Comparison of Different Methods for Attenuation Correction in Brain PET: Influence on the Calculation of the Metabolic Glucose Rate

The EANM practice guidelines for bone scintigraphy

PURPOSE

The radionuclide bone scan is the cornerstone of skeletal nuclear medicine imaging. Bone scintigraphy is a highly sensitive diagnostic nuclear medicine imaging technique that uses a radiotracer to evaluate the distribution of active bone formation in the skeleton related to malignant and benign disease, as well as physiological processes.

METHODS

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines to promote the use of nuclear medicine procedures of high quality.

CONCLUSION

The present guidelines offer assistance to nuclear medicine practitioners in optimizing the diagnostic procedure and interpreting bone scintigraphy. These guidelines describe the protocols that are currently accepted and used routinely, but do not include all existing procedures. They should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary.

EANM procedure guidelines for PET brain imaging using [18F]FDG, version 2

These guidelines summarize the current views of the European Association of Nuclear Medicine Neuroimaging Committee (ENC). The purpose of the guidelines is to assist nuclear medicine practitioners in making recommendations, performing, interpreting, and reporting the results of fluorine-18 fluoro-2-deoxyglucose ([(18)F]FDG) PET imaging of the brain. The aim is to help achieve a high standard of FDG imaging, which will increase the diagnostic impact of this technique in neurological and psychiatric practice. The present document replaces a former version of the guidelines that were published in 2002 [1] and includes an update in the light of advances in PET technology, the introduction of hybrid PET/CT systems and the broadening clinical indications for FDG brain imaging. These guidelines are intended to present information specifically adapted for European practice. The information provided should be taken in the context of local conditions and regulations.

Evaluation of a new expert system for fully automated detection of the Alzheimer's dementia pattern in FDG PET

OBJECTIVE

Fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used to support a diagnosis of Alzheimer's disease. The aim of the present study was to evaluate a new expert system (PALZ) for the fully automated analysis of FDG PET images for diagnosis of the disease.

METHODS

The PALZ tool is based on the detection of the typical disease pattern in FDG PET images. Its potential for this task was evaluated in 22 consecutive patients with suspected Alzheimer's disease who had been graded as positive for the pattern by an experienced reader (visual analysis supported by statistical parametric mapping (SPM)), and in 18 controls. Dependence on scanner performance was assessed by variation of the spatial resolution of the PET images.

RESULTS

All the Alzheimer's disease subjects were classified as pattern-positive by the PALZ tool. Fifteen controls were classified as normal. Sensitivity and specificity for differentiation of the patients with suspected Alzheimer's disease from the controls were 100% and 83%, respectively. The false positive finding in three controls most likely was caused by differences in attenuation correction between the normal data base of the PALZ tool (cold transmission scan) and the local data sets (hot transmission scan). There was only mild dependence on spatial resolution.

CONCLUSIONS

The results of the present study suggest that the PALZ tool provides similar performance for the detection of the typical Alzheimer's disease pattern in FDG PET images as an experienced reader supported by SPM. The PALZ tool is fully automated, easy to use, and insensitive to the spatial resolution of the PET scanner used. Therefore, it has the potential for widespread clinical use.

Strategies for attenuation compensation in neurological PET studies

Molecular brain imaging using positron emission tomography (PET) has evolved into a vigorous academic field and is progressively gaining importance in the clinical arena. Significant progress has been made in the design of high-resolution three-dimensional (3-D) PET units dedicated to brain research and the development of quantitative imaging protocols incorporating accurate image correction techniques and sophisticated image reconstruction algorithms. However, emerging clinical and research applications of molecular brain imaging demand even greater levels of accuracy and precision and therefore impose more constraints with respect to the quantitative capability of PET. It has long been recognized that photon attenuation in tissues is the most important physical factor degrading PET image quality and quantitative accuracy. Quantitative PET image reconstruction requires an accurate attenuation map of the object under study for the purpose of attenuation compensation. Several methods have been devised to correct for photon attenuation in neurological PET studies. Significant attention has been devoted to optimizing computational performance and to balancing conflicting requirements. Approximate methods suitable for clinical routine applications and more complicated approaches for research applications, where there is greater emphasis on accurate quantitative measurements, have been proposed. The number of scientific contributions related to this subject has been increasing steadily, which motivated the writing of this review as a snapshot of the dynamically changing field of attenuation correction in cerebral 3D PET. This paper presents the physical and methodological basis of photon attenuation and summarizes state of the art developments in algorithms used to derive the attenuation map aiming at accurate attenuation compensation of brain PET data. Future prospects, research trends and challenges are identified and directions for future research are discussed.