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Semi-quantitative method for the assessment of focal lesions in parathyroid scintigraphy with relation to histopathology: a prospective study.
Listewnik, MH, Piwowarska-Bilska, H, Kurantowicz, M, Ostrowski, M, Borowiecki, A, Safranow, K, Jasiakiewicz, K, Iwanowski, J, Chosia, M, Laszczyńska, M, et al
Nuclear medicine review. Central & Eastern Europe. 2017;(1):18-24
Abstract
BBACKGROUND The aim of this paper was to analyse our own semi-quantitative method of assessing focal lesions localised in pre-operative diagnostic scintigraphy of primary hyperparathyroidism (PHPT) using 99mTc-MIBI with washout and comparing these data with the result of the histopathological examination (HP). MATERIAL AND METHODS A total of 40 (37 female, 3 male, average age 58.7 years) patients with a suspicion of PHPT were enrolled for prospective analysis. Dual phase planar and SPECT/CT examination with 99mTc-MIBI were performed. The tumour to background ratios in the 10th and 120th minute were calculated (TBR10 and TBR120) on the basis of the planar acquisition. PTH, ionised calcium and phosphate levels were measured. Parathyroid surgery alone or combined with subtotal/total thyreoidectomy was conducted in 23 (57.5%) and 17 (42.5%) patients, respectively. A HP was performed in all patients. RESULTS Average concentration of PTH in the whole group was 243.95 pg/ml. There was a statistically significant correlation between medians of PTH concentration and parathyroid histopathological results (p = 0.01). A total of 45 lesions of increased uptake were found in 32 (80.0%) and 34 (85%) patients in the early phase and the delayed phase, respectively. The post-operative material contained 20 (44.5%) parathyroid adenomas, 11 (24.5%) cases of hyperplasia, 2 (4.4%) cancers, 4 (8.9%) cases of normal parathyroid tissue, 2 (4.4%) lymph nodes and 6 (13.3%) cases of thyroid gland tissue. The medians of TBR10 and TBR120 for lesions examined in the HP were respectively: 3.64 and 2.59 for adenoma; 3.08 and 2.18 for hyperplasia; 7.7 and 5.5 for parathyroid cancer, 4.89 and 3.16 for normal tissue and 5.26 and 2.95 for lymph nodes or thyroid gland tissue. A high correlation coefficient of TBR10 to TBR120 in the parathyroid adenoma and parathyroid hyperplasia groups was observed with r = 0.867 and r = 0.964, respectively. The ρr correlation coefficient of TBR10 to TBR120 for normal parathyroid was 0.4. There was a statistically significant association between the HP and TBR10 medians (p = 0.047), but not between histopathology and TBR120 medians (p = 0.840). CONCLUSIONS The washout technique in pre-operative 99mTc-MIBI scintigraphy is effective in detecting lesions of the parathyroid (cancer, adenoma, hyperplasia, normal tissue of the parathyroid). Parathyroid cancers in semi-quantitative analysis were characterised by a slightly higher TBR. However, it is impossible to differentiate lesions based on this data. Histopathology results are significantly associated with TBR and PTH.
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Assessment of Minimum 124I Activity Required in Uptake Measurements Before Radioiodine Therapy for Benign Thyroid Diseases.
Gabler, AS, Kühnel, C, Winkens, T, Freesmeyer, M
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2016;(8):1201-6
Abstract
UNLABELLED This study aimed to assess a hypothetical minimum administered activity of (124)I required to achieve comparability between pretherapeutic radioiodine uptake (RAIU) measurements by (124)I PET/CT and by (131)I RAIU probe, the clinical standard. In addition, the impact of different reconstruction algorithms on (124)I RAIU and the evaluation of pixel noise as a parameter for image quality were investigated. METHODS Different scan durations were simulated by different reconstruction intervals of 600-s list-mode PET datasets (including 15 intervals up to 600 s and 5 different reconstruction algorithms: filtered-backprojection and 4 iterative techniques) acquired 30 h after administration of 1 MBq of (124)I. The Bland-Altman method was used to compare mean (124)I RAIU levels versus mean 3-MBq (131)I RAIU levels (clinical standard). The data of 37 patients with benign thyroid diseases were assessed. The impact of different reconstruction lengths on pixel noise was investigated for all 5 of the (124)I PET reconstruction algorithms. A hypothetical minimum activity was sought by means of a proportion equation, considering that the length of a reconstruction interval equates to a hypothetical activity. RESULTS Mean (124)I RAIU and (131)I RAIU already showed high levels of agreement for reconstruction intervals of as short as 10 s, corresponding to a hypothetical minimum activity of 0.017 MBq of (124)I. The iterative algorithms proved generally superior to the filtered-backprojection algorithm. (124)I RAIU showed a trend toward higher levels than (131)I RAIU if the influence of retrosternal tissue was not considered, which was proven to be the cause of a slight overestimation by (124)I RAIU measurement. A hypothetical minimum activity of 0.5 MBq of (124)I obtained with iterative reconstruction appeared sufficient both visually and with regard to pixel noise. CONCLUSION This study confirms the potential of (124)I RAIU measurement as an alternative method for (131)I RAIU measurement in benign thyroid disease and suggests that reducing the administered activity is an option. CT information is particularly important in cases of retrosternal expansion. The results are relevant because (124)I PET/CT allows additional diagnostic means, that is, the possibility of performing fusion imaging with ultrasound. (124)I PET/CT might be an alternative, especially when hybrid (123)I SPECT/CT is not available.
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The short-term effect of atorvastatin on carotid plaque morphology assessed by computer-assisted gray-scale densitometry: a pilot study.
Della-Morte, D, Moussa, I, Elkind, MS, Sacco, RL, Rundek, T
Neurological research. 2011;(9):991-4
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Abstract
Soft, lipid-containing carotid plaques, which appear echolucent on ultrasound imaging, have been associated with increased risk of ischemic stroke. We sought to investigate the effect of short-term treatment with atorvastatin on the change of carotid plaque echodensity. We treated 40 stroke-free and statin-naive subjects with 80 mg atorvastatin daily for 30 days. Computer assisted gray-scale densitometry (GSD) index was calculated at baseline and 30 days after treatment from the normalized plaque images. A multiple logistic regression was used to assess the effect modification of low-density lipoprotein (LDL) cholesterol on plaque stabilization after adjusting for age, sex, and smoking. The average number of carotid plaques at baseline was 2 (range: 0-5; 27 subjects with carotid plaque) and did not change 30 days following atorvastatin treatment. The mean GSD index significantly increased from 73±16 (range: 1-125) at baseline to 89±15 (range: 1-137) at 30 days after treatment (P<0.05). The adjusted odds ratio for the positive GSD plaque index change (vs. no change or decreased gray-scale median (GSM) index) was 1.71 (95% confidence interval: 1.1-7.6, P<0.01). In conclusion, we observed decreased echolucency (increased echodensity) of carotid artery plaques after short-term treatment with atorvastatin.
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Amide proton transfer imaging of human brain tumors at 3T.
Jones, CK, Schlosser, MJ, van Zijl, PC, Pomper, MG, Golay, X, Zhou, J
Magnetic resonance in medicine. 2006;(3):585-92
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Abstract
Amide proton transfer (APT) imaging is a technique in which the nuclear magnetization of water-exchangeable amide protons of endogenous mobile proteins and peptides in tissue is saturated, resulting in a signal intensity decrease of the free water. In this work, the first human APT data were acquired from 10 patients with brain tumors on a 3T whole-body clinical scanner and compared with T1- (T1w) and T2-weighted (T2w), fluid-attenuated inversion recovery (FLAIR), and diffusion images (fractional anisotropy (FA) and apparent diffusion coefficient (ADC)). The APT-weighted images provided good contrast between tumor and edema. The effect of APT was enhanced by an approximate 4% change in the water signal intensity in tumor regions compared to edema and normal-appearing white matter (NAWM). These preliminary data from patients with brain tumors show that the APT is a unique contrast that can provide complementary information to standard clinical MRI measures.
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Carotid ultrasound phenotypes in vulnerable populations.
Riccio, SA, House, AA, Spence, JD, Fenster, A, Parraga, G
Cardiovascular ultrasound. 2006;:44
Abstract
BACKGROUND Biomarkers of carotid atherosclerosis range from those that are widely available and relatively simple to measure such as serum cholesterol levels, and B-mode Ultrasound measurement of intima media thickness (IMT) to those that are more complex and technologically demanding but perhaps potentially more sensitive and specific to disease such as total plaque volume and total plaque area measured from 3-dimensional ultrasound images. In this study we measured and compared intima media thickness (IMT), total plaque volume (TPV) and total plaque area (TPA) in two separate populations, both vulnerable to carotid atherosclerosis. METHODS In total, 88 subjects (mean age 72.8) with carotid stenosis of at least 60%, based on a peak Doppler flow, and 82 subjects (mean age 60.9) with diabetic nephropathy were assessed in a cross-sectional study. Conventional atherosclerotic risk factors were examined and the associations and correlations between these and carotid ultrasound phenotypes measured from B-mode and 3-dimensional ultrasound images were assessed. RESULTS IMT and TPV were only modestly correlated in the two separate populations (r = .6, p < .01). ANOVA analyses indicated that both IMT and TPV were significantly associated with age (p < .001) and Framingham score (p < .05), but only TPV was associated with diabetes (p < .001) and presence of plaque ulcerations (p < .01) CONCLUSION IMT and TPV were modestly correlated in a diabetic patient population and only TPV was associated with diabetes and the presence of plaque ulcerations in a diabetic population and carotid stenosis group. The 3-dimensional information provided by TPV can be critically important in unmasking association with risk factors not observed with less complex single-dimension assessments of carotid atherosclerosis such as those provided by IMT.
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PET imaging of serotonin transporters with [11C]DASB: test-retest reproducibility using a multilinear reference tissue parametric imaging method.
Kim, JS, Ichise, M, Sangare, J, Innis, RB
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2006;(2):208-14
Abstract
UNLABELLED Parametric imaging of serotonin transporters (SERT) with 11C-labeled 3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)benzonitrile ([11C]DASB) PET is a useful data analysis tool. The purpose of this study was to evaluate the reproducibility of measurements of SERT binding potential (BP) and relative blood flow (R1) by a 2-parameter multilinear reference tissue parametric imaging method (MRTM2) for human [11C]DASB studies. METHODS Eight healthy subjects (3 men, 5 women; age, 26 +/- 9 y) underwent 2 [11C]DASB PET scans separated by 1 h on the same day (dose, 703 +/- 111 MBq). Parametric images of BP and R1 were generated by MRTM2 using the cerebellum as a reference region. The k'2 (clearance rate constant from the reference region) required by MRTM2 was estimated by the 3-parameter MRTM. Reproducibility of BP and R1 measurements was evaluated by calculating bias (100 x (retest - test/test), variability (SD of the bias), and reliability (intraclass correlation coefficient = rho) for several representative regions of interest (ROIs). BP and R1 were estimated for ROI time-activity curves fitted by MRTM2 and were compared with those based on the parametric images. RESULTS The test-retest (0.066 +/- 0.013/0.06 +/- 0.011 min(-1)) MRTM k'2 reproducibility was excellent with small bias (3%) and variability (6%) and high reliability (0.95). Retest BP values were consistently lower than those of test BP values in all regions (a mean negative bias of approximately 6%; P < 0.001). The test-retest BP variability was relatively small, ranging from 4% to 13%, with rho ranging from 0.44 to 0.85. In contrast to BP, test-retest R1 values were similar with negligible bias of < or =0.1%. The test-retest R1 variability was excellent and smaller than that of BP ranging from 3% to 6%, with rho ranging from 0.58 to 0.95. BP and R1 values estimated by the ROI time-activity curve-fitting method were slightly lower ( approximately 3% and approximately 1%, respectively) than those by the parametric imaging method (P < 0.001). However, the test-retest bias and variability of BP and R1 were very similar for both ROI and parametric methods. CONCLUSION Our results suggest that [11C]DASB parametric imaging of BP and R1 with the noninvasive MRTM2 method is reproducible and reliable for PET studies of SERT.
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Two-dimensional, J-resolved spectroscopic imaging of GABA at 4 Tesla in the human brain.
Jensen, JE, Frederick, BD, Wang, L, Brown, J, Renshaw, PF
Magnetic resonance in medicine. 2005;(4):783-8
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A method for measuring brain gamma-amino butyric acid (GABA) levels is presented that combines 2D J-resolved magnetic resonance spectroscopy (J-MRS) techniques with chemical-shift imaging (2D-JMRSI) at 4 Tesla (T). The results of phantom and in vivo experiments agree well in demonstrating that the (2)CH(2) GABA resonance situated at 2.97 ppm can be resolved from the neighboring creatine (Cr) resonance at 3.03 ppm and quantified. Single-voxel, J-resolved standard and metabolite-nulled in vivo experiments on six healthy subjects reveal a broad component from the underlying macromolecules (MM) that resonates at and around 3.00 ppm, which is estimated to contribute approximately 15% to the J-resolved GABA resonance in this large voxel at a repetition time (TR) of 4.5 s. With our 2D-JMSRI at 1.25 s TR, the macromolecule resonance contribution to our GABA measurements is approximated to be 12%. Six healthy human subjects underwent scanning at 4T with this sequence, yielding a global brain GABA concentration of 0.76 +/- 0.20 mM after correction for 12% macromolecule contribution.
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Tomographic evaluation of [131I] 6beta-iodomethyl-norcholesterol standardised uptake trend in clinically silent monolateral and bilateral adrenocortical incidentalomas.
Imperiale, A, Olianti, C, Mannelli, M, La Cava, G, Pupi, A
The quarterly journal of nuclear medicine and molecular imaging : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of.... 2005;(3):287-96
Abstract
AIM: The aim of this study was three-fold: 1) to quantify [131I]-6beta-iodomethyl-norcholesterol ([131I]-NP-59) adrenal uptake trend in patients with incidentalomas, 2) to identify a specific uptake trend (TREND) capable of characterising pre-clinical Cushing syndrome (PC-CS) patients, 3) to assess the clinical availability of TREND as a prognostic factor of late clinical outcome in a cohort of patients with bilateral adrenal adenomas. METHODS Fifty-seven consecutive patients were examined using three-head SPECT at 24, 48, 72 hours following intravenous injection of [131I ]-NP-59. On the basis of the absence or presence of hormonal abnormalities, the selected population was classified as GR1 or GR2, respectively. Adrenal glands were classified into 4 groups taking into account both the patient group (GR1, GR2) and the presence (+) or absence (-) of the adenoma (AD) on CT scan. Using ROI technique, adrenal-liver uptake ratio (A/L) was estimated bilaterally at 24, 48 and 72 hours. For each adrenal group, mean [131I]-NP-59 uptake trends were derived. RESULTS TREND was significantly different between GR1/AD+ and GR2/AD+. Among GR2/AD+ patients, TREND correctly identified PC-CS with a global accuracy of 74%. Two patients with bilateral incidentaloma developed an overt CS. In both patients, TREND correctly identified the hyperfunctioning adrenal, thus permitting an effective sparing adrenalectomy. CONCLUSIONS TREND seems to be a parameter which closely reflects adrenal physiological behaviour, especially in the case of bilateral adrenal involving. The possibility to quantify even contralateral adrenal uptake as standardised index provides additional useful information about normal adrenal parenchyma and, indirectly, about adenoma functional autonomy.
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Is there a change in water proton density associated with functional magnetic resonance imaging?
Jochimsen, TH, Norris, DG, Möller, HE
Magnetic resonance in medicine. 2005;(2):470-3
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In a recent series of studies (see, for example, Stroman et al. Magn Reson Imag 2001; 19:827-831), an increase of water proton density has been suggested to correlate with neuronal activity. Owing to the significant implications of such a mechanism for other functional experiments, the functional signal changes in humans at very short echo times were re-examined by spin-echo EPI at 3 T. The results do not confirm the previous hypothesis of a significant increase in extravascular proton density at TE = 0. Instead, an alternative explanation of the effect is offered: The use of a low threshold to identify activated voxels may generate an artificial offset in functional contrast due to the inclusion of false-positives in the analysis.
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Combined PET and microdialysis for in vivo assessment of intracellular drug pharmacokinetics in humans.
Langer, O, Karch, R, Müller, U, Dobrozemsky, G, Abrahim, A, Zeitlinger, M, Lackner, E, Joukhadar, C, Dudczak, R, Kletter, K, et al
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2005;(11):1835-41
Abstract
UNLABELLED Because many drugs possess an intracellular site of action, the knowledge of intracellular concentration-time profiles is desirable. In the present study, PET, which measures total (i.e., intracellular, extracellular, and intravascular) concentrations of radiolabeled drugs in tissue, and microdialysis, which determines unbound drug concentrations in the extracellular space fluid of tissue, were combined to describe the intracellular pharmacokinetics of a model compound--that is, the (18)F-labeled antibiotic (18)F-ciprofloxacin--in vivo in humans. METHODS Ten healthy male volunteers received a mixture of 687 +/- 50 MBq of (18)F-ciprofloxacin and 200 mg of unlabeled ciprofloxacin as an intravenous bolus infusion over 10 min. The pharmacokinetics of ciprofloxacin in skeletal muscle tissue were assessed by means of combined PET and in vivo microdialysis for 5 h after drug administration. A 3-compartment pharmacokinetic model was fitted to the tissue concentration-time profiles of ciprofloxacin measured by PET to estimate the rate constants of ciprofloxacin uptake and transport. RESULTS In muscle tissue, mean total and extracellular peak concentration (C(max)) values of ciprofloxacin of 1.8 +/- 0.4 microg/mL and 0.7 +/- 0.2 microg/mL were attained at 95 +/- 34 min and 48 +/- 20 min after drug administration, respectively. The extracellular-to-intracellular exchange appeared to be very fast, with an estimated rate constant k(3) of 1.69 +/- 0.25 min(-1). An intracellular-to-extracellular concentration ratio (C(intra)/C(extra)) of 3.2 +/- 0.8 was reached at 110 min after injection and followed by sustained intracellular retention of the antibiotic for the remainder of the experiment. The predicted extracellular concentration-time profiles from the compartmental modeling were in good agreement with the measured microdialysis data. CONCLUSION The results obtained in the present study were in accordance with previous in vitro data describing cellular ciprofloxacin uptake and retention. The presently used PET/microdialysis combination might be useful during research and development of new drugs, for which knowledge of intracellular concentrations is of interest.