Evaluation of various corrections to the standardized uptake value for diagnosis of pulmonary malignancy.

OBJECTIVE: Standard uptake values (SUVs) are widely used for quantifying the uptake of 18F-fluorodeoxyglucose (18F-FDG) in tumours. The objective of this study was to evaluate the accuracy of SUVs for malignancy in lung nodules/masses and to analyse the effects of tumour size, blood glucose levels and different body weight corrections on SUV. METHODS: One hundred and twenty-seven patients with suspicious lung lesions imaged with 18F-FDG positron emission tomography (PET) were studied retrospectively. Pathology results were used to establish lesion diagnosis in all cases. SUVs based on maximum pixel values were obtained by placing regions of interest around the focus of abnormal 18F-FDG uptake in the lungs. The SUVs were calculated using the following normalizations: body weight (BW), lean body weight (LBW), scaled body surface area (BSA), blood glucose level (Glu) and tumour size (Tsize). Receivers operating characteristic (ROC) curves were generated to compare the accuracy of different methods of SUV calculation. RESULTS: The areas under the ROC curves for SUV(BW), SUV(BW+Glu), SUV(LBW), SUV(LBW+Glu), SUV(BSA), SUV(BSA+Glu) and SUV(BW+Tsize) were 0.915, 0.912, 0.911, 0.912, 0.916, 0.909 and 0.864, respectively. CONCLUSION: The accuracy of SUV analysis for malignancy in lung nodules/masses is not improved by correction for blood glucose or tumour size or by normalizing for body surface area or lean body weight instead of body weight.

Efficacy and safety of repeated samarium-153 lexidronam treatment in a patient with prostate cancer and metastatic bone pain.

A patient with stage D3 prostate cancer was given 11 separate doses of samarium-153 lexidronam (Sm-153 ethylenediaminetetramethylene phosphonate) of 1 mCi/kg (37 MBq/kg) in a period of 28 months for bone pain from metastases. With the first five doses, Sm-153 lexidronam clearly reduced his bone pain and improved his quality of life, as determined by pain-assessment scores and the patient's self-assessment of its effect on his ability to perform activities of daily living. With doses 6 through 11, pain at baseline was on average less, and as a result beneficial effects after treatment were not as apparent. Samarium-153 lexidronam produced transient decreases in the leukocyte and platelet counts, but these never became low enough to cause clinical concern. This case shows both the efficacy and the safety of Sm-153 lexidronam in repeated treatments for metastatic bone pain in patients with prostate cancer.

Enhanced uptake of 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone treatment: potential for increasing delivery of therapeutic agents.

Following androgen ablation therapy, skeletal metastases from prostate cancer appear in some instances to show an increase in 99Tcm-methylene diphosphonate (99Tcm-MDP) uptake. Such a phenomenon could represent a mechanism to increase delivery of bone-seeking therapeutic agents to skeletal metastatic sites. The aim of this study was to characterize more precisely the potential increase in 99Tcm-MDP in skeletal metastases from prostate cancer following initiation of hormone therapy. Baseline bone scans were performed within 1 week of onset of hormone therapy in patients with stage D2 prostate cancer followed by multiple repeat bone scans for up to 4-6 weeks. The count density within metastatic lesions was divided by the average count density from several areas of normal bone to obtain a lesion to normal bone uptake ratio (L/N) for each lesion in each scan. Altogether, 61 skeletal metastases were identified on bone scans from five subjects. Eighty-four percent (51/61) of these lesions showed an increase in 99Tcm-MDP activity relative to normal bone following initiation of hormone therapy with a mean peak increase of 39%. Thirty-nine of these 51 metastatic lesions showed maximum uptake at 3 weeks post-onset of hormone treatment. From our findings, it appears that approximately 3 weeks following initiation of hormone blockade, most skeletal metastases from prostate cancer will demonstrate significantly enhanced 99Tcm uptake relative to normal bone. Consequently, it may be possible to improve the uptake and effectiveness of therapeutic bone-seeking radiopharmaceuticals by administering these agents following hormone therapy in patients with prostate cancer metastases.

PET, CT, and MRI with Combidex for mediastinal staging in non-small cell lung carcinoma.

BACKGROUND: To determine the relative utility of positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging with Combidex (MRI-C) in the non-invasive staging of non-small cell lung cancer (NSCLC) mediastinal lymph nodes (MLN), we compared the three tests' individual performance with surgical mediastinal sampling. In contrast to prior studies, cytology was not used. METHODS: The MLN were evaluated using PET and CT in 64 NSCLC patients. MRI-C was performed in 9 of these patients. MLN with a PET standard uptake value greater than or equal to 2.5, or greater than 1 cm in the short axis by CT or lack of MRI-C signal change were considered positive for metastatic disease. All MLN were sampled and subjected to standard pathologic analysis. PET, CT, and MRI-C scans were interpreted blinded to the histopathological results. Sensitivity, specificity, and accuracy for each scan type to appropriately stage MLN was determined using pathologic results as the standard. RESULTS: Thirty patients had stage I disease, 8 stage II, 9 stage IIIA, 7 stage IIIB, and 10 stage IV. Two-hundred-and-thirty MLN were sampled. Sixteen patients had metastatic mediastinal disease. Compared to the pathological results, PET, CT, and MRI-C had a sensitivity, specificity, and accuracy of 70%, 86%, 84%; 65%, 79%, 76%; 86%, 82%, and 83%, respectively. PET and MRI-C were statistically more accurate than CT (p<0.001). In cases where PET and CT did not identify MLN involvement with NSCLC, 8% (2/25) were pathologically positive. CONCLUSIONS: PET and MRI-C are statistically more accurate than CT. However, the differences are small and may not be clinically relevant. No technique was sensitive or specific enough to change the current recommendation to perform mediastinoscopy for MLN staging in NSCLC.

Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET).

The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.

Frequency of false-positive septal defects on adenosine/201T1 images in patients with left bundle branch block.

The exercise 201T1 imaging procedure in patients with left bundle branch block (LBBB) is associated with a relatively high frequency of false-positive septal perfusion defects. We therefore initiated a study designed to determine the frequency of false-positive septal defects seen with adenosine/thallium imaging. In total, 900 adenosine/thallium cases performed at our institution for assessment of coronary artery disease were reviewed. Sixty-eight patients had LBBB on resting electrocardiogram (ECG) and sucessfully completed the imaging procedure, of whom 25 had coronary angiography. Only 6 of the 68 patients demonstrated reversible septal defects on thallium imaging. Of these 6 patients, 3 underwent coronary angiography and all of them had significant (> 70%) LAD stenosis. Therefore, at most only 4% of the patients with LBBB had a false-positive reversible septal defect. Three additional patients had fixed septal defects. Of these three patients, one underwent cardiac catheterization and was found not to have significant LAD stenosis. The results from this study suggest that adenosine/thallium imaging is associated with an acceptably low frequency of false-positive septal defects and should be used as an alternative to exercise/thallium in patients with LBBB.

Colonic localization of labeled leukocytes in critically ill patients. Scintigraphic detection of pseudomembranous colitis.

This study assesses the causes of colonic localization of labeled white blood cells (WBCs) in critically ill patients who had undergone leukocyte scintigraphy for suspected infection. Forty-two patients showed abdominal or pelvic WBC localization; 20 of these had a pattern of colonic localization, and some also showed a pattern of small bowel activity. Eight of the 20 patients had documented gastrointestinal bleeding. White blood cell scintigraphy in these eight patients showed a pattern of multifocal and/or regional bowel activity that changed in intensity and location from early (3-5-hour) to delayed (18-28-hour) images. In contrast, 5 of the 6 patients with documented pseudomembranous colitis (PMC) showed intense WBC localization involving most of the colon. In 3 of these 5 patients, early and delayed images were acquired and showed a relatively constant pattern of WBC localization. The sixth PMC patient had been treated with vancomycin before leukocyte scintigraphy and showed minimal distal small bowel activity on early images and only mild regional colonic activity on delayed images. As in the patients with gastrointestinal bleeding, the remaining six patients showed either focal or regional activity of variable intensity that changed over time. In critically ill patients, gastrointestinal bleeding and PMC accounted for 14 of the 20 patients in which labeled leukocyte scintigraphy exhibited colonic activity. A pattern of diffuse, intense colonic radiotracer activity which persists from early to delayed imaging strongly suggests the presence of PMC in this patient population.(ABSTRACT TRUNCATED AT 250 WORDS)

Utility of SPECT imaging for determination of vertebral metastases in patients with known primary tumors.

Determining the etiology of a focal lesion seen on bone scan in patients with primary tumors usually requires the use of other imaging procedures or biopsy. Single positron emission computed tomography (SPECT) with high resolution multidetector systems can localize the specific site of a vertebral lesion and in this way potentially differentiate between benign and metastatic disease. SPECT images of the lower thoracic and lumbar spine were reviewed for lesion location and intensity by two experienced interpreters. Follow-up data were adequate to ascertain the cause of 71 lesions seen on SPECT in 29 patients. Twenty-six of these lesions were not seen on planar images. Of the 71 lesions, 44 were benign and 27 metastatic. Of the 15 lesions where the pedicle was involved, 11 were found to metastatic. There were a total of 14 facet lesions, 9 of which were present in vertebra with no lesions at sites other than the facets. All 9 of these isolated facet lesions turned out to be benign. Lesion intensity did not distinguish benign from malignant disease. We conclude that SPECT imaging is useful in determining the etiology of focal lesions seen on bone scan in patients with a known primary tumor referred for evaluation of metastatic disease.

Detectability of simulated brain activation using dual radioisotope SPECT based on size and intensity of the focal hyperactivity.

RATIONALE AND OBJECTIVES: Simultaneous single-photon emission computed tomography (SPECT) neuroimaging with both technetium-99m (99mTc) hexamethylpropyleneamine oxime (HMPAO) and iodine-123 (123I) N-isopropyl-iodoamphetamine is a recently introduced method with potential for assessing activation phenomena in the brain. However, there is limited information on the accuracy of the technique for detecting focal cortical sites of neuroactivation. We determined, in vitro, what levels of activation could be detected as a function of the size of the activated region. METHODS: A Lucite brain phantom was filled with both 123I and 99mTc so as to simulate both a nonactivated state (123I) along with focal sites of activation (99mTc). Simulated activations ranged from 0 to 18% in volumes of 7, 14, 20, and 27 cm3. Imaging was performed with a triple-detector gamma camera using a 10% symmetric window at 140 keV and 10% asymmetric window around 159 keV. No correction was made for gamma cross-talk. To determine whether a simulated activation was "detected," the 99mTc: 123I count ratios in the activated regions were compared by t test with ratios in nonactivated regions of similar volume. Detection sensitivities also were calculated as the fraction of the activated 99mTc: 123I ratios that were greater than the mean + 2 standard deviations of the corresponding nonactivated ratios. RESULTS: All sites of simulated activations of 10% or greater were detected. The detection sensitivity was 100% (95% confidence interval, 90-100%) for the two largest chambers with simulated activations of 13-18%. Activations in the 3-6% range, in the same-sized chambers, were detected with a limited sensitivity (67% with a confidence interval of 45-84%). In the 14-cm3 chamber, simulated activations in the 13-18% range were detected with 90% sensitivity (confidence interval, 74-98%). In general, the detection sensitivity was greater for larger chambers and higher levels of simulated activation. CONCLUSION: We conclude that the dual-radioisotope technique using triple-detector SPECT systems and low-energy all-purpose (LEAP) collimators should be highly reliable for identifying focal brain activations above 13% that cover at least 14 cm3 of brain cortex. Smaller, less intense sites of activation will be detected with reduced frequency. These conclusions are based on our assessment of only the physical parameters involved in this methodology and other factors (e.g., the possibility that the relation between cerebral radiotracer concentration and regional cerebral blood flow) may affect the results obtained with patients.

Diagnosis of recurrent brain tumor: value of 201Tl SPECT vs 18F-fluorodeoxyglucose PET.

OBJECTIVE: This prospective study was designed to compare the sensitivity and specificity of a relatively simple examination, 201Tl chloride single-photon emission CT (SPECT), with a more complex examination, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), in patients thought to have recurrent brain tumor. Because both agents have been shown to be markers of viable tumor, we hypothesized that their sensitivity and specificity should be the same. SUBJECTS AND METHODS: Nineteen patients with evidence of recurrent tumor on CT or MR images were studied with both 201Tl SPECT and FDG PET imaging. Two patients were examined twice, so a total of 21 studies were evaluated. The 201Tl SPECT and FDG PET examinations were performed on the same day in 17 patients, and the remaining four examinations were done within 1 week of one another. Three reviewers independently interpreted each Tl SPECT and PET scan. Inappropriate regional increases in 201Tl or FDG activity were considered indicative of tumor recurrence. Sensitivity and specificity values were based on biopsy results and clinical follow-up. The final diagnosis was tumor recurrence in 16 cases and radiation necrosis in 5 cases. The relationship of scan results to survival was analyzed. RESULTS: The sensitivity and specificity of the 201Tl examination for detecting tumor recurrence were 11 (69%) of 16 and two (40%) of five, respectively; values for the FDG PET examination were 13 (81%) of 16 and 2 (40%) of 5, respectively. In patients with recurrent tumors less than 1.6 cm in size, results were false-negative in four 201Tl SPECT examinations and three FDG PET studies. All tumor lesions 1.6 cm or larger (n = 8) were detected. Agreement among the three nuclear medicine specialists was complete for each of the 201Tl SPECT scans. There was disagreement on the interpretation of five (24%) of the 21 FDG PET scans, which was resolved by consensus. Scintigraphic findings did not correlate with patients' survival times. CONCLUSION: We were unable to detect a statistically significant difference in sensitivity or specificity between the 201Tl SPECT and FDG PET scans. Both techniques were sensitive for tumor recurrence with lesions less than 1.6 cm or larger. However, given the greater availability, simplicity, and ease of interpretation and the lower cost of the 201Tl SPECT studies, this technique should be considered for detection of tumor recurrence with lesions that are demonstrated to be 1.6 cm or larger on CT or MR examinations.

Captopril-enhanced 99Tcm-MAG3 renal scintigraphy in subjects with suspected renovascular hypertension.

This pilot study was undertaken to generate preliminary data on the accuracy of captopril-enhanced renal scintigraphy with a relatively new radiopharmaceutical, 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) for detecting significant renal artery stenosis. Truth data was based either on arteriographic or outcome criteria (blood pressure response to therapy). Twenty-seven subjects with suspected renovascular hypertension were studied with baseline and captopril-enhanced 99Tcm-MAG3 renal scintigraphy and renal arteriography. Scan interpretations were expressed as a probability of a significant renal artery stenosis. Scan interpretations were compared with renal arteriographic results, renal vein renin levels, blood pressure values after renal artery repair, and blood pressure control after 4-26 months of clinical follow-up. Using > or = 50% luminal obstruction on arteriography as the reference standard for renal artery stenosis and a high probability scan representing a positive test, the test sensitivity and specificity were 33 and 97%, respectively (using high or indeterminate probability to represent a positive scan, the test sensitivity and specificity were 67 and 83%, respectively). The negative predictive value of a low probability scan for renal artery stenosis was 80%. However, including a measure of renovascular hypertension (blood pressure response to renal artery repair) as the reference standard, the accuracy of the scan improves, with the negative predictive value of a low probability scan for renovascular hypertension increasing to 97%. Scintigraphic results were also positively correlated with renal vein renin values in a statistically significant fashion (two-tailed Fisher exact test statistic = 6.43, P = 0.0219). Captopril-enhanced 99Tcm-MAG3 renal scintigraphy is a moderately accurate technique for detecting renal artery stenosis. More importantly, our preliminary findings suggest that the scintigraphic technique using 99Tcm-MAG3 appears to predict the blood pressure response to renal artery repair in subjects with suspected renovascular hypertension, thereby separating subjects with haemodynamically insignificant renal artery stenosis from those with renovascular hypertension.

Crossed cerebellar diaschisis associated with balloon test occlusion of the carotid artery.

99Tcm-hexamethylpropyleneamine oxime (99Tcm-HMPAO) single photon emission computed tomographic (SPECT) brain imaging performed in conjunction with balloon test occlusion of the carotid artery has been used to assess risk of neurologic sequelae that might follow permanent surgical ligation of the artery. The predictive value of cortical hypoperfusion during temporary carotid occlusion for adverse neurologic events has been debated in previous publications. We believe that the risk of an adverse event is greater when a reduction in cortical perfusion during balloon test occlusion is associated with crossed cerebellar diaschisis (CCD). To test our hypothesis we evaluated the results of 27 99Tcm-HMPAO SPECT brain studies obtained in association with balloon test occlusions of the carotid artery. In each case we correlated clinical outcome with the presence or absence of regional decreases in cerebral perfusion and CCD. All of the 27 patients were free of neurologic symptoms during the balloon test occlusion. Seventeen of the 27 scintigraphic studies were felt to be abnormal, showing cortical perfusion defects all on the side of the occlusion. Among these 17 patients, five demonstrated CCD. Four of these five CCD patients showed evidence for cerebral cortical ischaemia on the side of the temporary carotid occlusion either shortly after the procedure or following carotid artery sacrifice. Of the remaining 12 patients with regionally reduced cerebral perfusion and no CCD, none showed evidence for cortical ischaemia in association with balloon test occlusion, and five of these 12 patients had carotid ligation without subsequent neurologic sequelae.(ABSTRACT TRUNCATED AT 250 WORDS)

Positron emission tomographic measurement of bone marrow blood flow to the pelvis and lumbar vertebrae in young normal adults.

Ten young normal adults had pelvic and lumbar vertebral body bone marrow blood flow examined using [15O]water and positron emission tomography (PET) in a study designed to assess the feasibility and reproducibility of the PET technique for measuring marrow blood flow to various marrow regions. The procedure was well tolerated. Repeated blood flow measurements obtained from two consecutive [15O]water exams on each individual subject were highly reproducible. In addition, there was minimal variation in marrow blood flow from individual to individual and no gender differences were noted. In contrast, mean +/- SD bone marrow blood flows (expressed as milliliters per minute per 100 g) at selected anatomical sites were significantly different and were as follows: lower lumbar vertebral bodies, 17.6 +/- 3.1; most posterior and superior pelvis (conventional site of percutaneous bone marrow biopsy), 14.3 +/- 3.1; and total superior pelvis, 11.1 +/- 2.0. We conclude that PET is a relatively noninvasive, simple, and reproducible technique for measuring bone marrow blood flow. Marrow blood flow is consistent between normal young subjects, but varies significantly between different anatomic regions of the marrow.

Speech fluency in aphasia. Regional cerebral blood flow correlates of recovery using single-photon emission computed tomography.

This study investigated the relationship between diminished regional cerebral blood flow (rCBF) and the recovery of fluent speech in aphasia. Single-photon emission computed tomographic brain scans using [123I]N-isopropyl-p-iodoamphetamine were obtained from 14 nonfluent aphasic patients within 30 days of cerebral infarction. Measurements of speech fluency were acquired initially and at 3 months after infarction. Nearly all of the patients exhibited significant hypoperfusion to combinations of the anterior and posterior regions of the basal ganglion, the periventricular white matter, and the inferior frontal regions. Only the inferior frontal area was significantly associated with recovery of fluent speech. This region was hypoperfused in 4 of 5 patients with poor recovery while 8 of the 9 patients with good speech fluency recovery demonstrated normal rCBF to the inferior frontal region.

Implications of an audible third heart sound in evaluating cardiac function.

We prospectively compared auscultatory findings of third heart sounds with radionuclide ventriculographic analysis of systolic and diastolic function. Cardiac auscultation was done to detect an S3 in patients referred for radionuclide ventriculographic analysis of ventricular function. Of 49 adult men with the diagnosis of chronic, nonvalvular heart failure who were referred for the evaluation of heart failure, 22 (45%) at the time of the ventriculography had an S3 present on examination. For the entire study group, the radionuclide ventriculography-derived ejection fraction was 33% +/- 19.5 (mean +/- SD) with a range of 6% to 74%. The peak ejection rate was 2.05 +/- 1.09 end-diastolic volume per second with a range of 0.30 to 4.56. The peak filling rate was 1.97 +/- 1.07 end-diastolic volume per second with a range of 0.44 to 3.94, and the time to peak filling rate was 0.18 +/- 0.11 per second with a range of 0.05 to 0.61. The presence of an S3 was associated with a reduced ejection fraction and also with impaired diastolic function as determined by the peak filling rate. The sensitivity and specificity for the S3 in detecting abnormal systolic function (ejection fraction < 50%) were 51% and 90%, respectively, with a positive predictive value of 95% and a negative predictive value of only 32%. For an ejection fraction of less than 30%, the S3 had a sensitivity and specificity of 78% and 88%. The presence of an S3 was highly predictive of an abnormal ejection fraction. The absence of an S3, however, is not uncommon in patients with a mildly impaired ejection fraction.

Dosimetric determination of I-131 activity in the treatment of recurrent, nontoxic, multinodular goiter.

Although surgical treatment of nontoxic multinodular goiter remains the most effective therapy, I-131 is a reasonable alternative in cases where thyroidectomy is not appropriate. Selection of I-131 activity in the management of nontoxic multinodular goiter has largely been empirical. The use of dosimetric measurements in guiding I-131 therapy in the treatment of a patient with a recurrent, nontoxic, multinodular goiter is described.

A quest for the relief of atherosclerosis: potential role of intrapulmonary heparin--a hypothesis.

Recent progress in the treatment of coronary artery disease is reviewed from the standpoint of changes in lifestyle, surgical techniques to revascularize the myocardium and a variety of medical interventions. Among the medical modalities, heparin appears to have a greater potential than any other agent tested to neutralize the atherogenic process at most of its stages. This potential is supported by success in clinical trials of heparin administered by intravenous, subcutaneous, pulmonary, sublingual and topical routes. The suggested self-administration of low-dose heparin by inhalation appears to be well justified and easily adaptable to home therapy. The summarized evidence suggests the need for further clinical trials to test the use of heparin in the prophylaxis of atherosclerotic disease.

Utility of late N-isopropyl-p-(iodine-123)-iodoamphetamine brain distribution in predicting outcome following cerebral infarction.

BACKGROUND AND PURPOSE: The purpose of this study was to determine utility of late N-isopropyl-p-(iodine-123)-iodoamphetamine distribution in predicting neurological and language outcome. METHODS: We prospectively studied 29 patients with unilateral hemispheric ischemic cerebral infarction using the neuroimaging method of single-photon emission computed tomography and the above tracer. Four different imaging measures reflecting late tracer distribution or redistribution and three measures indicative of the patients' overall neurological or language outcome at 3 months were used in the data analysis. All patients had neuroimaging within 30 days of infarction, and 14 patients were imaged within 10 days of infarction. Data analysis was performed for all patients combined and then separately on the groups imaged within 10 days of and more than 10 days after infarction. RESULTS: The volume of the late image defect significantly correlated with one measure of neurological outcome in the whole group and in those imaged more than 10 days after cerebral infarction. However, these results are difficult to explain based on the present understanding of the physiology of late N-isopropyl-p-(iodine-123)-iodoamphetamine distribution. CONCLUSIONS: We feel that the pattern of late N-isopropyl-p-(iodine-123)-iodoamphetamine distribution is probably not useful as an independent predictor of neurological and language outcome.

Gastric emptying in patients with severe reflux esophagitis.

The pathogenesis of gastroesophageal reflux (GER) is not fully understood. There have been reports that delayed gastric emptying is a contributing factor in some patients. To determine whether delayed gastric emptying plays a role in the genesis of GER, we correlated gastric-emptying measures obtained by scintigraphic techniques with the degree of acid reflux assessed by esophageal pH monitoring. Ten patients, all of whom had evidence of esophageal mucosal disease and severe acid reflux, were studied. Four of the 10 patients with reflux had prolongation in the lag phase of gastric solid emptying, and one of the four showed prolonged gastric-emptying t1/2. There was no significant difference, however, in the mean gastric-emptying t1/2 between a control group and the patient group. Furthermore, there was no correlation between gastric-emptying measures and degree of acid reflux. We conclude that in this group of 10 patients with severe GER, delayed gastric emptying does not play an important role in the development of gastroesophageal reflux.