Octreotide scintigraphy: a prerequisite for liver transplantation for metastatic gastrinoma.
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Adult↗
Biomedical subjects
S Eberl
Publications and source records attributed to S Eberl.
Differences in airway closure between normal and asthmatic subjects measured with single-photon emission computed tomography and technegas.
The absence of a maximal dose-response plateau as well as gas trapping and increases in closing capacity (CC) suggest that increased airway closure is an important mechanical abnormality of asthmatic airways. We compared the extent and distribution of airway closure in 13 normal and in 23 asthmatic subjects. Airway closure (LVclosed) was measured with single-photon emission computed tomography (SPECT) and an inhaled Technegas bolus as the percentage of lung volume without Technegas (LVtrans), and with CC, using nitrogen washout. LVclosed was compared in the apical, middle and lower zones, each being of equal vertical height. Values of mean LVclosed +/- 95% confidence interval (CI) were similar in normal (30 +/- 6.0% LVtrans) and asthmatic subjects (30 +/- 7.8% LVtrans). In normal subjects, LVclosed correlated with both age (r = 0.89, p < 0. 01) and CC (r = 0.86, p < 0.01), was more extensive in the lower zone (58 +/- 18.8% LVtrans, p < 0.01) than in the middle and upper zones (17 +/- 8.7% and 26 +/- 8.2 LVtrans, respectively), and increased with age in both the middle and lower zones (r = 0.94 and r = 0.90, respectively, p < 0.01). In asthmatic subjects, LVclosed did not correlate with age; was greatest in the lower zone, intermediate in the middle zone, and lowest in the apical zone (59 +/- 13.2%, 22 +/- 5.8%, and 12 +/- 4.4% LVtrans, respectively, p < 0. 01); and correlated weakly with age in the middle zone only (r = 0. 46, p < 0.05). We conclude that there is a predictable pattern of airway closure in normal subjects and that it is primarily influenced by pulmonary elastic recoil. This pattern is lost in asthmatic subjects. This may be explained by an increased range of closing pressures and a patchy distribution of airway closure, probably secondary to allergic inflammation.
Administration, Inhalation↗
Effects of scatter and attenuation correction on quantitative assessment of regional cerebral blood flow with SPECT.
UNLABELLED: Appropriate corrections for scatter and attenuation correction are prerequisites for quantitative SPECT studies. However, in most cerebral SPECT studies, uniform attenuation in the head is assumed, and scatter is usually neglected. This study evaluated the effect of attenuation correction and scatter correction on quantitative values and image contrast. METHODS: Studies were performed in six normal volunteers (ages 22-26 yr) following intravenous 123I-IMP administration using a rotating, dual-head gamma camera. A transmission scan was acquired with a 99mTc rod source (74 MBq) placed at the focus of a symmetrical fanbeam collimator. Data were reconstructed using two attenuation coefficient (mu) maps: quantitative mu map from the transmission scan and a uniform mu map generated by edge detection of the reconstructed images. Narrow and broad beam mu values were used with and without scatter correction, respectively. Scatter was corrected with transmission-dependent convolution subtraction and triple-energy window techniques. Quantitative rCBF images were calculated by the previously validated IMP-autoradiographic technique, and they were compared with those obtained by (15)O-water and PET. SPECT and PET images were registered to MRI studies, and rCBF values were compared in 39 ROIs selected on MRI. RESULTS: Clear differences were observed in rCBF images between the measured and constant mu maps in the lower slices due to the airways and in the higher slices due to increased skull attenuation. However, differences were < 5% in all cerebral tissue regions, thus assumption of uniform mu introduces little bias. The scatter correction was found to increase the image contrast significantly, i.e., rCBF increased by 20%-30% in gray matter and decreased in white matter regions by 10%-20% after scatter correction, increasing gray-to-white ratio to be close to that of PET measurement. The rCBF values from the two scatter correction were not significantly different, but the triple-energy window technique suffered from increased noise. After scatter correction, rCBF values were in good agreement with those measured by PET. CONCLUSION: This study shows little loss in accuracy results from assuming uniform mu map. However, scatter correction is required for the quantitative rCBF values and gray-to-white ratios to approach those of PET.
Adult↗
Noninvasive quantitation of cerebral blood flow using oxygen-15-water and a dual-PET system.
UNLABELLED: Measurement of the arterial input function is essential for quantitative assessment of physiological function in vivo using PET. However, frequent arterial blood sampling is invasive and labor intensive. Recently, a PET system has been developed that consists of two independent PET tomographs for simultaneously scanning the brain and heart, which should avoid the need for arterial blood sampling. The aim of this study was to validate noninvasive quantitation with this system for 15O-labeled compounds. METHODS: Twelve healthy volunteers underwent a series of PET studies after C15O inhalation and intravenous H2(15)O administration using a Headtome-V-Dual tomograph (Shimadzu Corp., Kyoto, Japan). The C15O study provided gated blood-pool images of the heart simultaneously with quantitative static blood-volume images of both the brain and heart. Weighted-integrated H2(15)O sinograms were acquired for estimating rate constant (K1) and distribution-volume (Vd) images in the brain, in addition to single-frame sinograms for estimating autoradiographic cerebral blood flow images. Noninvasive arterial input functions were determined from the heart scanner (left ventricular chamber) according to a previously developed model and compared directly to invasive input functions measured with an on-line beta probe in six subjects. RESULTS: The noninvasive input functions derived from this PET system were in good agreement with those obtained by continuous arterial blood sampling in all six subjects. There was good agreement between quantitative values obtained noninvasively and those using the invasive input function: average autoradiographic regional cerebral blood flow was 0.412 +/- 0.058 and 0.426 +/- 0.062 ml/min/g, K1 of H2(15)O was 0.416 +/- 0.073 and 0.420 +/- 0.067 ml/min/ml and Vd of H2(15)O was 0.800 +/- 0.080 and 0.830 +/- 0.070 ml/ml for the noninvasive and invasive input functions, respectively. In addition to the brain functional parameters, the system also simultaneously provided cardiac function such as regional myocardial blood flow (0.84 +/- 0.19 ml/min/g), left ventricular volume (132 +/- 22 mm at end diastole and 45 +/- 14 ml at end systole) and ejection fraction (66% +/- 5%). CONCLUSION: This PET system allows noninvasive quantitation in both the brain and heart simultaneously without arterial cannulation, and may prove useful in clinical research.
Adult↗
Evaluation of two population-based input functions for quantitative neurological FDG PET studies.
The conventional measurement of the regional cerebral metabolic rate of glucose (rCMRGlc) with fluorodeoxyglucose (FDG) and positron emission tomography (PET) requires arterial or arterialised-venous (a-v) blood sampling at frequent intervals to obtain the plasma input function (IF). We evaluated the accuracy of rCMR-Glc measurements using population-based IFs that were calibrated with two a-v blood samples. Population-based IFs were derived from: (1) the average of a-v IFs from 26 patients (Standard IF) and (2) a published model of FDG plasma concentration (Feng IF). Values for rCMRGlc calculated from the population-based IFs were compared with values obtained with IFs derived from frequent a-v blood sampling in 20 non-diabetic and six diabetic patients. Values for rCMRGlc calculated with the different IFs were highly correlated for both patient groups (r > or = 0.992) and root mean square residuals about the regression line were less than 0.24 mg/min/100 g. The Feng IF tended to underestimate high rCMRGlc. Both population-based IFs simplify the measurement of rCMRGlc with minimal loss in accuracy and require only two a-v blood samples for calibration. The reduced blood sampling requirements markedly reduce radiation exposure to the blood sampler.
Adult↗
Airway closure measured by a technegas bolus and SPECT.
Absence of a maximal dose-response plateau and mathematical modeling suggest that asthmatic airways close during bronchoconstriction. Finding segmental areas affected by closure would be important in understanding asthmatic airway function. The aim of this study was to evaluate single-photon emission computed tomography (SPECT) as a method of investigating airway closure. Simultaneous SPECT transmission and emission studies were performed on a thoracic phantom to develop analysis methodology, and on 13 normal subjects after they inhaled a Technegas bolus from residual volume (RV), to measure airway closure. Single-breath nitrogen test values and lung volumes were measured. Airway closure was defined as the percent of Technegas-free lung volume (LVclosed). The mean error +/- 95% CI of the error, as determined by transmission scan, was 1.1 ml +/- 165 ml (0.8% +/- 15% lung volume) in the phantom studies, and 112 ml +/- 419 ml (4% +/- 31% of supine functional residual capacity [FRC]) in the human studies. LVclosed correlated with closing capacity (r = 0.86, p < 0.01 ) and closing volume (r = 0.86, p < 0.01), but not with RV/total lung capacity (TLC). This study indicates that simultaneous SPECT emission and transmission scans, using a Technegas bolus, are a valid method of measuring airway closure in vivo, with the added advantage of providing three-dimensional data that allow the detection of small, discrete areas of airway closure and determination of their volumes and shapes.
Adult↗
Inhalation of dry-powder mannitol increases mucociliary clearance.
Inhalation of hypertonic saline stimulates mucociliary clearance (MCC) in healthy subjects and those with obstructive lung disease. We investigated the effect of inhaling the osmotic agent mannitol on MCC. We used a dry-powder preparation of mannitol British Pharmacopea (BP) which was encapsulated and delivered using a Dinkihaler. MCC was measured for 75 min in six asthmatic and six healthy subjects on two occasions before and after the mannitol inhalation or its control, using 99mTc-sulphur colloid and a gamma camera. The inhaled dose of mannitol was 267+/-171 mg (mean+/-SD) and 400 mg and the percentage fall in forced expiratory volume in one second (FEV1) was 22+/-3 and 4+/-2% in the asthmatic and healthy subjects, respectively. The total clearance in the whole right lung for the 60 min from the start of inhalation of mannitol was greater by 263+/-11.9% in the asthmatic and 18.1+/-4.9% in the healthy subjects compared to the control. The total clearance over 75 min was 54.7+/-9.6% and 33.6+/-9.4% on the mannitol and control day (p<0.002), respectively, in the asthmatic subjects and 40.5+/-7.1% and 24.8+/-7.8% (p<0.002) in the healthy subjects. In conclusion, inhalation of dry-powder mannitol increases mucociliary clearance in asthmatic and healthy subjects and may benefit patients with abnormal mucociliary clearance.
Administration, Inhalation↗
Monte Carlo and experimental evaluation of accuracy and noise properties of two scatter correction methods for SPECT.
Scatter correction is a prerequisite for quantitative SPECT, but potentially increases noise. Monte Carlo simulations (EGS4) and physical phantom measurements were used to compare accuracy and noise properties of two scatter correction techniques: the triple-energy window (TEW), and the transmission dependent convolution subtraction (TDCS) techniques. Two scatter functions were investigated for TDCS: (i) the originally proposed mono-exponential function (TDCSmono) and (ii) an exponential plus Gaussian scatter function (TDCSGauss) demonstrated to be superior from our Monte Carlo simulations. Signal to noise ratio (S/N) and accuracy were investigated in cylindrical phantoms and a chest phantom. Results from each method were compared to the true primary counts (simulations), or known activity concentrations (phantom studies). 99mTc was used in all cases. The optimized TDCS(Gauss) method overall performed best, with an accuracy of better than 4% for all simulations and physical phantom studies. Maximum errors for TEW and TDCS(mono) of -30 and -22%, respectively, were observed in the heart chamber of the simulated chest phantom. TEW had the worst S/N ratio of the three techniques. The S/N ratios of the two TDCS methods were similar and only slightly lower than those of simulated true primary data. Thus, accurate quantitation can be obtained with TDCS(Gauss), with a relatively small reduction in S/N ratio.
Air↗
Inhalation of hypertonic saline aerosol enhances mucociliary clearance in asthmatic and healthy subjects.
Hyperosmolarity of the airway surface liquid (ASL) has been proposed as the stimulus for hyperpnoea-induced asthma. We found previously that mucociliary clearance (MCC) was increased after isocapnic hyperventilation (ISH) with dry air, and we proposed that the increase related to transient hyperosmolarity of the ASL. We investigated the effect of increasing the osmolarity of the ASL on MCC, by administering an aerosol of concentrated salt solution. MCC was measured using 99mTc-sulphur colloid, gamma camera and computer analysis in 12 asthmatic and 10 healthy subjects on three separate days, involving administration of each of the following: 1) ultrasonically nebulized 14.4% saline; 2) ultrasonically nebulized 0.9% saline; and 3) no aerosol intervention (control). The (mean +/- SD) volume of nebulized 14.4% saline was 2.2 +/- 1.2 mL for asthmatics and 3.2 +/- 0.7 mL for healthy subjects. This volume was delivered over a period of 5.4 +/- 1.3 and 6.4 +/- 0.7 min for asthmatic and healthy subjects, respectively. The airway response to 14.4% saline was assessed on a separate visit and the fall in forced expiratory volume in one second (FEV1) was 22 +/- 4% in the asthmatic and 3 +/- 2% in the healthy subjects. Compared to the MCC with the 0.9% saline and control, the hypertonic aerosol increased MCC in both groups. In asthmatic subjects, MCC of the whole right lung in 1 h was 68 +/- 10% with 14.4% saline vs 44 +/- 14% with 0.9% saline and 39 +/- 13% with control. In healthy subjects, MCC of the whole right lung in 1 h was 53 +/- 12% with 14.4% saline vs 41 +/- 15% with 0.9% saline and 36 +/- 13% with control. We conclude that an increase in osmolarity of the airway surface liquid increases mucociliary clearance both in asthmatic and healthy subjects. These findings are in keeping with our previous suggestion that the increase in mucociliary clearance after isotonic hyperventilation with dry air is due to a transient hyperosmolarity of the airway surface liquid.
Administration, Inhalation↗
Validation of postinjection transmission measurements for attenuation correction in neurological FDG-PET studies.
UNLABELLED: Accurate estimation of local cerebral metabolic rate of glucose utilization (LCMRGlu) with PET requires a separate measurement of photon attenuation using a transmission source that extends study duration. The feasibility of postinjection transmission, (PIT) scanning has been demonstrated but not previously validated in humans. METHODS: Preinjection and postinjection transmission scans were performed in 26 patients undergoing routine [18F]fluorodeoxyglucose (FDG) neurological PET. The PIT data were processed with two methods: One estimated emission contamination using an independent emission scan (PITind); the other estimated the contamination directly from the PIT scan, using simultaneously acquired emission data for subtraction (PITsim). These methods were compared with measured attenuation correction (AC) using preinjection transmission data (ACpre) and calculated AC (ACcalc). After reconstruction, image data were reformatted to fit a standard brain atlas to facilitate analysis of the region of interest and to allow subtraction of datasets averaged over all subjects. RESULTS: The ratios of LCMRGlu values with respect to those obtained by the ACpre method ranged from 0.98 to 1.06 (mean +/- s.d., 1.01 +/- 0.02) for PITind, from 0.96 to 1.04 (mean 0.99 +/- 0.02) for PITsim and from 0.77 to 1.12 (mean 0.96 +/- 0.07) for ACcalc. Both PIT methods agreed well with the ACpre method, whereas ACcalc gave rise to appreciable bias in structures near thick bone or sinuses. CONCLUSION: Accurate quantitative estimates of LCMRGlu can be obtained using PIT measurements. The PIT methods shorten study duration and increase patient throughput. The PITsim method has the further advantage that it is not affected by tracer redistribution and can therefore be applied to tracers with relatively rapid kinetics in vivo.
Brain↗
Automated interstudy image registration technique for SPECT and PET.
UNLABELLED: We report the extended application of an automated computer technique for three-dimensional spatial registration of SPECT and PET studies. METHODS: The technique iteratively reslices a misaligned data set until the sum of the absolute differences (SAD) from a reference data set is minimized. The registration accuracy was assessed in Hoffman brain phantom studies collected with known misalignments and transmission studies of a thorax phantom with fiducial markers. The SAD was compared with three other cost functions: stochastic sign change criterion, sum of products and standard deviation (s.d.) of ratios. In clinical neurological and myocardial perfusion studies, registration accuracy was estimated from the relative locations of landmarks in the reference and registered data sets. RESULTS: Registration accuracy in the Hoffman brain phantom studies was -0.07 +/- 0.46 mm (mean +/- s.d.) for translations and -0.01 +/- 0.20 degrees for rotations, with maximum translation and rotation errors of 1.2 mm and 0.8 degree, respectively. The SAD was the most accurate and reliable cost function. Registration errors in the thorax phantom were 3.1 +/- 1.7 mm. Mean accuracy in the neurological studies, estimated from landmark pairs, was 2.0 +/- 1.1 mm for SPECT to SPECT and 1.8 +/- 1.1 mm for PET to SPECT registrations. Average registration accuracy in 201Tl myocardial perfusion studies was 2.1 +/- 1.2 mm. CONCLUSION: Our registration method (a) provided accurate registrations for phantom and clinical SPECT and PET studies, (b) is fully automated, (c) simplifies comparison of data sets obtained at different times and with different modalities, and (d) can be applied retrospectively.
Algorithms↗
Simultaneous emission and transmission measurements for attenuation correction in whole-body PET.
UNLABELLED: We describe a methodology for measuring and correcting for attenuation in whole-body PET using simultaneous emission and transmission (SET) measurements. METHODS: The main components of the methodology are: (a) sinogram windowing of low activity (< or = 50 MBq) rotating 68Ge/Ga rod sources, (b) segmented attenuation correction (SAC) and (c) maximum likelihood reconstruction using the ordered subsets EM (OS-EM) algorithm. The methods were implemented on a whole-body positron emission tomograph. Quantitative accuracy and the signal-to-noise ratio (SNR) were measured for a thorax-tumor phantom as functions of acquisition time (range: 2-20 min per position). RESULTS: When a typical rod source activity (200 MBq 68Ge/Ga) was used, emission SNR was 60% lower in simultaneous than in separate measurements. The difference was only 14% when the rods contained 45 MBq 68Ge/Ga. The SNR was further improved by SAC in conjunction with OS-EM reconstruction and the relative gain increased with increasing acquisition time. Quantitative estimates of tumor, liver and lung radioactivity agreed with values obtained from a separate high count measurement to within 8%, independent of acquisition time. CONCLUSION: Attenuation correction of whole-body PET images is feasible using SET measurements. There is good quantitative agreement with conventional methods and increased noise is offset by the use of SAC and OS-EM reconstruction.
Adult↗
A method to quantitate cerebral blood flow using a rotating gamma camera and iodine-123 iodoamphetamine with one blood sampling.
A method has been developed to quantitate regional cerebral blood blow (rCBF) using iodine-123-labelled N-isopropyl-p-iodoamphetamine (IMP). This technique requires only two single-photon emission tomography (SPET) scans and one blood sample. Based on a two-compartment model, radioactivity concentrations in the brain for each scan time (early: t(e); delayed: td are described as: [formula: see text] respectively, where x denotes the convolution integral; Ca(t), the arterial input function; f, rCBF; and Vd, the regional distribution volume of IMP. Calculation of the ratio of the above two equations and a "table look-up" procedure yield a unique pair of rCBF and Vd for each region of interest (ROI). A standard input function has been generated by combining the input functions from 12 independent studies prior to this work to avoid frequent arterial blood sampling, and one blood sample is taken at 10 min following IMP administration for calibration of the standard arterial input function. This calibration time was determined such that the integration of the first 40 min of the calibrated, combined input function agreed best with those from 12 individual input functions (the difference was 5.3% on average). This method was applied to eight subjects (two normals and six patients with cerebral infarction), and yielded rCBF values which agreed well with those obtained by a positron emission tomography H2(15)O autoradiography method. This method was also found to provide rCBF values that were consistent with those obtained by the non-linear least squares fitting technique and those obtained by conventional microsphere model analysis. The optimum SPET scan times were found to be 40 and 180 min for the early and delayed scans, respectively. These scan times allow the use of a conventional rotating gamma camera for clinical purposes. Vd values ranged between 10 and 40 ml/g depending on the pathological condition, thereby suggesting the importance of measuring Vd for each ROI. In conclusion, optimization of the blood sampling time and the scanning time enabled quantitative measurement of rCBF with two SPET scans and one blood sample.
Aged↗
A scanning line source for simultaneous emission and transmission measurements in SPECT.
A scanning collimated line source for simultaneously acquiring emission and transmission data from a gamma camera has been developed. The line source is microprocessor-controlled and incorporates hardware to electronically window the spatial gamma camera signals in order to separate the emission signals of the subject from transmission signals from the line source. The device improves upon the previously described emission-transmission scanning technique using a flood source in three ways: (1) it overcomes the limitation that the transmission radionuclide must have a lower energy than the emission radionuclide; (2) it provides narrow-beam (scatter free) attenuation measurements of the subject being examined; and (3) it reduces the radiation exposure to staff. Attenuation coefficients for an elliptocal water-filled phantom were measured to be mu = 0.15 +/- 0.01 cm-1. The technique has been validated in phantom and human studies using a range of radionuclide combinations and imaging geometries and gives equivalent results using separate and simultaneous acquisitions.
Female↗
Use of technetium-HMPAO to demonstrate changes in cerebral blood flow reserve following carotid endarterectomy.
Cerebral perfusion through stenosed internal carotid arteries is usually maintained by autoregulation. However, flow reserve may be reduced, suggesting hemodynamically significant stenosis, and such reduction should be improved by carotid endarterectomy. This concept was studied in 20 subjects with unilateral internal carotid artery stenosis (major stenosis greater than or equal to 70%, minor stenosis less than or equal to 50%). Thirteen had experienced recent transient ischemic attacks and seven had no definite focal symptoms. Subjects underwent Tc-HMPAO cerebral SPECT during acetazolamide dysautoregulation before and after internal carotid endarterectomy. Nine (45%) had perfusion defects that improved after surgery, suggesting surgery had improved cerebral flow reserve. Seven had defects that did not improve after surgery. Four had worsened or new defects after surgery, suggesting perioperative infarcts. The relatively large proportion of patients with improved cerebral blood flow reserve after surgery suggests that this technique may have a significant role to play in assessing which patients might benefit from carotid endarterectomy.
Aged↗
Corticosteroid effects on proximal femur bone loss.
Prolonged high-dose corticosteroid therapy is known to result in an increased risk of osteoporotic fracture. Reductions in bone density have been demonstrated at the distal radius and lumbar spine in patients receiving corticosteroids; however there have been few studies of bone density in the hip (the most important site of osteoporotic fracture) in this context. To examine the effect of corticosteroids on the hip we measured bone mineral density (BMD) by dual-photon absorptiometry at three sites in the proximal femur as well as the lumbar spine in 32 patients aged 18-77 years who had been treated with corticosteroids (mean daily prednisone dose 12.7 mg) for up to 23 years. BMD was compared with the expected values using age regressions in normal subjects. BMD was significantly reduced in the femoral neck, Ward's triangle, and the trochanteric region (p less than 0.001 all sites). In the lumbar spine BMD was also significantly reduced (p less than 0.001). We also measured BMD serially in 29 patients receiving corticosteroids. BMD measurements were made in 12 patients who had already been treated with long-term corticosteroids at the time of first BMD measurement (chronic group) and from the commencement of corticosteroid therapy in 17 patients (acute group). The mean (+/- SEM) change in BMD (g/cm2 per year) in the lumbar spine and femoral neck were 0.006 +/- 0.006 and -0.021 +/- 0.007, respectively, for the chronic group and -0.02 +/- 0.005 and -0.039 +/- 0.006 for the acute group.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Reproducibility of radionuclide left ventricular ejection fraction in patients awaiting cardiac transplantation.
Radionuclide-derived left ventricular ejection fraction (LVEF) is used to assess LV systolic function, to follow trends in the natural history of dilated cardiomyopathy, and to prioritize patients waiting for cardiac transplantation. Reproducibility of LVEF at extremely low levels has not, however, been reported. To assess the reproducibility of radionuclide LVEF at levels below 0.30 EF U, 17 highly symptomatic patients (NYHA Class III/IV) with dilated cardiomyopathy were studied on two occasions, 72 hours apart. Sequential scans were analyzed by two independent observers. Mean LVEF was 0.18 +/- 0.06 U (scan 1) and 0.17 +/- 0.06 U (scan 2). Interoperator reproducibility (SD) was 0.03 U (R = 0.76), interscan reproducibility (SD) was 0.03 U (R = 0.62), and overall reproducibility (SD) was 0.04 U (R = 0.50). The interobserver variation of 0.03 (actually 0.027) was just over one half that seen in normal volunteers (variation 0.05, n = 29) studied previously in this department. A change of greater than or equal to 0.08 U (2SD) in either direction is highly likely to represent a real change in LV function in those with LVEF less than or equal to 0.30 units, compared with the change of at least 0.10 units required in those with normal LV function. Lower interobserver and interscan reproducibility should be taken into account when interpreting sequential scans in patients with severe LV dysfunction.
Adolescent↗
Dual-photon bone densitometry in normal Australian women: a cross-sectional study.
Osteoporosis is a major health problem in Australia, as it is in most Western societies. Bone mineral density in the spine and femoral neck are accurate indicators of osteopenia and thus useful indicators of the risk of a fracture. Dual-photon absorptiometry is a non-invasive technique that allows the accurate quantitation of bone mineral density in the lumbar vertebrae and proximal femur with a low radiation exposure. The increasing availability of this technique dictates the requirement for "normal" ranges and quality control. We report here lumbar vertebral and proximal femur bone mineral density as measured by dual-photon absorptiometry in 179 normal Australian women. Forearm bone mineral content in these subjects, as measured by single-photon absorptiometry, is also presented. There was a relative stability of lumbar bone mineral density and forearm bone mineral content before the menopause, after which there was an age-related decline. On the other hand, bone mineral density at all three sites in the proximal femur showed an age-related decline throughout adult life. Intraoperator variability in calculated bone mineral density did not exceed 2.3%. The requirement for correct positioning of the patient is illustrated. The data allow statistical analysis and the development of normal ranges. They provide an Australian base against which individual patient values can now be compared.
Adult↗