The measurement of pathologically low levels of tissue pO2 is an important diagnostic goal for determining the prognosis of many clinically important diseases including cardiovascular insufficiency, stroke and cancer. The target tissues nowaday have mostly been tumors or the myocardium, with less attention centered on the brain. Radiolabelled nitroimidazole or derivatives may be useful in identifying the hypoxic cells in cerebrovascular disease or traumatic brain injury, and hypoxic-ischemic encephalopathy. In acute stroke, the target of therapy is the severely hypoxic but salvageable tissue. 18F-MISO PET and 99mTc-EC-metronidazole SPECT in patients with acute ischemic stroke identified hypoxic tissues and ischemic penumbra, and predicted its outcome. A study using 123I-IAZA in patient with closed head injury detected the hypoxic tissues after head injury. Up till now these radiopharmaceuticals have drawbacks due to its relatively low concentration with hypoxic tissues associated with/without low blood-brain barrier permeability and the necessity to wait a long time to achieve acceptable target to background ratios for imaging in acute ischemic stroke. It is needed to develop new hypoxic marker exhibiting more rapid localization in the hypoxic region in the brain. And then, the hypoxic brain imaging with imidazoles or non-imidazoles may be very useful in detecting the hypoxic tissues, determining therapeutic strategies and developing therapeutic drugs in several neurological disease, especially, in acute ischemic stroke.
Anoxia ; Blood-Brain Barrier ; Brain Injuries ; Brain* ; Craniocerebral Trauma ; Head Injuries, Closed ; Humans ; Hypoxia, Brain* ; Hypoxia-Ischemia, Brain ; Imidazoles ; Myocardium ; Neuroimaging ; Permeability ; Prognosis ; Radiopharmaceuticals ; Stroke ; Tomography, Emission-Computed, Single-Photon

Acute event in cerebrovascular disease is the second most common cause of death in Korea following cancer, and it can also cause serious neurologic deficits. Understanding of perfusion status is important for clinical applications in management of patients with cerebrovascular diseases, and then the attacks of ischemic neurologic symptoms and the risk of acute events can be reduced. Therefore, the normal vascular anatomy of brain, various clinical applications of acetazolamide-enhanced brain perfusion SPECT, including meaning and role of assessment of vascular reserve in carotid stenosis before procedure, in pediatric Moyamoya disease before and after operation, in prediction of development of hyperperfusion syndrome before procedure, and in prediction of vasospasm and of prognosis in subarachnoid hemorrahge were reviewed in this paper.
Acetazolamide ; Brain* ; Carotid Stenosis ; Cause of Death ; Humans ; Korea ; Moyamoya Disease ; Neurologic Manifestations ; Perfusion ; Prognosis ; Tomography, Emission-Computed, Single-Photon*

Quantitative analysis of dynamic brain PET data using a tracer kinetic modeling has played important roles in the investigation of functional and molecular basis of various brain diseases. Parametric imaging of the kinetic parameters (voxel-wise representation of the estimated parameters) has several advantages over the conventional approaches using region of interest (ROI). Therefore, several strategies have been suggested to generate the parametric images with a minimal bias and variability in the parameter estimation. In this paper, we will review the several approaches for parametric imaging with linearized methods which include graphical analysis and mulilinear regression analysis.
Bias (Epidemiology) ; Brain Diseases ; Brain* ; Linear Models

Advance of neuroimaging technique has greatly influenced recent brain research field. Among various neuroimaging modalities, positron emission tomography has played a key role in molecular neuroimaging though functional MRI has taken over its role in the cognitive neuroscience. As the analysis technique for PET data is more sophisticated, the complexity of the method is more increasing. Despite the wide usage of the neuroimaging techniques, the assumption and limitation of procedures have not often been dealt with for the clinician and researchers, which might be critical for reliability and interpretation of the results. In the current paper, steps of voxel-based statistical analysis of PET including preprocessing, intensity normalization, spatial normalization, and partial volume correction will be revisited in terms of the principles and limitations. Additionally, new image analysis techniques such as surface-based PET analysis, correlational analysis and multimodal imaging by combining PET and DTI, PET and TMS or EEG will also be discussed.
Brain ; Electroencephalography ; Electrons* ; Functional Neuroimaging* ; Magnetic Resonance Imaging ; Multimodal Imaging ; Neuroimaging ; Neurosciences ; Positron-Emission Tomography*

This review focuses on the clinical use of (18)F-FDG PET to evaluate multiple myeloma. (18)F-FDG PET is useful for diagnosis, staging of multiple myeloma and differential diagnosis of myeloma related disease such as monoclonal gammopathy of undetermined significance or plasmacytoma. For therapy response, (18)F-FDG PET may be effective after chemotherapy for multiple myeloma and radiotherapy for plasmacytoma.
Diagnosis, Differential ; Monoclonal Gammopathy of Undetermined Significance ; Multiple Myeloma ; Plasmacytoma

PURPOSE: According to the development of CT scanner in PET/CT system, the role of CT unit as a diagnostic tool has been more important. To improve the diagnostic ability of CT scanner, it is a key aspect that CT scanning has to be performed with high dose energy and intravenous (IV) contrast. So we investigated the effect of IV contrast media on the maximum SUV (maxSUV) of normal tissues and pathologic lesions using PET/CT scanner with high dose CT scanning. MATERIALS AND METHODS: The study enrolled 13 patients who required PET/CT evaluation. At first, the patients were performed whole body non-contrast CT (NCCT - 120 kVp, 130 mAs) scan. Then contrast enhanced CT (CECT) scan was performed immediately. Finally PET scan was followed. The PET emission data were reconstructed twice, once with the NCCT and again with the CECT. We measured the maxSUV of 10 different body regions that were considered as normal in all patients. Also pathologic lesions were investigated. RESULTS: There were not seen focal artifacts in PET images based on CT with IV contrast agent. Firstly, 130 normal regions in 13 patients were evaluated. The maxSUV was significantly different between two PET images (p<0.001). The maxSUV was 1.1+/-0.5 in PET images with CECT-corrected attenuation and 1.0+/-0.5 in PET images with NCCT-corrected attenuation. The limit of agreement was 0.1+/-0.3 in Bland-Altman analysis. Especially there were significant differences in 6 of 10 regions, apex and base of the right lung, ascending aorta, segment 6 and segment 8 of the liver and spleen (p<0.05). Secondly, 39 pathologic lesions were evaluated. The maxSUV was significantly different between two PET images (p<0.001). The maxSUV was 4.7+/-2.0 in PET images with CECT-corrected attenuation and 4.4+/-2.0 in PET images with NCCT-corrected attenuation. The limit of agreement was 0.4+/-0.8 in Bland-Altman analysis. CONCLUSION: Although there were increases of maxSUVs in the PET images based on CT with IV contrast agent, it was very narrow in the range of limit of agreement. So there was no significant effect to clinical interpretation for PET images that were corrected attenuation with high dose CT using IV contrast.
Aorta ; Artifacts ; Body Regions ; Contrast Media ; Fluorodeoxyglucose F18* ; Humans ; Liver ; Lung ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography* ; Spleen ; Tomography, X-Ray Computed

PURPOSE: Incidence of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) is known to be higher than that in general population. However, it is difficult to discriminate pulmonary nodule in patients with IPF, because underlying IPF can be expressed as lung nodules. We evaluated the diagnostic performance of FDG PET in discriminating lung nodule in patients with IPF. METHODS: We retrospectively reviewed 28 lung nodules in 16 subjects (age; 67.53+/-9.83, M:F=14:2). Two patients had previous history of malignant cancer (small cell lung cancer and subglottic cancer). The diagnostic criteria on chest CT were size, morphology and serial changes of size. FDG PET was visually interpreted, and maximal SUV was calculated for quantitative analysis. RESULTS: From 28 nodules, 18 nodules were interpreted as benign nodules, 10 nodules as malignant nodules by histopahthology or follow-up chest CT. The sensitivity and specificity of FDG PET were 100% and 94.4%, while those of CT were 70.0% and 44.4%, respectively. Malignant nodule was higher maxSUV than that of benign lung nodules (7.68+/-3.96 vs. 1.22+/-0.65, p<0.001). Inflammatory lesion in underlying IPF was significantly lower maxSUV than that of malignant nodules (1.80+/-0.43, p<0.001). The size of malignant and benign nodule were 23.95+/-10.15 mm and 10.83+/-5.23 mm (p<0.01). CONCLUSION: FDG PET showed superior diagnostic performance to chest CT in differentiating lung nodules in patients with underlying IPF. FDG PET could be used to evaluate suspicious malignant lung nodule detected by chest in patients with IPF.
Follow-Up Studies ; Humans ; Idiopathic Pulmonary Fibrosis* ; Incidence ; Lung ; Lung Neoplasms ; Retrospective Studies ; Sensitivity and Specificity ; Thorax ; Tomography, X-Ray Computed

PURPOSE: Diabetes mellitus (DM) is a critical disease with higher rates of cardiovascular morbidity and mortality due to myocardial ischemia and infarction. There is growing interest in how to determine high-risk patients who are candidates for screening testing. This study was performed to evaluate the incidence of coronary artery disease (CAD) in diabetic patients detected by Tc-99m MIBI myocardial perfusion SPECT (MPS) and to assess risk factors of CAD and cardiac hard events. SUBJECTS AND METHODS: 203 diabetic patients (64 male, mean age 64.1+/-9.0 years) who underwent MPS were included between Jan 2000 and July 2004. Cardiac death and nonfatal myocardial infarction (MI) were considered as hard events, and coronary angioplasty and bypass surgery >60 days after testing were considered as soft events. The mean follow-up period was 36+/-18 months. Patients underwent exercise (n=6) or adenosine stress (n=197) myocardial perfusion SPECT. RESULTS: Perfusion defects on MPS were detected in 28.6% (58/203) of the patients. There was no cardiac death but 11 hard events were observed. The annual cardiac hard event rate was 1.1%. In univariate analysis of clinical factors, typical anginal pain, peripheral vascular disease, peripheral polyneuropathy, and resting ECG abnormality were significantly associated with the ocurrence of hard events. Anginal pain, peripheral vascular disease, and resting ECG abnormality remained independent predictors of nonfatal MIs with multivariate analysis. Abnormal SPECT results were significantly associated with high prevalence of hard events but not independent predictors on uni- and multivariate analyses. CONCLUSION: Patients who were male, had longer diabetes duration (especially over 20 years), peripheral vascular disease, peripheral polyneuropathy, or resting ECG abnormality had higher incidence of CAD. Among clinical factors in diabetic patients, typical angina, peripheral vascular disease, peripheral polyneuropathy, and resting ECG abnormality were strong predictors of hard events.
Adenosine ; Angioplasty ; Coronary Artery Disease* ; Coronary Vessels* ; Death ; Diabetes Mellitus* ; Diagnosis* ; Electrocardiography ; Follow-Up Studies ; Humans ; Incidence ; Infarction ; Male ; Mass Screening ; Mortality ; Multivariate Analysis ; Myocardial Infarction ; Myocardial Ischemia ; Perfusion* ; Peripheral Vascular Diseases ; Polyneuropathies ; Prevalence ; Risk Factors* ; Tomography, Emission-Computed, Single-Photon*

PURPOSE: Although radionuclide cisternography (RNC) is an useful study to detect cerebrospinal fluid (CSF) leakage in the patient with spontaneous intracranial hypotension (SIH), it sometimes fails to demonstrate the site of CSF leakage. The aim of the study is to improve the detection of leakage site of CSF and to reduce time for the study in RNC using modified protocol (m-RNC). MATERIALS AND METHODS: The study consists of 8 studies of 7 patients (38+/-8 years, M:F=2:5) with SIH, who underwent m-RNC following administration of 185-222 MBq of 99mTc-DTPA into the lumbar subarachnoid space. Sequential images were obtained the whole spine with the head including urinary bladder at 10 minute, 30 minute, 1 hour, 2 hour, 4 hour and 6 hour. Radioactivity of extradural space and urinary bladder was evaluated. RESULTS: Leakage site of CSF was identified in all 8 cases by m-RNC. Leakage site was cervicothoracic junction (CTJ, n=3), CTJ with C1-2 (n=2), CTJ with thoracic spine, thoracolumbar spine and lumbar spine (each n=1). All cases presented leakage sites within 1 hour and multiple sites, where CTJ was included in 6 cases. Only one case presented additional site in 6 hour image. Early radioactivity within the urinary bladder was noted in 6 cases, but that was following after identification of the leakage site. CONCLUSION: Radionuclide cisternography is sensitive to detect the leakage site of CSF and is expected to improve the detection of CSF leakage site and reduce time for the study using modified protocol.
Cerebrospinal Fluid ; Head ; Humans ; Intracranial Hypotension* ; Radioactivity ; Spine ; Subarachnoid Space ; Urinary Bladder

PET detects only less than 50% of early gastric cancer and 62-98% of advanced gastric cancer. Therefore, mass screening programs are recommended for all adults over the age of 40 for early detection and early treatment of gastric cancer through endoscopy or various radiological tests. The most important step after being diagnosed with gastric cancer is accurate staging, which mainly evaluates tumor resectability to avoid unnecessary surgery. Important factors that affect tumor resectability are whether the tumor can be separated from adjacent organs or important blood vessels, the extent of lymph node metastasis, presence of peritoneal metastasis, or distant organ metastasis. To evaluate the extent of local tumor invasion, anatomical imaging that has superior spatial resolution is essential. There are a few studies on prognostic significance of FDG uptake with inconsistent results between them. In spite of lower sensitivities for lymph node staging, the specificities of CT and PET are very high, and the specificity for PET tends to be higher than that for CT. Limited data published so far show that PET seems less useful in the detection of lung and bone metastasis. In the evaluation of pleural or peritoneal metastasis, PET seems very specific but insensitive as well. When FDG uptake of the primary tumor is low, the distant metastasis is also known to show low FDG uptake reducing its detection. There are only a few data available in the evaluation of recurrence detection and treatment response using FDG PET.
Adult ; Blood Vessels ; Endoscopy ; Humans ; Lung ; Lymph Nodes ; Mass Screening ; Neoplasm Metastasis ; Positron-Emission Tomography and Computed Tomography* ; Recurrence ; Sensitivity and Specificity ; Stomach Neoplasms* ; Unnecessary Procedures