Avi Front

Gastric emptying time and gastric motility in patients with Parkinson's disease

Gastrointestinal symptoms such as nausea, abdominal pain, and bloating are frequent complaints of patients with Parkinsons disease (PD). It has been postulated that impaired gastrointestinal function may contribute to the development of motor fluctuations such as delay on and no on in patients with PD. Gastrointestinal impaired function and symptoms may be associated with the disease itself or secondary to levodopa treatment. Thus, we assessed gastric emptying (GE) and gastric motility in PD patients to examine the association between clinical status and gastric function. GE and antral contraction (frequency and amplitude) were evaluated by scintigraphy in 29 patients with mild PD (Hoehn and Yahr [H&Y] stage 1.0–2.0); 22 patients with moderate PD (H&Y stage 2.5–3.0); and 22 healthy volunteers, following the ingestion of a labeled standard meal. Gastric emptying (mean ± SD of T1/2) and antral contraction were not significantly different between patients with mild PD (63.4 ± 28.8 minutes) and moderate PD (54.7 ± 25.5 minutes). In the control group, GE was 43.4 ± 10.8 minutes (range 29.0 – 61.0 minutes). The prevalence of delayed emptying (>61 minutes) was not significantly different in patients with mild disease (48.3%) as compared with patients with moderate disease (36.4%). Antral contraction, both frequency and amplitude, were not significantly different between patients with mild and moderate PD throughout the entire 100 minutes of the study. Untreated patients (n = 28) had mean GE T1/2 of 59 ± 30.6 minutes. Patients with smooth response to levodopa showed slower GE (n = 10; 73.6 ± 25.3 minutes), while treated patients with motor response fluctuations when tested at the on state (n = 13), had much faster GE (49.3 ± 16.2 minutes). This shortened GE in the on state was similar to the GE of normal volunteers. We conclude that gastric emptying time in patients with PD was delayed compared with control volunteers. It was even slower in patients treated with levodopa. This effect of levodopa treatment was reversed to pseudonormalization (normal GE) at the advanced stages of the disease, when patients developed motor response fluctuation. Other clinical features of PD were not associated with delayed gastric emptying.

Effects of exposure to low concentrations of carbon monoxide on exercise performance and myocardial perfusion in young healthy men.

OBJECTIVE: To assess the effects of exposure to low concentrations of carbon monoxide (CO), as commonly measured in atmospheric urban air pollution and certain occupational environments, on exercise performance and myocardial perfusion in young healthy men, and the possible need for tighter restrictions on ambient concentrations of CO. METHODS: 15 young, healthy non-smoking men, 18-35 years old, were exposed blindly and randomly to air or to a mixture of CO and air, followed by an exercise treadmill test with thallium heart scintigraphy. Blood was drawn for determination of carboxyhaemoglobin before and at the end of the exposure, and for lactic and pyruvic acid at the beginning and the end of the exercise test. The main outcome measures include the duration of the exercise test, the maximal effort expressed in metabolic equivalent units (METs), the mean plasma lactic to pyruvic acid ratio at the end of the ergometry, ECG changes in the exercise test, and perfusion deficits in thallium heart scintigraphy. RESULTS: At the end of exposure to CO, the mean (SD) blood carboxyhaemoglobin concentration rose from 0.59% (0.08%) to 5.12% (0.65%) (p < 0.0001). At the end of the exercise period, the mean (SD) plasma lactate/pyruvate ratio, which reflects the level of anaerobic metabolism (69.9 (5.9) after air and 75.9 (7.0) after CO), was not significantly different between the two experimental groups. Exercise induced electrocardiographic changes were noted in only one subject after exposure to CO. No arrhythmias were detected in any of the subjects. Significant differences were found in the mean duration of the exercise test (p = 0.0012) and the METs (p = 0.0001). The mean adjusted difference of exercise duration between exposure to air and CO was 1.52 minutes 95% confidence interval (95% CI) 0.73 to 2.32 minutes. The mean adjusted difference of METs between exposure to air and CO was 2.04 95% CI 1.33 to 2.76. The models for duration of exercise and METs showed no significant sequence and period effects. Thallium myocardial perfusion imaging disclosed normal perfusion in all regions of the heart, with no significant differences in perfusion between the two exercise tests (after air or CO). CONCLUSION: Acute exposure to a low concentration of CO which produces blood carboxyhaemoglobin concentrations of 4%-6% significantly decreases exercise performance in young healthy men. No ischaemic electrocardiographic changes or disturbances in myocardial perfusion were found by graded exercise with thallium scintigraphy. Our findings suggest that pollution of atmospheric air by CO at concentrations which are commonly found in urban and industrial environments may exert an adverse effect on skeletal muscles, manifesting as decreased exercise performance.

Myocardial perfusion abnormalities early (12-24 h) after coronary stenting or balloon angioplasty: implications regarding pathophysiology and late clinical outcome.

Objective: We prospectively examined the prevalence of reversible perfusion defects on very early (12–24 h) thallium-201 single photon emission computed tomography (SPECT) scintigraphy after angiographically successful percutaneous coronary intervention (PCI) by stenting and/or stand-alone balloon angioplasty and the predictive value of these defects for late target lesion revascularization (TLR). Patients and Methods: 83 consecutive patients undergoing PCI for 88 lesions (38 balloon angioplasties, 50 stents) underwent very early (12–24 h) SPECT thallium-201 scintigraphy at rest and following administration of 0.7 mg/kg intravenous dipyridamole after PCI. Univariate and multivariate clinical, procedural and scintigraphic correlates of target lesion revascularization during long-term follow-up were examined. Results: Coronary stenting achieved a larger immediate post-PCI minimal luminal dimension (2.7 ± 0.4 vs. 2.1 ± 0.4 mm, p < 0.001) and less residual stenosis (4 ± 12 vs. 19 ± 11%, p < 0.001) than stand-alone balloon angioplasty. Nonetheless, early reversible perfusion defects were similarly present in the territory supplied by 36% of stented lesions and 32% of lesions treated by balloon angioplasty (NS). Of 81 lesions (76 patients) available for long-term clinical follow-up, TLR was performed in 11% of the stent group and 14% of the balloon angioplasty group (NS). By multivariate logistic regression analysis, diabetes mellitus was the only predictor of late TLR (p < 0.05). The type of intervention (balloon or stent) predicted neither early perfusion defects nor late TLR. Conclusions: Early 201-thallium SPECT scintigraphy was abnormal in a third of patients treated by stand-alone balloon angioplasty or by stent placement. The very early SPECT scintigraphic findings did not differentiate between balloon and stent and did not predict late TLR.

Imaging Patterns of Vascular Lesions of the Head and Neck Demonstrated by Tc-99m Labeled Red Blood Cells

The authors report on three patients with head and neck masses who demonstrated different imaging patterns on Tc-99m RBC scintigraphy, suggesting different vascular pathology of the lesions. Defining these patterns can be helpful in the diagnosis and decision making concerning the appropriate treatment of these patients.

Importance of immediate and very early postprocedural angiographic and thallium-201 single photon emission computed tomographic perfusion measurements in predicting late results after coronary intervention

We examined prospectively the hypothesis that the adequacy of initial dilatation may be a major determinant of the late result of coronary angioplasty and that a better assessment of initial dilatation can be made from a combined angiographic and perfusion study than from angiography alone. Angiographic and perfusion (thallium-201 single-photon-emission computed tomography) measurements were made very early (18 to 24 hours) after coronary angioplasty in 59 patients (67 lesions) and also immediately (37 +/- 16 minutes) after the procedures in 19 of them (23 lesions). The early measurements, singly, in combination, and as a restenosis index (restenosis index = thallium-201 ischemic score (units) - minimal luminal area (squared millimeters) were examined as predictors of the late angiographic result. At late angiography (5.5 +/- 2.2 months after angioplasty), residual stenosis was related to the immediate and very early postangioplasty minimal luminal dimension, thallium-201 ischemic score, and restenosis index, and also to day-1 loss and lesion length. The combination of a normal result in the immediate or early thallium-201 perfusion study with a large ( > or = 2 mm) angiographic luminal dimension stratified a group of patients with better long-term results after angioplasty and a lower incidence of late restenosis (p = 0.03). The findings emphasize the importance of the initial procedure as a determinant of the late result of angioplasty.

Effect of Nisoldipine on Exercise Performance in Heart Failure following Myocardial Infarction

The effects of the second generation calcium channel blocking drug nisoldipine on subjective and objective measurements of exercise performance were studied in 19 patients with moderate to severe heart failure (9 New York Heart Association functional class 2, 9 class 3 and 1 class 4) due to fixed ventricular dysfunction following myocardial infarction. Nisoldipine (10 mg 3 times daily) or placebo were administered for 8 weeks in a double-blind parallel study, assessing exercise performance by symptom-limited treadmill exercise testing using a modified Naughton protocol. Nisoldipine was well-tolerated and produced a small increase in peak estimated workload performed (6.2 +/- 2.9 to 8.2 +/- 3.0 METs, p = 0.06). The rate of perceived exertion (Borg scale) increased from 17.5 +/- 2.2 to 18.8 +/- 1.2 (p less than 0.02). The higher workload was performed at a lower peak systolic blood pressure (p = 0.03), higher peak heart rate (p = 0.06) and identical double product (NS). There was no change in resting and peak heart rate and blood pressure or in exercise performance in patients receiving placebo. Resting left ventricular ejection fraction, measured by radionuclide ventriculography, was unchanged after 8 weeks both in the placebo (21 +/- 9 to 20 +/- 9%) and nisoldipine (34 +/- 17 to 36 +/- 19%) groups.

The contribution of perfusion scintigraphy in the evaluation of children suffering from recurrent localized pneumonia.

The value of perfusion scintigraphy as a screening test for children who have suffered from several episodes of recurrent localized pneumonia was evaluated in 32 patients aged 1–15 years. Perfusion studies were carried out using macroaggregated albumin (MAA) labeled with technetium 99m. In 9 patients (28%), large lobar or multisegmental perfusion defects were demonstrated. Their final diagnoses proved to be bronchiectasis (5 patients), bronchomalacia (2 cases), agenesis of a lobe (1 subject), and lobar sequestration (1 patient). In 23 children (72%), the perfusion scintigraphic patterns were normal or diffusely nonhomogeneous. All of these patients improved clinically on a 1 to 2.9-year follow-up. We conclude that a normal perfusion scintigraphy is a useful screening test for excluding structural lung abnormalities in pediatric patients with recurrent localized pneumonia. Children showing a pattern of lobar or multisegmental perfusion defects should be further investigated to rule out structural abnormalities as an underlying cause of disease.

Gallium 67 scintigraphy in the evaluation of Gardner's syndrome

Seven patients with Gardners syndrome—familial polyposis, desmoid tumors, and extracolonic manifestations—underwent gallium 67 (67Ga) scintigraphy. Gallium 67 was taken up by all desmoid tumors and skull osteomas. Three patients were considered clinically disease‐free and scintigraphy was normal. Gallium 67 scintigraphy may be a useful adjunct in the evaluation of patients with Gardners syndrome.

Reevaluation of Routine Invasive Strategy versus Noninvasive Testing following Uncomplicated ST-Elevation Myocardial Infarction

Background and Aims: While current guidelines recommend a selective invasive approach after low-risk ST-elevation myocardial infarction (STEMI) treated by thrombolysis, based on noninvasive identification of patients with residual or inducible myocardial ischemia, in many instances physicians employ a strategy of routine angiography. The present study was undertaken to reexamine the correlation between noninvasive testing and coronary angiography in patients recovering from uncomplicated STEMI with regard to detection and management of residual infarct artery stenosis and to identify patients with multivessel (MVD) or high-risk coronary disease. Methods: We prospectively performed predischarge exercise testing (ETT) and myocardial perfusion scintigraphy (MPS) prior to routine predischarge coronary angiography in 83/276 consecutive STEMI patients, who after treatment with initial and early thrombolysis, were defined as low risk by ACC/AHA risk classification. Results: ETT was positive for myocardial ischemia in 11/43 (26%) patients with single-vessel disease (SVD) and 11/22 (50%) patients with MVD, but normal or nondiagnostic in the remainder. MPS revealed significant reversible perfusion defects in 13/40 (32%) patients with SVD and 13/22 (59%) patients with MVD. A selective strategy of ETT followed by MPS for nondiagnostic ETT missed residual infarct-related artery stenosis and/or MVD in 31/81 (38%) of the cohort. Among patients who may not otherwise have been referred for angiography, severe (≧70%) residual stenosis of the infarct-related artery was present in 56% and MVD in 16%. Conclusions: Early predischarge ETT and/or MPS had limited sensitivity for the detection of coronary disease in low-risk post-STEMI patients. The study supports a simpler strategy of routine coronary angiography in most patients after low-risk STEMI.

Solitary pericardial metastasis detected by 67Ga scintigraphy in a patient with fever of unknown origin.

Abstract67Ga scintigraphy was performed in a patient with fever of unknown origin. Left pneumonectomy had been performed two years previously for carcinoma of the lung. There were no cardiovascular or new pulmonary signs. Four weeks of in hospital investigation did not reveal the cause of the fever. 67Ga uptake was localized in the heart and subsequent autopsy demonstrated pericardial metastasis to be the cause of the prolonged fever. Fever of unknown origin is a rare presenting symptom of malignant pericardial involvement and 67Ga scintigraphy was crucial in its diagnosis.