into the use of PET/CT to predict and monitor response are warranted, before this approach may find its way into a clinical setting. In the future, PET/CT will probably find increasing use in treatment planning and evaluation of patients with breast cancer.

Aerobic glycolysis in the primate brain: reconsidering the implications for growth and maintenance

Glucose metabolism produces, by oxidative phosphorylation, more than 15 times the amount of energy generated by aerobic glycolysis. Nonetheless, aerobic glycolysis remains a prevalent metabolic pathway in the brain. Here we review evidence suggesting that this pathway contributes essential molecules to the biomass of the brain. Aerobic metabolism is the dominant metabolic pathway during early postnatal development when lipids and proteins are needed for the processes of axonal elongation, synaptogenesis, and myelination. Furthermore, aerobic metabolism may continue into adulthood to supply biomolecules for activity-related changes at the synapse and turnover of constituent structural components of neurons. Conversely, oxidative phosphorylation appears to be the main metabolic support for synaptic transmission, and, therefore, this pathway seems to be more dominant in brain structures and at time points in the lifespan that are characterized by increased synaptic density. We present the case for differing relationships between aerobic glycolysis and oxidative phosphorylation across primates in association with species-specific variation in neurodevelopmental trajectories. In doing so, we provide an alternative interpretation for the assessment of radiolabeled glucose positron emission tomography studies that regularly attribute increases in glucose uptake to neural activity alone, and propose a new model for the contribution of metabolic pathways for energetic demand and neural tissue growth. We conclude that comparative studies of metabolic appropriation in the brain may contribute to the discussion of human cognitive evolution and to the understanding of human-specific aging and the etiology of neuropsychiatric diseases.