Statistical significance : p value, 0.05 threshold, and applications to radiomics—reasons for a conservative approach

Here, we summarise the unresolved debate about p value and its dichotomisation. We present the statement of the American Statistical Association against the misuse of statistical significance as well as the proposals to abandon the use of p value and to reduce the significance threshold from 0.05 to 0.005. We highlight reasons for a conservative approach, as clinical research needs dichotomic answers to guide decision-making, in particular in the case of diagnostic imaging and interventional radiology. With a reduced p value threshold, the cost of research could increase while spontaneous research could be reduced. Secondary evidence from systematic reviews/meta-analyses, data sharing, and cost-effective analyses are better ways to mitigate the false discovery rate and lack of reproducibility associated with the use of the 0.05 threshold. Importantly, when reporting p values, authors should always provide the actual value, not only statements of \u201cp < 0.05\u201d or \u201cp 65 0.05\u201d, because p values give a measure of the degree of data compatibility with the null hypothesis. Notably, radiomics and big data, fuelled by the application of artificial intelligence, involve hundreds/thousands of tested features similarly to other \u201comics\u201d such as genomics, where a reduction in the significance threshold, based on well-known corrections for multiple testing, has been already adopted

May antitransglutaminase levels predict severity of duodenal lesions in adults with celiac disease?

Background and Objective: Pediatric guidelines on celiac disease (CD) state that children with anti‐transglutaminase antibodies (TGAs) >×10 upper limit of normal (ULN) may avoid endos-copy and biopsy. We aimed to evaluate whether these criteria may be suitable for villous atrophy diagnosis in CD adults. Materials and Methods: We retrospectively enrolled patients with CD aged >18 years. TGAs were expressed as xULN. Duodenal lesions were classified as atrophic or non-atrophic according to Marsh‐Oberhuber. Fisher’s exact and t‐test were used for variables compari-son. Receiver operating characteristics (ROC) curve analysis was performed with estimation of area under the curve (AUC), sensitivity, specificity, and positive and negative predictive value (PPV/NPV). Results: One hundred and twenty‐one patients were recruited. Sixty patients (49.6%) had TGA >×10 ULN, and 93 (76.8%) had villous atrophy. The cut‐off of >×10 ULN had sensitivity = 53.7%, specificity = 64.3%, PPV = 83.3%, and NPV = 29.5% to predict atrophy. Therefore, considering pediatric criteria, in 50 (41.3%) patients, biopsy could have been avoided. Patient subgroup with atrophy had higher TGA levels despite being not significant (37.2 ± 15.3 vs. 8.0 ± 1.3 ULN, p = 0.06). In adults, a slightly better diagnostic performance was obtained using a cut‐off of TGA >×6.2 ULN (sensitivity = 57.1%, specificity = 65.6%, and AUC = 0.62). Conclusions: Despite our confirmation that villous atrophy is linked to high TGA levels, CD and atrophy diagnosis based only on serology is not reliable in adults

Severe anaemia after gastric biopsy in an infant with eosinophilic gastritis

Background: Eosinophilic gastrointestinal disorders (EGID) are characterized by eosinophilic inflammation and are subclassified according to the affected site(s) as eosinophilic esophagitis, eosinophilic gastritis, eosinophilic enteritis and eosinophilic colitis. Clinical presentation includes dyspeptic symptoms, vomiting, abdominal pain, diarrhoea and gastrointestinal bleeding. Peripheral eosinophilia is usually found but is not required for the diagnosis. The treatment is based on dietary elimination therapy, consisting of removal of common food triggers, most frequently cow's milk in infants. Corticosteroids are used as first line drug therapy in EG if dietary therapy fails to achieve an adequate clinical response or is impractical. Case presentation: A four month old infant was admitted for an episode of melena and hematemesis. An esophagogastroduodenoscopy showed haemorrhagic gastritis with ulcerative lesions and fibrin. A significant gastric bleeding was noted after the procedure. The gastric mucosa biopsies showed an eosinophilic infiltration. Conclusions: A clinically relevant anaemia is a quite rare complication in infants with eosinophilic gastritis and a biopsy may worsen bleeding, to a potentially severe level of low haemoglobin. In infants with low haemoglobin levels and suspect eosinophilic gastritis a watchful follow up after the biopsy should be considered, as well as the possibility of postponing the biopsy to reduce the bleeding risk

Possibile origine e consistenza di un popolamento di Quercus trojana Webb subsp. trojana (Fagaceae) nel Bosco della Ficuzza (Palermo, Sicilia

Possible origin and demographic asset of a population of Quercus trojana Webb subsp. trojana (Fagaceae) in the wood of Ficuzza (Palermo, Sicily). The first record of Macedonian oak in Sicily is reported. The finding consists of 73 adult and 4 young individuals. A morphometric analysis of all of them, along with an assessment of their phytosanitary status was carried out. They all grow between 700 and 850 m a.s.l. on a 2,30 ha area, characterized by a land mosaic of shrubland and forest patches. Notwithstanding two years of researches, no ultimate proof has been found on their alien status. On this purpose, several alternative hypothesis are formulated and their strengths and weaknesses are discussed. Considering that the environmental conditions of Ficuzza fit very well the ecological requirements of Quercus trojana, even the native status of local population cannot be totally rejected. On the other hand, many data support its recent introduction. In fact, according to interviews to old forest workers, archive documents and aerial photos, most part of the trees of this area have been planted just few years after the end of the Second World War, and dendrochronological analyses have pointed out that the biggest Macedonian oaks of Sicily are no more than 50-60 years old. Whatever the origin of local Macedonian oak population is, the presence of natural renovation testifies, at least, its full naturalisation within the Sicilian territory

Statistical image processing for the detection of dermoscopic criteria

An image based system implementing a well-known diagnostic method is disclosed for the automatic detection of melanomas as support to clinicians. The software procedure is able to recognize automatically the skin lesion within the digital image, measure morphological and chromatic feature, carry out a suitable classification for the detection of structural dermoscopic criteria provided by the 7-Point Check List. Experimental results about the adoption of statistical techniques applied to the border detection, feature extraction and classification as well as the resulting diagnostic score are described with reference to a large image set. Copyright © 2011 by the International Measurement Confederation (IMEKO) All rights reserved

Unarousable child with a short bowel

Unarousable child with short bowel: A 4-year-old boy was admitted with progressive lethargy of a few hours' duration and no other symptoms. His medical history was relevant for short bowel syndrome (SBS), following neonatal volvulus, with residual bowel length of 23 cm and intact ileocecal valve. He had similar self-limiting episodes in the past, after weaning parenteral nutrition, especially after eating large meals. The day before, he had consumed a large amount of apples. Arterial blood gas (ABG) analysis showed metabolic acidosis with normal lactacidaemia (pH 7.09, pCO2 19 mm Hg, pO2 101 mm Hg, HCO3 5.8 mmol/L, BE -24, anion gap 29.4, chloride 116 mmol/L, L-lactate level 4 mmol/L). On admission, the child could be awakened, but he was confused with slurred speech (Glasgow Coma Scale 14), with a body temperature of 37 C°, a heart rate of 125 beats/min and a respiratory rate of 38 breaths/min. The abdomen was distended, without guarding and with normal bowel sounds. Blood glucose levels were normal, as well as white blood cell count, liver and kidney function test and C reactive protein. An abdominal ultrasound ruled out an intussusception. An abdominal X-ray was performed too (seefigure 1). Figure 1 Abdominal distension with gas and bloating. Questions: Which is the most likely diagnosis? Encephalitis D-lactic acidosis Dehydration with third space fluid collection and acidosis Hereditary fructose intolerance. How is this diagnosis confirmed? D lactic dosage Breath test for bacterial overgrowth Urine organic acid dosage Search for reductive substances in the stools. How should this patient be managed? Intravenous fluids to facilitate D-lactic excretion Restrict carbohydrates in the diet Intravenous bicarbonates Antibiotic treatment to reduce bowel bacterial overgrowth. Answers can be found on page 2

CT colonography followed by elective surgery in patients with acute diverticulitis : a radiological-pathological correlation study

Purpose: To perform a radiologic-pathologic correlation analysis of sigmoid colon in patients undergoing pre-operative CT Colonography (CTC) after an episode of acute diverticulitis (AD). Methods: Fifty-nine consecutive patients (31/28 M/F; 58 \ub1 13 years) underwent CTC 55 \ub1 18 days after AD, 8 \ub1 4 weeks before surgery. Thirty-seven patients (63%) underwent conventional abdominal CT at time of AD. An experienced blinded radiologist retrospectively analyzed all images: disease severity was graded according to the Ambrosetti classification on conventional CT and according to the diverticular disease severity score (DDSS) on CTC. A GI pathologist performed a dedicated analysis, evaluating the presence of acute and chronic inflammation, and fibrosis, using 0\u20133 point scale for each variable. Results: Of 59 patients, 41 (69%) had at least one previous AD episode; twenty-six patients (44%) had a complicated AD. DDSS was mild-moderate in 34/59 (58%), and severe in 25/59 (42%). All patients had chronic inflammation, while 90% had low-to-severe fibrosis. Patients with moderate/severe fibrosis were older than those with no/mild fibrosis (61 \ub1 13 versus 54 \ub1 13). We found a significant correlation between DDSS and chronic inflammation (p = 0.004), as well as DDSS and fibrosis (p = 0.005). Furthermore, fibrosis was correlated with complicated acute diverticulitis (p = 0.0.27), and with age (p = 0.067). At multivariate analysis, complicated diverticulitis was the best predictor of fibrosis (odds ratio 4.4). Patient age and DDSS were other independent predictors. Conclusion: DDSS-based assessment on preoperative CTC was a good predictor of chronic colonic inflammation and fibrosis. In addition, the presence of complicated diverticulitis on CT during the acute episode was most predictive of fibrosis

Experimental testing of a horizontal-axis wind turbine to assess its performance

This paper describes a test procedure to investigate the performance of a micro wind turbine with horizontal-axis. A 3D model of a rotor with five blades has been designed by a MATLAB software; its airfoil is optimized to efficiently work at low wind speed. The rotor is coupled to an electric generator and this equipment is tested in a wind tunnel. An anemometer is used to measure and set the desired wind speeds. Electric quantities, i.e., voltage, current and power, are acquired by a digital multimeter. A variable resistance is used to change the operating point of the generator. Preliminary results are reported that refer to the application of the proposed test procedures to a wind turbine with a 0.2 m2 swept area