Scintigraphic Measurements Research Articles

Clinical trial: a single-centre, randomised, controlled trial of tradipitant on satiation, gastric functions, and serum drug levels in healthy volunteers.

Tradipitant, an NK1 receptor antagonist, improved symptoms in patients with gastroparesis. It is unclear whether these effects are mediated centrally (e.g., vomiting centre) or on gastric functions. As a class, NK1 antagonists may retard gastric emptying (GE) or increase fasting and postprandial gastric volumes (GV). To evaluate the effects of tradipitant relative to placebo on gastric motor functions, satiation, postprandial symptoms, and pharmacokinetics. We conducted a randomised, double-blind, placebo-controlled, single-centre study of tradipitant 85 mg or matching placebo b.i.d. for 9 consecutive days in 24 healthy volunteers. During the last 2 days of treatment, participants underwent scintigraphic measurements of GE of 320 kcal egg meal, fasting and postprandial GV by SPECT, and satiation by nutrient drink ingested to maximum tolerated volume (MTV) and symptoms 30 min later. Treatments were compared by Wilcoxon rank sum test. The study had 80% power to detect group differences of 23.6% in GV and 29.2% in GE T1/2 . The two groups of healthy participants were well balanced based on demographic features, age, and BMI. There were nonsignificant positive correlations between blood levels of tradipitant and accommodation GV and GE at 4h. There were no significant effects of tradipitant, 85 mg b.i.d. for 9 days compared to placebo on GE, GV, satiation, or symptoms 30 min after MTV. Tradipitant, 85 mg b.i.d., does not significantly affect gastric motor functions (GV or GE). Importantly, there was no retardation of GE by tradipitant, which is important in relation to its potential use in patients with gastroparesis. ClinicalTrials.gov #NCT04849559.

New Drugs on the Horizon for Functional and Motility Gastrointestinal Disorders

New Drugs on the Horizon for Functional and Motility Gastrointestinal Disorders

Effects of Standard vs Energy-Dense Formulae on Gastric Retention, Energy Delivery, and Glycemia in Critically Ill Patients.

Energy-dense formulae are often provided to critically ill patients with enteral feed intolerance with the aim of increasing energy delivery, yet the effect on gastric emptying is unknown. The rate of gastric emptying of a standard compared with an energy-dense formula was quantified in critically ill patients. Mechanically ventilated adults were randomized to receive radiolabeled intragastric infusions of 200 mL standard (1 kcal/mL) or 100 mL energy-dense (2 kcal/mL) enteral formulae on consecutive days in this noninferiority, blinded, crossover trial. The primary outcome was scintigraphic measurement of gastric retention (percentage at 120 minutes). Other measures included area under the curve (AUC) for gastric retention and intestinal energy delivery (calculated from gastric retention of formulae over time), blood glucose (peak and AUC), and intestinal glucose absorption (using 3-O-methyl-D-gluco-pyranose [3-OMG] concentrations). Comparisons were undertaken using paired mixed-effects models. Data presented are mean ± SE. Eighteen patients were studied (male/female, 14:4; age, 55.2 ± 5.3 years). Gastric retention at 120 minutes was greater with the energy-dense formula (standard, 17.0 ± 5.9 vs energy-dense, 32.5 ± 7.1; difference, 12.7% [90% confidence interval, 0.8%-30.1%]). Energy delivery (AUC120 , 13,038 ± 1119 vs 9763 ± 1346 kcal/120 minutes; P = 0.057), glucose control (peak glucose, 10.1 ± 0.3 vs 9.7 ± 0.3 mmol/L, P = 0.362; and glucose AUC120 8.7 ± 0.3 vs 8.5 ± 0.3 mmol/L.120 minutes, P = 0.661), and absorption (3-OMG AUC120 , 38.5 ± 4.0 vs 35.7 ± 4.0 mmol/L.120 minutes; P = .508) were not improved with the energy-dense formula. In critical illness, administration of an energy-dense formula does not reduce gastric retention, increase energy delivery to the small intestine, or improve glucose absorption or glucose control; instead, there is a signal for delayed gastric emptying.

On the Validation of Generational Lung Deposition Computer Models Using Planar Scintigraphic Images: The Case of Mimetikos Preludium.

Background: Mechanistic computer models for calculation of total and regional deposition of aerosols in the lungs are important tools for predicting or understanding clinical studies and for facilitating development of pharmaceutical inhalation products. Validation of such models must be indirect since generational in vivo data are lacking. Planar scintigraphy is probably the most common method addressing regional lung deposition in humans. Scintigraphic regions of interest (ROI) contain mixtures of airway generations and can therefore not be directly compared to model results. We propose a method to translate computed deposition per generation to deposition in scintigraphic ROI to be able to compare computed results with corresponding results obtained in humans. Methods: The total and regional lung deposition computed by the one-dimensional algebraic typical-path software Mimetikos Preludium was compared for 18 study legs in 14 published deposition studies involving 9 dry powder inhaler brands to the activity in planar scintigraphic ROIs (oropharyngeal, central [C], intermediate, and peripheral [P]) using for the computed regional lung distribution a generic mapping of the contribution of each airway generation to the ROIs. Results: The computed oropharyngeal and total lung deposition correlated with high significance (p < 0.0001) to the scintigraphic results with a near one-to-one relationship. For the regional lung distribution, computed C, P, and P/C results correlated with high significance (p < 0.01) to the corresponding scintigraphic measures. The computed C (P) deposition was on average about 28% lower (8% higher) than the mean scintigraphic results. The computed P/C ratio was on average 29% higher than the mean scintigraphic ratio. Conclusions: The results indicate that both the computational deposition model and the mapping algorithm are valid. The small underprediction of the C region merits further investigations. We believe that this method may prove useful also for the validation of computational fluid particle dynamic lung deposition models.

Correlation of positron emission tomography ventilation-perfusion matching with CT densitometry in severe emphysema

BackgroundEmphysema severity is frequently measured on CT via densitometry. Correlation with scintigraphic and spirometric functional measures of ventilation or perfusion varies widely, and no prior study has evaluated correlation between densitometry and lobar ventilation/perfusion in patients with severe emphysema. The aim of this study was to evaluate the utility and findings of gallium-68 (68Ga) ventilation/perfusion positron emission tomography-CT (68Ga-VQ/PET-CT) in severe emphysema assessment.MethodsFourteen consecutive patients undergoing evaluation for bronchoscopic lung volume reduction between March 2015 and March 2018 underwent 68Ga-VQ/PET-CT assessment for lobar functional lung mapping, in addition to CT densitometry. Correlations between CT densitometry and 68Ga-VQ/PET-CT parameters for individual lobar lung function were sought.ResultsCT densitometry assessment of emphysema correlated only weakly (R2 = 0.13) with lobar perfusion and was not correlated with ventilation (R2 = 0.04). Densitometry was moderately (R2 = 0.67) correlated with V/Q units in upper lobes, though poorly reflected physiological function in lower lobes (R2 = 0.19). Emphysema severity, as measured by CT densitometry, was moderately correlated with proportion of normal V/Q units and matched V/Q defects in individual lobes.ConclusionsAssessment of lobar pulmonary function by 68Ga-VQ/PET-CT provides physiologic information not evident on CT densitometry such as ventilation and perfusion specifics and matched defects. Further research is needed to see if the discordant findings on 68Ga-VQ/PET-CT provide prognostic information or can be used to modify patient management and improve outcomes.

Transarterial Radioembolization with Yttrium-90 Glass Microspheres: Distribution of Residual Activity and Flow Dynamics during Administration

PurposeTo evaluate the microsphere flow dynamics and residual yttrium-90 (90Y) activity during and after transarterial radioembolization with glass microspheres and to assess the distribution and predilection sites of residual activity in the administration devices. Materials and MethodsIn this laboratory investigation, after 18 consecutive clinical transarterial radioembolization and 4 ex vivo experimental procedures with 90Y glass microspheres, the distribution of residual activity in the administration devices was assessed by activimeter and positron emission tomography (PET)/CT measurements. During ex vivo procedures, microsphere outflow from the administration device was assessed by dynamic scintigraphic measurements. ResultsMean residual activity was 3.4% ± 1.7 (range, 0.9%–8.8%). Calculations showed a negative correlation between relative residual activity and prescribed activity (r = −0.4258, P = .0486) and a positive correlation between absolute residual activity and prescribed activity (r = 0.5345, P = .0104). The main predilection site was the Luer-Lok microcatheter connector. Lower activities were detected in the dose vial. Flow measurements showed that more than 98% of the final injected activity was transferred to the patient with the first 20 mL of saline solution. ConclusionsResidual activity in the standard administration device for glass microsphere radioembolization is considered to be low compared with similar procedures, but is variable. The microsphere flow profile shows an initial peak, resulting in a rapid activity transfer at the beginning of the injection process. The findings may have implications for safe handling of the administration device and for dose calculation of 90Y glass microspheres.

Effect of Botulinum Toxin-A Injected to Muscle Tissue on Perfusion and Survival of Fasciocutaneous Single Perforator-pedicled Propeller Flap in Rats

Background:In plastic surgery practice, fasciocutaneous single-perforator-pedicled propeller flap is a preferred procedure; however, its survival rate is below than expected, especially in flaps with a big rotation arc. When botulinum toxin-A is injected into the muscle tissue that the perforator pedicle is arisen, the tonus of pertinent muscle can reduce and the blood flow of its perforator pedicle can increase. Therefore this procedure can improve the survival rate of single-perforator-pedicled propeller flap.Aims:To evaluate the effect of botulinum toxin-A injected with ultrasonographic guidance into the muscle tissue that the perforator pedicle is arisen from one month ago on the perfusion of flap scintigraphically and the survival rate of single-perforator-pedicled propeller flap in a rat model.Study Design:Animal experiment.Methods:Three study groups were receiving botulinum toxin-A (16 IU-0.4 mL), normal saline (0.4 mL), and no study drug one month ago before flap surgery. Injections were performed under ultrasonography guidance. Flaps were elevated fasciocutaneously over the right 2nd perforator pedicle, under the corneous, with a surgical loupe and microsurgery tool and were rotated clockwise 180°. Then the scintigraphic measurements were obtained after flap elevations in the study groups, including the whole-body and flap perfusions in the study rats. The involvement rate presents the ratio of flap perfusion to whole-body perfusion. Flaps were sutured back to the abdominal wall at the latest twisting angles. With standard photographs taken in all the groups on day 8 after the operation, whole and necrotic flap areas were calculated.Results:Scintigraphically the involvement rate (the ratio of flap perfusion to whole-body perfusion) of the flaps in the botulinum toxin-A group were found significantly higher than those in the other groups (p<0.05). The area of a flap in the botulinum toxin-A group on day 8 post flap suturing was found to be significantly higher than those in the other groups (p<0.05). The area of a necrosis and the percentage of necrosis on day 8 post flap suturing in the botulinum toxin-A group was found significantly lower than those of the sham and null groups (p<0.05).Conclusion:In a rat model, if with the ultrasonographic guidance, botulinum toxin-A is injected to the muscle which perforator of the prospective single-perforator-pedicled propeller flap originated and flap surgery is performed one month later after this injection, the perfusion of single-perforator-pedicled propeller flap increases scintigraphically and this improves flap survival and reduces its necrosis.

Predictor of slower gastric emptying in gastroesophageal reflux disease: Survey of an Asian-Pacific cohort.

Asian populations have relatively lower prevalence of gastroesophageal reflux disease and tend to exhibit symptoms of prolonged gastric retention. However, it remains unknown if slower gastric emptying influences its features in Asian countries. We prospectively assessed the potential implications of slower gastric emptying in an Asian-Pacific cohort of gastroesophageal reflux disease by a hospital-based survey. One hundred fifty-two patients of gastroesophageal reflux disease complete the scintigraphic measurement of solid phase of gastric emptying. Clinical symptoms and psychological stress are recorded by self-report questionnaire. The status of Helicobacter pylori infection, blood level of pepsinogen I, and I/II ratio are assessed. Forty-seven percent and 28% of the patients have slower gastric emptying rate, depending on the incremental defined cut-off values of slower gastric emptying, respectively. Multiple logistic regression analysis indicates that older age and depression score are independently related to slower gastric emptying. Subgroup analysis discloses that patients with slower gastric emptying and higher depression score tend to present with non-erosive esophagitis whereas higher body mass index level and male gender in patients with normal gastric emptying predict the presence of erosive reflux disease. Our study cohort of Asian patients indicates distinctive clinical implications of slower gastric emptying in patients with gastroesophageal reflux disease.

Validation of Ultrasonography for Assessment of Gastric Emptying Time in Healthy Cats by Radionuclide Scintigraphy.

BackgroundThe prevalence of gastric emptying (GE) disorders in cats is unknown due to lack of clinically applicable diagnostic tests.ObjectivesThe principal aim of this study was to assess correlation between scintigraphic and ultrasonographic measurements of GE time (GET) in healthy cats. Additionally, variability of ultrasonographic GET, and correlation between scintigraphy and ultrasonographic parameters of gastric motility were evaluated.AnimalsEight healthy domestic shorthair cats.MethodsProspective study. Scintigraphic GET was determined using a solid test meal containing 4 mCi 99mTc‐mebrofenin. Each cat had 3 separate ultrasonographic assessments of GE, performed independent of scintigraphic assessment, after solid test meal consumption. The motility index (MI) of antral contractions was plotted against time and time for each fraction of the area under the MI curve determined. Ultrasonographic GET and MI were correlated to scintigraphic GET.ResultsScintigraphic GET (mean ± SD) for 25, 50, and 75% GE was 103 ± 32 minutes, 196 ± 45 minutes, and 288 ± 62 minutes, whereas sonographic GET for 25, 50, and 75% GE was 106 ± 13 minutes, 203 ± 19 minutes, and 305 ± 27 minutes. There was good correlation between scintigraphic and sonographic GET (r = 0.72–0.82) at 45–90% fractional GE and between scintigraphic GET and time of corresponding MI curve fraction (r = 0.78–0.86) at 40–90% fraction of the MI curve. There was moderate intraindividual variability for sonographic GET and MI curve fraction times as well as significant variation among individuals.Conclusions and clinical importanceUltrasonography is a valid alternative to scintigraphy for assessment of solid‐phase GE and allows assessment of postprandial gastric motility in healthy cats.

A single-center, prospective, double-blind, sham-controlled, randomized study of the effect of a vibrating capsule on colonic transit in patients with chronic constipation.

In an open-label study of 26 patients with IBS-C and chronic constipation, treatment with a vibrating (VIBRANT) capsule twice a week for 7.5weeks resulted in 88.5% responders. Effects on colonic transit are unclear. We aimed to compare effects of VIBRANT and sham capsule treatment on colonic transit in patients with functional constipation. Patients with functional constipation (Rome III criteria) were randomized to VIBRANT or sham capsule treatment for 8weeks and underwent scintigraphic colonic transit measurements during week 8. We estimated the overall rate of colonic transit from the slope of progression of colonic geometric center over 48hours. The capsule was activated 8hours after ingestion, and the vibration sequence included 240 cycles. There were no significant group differences in overall colonic transit [GC48, 2.76 (IQR 2.42-4.03) for sham group and 3.46 (2.55-4.61) for active treatment group (P=.13)]. Additionally, the progression of the isotope through the colon was numerically faster, though not significantly different (slope, P=.14) in the VIBRANT capsule group compared to the sham group. Three participants in the VIBRANT capsule group had accelerated colonic transit at 32hours and faster colonic transit slope compared to the 95th percentile of the sham group. Although there were no group differences between VIBRANT and sham capsule treatment on colonic transit, at least one (and possibly three) of 12 patients receiving the VIBRANT capsule had faster colonic transit. The vibration parameters to accelerate colonic transit in patients with functional constipation require further optimization.

EVALUATION OF THYROID TO BACKGROUND RATIOS AND COMPARISON OF VARIOUS SCINTIGRAPHIC MEASUREMENTS AND THEIR CORRELATION TO SERUM T4 IN HYPERTHYROID CATS.

Thyroid-to-salivary ratio and percent dose uptake are the most widely recognized scintigraphic measurements. Recently, the thyroid-to-background ratio has been proposed as an alternate method. However, this method has not been validated. The purpose of this observational, cross-sectional, prospective study was to determine the location of a background region of interest (ROI) that is most reflective of blood pool activity. We also hypothesized that the thyroid-to-background ratio using this background ROI would be a better predictor of thyroid function. Fifty-six cats presented to the Virginia-Maryland College of Veterinary Medicine seeking radioiodine therapy for hyperthyroidism were enrolled in this cross-sectional study to evaluating thyroid-to-background ratio. A blood sample for measuring plasma radioactivity was collected at the time of scintigraphy. The plasma radioactivity was compared to the background ROIs in eight anatomic regions. Scintigraphic measures of thyroid-to-background and thyroid-to-salivary ratios, and percent dose were then compared to serum T4 . The heart ROI was most closely correlated with plasma pertechnetate activity (r = 0.70). Percent dose uptake was most closely correlated with serum T4 (r = 0.74), followed by thyroid-to-salivary ratio (r = 0.66) and thyroid-to-background ratio using the heart ROI (r = 0.59). Thyroid-to-background ratio using the heart background ROI is a good predictor T4 but percent dose uptake and thyroid-to-salivary ratio proved to be better predictors of T4 than any of the thyroid-to-background ratios.

The use of SmartPill for gastric monitoring

Testing to define delayed gastric emptying is required to diagnose gastroparesis; rapid emptying is found in other patients. Commonly performed methods of gastric emptying testing include scintigraphy and breath testing. The SmartPill wireless motility capsule (WMC) system is US FDA-approved for evaluating suspected delayed emptying in gastroparesis and functional dyspepsia. The device measures transit in the stomach, small intestine, and colon by detecting characteristic pH transitions; and quantifies pressure waves in each gut region. WMC gastric emptying times correlate with scintigraphic measures. Incremental benefits of WMC testing in patients with suspected gastroparesis include delineation of pressure abnormalities and small intestinal and colonic transit delays. Acceptance of trial data confirming usefulness of WMC testing in suspected gastric motor disorders has been hampered by small sample sizes and design limitations. Ongoing multicenter studies will validate the utility of WMC methods in patients with suspected gastroparesis and other upper gastrointestinal motor disorders.

A study of the methodological and clinical validity of the combined lactulose hydrogen breath test with scintigraphic oro‐cecal transit test for diagnosing small intestinal bacterial overgrowth in IBS patients

Small intestinal bacterial overgrowth (SIBO) may be a cause of irritable bowel syndrome (IBS); however, current investigations have important limitations. We aimed to identify clinically relevant diagnostic criteria for SIBO based on lactulose hydrogen breath test (LHBT) alone and combined with scintigraphic measurement of oro-cecal transit (SOCT). Results of LHBT/SOCT investigation from 89 IBS patients and 13 healthy volunteers were included in a systematic analysis of six published criteria for SIBO diagnosis. Clinical relevance of competing criteria was determined by assessing (i) prevalence of SIBO in IBS patients and healthy volunteers (ii) if SIBO diagnosis predicted improvement in IBS symptoms in a prospective, pilot therapeutic trial of a non-absorbable antibiotic (rifaximin 600mg b.d.) in IBS patients. Reproducibility of SIBO diagnosis by combined LHBT/SOCT was near perfect. A ≥5ppm H2 increase prior to appearance of cecal contrast was detected in more IBS patients than healthy volunteers (35/89 vs 1/13; p=0.026), but not for other diagnostic criteria. IBS patients with SIBO, compared to those without SIBO, reported significantly greater improvement in abdominal symptoms following rifaximin therapy (p<0.002 overall IBS symptom severity). This improvement was most marked in D-IBS patients in whom all symptoms improved, including stool frequency and consistency (all p<0.004). Combined LHBT/SOCT testing using a H2 5ppm cutoff may identify a subgroup of IBS patients with SIBO. Pilot data examining the clinical response to rifaximin suggest that this subset of IBS patients may benefit more than those with a normal test.

Sentinel lymph node mapping in patients with operable non-small cell lung cancer.

The aim of this study was to determine the accuracy and the role of the sentinel lymph node (SLN) in patients with non-small cell lung cancer. This study was carried out on 25 consecutive patients [M/F=23(:)2, mean age 62.84 (47-81) years] with operable non-small cell lung cancer (NSCLC). At thoracotomy, 0.25 mCi of Technecium(99m) (99mTc) nanocolloid was injected into each quadrant of lung tissue surrounding the tumor. Before resection scintigraphic measurements of lymph nodes were obtained in vivo and ex vivo using a hand-held gamma probe counter and the findings were compared with histological examination. SLN was defined as the node with the highest count rate. SLNs were identified in 23 of 25 patients (92%) with a total number of 52 SLNs. Seven of 52 (13%) of these SLNs were positive for metastatic involvement after histological and immunohistochemical examination. In two patients (8%), SLNs could not be found. The sensitivity and specificity were 55% and 86% respectively. This technic is a good method for identifying the first site of potential nodal metastases of NSCLC. These preliminary results demonstrate this procedure is feasible, but the detection rate has to be improved.

Gastric emptying measurement of liquid nutrients using the 13C-octanoate breath test in critically ill patients: a comparison with scintigraphy

Scintigraphy is considered the most accurate technique for the measurement of gastric emptying (GE) but, for patients in the intensive care unit, it is technically demanding, involves radiation and can interfere with care. The (13)C-octanoate breath test ((13)C-OBT) is a simple, non-invasive technique that does not involve radiation exposure. To evaluate the performance of the (13)C-OBT in the assessment of GE in critically ill patients. The GE was assessed in 33 mechanically ventilated patients (23M; 54.3±3.0yrs; APACHE II: 22.0±1.1). Following test meal administration (100ml Ensure(®)), concurrent scintigraphic measurement and breath samples ((13)C-OBT) were collected over 4h. Scintigraphic meal retention was determined and the gastric emptying coefficient (GEC) and half emptying time [t50(BT)] were calculated for the (13)C-OBT. Delayed GE was defined as meal retention >13% at 180min. Delayed GE was identified in 27/33 patients. Meal retention correlated modestly with t50(BT) (r=0.55-0.66; P<0.001) and well with GEC (r=-0.63 to -0.74; P<0.0001). The strength of agreement between the two techniques was highest between GEC and retention at 120min. The best cut-off GEC for defining delayed GE was 3.25 (AUC=0.75; 95% CI=0.52-0.99; P=0.05), with 89% sensitivity and 67% specificity to detect delayed GE. The GE was delayed in all (23/23) patients with feed intolerance (GRV > 250ml) on scintigraphy and 91% (21/23) patients on (13)C-OBT. In critical illness, there was a correlation between (13)C-OBT and gastric scintigraphy, with GEC performing as a better and more sensitive marker of detecting delayed GE than t50. However the relatively wide 95% confidence intervals suggest that (13)C-OBT is more suitable as a technique to assess GE in a group setting for research studies rather than for individual patients in clinical practice.

Performance characteristics of scintigraphic measurement of gastric emptying of solids in healthy participants

Gastric emptying (GE) is measured in pharmacodynamic and diagnostic studies. Our aim was to assess inter- and intra-subject coefficients of variation (COV) of scintigraphic GE measurements in healthy subjects, and associations of GE with gender and body mass index (BMI). Data from participants with scintigraphic measurements of gastric emptying of solids were analyzed. Primary endpoints were gastric emptying T(1/2) (GE T(1/2) ) and GE at 1, 2, 3, and 4 h. The patient cohort consisted of 105 males and 214 females; at least two studies were performed in 47 subjects [16 males (M), 32 females (F)]. Inter-subject COV (COV(inter) ) for GE T(1/2) were similar in M and F: overall 24.5% (M 26.0%, F 22.5%); COV are predictably lowest for GE at 4 h (COV(inter) 9.6%). COV(intra) for T(1/2) and GE at 4 h were overall 23.8% and 12.6%, and were similar to COV(inter) values. Gender (but not age or BMI) was significantly associated with GE T1/2 [P < 0.001, F 127.6 ± 28.7 (SD) min; M 109.9 ± 28.6 min] and with GE at 1 h and 2 h. Repeat GE T(1/2) values in 47 participants were significantly correlated (r = 0.459, P < 0.001) with median difference of -6 min (mean -1.6, range -56 to 72 min). Bland-Altman plots showed Δ GE T(1/2) similarly distributed across mean GE T(1/2) 100-155 min, and across studies conducted 90-600 days apart. Inter-subject variations in scintigraphic GE results are only slightly higher than the intra-subject measurements, which are also reproducible over time in healthy volunteers. Gender, but not BMI, is significantly associated with GE results.

Could Carbon Breath Test Measurement Accurately Reflect Gastric Emptying of Liquid Nutrient Meal in the Critically Ill Patients? (Gut 2011;60:1336-1343)

It is assumed that delayed gastric emptying (GE) occurs frequently in critically ill patents, but the overall prevalence of delayed GE in these patients using scintigraphy remains uncertain. Recently Chapman et al1 reported that GE was demonstrated to be slow in about 50% of intensive care unit patient using scintigraphy and the breath test appears to be an accurate alternative to scintigraphy for the measurement of GE in critically ill patients. Studies were performed in the 25 unselected, mechanically ventilated patients and 14 healthy controls. A nasogastric (NG) tube was inserted to all of healthy controls for the purpose of the study and its position was verified by pH measurement of NG tube aspirates. Prior to the study, the gastric contents were aspirated and a test meal which consisted of 100 mL Ensure (1 kcal/mL) doped with 20 MBq 99mTechnetium sulphur colloid and 75 KBq octanoic acid, [1-14C] sodium salt was infused into the stomach via the NG tube over 5 minutes. The scintigraphic measurement of GE was performed in patients and healthy controls using a mobile γ camera with 3 minute dynamic frame acquisition. Gastric meal retention (scintigraphy) at 60, 120, 180 and 240 minutes, breath test t50 (BT50) and GE coefficient were determined. Before and after the study, the gastric residual volume (GRV) was determined every 6 hour and the total volumes were documented for 24 hour preceding the study. The authors demonstrated that, of the 24 patients with scintigraphy data, GE was delayed at 120 minutes in about 50% of intensive care unit patients. Patients with delayed GE had greater severity of illness on admission to the intensive care unit, and were more likely to have been admitted with trauma, sepsis and respiratory failure. Breath tests correlated well with scintigraphy in both patients and healthy controls (% retention at 120 minutes vs BTt50; r2 = 0.57 healthy; r2 = 0.56 patients; P ≤ 0.002 for both). There was also a strong correlation between breath measurements and intragastric retention in both patients and healthy controls. In patients with slow GE there was a trend for a reduced volume nutrient delivery, and energy delivery was reduced in the patients with slow GE (normal GE 1,920 vs slow GE 510 kcal; P = 0.047). Therefore, they concluded that GE was delayed in about half of critically ill patients and markedly delayed in about 20%, and breath tests correlated well with scintigraphy and could be used as a valid method for the measurement of GE in these patients for research purposes to quantify the effects of promotility agents.

Monte Carlo verification of polymer gel dosimetry applied to radionuclide therapy: a phantom study

This study evaluates the dosimetric performance of the polymer gel dosimeter ‘Methacrylic and Ascorbic acid in Gelatin, initiated by Copper’ and its suitability for quality assurance and analysis of I-131-targeted radionuclide therapy dosimetry. Four batches of gel were manufactured in-house and sets of calibration vials and phantoms were created containing different concentrations of I-131-doped gel. Multiple dose measurements were made up to 700 h post preparation and compared to equivalent Monte Carlo simulations. In addition to uniformly filled phantoms the cross-dose distribution from a hot insert to a surrounding phantom was measured. In this example comparisons were made with both Monte Carlo and a clinical scintigraphic dosimetry method. Dose-response curves generated from the calibration data followed a sigmoid function. The gels appeared to be stable over many weeks of internal irradiation with a delay in gel response observed at 29 h post preparation. This was attributed to chemical inhibitors and slow reaction rates of long-chain radical species. For this reason, phantom measurements were only made after 190 h of irradiation. For uniformly filled phantoms of I-131 the accuracy of dose measurements agreed to within 10% when compared to Monte Carlo simulations. A radial cross-dose distribution measured using the gel dosimeter compared well to that calculated with Monte Carlo. Small inhomogeneities were observed in the dosimeter attributed to non-uniform mixing of monomer during preparation. However, they were not detrimental to this study where the quantitative accuracy and spatial resolution of polymer gel dosimetry were far superior to that calculated using scintigraphy. The difference between Monte Carlo and gel measurements was of the order of a few cGy, whilst with the scintigraphic method differences of up to 8 Gy were observed. A manipulation technique is also presented which allows 3D scintigraphic dosimetry measurements to be compared to polymer gel dosimetry measurements without generating misleading errors due to the limited spatial resolution.

Duodenal ulcer disease, gastroduodenal motor function and reflux esophagitis – a cross‐sectional survey in a subset of Taiwanese patients

To investigate the association between the gastric emptying rate and the presence of erosive esophagitis in duodenal ulcer (DU) patients among a population with high prevalence of Helicobacter pylori infection. Cross-sectional survey was performed in a cohort of 60 male patients with either active or healed DU, with or without the presence of erosive esophagitis. Clinical and social-demographic data, blood level of fasting gastrin, pepsinogen I & I/II ratio, and scintigraphic measurement of half emptying time (t(1/2) ) of the solid phase gastric emptying were evaluated. Patients with active DU and erosive esophagitis tended to have higher plasma level of fasting gastrin than those without erosive esophagitis (75.11±13.74 vs 45.81±5.06pgmL(-1) , P = 0.059). In the absence of H. pylori infection, patients with healed DU and erosive esophagitis had a trend to have longer half-emptying time (t(1/2) : 96.5±6.4 vs 69.1±11.3min, P=0.0572) than those without erosive esophagitis, and statistically significant longer after excluding those diagnosed with hiatal hernia (t(1/2) : 100.8±7.9min vs 69.1±11.3min, P<0.05) from the former group. Among the healed DU patients, those with negative H. pylori infection, hiatal hernia and overweight (body mass index ≥24) had significantly increased risk of severe esophagitis. Presence of erosive esophagitis in a subset of Taiwanese patients with healed DU and negative H. pylori status was associated with slower solid phase gastric emptying.

Clinical diagnoses reached in patients undergoing combined ambulatory ph and impedance monitoring for symptoms suspected to be secondary to reflux disease refractory to acid suppression

IntroductionSince August 2007 we have employed combined ambulatory pH and impedance monitoring in the investigation of patients with symptoms thought attributable to gastro-oesophageal reflux refractory to acid suppression. The aim...