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F Prigent

Publications and source records attributed to F Prigent.

At least 55 records · Page 3Linked to original sources
PubMed1990

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease.

Technetium-99m (Tc-99m) sestamibi is a new myocardial perfusion imaging agent that offers significant advantages over thallium-201 (Tl-201) for myocardial perfusion imaging. The results of the current clinical trials using acquisition and processing parameters similar to those for Tl-201 and a separate (2-day) injection protocol suggest that Tc-99m sestamibi and Tl-201 single photon emission computed tomography (SPECT) provide similar information with respect to detection of myocardial perfusion defects, assessment of the pattern of defect reversibility, overall detection of coronary artery disease (CAD) and detection of disease in individual coronary arteries. Tc-99m sestamibi SPECT appears to be superior to Tc-99m sestamibi planar imaging because the former provides a higher defect contrast and is more accurate for detection of disease in individual coronary arteries. Research is currently under way addressing optimization of acquisition and processing of Tc-99m sestamibi studies and development of quantitative algorithms for detection and localization of CAD and sizing of transmural and nontransmural myocardial perfusion defects. It is expected that with the implementation of the final results of these new developments, further significant improvement in image quality will be attained, which in turn will further increase the confidence in image interpretation. Development of algorithms for analysis of end-diastolic myocardial images may allow better evaluation of small and nontransmural myocardial defects. Furthermore, gated studies may provide valuable information with respect to regional myocardial wall motion and wall thickening. With the implementation of algorithms for attenuation and scatter correction, the overall specificity of Tc-99m sestamibi SPECT should improve significantly because of a substantial decrease in the occurrence of attenuation-related image artifacts.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1990

Quantitative exercise thallium-201 rotational tomography for evaluation of patients with prior myocardial infarction.

The utility of stress-redistribution thallium-201 myocardial perfusion single-photon emission computed tomography (SPECT) in patients with a prior single myocardial infarction was studied in 66 patients who were tested by both SPECT and coronary angiography. SPECT was quantified by comparing the patients' circumferential count profiles to a previously established normal data base and by plotting the results onto a polar coordinate map that localized defects to the 3 major coronary artery territories. The pattern of reversibility of the quantitatively detected defects was assessed by consensus visual analysis. SPECT thallium-201 detected myocardial infarction in 62 of 66 patients (sensitivity = 94%). Sixty-five percent of the infarct zones showed some reversibility at 4-hour imaging which corresponded with angiographic evidence of flow to the infarct zones in 95.5% of cases. Late (18 to 24 hours) imaging, done in 26 patients, showed complete or partial reversibility of 29% of infarct zone segments which were nonreversible on 4-hour images. To improve specificity for detection of disease in coronary arteries supplying the non-infarct territories, new quantitative criteria were developed that took into consideration contiguity of defects with the infarct zone. Accuracy for detection of patients with multivessel coronary disease by quantitative thallium-201 SPECT was 86%, which was significantly higher than those of the clinical response to exercise (48%), the exercise electrocardiographic response (56%) or their combination (65%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Quantitative analysis of tomographic stress thallium-201 myocardial scintigrams: a multicenter trial.

The accuracy of the previously developed and validated Cedars-Sinai Medical Center (CSMC) computer program for quantitative analysis of thallium-201 (201TI) stress myocardial tomograms was assessed in a multicenter trial consisting of 242 patients with coronary angiography and 76 with a low likelihood (LL) of coronary artery disease (CAD) involving various cameras, computers, and operators. The program utilized gender-matched normal limits developed from 35 LL patients at CSMC. The multicenter results as compared to those of 168 patients from CSMC were not significantly different with respect to the overall sensitivities (94% versus 95%) and specificities (44% versus 56%) for identification of CAD and normalcy rates which were determined in LL patients (82% for both) and with respect to identification of individual diseased arteries. The results indicate that our method for quantifying tomographic 201TI stress scintigrams utilizing standard normal limits can be applied at other institutions by different operators, using a variety of cameras and computers, with similar accuracy to that currently obtained at our institution.

Coronary Disease↗
PubMed1990

[Hereditary epidermolysis bullosa and laryngeal involvement].

Two cases of epidermolysis bullosa (EB) with laryngeal involvement are reported in 2 Algerian girls, aged 6 and 7 years. The first one with a junctional EB, received local treatment with good results. For the second, with an EB dystrophica, tracheostomy was necessary and remained so. Laryngeal involvement is rare in EB. It and remained so can be serious and life-threatening. Eight cases where previously reported. Their clinical and therapeutical particularities are discussed.

Child↗
PubMed1989

Quantitative single photon emission computed thallium-201 tomography for detection and localization of coronary artery disease: optimization and prospective validation of a new technique.

One hundred eight-three men underwent stress-redistribution thallium-201 myocardial perfusion tomography. After evaluation of various preprocessing filters in a phantom study, the Butterworth filter with a frequency cutoff of 0.2 cycles/pixel, order 5 (which provided optimal filter power) was used in the back projection algorithm of the patient studies. All short-axis and apical portions of vertical long-axis images were quantified by dividing each myocardial slice into 60 equal sectors and displaying the maximal count per sector as a linear profile. In a pilot group consisting of 20 normal men (less than 5% likelihood of coronary artery disease) and 25 men with coronary artery disease (greater than or equal to 50% coronary stenosis by angiography), profiles representing the lowest observed value below the mean normal profiles provided the best threshold for defining normal limits. Abnormal portions of the patient profiles were plotted on a two-dimensional polar map. The polar map was divided into 102 sectors, and sectors with a probability of greater than or equal to 80% for disease of each one of the three major coronary arteries were clustered to represent specific coronary artery territories. Receiver operating characteristic curve analysis for defect size showed that the optimal threshold for defining a definite perfusion defect was 12% for the left anterior descending and left circumflex and 8% for the right coronary artery territories. These criteria were prospectively applied to an additional 92 patients with angiographic coronary artery disease, 18 patients with normal coronary arteriograms and 28 patients with less than 5% likelihood of coronary disease. Sensitivity, specificity (in patients with normal coronary arteriograms) and normalcy rate (in patients with less than 5% likelihood of coronary artery disease) for overall detection of coronary disease were 96%, 56% and 86%, respectively. Sensitivity and specificity for identification of individual diseased vessels were, respectively, 78% and 85% for the left anterior descending, 79% and 60% for the left circumflex and 81% and 71% for the right coronary artery. These results were not significantly different from those of the pilot group. An optimized quantitative method for interpretation of stress thallium-201 myocardial perfusion tomography has been developed. Prospective application of this method indicates that the technique is accurate for the overall detection of coronary artery disease and identification of disease in individual arteries.

Coronary Circulation↗
PubMed1989

"Upward creep" of the heart: a frequent source of false-positive reversible defects during thallium-201 stress-redistribution SPECT.

A new cause of artifactual 201Tl defects on single photon emission computed tomography (SPECT) termed "upward creep" of the heart is described. In 102 consecutive patients undergoing 201Tl SPECT, 30 (29%) demonstrated upward creep defined by an upward movement of the heart of greater than or equal to 2 pixels during acquisition. In 45 consecutive patients with a less than 5% likelihood of coronary artery disease, 17 (38%) had upward creep. Of these nine had reversible 201Tl defects localized to the inferior and basal inferoseptal walls, while none of the 28 without upward creep had defects. The 17 low likelihood patients with upward creep had longer exercise duration and higher peak heart rate than those without upward creep. In five additional low likelihood patients with upward creep in whom imaging was immediately repeated, the upward creep pattern disappeared on the repeated images. After we changed our test protocol to begin imaging 15 min postexercise, only five (14%) of 36 low likelihood patients tested demonstrated upward creep. Upward creep is probably related to a transient increase in mean total lung volume early following exhaustive exercise, resulting in a mean lower position of the diaphragm (and thus the heart) at the beginning of imaging. The frequency of this source of false-positive 201Tl studies can be reduced by delaying SPECT acquisition until 15 min postexercise.

Adult↗
PubMed1988

Patient motion in thallium-201 myocardial SPECT imaging. An easily identified frequent source of artifactual defect.

Because Tl-201 SPECT requires that patients remain in an awkward position for a prolonged time, patient motion is a potentially serious source of artifactual defects on tomographic reconstructions. Thus, a simple method was developed for detection and correction of motion from SPECT images using a Co-57 point source placed on the lower anterior chest, an area remaining in the camera's field of view throughout imaging. In the absence of motion, this point source inscribes a straight line on planar summation of the 32 projections over 180 degrees. Movement is detected by deviation from this line. The number of pixels of motion is used to shift images so that the resultant images of the point source are linear. The method of motion detection and correction was tested in 48 consecutive patients undergoing Tl-201 SPECT. The corrected and uncorrected images were reconstructed and long and short axis tomographic cuts were quantitatively analyzed using circumferential profiles of maximal counts with comparison to the lower limits of normal. Motion was detected in eight of 48 patients (17%). The amount of motion was 2 pixels in three patients and 1 pixel in five patients. Quantitative defect extent was less after correction in seven of eight patients, with a mean decrease of 71% in patients with 2 pixel motion and 44% in patients with 1 pixel motion. This corresponded with a definite reduction in the size of the tomographic defect by visual analysis, and closer resemblance to quantitatively analyzed planar images performed either before or after tomography in the same patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Controlled study of plasma exchange in pemphigus.

To determine the potential steroid sparing effect of plasma exchange in pemphigus we enrolled 40 patients in a multicenter randomized study. Eighteen patients were treated by prednisolone alone, 22 by prednisolone plus ten large-volume plasma exchanges over four weeks. All patients received oral prednisolone in the same initial dosage (0.5 mg/kg/d), which was increased weekly if needed. The number of cases controlled at each therapeutic step did not differ between the two groups. In eight cases, four in each group, the disease was not controlled by the highest therapeutic step of the protocol, with four deaths from sepsis in the plasma exchange group. The controlled cases needed similar cumulative prednisolone doses (5237 +/- 5512 mg in the plasma exchange group vs 4246 +/- 1601 mg in the control group). The evolution of serum pemphigus antibody was not different in the two groups. These findings suggest that plasma exchange in association with low steroid doses alone are not effective in the treatment of pemphigus and may even promote sepsis.

Adult↗