Contribution of FDG to Modern Medicine, Part I, An Issue of PET Clinics (eBook)

Soren Hess (Autor)

eBook Download: PDF | EPUB

2014 | 1. Auflage
100 Seiten
Elsevier Health Sciences (Verlag)
978-0-323-32627-8 (ISBN)

Infos

This issue of PET Clinics examines the Contribution of FDG to Modern Medicine. In the first of two issues, articles include: The Basic Principles of FDG-PET/CT Imaging; FDG-PET in Diffuse Large B-cell Lymphoma; FDG-PET in Thoracic Malignancies; FDG-PET/CT in Gastrointestinal Malignancies; FDG-PET/CT in Infectious and Inflammatory Diseases; FDG in Urologic Malignancies; FDG-PET for Interventional Oncology in Liver Malignancy; FDG-PET in Neurology and Psychiatry, and more!

Textauszug

Fluorodeoxyglucose PET in Neurology and Psychiatry

Michael Schöll, PhDab∗ [e-mail], Andrés Damián, MDc and Henry Engler, MD, PhDcd,     aMedTech West and the Department of Clinical Neuroscience and Rehabilitation, University of Gothenburg, Blå stråket 5, 6th Floor, Gothenburg 413 45, Sweden; bDepartment NVS, Center for Alzheimer Research, Translational Alzheimer Neurobiology, Karolinska Institute, Novum 5th Floor, Stockholm 14186, Sweden; cUruguayan Centre of Molecular Imaging (CUDIM), Av. Dr. Américo Ricaldoni 2010, Montevideo 11600, Uruguay; dDepartment of Medical Sciences, Uppsala University, Box 256, Uppsala 75105, Sweden

∗Corresponding author. MedTech West, Sahlgrenska University Hospital, Blå stråket 5, 6th Floor, Gothenburg 413 45, Sweden

PET imaging with the most widely available PET tracer, 2-deoxy-2-[18F]fluoro-d-glucose (FDG), is a powerful tool in the differential diagnosis of numerous neurologic and psychiatric disorders, particularly in early disease stages. It also plays an important role in the longitudinal evaluation of treatment effects and the depiction of disease courses. A selection of established and eligible application areas of FDG PET in neurology and psychiatry, such as different types of dementia, epilepsy, schizophrenia, and bipolar disorder, are reviewed in this article. A general methodology for clinical FDG PET examinations and typical diagnostic criteria and pitfalls are addressed.

Keywords

Fluorodeoxyglucose positron emission tomography

[18F]-Fluorodeoxyglucose

Neurology

Psychiatry

Dementia

Key points

• Molecular imaging with [18F]fluoro-d-deoxyglucose (FDG) PET can assist in the differential diagnosis of neurologic and psychiatric disorders, particularly in their early stages.

• FDG PET has the potential to describe the course of neurologic and psychiatric disease.

• Pitfalls should be known by nuclear medicine physicians to obtain a correct diagnosis.

• Combining FDG PET with a recent magnetic resonance image and performing integrated multimodality interpretation can add important complementary information.

• The combination of FDG with other PET tracers can enhance accuracy in differential diagnoses.

Introduction

The synthesis of 2-deoxy-2-[18F]fluoro-d-glucose (FDG) at the Brookhaven National Laboratory in 1976 was a groundbreaking development in nuclear medicine imaging.1

FDG has developed since then into the most widely available tracer for PET and is used extensively in clinical and research settings.

The first application of FDG PET in humans was to measure glucose metabolism in the brain,2 and although most clinical FDG PET examinations are performed in oncology, its application in the assessment of disorders of the central nervous system (CNS) is of cardinal importance.

In neurology and psychiatry, focal lesions in the highly plastic CNS can lead to complex symptoms, and neuroimaging by means of computed tomography (CT) and magnetic resonance (MR) imaging plays an important role in the in vivo detection of structural lesions. However, it was with the advent of PET that the ability was provided to understand the underlying molecular mechanisms that often precede structural changes, allowing an early diagnosis as well as targeted treatment management based on functional rather than structural measures.

The great diversity of existing PET tracers allows the study of numerous brain functions in normal and pathologic conditions, such as the measurement of regional blood flow, glucose metabolism, enzyme activity, protein accumulation, or receptor density in the CNS. However, in this article, the focus is on selected established and eligible applications of FDG PET in neurology and psychiatry (Box 1).

Box 1   Indications for FDG PET in neurology and psychiatry

• Dementia: assessment of patients with symptoms of dementia. Early diagnosis of dementia. FDG PET can be useful in the differential diagnosis between different dementing disorders including Alzheimer disease, dementia with Lewy bodies, frontotemporal lobe dementia, and vascular dementia.

• Epilepsy: FDG PET is useful in the presurgical evaluation of refractory epilepsy to lateralize and localize the functionally impaired region, especially in patients with normal MR imaging findings.

• Parkinsonian disorders: differential diagnosis of parkinsonisms. FDG PET is useful in the evaluation of Parkinson disease, and in the diagnosis of atypical parkinsonisms, including corticobasal degeneration, multiple system atrophy, and progressive supranuclear palsy.

• Psychiatry: FDG PET has been proved useful in the study of patients with psychiatric disorders such as depression, bipolar disorder, and schizophrenia.

• Stroke and assessment of neuronal plasticity.

Imaging technique

The technical aspects of FDG PET and its application are covered in the article “The basic principles of FDG-PET/CT imaging” in this issue and are thus only sketchily described here.

FDG PET in the study of the CNS is safe for the patient and a straightforward procedure, which generally is as follows (for European Association for Nuclear Medicine [EANM] guidelines, see Ref.3): the patient does not need any preparation except for at least 4 hours of fasting and abstention from coffee, tea, alcohol, and nicotine, and in case of diabetes, normalization of glycemia. A dose of approximately 3.0 MBq/kg (Box 2 for detailed information) of FDG is administered intravenously once the patient is in a condition of neurosensory relaxation, lying on a bed in a dimmed room with eyes closed and no external auditory stimuli. If a patient is unable to cooperate, mild sedation may be used shortly before image acquisition. After 30 to 60 minutes under these conditions, images are acquired with the patient supine and the head stabilized in the center of the field of detection. In three-dimensional acquisition mode of modern PET scanners, offering a spatial resolution of 3 to 6 mm, a static emission scan commonly lasts about 30 minutes, including transmission scans for tissue attenuation correction, whereas dynamic imaging, meaning the collection of a temporal series of frames, can last up to 90 minutes. In addition to studies of resting state, acquisition can also be performed in the course of a pharmacologic or cognitive stimulation.

Box 2   Image acquisition protocols for FDG PET

Recommended FDG PET patient preparation and image acquisition:

• Patient preparation: fasting for 4 to 6 hours. Measure of blood glucose level before FDG injection (low-quality images can be expected with blood glucose levels higher than 160 mg/dL). Patient positioning in a quiet area 15 minutes before FDG injection and during the established uptake period, especially in the first minutes. Intravenous cannulation 15 minutes before tracer injection. Bladder voiding before FDG administration and acquisition.

• Injection: 185 to 740 MBq in adults (typically 300–600 MBq in 2D mode, 125–250 MBq in 3D mode).3,161 In children refer to the European Association of Nuclear Medicine dosage card v.1.5.2008, (class B radiotracer). Effective dose: 19 μSv/MBq in adults. Highest absorbed dose in bladder: 0.13–0.16 mGy/MBq in adults.

• Positioning: patients should be instructed to avoid or minimize head movements. Head fixation may be useful. The orbitomeatal line in parallel to the detector rings can be used for standardization of the positioning.

• Acquisition: attenuation correction can be performed with CT. Inspect images to detect patient motion between CT and PET acquisition. Standardized acquisition times after injection (eg, 30, 40, or 60 minutes after FDG administration). List mode acquisition and dynamic acquisition with short frames can be useful for movement corrections. Reconstruction with ordered-subsets expectation maximization or filtered back projection.

• Quantification: semiquantitative analysis comparing patients with age-matched normal control individuals can be used to assist visual analysis. Standardized uptake values (SUVs) help in the assessment of uptake patterns. Ideally, SUV ratios are created using an unaffected reference region. Quantification of CMRglc can be performed using arterial or arterialized blood input....

Produkt-Details

• Erscheint lt. Verlag: 1.10.2014
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie ► Gesundheitsfachberufe
• Themenwelt: Medizinische Fachgebiete ► Radiologie / Bildgebende Verfahren ► Computertomographie
• Themenwelt: Medizinische Fachgebiete ► Radiologie / Bildgebende Verfahren ► Radiologie
• ISBN-10: 0-323-32627-7 / 0323326277
• ISBN-13: 978-0-323-32627-8 / 9780323326278