HMPAO SPECT to assess neurologic deficits during balloon test occlusion

The purpose of this study was to determine if one could objectively and preoperatively predict the safety of permanent occlusion of an internal carotid artery with 99mTc-HMPAO brain SPECT. METHODS: Twenty-four patients underwent balloon test occlusion of the internal carotid arteries because of neck and skull base tumors. We assessed the uptake of both middle cerebral artery territories before and during balloon test occlusion with 99mTc-HMPAO brain SPECT using the semiquantitative analysis. The results were compared with other factors, including neurologic examination, arterial stump pressure and electroencephalogram. RESULTS: Nineteen patients experienced no neurological deterioration or any problem during balloon test occlusion. The comparative uptake of their middle cerebral artery territories was 95%-101% of the pre-balloon test occlusion state. The remaining five patients showed severe neurologic symptoms, such as transient hemiplegia and unconsciousness. The comparative uptake of their middle cerebral artery territories was 77%-85% of the pre-balloon test occlusion state and was well matched with other factors. CONCLUSION: Technetium-99m-HMPAO brain SPECT before and during balloon test occlusion seems to be a simple and objective method for predicting permanent neurologic deficits when the comparative uptake of middle cerebral artery territories during balloon test occlusion is less than 85% of that before balloon test occlusion.ope

Increased contralateral cerebellar uptake of technetium-99m-HMPAO on ictal brain SPECT

Crossed cerebellar diaschisis (CCD) is a well-known brain SPECT finding in stroke patients. Two reports, however, have described supratentorial and contralateral cerebellar hyperperfusion (crossed cerebellar hyperperfusion) on ictal brain SPECT in epileptic patients. The purpose of this study was to assess the usefulness of crossed cerebellar hyperperfusion (CCH) for the detection of epileptic foci on ictal scan. METHODS: Twelve patients with complex partial seizures having characteristic clinical, electroencephalographic (EEG) and brain SPECT findings were included. Fifteen to 20 mCi 99mTc-HMPAO were injected intravenously during the seizure period or the aura for the ictal SPECT study. The SPECT findings were visually assessed to determine whether the finding of CCH was valuable in the localization of ictal foci. RESULTS: Epileptic foci were found in the right temporal (n = 6), left temporal (n = 4), right occipital (n = 1) and left frontal (n = 1) areas. CCH was observed in 8 (75%) of the 12 patients. In two patients, contralateral cerebellar uptake was more obvious than that in the epileptic foci. In the interictal scans, cerebellar activity, which was increased in ictal period, was equalized in seven of eight patients, while perfusion was diminished in the remaining patient. CONCLUSION: CCH is a frequent finding of ictal brain SPECT and may aid in the lateralization of epileptic foci.ope

Detection of tuberculous lymphadenopathy by positron emission tomography/computed tomography in a patient with Behçet's disease

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The Proper Use of PET/CT in Tumoring Imaging

PET using FDG has been proposed as a functional whole body imaging modality that images various types of malignancies with relatively high sensitivity and specificity in a reasonably short time. It depicts a lesion based on abnormal glucose metabolism whereas CT as a high-resolution anatomical imaging detects malignant process mostly based on altered anatomy. PET/CT combines the advantages of PET and CT, and has a great value in early detection of disease, accurate staging or restaging, early assessment of treatment response, decision on therapeutic plans, and rapid localization of recurrence. Exact anatomical localization of a lesion with increased FDG uptake by CT is considered to be the most important factor that improves the diagnostic accuracy of PET/CT. So far, limited studies have been reported using PET/CT in comparison with PET only and mainly proved additional value of PET/CT in malignant tumors in which conventional PET already had advantages over anatomical imaging. PET/CT appears to have a promising role in the field of radiotherapy planning. Another potential of PET/CT would be in the evaluation of tumors with low FDG uptake by way of CT or new PET tracers. PET/CT is in the stage of its early infancy and further studies remain to be performed to establish applications of PET/CT in clinical oncology. In this review, we will discuss the principle of PET, the background of the emergency of PET/CT, advantages, pitfalls, and debates of PET/CT along with clinical applications and future perspectives of thereof.ope

Reversible extraskeletal uptake of bone scanning in primary hyperparathyroidism

Metastatic calcification within soft tissue, such as the lung and stomach, is associated with hyperparathyroidism, chronic renal failure, hemodialysis, metastatic neoplasm and hypervitaminosis D. Bone scanning agents variably accumulate within these extraskeletal metastatic calcifications. We report a patient with primary hyperparathyroidism whose bone scan revealed abnormal uptake in the liver, lung, stomach and parathyroid gland followed by complete resolution of extraskeletal uptake less than 1 wk after parathyroidectomy.ope

Imaging of Cancer Metabolism using Positron Emission Tomography

In the 1920 s, Warburg reported an observation that cancer cells depend on glycolysis even in the presence of available oxygen likely due to impaired function of mitochondria. Since then, this Warburg s effect has been the most important hypothesis in cancer metabolism and is considered as a seventh hallmark of many human cancers. Aerobic glycolysis was originally attributable to increased bioenergetic needs in rapidly proliferating cancer cells. Recently, biosynthetic aspects of aerobic glycolysis, which reprograms cancer metabolism to synthesize macromolecules such as nucleotides, fatty acids, amino acids, etc., are under active investigation. Introduction of positron emission tomography (PET) and metabolic radiotracers including F-18 flurorodeoxyglucose (FDG) and C-11 acetate made it possible to image cancer metabolism in vivo and to renew the interests on this issue. Studies have found that cancer cells with highly glycolysis features are associated with resistance to many chemotherapeutic regimens and radiation treatment. Therefore, development of glycolytic inhibitors can have an incremental effect to conventional treatments. In addition, functional imaging with metabolic radiotracers will continuously play important roles in detecting cancers and monitoring therapeutic responses to novel anti-metabolic approaches to cancer cells.ope

Developmental Disability Animal Model Based on Neonatal Lipopolysaccharide with Altered 5-HT Function

Developmental disability shows life-long behavioral abnormality with no significant physical malformation. This study was undertaken to develop an animal model for developmental disability by using two-factor approach. Lipopolysaccharide (LPS), a bacterial toxin, and NAN-190, a 5-HT1A receptor antagonist, were administered to Sprague-Dawley rats on postnatal day (PND) 5 to induce inflammation and an altered 5-HT system, respectively. Long-term alteration of behavior occurred in the drug-treated groups. The LPS-treated group showed impaired motor coordination in the Rota-rod test. The LPS- treated or both LPS and NAN-190-treated groups showed impaired fore-paw muscle power in the wire maneuver test. These groups also showed decreased white matter volume and increased serotonergic fibers. The LPS and NAN-190-treated group also exhibited neurologic deficit in the placing reaction test and impaired equilibrium function in the tilt table test. The results showed that a variety of altered behaviors can be generated by two factor model, and suggested that combination of important etiologic factors and possible underlying defects is a promising strategy of establishing an animal model for developmental disabilities.ope

The Role of Gastric Distention in Differentiating Recurrent Tumor from Physiologic Uptake in the Remnant Stomach on 18F-FDG PET

Physiologic (18)F-FDG uptake in the stomach can often cause false-positive results and lowers the usefulness of (18)F-FDG PET in evaluating the remnant stomach. We assessed the role of gastric distension to see whether it is beneficial for the differentiation of recurrent tumors from physiologic (18)F-FDG uptake in the remnant stomach. METHODS: Thirty patients (22 men and 8 women; age range, 27-80 y; mean age, 58.3 y) with a history of subtotal gastrectomy for gastric cancer underwent (18)F-FDG PET for various clinical indications. After whole-body imaging, the patients were asked to drink water, and then spot imaging of the stomach was performed. (18)F-FDG uptake in the remnant stomach was considered positive for malignancy if it was persistently increased, whether focal or diffuse, after water ingestion. We used 2 standardized uptake value (SUV) criteria to differentiate benign from malignant uptake. First, a lesion was considered benign if its SUV was less than 2 on whole-body imaging. Second, for a lesion with an SUV of 2 or above, it was classified as benign if SUV decreased by more than 10% after water ingestion. RESULTS: Visual analysis of whole-body images produced 9 true-negative, 4 false-positive, 16 true-positive, and 1 false-negative results. Use of additional spot images produced 12 true-negative, 1 false-positive, 15 true-positive, and 2 false-negative results. When an SUV cutoff of 2 was applied for malignancy before water ingestion, all 17 patients with local recurrence were correctly identified, but 11 of the 13 patients without local recurrence were falsely considered to have a recurrent tumor in the remnant stomach. To reduce the false-positive results, we used the second SUV criterion after water ingestion. Use of that criterion produced 4 false-negative results although it correctly identified the 11 false-positive results as true negative. CONCLUSION: Gastric distension by having patients drink a glass of water seems to be a simple, cost-effective way of improving the diagnostic accuracy of (18)F-FDG PET in patients with suspected recurrence in the remnant stomach. Visual analysis with special attention to the configuration of (18)F-FDG activity after water ingestion seems to be more useful than the change in SUV in evaluating the remnant stomach.ope

Recent Advances in Radionuclide Therapy

Radionuclides are naturally occurring unstable atoms that undergo radioactive decay. There are ways of radioactive decay emitting different types of radiation based on their physical properties. Radiation for medical purposes include gamma rays, characteristic X-rays, negative and positive electrons, and alpha particles. Different from external radiotherapy, radionuclide therapy internally delivers therapeutic doses of radiation to the targeted tissue. Historically, P-32 orthophosphate was used for the management of myeloproliferative disorders. I-131 has been used for the treatment of hyperthyroidism as well as thyroid cancer for decades. It is one of the most commonly used therapeutic radionuclides in the current practice and its usefulness has been well established by selectively ablating thyroid tissue. For bone pain by osteoblastic metastases, phosphorus-32, strontium-89, samarium-153, or rhenium-186 could be effectively used in combination with narcotics. Another well known radionuclide therapy is I-131 MIBG for the palliation of patients with inoperable tumors of neural crest origin. In contrast to systemic administration of radioactive materials, local control of malignant tumors could be done by delivering radiation through an intratumoral or intraarterial route. In addition, radioactive skin patch or stent has a promising role in killing skin cancers, esophageal cancer, or malignant biliary strictures. Recently, I-131 or Y-90 conjugated with monoclonal antibodies increases the efficacy of radiation damage to lymphoma tissue employing the targeting effect of monoclonal antibodies. Likewise, radionuclide therapy in combination with gene therapy seems to be promising albeit tumor specific ways of gene delivery should be further investigated. Other possible candidates in radionuclide therapy are radioactive peptides and antisense oligonuclides.ope

Left ventricular aneurysm after myocardial infarction

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