Hyperfunctional parathyroid glands with 99mTc-MIBI scan: semiquantitative analysis correlated with histologic findings.
(33/873)
The purpose of this study was to correlate the semiquantitative analysis of 99mTc-methoxyisobutyl isonitrile (MIBI) scan with histologic findings of hyperfunctional parathyroid glands. METHODS: Early and delayed cervical images of MIBI scans were reviewed in 31 patients who eventually underwent parathyroidectomies because of biochemically suspected hyperparathyroidism ([HPT], primary, n = 13; secondary, n = 18). The sensitivity of a scan for localizing the diseased glands was determined by comparing scan findings with pathologic findings, which were considered the gold standard. The average ratio of parathyroid-to-thyroid (P/T) count was compared between glands with large and small areas of whole gland, chief cell, oxyphil cell or cellular components. The mean areas of whole gland, chief cells and oxyphil cells were also compared between glands detected by MIBI scan and those that the scan missed. RESULTS: There were 99 resected lesions, including 9 parathyroid adenomas and 61 hyperplastic parathyroids. The sensitivity for localizing the diseased glands in patients with primary HPT (91%) was higher than that in patients with secondary HPT (83%). Significantly greater average P/T counts ratio on both early and delayed images was observed in the diseased glands with greater areas of whole gland, chief cells, oxyphil cells or cellular components. Fifty-nine MIBI-positive glands had significantly greater average areas of whole gland (P < 0.001) and chief cell (P = 0.002) than did 11 MIBI-negative glands. CONCLUSION: The uptake of MIBI in hyperfunctional parathyroid is dependent on gland size and the amount of cellular components, chief cells and oxyphil cells. However, the amount of oxyphil cells does not clearly affect the results of MIBI parathyroid scintigraphy, because it is small in most hyperfunctional glands. (+info)
Simultaneous assessment of myocardial free fatty acid utilization and left ventricular function using 123I-BMIPP-gated SPECT.
(34/873)
This study was designed to evaluate the methodological feasibility of 123I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP)-gated SPECT to assess regional and global left ventricular (LV) function in comparison with 99mTc-sestamibi (methoxyisobutyl isonitrile [MIBI])-gated SPECT and first-pass radionuclide angiography (FPRNA). METHODS: Forty-four patients with stable coronary artery disease underwent rest BMIPP-gated SPECT (111 MBq, 60 s/step) and rest MIBI-gated SPECT (600 MBq, 40 s/step) within a week. From both gated SPECT studies, regional defect scores (DS), wall motion scores (WMS) and wall-thickening scores (WTS) were evaluated visually using 4-point scales for nine segments, and LV ejection fraction (EF) (%) was automatically calculated using Quantitative Gated SPECT (QGS) software. FPRNA was also performed on injection of MIBI. RESULTS: Exact agreement between the two gated SPECT studies was 84.1% (kappa = 0.706, r = 0.907, P < 0.0001) in WMS and 87.1% (kappa = 0.662, r = 0.884, P < 0.0001) in WTS. LVEF obtained from BMIPP-gated SPECT linearly correlated with those from MIBI-gated SPECT (y = -0.27 + 0.944x, r = 0.948, SEE = 5.00, P < 0.0001) and FPRNA (y = -7.32 + 1.042x, r = 0.919, SEE = 6.19, P < 0.0001). Even in 21 patients with mismatch segments (BMIPP DS > MIBI DS), agreement was considered to be acceptable in WMS (81.5%, kappa = 0.707, r = 0.853, P < 0.0001) and in WTS (76.7%, kappa = 0.526, r = 0.754, P < 0.0001), and correlation in LVEF remained good between BMIPP-gated SPECT and MIBI-gated SPECT (y = -1.24 + 0.955x, r = 0.938, SEE = 6.25, P < 0.0001) or FPRNA (y = -6.03 + 1.024x, r = 0.913, SEE = 7.38, P < 0.0001). CONCLUSION: BMIPP-gated SPECT can evaluate regional and global LV function with the QGS software. Therefore, BMIPP-gated SPECT offers the opportunity for simultaneous assessment of myocardial free fatty acid utilization and LV function. (+info)
Gated myocardial perfusion tomography for the assessment of left ventricular function and volumes: comparison with echocardiography.
(35/873)
The purpose of this study was to evaluate left ventricular volumes and function by gated SPECT using different tracers and protocols in comparison with quantitative echocardiography. Gated myocardial perfusion scintigraphy permits simultaneous assessment of left ventricular perfusion, function and volumes. Information is scanty regarding the accuracy of absolute left ventricular volumes measurements by this technique. METHODS: We performed gated SPECT and echocardiography within 15 d of each other in 109 consecutive patients (53 men, 56 women; mean age 63 +/- 14 y). Gated tomographic data, including left ventricular volumes and ejection fraction, were processed using an automatic algorithm, whereas echocardiography used standard techniques. RESULTS: The correlations between gated tomography and echocardiography with respect to end-diastolic volume, end-systolic volume and left ventricular ejection fraction were good to excellent (all P < 0.001, r values > or = 0.68), regardless of the use of poststress or rest/redistribution images, 201Tl or 99mTc tracers. End-systolic volume was similar with gated tomography and echocardiography (P = ns), but end-diastolic volume and left ventricular ejection fraction were significantly higher with echocardiography (P < or = 0.05). CONCLUSION: Quantitative gated tomography, using either 201Tl or 99mTc tracers, has a good correlation with echocardiography for the assessment of left ventricular volumes and ejection fraction. These results support the clinical use of this new technique. (+info)
Forward cardiac output measurement with first-pass technique using 99mTc-labeled myocardial perfusion imaging agents.
(36/873)
The aim of this study was to develop and validate a new first-pass method for the measurement of forward cardiac output (CO) using 99mTc-labeled myocardial perfusion imaging agents. METHODS: In protocol 1, to test the new method for measuring CO, the conventional method and the new method for CO measurement were performed in 1 d in 57 patients (32 men, 25 women; age 68 +/- 11 y). In the conventional method, radionuclide angiography (1 frame/s) with in vivo 99mTc labeling (110 MBq) of red blood cells was performed for 2 min in the left anterior oblique projection. Five minutes later, a 1-min equilibrium image was obtained, and a blood sample was taken for calculation of the distribution volume. To obtain data for the new method, further radionuclide angiography (1 frame/sec) with 99mTc labeling (600-740 MBq) of red blood cells was then performed in the anterior projection. CO was calculated using the following equation: CO = Cmax x V(LV)/integral of f(t)dt, where Cmax is the background-corrected peak count of the whole thorax during angiography, integral of f(t)dt is the area under the gamma variate-fitted left ventricular (LV) time-activity curve after background correction and V(LV) is the LV volume obtained by the area length method applied to the radionuclide angiography and myocardial tomography. In protocol 2, to evaluate the new method, 24 patients (16 men, 8 women; age 71 +/- 9.2 y) underwent radionuclide angiography with 99mTc-tetrofosmin (600-740 MBq), and the measured CO was compared with the CO obtained by the conventional method with 99mTc-labeled red blood cells. RESULTS: In protocol 1, good correlation was observed between the CO by the new method (Y) and the CO by the conventional method (X): Y = 1.0X + 57 mL/min and r = 0.95. There was good agreement between the two methods (mean difference -56 +/- 381 mL/min). Inter- and intraobserver correlation coefficients were 0.96 and 0.98, respectively. In protocol 2, the CO by the new method using 99mTc-tetrofosmin (Y) showed a good correlation with the CO by the conventional method (X): Y = 0.90X + 453 mL/min and r = 0.93. Good agreement between the two methods was observed (mean difference 73 +/- 390 mL/min). Inter- and intraobserver correlation coefficients were 0.95 and 0.98, respectively. CONCLUSION: This new method permits accurate forward CO measurement using the first-pass data with 99mTc-terofosmin, which is applicable to other 99mTc-labeled myocardial perfusion imaging agents. (+info)
Changes in the left ventricular outflow tract after transcoronary ablation of septal hypertrophy (TASH) for hypertrophic obstructive cardiomyopathy as assessed by transoesophageal echocardiography and by measuring myocardial glucose utilization and perfusion.
(37/873)
AIMS AND METHODS: Transcoronary ablation of septal hypertrophy (TASH) leads to marked clinical and haemodynamic improvement in patients with hypertrophic obstructive cardiomyopathy. In order to obtain more detailed information about changes in the outflow tract after TASH, transoesophageal echocardiography and a repeat invasive investigation were conducted before as well as 2 weeks and 6 months after TASH (n=62). In a subset of patients (n=11), metabolism and perfusion of the myocardium ((18)F-FDG-PET and(99m)Tc-MIBI-SPET) were investigated. RESULTS: After TASH there was a typical regional subaortic contraction disorder. It was quantified by a significant decrease in the fractional shortening of the left ventricular end-diastolic diameter, which declined from an average of 40.6% to 18.0%. The end-diastolic diameter increased from an average of 39.1 to 40.6 mm. There was also a significant reduction in septal thickness, which continued for up to 6 months after TASH, from an average of 20.0 mm to 11.1 mm in the region of ablation and from 23. 2 to 21.7 mm outside this region. The decrease in the gradient post TASH corresponded with a concomitant significant increase in the outflow tract area from a mean value of 1.04 cm(2)before the process to a value of 3.0 cm(2)after. In contrast to coronary heart disease, these changes were accompanied by non-diffuse, well demarcated subaortic-septal necrosis verified by(18)F-FDG-PET and(99m)Tc-MIBI-SPET. On average the TASH induced necrotic area comprised 6.6% of the left ventricle and correlated significantly with echocardiographic changes in the outflow tract. CONCLUSIONS: Alterations post TASH indicated that this catheter interventional treatment for hypertrophic obstructive cardiomyopathy affects the specific region of obstruction. The changes reflect a 'therapeutic remodelling' of the outflow tract of the left ventricle. They were demonstrable over the entire 6 months investigation period and obviously constituted the basis of post TASH clinical and haemodynamic improvement. Progressive alterations post TASH (post TASH reduction of subaortic septal thickness and an increase in the end-diastolic diameter) need special consideration during long-term follow up. (+info)
Threshold values for preserved viability with a noninvasive measurement of collateral blood flow during acute myocardial infarction treated by direct coronary angioplasty.
(38/873)
BACKGROUND: Quantitative measures of myocardial perfusion defect severity from acute (99m)Tc-sestamibi tomographic images (nadir) have correlated closely with collateral and residual antegrade blood flow during acute myocardial infarction. The purpose of this study was to determine whether a viability threshold could be identified from this measure in patients with acute myocardial infarction treated in a homogeneous manner with successful reperfusion therapy. METHOD AND RESULTS: The study group consisted of 61 patients with acute myocardial infarction with a risk area of >6% LV treated with primary angioplasty between 120 and 240 minutes after symptom onset. All patients were injected with 20 to 30 mCi of (99m)Tc-sestamibi before primary angioplasty and imaged after the procedure. Acute myocardium at risk (MAR) and subsequent infarct size (IS) were quantified by a threshold program. Severity (nadir) from the acute image was the lowest ratio of minimal/maximum counts from 5 short-axis slices. Infarct location was anterior in 22 and inferior in 39 patients. MAR was 33+/-15% LV and IS was 13+/-15% LV: 23 patients had no infarction despite MAR similar to those with infarction. Receiver-operator characteristic curve analysis identified a nadir value of 0.26 as providing the best separation of patients with and without infarction (sensitivity, 74%; specificity, 74%). This nadir threshold varied by infarct location: anterior defect, 0.21; inferior defect, 0.31. The sensitivity and specificity for absent infarction for these values were anterior, 69% and 67%, and inferior, 88% and 84%, respectively. CONCLUSIONS: In a time frame in which the presence of residual blood flow is important, the severity of the acute (99m)Tc-sestamibi defect can be used to predict whether infarction will develop despite successful reperfusion. (+info)
Role of Tc-99m MIBI in the evaluation of single pulmonary nodules: a preliminary report.
(39/873)
BACKGROUND: Survival in bronchial carcinoma is closely related to the stage of the disease at the time of diagnosis and a single pulmonary nodule represents a potentially curable stage. This study was conducted to assess the feasibility of using Tc-99m labelled 2-methoxy isobutyl isonitrile (MIBI) to differentiate benign from malignant single pulmonary nodules. METHODS: A prospective study was conducted in the outpatient pulmonary clinic at the Cleveland Clinic Foundation. Twenty five patients with single pulmonary nodules considered indeterminate by their physicians and undergoing a procedure for tissue diagnosis were evaluated by Tc-99m MIBI SPECT scanning prior to definitive testing. Assessment of MIBI uptake was done qualitatively (subjectively) and quantitatively and correlated with the histopathology and nodule size. RESULTS: Of the 21 patients with malignant lesions, 18 had increased uptake of MIBI corresponding to the location of the nodule and were considered positive. The predominant tumour types were large cell (n = 5) and adenocarcinoma (n = 10). All four patients with benign lesions had negative MIBI scans. For malignancy the overall specificity was 100%, sensitivity was 85.7%, positive predictive value was 100%, and negative predictive value was 57%. Quantitative uptake of MIBI correlated with the diameter of the nodule with a correlation coefficient of 0.61 by Spearman's rank sum test. This relationship was statistically significant (p = 0.02). CONCLUSION: This preliminary study suggests that Tc-99m MIBI has a very high specificity and positive predictive value for malignant single pulmonary nodules and might be a useful non-invasive diagnostic modality in their management. (+info)
Evaluation of cardiac function in myocardial infarction patients by ECG 99mTc-MIBI gated SPECT using a three-dimensional perfusion/motion map procedure.
(40/873)
Three-dimensional (3D) radionuclear myocardial imaging has improved the evaluation of left ventricular wall motion. However, there have been no studies evaluating left ventricular function using 3D-perfusion/motion map techniques. We hypothesized that the 3D-perfusion/motion map could accurately evaluate left ventricular wall motion even in patients with a history of myocardial infarction. Electrocardiogram (ECG)-gated single photon emission computed tomography (SPECT) using 99mTc-methoxy isobutyl isonitrile (MIBI) was performed in 20 patients with a history of myocardial infarction who underwent left ventriculography. Myocardial imaging data were collected during ECG-gated SPECT using a 3-headed gamma camera. Reconstructed 3D SPECT images were oriented to correspond to standard left ventriculography views (right anterior oblique and left anterior oblique projections), and the shortening fraction (SF) was calculated using the center line method. The SF and left ventricular ejection fraction from 3D SPECT images were compared with those determined by left ventriculography. There was a significant correlation between left ventriculography and the 3D-perfusion/motion map procedure in determining SF for all regions of the left ventricle except the anterobasal and posterior segments by using the Bland and Altman method. The 3D-perfusion/motion map procedure offers the advantage that the influences of contraction-related myocardial torsion and three-dimensional compression are minimized. In addition, this method facilitates evaluation of images from nonstandard projections. We conclude that this method may be useful for evaluating left ventricular function. (+info)