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R Taillefer

Publications and source records attributed to R Taillefer.

87 records · Page 5Linked to original sources
PubMed1983

131I-iodocholesterol (NP-59) scintigraphy in adrenocortical diseases.

The diagnostic usefulness of adrenal imaging with 131I-iodocholesterol (NP-59) is now well established. In order to correlate histopathology with the adrenal scan the authors examine and report their experience in 37 patients with surgically proven adrenal lesions or pituitary adenomas. This series included 24 patients with Cushing's syndrome: 14 caused by benign adrenal adenoma and 10 due to bilateral pituitary-ACTH-dependent adrenocortical hyperplasia. Ten patients with primary aldosteronism were submitted to surgery which confirmed the presence of aldosterone-producing adrenal adenomas. Two women with hyperandrogenism (due to virilizing ovarian tumors) had normal adrenals but the ovarian stromal luteoma markedly concentrated the iodocholesterol while the arrhenoblastoma did not. A patient with adrenal hematoma is also included in this report. The overall histopathological correlation with the radiocholesterol scintiscan yields an accuracy in our series of 97% (36/37). The false-negative adrenal scan (also missed by other non-invasive techniques) occurred in a patient with an aldosterone-producing adrenal adenoma measuring 1.0 X 1.5 cm.

19-Iodocholesterol↗
PubMed1981

Gallium-67 imaging in pericarditis secondary to tuberculosis and histoplasmosis.

In recent years, many cases of Ga-67 uptake by the heart have been reported. One such case involved a patient with tuberculous pericarditis. Recently, a patient was referred to us for the investigation of a fever of unknown origin. A Ga-67 scan was performed and showed an intense uptake by the pericardium. The final diagnosis was pericarditis secondary to mediastinal lymph node involvement with tuberculosis and histoplasmosis.

Adolescent↗
PubMedDate not supplied

Myocardial technetium 99m-labeled sestamibi single-photon emission computed tomographic imaging in the detection of coronary artery disease: comparison between early (15 minutes) and delayed (60 minutes) imaging.

BACKGROUND: Previous studies have demonstrated that there is a "partial" myocardial redistribution of 99mTc-labeled sestamibi (MIBI) between 1 and 3 hours after intravenous injection at stress. The purpose of this prospective study was to compare MIBI single-photon emission computed tomographic (SPECT) imaging performed 15 and 60 minutes after the injection at stress in the detection of coronary artery disease. METHODS AND RESULTS: Thirty-five patients with coronary artery disease (26 underwent coronary angiography and 23 had a positive 201Tl study result) were included in this study. SPECT imaging started 15 minutes after the injection of 25 to 30 mCi MIBI at peak stress (180-degree arc, 32 angles, 25 sec/view, and high-resolution collimator). Patients underwent reimaging at 60 minutes according to the same protocol and with the same gamma camera. A rest study was obtained 75 minutes after the injection of MIBI (25 to 30 mCi) at rest, 48 hours later. Images (divided for a total of 19 segments per patient) were interpreted by two blinded observers for patient diagnosis and segmental comparison. The patient diagnosis was the same for the two protocols: normal = 3, ischemia = 27, and scar = 5. The segmental agreement (kappa = 0.90) was 632/665 (95.0%). The imaging performed at 15 minutes detected normal, ischemia, and scar in 413, 189, and 63 segments, respectively, whereas the imaging performed at 60 minutes detected 422, 180, and 63 segments, respectively (difference not significant). The early and delayed images were placed side by side for subjective comparison of the extent of the defect. Early imaging showed slightly larger defects in six patients, equal defects in 24 patients, and slightly smaller defects in five patients. Ischemic/normal wall ratios were 0.67 +/- 0.16 at 15 minutes and 0.68 +/- 0.15 at 60 minutes. CONCLUSIONS: There is no clinically significant difference between SPECT imaging performed at 15 minutes or 60 minutes after the injection of MIBI at stress. Furthermore, this study showed that it is feasible to obtain good-quality MIBI images even 15 minutes after the injection at stress.

Adult↗
PubMedDate not supplied

Northern exposure: nuclear cardiology in the Canadian health care system.

The Canadian health care system may provide valuable insights into the future practice of nuclear cardiology in the United States. Rationing of medical care is not legislated by the Canadian health care system, although resource allocation is required of Canadian physicians and hospital administrators. Canadian nuclear cardiologists and physicians are not restricted in the ordering of diagnostic studies, despite the decreased availability in imaging systems and the centralization of equipment and personnel in Canada. Canadian imaging equipment is, in general, used more with less average idle time per unit. Delays in the performance of nonemergent imaging studies are more common in Canadian imaging laboratories. The number of out-of-hospital nuclear medicine laboratories is not increasing, because of government constraints on licensing and the general requirement that only radiologists or certified nuclear medicine physicians can operate these laboratories. A survey of 71 nuclear cardiology laboratories in the United States and Canada reveal that 21% of all cardiac imaging studies are performed for post-myocardial infarction risk stratification in Canada, compared with only 11% in United States laboratories. Rest and reinjection thallium imaging studies are performed more than twice as often in the United States laboratories. Canadian laboratories perform a higher average number of myocardial perfusion (2123 vs 1789) and ventricular function (773 vs 554) studies as compared with their United States counterparts. No other significant differences in clinical usage patterns were identified. A total of 130,000 nuclear cardiologies were performed in Canada in 1993, with less than 5% growth in the number of Canadian studies projected for 1994. Forty-five percent of Canadian perfusion studies are performed with 99mTc-labeled sestamibi frequently using a 2-day protocol (60%) with electrocardiogram gating (30%). Positron emission tomography (PET) can be performed in only six Canadian cities. Canadian PET centers are government funded, located in university teaching hospitals, and principally used for the purpose of research. Stress echocardiography is not widely performed in Canada because of the heavy clinical volume of standard echocardiographic studies at most hospitals, which reduces the time available for stress echocardiography. No separate billing code is available for stress echocardiography studies in Canada. Canadian cardiologists have accepted the value of rest and stress nuclear studies for the management of their patients and have concluded that it is more time efficient to perform clinical duties in lieu of stress echocardiographic studies. In conclusion, the realities of the Canadian health care system are that universal health care is valuable as long as it is consistent high quality medical care, and that the cost of universal coverage must be borne by the taxpayer using the system. The fact that nuclear cardiology has continued to thrive in the Canadian health care system suggests that future health care modifications in the United States will not exert a significant impact on the practice of nuclear cardiology.

Canada↗
PubMedDate not supplied

Comparison between dipyridamole and adenosine as pharmacologic coronary vasodilators in detection of coronary artery disease with thallium 201 imaging.

BACKGROUND: Both dipyridamole and adenosine are widely used as pharmacologic stressors with 201Tl imaging for detection of coronary artery disease. The purpose of this study was to compare dipyridamole and adenosine 201Tl imaging directly in patients with angiographically proved coronary artery disease. METHODS AND RESULTS: Fifty-four patients were submitted to two planar 201Tl studies: one with dipyridamole and the other with adenosine. The interval between the two studies varied from 2 to 7 days and the order was assigned randomly. Three standard planar views were obtained 10 minutes and 4 hours after the injection of 3.0 mCi 201Tl. Administration of dipyridamole was as follows: 0.142 mg/kg/min during 4 minutes, followed by a slight exercise and 201Tl injection. The infusion of adenosine was as follows: 0.140 mg/kg/min during 6 minutes with injection of 201Tl after the third minute of infusion. Patients were asked to give their preference considering the number, type, severity, and duration of side effects on a scale from 0 (worst) to 5 (best). Reading was done by two experienced observers. The heart was divided into three segments per view. The change in systolic blood pressure was -12 +/- 11 mm Hg for adenosine and -5 +/- 10 mm Hg for dipyridamole (p < 0.001), and the change in heart rate was 18 +/- 10 beats/min for adenosine and 8 +/- 7 beats/min for dipyridamole (p < 0.001). With regions of interest, ischemic/normal wall ratios were determined: 0.78 +/- 0.06 for adenosine and 0.83 +/- 0.08 for dipyridamole (p < 0.001). Adenosine detected 295 normal, 170 ischemic, and 21 scar segments, whereas dipyridamole detected 326, 135, and 25 segments, respectively. Patients preferred adenosine (4.3 +/- 1.0 for adenosine vs 3.8 +/- 1.5 for dipyridamole; p < 0.04) mainly because of the short duration of side effects. CONCLUSION: This study shows that the use of adenosine with 201Tl imaging may have some advantages over dipyridamole.

Adenosine↗
PubMedDate not supplied

Comparison between the end-diastolic images and the summed images of gated 99mTc-sestamibi SPECT perfusion study in detection of coronary artery disease in women.

BACKGROUND: End-diastolic images (EDI) can be easily derived from technetium 99m-sestamibi gated single photon emission computed tomography (SPECT) perfusion study (SGS). This may reduce the effect of myocardial wall thickening during systole and potentially improve the sensitivity of radionuclide perfusion imaging, especially in patients with small hearts. METHODS: This prospective study was conducted in 53 consecutive female patients to compare the diagnostic accuracy of EDI with that of the summed images (SI) of SGS. Fifty-three patients with suspected coronary artery disease (CAD), scheduled for coronary angiography within 2 months, were evaluated with SGS. Treadmill stress testing was used in 28 patients, and dipyridamole injection was used in the remaining 25 patients. A 2-day protocol was used as follows: stress test with 25 to 30 mCi of 99mTc-sestamibi and a rest study performed at least 24 hours later with the same dose. Sixteen frames per cardiac cycle were acquired for both the rest and the stress studies. Three end-diastolic frames were used for EDI, and all the 16 frames were summed for SI. SI and EDI data reconstruction were interpreted by 3 experienced blinded observers (consensus reading) during two distinct reading sessions, one with SI alone and the second with EDI alone. The heart was divided into 17 segments. RESULTS: Coronary angiography showed > or = 50% stenoses in 1 or more major coronary arteries in 38 patients and was normal in 15 patients. The sensitivity was 73.7% (28/38) and 84.2% (32/38), respectively, for SI and EDI. Three of 4 patients with CAD not detected by SI but seen with EDI were considered to have relatively small hearts. The specificity was 86.7% (13/15) and 80.0% (12/15) for SI and EDI, respectively. On a total of 901 segments, 106 ischemic defects were detected by SI and 173 by EDI (P = .001). The segmental agreement between the two techniques was 88.6% (798/901 segments). CONCLUSION: EDI showed more ischemic defects than SI, and there was also a nonsignificant trend toward an improved sensitivity of EDI in comparison to SI in detection of coronary artery disease in women, especially in patients with small hearts. EDI may be a useful adjunct to the standard perfusion imaging with SGS in such a clinical situation.

Adult↗
PubMedDate not supplied

Combined corrections for attenuation, depth-dependent blur, and motion in cardiac SPECT: a multicenter trial.

BACKGROUND: The diagnostic accuracy of cardiac single photon emission computed tomography (SPECT) is limited by image-degrading factors, such as heart or subject motion, depth-dependent blurring caused by the collimator, and photon scatter and attenuation. We developed correction approaches for motion, depth-dependent blur, and attenuation and performed a multicenter validation. METHODS AND RESULTS: Motion was corrected both transversely and axially with a cross-correlation technique. Depth-dependent blurring was corrected by first back-projecting each projection and then applying a depth-dependent Wiener filter row by row. Attenuation was corrected with an iterative, nonuniform Chang algorithm, based on a transmission scan-generated attenuation map. We validated these approaches in 112 subjects, including 36 women (20 healthy volunteers, 8 angiographically normal patients, and 8 patients with coronary artery disease [CAD] found by means of angiography) and 76 men (23 healthy volunteers, 10 angiographically normal patients, and 43 patients with CAD found by means of angiography). Either technetium 99m or thallium 201 was used for emission; either gadolinium 153 or Tc-99m was used for transmission. Images were reconstructed and blindly interpreted with a 5-point scale for receiver operating characteristic analysis in 2 ways: motion correction plus a Butterworth filter, and combined motion and blur and attenuation corrections. The interpretation by means of consensus was for the overall presence of CAD and vascular territory. The receiver operating characteristic curves for overall presence and each of the 3 main coronary arteries were all shifted upward and to the left and had larger areas under the curve, for combined corrections compared with motion correction and Butterworth. Sensitivity/specificity for motion correction and Butterworth were 84/69, 64/71, 32/94, and 71/81 overall for the left anterior descending, the right coronary artery, and circumflex territories, respectively, compared with 88/92, 77/93, 50/97, and 74/95, respectively, for the combined corrections. CONCLUSIONS: The proposed combined corrections for motion, depth-dependent blur, and attenuation significantly improve diagnostic accuracy, when compared with motion correction alone.

Coronary Disease↗
PubMedDate not supplied

[Comparison between myocardial perfusion scintigraphy with thallium-201 and technetium-99m-Sestamibi (methoxy isobutyl isonitrile) for the detection of coronary atherosclerotic disease].

99mTc-SESTAMIBI is a new myocardial perfusion agent used in the detection of atherosclerotic coronary artery disease. In the present study, myocardial scintiscanning (on treadmill) with 99mTc-SESTAMIBI and 201-Thallium were compared, and both were compared with coronary angiography. Some 130 consecutive patients were evaluated within an interval of a few weeks with scintiscans of both 99mTc-SESTAMIBI and 201-Thallium: 82 of them were also examined by coronary angiography. Segmental analysis of the two series of scans revealed some correlation in 89.2% of the segments, while correlation of the final diagnosis showed agreement in 92% of cases. Compared to coronary angiography, sensitivity in the detection of CAD was found to be 75.8% for 201-Thallium and 72.5% for 99mTc-SESTAMIBI. The authors conclude that 99mTc-SESTAMIBI is a promising myocardial perfusion agent which displays an excellent correlation with 201-Thallium.

Adult↗