SPECT-scans

Figure 13.1. The brain in Alzheimer s disease. The figure on the left is a static MRI scan, where marked cortical atrophy is evident. The right-hand figure is a SPECT scan showing impoverished metabolism in the Alzheimer brain.

DeKosky, S. T., Shih, W. J., Schmitt, F. A et al. Assessing utility of single photon emission computed tomography (SPECT) scan in Alzheimer disease correlation with cognitive severity. Alzheimer Dis. Assoc. Disord. 4 14—23,1990. 

The most recent SPECT scan (single photon computed tomography of the brain) studies, by a Harvard School of Public Health physician and researcher, have shown that people with MCS have blood flow patterns in the brain that are different from those of healthy controls and from people with Chronic Fatigue Syndrome.4... 

Hu, Howard, M.D., M.P.H., ScD., Associate Professor, Harvard School of Public Health, SPECT Scans and MCS, presentation at a University of Washington and Washington State Department of Labor and Industry conference, Chemicals, the Environment and Disease A Research Perspective, May 7, 1999, Seattle, Washington. 

L. Matthews. Jefferson, NC McFarland, 1998. Contains chapters written by a psychologist, an attorney and two physicians with expertise in MCS. A medical section addresses porphyria, SPECT scan studies, and psychological issues related to MCS. A legal section discusses how one state s workers compensation system fails workers in a toxic age. A personal section discusses the author s experience in the workers compensation system science and the literature is addressed in yet another section. 

Frmctional imaging such as PET scanning and SPECT scanning is also likely to be explored for detecting early activity of these cytostatic agents just as PET scanning documented the early activity of Gleevec in patients with G1 stromal tumors. ... 

Two Californian physicians, Daniel Amen and Blake Carmichael, have used another radiological technique— single photon emission computed tomography (SPECT) scanning—on more than 2,000 patients, including adolescents and children. This process, which uses less radiation... 

Figure 3.1 Although no biological cause has yet been found for ADHD, some scientists have offered studies using PET and SPECT scans that may demonstrate a link between ADHD-type behavior and decreased blood flow in the prefrontal cortex of the brain. This diagram of the brain shows the cerebral cortex—the area that some researchers posit may be connected to ADHD.

More recently, the same authors extended their patient follow up to six and 12 months and attempted to stratify the magnitude of improvement by progenitor cell characteristics, that is, elucidate the potential mechanism of improvement (43). The BNP levels increased in both groups but not as markedly in the treatment group (BNP 507 vs. 740 at 12 months P = 0.08). There was a persistent favorable difference in the NYHA class (2.7 vs. 1.4 P = 0.01) and exercise tolerance (METs 7.2 vs. 5.1 P = 0.02). There was no longer a difference in the EF between the two groups however, the size of the reversible defect on repeat SPECT scans at 12 months was markedly smaller in the treated group (I I % vs. 34% P = 0.01). Monocyte and early hematopoietic cell... 

Environmental health specialists can use a great number of research methods to ascertain the presence of MCS, partially due to the diversity among symptoms and partially because of the fact that the whole body is alfected by MCS. The tests concern, among other things, blood and urine samples, allergy and skin tests, SPECT-scans, biopsies, and neuro-cognitive tests. Below you can find three websites which report extensively on the employed methods and the results of studies. 

SPECT scans have demonstrated that a decrease in blood circulation in the brain of some MCS patients occurs when these patients are exposed to substances like perfume. See an example at www.ourlittleplace.com/spect.html. 

The authors thought that the abnormal SPECT scan was best explained by reduced cerebral blood flow due to vasoconstriction, which could have been due to ecstasy-induced reduction in serotonin. 

Ciclosporin-induced vasculopathy, with endothelial injury and derangement of the blood-brain barrier, is the postulated mechanism of neurological damage. Transient cerebral perfusion abnormalities, demonstrable in SPECT scans of the brain, have been suggested as a reliable indicator of ciclosporin neurotoxicity (SEDA-20, 344). Clinical symptoms as well as CT and/or MRI scans were very similar to those observed in hypertensive encephalopathy, with predominant and reversible white-matter occipital lesions (23). There was complete neurological recovery in most patients after blood pressure was normalized, and deaths due to intracranial hemorrhage are reported only exceptionally. 

The complexity of the entire nervous system can be overwhelming however, having some general information is helpful. Let s begin by taking a look at the central nervous system and in particular the brain. Advances in the neurosciences, especially newer neuro-imaging techniques (such as MRI, PET, and SPECT scanning), have allowed researchers to identify more precisely which brain structures are im-... 

SPECT scans measure radiotracer uptake by tissues and provide cross-sectional images of the brain. This technique has been used extensively to assess cerebral blood flow. Although the resolution of SPECT is not as good as PET, the availability has led to wide clinical use in disorders such as stroke, dementia, and epilepsy. 

Henry 2000 Myocardial ischemia CAD, not amenable to revascularization VEGF 165 protein Intracoronary administration Phase 1 2 mo Improved SPECT scan results, decreased angina in 13/15 patients... 

Vale 1999 Myocardial ischemia Symptomatic CAD, not amenable to revascularization Naked plasmid VEGF 165 Intramyocardial injection via electromechanical catheter Phase 1 90 days Significant reduction in angina and NTG use improved SPECT scan... 

Highly selective 5-HT uptake inhibitors considered not suitable for clinical use are often excellent tools for the in vivo imaging of central 5-HT transporters in health and disease by PET or SPECT scan methods. 

At least one study has shown that SPECT scanning, with its 3D resolution, gave a statistically significant improvement in the accuracy of assessing central... 

As mentioned previously, the use of SPECT scanning has, in some smdies, improved resolution when compared with conventional planar scanning but the increased dose and complexity involved makes it debatable whether these techniques can be justified routinely in children. This may change with improved equipment. A further technical problem with SPECT is that the relatively long acquisition time causes problems with radionuclides such as c-sodium pertechnetate that are rapidly cleared from the lungs and subsequently appear in the pulmonary circulation. 

Payne WK, Ogilvie JW (1996) Back pain in children and adolescents. Pediatr Clin North Am 43 899-917 Pickett WJ, Faleski EJ, Chacko A, Jarrett RV (1983) Comparison of radiographic and radionuclide skeletal surveys in battered children. South Med J 76 207-212 Read MTS (1994) Single photon emission computed tomography (SPECT) scanning for adolescent back pain. Br J Sports Med 28 56-57... 

Nervous system Intravenous acetazolamide 1 g can cause transient ischemic attacks when it is used in a test of clinically significant cerebral artery stenosis In this test, a cerebral SPECT scan is performed before and after intravenous administration of acetazolamide 1 g. Acetazolamide causes cerebral vasodilatation, leading to relative hypoperfusion (steal effect) in compromised circulation. This hypoperfusion can cause a transient ischemic attack. In one series, three of 105 patients had transient ischemic attacks after administration of acetazolamide. 

Figure 3.8 SPECT imaging of two patients with histologically confirmed lung cancer using "Tc-sestamihi. In one patient, an early SPECT scan after " Tc-sestamibi injection shows intense tumor uptake (a) (arrow) that is significantly decreased after a delayed scan (h). This suggests rapid washout of Tc-sestamibi and low expression of Pgp. In contrast, the other patient shows intense tumor uptake of Tc-sestamibi after an early SPECT scan (c) that does not decrease by the time of the delayed scan (d) suggesting a low level of Pgp expression. The expression levels were subsequently confirmed by immunohistochemistry on tumor biopsies. Tbis study demonstrates the ability to image the transmembrane Pgp that has utility for predicting response to chemotherapy and efficacy of Pgp modulators. Reproduced with permission from Ref. (127).

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