323,069 research outputs found
The new era of advanced placental tissue characterization using MRI texture analysis: Clinical implications
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Characterization of Hypersecreting or Non-Hypersecreting adrenal adenomas: Comparicon between Iodine-131 Nor-Cholesterol Scintigraphy and Magnetic Resonance
No full textImaging characterization of non-hypersecreting adrenal masses. Comparison between MR and radionuclide techniques.
No full textAIM: In patients with non-hypersecreting adrenal masses, tumor characterization is clinically relevant to establish the appropriate treatment planning. The aim of this study was to comparatively characterize such adrenal lesions using MR and radionuclide techniques.
METHODS:
Thirty patients with non-hypersecreting unilateral adrenal tumors underwent both MR and adrenal scintigraphy. MR was performed using SE T1- (pre- and post-gadolinium DTPA) and T2-weighted images as well as in- and out-phase chemical-shift imaging (CSI). MR qualitative and quantitative (signal intensity ratios) evaluation was performed. Radionuclide studies consisted of iodine-131 nor-cholesterol (n=20), iodine-131 MIBG (n=15) and fluorine-18 FDG PET (n=11) scans. Histology (n=16), biopsy (n=3) or clinical-imaging follow-up (n=11) demomstrated 13 adenomas, 3 cysts, 2 myelolipomas, 4 pheochromocytomas (pheos), 4 carcinomas, 1 sarcoma and 3 metastases. Comparative imaging analysis was focused on adenomas, pheos and malignant tumors.
RESULTS:
Qualitative MR evaluation showed: signal T2-hyperintensity in 46% of adenomas and in 100% of pheos and malignant tumors, no gadolinium enhancement in 92% of adenomas and definite signal intensity loss on CSI in 100% of such tumor lesions, gadolinium enhancement in 100% of pheos and in 63% of malignancies and no absolute change of signal intensity on CSI in 100% of both pheos and malignancies. Quantitative MR analysis demonstrated: significantly higher signal T2-hyperintensity of pheos compared to adenomas and malignancies as well as significantly higher enhancement after gadolinium in pheos compared to adenomas and malignancies (p<0.03). Radionuclide studies showed significantly increased nor-cholesterol uptake only in adenomas (n=13), significant MIBG accumulation only in pheos (n=4) and FDG activity only in malignant adrenal lesions (n=8).
CONCLUSION:
MR techniques may provide some presumptive criteria to characterize non-hypersecreting adrenal masses, such as no gadolinium enhancement and definite signal intensity loss on CSI in adenomas or quantitatively measured T2-hyperintensity and gadolinium enhancement in pheos. On the other hand, radionuclide modalities offer more specific findings in this setting since nor-cholesterol and MIBG scans are respectively able to reveal benign tumors such as adenoma and pheochromocytoma, while FDG imaging allows identification of malignant adrenal lesions. Adrenal scintigraphy is recommended in those patients, when MR images are uncertain or inconclusive
Rest-redistribution thallium-201 and rest technetium-99m-sestamibi SPECT in patients with stable coronary artery disease and ventricular dysfunction
No full textThe True Value of Quantitative Imaging for Adrenal Mass Characterization: Reality or Possibility?
No full text: The widespread use of cross-sectional imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), in the evaluation of abdominal disorders has significantly increased the number of incidentally detected adrenal abnormalities, particularly adrenal masses [...]
Non-Hodgkin's lymphoma in a patient with follicular thyroid cancer: the role of 99mTc-methoxy isobutyl isonitrile imaging
No full textIn the post-surgical follow-up of a patient with follicular thyroid carcinoma, a palpable mass in the left supraclavicular region was highly indicative of metastatic disease. Technetium-99m methoxy isobutyl isonitrile (99mTc-MIBI) showed an increased but heterogeneous uptake within the lesion. Surprisingly, a different neoplastic disease was histologically demonstrated. Lymph node abnormalities due to non-Hodgkin's lymphoma rather than metastatic thyroid disease were demonstrate
Impaired Left Ventricular Diastolic Filling in Patients with Acromegaly: Assessment with Radionuclide Angiography
No full textAbstract
Acromegaly is associated with increased cardiac morbidity and mortality, but it is not clear whether this is the result of a specific disease of heart muscle or of increased incidence of hypertension.
METHODS:
Twenty-six patients with acromegaly (11 male and 15 female, mean age 45 +/- 13 yr) and 15 and 12 age- and sex-matched normal controls underwent high temporal resolution radionuclide angiography and two-dimensional echocardiography at rest.
RESULTS:
Normal controls and patients with acromegaly did not differ with respect to heart rate, ejection fraction, time to end systole, peak ejection rate (PER) and time to PER. In contrast, peak filling rate (PFR), normalized to end diastolic volume (EDV), or stroke volume (SV), or expressed as the ratio of PFR-to-PER was reduced (p < 0.01), time to PFR (TPFR) was prolonged (p < 0.01), and echocardiographic left ventricular mass index was higher (p < 0.001) in patients with acromegaly compared to normals. Patients with acromegaly were divided in normotensives (group 1, n = 17) and hypertensives (group 2, n = 9). Although left ventricular mass index was significantly (p < 0.01) higher in group 2 compared to group 1, PFR and time to PFR were not different between the two groups of acromegalic patients. In the entire group of patients with acromegaly significant relationships between left ventricular mass index and EDV/s (r = -0.56, p < 0.01), SV/s (r = -0.73, p < 0.001), and PFR/PER (r = -0.61, p < 0.001) were observed.
CONCLUSION:
Patients with acromegaly have impaired left ventricular diastolic filling at rest related to greater left ventricular mass index even in the absence of systemic hypertension
Regional systolic function, myocardial blood flow and glucose uptake at rest in hypertrophic cardiomyopathy
No full textDecreased 18fluorodeoxyglucose (FDG) uptake and blood flow at rest in the ventricular septum, as compared with the lateral wall, have been reported in mildly symptomatic patients with hypertrophic cardiomyopathy (HC). To assess whether regional metabolic heterogeneity in patients with HC is related to heterogeneous regional systolic function, 10 symptomatic patients (mean age 36 +/- 17 years) with HC and no coronary artery disease underwent positron emission tomography with oxygen-15-water and FDG, and nuclear magnetic resonance imaging at rest to assess regional anatomy and systolic function. Regional absolute blood flow was similar between the ventricular septum and lateral wall. In contrast, FDG activity was significantly greater in the lateral wall than in the septum (1,023 +/- 588 vs 767 +/- 388 nCi/ml, respectively; p < 0.01). However, regional systolic wall thickening was also significantly greater in the lateral wall than in the septum (5.3 +/- 4.3 vs 2.4 +/- 4.0 mm, respectively; p < 0.001). Patients were then divided into group A (n = 5) with similar regional wall thickening in the septum and lateral wall, and group B (n = 5) with greater thickening in the lateral wall than in the septum. In both groups, regional blood flow was similar between the septum and lateral wall. However, the regional septal-to-lateral FDG activity ratio was 0.97 +/- 0.31 in group A, and 0.74 +/- 0.25 in group B (p < 0.01); the ratio in group A did not differ from that in 5 normal subjects (1.02 +/- 0.58
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