The TEMPO Trial at 5 Years: Transoral Fundoplication (TIF 2.0) Is Safe, Durable, and Cost-effective

BACKGROUND

Questions remain about the therapeutic durability of transoral incisionless fundoplication (TIF). In this study, clinical outcomes were evaluated at 5 years post-TIF 2.0.

METHODS

A total of 63 chronic gastroesophageal reflux disease (GERD) sufferers with troublesome symptoms refractory to proton pump inhibitor (PPI) therapy, absent or ≤2 cm hiatal hernia, and abnormal esophageal acid exposure were randomized to the TIF group or PPI group. Following the 6-month evaluation, all patients in the PPI group elected for crossover to TIF; therefore, all 63 patients underwent TIF 2.0 with EsophyX₂ device. Primary outcome was elimination of daily troublesome regurgitation and atypical symptoms at the 5-year follow-up. Secondary outcomes were improvement in symptom scores, PPI use, reoperations, and patient health satisfaction. The cost-effectiveness of TIF 2.0 was also estimated.

RESULTS

Of 63 patients, 60 were available at 1 year, 52 at 3 years, and 44 at 5 years for evaluation. Troublesome regurgitation was eliminated in 88% of patients at 1 year, 90% at 3 years, and 86% at 5 years. Resolution of troublesome atypical symptoms was achieved in 82% of patients at 1 year, 88% at 3 years, and 80% at 5 years. No serious adverse events occurred. There were 3 reoperations by the end of the 5-year follow-up. At the 5-year follow-up, 34% of patients were on daily PPI therapy as compared with 100% of patients at screening. The total GERD Health-related quality-of-life score improved by decreasing from 22.2 to 6.8 at 5 years ( P < .001).

CONCLUSION

In this patient population, the TIF 2.0 procedure provided safe and sustained long-term elimination of troublesome GERD symptoms.

Transoral fundoplication offers durable symptom control for chronic GERD: 3-year report from the TEMPO randomized trial with a crossover arm

Background

Four randomized controlled trials have demonstrated the short-term efficacy and safety of transoral esophagogastric fundoplication (TF) performed with the EsophyX^® device in eliminating troublesome gastroesophageal reflux disease (GERD) symptoms in well-selected patient populations. The aim of this study was to assess the durability of these outcomes at 3 years post-procedure.

Methods

The TF EsophyX versus Medical PPI Open Label trial was conducted in seven US sites. Between June and August 2012, we enrolled patients with small (<2 cm) or absent hiatal hernias who suffered from troublesome GERD symptoms while on PPI therapy for at least 6 months and had abnormal esophageal acid exposure (EAE). Randomization was to TF group (n = 40) or to PPI group (n = 23). Following evaluation at 6 months, all remaining PPI patients (n = 21) elected to undergo crossover to TF. Fifty-two patients were assessed at 3 years for (1) GERD symptom resolution using three GERD-specific quality of life questionnaires, (2) healing of esophagitis using endoscopy, (3) EAE using 48-h Bravo testing, and (4) discontinuation of PPI use. Two patients who underwent revisional procedures by year 3 were included in the final analysis.

Results

At 3-year follow-up, elimination of troublesome regurgitation and all atypical symptoms was reported by 90 % (37/41) and 88 % (42/48) of patients, respectively. The mean Reflux Symptom Index score improved from 22.2 (9.2) on PPIs at screening to 4 (7.1) off PPIs 3 years post-TF, p < 0.0001. The mean total % time pH <4 improved from 10.5 (3.5) to 7.8 (5.7), p = 0.0283. Esophagitis was healed in 86 % (19/22) of patients. At the end of study, 71 % (37/52) of patients had discontinued PPI therapy. All outcome measures remained stable between 1-, 2-, and 3-year follow-ups.

Conclusion

This study demonstrates that TF can be used to achieve long-term control of chronic GERD symptoms, healing of esophagitis, and improvement in EAE.

Transoral Incisionless Fundoplication: 2-year Results from the Prospective Multicenter U.S. Study

The aim of this study was to assess prospectively 2-year outcomes of transoral incisionless fundoplication (TIF) in a multicenter setting. A 14-center U.S. registry was designed to evaluate the effects of the TIF 2.0 procedure on chronic gastroesophageal reflux disease (GERD) in over 100 patients. Primary outcome was symptom assessment. Secondary outcomes were proton pump inhibitor (PPI) use, degree of esophagitis, safety, and changes in esophageal acid exposure. One hundred twenty-seven patients underwent TIF between January 2010 and April 2011, 19 (15%) of whom were lost to follow-up. Eight patients undergoing revisional surgery were included, as failures, in the 108 remaining patients. No serious adverse events were reported. GERD Health-related Quality of Life and regurgitation scores improved by 50 per cent or greater in 63 of 96 (66%) and 62 of 88 (70%) patients who had elevated preoperative scores. The Reflux Symptom Index score normalized in 53 of 82 (65%) patients. Daily PPI use decreased from 91 to 29 per cent. In patients amenable to postoperative testing, esophagitis healed in 12 of 16 (75%) and esophageal acid exposure normalized in eight of 14 (57%). TIF safely achieved sustained symptomatic control over a 2-year period in two-thirds of patients with a virtual absence of de novo side effects.

Transoral incisionless fundoplication: 2-year results from the prospective multicenter U.S. study

The aim of this study was to assess prospectively 2-year outcomes of transoral incisionless fundoplication (TIF) in a multicenter setting. A 14-center U.S. registry was designed to evaluate the effects of the TIF 2.0 procedure on chronic gastroesophageal reflux disease (GERD) in over 100 patients. Primary outcome was symptom assessment. Secondary outcomes were proton pump inhibitor (PPI) use, degree of esophagitis, safety, and changes in esophageal acid exposure. One hundred twenty-seven patients underwent TIF between January 2010 and April 2011, 19 (15%) of whom were lost to follow-up. Eight patients undergoing revisional surgery were included, as failures, in the 108 remaining patients. No serious adverse events were reported. GERD Health-related Quality of Life and regurgitation scores improved by 50 per cent or greater in 63 of 96 (66%) and 62 of 88 (70%) patients who had elevated preoperative scores. The Reflux Symptom Index score normalized in 53 of 82 (65%) patients. Daily PPI use decreased from 91 to 29 per cent. In patients amenable to postoperative testing, esophagitis healed in 12 of 16 (75%) and esophageal acid exposure normalized in eight of 14 (57%). TIF safely achieved sustained symptomatic control over a 2-year period in two-thirds of patients with a virtual absence of de novo side effects.

Univariate and multivariate analyses of preoperative factors influencing symptomatic outcomes of transoral fundoplication

Background

Preoperative factors predicting symptomatic improvement after transoral fundoplication (TF) in chronic gastroesophageal reflux disease (GERD) patients with persistent symptoms on proton-pump inhibitors (PPIs) therapy have not been elucidated fully.

Methods

Univariate and multivariate logistic regression analyses were performed on data from 158 consecutive patients who underwent TF with the EsophyX device between January 2010 and June 2012 in 14 community centers. Variables included age, gender, body mass index, GERD duration, PPIs therapy duration, presence of hiatal hernia, esophagitis, Hill grade, quality of life scores (QOL) on PPIs, % total time pH < 4, and DeMeester score on reflux testing off PPIs.

Results

All patients suffered from typical GERD symptoms. Additionally, 78 % (124/158) of patients suffered from atypical symptoms. Six percent (10/158) with recurrent GERD symptoms refractory to PPI therapy underwent revisional procedure (9 laparoscopic Nissen, 1 TF). Median follow-up was 22 (range 10–43) months. For patients with typical symptoms, univariate analyses revealed 4 preoperative factors predictive of successful outcomes: age ≥ 50 [odds ratio (OR) = 2.4, 95 % confidence interval (CI) = 1.2–4.8, p = 0.014], GERD Health-related Quality of Life score (GERD-HRQL) ≥ 15 on PPIs (OR = 6.0, CI = 1.2–29.4, p = 0.026, Reflux Symptom Index score  > 13 on PPIs (OR = 2.4, CI = 1.1–5.2, p = 0.027), and Gastroesophageal Reflux Symptom Score  ≥ 18 on PPIs (OR = 2.6, CI = 1.2–5.8, p = 0.018). Age and GERD-HRQL score remained significant predictors by multivariate analysis. For patients with atypical symptoms, only GERD-HRQL score ≥ 15 on PPIs (OR = 9.9, CI = 0.9–4.6, p = 0.036) was associated with successful outcomes.

Conclusions

Elevated preoperative QOL scores on PPIs and age ≥ 50 were most closely associated with successful outcome of TF in patients with persistent symptoms despite medical therapy.

Transoral incisionless fundoplication effective in eliminating GERD symptoms in partial responders to proton pump inhibitor therapy at 6 months: the TEMPO Randomized Clinical Trial

BACKGROUND

Incomplete control of troublesome regurgitation and extraesophageal manifestations of chronic gastroesophageal reflux disease (GERD) is a known limitation of proton pump inhibitor (PPI) therapy. This multicenter randomized study compared the efficacy of transoral incisionless fundoplication (TIF) against PPIs in controlling these symptoms in patients with small hiatal hernias.

METHODS

Between June and August 2012, 63 patients were randomized at 7 US community hospitals. Patients in the PPI group were placed on maximum standard dose (MSD). Patients in the TIF group underwent esophagogastric fundoplication using the EsophyX2 device. Primary outcome was elimination of daily troublesome regurgitation or extraesophageal symptoms. Secondary outcomes were normalization of esophageal acid exposure (EAE), PPI usage and healing of esophagitis.

RESULTS

Of 63 randomized patients (40 TIF and 23 PPI), 3 were lost to follow-up leaving 39 TIF and 21 PPI patients for analysis. At 6-month follow-up, troublesome regurgitation was eliminated in 97% of TIF patients versus 50% of PPI patients, relative risk (RR) = 1.9, 95% confidence interval (CI) = 1.2-3.11 (P = .006). Globally, 62% of TIF patients experienced elimination of regurgitation and extraesophageal symptoms versus 5% of PPI patients, RR = 12.9, 95% CI = 1.9-88.9 (P = .009). EAE was normalized in 54% of TIF patients (off PPIs) versus 52% of PPI patients (on MSD), RR = 1.0, 95% CI = 0.6-1.7 (P = .914). Ninety percent of TIF patients were off PPIs.

CONCLUSION

At 6-month follow-up, TIF was more effective than MSD PPI therapy in eliminating troublesome regurgitation and extraesophageal symptoms of GERD.

A prospective multicenter registry of patients with chronic gastroesophageal reflux disease receiving transoral incisionless fundoplication

BACKGROUND

This study was undertaken to validate previously reported safety and symptomatic outcomes of transoral incisionless fundoplication (TIF), evaluate the relative benefit of TIF within different gastroesophageal reflux disease (GERD) subgroups, and to determine predictors of success in community settings.

STUDY DESIGN

Between January 2010 and February 2011, 100 consecutive patients who underwent TIF procedures at 10 centers were enrolled in this prospective, open-label, multicenter, single-arm study. Symptom improvement and objective outcomes of TIF were analyzed at 6-month follow-up.

RESULTS

One hundred TIF procedures were performed. No complications were reported. Median GERD symptom duration was 9 years (range 1 to 35 years) and median duration of proton pump inhibitor (PPI) use was 7 years (1 to 20 years). Maximal medical therapy resulted in incomplete symptom control for 92% of patients; GERD Health-Related Quality of Life (GERD-HRQL) total score was normalized in 73%. Median heartburn and regurgitation scores improved significantly, from 18 (range 0 to 30) and 15 (range 0 to 30) on PPIs before TIF to 3 (range 0 to 25) and 0 (range 0 to 25), respectively; p < 0.001. Median Reflux Symptom Index scores were reduced after TIF from 24 (range 14 to 41) to 7 (range 0 to 44); p < 0.001. Eighty percent of patients were completely off PPIs after TIF vs 92% of patients on PPIs before TIF. Preoperative factors associated with clinical outcomes were less severe heartburn (total GERD-HRQL ≤ 30, p = 0.02) and the presence of esophagitis (p < 0.02).

CONCLUSIONS

Transoral incisionless fundoplication is safe and effective in multiple community-based settings in the treatment of medically refractory GERD, as demonstrated by an absence of complications, excellent symptom relief, and complete cessation of PPIs at 6-month follow-up.

Transoral incisionless fundoplication offers high patient satisfaction and relief of therapy-resistant typical and atypical symptoms of GERD in community practice

This retrospective study evaluated clinical outcomes in 124 consecutive gastroesophageal reflux disease (GERD) patients who underwent transoral incisionless fundoplication (TIF) at 2 community hospitals. Out of 123 patients treated successfully, 110 gave consent (74% female, median age 60 [range 21-87] years, body mass index 27.5 [19.0-47.9]). At a median 7-month follow-up (range 5-17), typical and atypical symptom scores were normalized in 75% to 80% of patients, proton pump inhibitors (PPIs) were completely discontinued by 93%, and 83% were satisfied with their current health condition. Endoscopy in 53 patients revealed Hill grade I tight valves in 89% of the cases, reduced hiatal hernia in 33/34 (97%), and healed reflux esophagitis in 25/30 (83%). Based on global analysis, 72% of the patients were in remission, 20% improved symptomatically, and only 8% had ongoing GERD. These results supported the safety and efficacy of TIF as well as encouraged its application as an alternative treatment of GERD refractory to PPIs.

Changes in regional cerebral blood flow after electroconvulsive therapy for depression

Fifteen patients with major depression and normal results of magnetic resonance imaging or computed tomographic studies were treated by electroconvulsive therapy (ECT). The regional cerebral blood flow (rCBF) of these patients was imaged using Tc-99m hexamethylpropylene amineoxime single-photon emission computed tomography before and after treatment, and their images were compared with a population of 11 healthy volunteers. Before ECT treatment, the patients had hypoperfusion of the frontal region compared with the controls, and they had multiple areas of altered perfusion throughout the brain. Five of the patients had an excellent clinical response to ECT; these patients also showed changes toward normal in rCBF. The remaining patients had minimal to moderate clinical response and showed no significant change in rCBF. These results indicate that improvement in clinical status as a result of ECT is correlated with a change toward normal in rCBF.

Splanchnic erythrocyte content decreases during hemodialysis: a new compensatory mechanism for hypovolemia

Splanchnic and splenic erythrocyte volumes decrease during postural changes and exercise to help maintain central blood volume and cardiac output. The contribution of this compensatory mechanism to hemodynamic stability during dialysis has not been studied, however. In 8 ESRD patients, age 51.0 +/- 4.5 years old, we measured changes in the splanchnic/splenic erythrocyte volume during dialysis by tagging the patients' erythrocytes with technetium and following abdominal radioactivity over time. Splanchnic radioactivity decreased to 90.2 +/- 3.8% (mean +/- SEM) of the baseline value after 2 hr of accelerated fluid removal (3.7 +/- 0.4 liters) during dialysis (DUF), while it remained relatively unchanged after two hours of dialysis without fluid removal (DD) [106.5 +/- 2.3%, P (DUF vs. DD) = 0.03]. Splenic radioactivity decreased to 89.2 +/- 5.0% of the initial value during DUF versus 103 +/- 3.8% during DD, but the decrease was noted only during the last 30 minutes of DUF and did not attain statistical significance. Autonomic nervous system integrity was measured by the spontaneous variation of the R-R interval during deep respiration (E/I ratio) and by the Valsalva ratio. The mean E/I and Valsalva ratios in the eight patients were 1.13 +/- 0.03 (+/-SEM) and 1.42 +/- 0.1 respectively, suggesting reasonably adequate autonomic nervous system functioning. The results suggest that contraction of the splanchnic, and possibly the splenic, vascular beds occurs during fluid removal associated with hemodialysis. The resultant addition of erythrocytes to the circulation may help maintain central blood volume and cardiac output.

Delayed colonic transit in spinal cord-injured patients measured by indium-111 Amberlite scintigraphy

OBJECTIVE

Constipation is a major problem for patients with chronic spinal cord injury (SCI). However, it is not clear whether abnormal colonic transit is restricted to the rectosigmoid region or involves the entire colon. We assessed regional colonic transit with emphasis on the ascending and transverse segments in patients with chronic SCI and compared the results with those of controls using scintigraphic techniques.

METHODS

Seven patients with SCI below T1 and 10 control subjects were studied after oral ingestion of a capsule containing indium-111-labeled Amberlite (Sigma Chemical, St. Louis, MO) pellets. The capsule was coated with a pH-sensitive polymer that prevents disintegration until it reaches the ileocecal region. Assessments of the half-time of emptying and residence time of contents in ascending and transverse segments were made, as well as an assessment of the velocity of contents throughout the entire colon, including the descending colon.

RESULTS

A significantly slower half-time of emptying was found in SCI patients (ascending: 29 +/- 27 hr in SCI, 6.81 +/- 3.03 hr in controls, p < 0.01; ascending + transverse: 42 +/- 12 hr in SCI, 15.3 +/- 7.16 hr in controls, p < 0.01). The residence time of the median position of the contents was significantly prolonged in SCI patients (ascending: 31 +/- 23 hr in SCI, 8.75 +/- 4.68 hr in controls, p < 0.05; transverse: 26 +/- 3 hr in SCI, 5.0 +/- 4.4 hr in controls, p < 0.05). Overall, the velocity of the median position of contents throughout the entire colon was significantly lower in SCI (0.63 +/- 0.33 cm/hr in SCI, 2.58 +/- 1.20 cm/hr in controls, p < 0.001).

CONCLUSIONS

Patients with chronic SCI have prolonged colonic transit that involves the entire colon. Hence, treatment of constipation in these patients may need to include prokinetic agents as well as local rectal maneuvers.

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.

Evaluation of cerebral perfusion reserve using 5% CO2 and SPECT neuroperfusion imaging

Anatomic features of carotid artery stenosis, as defined angiographically, do not necessarily correlate with the hemodynamic significance of the narrowing. The concept of regional cerebral vasodilatory (or perfusion) reserve has been advocated as a means of defining the hemodynamic compromise associated with carotid lesions. We evaluated the feasibility of using SPECT imaging with 5% CO2 using I-123 IMP (N-isopropyl iodoamphetamine) or Tc-99m HMPAO (hexamethylpropylene amineoxime) to measure cerebral perfusion reserve. Imaging was performed on six asymptomatic subjects and one patient with a history of transient ischemic attacks but no evidence of carotid artery disease. A perfusion reserve index (PRI) was defined to represent the percent increase in blood flow during 5% CO2 breathing in regions supplied by the middle cerebral artery normalized for injected dose and changes in blood pressure. Significant increases in cerebral perfusion were seen in six of the seven subjects studied while breathing the 5% CO2 (P less than 0.01). The mean of the PRI values for the seven subjects was 32%, with a range of -5% to 58%. We conclude that SPECT imaging with IMP or HMPAO can be used to quantitatively measure the cerebral perfusion response to 5% CO2.

Prediction of language and neurologic recovery after cerebral infarction with SPECT imaging using N-isopropyl-p-(I 123) iodoamphetamine

Fourteen patients (10 with left-sided and 4 with right-sided cerebral infarction) were prospectively studied with single-photon emission computed tomography (SPECT) using N-isopropyl-p-(I 123) iodoamphetamine (IMP, SPECTamine) to determine its usefulness in predicting neurologic/language recovery after cerebral infarction. All neuro-SPECT imaging was performed within 30 days after infarction. Detailed assessment of neurologic and/or language recovery (after 3 months) was carried out prospectively in each patient. Patients with smaller volume IMP defects in the region of infarction demonstrated significantly better neurologic and language recovery than patients with large IMP defects. Analysis of the IMP "redistribution" phenomenon failed to demonstrate definitively a relationship with clinical recovery. It was concluded that the volume of the IMP defect can aid in predicting recovery potential after cerebral infarction.

Demonstration of focal hyperemia in acute cerebral infarction with iodine-123 iodoamphetamine

Focal hyperemia is known to occur in regions of acute cerebral infarction. Presented here are two cases in which SPECT images with 125I-labeled iodoamphetamine demonstrated focal areas of increased tracer concentration associated with cerebral infarction. These results may have important implications regarding the physiology of iodoamphetamine in cerebral infarction and, in particular, whether the distribution of this tracer is related to regional blood flow in this setting. In addition, interpretation of iodoamphetamine images in cerebral infarction should include consideration of this finding.

Functional image data acquisition and processing

In the production of functional images certain hardware and software considerations are necessary for the rapid and accurate determination of kinetic parameters. The advent of the digital scintillation camera has made available increased accuracy of quantitation and ease of image handling, although its integrated computer system may not be optimal for program development presently. To reduce the deleterious effects of Poisson noise on parameter estimation, the single or multiple application of easily implemented smoothing operators in space and time is recommended as a first step in image processing. The properties of these operators are conveniently expressed in terms of their variance. Following smoothing, count or variance thresholding is performed to reduce computer processing time and eliminate extraneous background from functional images. Time-activity curves can be fit by a variety of mathematical functions, the most useful of which is probably the finite Fourier series. In a simulated gated blood-pool study of the left ventricle, with and without an aneurysm, it is found that increased smoothing of the original image data results in more accurate parameter determinations, to the extent that small regions of dissimilar temporal behavior are not obliterated.

Effect of acute postinfusion lipemia and free fatty acids on myocardial contractility: assessment with radionuclide ventriculography

Equilibrium gated radionuclide ventriculography was used to evaluate the effect of intravenous fat-emulsion overload and excess of free fatty acids (FFA) on left ventricular ejection fraction (LVEF) in 20 patients with and without coronary artery disease (CAD). Fifteen of these patients had normal (greater than 50%) baseline LVEF and 5 had low (less than 50%) baseline LVEF. From 100 to 150 ml of 20% artificial fat emulsion (Liposyn) was infused over 20-25 min. At the end of the infusion, triglyceridemia reached 820 +/- 220 mg% and left ventricular ejection fraction decreased from baseline 62 +/- 19% (mean +/- SD) to 58 +/- 16% (P less than 0.05, paired t-test). After completion of Liposyn infusion, 5,000 U of heparin was administered intravenously and monitoring of LVEF was continued. One and one-half hours following heparin administration, plasma FFA levels reached 3.7 + 2.0 mmol/l and LVEF rose to 69 +/- 19% (P less than 0.001, paired t-test). Our data indicate that acute intravenous fat overload can suppress and high pathophysiologic levels of FFA can increase LVEF. This effect is more uniform and statistically more reliable in patients with normal LVEF. The study failed to demonstrate any significant difference in the effect of this pharmacologic intervention between patients with and without CAD.

A comparison of dobutamine infusion and supine bicycle exercise for radionuclide cardiac stress testing

We have compared the inotropic drug dobutamine to supine bicycle exercise as a means of inducing stress in radionuclide ventriculography studies. Dobutamine has the following properties, making it favorable for widespread usage: 1) ability to be given safely in a peripheral vein, 2) rapid onset, and 3) short duration of action. Each patient underwent supine bicycle progressive resistance testing of 2 minutes per stage followed 30 minutes later by dobutamine administration. Accuracy of diagnosis was 0.93 and sensitivity was 0.89 with dobutamine, while with bicycle the accuracy was 0.93 and sensitivity was 0.94. While not designed to replace supine bicycle testing, incremental infusions of dobutamine appear to be nearly equal in accuracy and sensitivity, providing a satisfactory technique for cardiac evaluation of previously excluded patients.

Radionuclide detection of blood-retinal barrier disruption in diabetes mellitus

Diabetic retinopathy is one of the leading causes of blindness in the United States today. Because early treatment of proliferative retinopathy offers the best chance for visual salvation, there is an essential need for methods of identifying eyes at high risk. Recent research has shown that subclinical leakage from retinal blood vessels is one of the earliest signs of retinopathy. The feasibility of using radionuclide techniques to quantitate blood-retinal barrier disruption is demonstrated by a study in which 23 diabetics and 7 nondiabetics were imaged with an Anger camera in the anterior Waters projection at 2 hours after the administration of Tc-99m DTPA. In the digitized images, regions of interest were placed over each orbit and over one of the cerebral hemispheres. Orbital counts were then compared to cerebral counts on a per pixel basis. Eye to brain ratios were found to be lowest for nondiabetics and highest for patients with proliferative retinopathy. Additionally, the dynamic analysis of the same radiopharmaceutical may allow investigators to further study the pathophysiology of the diabetic eye.

The use of radionuclide retinal scintigraphy for the assessment of retinopathy in diabetes mellitus

A computerized radiotracer technique for the detection of loss of retinal vascular integrity secondary to diabetes is presented. Radionuclide retinal scintigraphy with Technetium-99m DTPA was performed on 40 insulin-dependent diabetics and 10 nondiabetics. A ratio of eye to brain activity was used to eliminate errors associated with absolute counting. Ratios were found to be significantly higher in diabetics, especially those with active neovascularization. This technique may prove useful in the assessment and staging of eyes prone to retinopathy.

Time--domain analysis in gated cardiac blood pool studies

A technique is presented for producing functional images derived from equilibrium gated blood pool studies as a means of diagnosing cardiac disease. These functional images are based on characteristics associated with the time variation of the count rate (the time domain) at each point of the image matrix rather than on the Fourier transform of the time-activity curve (the frequency domain) which has gained recent attention. As examples of this method, we present images which display the statistical variance of the time-activity curve at each pixel, corrected for the expected contribution due to random statistical fluctuation, and images which display the time at which each pixel reaches its minimum count value. Variance and time-to-minimum images are comparable to Fourier amplitude and phase images, respectively, and have been found to be useful in facilitating the diagnosis of wall motion abnormalities. A major advantage of time-domain analysis is the wide variety of features of potential clinical significance which may be investigated.

Effect of chemical and radiochemical impurities from eluants on 99mTc-labeling efficiency

Occasionally, radiopharmaceuticals prepared from the eluates of 99Mo-99mTc generators that have not been eluted for several days contain large amounts of free pertechnetate, as tested by radiochromatography and biologically by administration to patients. We fing the most probable causes of poor 99mTc-labeling in these cases to be: a) the presence of a large concentration of 99TcO4-in eluants; b) insufficient stannous ions available for the complete reduction of Tc due to spontaneous oxidation of Sn in the vial and also due to oxidation of stannous ions by the presence of larger than expected concentrations of H2O2 and HO2 radicals in the eluant.

Absorbed radiation dose from radionuclidic impurities in several 123I-labeled radiopharmaceuticals

The radiation dose to patients from RISA, sodium iodohippurate, and rose bengal labeled with commercially available 123I and its accompanying radioimpurities has been studied. The extra radiation dose to target organs was found to range from 29% to 97% that due to 123I alone when the radiopharmaceutical is administered at calibration time. Additional delay in the time of administration increases the relative impurity dose.

Tc-99m labeled complexes of aldehydes and glutamate as cholescintigraphic agents

Tc-99m pyridoxylidene glutamate has proven to be an excellent biliary scanning agent, far superior in many respect to the commonly used I-131 rose bengal. The preparation of the compound as previously reported by Baker et al is too time consuming and requires the use of an autoclave which is not available in most nuclear medicine departments. In our facility, we have been preparing similar compounds using several aldehydes and monosodium glutamate to make labeled complexes having the same pharmacological characteristics. The mixture of monosodium glutamate, aldehyde, and Tc-99m pertechnetate is made slightly alkaline, purged with helium, and placed in a sealed vial. The vial, which is protected by a wire basket, is then heated in a laboratory oven at 130 degrees C for a period of 15 to 20 minutes. During this time, the technetium is reduced to a lower valence state and bound to the complex formed. Chromatographic data show that these compounds are chemically similar to that previously reported. The compounds prepared concentrate in the gall bladder of the rabbit in less than 10 minutes. Kinetic studies have been performed on dogs with a scintillation camera and small digital computer to measure rates of blood clearance, liver and gall bladder uptake, and excretion into the intestine. The aldehyde -- glutamate complex promises to be a useful scanning agent for the diagnosis of biliary and hepatocellular diseases.

Dual-channel facilitation of the 99mTc radiocardiogram

A refinement of the radionuclide-angiocardiogram is described using a low deadtime scintillation camera and hardwire data storage, processing, and display system for the purpose of anatomic definition of the passage of a radioactive bolus through the carciopulmonary circulation by dual-channel, dual-color, subtraction methodology. The summation of the bolus pathway is displayed as a static frame of reference for the sequential kinetic image. The technique is noninvasive and employs 15 mCi of 99mTc pertechnetate. This procedure may be employed as the conventional bolus study for determining the cardiac kinetics ordinarily obtained by the method. The opportunity of viewing the bolus position in relation to its entire pathway significantly facilitates defining the multiple areas of interest the observer may wish to study.