Single photon emission computerized tomography (SPECT) in detecting neurodegeneration in Huntington's disease.

Single photon emission computerized tomography (SPECT) studies were performed on 34 manifest Huntington's disease (HD) patients at various stages of clinical pathology ranging from early chorea to late dystonia with or without signs of dementia and 12 pre-symptomatic patients with abnormal terminal CAG expansions. Thirty HD patients with obvious clinical signs and seven pre-symptomatic patients without signs or symptoms of HD displayed selective caudate hypoperfusion by direct visual inspection. Such qualitative, selective striatal hypoperfusion patterns can be indicative of early and persistent metabolic changes in striatal neuropathology. SPECT studies can be useful in documenting early pre-clinical changes in patients with abnormal terminal CAG expansions and in confirming the presence of caudate pathology in patients with clinical signs of HD.     

Clinical value of combined single photon emission computerized tomography and conventional computer tomography (SPECT/CT) in sports medicine

Integrated hybrid single photon emission computerized tomography (SPECT)/computer tomography (CT) is a promising new diagnostic imaging modality for orthopedic patients. A high diagnostic yield is available from combining the detection of abnormal bone metabolism with SPECT, to the precise anatomical detail available in high resolution CT. With this review, we endeavor to illustrate the clinical value and future perspectives of SPECT/CT in sports medicine.     

123I-IMP single photon emission computed tomography (SPECT) study in childhood epilepsy

N-isopropyl-p[123I]-iodoamphetamine (IMP) single photon emission computed tomography (SPECT), X-ray computed tomography (X-CT) and magnetic resonance imaging (MRI) were performed in 18 children with idiopathic seizures. In children with idiopathic seizures SPECT identified abnormal lesions in the highest rate (50%) compared with X-CT (11%) and MRI (13%), but the findings of SPECT poorly correlated with the foci on electroencephalography (EEG). Idiopathic epilepsy with abnormal uptake on SPECT was refractory to medical treatments and frequently associated with mental and/or developmental retardation. Perfusion defects identified on SPECT probably influenced the development of the brains in children. IMP SPECT is useful in the diagnosis and medical treatment in children with seizures.     

Definition of hepatic tumor microcirculation by single photon emission computerized tomography (SPECT)

Single photon emission computerized tomography coupled with Tc-99m MAA hepatic-arterial perfusion scintigraphy has been used to examine the density of the functional microcirculation of hepatic tumors relative to normal liver in 24 patients. In both colorectal and carcinoid tumors we have demonstrated an average three-fold greater arteriolar-capillary density in areas of tumor proliferation. The depth of the evoked tumor hypervascularity was found to extend about 4 cm. Tumors greater than 8-9 cm in diameter were uniformly found to have a central hypovascular core. These observations are of importance in the design of selective strategies utilizing therapeutic microspheres directed against the hypervascular proliferating regions of human tumors.     

Role of positron emission tomography (PET) and single photon emission tomography (SPECT) in so-called "multiple chemical sensitivity"

Functional imaging with SPECT and PET is increasingly used to prove evidence for the existence of a syndrome "Multiple Chemical Sensitivity" (MCS) and plays a major role in legal trials to justify compensation for the exposure to solvents. This paper critically reviews the literature on the use of SPECT and PET for the determination of MCS. The authors come to the conclusion that the current data are not sufficient to justify the claim of the existence of such a syndrome. The low specificity of the observed PET and especially SPECT-findings makes it very difficult to establish a cause-result relationship and therefore makes the use of these methods in legal trials on this issue doubtful.     

The role of single photon emission computed tomography in bone scintigraphy

The increasing availability for routine nuclear medicine studies of single photon emission computed tomography (SPECT) reflects the realisation of its ability to improve lesional detection and the assessment of location. This is achieved by removing unwanted surrounding radioactivity and thus delineating with greater clarity deeper areas of preferential accumulation. By removing the superimposition of structures, SPECT offers considerable potential for improved diagnostic accuracy in suspected bone and joint disease. Time and cost, however, necessitate a selective use of the technique. The maximum advantages arise from studies of the head, spine, skull and knees. The role of SPECT does, in some instances, lie in providing increased sensitivity in the detection of focal uptake while in others it complements alternative imaging modalities by identifying the functional status of an abnormality and thus may demonstrate its clinical significance. Since such information may be obtained by planar scintigraphy using techniques such as pinhole collimation, continuing evaluation is essential to ascertain the precise indications for SPECT imaging.Based on a presentation at the 15th Annual Meeting of the International Skeletal Society, Sydney, Australia, September 1988     

A comparative study of attenuation correction algorithms in single photon emission computed tomography (SPECT)

A computer based simulation method was developed to assess the relative effectiveness and availability of various attenuation compensation algorithms in single photon emission computed tomography (SPECT). The effect of the nonuniformity of attenuation coefficient distribution in the body, the errors in determining a body contour and the statistical noise on reconstruction accuracy and the computation time in using the algorithms were studied. The algorithms were classified into three groups: precorrection, post correction and iterative correction methods. Furthermore, a hybrid method was devised by combining several methods. This study will be useful for understanding the characteristics, limitations and strengths of the algorithms and searching for a practical correction method for photon attenuation in SPECT.     

A comparative study of attenuation correction algorithms in single photon emission computed tomography (SPECT)

A computer based simulation method was developed to assess the relative effectiveness and availability of various attenuation compensation algorithms in single photon emission computed tomography (SPECT). The effect of the nonuniformity of attenuation coefficient distribution in the body, the errors in determining a body contour and the statistical noise on reconstruction accuracy and the computation time in using the algorithms were studied. The algorithms were classified into three groups: precorrection, post correction and iterative correction methods. Furthermore, a hybrid method was devised by combining several methods. This study will be useful for understanding the characteristics, limitations and strengths of the algorithms and searching for a practical correction method for photon attenuation in SPECT.     

Hepatic vein dilatation as seen on single photon emission computed tomography (SPECT) of the liver

An area of photon deficiency in both planar and single photon emission computed tomography (SPECT) images of the liver using 99mTc-Sulfur Colloid was found to be due to a dilated hepatic vein.     

Hepatic vein dilatation as seen on single photon emission computed tomography (SPECT) of the liver

An area of photon deficiency in both planar and single photon emission computed tomography (SPECT) images of the liver using ^99mTc-Sulfur Colloid was found to be due to a dilated hepatic vein.     

Quantitative analysis in single photon emission tomography (SPET)

Quantitative analysis can improve the sensitivity and specificity of single photon emission tomography (SPET) procedures, as well as reduce inter- and intraobserver variabilities. Quantification of the radioactivity distribution is the ultimate goal of SPCT. In this review we consider the basic requirements for an optimum three-dimensional reconstruction of the radionuclide distribution to enable quantification. Attenuation and scatter correction as well as varying resolution are the major problems. In the older SPET systems quantification was hampered by the lack of system sensitivity and sufficient computer power. Therefore, the imaging system was often assumed to be shift invariant and linear and the attenuation throughout the object uniform. More sophisticated solutions have been proposed and with more or less success implemented, but not for application in daily practice. Knowledge (measurement) of the attenuation is often required. New generation SPET systems employing multi-detectors and super minicomputers will ease the implementation of these solutions. Offprint requests to: J.A.K. Blokland     

A low-cost phantom for simple routine testing of single photon emission computed tomography (SPECT) cameras

A simple sphere test phantom has been developed for routine performance testing of SPECT systems in situations where expensive commercial phantoms may not be available. The phantom was based on a design with six universal syringe hubs set in the frame to support a circular array of six glass blown spheres of different sizes. The frame was then placed into a water-filled CT abdomen phantom and scanned with a triple head camera system (Philips IRIX™, USA). Comparison was made with a commercially available phantom (Deluxe Jaszczak phantom).Whereas the commercial phantom demonstrates cold spot resolution, an important advantage of the sphere test phantom was that hot spot resolution could be easily measured using almost half (370 MBq) of the activity recommended for use in the commercial phantom. Results showed that the contrast increased non-linearly with sphere volume and radionuclide concentration. The phantom was found to be suitable as an inexpensive option for daily performance tests.