Amolak Singh

Intraoperative radiolymphoscintigraphy for detection of occult nodal metastasis in patients with head and neck squamous cell carcinoma.

OBJECTIVES: We sought to determine the feasibility and utility of intraoperative radiolymphoscintigraphy as a screening procedure for the detection of occult metastatic disease in selected cases of head and neck squamous cell carcinoma (HNSCC). METHODS: Patients with accessible primary HNSCC and no evidence of metastatic disease who were already undergoing planned surgical resection of the primary tumor and elective neck dissection met the inclusion criteria. Before resection, a handheld gamma probe was used to find the radiolabeled sentinel lymph node (SLN). The neck specimen was examined ex vivo by using the gamma probe; the SLN or SLNs were dissected free from the specimen and sent separately for histopathologic examination. RESULTS: At least one SLN was identified in all patients enrolled thus far. Four patients had microscopic carcinoma found in the SLN. Two of these had cancer only in the SLN, and two had disease both in the SLN and the remaining specimen. CONCLUSIONS: Intraoperative radiolymphoscintigraphy appears to be a feasible and promising procedure to aid the surgeon in more accurately detecting occult metastatic HNSCC.

Effect of exercise on left ventricular systolic function and reserve in morbid obesity

To assess the effect of exercise on left ventricular (LV) systolic function and reserve in morbid obesity, radionuclide left ventriculography was performed before and during supine, symptom-limited bicycle exercise in 23 patients whose body weight was greater than or equal to twice their ideal body weight. Echocardiography was performed before exercise. Resting LV ejection fraction was depressed in 13 patients and LV mass was increased in 10 patients. Exercise produced nonsignificant increases (of similar magnitude) in mean LV ejection fraction in the subgroups with normal and depressed resting LV ejection fraction. Exercise produced a significant increase in LV ejection fraction from 54 +/- 8 to 65 +/- 12% (p less than 0.005) in the subgroup with normal LV mass, but produced no significant change in LV ejection fraction in the subgroup with increased LV mass (53 +/- 10 at rest, 50 +/- 12% during exercise). Moreover, the LV exercise response (change in LV ejection fraction during exercise) in the subgroup with normal LV mass was significantly different from that in the subgroup with increased LV mass (p less than 0.005). There was a strong positive correlation between LV mass and the percent over ideal body weight (r = 0.912, p = 0.01) and a strong negative correlation between LV mass and LV exercise response (r = 0.829, p = 0.01). The results suggest that increased LV mass predisposes morbidly obese patients to impairment of LV systolic function during exercise.

Determination of Death by Neurological Criteria

Until 1968, when an ad hoc Harvard Medical School Committee published a landmark paper calling for determination of death using neurological rather than cardio-vascular criteria, death was considered to have occurred when the heart irreversibly ceased beating. Since that time, every jurisdiction in the country has come to accept through law or court decision neurological criteria to define death. The authors review the issue of death by neurological criteria in light of current guidelines and recent advances.

Transient gastroparesis associated with cutaneous herpes zoster

SummaryWe report a patient who developed delayed gastric emptying with vomiting and weight loss simultaneously with herpes zoster in the sixth right thoracic dermatome. Sequential radionuclide solid egg meal gastic emptying studies were used to document gastroparesis, the response to metoclopramide and its transient nature. We present a possible explanation for this phenomenon within the context of the known pathophysiology of varicella-zoster infection.

Hypoxic brain injury: Evaluation by single photon emission computed tomography

Single photon emission computed tomography (SPECT) with 99mTc-labeled hexamethylpropylene-amine oxime (HMPAO) was used to evaluate cerebral blood flow in 6 patients with hypoxic brain injury (HBI). The SPECT scans were compared with electroencephalograms (EEGs), magnetic resonance imaging (MRI) scans, or computer tomography (CT) scans. The findings on SPECT scans in all 6 patients supported the clinical impression of HBI. SPECT showed decreased perfusion in regions of the brain including the hippocampus, cerebellum white matter, rostral brain stem, the cortex, and occiput. MRI, CT, and EEG provided information that was often not representative of HBI. It was believed that SPECT provided more useful information in the identification of HBI. SPECT imaging with 99mTc HMPAO appears to be a valuable adjunct for evaluation and clinical diagnosis of HBI patients.

Effect of exercise and cavity size on right ventricular function in morbid obesity

To assess the effect of exercise and to determine the influence of the right ventricular (RV) internal dimension on RV systolic function in morbid obesity, M-mode and 2-dimensional echocardiography and radionuclide ventriculography were performed on 22 patients whose body weight was at least twice the ideal body weight and who had no clinical or laboratory evidence of underlying organic heart disease or pulmonary disease. RV ejection fraction was measured at rest and during peak supine bicycle exercise. RV exercise response was defined as the change in RV ejection fraction during peak exercise. There was a significant negative correlation between percent over ideal body weight and RV exercise response (r = 0.86, p less than 0.00005) and between RV internal dimension and RV exercise response (r = 0.60, p less than 0.005). There were significant positive correlations between resting RV and left ventricular (LV) ejection fraction (r = 0.56, p less than 0.01) and between RV and LV exercise response (r = 0.70, p less than 0.0005). The subgroup with a high-normal or enlarged RV internal dimension (greater than or equal to 2.0 cm, n = 10) experienced no significant change in RV ejection fraction with exercise, whereas the subgroup whose RV internal dimension was less than 2.0 (n = 12) experienced a significant increase in RV ejection fraction from 44 +/- 10% at rest to 58 +/- 11% at peak exercise (p less than 0.03). The results suggest that in morbidly obese individuals without underlying cardiopulmonary disease RV dilatation may predispose to RV systolic dysfunction and assessment of RV systolic function should optimally include evaluation of RV exercise response.

Complementary role of positron emission tomography in Merkel cell carcinoma

Merkel cell carcinoma is a rare type of neuroendocrine tumor of the skin with approximately 470 documented new cases annually in the United States. These tumors have high metastatic and recurrence rates, making them aggressive and difficult to treat. Diagnostic workup usually includes computed tomography, magnetic resonance imaging, and scintigraphy methods such as octreotide scans. More recently, positron emission tomographic scanning has been used to evaluate Merkel cell carcinomas. A case of Merkel cell carcinoma, in which positron emission tomography imaging with fluorodeoxyglucose played an important role in staging, re-staging, and identifying previously unknown distant metastatic disease, is presented in this article.

Clinical significance of rapid (accelerated) gastric emptying.

Purpose The purpose of this study was to determine the significance and frequency of rapid gastric emptying (RGE) in clinical practice and to examine its relationship to age, gender, and presenting symptoms Methods The review included 750 patients who underwent scintigraphic gastric emptying studies (GES) within the past 11 years. In 80 patients with RGE, the mean gastric emptying time (GET) in female and male patients was compared with study gender differences. Similarly, the mean GET in young and old patients was compared with study age differences. The presenting symptoms and conditions indicating GES were noted. Results RGE was found in 80 of 750 study patients (10.7%). RGE was equally common in both sexes. Younger patients (mean age, 34.3 ± 9.5 years) and older patients (mean age, 67.3 ± 11.6 years) had similar mean GETs. Most patients with RGE presented with symptoms that mimicked gastroparesis. Conclusions RGE has no relationship to age or gender. RGE may be representative of early dumping syndrome in most patients. GES help make a clear distinction between early dumping syndrome and gastroparesis, which can present with similar symptoms.

Effect of beta blockade with betaxolol on left ventricular systolic function in chronic stable angina pectoris and left ventricular dysfunction

To assess the effect of beta blockade on left ventricular (LV) performance in patients with LV dysfunction and stable angina pectoris, 18 subjects taking a placebo followed by incremental doses of the cardioselective beta-adrenergic blocking agent betaxolol (5, 10, 20, 40 and 80 mg/day) were studied. The study ended with the achievement of optimal clinical beta blockade (heart rate at rest 50 to 60 beats/min, a 20% or smaller increase in heart rate during stage 1 of symptom-limited treadmill exercise using the modified Bruce protocol). Optimal clinical beta blockade produced a decrease in mean frequency of angina, from 6.8 +/- 1.7 to 0.7 +/- 0.8 episodes per week (p less than 0.0005) and an increase in mean treadmill exercise capacity, from 3.1 +/- 1.7 to 7.7 +/- 2.8 minutes (p less than 0.0005). LV systolic function was assessed at rest and during symptom-limited exercise with radionuclide left ventriculography. Mean LV ejection fraction (EF) during therapy with placebo was 39 +/- 7% at rest and 40 +/- 8% at peak exercise. Mean LVEF during optimal clinical beta blockade was 43 +/- 11% at rest and 45 +/- 10% at peak exercise. Neither of these changes was statistically significant. No patient had clinical or radiographic signs of LV failure. The results suggest that optimal clinical beta blockade with betaxolol, in doses sufficient to significantly reduce the frequency of angina and improve exercise capacity in patients with stable angina pectoris and mild to moderate LV systolic dysfunction, does not cause significant deterioration of LV systolic function or produce LV failure.

Localization of F-18 FDG in Nocardia lung infection

F-18 FDG is the most commonly used radiotracer for PET. PET has become a very powerful tool for evaluating malignancy. However, localization of FDG is not specific for malignancy, and a number of benign conditions may accumulate FDG. The authors recently encountered a case of pulmonary nocardiosis exhibiting increased uptake of FDG on a PET scan performed to exclude pulmonary malignancy. Markedly increased FDG uptake led to a biopsy that demonstrated Nocardia infection. Localization of FDG in nocardiosis may be regarded as a false-positive case when imaging for malignancy, but can uncover a lethal condition that may otherwise go unnoticed.