Incidence and importance of portal venous gas in children with hypertrophic pyloric stenosis.

BACKGROUND: Hypertrophic pyloric stenosis (HPS) is a common cause of gastric outlet obstruction in young infants. Infants with HPS present with projectile vomiting, sometimes have electrolyte abnormalities and typically undergo pyloromyotomy to alleviate the obstruction. Abdominal US is the gold standard imaging study for diagnosis. Case reports of incidental hepatic portal venous gas have been reported in infants with HPS; however, no large studies have been conducted to determine the incidence or possible clinical implications of this finding. OBJECTIVE: To assess the incidence of portal venous gas in infants with HPS and to determine whether the presence of this gas in infants with HPS indicates a more unstable patient, increased length of stay or worse outcome. MATERIALS AND METHODS: We conducted a retrospective review of sonographic reports containing "pyloric stenosis," excluding negative descriptor, at a tertiary-care children's hospital from November 2010 to September 2017. Data collected included pyloric thickness/length, liver evaluation, portal venous gas, any additional imaging, demographics, symptomatology days, electrolyte abnormality, and length of hospital stay. RESULTS: In a 7-year period, 545 US exams were positive for HPS. Of these, 334 exams included enough hepatic parenchyma to evaluate for portal venous gas. Infants in 6 of the 334 exams demonstrated portal venous gas (1.8%). Clinical presentation (length of symptoms and electrolyte abnormalities), demographics (male predominance and age at presentation) and imaging characteristics (pyloric thickness and length) were similar for the HPS groups with and without portal venous gas. There was no significant difference in outcome or length of hospital stay. CONCLUSION: Visualization of portal venous gas in infants with HPS is not rare and appears benign, without need for further imaging. Portal venous gas in infants with HPS does not portend a more severe patient presentation or outcome.

Positron Emission Mammography Image Interpretation for Reduced Image Count Levels.

UNLABELLED: We studied the effects of reduced (18)F-FDG injection activity on interpretation of positron emission mammography (PEM) images and compared image interpretation between 2 postinjection imaging times. METHODS: We performed a receiver-operating-characteristic (ROC) study using PEM images reconstructed with different count levels expected from injected activities between 23 and 185 MBq. Thirty patients received 2 PEM scans at postinjection times of 60 and 120 min. Half of the patients were scanned with a standard protocol; the others received one-half of the standard activity. Images were reconstructed using 100%, 50%, and 25% of the total counts acquired. Eight radiologists used a 5-point confidence scale to score 232 PEM images for the presence of up to 3 malignant lesions. Paired images were analyzed with conditional logistic regression and ROC analysis to investigate changes in interpretation. RESULTS: There was a trend for increasing lesion detection sensitivity with increased image counts: odds ratios were 2.2 (P = 0.01) and 1.9 (P = 0.04) per doubling of image counts for 60- and 120-min uptake images, respectively, without significant difference between time points (P = 0.7). The area under the ROC curve (AUC) was highest for the 100%-count, 60-min images (0.83 vs. 0.75 for 50%-counts, P = 0.02). The 120-min images had a similar trend but did not reach statistical significance (AUC = 0.79 vs. 0.73, P = 0.1). Our data did not yield significant trends between specificity and image counts. Lesion-to-background ratios increased between 60- and 120-min scans (P < 0.001). CONCLUSION: Reducing the image counts relative to the standard protocol decreased diagnostic accuracy. The increase in lesion-to-background ratio between 60- and 120-min uptake times was not enough to improve detection sensitivity in this study, perhaps in part due to fewer counts in the later scan.

Positron emission mammography (PEM): effect of activity concentration, object size, and object contrast on phantom lesion detection.

PURPOSE: To characterize the relationship between lesion detection sensitivity and injected activity as a function of lesion size and contrast on the PEM (positron emission mammography) Flex Solo II scanner using phantom experiments. METHODS: Phantom lesions (spheres 4, 8, 12, 16, and 20 mm diameter) were randomly located in uniform background. Sphere activity concentrations were 3 to 21 times the background activity concentration (BGc). BGc was a surrogate for injected activity; BGc ranged from 0.44-4.1 kBq∕mL, corresponding to 46-400 MBq injections. Seven radiologists read 108 images containing zero, one, or two spheres. Readers used a 5-point confidence scale to score the presence of spheres. RESULTS: Sensitivity was 100% for lesions ≥12 mm under all conditions except for one 12 mm sphere with the lowest contrast and lowest BGc (60% sensitivity). Sensitivity was 100% for 8 mm spheres when either contrast or BGc was high, and 100% for 4 mm spheres only when both contrast and BGc were highest. Sphere contrast recovery coefficients (CRC) were 49%, 34%, 26%, 14%, and 2.8% for the largest to smallest spheres. Cumulative specificity was 98%. CONCLUSIONS: Phantom lesion detection sensitivity depends more on sphere size and contrast than on BGc. Detection sensitivity remained ≥90% for injected activities as low as 100 MBq, for lesions ≥8 mm. Low CRC in 4 mm objects results in moderate detection sensitivity even for 400 MBq injected activity, making it impractical to optimize injected activity for such lesions. Low CRC indicates that when lesions <8 mm are observed on PEM images they are highly tracer avid with greater potential of clinical significance. High specificity (98%) suggests that image statistical noise does not lead to false positive findings. These results apply to the 85 mm thick object used to obtain them; lesion detectability should be better (worse) for thinner (thicker) objects based on the reduced (increased) influence of photon attenuation.

Identifying minimally acceptable interpretive performance criteria for screening mammography.

PURPOSE: To develop criteria to identify thresholds for minimally acceptable physician performance in interpreting screening mammography studies and to profile the impact that implementing these criteria may have on the practice of radiology in the United States. MATERIALS AND METHODS: In an institutional review board-approved, HIPAA-compliant study, an Angoff approach was used in two phases to set criteria for identifying minimally acceptable interpretive performance at screening mammography as measured by sensitivity, specificity, recall rate, positive predictive value (PPV) of recall (PPV(1)) and of biopsy recommendation (PPV(2)), and cancer detection rate. Performance measures were considered separately. In phase I, a group of 10 expert radiologists considered a hypothetical pool of 100 interpreting physicians and conveyed their cut points of minimally acceptable performance. The experts were informed that a physician's performance falling outside the cut points would result in a recommendation to consider additional training. During each round of scoring, all expert radiologists' cut points were summarized into a mean, median, mode, and range; these were presented back to the group. In phase II, normative data on performance were shown to illustrate the potential impact cut points would have on radiology practice. Rescoring was done until consensus among experts was achieved. Simulation methods were used to estimate the potential impact of performance that improved to acceptable levels if effective additional training was provided. RESULTS: Final cut points to identify low performance were as follows: sensitivity less than 75%, specificity less than 88% or greater than 95%, recall rate less than 5% or greater than 12%, PPV(1) less than 3% or greater than 8%, PPV(2) less than 20% or greater than 40%, and cancer detection rate less than 2.5 per 1000 interpretations. The selected cut points for performance measures would likely result in 18%-28% of interpreting physicians being considered for additional training on the basis of sensitivity and cancer detection rate, while the cut points for specificity, recall, and PPV(1) and PPV(2) would likely affect 34%-49% of practicing interpreters. If underperforming physicians moved into the acceptable range, detection of an additional 14 cancers per 100000 women screened and a reduction in the number of false-positive examinations by 880 per 100000 women screened would be expected. CONCLUSION: This study identified minimally acceptable performance levels for interpreters of screening mammography studies. Interpreting physicians whose performance falls outside the identified cut points should be reviewed in the context of their specific practice settings and be considered for additional training.

1,5-anhydroglucitol and postprandial hyperglycemia as measured by continuous glucose monitoring system in moderately controlled patients with diabetes.

OBJECTIVE: Postprandial hyperglycemia is often inadequately assessed in diabetes management. Serum 1,5-anhydroglucitol (1,5-AG) drops as serum glucose rises above the renal threshold for glucose and has been proposed as a marker for postprandial hyperglycemia. The objective of this study is to demonstrate the relationship between 1,5-AG and postprandial hyperglycemia, as assessed by the continuous glucose monitoring system (CGMS) in suboptimally controlled patients with diabetes. RESEARCH DESIGN AND METHODS: Patients with type 1 or type 2 diabetes and an HbA(1c) (A1C) between 6.5 and 8% with stable glycemic control were recruited from two sites. A CGMS monitor was worn for two consecutive 72-h periods. Mean glucose, mean postmeal maximum glucose (MPMG), and area under the curve for glucose above 180 mg/dl (AUC-180), were compared with 1,5-AG, fructosamine (FA), and A1C at baseline, day 4, and day 7. RESULTS: 1,5-AG varied considerably between patients (6.5 +/- 3.2 mug/ml [means +/- SD]) despite similar A1C (7.3 +/- 0.5%). Mean 1,5-AG (r = -0.45, P = 0.006) correlated with AUC-180 more robustly than A1C (r = 0.33, P = 0.057) or FA (r = 0.38, P = 0.88). MPMG correlated more strongly with 1,5-AG (r = -0.54, P = 0.004) than with A1C (r = 0.40, P = 0.03) or FA (r = 0.32, P = 0.07). CONCLUSIONS: 1,5-AG reflects glycemic excursions, often in the postprandial state, more robustly than A1C or FA. 1,5-AG may be useful as a complementary marker to A1C to assess glycemic control in moderately controlled patients with diabetes.