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Eight patients with drug-resistant complex-partial seizures were subjected to left- and right-sided intracarotid sodium amytal (ISA) procedures during preoperative investigations for surgical treatment. Regional changes of cerebral and cerebellar blood flow during barbiturization were measured by [99mTc]-HMPAO-SPECT. Crossed cerebellar diaschisis (CCD) was observed in 13 out of 16 tests (81%) as well as ipsilateral cerebral hypoperfusion (87%). Thus CCD occurred more frequently in ISA procedures than in previously studied patients with cerebral infarctions and tumors. Since intracarotid injections of sodium amytal lead to hypoperfusion mainly in those areas of the brain that are supplied by the middle cerebral artery, functional suppression of these regions is supposed to be one of the main preconditions of CCD. Our findings suggest that CCD as demonstrated by the SPECT-technique is a common phenomenon in ISA procedures.

Objective: The aim of this study was to evaluatel-3[123I]-iodo-α-methyl tyrosine (IMT)-SPECT and FDG-PET in pulmonary lesions suspected to be lung cancer.Methods: Whole body PET (measured transmission corrected emission scans) was performed 45 minutes after i.v. injection of 222–370 MBq (6–10 mCi)18F-FDG on a Siemens PET scanner (ECAT EXACT 47) including 5–6 bed positions.123I-IMT-SPECT (chest) was performed after injection of 370 MBq (10 mCi) with a dual head camera (Picker Prism 2000) and commercially available reconstruction algorithms. Ten patients (6 male and 4 female) with suspected lung cancer were investigated. The results were compared to histological findings after surgery or bronchoscopic biopsies and CT.Results:123I-IMT-SPECT and FDG-PET were able to detect all 9 cases of lung cancer (1–8 cm in diameter). One case was true negative. Both imaging methods were true positive with respect to mediastinal lymph node metastases in one patient. The tumor/background ratio was higher with PET (8.20vs. 2.84).Conclusion: Despite the limited number of patients it may be concluded that IMT-SPECT as well as FDG-PET are suited to correctly diagnose lung cancer. Nevertheless, FDG-PET, if available, seems to be better suited because of the higher tumor/background ratio and better resolution.

Therapeutic means for patients with painful bony metastases are strongly limited. In these patients, a systemic therapy with isotopes can be helpful. The aim of this study was to evaluate the efficacy of rhenium-186 HEDP for pain palliation in patients with disseminated bone metastases.30 patients taking analgesics because of bone pain received one or more injection of 1295 MBq 186Re HEDP for pain palliation.In 70% of the patients, therapy resulted in a significant reduction of pain. The average duration of pain relief was 4 weeks (1 week-2.5 months). The main side effects of therapy were a decrease of platelets (aver. 30000/microliters) and an increase of pain for 1-2 days (flare-phenomenon).Therapy with rhenium-186 HEDP can be used complementarily to analgesic therapy in patients with painful, disseminated bone metastases.

Brain single photon emission computed tomography (SPECT) was performed in 16 patients with focal epilepsy, as well as EEG, using 99m Tc-HM-PAO SPECT and a rotating gamma camera system. Pathological Tc-HM-PAO SPECT findings were registered in 75%. CT was positive in 25%. MRI was positive in 76%. The results of Tc-HM-PAO SPECT findings were compared with those of CT and MRI. 61% of the MRI findings correlated with the pathological SPECT findings with respect to the side of the hemisphere, and in 75% of the patients the focal EEG abnormality and the pathological Tc-HM-PAO-SPECT findings were localized in the same hemisphere.

Amphetamine is stored by brain tissue and permits its scintigraphic imaging, particularly with the single-photon emission computed tomography (SPECT). A total of 60 scintigraphic investigations in 54 patients were done. Investigations were done using an emission computed tomograph (rotating gamma-camera) after application of 123I-N-isopropyl-amphetamine. In 6 out of 24 patients with epilepsy a focus in agreement with EEG findings could be established despite negative cranial computed tomography (CT). In 4 out of 25 patients with cerebrovascular disease diminished perfusion was demonstrated although cranial CT was normal. In 10 out of 20 cases the extent of functional lesions demonstrated by SPECT was larger than could be assumed by cranial CT findings. Three patients with migraine and negative CT findings showed disorders of perfusion in the amphetamine-SPECT which were in agreement with the EEG. Brain SPECT using 123I-labelled amphetamines thus offers the possibility to demonstrate functional perfusion and metabolic disorders which show no morphologic correlate in the cranial CT. In addition, foci demonstrated in cranial CT can be more precisely defined in their functional extent using the SPECT.

The lipophilic brain SPECT agent [99mTc]hexamethyl propylene amine oxime (HM-PAO) was used in three cases before and during unilateral anesthesia of one hemisphere for lateralization of speech dominance (Wada test). This procedure led to a decrease of regional cerebral blood flow (rCBF) in each of the hemispheres to 55 and 90%, respectively. Diminution of rCBF was significantly more pronounced in the dominant hemisphere. A second phenomenon observed during the Wada test was crossed cerebellar diaschisis. These findings support the assumption that HM-PAO allows monitoring of brain perfusion, as rapid changes of rCBF due to decreased neuronal activity cause respective alterations of cerebral and cerebellar uptake of this new brain agent.

Derivatives of propylene-amine-oxime (PnAO) have been synthesized which form a neutral lipid-soluble complex with 96mTc and can be supplied as freeze-dried kits. The complexes cross the intact blood-brain barrier. This report shows the brain uptake, early kinetics and biodistribution in normal adult baboons of 5 99mTc-PnAO derivatives and 2 isomers of one of the tested derivatives (HM-PAO). The brain uptake of the favoured dl-isomer of HM-PAO reaches its maximum of 4.3% (whole brain/whole body) 1 min p.i. and a clearance of less than 8% was observed 23 min p.i.

Carbon-11-labeled amino acids have been successfully used to image brain tumors by PET. This study was undertaken to evaluate the potential of L-3-[123I]-iodo-alpha-methyl tyrosine (123IMT) for metabolic imaging of brain tumors. Ten patients (glioblastoma, oligodendroglioma, lymphoma, and metastases) had early and delayed brain SPECT with a rotating gamma camera after i.v.-injection of 200-300 MBq 123IMT. In nine patients the tumors showed intense uptake of the radiotracer. Tumor-to-brain tissue ratios were between 1.4 and 2.6. 123IMT shows potentials for monitoring the effects of brain tumor therapy.

Eleven patients with Alzheimer type dementia were investigated by single-photon-emission computed tomography (SPECT) using 99mTc-hexamethylpropylene-aminoxim (HM-PAO). Nine had a typical, symmetrically reduced enrichment in the parieto-temporo-occipital area. In three of these nine patients a similar pattern was recorded additionally in the frontal, in the remaining two in the temporal or parietal region. In a semi-quantitative evaluation radioactivity concentrations in the cerebrum and cerebellum were compared. It demonstrated that there was in relation to the cerebellum a reduced concentration in seven of the eight studied cerebral regions. The relative blood flow of the parieto-temporo-occipital region was most markedly affected and in patients with Alzheimer type dementia was reduced by 25% below that of normal subjects. The results indicate that cerebral SPECT with HM-PAO is a reasonable method of investigation to confirm the diagnosis of "Alzheimer type dementia" and exclude other cerebral disease, especially if pathognomonic findings are to be obtained.

To examine the capacity of detecting regional cerebral blood flow (rCBF) disturbances in stroke, measurements with 133Xe inhalation and 123I-amphetamine (IMP) SPECT were performed within 1–2 days in 19 patients. IMP SPECT images in transverse sections consisting of outer and inner areas were correlated with 32 regions of 133Xe rCBF. 133Xe rCBF was assessed by ISI, CBF15, and F1. Inter hemispheric ratio correlation showed outer IMP uptake correlated better with 133Xe CBF indices than the inner one. With higher ratios of 133Xe rCBF, IMP uptake ratios were variable, suggesting less usefulness of this parameter in evaluation of mild ischemia. Values of IMP in outer regional hypo and hyperemic areas correlated better with those of 133Xe rCBF than the inner ones. In regional ratios of hypo and hyperemic areas from hemispheric mean, outer IMP uptake correlated with 133Xe CBF indices, reflecting regional disturbances of fast clearing tissue perfusion. Regression lines between ratios in 133Xe CBF and IMP uptake were located below one to one correlation, and dissociated more for hyperemic regions. IMP SPECT correlated better with 133Xe rCBF for tissues with reduced perfusion but underestimated hyperemic regions as measured with the 133Xe method. The data suggest outer cerebral IMP uptake evaluated by SPECT could reflect flow disturbances in the brain cortex.

In 31 patients with completed stroke (n = 30) or PRIND (n = 1) a brain SPECT with 123I-labeled amphetamines was performed. In 14 (= 45%) of the respective patients--suffering from long-lasting hemiplegia--crossed cerebellar diaschisis was present. The interval between onset of the disease and time of examination varied between 1 week and 7 years. On the other hand, patients without crossed cerebellar diaschisis did not, with one exception, suffer from hemiplegia. It is likely that this phenomenon is caused by the reduction of spino-cerebellar stimuli due to the paresis of the respective extremities.

New developments in radiopharmacology of 123I-labeled metabolic tracers and single-photon emission computerized tomography (SPECT) allow now-a-days the assessment of parameters of cardiac energy metabolism in well-defined areas of the heart muscle. This article will present a brief outline of the basic pathophysiological principles used in the application of 123I-labeled phenyl fatty acids for the evaluation of CAD. First clinical results suggest an important application of cardiac fatty acid metabolic imaging to the detection, localisation and conceivable quantitation of myocardial ischemia, myocardial infarction and assessment of tissue viability. In addition to the diagnostic applications in CAD, cardiac fatty acid metabolic imaging may provide new perspectives to pathophysiological investigations of the coupling of local flow and substrate utilisation in vivo and the effect of therapeutic interventions.

In nine patients with suspected psychogenic seizures and in three patients with proven epileptic seizures HMPAO-SPECT was performed prior to and during seizure. In the patients with later on-proven psychogenic seizures no, or only slight, changes of regional cerebral blood flow were found. Patients with proven epilepsy revealed partly normal findings interictally but during seizure a markedly increased circumscript blood flow was found in all patients. Even though PET is superior to SPECT with respect to spatial resolution, in the diagnosis of seizures HMPAO-SPECT has the advantage of enabling injection of the tracer during the seizure and the performance of the SPECT study subsequently.