Search

Objectives Nicotine therapy might improve the course of Parkinson's disease. This observational study evaluated the performance of dopamine transporter imaging in follow-up patients under nicotine therapy. Methods Six Hoehn and Yahr stage III patients underwent 123I-FP-CIT imaging prior to, 3 months, and 1 year after the onset of nicotine therapy. Nicotine was administered transdermally with increasing daily doses during 3 months (up to 105 mg/day) and decreased progressively. On co-registered magnetic resonance imaging, striatal regions of interest were drawn and binding potentials of 123I-FP-CIT were calculated.Changes in Unified Parkinson's Disease Rating Scale-III over time were compared with binding potentials using regression analysis. Results All patients improved motor scores at 3 months (-65 +/- 22% 'off', -89 +/- 12% 'on') and most received fewer dopaminergic drugs (-30% dosage in average). Motor improvement persisted to a lesser extent at 1 year(-39 +/- 31% 'off', -13 +/- 43% 'on'), partly because one patient stopped the treatment. Interestingly, the decrease in binding potentials (-4.0 +/- 10.5%) was slower than that expected in Parkinsonian patients (usually -10% per year) and was inversely correlated with Unified Parkinson's Disease Rating Scale-III improvement, r= 0.83 'off' and 0.91 'on'. Conclusion This observational study emphasizes a potential effect of nicotine therapy on striatal dopamine transporter density, which may be interpreted as direct pharmacological effect or deceleration of neuronal loss.

Background and aims A significant decrease of left ventricular ejection fraction (LVEF) at stress has been reported with 99Tc(m) gated single-photon emission computed tomography (gSPECT) in severe myocardial stunning up to 1 h after exercise. This study was designed to show whether 201Tl gSPECT can measure LVEF evolution from rest to stress in routine examination and give additional information to perfusion interpretation since acquisition starts immediately after stress test. Methods Post-exercise and rest 201Tl gSPECT were performed in 187 patients with suspected coronary artery disease. Myocardial perfusion was quantified by 20-segment analysis. Patients were divided into four groups according to their summed perfusion score, reversibility rate and electrocardiographic findings, i.e. in order of severity: I = normal perfusion, II = fixed defect owing to a myocardial infarction, III = full reversible ischaemia, and IV = partial reversible ischaemia. LVEF was calculated by Germano's automatic algorithm. Results Normal subjects (n = 29) and infarcted patients (n = 34) showed a significant LVEF increase between rest and stress, +7 +/- 9% and +5 +/- 7% respectively. In full reversible ischaemic patients (n = 46), stress LVEF showed no increase (+1 +/- 8%) and this group was statistically different from both group I and group II. Furthermore, when ischaemia was partially reversible (n = 31), LVEF decreased significantly (-3 +/- 8%), particularly when exercise tests were abnormal (-4 +/- 8%). Group IV was statistically different from groups I and II. Conclusions Good agreement exists between the severity of ischaemic perfusion pattern and LVEF degradation at stress, which is consistent with previously published data using 99Tc(m) gSPECT. Additionally, the use of 201Tl for immediate post-exercise imaging allows the observation of a physiological LVEF increase in normal and infarcted patients.

A peripheral perfusion tracer injection at the time of coronary occlusion during percutaneous transluminal coronary angioplasty (PTCA) may delineate the myocardial 'area at risk' related to a given artery. To evaluate the location, size and severity of the corresponding scintigraphic defects, we conducted a prospective study of 36 patients who received a 99Tcm-sestamibi injection during single-vessel coronary angioplasty (PTCA = 18 LAD, 16 RCA and 2 LCX) followed by SPET. For comparison, a reference group of 36 successive patients examined during the early phase of myocardial infarction (MI), matched for the same vascular territories (18 anterior, 16 inferior and 2 lateral), were analysed in the same way after standard stress/reinjection 201Tl SPET. The imaging characteristics of both groups showed excellent agreement as well degree of uptake defects, in terms of topography and extent. A defect index, taking into account both size and severity, was in the same range for PTCA and MI patients (mean +/- standard deviation): for LAD vs anterior = 28.4 +/- 13.5% (PTCA), 27.1 +/- 12.2% (MI-stress) and 24.2 +/- 10.0% (MI-reinjection); for RCA vs inferior = 15.5 +/- 10.2% (PTCA), 14.7 +/- 9.7% (MI-stress) and 13.2 +/- 8.2% (MI-reinjection). Sectoral correlations between PTCA and MI groups were also highly significant.

Early diagnosis of carcinoma of the breast is currently attempted by mammography and physical examination which together have a sensitivity of 85%. Mammography has a positive predictive value of only 15 to 40 percent. The usefulness of scintimammography for the detection of carcinoma of the breast has been studied which demonstrated improved specificity compared to conventional mammography. In future, with the development or dedicated breast imager and new targeted radiopharmaceuticals, we can achieve detection of smaller than 1 cm carcinoma. This type of imaging enables us to detect cancer at its 'pre-anatomic' stage.

The assessment of lung ventilation by radionuclide imaging has proved useful for the optimization of aerosol therapy in children with cystic fibrosis. Further analysis of lung perfusion may provide additional information.Quantitative analysis of regional lung aerosol distribution (Tc phytates) and perfusion (Tc macroaggregates) homogeneity was performed in 18 children with cystic fibrosis, using the third and fourth spatial moments (skew and Kurtosis) of count distribution. Patients were chosen from a prospective study whose goal was to compare the efficacy of two nebulization methods of a radiolabelled aerosol: one session involved a nebulizer activated by patient inspiratory flow (control session), whereas the other involved a nebulizer powered by a pressure support device (PS session).Quantitative regional distribution of perfusion was similar to aerosol distribution, although skew and Kurtosis were lower, indicating better homogeneity. Perfusion skew was inversely correlated with pulmonary volumes and Shwachman score, even more significantly than ventilation skew. Using receiver operating characteristic curve analysis, a perfusion skew threshold of 0.67 was predictive of disease severity (FEV1or =60% or FEV160%) with 86% sensitivity and 91% specificity. Furthermore, same skew threshold allowed the identification of patients who were 'PS responders' (greater amount of radioactivity deposited after the PS session) or 'PS non-responders' with 80% sensitivity and 77% specificity.Quantification of regional lung perfusion is easy to perform and heterogeneity of the distribution is closely correlated to disease severity. Moreover, perfusion skew can identify patients who are likely to benefit from pressure support (to optimize aerosol therapy) and may be helpful for orienting potential non-responders towards alternative therapies.

This study presents a new tool for the visualization and analysis of three-dimensional (3-D) cardiac single-photon emission computed tomography (SPECT). The first step consisted of computing the 3-D pseudo-skeleton of a binarized myocardium and, using the skeleton points, to design a bullet model (half ellipsoid prolonged by a cylinder). Afterwards, this model was used to drive the warping of the 3-D myocardium, initially egg-shaped, into a thick, flat disc using the thin-plate splines as deformation method. Hence, instead of achieving several rotations of the initial egg-shaped volume to have an idea on the myocardial outer face (epicardial) only, the whole myocardium is seen by looking either on top of the disc-shaped transformed myocardium (epicardial surface) or underneath for the inner face (endocardial). This new shape permitted us to localize any type of defect and to evaluate its extent and depth just by a single glance. A detailed analysis, achieved after stripping away this shape in about 10 layers, allowed us to evaluate the defect extent layer by layer and to determine whether the defect involves the totality of the myocardium layers. Finally, its flattening following the ventricular long-axis led to a summed bull's eye.

Invasive and non-invasive methods exist to assess left ventricular compliance (LVC). This work has two parts, one experimental and one clinical. We estimated left chamber stiffness in dogs by using volume data from radionuclide ventriculography (RNV) and left ventricular pressure data, synchronized with a gating system to the intraventricular dp/dt max to obtain volume and pressure data from a mean cardiac cycle. In five dogs after acute experimental ischaemia, the modulus chamber stiffness Kp rose from 30.2 +/- 4.4 to 55.4 +/- 5.9 (P < 0.01). In 10 dogs with experimental infarction after intra-aortic balloon pumping, Kp decreased from 33.7 +/- 5.0 to 15.5 +/- 3.9 (P < 0.01) and in five dogs with experimental infarction, after intravenous infusion of sodium nitroprusside, Kp decreased from 41.4 +/- 5.5 to 22.2 +/- 2.8 (P < 0.01). In eight normal volunteers and in 20 postmyocardial infarction patients, we estimated a parameter reflecting the LVC by using volume data with blood flow velocity at the mitral valve annulus. Assuming that the mitral flow-velocity variation reflects LV pressure changes, the formula LVC = (dv/dt)/(dp-dt) becomes (dv/dt)/(df/dt) = dv/df. Values obtained in normals were 0.841 +/- 0.295 m-1s and after myocardial infarction 0.331 +/- 0.10 m-1s. Both methods allow clear separation in groups of animals or patients according to the expected changes in LVC or stiffness.

The purpose of this work is to assess the contribution of factor analysis to the interpretation of dynamic lymphoscintigraphy. Twenty six adult patients with a lower limb lymphoedema and five control patients were studied. The technique involved a 3 mCi lymphovectoscint* 99Tcm-labelled ammonium sulphur colloid, bilateral pedal subcutaneous injection. Recording consisted of 40 consecutive 1-min frames of both legs followed by static pictures of each leg and pelvis at 40 min and 4 h after injection. The analysis of static pictures allowed a classification of patients into three groups: enhanced pattern, hypoplasia and dermic reflux. To evaluate better the different kinetic components of the sequential pictures, a factorial analysis (FA) software package was used. FA processing enabled the extraction from the dynamic series of different dynamic components, factorial curves and their associated factorial images which represent the anatomic structures with the same temporal behaviour. In each pattern the results of dynamic recording and of three FA factors were compared. FA provides an analytical temporal and spatial description of the dynamic sequence by extracting the different kinetic components; it yields a better differentiation of vessel and interstitium activity. It also provides some clues towards the understanding of oedema physiopathology and is of potential interest for the management of lymphoedema.

Summary Gastro-oesophageal reflux (GOR) was studied by continuous 1 h recording and 4 h pictures after a 99Tcm-labelled sulphocolloid meal in 57 children. The GOR rate Re, pulmonary aspiration rate A and 60 min gastric emptying GE were calculated as a percentage of the initial activity G0. GOR was visualized in 46 children (Re mean value = 1.54%); pulmonary aspiration was detected in 13 children (A mean value = 0.09%). Higher Re values were correlated with positive barium studies (Re mean value = 1.84% versus 0.61% in negative barium studies), and with slower gastric emptying (GE = 27.6% in children with an Re higher than 3% versus 44.2% in children with an Re lower than 1% P These results show the role of gastric dysmotility in reflux genesis and suggest that reflux time could be of predictive value in oesophagitis risk in children with GOR. Early postprandial and short gastro-oesophageal reflux is physiological. Fasting, iterative and persistent reflux results in a pathological condition with the risk of pulmonary aspiration and oesophagitis.

In a group of 207 patients undergoing coronary angiography, myocardial scintigrams have been performed at rest (n = 95), after exercise testing (n = 50) or after dipyridamole vasodilation (n = 62). Pictures recorded in anterior and 45 degrees left anterior oblique projections have been analysed according to a model which divides each projection into 5 territories. Thallium uptake has been visually assessed using a three grade scale: 0 = normal uptake, + = sightly abnormal uptake, ++ = evident hypoactivity. With reference to angiography, sensitivity and specificity for prediction of coronary artery disease have been calculated in a classical way using three different criteria of positivity of increasing severity, and by a computerized method based on discriminant analysis. In the first case, sensitivity and specificity were highly dependent one on the other and, as could be expected, varied in opposite directions, a high sensitivity (89 to 100%) being only achieved by accepting a lack of specificity (33 to 57%). Discriminant analysis, on the contrary, provided for each type of protocol: rest, stress, dipyridamole and redistribution, a single optimized combination of sensitivity (74 to 87%) and specificity (92 to 100%). The corresponding point, when located on the receiver operating characteristics (ROC) diagram, demonstrated a clear improvement in diagnostic accuracy. The same method has been applied for discrimination, not only between normals and abnormals, but also between normals and patients with and without myocardial infarction (correct diagnosis in 50 to 68% of cases), and between normals and patients with single-, double- or triple-vessel disease (correct diagnosis in 17 to 65% of cases) with a high specificity (correct classification of normals in 86 to 100% of cases).

A prospective study is undertaken in order to demonstrate the ability of scintigraphy with a non compartmental analysis to quantitate the duodeno-gastric reflux. 24 patients have been examined, sitting in front of a gamma camera: 12 with an endoscopically proved reflux and 12 normal subjects or volunteers. About 15 min after an injection of 148 to 222 MBq 99Tcm-IDA they were given a meal labelled with 37 MBq 113Inm-DTPA. Images were recorded for 2 h. Equal size gastric and duodenal ROIs were selected over the duodenum and stomach, avoiding overlap with neighbouring organs. The reflux index based upon the occupancy principle is calculated from the gastric and duodenal curves. It is the ratio between the gastric and duodenal ROI IDA fluxes. The value of the reflux index is 3 +/- 1.8% in normal subjects and 45 +/- 33% in pathological cases. Our method, which does not require intubation, quantitatively evaluates biliary reflux independently of injected dose and hepatic or gallbladder function.