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At least 19 recordsLinked to original sources
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed1981

Intensified tomography: enhancement of soft-tissue discrimination in conventional tomography of the brain. A comparison with computed tomography.

A new technique to enhance the conventional tomographic images of soft tissues such as the brain is described. The method, called intensified tomography, optimizes the information available from conventional tomography through the use of three modifications: a specially designed filter to attenuate selectively the x-ray beam at the source to compensate for the variable shape of the skull, an improved blurring movement to reduce system artifacts, and enhanced image contrast by the superimposition of several identical images on the same film or television screen. Intensified tomography was performed in 200 patients. Ten of these tomographic images later were compared with computed tomographic (CT) scans to confirm that the ventricles could be imaged with intensified tomography. An unexpected case of lenticulocapsular calcification was also demonstrated by intensified tomography and confirmed by CT. It is proposed that intensified tomography be developed as a preliminary screening technique to be used in places where CT is not readily available.

Brain↗
PubMed1992

Absorbed doses and energy imparted from tomography for dental implant installation. Spiral tomography using the Scanora technique compared with hypocycloidal tomography.

Tomography is sometimes needed to obtain information on the amount of bone available in the maxilla and in the posterior parts of the mandible prior to implant surgery. Both conventional and computed tomography can be employed. Recently a new imaging device, the Scanora, has been introduced which can be used for spiral tomography. The aim of this study was to compare absorbed doses and energy imparted from this new unit with those from conventional hypocycloidal tomography using the Philips Universal Polytome. A multi-film cassette with five pairs of calcium tungstate screens was used in the latter while a single film technique was used with the Scanora. The absorbed dose measurements were made on an anthropomorphic phantom. Most absorbed doses were found to be below 0.2 mGy except those to the major salivary glands. The absorbed doses with the Scanora were higher than with the Polytome. The beam direction and shorter focus-object distance in the Scanora influenced the absorbed dose distribution. The energy imparted was found to be low for both techniques, 1.8-1.9 mJ with the Scanora for both jaws, and for hypocycloidal tomography 0.78 mJ in the maxilla and 1.3 mJ in the mandible.

Absorption↗
PubMed2001

Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy.

BACKGROUND: The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG). METHODS: Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients. RESULTS: Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs. CONCLUSIONS: Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.

Adolescent↗
PubMed2002

Detection of recurrent or persistent nasopharyngeal carcinomas after radiotherapy with technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography: comparison with 18-fluoro-2-deoxyglucose positron emission tomography.

BACKGROUND: The diagnostic accuracy of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) and computed tomography (CT) of the head and neck for differentiating recurrent or residual nasopharyngeal carcinomas (NPC) from benign lesions after radiotherapy was compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG). METHODS: Thirty six NPC patients underwent head and neck CT, Tc-MIBI SPECT, and FDG-PET four months after radiotherapy to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations of nasopharyngeal biopsies were performed for all 36 patients. No patients had multiple foci of NPC. RESULTS: Based on biopsy results, the sensitivity, specificity, and accuracy of CT for differentiating recurrent or residual NPC from benign lesions were 73%, 88%, and 83%, respectively. The sensitivity, specificity, and accuracy of Tc-MIBI SPECT were 73%, 96%, and 89%, respectively. The sensitivity, specificity, and accuracy of FDG-PET were 100%, 96%, and 97%, respectively. Combination CT and Tc-MIBI SPECT for 28 NPC patients with congruent results showed the same sensitivity, specificity, and accuracy of 100%, 96%, and 96%, respectively, as FDG-PET for differentiating recurrent or residual NPC from benign lesions. In eight patients with incongruent results between CT and Tc-MIBI SPECT, FDG-PET correctly differentiated two benign lesions and six recurrent or residual NPCs. CONCLUSIONS: In detecting recurrent or residual NPC, FDG-PET is the best tool. However, combined use of CT and Tc-MIBI SPECT can result in the same accuracy as FDG-PET.

Adolescent↗
PubMedDate not supplied

Differentiating recurrent or residual nasopharyngeal carcinomas from post-radiotherapy changes with 18-fluoro-2-deoxyglucose positron emission tomography and thallium-201 single photon emission computed tomography in patients with indeterminate computed tomography findings.

The aim of this study was to compare the accuracy of 18-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and thallium-201 (Tl-201) single photon emission computed tomography (SPECT) in differentiating recurrent/residual nasopharyngeal carcinomas (NPC) from post-radiotherapy (RT) changes in patients with indeterminate computed tomography (CT) findings. Twenty NPC patients with indeterminate CT findings were included at least 4 months after RT. CT, FDG-PET, Tl-201 SPECT and biopsy were performed within 1 week. The final diagnoses were based on biopsy findings and clinical follow-up for at least 6 months. For differentiating recurrent/residual NPC from post-RT changes in patients with indeterminate CT findings, the sensitivity, specificity and accuracy of FDG-PET were 100.0%, 92.3% and 96.0%, respectively. The sensitivity, specificity and accuracy of Tl-201 SPECT were 91.7%, 92.3% and 92.0%, respectively. Based on this study's findings, we can conclude FDG-PET is more sensitive but equally specific as Tl-201 SPECT is differentiating recurrent/residual NPC from post-RT changes in patients with indeterminate CT findings.

Adolescent↗
PubMed2000

Positron emission tomography in lymphoma: comparison with computed tomography and Gallium-67 single photon emission computed tomography.

With the advent of positron emission tomography (PET), metabolic imaging has become a reality for tumor staging and monitoring response to therapy in lymphoma. Increased Fluorine-18 fluorodeoxyglucose ([(18)F]FDG) uptake in lymphomas has been well documented in the literature; it is based upon elevated glycolysis and longer residence time of FDG in malignant cells compared to most normal tissues. This suggests that in tumor staging, FDG-PET may be more sensitive and specific than the anatomic imaging modalities. Computed tomography (CT) is the standard imaging modality for the staging and restaging of lymphoma, and Gallium-67 ((67)Ga) scintigraphy has played an important role in monitoring response to therapy and follow-up of patients. Published results suggest that FDG-PET is superior to (67)Ga imaging and may be equal or superior to CT for the detection of nodal as well as extranodal involvement in lymphoma.

Aged↗
PubMed2003

Effect of oral contrast agents on computed tomography-based positron emission tomography attenuation correction in dual-modality positron emission tomography/computed tomography imaging.

RATIONALE AND OBJECTIVES: To evaluate the effect of iodine- and barium-based contrast agents on the computed tomography (CT)-based positron emission tomography (PET) attenuation correction in dual-modality PET/CT. METHODS: Experiments were conducted on a Society of Nuclear Medicine/National Electrical Manufacturers Association-PET phantom equipped with cylinders containing [18F]-2-fluoro-2-desoxy-D-glucose. The main compartment was filled with iodine (0.5-10%), barium (0.5-50%), or water (negative control). The error in attenuation correction was determined by comparison of measured tracer quantities in the presence of contrast agents with expected quantities. Contrast agent attenuation was demonstrated to be comparable to in vivo conditions. RESULTS: The presence of contrast agents resulted in an overestimation of the intracylindrical activity concentration on PET images and overestimation directly related to contrast concentrations (iodine 5-38%; barium 15-580%). Iodine and barium concentrations in clinical use resulted in an activity overestimation of 20 +/- 1.8% for iodine and 21 +/- 2.9% for barium. CONCLUSION: An overestimation of the tracer activity concentration is to be expected in the presence of oral contrast agents, if PET attenuation correction is attained CT-based.

Administration, Oral↗
PubMed1993

Anti-CEA immunoscintigraphy might be more useful than computed tomography in the preoperative thoracic evaluation of lung cancer. A comparison between planar immunoscintigraphy, single photon emission computed tomography (SPECT), and computed tomography.

While a clinical, plain radiographic, and bronchoscopic assessment yields most of the essential information needed in lung cancer, computed tomography (CT) of the thorax provides diagnostic information previously unobtainable, potentially capable of reducing the number of explorative thoracotomies. In a few recent studies, immunoscintigraphy with anti-carcinoembryonic antigen (anti-CEA) monoclonal antibodies (MA) has shown remarkable staging potential. To compare the diagnostic accuracy of the two techniques, we photoscanned with indium-111 (111In)-labeled-F(ab')2 fragments of the murine anti-CEA MA FO23C5 45 patients, who were pathologically assessed for possible loco-regional extension of lung cancer. Both planar and single photo emission computed tomography (SPECT) images were obtained. Additionally, CT of the thorax (contiguous CT slices, 10 mm thick, from the lung apices to the upper abdomen), and other routine tests of preoperative evaluation were obtained. On the basis of 37 (N1, T3, and T4), 38 (N2), and 12 (N3) pathologically documented sites, an accuracy of 65, 76, 92, 78, and 86 percent (SPECT images), and 62, 68, 42, 78, and 84 percent (CT images) was calculated (figures are relevant to N1, N2, N3, T3, and T4 disease, respectively). Thus, both techniques shared a significant margin of error in almost all the categories of evaluation; however, immunoscintigraphy showed equivalent, and, in the lymph node assessment, superior results to CT. A marginal improvement of diagnostic accuracy was recorded combining the three techniques in one case (SPECT plus planar immunoscintigraphic images), while there was no benefit in any possible integration of CT and immunoscintigraphic images. In patients with peripheral nonsquamous cell cancers, the accuracy of anti-CEA immunoscintigraphy was of 90 percent or higher. Variations in the modality of performing immunoscintigraphy, such as changes in the dose of antibody fragments to be injected, in the percentage of radiolabeling, or in the time of imaging, affected the quality of immunoscintigraphic series, and the consequent interpretation of findings. At the present time, there are very few reliable tests capable of selecting patients to proceed directly to thoracotomy or to receive some intermediate surgical test, such as a prior mediastinoscopy. Traditionally, CT has been this type of "filter-test." If current findings will be confirmed in future studies, anti-CEA immunoscintigraphy might replace CT in the evaluation of particular subgroups of patients, such as patients with peripheral nonsquamous cell bronchogenic carcinoma.

Adult↗
PubMed1988

[Conventional tomography, computerized tomography and proton spin tomography in lung disorders].

In addition to conventional tomography, CT and MRI have been introduced into clinical pulmonary radiology in recent years. Involving little or no ionizing radiation, these two digital imaging methods offer well-defined sections that can be post-processed to analyze different anatomical compartments. MRI of the lung currently faces technical problems, in particular motion artifacts and low proton density, and is more expensive. Thus, it is still reserved for selected problems, e.g. lesion characterization or vascular pathology. CT has replaced conventional tomography for many indications. The performance of these imaging methods in clinical problem situations, such as obstruction of the central bronchial tree, solitary pulmonary nodules, metastases, larger focal lesions, or diffuse disease, is discussed. A rational approach to percutaneous lung biopsy is suggested.

Biopsy↗
PubMedDate not supplied

[Changes in the brain of persons who participated in the cleaning-up of the Chernobyl AES accident based on the data of radiodiagnosis (single-photon emission-computed radionuclide tomography, x-ray computed tomography and magnetic resonance tomography)].

Presents the data of x-ray examinations of the brain in cleaner-ups of the consequences of the Chernobyl power plant accident who complained of headaches, ache in the bones, poor memory, giddiness, weakness, a drastic drop of performance ability, fits with loss of consciousness. Hypometabolic foci localized both in the white and gray matter of the brain were revealed. X-Ray computer-aided tomography and magnetic imaging showed dilatation of the ventricular system of the brain, dilatation of the subarachnoidal spaces, symmetrical reduction of the density of medullary tissue round the bodies and anterior and posterior horns of lateral ventricles, round the third ventricle, near semi-oval centers, as well as solitary or multiple focal reduction of medullary tissue density. Findings of x-ray methods of diagnosis permit a conclusion on a complex organic involvement of the brain in subjects who participated in liquidation of the consequences of the Chernobyl power plant accident. The most typical are signs of the hypertensive hydrocephalic syndrome with cerebrospinal fluid disturbances and of the vascular encephalic syndrome with development of focal postischemic malacia of the brain matter.

Adult↗
PubMedDate not supplied

Detection of hepatocellular carcinoma: comparison of dynamic three-phase computed tomography images and four-phase computed tomography images using multidetector row helical computed tomography.

PURPOSE: The purpose of our study was to assess the value of additional early arterial phase computed tomography (CT) imaging in the detection of hepatocellular carcinoma (HCC) by comparing three-phase and four-phase imaging by using multidetector row helical CT. METHODS: Twenty-five patients with 33 HCCs underwent four-phase helical CT imaging. The diagnosis was established by pathologic examination after surgical resection in 19 patients and by biopsy in six. Four-phase CT imaging comprises early arterial, late arterial, portal venous, and delayed phase imaging obtained 25 seconds, 45 seconds, 75 seconds, and 180 seconds after the start of contrast material injection using multidetector row helical CT. Three-phase CT images (late arterial, portal venous, and delayed phase) and four-phase CT images (early arterial, late arterial, portal venous, and delayed phase) were interpreted independently for the detection of HCC by three blinded observers on a segment-by-segment basis. Sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (Az) for three-phase CT images and four-phase CT images were calculated. The enhancement pattern of HCC was analyzed on early arterial and late arterial phase imaging. RESULTS: The mean sensitivity of three- and four-phase CT images was 94% and 93%, respectively. The differences between sensitivities were not statistically significant (all p > 0.05). The mean specificities of three- and four-phase CT images were 99% and 98%, respectively. The differences between the specificities were not statistically significantly (all p > 0.05). Neither were the mean areas under the ROC curve for four-phase CT images (Az = 0.976) and three-phase CT images (Az = 0.971) statistically significant (p > 0.05). On early arterial phase imaging, 16 HCCs were hyperattenuating and 17 HCCs were isoattenuating. On late arterial phase imaging, 24 HCCs were hyperattenuating and nine HCCs were isoattenuating. CONCLUSIONS: Additional early arterial phase imaging did not improve the detection of HCC compared with three-phase CT images, including late arterial, portal venous, and delayed phase imaging.

Adult↗
PubMed2001

Correlating computed tomography and positron emission tomography scan with operative findings in metastatic colorectal cancer.

INTRODUCTION: Several studies have been performed comparing computed tomography scan with positron emission tomography scan in clinical decision making. Unfortunately, therapeutic decisions are being made based on positron emission tomography scan data without a clear understanding of how well the diagnostic findings correlate with the clinical findings. METHODS: A retrospective review of 41 patients with metastatic colorectal cancer was performed. All patients had both a computed tomography scan and a positron emission tomography scan before surgical exploration. All underwent surgical re-exploration. Findings were divided into hepatic, extrahepatic, and pelvic regions of the abdomen. Computed tomography scan and positron emission tomography scan findings were either confirmed or refuted by the operative findings. RESULTS: Positron emission tomography scan was found to be more sensitive than computed tomography scan when compared with actual operative findings in the liver (100 vs. 69 percent, P = 0.004), extrahepatic region (90 vs. 52 percent, P = 0.015), and abdomen as a whole (87 vs. 61 percent, P < 0.001). Sensitivities of positron emission tomography scan and computed tomography scan were not significantly different in the pelvic region (87 vs. 61 percent, P = 0.091). In each case, specificity was not significantly different between the two examinations. CONCLUSION: Computed tomography scan and positron emission tomography scan are both diagnostic tests useful in the evaluation of metastatic colorectal cancer. However, positron emission tomography scanning is more sensitive than computed tomography scanning and more likely to give the correct result when actual metastatic disease is present.

Abdominal Neoplasms↗
PubMed1996

Mediastinal lymph node staging of non-small-cell lung cancer: a prospective comparison of computed tomography and positron emission tomography.

We compared the abilities of positron emission tomography and computed tomography to detect N2 or N3 lymph node metastases (N2 or N3) in patients with lung cancer. Positron emission tomography detects increased rates of glucose uptake, characteristic of malignant cells. Patients with peripheral tumors smaller than 2 cm and a normal mediastinum were ineligible. All patients underwent computed tomography, positron emission tomography, and surgical staging. The American Thoracic Society lymph node map was used. Computed and positron emission tomographic scans were read by separate radiologists blinded to surgical staging results. Lymph nodes were "positive" by computed tomography if larger than 1.0 cm in short-axis diameter. Standardized uptake values were recorded from areas on positron emission tomography corresponding to those from which biopsy specimens were taken; if greater than 4.2, they were called "positive." Seventy-five lymph node stations (2.8 per patient) were analyzed in 27 patients. Computed tomography incorrectly staged the mediastinum as positive for metastases in three patients and as negative for metastases in three patients. Sensitivity and specificity of computed tomographic scans were 67% and 83%, respectively. Positron emission tomography correctly staged the mediastinum in all 27 patients. When analyzed by individual node station, there were four false positive and four false negative results by computed tomography (sensitivity = 60%, specificity = 93%, positive predictive value = 60%). Positron emission tomography mislabeled one node station as positive (100% sensitive, 98% specific, positive predictive value 91%). The differences were significant when the data were analyzed both for individual lymph node stations (p = 0.039) and for patients (p = 0.031) (McNemar test). Positron emission tomography and computed tomography are more accurate than computed tomography alone in detecting mediastinal lymph node metastases from non-small-cell lung cancer.

Adult↗
PubMed2004

[18F] 3-deoxy-3'-fluorothymidine positron emission tomography: alternative or diagnostic adjunct to 2-[18f]-fluoro-2-deoxy-D-glucose positron emission tomography in the workup of suspicious central focal lesions?

BACKGROUND: 2-[(18)F]-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography has been established as a standard diagnostic imaging method in the preoperative workup of suspicious pulmonary focal lesions, showing a sensitivity of more than 90% and a specificity of about 80%. Determination of malignant pulmonary lesions with FDG positron emission tomography depends on the assessment of glucose metabolism. However, false-positive findings can occur in inflammatory processes, such as sarcoidosis or pneumonia. The thymidine analogue 3-deoxy-3[(18)F]-fluorothymidine (FLT) is a new positron emission tomography tracer that more specifically targets proliferative activity of malignant lesions. The objective of this study was to determine whether FLT positron emission tomography, in comparison with FDG positron emission tomography, provides additional information in the preoperative workup of central pulmonary focal lesions. METHODS: In this prospective study FLT and FDG positron emission tomography examinations were performed as a part of the preoperative workup in 20 patients with histologically confirmed bronchial carcinoma, 7 patients with benign lesions, and 1 patient with an atypical carcinoid. Results were compared with final pathologic findings. RESULTS: For staging of the primary tumor, FLT positron emission tomography revealed a sensitivity of 86% and a specificity of 100% compared with a sensitivity of 95% and a specificity of 73% for FDG positron emission tomography. For N staging, the sensitivity of FLT positron emission tomography was 57% and the specificity was 100%, and for FDG positron emission tomography, the sensitivity was 86% and the specificity was 100%, respectively. CONCLUSIONS: Our preliminary findings indicate specific FLT uptake in malignant lesions. The number of false-positive findings in FDG positron emission tomography might be reduced with FLT positron emission tomography. Therefore positron emission tomography imaging with FLT represents a useful supplement to FDG in assessing the malignancy of central pulmonary focal lesions.

Adenocarcinoma↗
PubMedDate not supplied

The utility of 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography and combined positron emission tomography and computed tomography in lymphoma and melanoma.

The purpose of this article is to review the clinical utility of FDG and FDG PET/CT imaging in lymphoma and melanoma. A review of the important articles supporting the use of FDG PET imaging in the staging, restaging, and monitoring of response to therapy in lymphoma and melanoma is provided. The intent is to give the nuclear medicine physician and or radiologist the perspective of what may be important clinically to make FDG PET imaging an integral part of the workup of lymphoma and melanoma patients. Specific clinical scenarios and uptake patterns that are unique for lymphoma and melanoma are discussed to ensure relevant and proper interpretation of the FDG PET scans. FDG PET scanning in summary is a useful imaging modality in the staging, restaging, and response evaluation of patients with lymphoma and melanoma.

Brain↗