Posterior bulge sign for parathyroid adenoma on Tc-99m MIBI SPECT.
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Adenoma↗
Biomedical subjects
James M Mountz
Publications and source records attributed to James M Mountz.
Indium-111 pentetreotide imaging of carcinoid tumor of the thymus.
INTRODUCTION: Carcinoid tumors are relatively rare and can occur in the thorax, abdomen, or pelvis. Indium-111 pentetreotide scanning is useful for the identification of these tumors. In this report, we present imaging findings and discussion pertaining to a 43-year-old man who presented with Cushing's syndrome resulting from a thymic carcinoid tumor. The imaging is of interest because there is not only marked uptake of In-111 pentetreotide in the thymic carcinoid tumor, but also within the adrenal glands attributable to elevated tumor-derived ACTH. METHOD: Planar and single-photon emission computed tomography (SPECT) images of the chest and abdomen were obtained 15 minutes after the injection of 6.6 mCi of In-111 pentetreotide. Further planar and SPECT images were obtained approximately 4 and 24 hours after injection of the radiopharmaceutical. Correlation of In-111 pentetreotide SPECT was made with laboratory results and CT evaluation of the chest and abdomen. RESULTS: Initial clinical workup for Cushing's syndrome included a contrast-enhanced brain magnetic resonance image that showed a small pituitary lesion thought to represent a microadenoma. Normal inferior petrosal venous sinus sampling for ACTH suggested there was an ectopic ACTH source. Subsequent CT of the chest identified a 3 x 3-cm enhancing mediastinal mass. Avid uptake within the mass on In-111 pentetreotide images suggested that the underlying cause of Cushing's syndrome was ACTH production from a thymic carcinoid. Increased uptake of In-111 pentetreotide was also noted within hyperplastic adrenal glands. Surgical resection and histologic evaluation established the diagnosis of a moderately differentiated thymic carcinoid tumor. CONCLUSION: This case illustrates the complementary ability of In-111 pentetreotide planar and SPECT imaging and CT to diagnose an ACTH-producing thymic carcinoid tumor leading to adrenal hyperplasia and Cushing's syndrome.
Adult↗
Positron emission tomography in patients with fibromyalgia syndrome and healthy controls.
OBJECTIVE: Abnormal brain findings have previously been described in fibromyalgia syndrome (FMS) by single-photon-emission computed tomography. Our goal was to investigate change in regional cerebral glucose metabolism in people with FMS by positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG). METHODS: Twelve patients with FMS and no comorbid psychiatric diagnosis and 7 healthy pain-free controls were studied with FDG-PET in a blinded manner. Those with a psychiatric diagnosis were excluded. Brain scans were obtained using a PET scanner. Semiquantitative analysis of regional 18F-FDG uptake was performed in both cortical and subcortical brain structures. RESULTS: In the resting state, there were no significant differences in 18F-FDG uptake between patients and controls for all brain structures measured. CONCLUSION: FDG-PET scan findings in FMS were not significantly different from healthy controls. Normal results in our study may be explained by discordance between regional cerebral blood flow and regional cerebral glucose metabolism.
Adult↗
Ictal SPECT analysis in epilepsy: subtraction and statistical parametric mapping techniques.
Seizures are associated with an increase in regional cerebral blood flow (rCBF). In partial seizures the increased blood flow closely corresponds with the site of seizure origin. Using tracers that accumulate and remain "fixed" in different areas of the brain proportional to rCBF at the time of injection, ictal SPECT is now an important tool for localization of seizures in a presurgical evaluation. However, the best methods for interpretation of partial seizure-induced changes in rCBF remain unclear. Numerous computer-aided tools have been used to increase objectivity and accuracy of ictal SPECT analysis. This review examines the uses of ictal-interictal subtraction methods and statistical parametric mapping (SPM) to enhance interpretation and utility of ictal SPECT. The review covers the evolution of advanced ictal SPECT imaging analysis techniques and the authors' clinical experience with the use of subtraction and SPM methods. The authors discuss the impact of ictal SPECT subtraction or difference imaging methods and the initial evidence for proof-of-principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with temporal and extratemporal lobe epilepsy. The limitations of both methodologies are discussed, and suggestions for further study of validation, improvement, and routine clinical implementation of advanced analysis methods are provided.
Algorithms↗
The accuracy of integrated PET-CT compared with dedicated PET alone for the staging of patients with nonsmall cell lung cancer.
BACKGROUND: The treatment of patients with nonsmall cell lung cancer (NSCLC) is determined by the stage. We evaluated the accuracy of staging using integrated positron emission tomography (PET) and computed tomography (CT) and compared it with dedicated PET visually correlated with CT scan. METHODS: A prospective blinded trial was performed on a consecutive series of patients with NSCLC. Patients underwent integrated PET-CT scanning with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG-18). A radiologist assigned the T, N and M status. No sooner than 2 weeks the same radiologist read the dedicated PET alone, without the integrated CT images and a T, N and M status was assigned again. The most recent CT scan was available and visually correlated with both studies. All patients underwent biopsies of suspicious N2 or N3 lymph node or distant metastases and if negative, pulmonary resection with lymphadenectomy was performed. RESULTS: There were 129 patients. Integrated PET-CT is a better predictor than PET for all stages of cancer and achieved statistical significance for stage I (52% versus 33%, p = 0.03) and for stage II (70% versus 36%, p = 0.04). It also is a better overall predictor for T status (70% versus 47%, p = 0.001) and the N status (78% versus 56%, p = 0.008). Nodal analysis shows that integrated PET-CT was more accurate for the total N2 nodes (96% versus 93%, p = 0.01) and for the total N1 nodes (90% versus 80%, p = 0.001). It was also more sensitive, specific, and had a higher positive predictive value for both N2 and N1 nodes (p < 0.05 for all). Integrated PET-CT is significantly more sensitive at the 4R, 5, 7, 10 L and 11 stations and more accurate at the 7 and 11 lymph nodes stations than dedicated PET. CONCLUSIONS: Integrated PET-CT using FDG-18 better predicts stage I and II disease as well as the T and N status of patients with NSCLC when compared with dedicated PET alone. It is more accurate at some nodal stations but still only achieves an accuracy of 96% and 90% for the N2 and N1 nodes, respectively.
Adult↗
Ictal single-photon emission computed tomography imaging in extra temporal lobe epilepsy using statistical parametric mapping.
PURPOSE: To examine the application of statistical parametric mapping (SPM) to analyze ictal single-photon emission computed tomography (SPECT) scans in surgical candidates with extratemporal lobe epilepsy. METHODS: The authors selected patients who underwent successful ictal SPECT acquisition in the process of surgical treatment of intractable partial epilepsy. Thirteen patients were identified who met inclusion criteria for confident seizure localization from either intracranial electroencephalogram recordings or epilepsy surgery outcome. In these cases, ictal scans were registered to an in-house-developed normal SPECT atlas composed of 14 spatially normalized brains of normal subjects. SPM96 was used to test on a voxel-by-voxel basis for statistically significant increases in blood flow associated with each patient's ictal scan. The results were then mapped back onto the patient's magnetic resonance image (MRI) for final interpretation. Statistical parametric mapping (SPM) analysis of ictal SPECT scans was compared to both conventional visual interpretation and the analysis of subtraction ictal SPECT co-registered to MRI (SISCOM). RESULTS: Ten of 13 patient scans showed localizing focal ictal increases in regional cerebral blood flow, all of which were concordant with ultimate epilepsy localization. Of the 3 cases not localized with SPM, 1 was localized by conventional visual interpretation and another, not localized by visual interpretation, was correctly localized with SISCOM. Two cases not localized by SISCOM were localized by both visual and SPM analysis. CONCLUSIONS: This work provides supportive evidence for proof of principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with extratemporal lobe epilepsy.
Adolescent↗
Functional assessment of pulmonary vein stenosis using radionuclide ventilation/perfusion imaging.
Pulmonary vein (PV) stenosis following catheter ablation of atrial fibrillation (AF) is a new clinical syndrome. The optimal method of assessing this syndrome is not known. We evaluated radionuclide perfusion imaging, anatomic imaging, and direct measurements of PV-left atrial (LA) pressure gradients in patients suspected of having PV stenosis after catheter ablation for the treatment of AF. The study included 11 consecutive patients who were referred to a tertiary referral center for the evaluation of symptoms suggesting or imaging evidence of PV stenosis following catheter ablation for AF. All patients underwent anatomic imaging of their PVs with direct pulmonary venography or CT scanning as well as radionuclide perfusion imaging. PV stenosis (> 50% diameter) was diagnosed by venography in 6 of the 11 patients and in 16 of 44 PVs. All six patients with PV stenosis had perfusion defects in the affected pulmonary lobe. In contrast, all of the patients without anatomic evidence of PV stenosis had normal perfusion. There were 14 PVs with stenoses of > 80% of the luminal diameter, all of which had a corresponding perfusion abnormality ascertained by perfusion scanning. In all 14 PVs with a resting PV-LA gradient of > 5 mm Hg, there was a corresponding perfusion defect. PV stenosis results in decreased perfusion in the affected lobe when the resting PV-LA pressure gradient is at least 5 mm Hg or when there is 80% luminal stenosis. A perfusion scan may serve as an effective screening tool for PV stenosis and may be most useful in assessing the hemodynamic significance of an anatomic PV stenosis.
Adult↗
The role of FDG-PET scan in staging patients with nonsmall cell carcinoma.
BACKGROUND: To assess the role of flourodeoxyglucose-positron-emission tomography (FDG-PET) scan in staging patients with nonsmall cell lung cancer (NSCLC). METHODS: We prospectively studied 400 patients with NSCLC. Each patient underwent a computed tomography (CT) scan of the chest and upper abdomen, other conventional staging studies and had a FDG-PET scan within 1 month before surgery. All suspicious N2 lymph nodes by either chest CT or by FDG-PET scan were biopsied. Patients that were N2 and M1 negative underwent pulmonary resection and complete thoracic lymphadenectomy. RESULTS: The FDG-PET had a higher sensitivity (71% vs 43%, p < 0.001), positive predictive value (44% vs 31%, p < 0.001), negative predictive value (91% vs 84%, p = 0.006), and accuracy (76% vs 68%, p = 0.037) than CT scan for N2 lymph nodes. Similarly, FDG-PET had a higher sensitivity (67% vs 41%, p < 0.001), but lower specificity (78% vs 88%, p = 0.009) than CT scan for N1 lymph nodes. FDG-PET led to unnecessary mediastinoscopy in 38 patients. FDG-PET was most commonly falsely negative in the subcarinal (#7) station and the aortopulmonary window lymph node (#5, #6) stations. It accurately upstaged 28 patients (7%) with unsuspected metastasis and it accurately downstaged 23 patients (6%). CONCLUSIONS: The FDG-PET scan allows for improved patient selection. It more accurately stages the mediastinum, however there are many false positives lymph nodes and it may be more likely to miss N2 disease in the #5, #6, and #7 stations. A positive FDG-PET scan means a tissue biopsy is indicated in that location.
Adult↗
The predictive value of creatine phosphokinase and alkaline phosphatase in identification of heterotopic ossification in patients after spinal cord injury.
OBJECTIVE: To determine the predictive value of serum levels of creatine phosphokinase (CPK) and alkaline phosphatase (ALP) in identifying patients with spinal cord injury (SCI) who are at risk to develop heterotopic ossification (HO) at the hips. DESIGN: Prospective cohort study. SETTING: Tertiary-care level I trauma center. PARTICIPANTS: Consecutive sample of 18 adults with acute traumatic SCI. Patients were excluded if they had medical or surgical conditions that are known to cause elevated enzyme levels. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Conventional hip radiographs were taken approximately 3 weeks after injury and again from between 3 to 6 months after injury. Serum ALP and CPK were measured approximately 3 weeks after SCI. Patients were later separated into 2 groups: group 1 was comprised of those who developed HO and group 2 was comprised of those who did not. RESULTS: The initial radiographs showed no evidence of HO in either group. The radiographs taken at 3 to 6 months showed HO in 7 of 18 patients. The levels of CPK at the initial evaluation were significantly higher (R=.947, P<.0024) in group 1 than in group 2 and correlated with the severity of HO. There was no correlation between serum ALP levels and subsequent development of HO between the 2 groups (P=.07). CONCLUSION: Elevated serum levels of CPK have value in predicting the HO.
Adult↗
Neuroimaging in cerebrovascular disorders: measurement of cerebral physiology after stroke and assessment of stroke recovery.
Nuclear medicine imaging can play an important role in the diagnosis of stroke risk, the differential diagnosis of vascular and parenchymal cerebral abnormalities, and the understanding and management of poststroke recovery. Radionuclide brain-imaging methods can assess hemodynamic, vascular, and metabolic status before and after stroke. Several techniques, including vasodilatory stress imaging with regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT), oxygen extraction methods with positron emission tomography (PET), and spectroscopic imaging with magnetic resonance spectroscopic imaging, offer ways to distinguish vascular from parenchymal dysfunction and to determine whether any observed abnormalities in cerebral blood flow are primary or secondary disease manifestations. The value of radionuclide imaging in assessing the efficacy of several interventional surgical procedures is presented. Data from several imaging modalities bearing on the controversial issue of luxury perfusion and reperfusion injury are analyzed, including some of the discrepancies between animal and human clinical data. Imaging evidence for white matter disease and microangiopathy is analyzed, including a quantitative rCBF pattern analysis that distinguishes between typical Alzheimer's disease and microangiopathy by using multivariate analysis of variance curve profile analysis, which shows results of significant differences in the circumferential cortical blood flow profiles at P =.01. Microangiopathy showed rCBF reduction in the frontal and frontotemporal regions as compared with the more typical reduction in posterior temporal-parietal rCBF diminution characteristic of Alzheimer's disease. Several functional neuroimaging approaches to the study of cerebral poststroke reorganization are analyzed in the context of 2 major models of recovery: the resolution of diaschisis and reorganization in spared brain. Research on these issues is presented with SPECT, PET, magnetic resonance imaging, and magnetic resonance spectroscopy. Data show how standard structural magnetic resonance imaging, (99m)Tc hexamethylpropylene amine oxime SPECT, PET imaging, and magnetic resonance spectroscopy can be used to identify the extent of permanent damage versus penumbral and remote effects of a stroke. The results of the analysis of the pure-diaschisis model show a high correlation between the rCBF brain SPECT defect volume in the cortex and the magnetic resonance spectroscopic imaging (MRSI) change in the white matter. There is a statistically significant positive correlation between the 2 (P <.01; r(2) = 0.94). The increased creatine/N-acetyl aspartate and reduced rCBF are proposed to be due to an increase in the white matter creatine component due to diaschisis and the repair mechanisms associated with increased astrocytosis, in addition to a reduction of N-acetyl aspartate in diaschitic white matter. Xenon-133 dynamic SPECT is shown to be a quantitative and sensitive measure of cerebrovascular status and hemodynamic constraints in both spared and affected brain, providing evidence for reorganization and cerebral plasticity. Fluorine-18 PET and (31)P spectroscopic imaging data show reorganizational changes in the contralesional hemisphere after stroke. The phosphocreatine-adenosine triphosphate ratio in the contralesional hemisphere was 38% +/- 17% higher than in the ipsilateral hemisphere. The phosphocreatine-adenosine triphosphate ratio was highly correlated (r = 0.88, P <.05) with increasing (18)F-fluorodeoxyglucose uptake. These results showed that there is a parallel change in glucose metabolism and high-energy phosphate metabolism associated with poststroke recovery that is proposed to be due to cerebral reorganization in the contralateral premotor cortex. The value of these results on rehabilitation strategy, including possible criteria for the use of facilitatory versus compensatory approaches, is analyzed.
Aged↗
F-18 FDG brain positron emission tomography and Tl-201 early and delayed SPECT in distinguishing atypical cerebral tumor from cerebral infarction.
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Aged↗
Molecular imaging: new applications for biochemistry.
Molecular imaging can reveal in vivo analysis and quantification of biochemical reactions. To enable cell-surface imaging of receptors, novel ligands have been developed which can be radiolabeled or imaged by bioluminescence. Specific examples include somatostatin receptors, estrogen and progesterone receptors, receptors involved in adhesion and externalization of phosphatidyl serine as an indicator of apoptosis. Central nervous system imaging can be carried out using ligands for receptors including dopamine, serotonin and Gamma amino butyric acid (GABA). In addition, tumor and metabolic imaging can be carried out with the Na-K ATPase pump using the tracer thallium-201 for SPECT or F-18 FDG for PET imaging. Finally, novel receptors or endogenous metabolic pathways can be analyzed combining cell-gene therapy to create specific tracer targets in cells that can be studied by molecular imaging. The challenge of molecular imaging is to first identify key pathways that are unique for a specific disease processes, such as atherosclerosis, cancer, CNS disorders, immunologic and arthritis disorders and next to devise a high-affinity specific small molecular ligand that can be adapted to be a radiolabeled tracer to study this pathway. Advances in genomics and proteomics combine with new peptide-chemistry approaches should provide a large number of targets and tracers in the near future to achieve these imaging objectives.
Animals↗
Granulocyte colony-stimulating factor: confounding F-18 FDG uptake in outpatient positron emission tomographic facilities for patients receiving ongoing treatment of lymphoma.
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Adult↗
Regional cerebral blood flow and magnetic resonance spectroscopic imaging findings in diaschisis from stroke.
BACKGROUND AND PURPOSE: This study evaluated blood flow and metabolite changes in cerebral diaschisis from internal capsule region infarction using regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT) and 1H magnetic resonance spectroscopic imaging (MRSI). We hypothesized that complementary measures of diaschisis effects in white matter (characterized by 1H MRSI) and gray matter (characterized by changes in rCBF) can be measured and exhibit parallel changes. METHODS: Five stroke patients and 16 normal controls underwent Tc-99m hexamethylpropyleneamine-oxime brain SPECT and 1H MRSI at 4.1 T. The metabolites N-acetyl aspartate (NAA) and creatine (Cr) were measured using 1H MRSI. The tissue content was expressed as the percent of gray or white matter in each MRSI voxel to allow comparison of the differential effects of diaschisis in gray and white matter tissue types. The blood flow and metabolite changes were evaluated at superior cerebral regions distant from the stroke to allow a measure of diaschisis relatively unconfounded by their expected changes in the infarction region. RESULTS: The rCBF SPECT data in stroke patients showed a perfusion defect, with size ranging from 1.23 cc to 10.23 cc, in the region of cortical diaschisis. 1H MRSI showed increased Cr/NAA ratios in regions of white matter diaschisis. There was a tendency for larger rCBF defect size to be associated with greater increases in Cr/NAA values in the same diaschitic cerebral hemisphere, ipsilateral to the infarction. CONCLUSION: Diaschisis ipsilateral to stroke in white matter can be characterized by 1H MRSI, and diaschisis ipsilateral to stroke in cortical gray matter regions can be characterized by changes in rCBF. The tendency for greater reductions in cortical rCBF values to be associated with increased Cr/NAA values in the same diaschitic cerebral hemisphere implies that a relationship exists between rCBF reductions in gray matter and abnormal changes in white matter subservient to it.
Adult↗
A case of spinal cord injury-related pain with baseline rCBF brain SPECT imaging and beneficial response to gabapentin.
Central pain following spinal cord injury is poorly understood, and is often resistant to conventional pain therapy regimens. We describe an individual with paraplegia who for many years experienced rapidly fluctuating, severe, unilateral pain below the level of his lesion. Prior to the initiation of pharmacological treatment, regional cerebral blood flow (rCBF) was measured during PAIN and NON-PAIN states using single photon emission computed tomography (SPECT). When experiencing pain, the subject had increased anterior cingulate gyrus blood flow, increased thalamic blood flow bilaterally and increased somatosensory cortex blood flow contralaterally but decreased caudate blood flow bilaterally. The subject's subsequent clinical course included a trial of gabapentin which produced a substantial reduction in frequency and average intensity of his episodic pain and which has been maintained for almost 2 years. This case demonstrates the correspondence between rCBF and pain associated with spinal cord injury and also suggests the potential utility of gabapentin for treatment of this central pain state.
Acetates↗
Differentiation of benign vs. malignant mass in a postirradiation cerebral arteriovenous malformation by 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography.
This report demonstrates the findings on two 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography (FDG-PET) brain scans of a 16-year-old girl with previous radiation therapy for an arteriovenous malformation (AVM) that was transformed by radiation therapy to a mass in a deep and relatively inaccessible cerebral location. Clinical neurologic examination, brain CT without and with contrast, 1.5 T MRI of the brain without and with contrast, magnetic resonance angiography (MRA), (1)H magnetic resonance spectroscopic imaging (MRSI) of the brain, and two FDG brain PET scans were performed to characterize the lesion. Magnetic resonance imaging (MRI) and (1)H MR spectroscopic findings showed a mass and surrounding vasogenic edema in the deep left parietal lobe suggestive of malignant angiosarcoma. However, an FDG-PET scan of the brain identified a large area of hypometabolism involving the left parietal lobe. The PET findings were unchanged compared to a FDG-PET scan performed one year prior, suggesting that the lesion was benign. In addition, an MRI performed six months after the second PET scan was also consistent with a benign lesion, and was unchanged from the MRI performed two years prior. We present the first detailed imaging characteristics of a mass of high clinical suspicion for malignancy resulting from transformation of an arteriovenous malformation after radiosurgery treatment. Two FDG-PET scans performed for a one-year time interval provided a noninvasive method to establish that the lesion had nonmalignant characteristics.
Adolescent↗