Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TOMOGRAPHY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMedDate not supplied

Improved radiologic staging of lung cancer with 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography and computed tomography registration.

PURPOSE: To determine if volumetric nonlinear registration or registration of thoracic computed tomography (CT) and 2-[18F]-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) datasets changes the detection of mediastinal and hilar nodal disease in patients undergoing staging for lung cancer and if it has any impact on radiologic lung cancer staging. METHOD: Computer-based image registration was performed on 45 clinical thoracic helical CT and FDG-PET scans of patients with lung cancer who were staged by mediastinoscopy and/or thoracotomy. Thoracic CT, FDG-PET, and registration datasets were each interpreted by 2 readers for the presence of metastatic nodal disease and were staged independently of each other. Results were compared with surgical pathologic findings. RESULTS: One hundred and thirty lymph node stations in the mediastinum and hila were evaluated each on CT, PET, and registration datasets. Sensitivity, specificity, positive predictive value, and negative predictive value, respectively, for detecting metastatic nodal disease for CT were 74%, 78%, 55%, 88%; for PET with CT side by side, 59% to 76%, 77% to 89%, 48% to 68%, and 84% to 91%; and for CT-PET registration, 71% to 76%, 89% to 96%, 70% to 86%, and 90% to 91%. Registration images were significantly more sensitive in detecting nodal disease over PET for 1 reader (P = 0.0156) and were more specific than PET (P = 0.0107 and 0.0017) in identifying the absence of mediastinal disease for both readers. Registration was significantly more accurate for staging when compared with PET for both readers (P = 0.002 and 0.035). CONCLUSION: Registration of CT and FDG-PET datasets significantly improved the specificity of detecting metastatic disease. In addition, registration improved the radiologic staging of lung cancer patients when compared with CT or FDG-PET alone.

Adult↗
PubMedDate not supplied

Preoperative image fusion of fluoro-2-deoxy-D-glucose-positron emission tomography and computed tomography data sets in oral maxillofacial carcinoma: potential clinical value.

OBJECTIVE: The aim was to evaluate the clinical and therapeutic value of digital image fusion of 2-[18]-fluoro-2-deoxy-D-glucose (F18-FDG) positron emission tomography (PET) and computed tomography (CT) in patients suffering from an oral maxillofacial carcinoma. METHODS: Seventeen patients (11 male, 6 female; age range: 45-89 years) suffering from an oral maxillofacial carcinoma underwent CT and F18-FDG-PET (333-370 MBq). The data of the 2 imaging modalities were fused on an image workstation. This image fusion was then visualized in the axial, coronal, and sagittal planes. RESULTS: PET showed a high pathologic FDG uptake in the tumor in 17 of 17 patients. CT detected the tumor in 12 of 17 patients. The image fusion of FDG-PET and CT showed the tumor in 17 of 17 patients. The final diagnosis was carcinoma of the mandible in 9 of 17 patients, carcinoma of the mouth floor in 3 of 17 patients, carcinoma of the tongue in 3 of 17 patients, carcinoma of the roof of the mouth in 1 of 17 patients, and carcinoma of the parotis gland in 1 of 17 patients. CONCLUSIONS: Preoperative image fusion of FDG-PET and CT data sets in oral maxillofacial carcinoma is possible in the clinical routine. Combined morphologic (CT) and functional (PET) imaging improves tumor localization even if the tumor is hardly visible on CT because of the artefacts of dental metallic implants (3/17 patients) or because of the small size of the tumor (2/17 patients). Image fusion is helpful for planning possible surgery (visual models) or radiotherapy (exact region of interest).

Aged↗
PubMedDate not supplied

Positron emission tomography-computed tomography imaging characteristics of an inferior vena cava tumor thrombus with magnetic resonance imaging correlation.

Thrombus of the renal vein or inferior vena cava is a known complication of renal cell carcinoma (RCC). Accurate discrimination between bland and malignant thrombus can have significant implications toward clinical management. Distinguishing between these 2 entities is not usually possible with enhanced computerized tomography (CT) or magnetic resonance imaging. This case reports the role of combined positron emission tomography-CT imaging in the accurate detection of recurrent RCC after partial nephrectomy and surgically proven tumor thrombus in the renal vein and inferior vena cava.

Carcinoma, Renal Cell↗
PubMed1996

Evaluation of hydrocephalic periventricular radiolucency by dynamic computed tomography and xenon-computed tomography.

OBJECTIVE: A common finding of computed tomography in a case of normal-pressure hydrocephalus (NPH) is periventricular radiolucency (PVL). We analyzed PVL for patients with hydrocephalus, using dynamic computed tomographic and xenon-computed tomographic techniques to differentiate NPH from similar diseases. METHODS: Dynamic computed tomography was evaluated as a method of diagnosing NPH in 14 patients with computed tomographic findings of both PVL and ventricular dilatation. Of the 14 patients, varying degrees of clinical improvement after shunt surgery were observed in 10 (shunt-effective group) but not in the remaining 4 (shunt-ineffective group). The difference in arrival time between PVL and thalamus, the difference in peak time between PVL and anterior cerebral artery, and cerebral blood flow in PVL by xenon-computed tomographic study were analyzed. RESULTS: The difference in arrival time between PVL and thalamus was significantly longer in the effective group than among the remaining patients. There was no significant difference in PVL/cerebral blood flow and the difference in peak time between PVL and the anterior cerebral artery between the two groups. CONCLUSION: Dynamic computed tomographic analysis of the difference in arrival time between PVL and thalamus is useful for diagnosing NPH and predicting response to shunting.

Aged↗
PubMed1987

Sequential computerized tomography and positron emission tomography studies in a patient with malignant glioma.

Computerized tomography (CT) and positron emission tomography (PET) using fluorine-18-deoxyglucose were performed in a patient with malignant glioma over a one-year period. Postoperatively and during radiation therapy, there was slight improvement in metabolic activity in the hemisphere ipsilateral to the tumor. After radiation therapy and during chemotherapy, there was a rapid and then gradual decline in whole brain metabolic rate by 39%. This might have been explained by radiation effect on brain. The tumor area was metabolically similar to the adjacent brain until one year after diagnosis, when an area of abnormal increased activity was noted. Even though CT scans showed minimal evidence of tumour growth, a large glioblastoma multiforme was found at autopsy at the site of the increased activity. Radiation leukoencephalopathy was also observed at autopsy. It is concluded that PET studies may offer new information regarding the metabolic effects of anti-tumor therapy, and may demonstrate regrowth of tumor prior to CT.

Brain↗
PubMed2004

Diagnostic imaging for pancreatic cancer: computed tomography, magnetic resonance imaging, and positron emission tomography.

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are sophisticated modalities typically used in the second-line diagnosis following routine clinical practice. Among them, CT is regarded as the standard imaging in diagnosing pancreatic cancer at present in Japan due to its popularity and reasonable reliability in wide-ranging diagnostic ability. However, even with multidetector row CT (MDCT), the demonstration of pancreatic cancer less than 1 cm in size remains nearly impossible. CT staging is considered accurate in one-half to two-thirds of patients, but limitations in the imaging of peripancreatic microinvasion and nodal or hepatic micrometastases still have a tendency to underestimate tumor extension. With recent advancement in imaging techniques, MRI has proven to be equal or superior to other imaging modalities in diagnosing pancreatic cancer. Most of all, it is expected that MRCP will become as effective an instrument as ultra-sonography (US) in the screening of pancreatic cancer. Functional imaging with PET using the glucose analog FDG can be used in the diagnosis of pancreatic cancer, but systemic or local disturbance of glucose metabolism may result in an incorrect diagnosis. The usefulness of PET is now considered in assessing tumor viability, monitoring tumor response to treatment, and detecting distant metastases.

Carcinoma↗
PubMed2006

Utility of positron emission tomography-computed tomography in identification of residual nodal disease after chemoradiation for advanced head and neck cancer.

OBJECTIVES: Planned neck dissection after chemoradiation (CR) is often advocated in patients with head and neck squamous cell cancer (HNSCC) with advanced nodal disease who demonstrate a clinical complete response to CR because identification of residual occult nodal disease is difficult. We sought to investigate the utility of positron emission tomography-computed tomography (PET-CT) in identifying patients with occult nodal disease after CR. STUDY DESIGN: Nonrandomized retrospective cohort analysis. MATERIALS AND METHODS: The medical records of all patients treated with primary CR for advanced HNSCC with N2 or N3 disease from December 2003 to June 2005 were reviewed. Patients with a clinical complete response were eligible for inclusion if PET-CT performed at 8 to 10 weeks after CR showed no evidence of distant disease and they were treated with a planned neck dissection. RESULTS: Seventeen patients met study criteria. PET-CT was positive for residual nodal disease in 11 (64.7%) patients, with a standardized uptake value (SUV) range of 1.7 to 3.8. Pathologic examination revealed residual viable carcinoma in five (29.4%) patients, with tumor size ranging from 2.0 to 9.5 mm. Carcinoma was present in 2 of 11 (18.2%) patients with positive PET-CT scans and 3 of 6 (50%) patients with negative PET-CT scans. The sensitivity and specificity of PET-CT in predicting occult nodal disease was 40% and 25%, respectively. There was no correlation between PET-CT findings and histologic findings (P = .26) or between SUV and size of viable tumor (P = .67). CONCLUSIONS: A significant proportion of HNSCC patients with advanced neck disease harbor residual occult metastases after CR. PET-CT is not sufficiently specific or sensitive to reliably predict the need for posttreatment neck dissection.

Adult↗
PubMedDate not supplied

Malignant pleural mesothelioma with heterologous osteoblastic elements: computed tomography, magnetic resonance, and positron emission tomography imaging characteristics of a rare tumor.

The imaging findings of a rare mixed type of malignant mesothelioma of the pleura with heterologous bone stroma in a patient without a previous history of asbestos exposure are reported. Imaging findings of this type of bone-forming pleural mesothelioma are scarcely reported in the literature, with only a few case reports describing findings on conventional radiography, computed tomography, and magnetic resonance imaging. To the best of our knowledge, no positron emission tomography imaging characteristics of this type of mesothelioma have been previously reported.

Contrast Media↗
PubMed2005

Differentiation between malignant and benign pleural effusion in patients with extra-pleural primary malignancies: assessment with positron emission tomography-computed tomography.

OBJECTIVES: We sought to define an accurate diagnostic approach for differentiating benign from malignant pleural effusion on positron emission tomography-computed tomography (PET-CT). MATERIAL AND METHODS: PET-CT studies of 31 patients with primary extrapleural malignancy and pleural effusion were reviewed retrospectively. CT parameters assessed were size and density (Hounsfield units, or HU) of the effusion and density (HU) and morphology of any solid pleural abnormality. Interpretation of PET data included review of the attenuation-corrected and nonattenuation-corrected images. RESULTS: PET-CT parameters that were found to be significant in identifying malignant pleural effusion included focal increased uptake of 18-fluorodeoxyglucose in the pleura (P<0.0001) and the presence of solid pleural abnormalities on CT (P<0.002): the sensitivity was 86% and 71%, respectively, and the specificity was 90% for each of the 2 parameters. A PET-CT pattern composed of pleural uptake and increased effusion activity on nonattenuation-corrected images was associated with sensitivity of 95%, specificity of 80%, positive predictive value of 91%, negative predictive value of 89%, and accuracy of 90%. CONCLUSIONS: On PET-CT, the presence of concomitant pleural abnormalities is the most accurate criterion in determining the malignant nature of pleural effusion.

Adult↗
PubMed2005

High-resolution whole-body magnetic resonance image tumor staging with the use of parallel imaging versus dual-modality positron emission tomography-computed tomography: experience on a 32-channel system.

OBJECTIVE: The objective of this study was to compare the accuracy in staging of various malignant tumors with whole-body magnetic resonance imaging (WB-MRI) using parallel imaging (PAT) and positron emission tomography-computed tomography (PET-CT). MATERIALS AND METHODS: In a prospective study, 41 patients withoncologic diseases underwent [F]-fluoro-2-deoxy-D-glucose PET-CT for tumor staging and WB-MRI on a 32-channel-scanner with the use of PAT. Coronal T1w and STIR sequences at 5 body levels, axial HASTE imaging of the lung, and contrast-enhanced T1w sequences of the liver, brain, and abdomen were performed. TNM stage was assessed for both modalities in a separate consensus reading using histologic results and radiologic follow up within 6 months as the standard of reference. RESULTS: Three primary and 4 recurrent tumors were detected; one recurrent tumor was missed with WB-MRI. Sixty benign and 60 malignant lymph nodes were detected with a sensitivity of 98% and specificity of 83% for PET-CT and 80%/75% for WB-MRI, respectively. One hundred ninety-one malignant and 77 benign distant lesions were detected with a sensitivity/specificity of 82% for PET-CT and 96%/82% for WB-MRI. Accuracy for correct TNM staging was 96% for PET-CT and 91% for WB-MRI. CONCLUSION: WB-MRI and PET-CT are reliable imaging modalities for tumor staging. WB-MRI is highly sensitive in detecting distant metastases; PET-CT is superior in lymph node staging. PAT makes high-resolution WB-MRI feasible within less than 1 hour.

Adult↗
PubMedDate not supplied

Whole-body positron emission tomography and positron emission tomography/computed tomography in gynecologic oncology.

The advent of positron emission tomography (PET) and PET/computed tomography (CT) now enables us to detect metabolically active gynecologic cancers with greater accuracy than was possible with anatomic imagings. Fluorine-18 fluorodeoxyglucose PET has been useful in differentiation of malignant from benign lymph nodes, and residual or recurrent cancers from post-treatment changes. PET/CT produces additional information for the diagnosis and tissue biopsy as well as radiotherapy planning. This paper reviews the principle and clinical utility of PET and PET/CT in the diagnosis, staging, recurrence, therapeutic response as well as prognosis of gynecologic cancers.

Female↗
PubMed2000

Ratio-images calculated from interictal positron emission tomography and single-photon emission computed tomography for quantification of the uncoupling of brain metabolism and perfusion in epilepsy.

PURPOSE: Image processing techniques were applied to interictal positron emission tomography (PET) and single-photon emission computed tomography (SPECT) brain images to aid in the localization of epileptogenic foci by calculating a functional image that represents the degree of coupling between perfusion and metabolism. Uncoupling of these two functions has been demonstrated to be a characteristic of epileptogenic tissue in temporal lobe epilepsy and has the potential to serve as a diagnostic measure for localization in other areas as well. METHODS: Interictal PET ((18)F-FDG) and interictal SPECT ((99m)Tc-HMPAO) scans were acquired from 11 epilepsy patients. The metabolism and perfusion images were three-dimensionally spatially registered, and a functional ratio-image was computed. These functional maps are overlaid onto a three-dimensional rendering of the same patient's magnetic resonance imaging anatomy. RESULTS: In all patients, an average uniform perfusion-to-metabolism ratio showed approximately constant values throughout most of the whole brain. However, the epileptogenic area (confirmed on surgery) demonstrated an area of elevated perfusion/metabolism in the grey matter. CONCLUSIONS: Although hypometabolism in the PET image was observed in most of these patients, the calculation of a functional ratio-image demonstrated localized foci that in some cases could not be observed on the PET image alone. The ratio-image also yields a quantitative measure of the uncoupling phenomenon.

Adolescent↗
PubMedDate not supplied

Ictal and interictal activity in partial epilepsy recorded with multichannel magnetoelectroencephalography: correlation of electroencephalography/electrocorticography, magnetic resonance imaging, single photon emission computed tomography, and positron emission tomography findings.

Ictal and interictal epileptic activity was recorded for the first time by multichannel magnetoencephalography (MEG) in three patients with partial epilepsy. Pre- and intra-operative localization of the epileptogenic region was compared. The interictal epileptic activity was localized at the same region of the temporal or frontal lobe as the ictal activity. Main zones of ictal activity were shown to evolve from the tissue at the centers of interictal activity. Pre- and intra-operative electrocorticography (ECoG) as well as postoperative outcome confirmed localization in the temporal and frontal lobe. Results also correlated with findings from scalp EEG, interictal and ictal single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance imaging (MRI). Combined multichannel MEG/EEG recording permitted dipole localization of interictal and ictal activity.

Adult↗
PubMed1991

Physostigmine in Alzheimer's disease: effects on cognitive functioning, cerebral glucose metabolism analyzed by positron emission tomography and cerebral blood flow analyzed by single photon emission tomography.

The effect of acute, intravenous administration of physostigmine on measures of brain activity and cognitive functioning were investigated in 14 patients with Alzheimer's disease. Regional cerebral glucose metabolism was assessed using (18F)-fluoro-2-deoxy-D-glucose and positron emission tomography, and cerebral blood flow was assessed using 123I-iodoamphetamine single photon emission tomography. Although physostigmine enhanced cerebral blood flow in most patients, only one patient showed significant clinical improvement. This patient, however, also showed a very pronounced improvement in cerebral glucose metabolism. It is concluded that these preliminary findings hold considerable promise for our appreciation of the pathophysiology of dementing illness as well as our understanding of centrally acting compounds of interest in Alzheimer's disease.

Aged↗
PubMed2005

Positron emission tomography scanning is not superior to whole body multidetector helical computed tomography in the preoperative staging of colorectal cancer.

BACKGROUND: The role of positron emission tomography with the glucose analogue [18F] fluoro-2-deoxy-D-glucose (FDG-PET) in the initial staging of disease in patients with primary colorectal cancer (CRC) has not been adequately assessed. AIMS: To evaluate the additional value of FDG-PET as a staging modality, complementary to routine multidetector row computed tomography (MDCT) in patients with CRC. METHODS: Forty four patients with CRC underwent preoperative MDCT and FDG-PET. The accuracy of intraoperative macroscopic staging was also investigated compared with histopathological diagnosis. All FDG-PET images were evaluated with respect to detectability of the primary tumour, lymph node involvement, and distant metastases. Both MDCT and FDG-PET diagnoses and treatment plan were compared with surgical and histopathological results. RESULTS: Thirty seven patients underwent surgery. Tumour detection rate was 95% (42/44) for MDCT, 100% (44/44) for FDG-PET, and 100% (37/37) for intraoperative macroscopic diagnosis. Pathological diagnosis of T factor was T1 in five, T2 in four, T3 in 24, and T4 in four cases. Concordance rate with pathological findings of T factor was 57% (21/37) for MDCT and 62% (23/37) for macroscopic diagnosis. Lymph node involvement was pathologically positive in 19 cases. Regarding N factor, overall accuracy was 62% (23/37) for MDCT, 59% (22/37) for FDG-PET, and 70% (26/37) for macroscopic diagnosis. For all 44 patients, FDG-PET findings resulted in treatment changes in only one (2%) patient. CONCLUSION: FDG-PET is not superior to routine MDCT in the initial staging of primary CRC.

Adult↗
PubMed1982

N-isopropyl(I-123)p-iodoamphetamine brain scans with single-photon emission tomography: discordance with transmission computed tomography.

Transmission computed tomography (CT) brain scans were compared with N-isopropyl (I-123)-p-iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) brain scans to determine if there was a correlation between morphology, as seen on CT, and cerebral perfusion changes detected by IMP SPECT. In 12 patients with acute stroke, four showed no discordance between the edema seen on CT and perfusion deficits seen on IMP SPECT; five had positive IMP scans while initial CT scans were negative and follow-up CT scans demonstrated edema in the region of perfusion deficit seen on the IMP scans; and in four patients, the average perfusion deficit was 2.3 times greater than the edema shown on CT at 2 cm above the canthal-meatal line. In nine control patients, there was a 2.3% difference in IMP activity between the right and left hemispheres. The 12 stroke patients showed 30.3% less IMP activity in the abnormal hemisphere compared with the normal side. Three patients, one with temporal lobe seizure, one with hemiballismus, and the third with idiopathic intention tumor, had 54% greater IMP activity on the side of movement or seizure than on the normal side. The discordance between IMP and CT scans was clearly demonstrated in cases in which CT showed no abnormality but IMP provided information on function, reflected in increased or decreased cerebral perfusion.

Amphetamines↗