PULMONARY NODULE DETECTION IN CHEST CT USING A DEEP LEARNING-BASED RECONSTRUCTION ALGORITHM.

This study's aim was to assess whether deep learning image reconstruction (DLIR) techniques are non-inferior to ASIR-V for the clinical task of pulmonary nodule detection in chest computed tomography. Up to 6 (range 3-6, mean 4.2) artificial lung nodules (diameter: 3, 5, 8 mm; density: -800, -630, +100 HU) were inserted at different locations in the Kyoto Kagaku Lungman phantom. In total, 16 configurations (10 abnormal, 6 normal) were scanned at 7.6, 3, 1.6 and 0.38 mGy CTDIvol (respectively 0, 60, 80 and 95% dose reduction). Images were reconstructed using 50% ASIR-V and a deep learning-based algorithm with low (DL-L), medium (DL-M) and high (DL-H) strength. Four chest radiologists evaluated 256 series by locating and scoring nodules on a five-point scale. No statistically significant difference was found among the reconstruction algorithms (p = 0.987, average across readers AUC: 0.555, 0.561, 0.557, 0.558 for ASIR-V, DL-L, DL-M, DL-H).

Vague abdominal pain after Roux-en-Y gastric bypass: not always an internal herniation: case report and literature review.

Background: Roux-en-Y gastric bypass is a frequently carried out bariatric procedure, proven to be effective in the management of obesity and its accompanying health issues. Following its popularity, admission to the emergency department for abdominal pain is often seen with known early and late onset causes. We present a case of a young woman with vague abdominal pain years after her gastric bypass, who eventually underwent a resection of a 'candy cane' like biliopancreatic blind loop.Methods: A healthy 23-year-old woman has been suffering of vague abdominal complaints after a gastric bypass procedure 4 years earlier. Postprandial pain, diarrhoea and abdominal distension were present at a daily to weekly basis. Several investigations and management options were administered by surgeons, gastroenterologists as well as endocrinologists. On a performed explorative laparoscopy, a large blind loop at the entero-enteric anastomosis was seen and resected.Results: At current follow-up of 15 months the resection of the candy cane like blind end of the biliopancreatic loop resulted in a complete withdrawal of our patient's symptoms. A tentative diagnosis of bacterial overgrowth in the blind loop was made.Conclusions: Abdominal pain after gastric bypass is a frequent cause of admission to the emergency department. Besides the more serious complications, internal hernia is often withheld as possible diagnosis in the differential diagnosis of late onset, postprandial epigastric pain. This case report highlights another possibility. At initial surgery, a candy cane shaped blind loop should be avoided both at the gastro-jejunal as well as the entero-enteric anastomosis.

Lesion detection on a combined "All-in-One" window compared to conventional window settings in thoracic oncology chest CT examinations.

PURPOSE: The purpose of this study was to investigate if lesion detection using a single "All-in-One" (AIO) window was non-inferior to lesion detection on conventional window settings in thoracic oncology chest computed tomography (CT) examinations. MATERIALS AND METHODS: In a retrospective study, 50 consecutive chest CT examinations of 50 patients (31 men, 19 women; mean age 64±10 [SD] years, range: 35-82 years) containing 417 lesions, were reviewed by 6 radiologists, subdivided into 2 groups of 3 radiologists each, with similar levels of expertise in each group (senior staff member, junior staff member and radiology resident). All examinations were reviewed in conventional or AIO window settings by one of the groups. A 'lesion' was defined as any abnormality seen on the chest CT examination, including both benign and malignant lesions, findings in chest and upper abdomen, and measurable and non-measurable disease. Lesions were listed as 'missed' when they were not seen by at least two out of three observers. F-tests were used to evaluate the significance of the variables of interest within a mixed model framework and kappa statistics to report interobserver agreement. RESULTS: On a reader level, 54/417 lesions (12.9%) were not detected by the senior staff member reading the studies in conventional window settings and 45/417 (10.8%) by the senior staff member reading the AIO images. For the junior staff member and radiology resident this was respectively 55/417 (13.2%) and 67/417 (16.1%) for the conventional window settings and 43/417 (10.3%) and 61/417 (14.6%) for the AIO window. On a lesion level, 68/417 (16.3%) were defined as 'missed' lesions (lesions not detected by at least 2 readers): 21/68 (30.9%) on the AIO-window, 30/68 (44.1%) on conventional views and 17/68 (25.0%) on both views. The use of the AIO window did not result in an increase of missed lesions (P>0.99). Interobserver agreement in both groups was similar (P=0.46). Regarding lesions that were categorized as 'missed' on the AIO window or on conventional window settings, there was no effect of location (chest or upper abdomen) (P=0.35), window (P=0.97) and organ (P=0.98). CONCLUSIONS: A single AIO-window is non-inferior to multiple conventional window settings for lesion detection on chest CT examinations in thoracic oncology patients.

The Endovascular Treatment of Epistaxis.

Epistaxis or nosebleed is relatively common in the general population. Depending on the location of the bleeding in the nasal cavity, epistaxis can be divided in two types: anterior or posterior type. The anterior type is far more frequent, often self-limiting and, if needed, is relatively easy treatable. Posterior type epistaxis is rare and more likely to require medical attention. The cornerstone of the conservative therapy of posterior epistaxis is nasal packing. Only in patients with persistent or recurrent epistaxis, endovascular intervention or surgery is indicated. Both treatment options have a similar success and complication rate, but endovascular treatment, if feasible, has several advantages above surgical treatment. The choice of procedure should be made on a patient-to-patient basis, taking several parameters into account. In this pictorial essay we present an overview of the relevant radiological anatomy and a review of various causes of epistaxis, with the emphasis on the endovascular treatment.

Bifractality of human DNA strand-asymmetry profiles results from transcription.

We use the wavelet transform modulus maxima method to investigate the multifractal properties of strand-asymmetry DNA walk profiles in the human genome. This study reveals the bifractal nature of these profiles, which involve two competing scale-invariant (up to repeat-masked distances less, or similar 40 kbp) components characterized by Hölder exponents h{1}=0.78 and h{2}=1, respectively. The former corresponds to the long-range-correlated homogeneous fluctuations previously observed in DNA walks generated with structural codings. The latter is associated with the presence of jumps in the original strand-asymmetry noisy signal S. We show that a majority of upward (downward) jumps co-locate with gene transcription start (end) sites. Here 7228 human gene transcription start sites from the refGene database are found within 2 kbp from an upward jump of amplitude DeltaS > or = 0.1 which suggests that about 36% of annotated human genes present significant transcription-induced strand asymmetry and very likely high expression rate.

DNA replication timing data corroborate in silico human replication origin predictions.

We develop a wavelet-based multiscale pattern recognition methodology to disentangle the replication- from the transcription-associated compositional strand asymmetries observed in the human genome. Comparing replication skew profiles to recent high-resolution replication timing data reveals that most of the putative replication origins that border the so-identified replication domains are replicated earlier than their surroundings whereas the central regions replicate late in the S phase. We discuss the implications of this first experimental confirmation of these replication origin predictions that are likely to be early replicating and active in most tissues.

Functional modes of proteins are among the most robust.

It is shown that a small subset of modes which are likely to be involved in protein functional motions of large amplitude can be determined by retaining the most robust normal modes obtained using different protein models. This result should prove helpful in the context of several applications proposed recently, like for solving difficult molecular replacement problems or for fitting atomic structures into low-resolution electron density maps. It may also pave the way for the development of methods allowing us to predict such motions accurately.

From DNA sequence analysis to modeling replication in the human genome.

We explore the large-scale behavior of nucleotide compositional strand asymmetries along human chromosomes. As we observe for 7 of 9 origins of replication experimentally identified so far, the (TA+GC) skew displays rather sharp upward jumps, with a linear decreasing profile in between two successive jumps. We present a model of replication with well positioned replication origins and random terminations that accounts for the observed characteristic serrated skew profiles. We succeed in identifying 287 pairs of putative adjacent replication origins with an origin spacing approximately 1-2 Mbp that are likely to correspond to replication foci observed in interphase nuclei and recognized as stable structures that persist throughout subsequent cell generations.

Low frequency rhythms in human DNA sequences: a key to the organization of gene location and orientation?

We explore large-scale nucleotide compositional fluctuations of the human genome using multiresolution techniques. Analysis of the GC content and of the AT and GC skews reveals the existence of rhythms with two main periods of 110+/-20 kb and 400+/-50 kb that enlighten a remarkable cooperative gene organization. We show that the observed nonlinear oscillations are likely to display all the characteristic features of chaotic strange attractors which suggests a very attractive deterministic picture: gene orientation and location, in relation with the structure and dynamics of chromatin, might be governed by a low-dimensional nonlinear dynamical system.

Transcription-coupled TA and GC strand asymmetries in the human genome.

Analysis of the whole set of human genes reveals that most of them present TA and GC skews, that these biases are correlated to each other and are specific to gene sequences, exhibiting sharp transitions between transcribed and non-transcribed regions. The GC asymmetries cannot be explained solely by a model previously proposed for (G+T) skew based on transitions measured in a small set of human genes. We propose that the GC skew results from additional transcription-coupled mutation process that would include transversions. During evolution, both processes acting on a large majority of genes in germline cells would have produced these transcription-coupled strand asymmetries.