scholarly journals Spectral CT Hybrid Images in the Diagnostic Evaluation of Hypervascular Abdominal Tumors—Potential Advantages in Clinical Routine

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1539
Author(s):  
Timo Alexander Auer ◽  
Felix Wilhelm Feldhaus ◽  
Laura Büttner ◽  
Martin Jonczyk ◽  
Uli Fehrenbach ◽  
...  
Keyword(s):  
Reading Time ◽  
Image Contrast ◽  
Primary Hepatocellular Carcinoma ◽  
Neuroendocrine Neoplasms ◽  
Diagnostic Confidence ◽  
Additional Information ◽  
Abdominal Tumors ◽  
Set Agreement ◽  
Potential Reading ◽  
Suspicious Lesions

Background: This study aimed to investigate the use of spectral computed tomography (SCT) hybrid images combining virtual monoenergetic images (VMIs) and iodine maps (IMs) as a potentially efficient search series for routine clinical imaging in patients with hypervascular abdominal tumors. Methods: A total of 69 patients with hypervascular abdominal tumors including neuroendocrine neoplasms (NENs, n = 48), renal cell carcinoma (RCC, n = 10), and primary hepatocellular carcinoma (HCC, n = 11) were analyzed retrospectively. Two radiological readers (blinded to clinical data) read three CT image sets (1st a reference set with 70 keV; 2nd a 50:50 hybrid 140 keV/40 keV set; 3rd a 50:50 hybrid140 keV/IM set). They assessed images subjectively by rating several parameters including image contrast, visibility of suspicious lesions, and diagnostic confidence on five-point Likert scales. In addition, reading time was estimated. Results: Median subjective Likert scores were highest for the 1st set, except for image contrast, for which the 2nd set was rated highest. Scores for diagnostic confidence, artifacts, noise, and visibility of suspicious lesions or small structures were significantly higher for the 1st set than for the 2nd or 3rd set (p < 0.001). Regarding image contrast, the 2nd set was rated significantly higher than the 3rd set (p < 0.001), while the median did not differ significantly compared with the 1st set. Agreement between the two readers was high for all sets. Estimated potential reading time was the same for hybrid and reference sets. Conclusions: Hybrid images have the potential to efficiently exploit the additional information provided by SCT in patients with hypervascular abdominal tumors. However, the use of rigid weighting did not significantly improve diagnostic performance in this study.

Clinical routine use of virtual monochromatic datasets based on spectral CT in patients with hypervascularized abdominal tumors - evaluation of effectiveness and efficiency

2018 ◽  
Vol 60 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Georg Böning ◽  
Felix Feldhaus ◽  
Sebastian Adelt ◽  
Johannes Kahn ◽  
Uli Fehrenbach ◽  
...  
Keyword(s):  
Image Quality ◽  
Reading Time ◽  
Signal To Noise Ratio ◽  
Low Energy ◽  
Arterial Phase ◽  
Diagnostic Confidence ◽  
Clinical Routine ◽  
Portal Venous Phase ◽  
Abdominal Tumors ◽  
Oncologic Patients

Background Virtual monochromatic images (VMI) generated using spectral computed tomography (CT) are promising recently available tools to improve diagnostic performance in oncologic patients. Purpose To investigate if virtual monochromatic datasets are suitable for clinical routine use in patients with hypervascularized abdominal tumors. Material and Methods A total of 41 patients with hypervascularized hepatocellular carcinoma (HCC), renal cell carcinoma (RCC), or neuroendocrine tumors (NET) were enrolled in the study; 451 CT series were analyzed. In an intra-individual study design, virtual monochromatic datasets of the arterial phase of each scan were computed. Image quality was assessed objectively by determining signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) and subjectively by using five-point Likert-scales. The volume CT dose index (CTDIvol) was taken from each radiation dose report. The increase in reading time was estimated from the increase in the number of images. Results Intra-individual comparison of the spectral mode in the arterial phase with the portal venous phase revealed no significant increase in the applied dose. SNR, CNRtumor-to-liver , and CNRtumor-to-muscle were significantly increased by lowering virtual monochromatic energy. Subjective image quality scores revealed an increase of contrast in low energy datasets, resulting in significantly higher diagnostic confidence, but an increased image noise at low energies. While diagnostic confidence improved, taking all datasets into account resulted in a significantly longer estimated reading time. Conclusion In clinical practice, the use of low energy VMI improved diagnostic confidence without a significant increase in dose. The main disadvantage is a decrease in efficiency due to longer reading times.

scholarly journals Paragangliomas the Forgotten Neuroendocrine Neoplasms: A Retrospective Review of 237 Cases From 2 Centers in 2 Years

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A90-A91
Author(s):  
Claudia Ramirez-Renteria ◽  
Alejandra Albarran-Sanchez ◽  
David Enrique Hernandez-Calderon ◽  
Pattsy Etual Espinosa Cardenas ◽  
Ernesto Sosa ◽  
...  
Keyword(s):  
Retrospective Review ◽  
Neuroendocrine Neoplasms ◽  
Abdominal Tumors ◽  
Cranial Nerve Palsies ◽  
Icd 10 ◽  
Parametric Statistics ◽  
Uniform Nomenclature ◽  
Thoracic And Abdominal ◽  
Lost To Follow Up

Abstract Background: paragangliomas (PGN) (including adrenal PGN or pheochromocytomas) are uncommon neuroendocrine neoplasias. Their ubiquity and lack of uniform nomenclature has resulted in systematic sub-registry and limited resources for patients and clinicians. However, 40% of them are hereditary, 10–20% are hormonally active and 50% result in treatment-related complications. Objectives: to describe the clinical and biochemical characteristics of PGN in two referral centers in a 2-year period. Materials and Methods: a retrospective review of the files of patients evaluated in the Centro Medico Nacional Siglo XXI or the Instituto Nacional de Neurología y Neurocirugia between June 2018 and May 2020, even if diagnosis was prior to those dates. The search was performed using ICD-10 terms in the outpatient registries. Data is described using non-parametric statistics, including medians (interquartilic ranges, IQR). According to the reported incidences we expected to find 35 new cases per year in each hospital. Results: 237 patients, 86.4% female with a median age at diagnosis of 54 years (IQR 45–64) were found. The tumors were located in the head 23.9%, neck 63.3%, thorax 0.4%, adrenal in 11.1%, other sites in the abdomen 1.3%. The most common symptoms in head PGN were hypoacusia (85.2%) and cranial nerve palsies (39.3%), in the neck, a visible mass and pain (30.6%) while the “classic” catecholaminergic symptoms were more common in thoracic and abdominal tumors (&gt;50%). Tumors were large or invasive in 50.1% of the cases and at least one hormone was above the upper limit of normal (ULN) in 40.6% of the 64 evaluated cases, mostly urinary dopamine (70% of cases tested, 1.1–2.1 ULN) and plasma and urine metanephrines (60% of cases tested, 1.1- 33.7 ULN and 50% cases, 1.1–22 ULN, respectively). Severe systolic hypertension was more frequent in male patients &lt;30 years of age and 41.6% were candidates to genetic testing due to the tumor characteristics or patient history. Surgery was performed in 55.6%, radiotherapy in 25.2% and 12.1% are under surveillance or pending surgery, 7.1% were lost to follow up. Only 5 cases with metastasis were documented in 1215 patient-years of follow-up. Treatment-related complications were reported in 14.7% and persistence in 32.2%. Conclusions: despite the retrospective nature of the study and sub registry, we found more tumors than expected. The frequency of hormonal production was high, but it is likely related to patient selection bias (mostly symptomatic cases studied). Dopamine and metanephrines are useful in the evaluation of PGN. Endocrinologists should be aware of these common tumors and be part of the multidisciplinary team.

scholarly journals Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers

2019 ◽  
Vol 26 (3) ◽  
pp. R157-R179 ◽  
Author(s):  
Aura D Herrera-Martínez ◽  
Leo J Hofland ◽  
María A Gálvez Moreno ◽  
Justo P Castaño ◽  
Wouter W de Herder ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Somatostatin Analogs ◽  
Unmet Need ◽  
Neuroendocrine Neoplasms ◽  
Additional Information ◽  
Dna And Rna ◽  
Variable Sensitivity ◽  
Gene Transcripts ◽  
Novel Biomarkers ◽  
New Biomarkers

Some biomarkers for functioning and non-functioning neuroendocrine neoplasms (NENs) are currently available. Despite their application in clinical practice, results should be interpreted cautiously. Considering the variable sensitivity and specificity of these parameters, there is an unmet need for novel biomarkers to improve diagnosis and predict patient outcome. Nowadays, several new biomarkers are being evaluated and may become future tools for the management of NENs. These biomarkers include (1) peptides and growth factors; (2) DNA and RNA markers based on genomics analysis, for example, the so-called NET test, which has been developed for analyzing gene transcripts in circulating blood; (3) circulating tumor/endothelial/progenitor cells or cell-free tumor DNA, which represent minimally invasive methods that would provide additional information for monitoring treatment response and (4) improved imaging techniques with novel radiolabeled somatostatin analogs or peptides. Below we summarize some future directions in the development of novel diagnostic and predictive/prognostic biomarkers in NENs. This review is focused on circulating and selected tissue markers.

scholarly journals The value of deep learning-based computer aided diagnostic system in improving diagnostic performance of rib fractures in acute blunt trauma

2021 ◽  
Author(s):  
Hui Tan ◽  
Hui Xu ◽  
Nan Yu ◽  
Yong Yu ◽  
Haifeng Duan ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Predictive Value ◽  
Diagnostic Performance ◽  
Reading Time ◽  
Chest Trauma ◽  
Diagnostic System ◽  
Rib Fracture ◽  
Diagnostic Sensitivity ◽  
Reference Standard ◽  
Diagnostic Confidence

Abstract Purpose To evaluate the value of a deep learning-based computer-aided diagnostic system (DL-CAD) in improving the diagnostic performance of acute rib fractures in patients with chest trauma. Methods CT images of 214 patients with acute blunt chest trauma were retrospectively analyzed by two interns and two attending radiologists independently firstly and then with the assistance of a DL-CAD one month later, in a blinded and randomized manner. The consensus diagnosis of fib fracture by another two senior thoracic radiologists was regarded as reference standard. The rib fracture diagnostic sensitivity, specificity, positive predictive value, diagnostic confidence and mean reading time with and without DL-CAD were calculated and compared. Results There were 680 rib fracture lesions confirmed as reference standard among all patients. The diagnostic sensitivity and positive predictive value of interns were significantly improved from (68.82%, 84.50%) to (91.76%, 93.17%) with the assistance of DL-CAD, respectively. Diagnostic sensitivity and positive predictive value of interns assisted by DL-CAD were comparative to those of attendings aided by DL-CAD (94.56%, 86.47%) or not aided (95.67%, 93.83%), respectively. In addition, when radiologists were assisted by DL-CAD, the mean reading time was significantly reduced and diagnostic confidence was significantly enhanced. Conclusions DL-CAD improves the diagnostic performance of acute rib fracture in chest trauma patients, which increases the diagnostic confidence, sensitivity and positive predictive value for radiologists. DC-CAD can advance the diagnostic consistency of radiologists with different experiences.

scholarly journals Unique Metastatic Patterns in Neuroendocrine Neoplasms of Different Primary Origin

2020 ◽  
Author(s):  
B C. M. Hermans ◽  
J de Vos - Geelen ◽  
J L Derks ◽  
L Latten ◽  
I H Liem ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Metastatic Disease ◽  
Reference Network ◽  
Neuroendocrine Neoplasms ◽  
Screening Methods ◽  
Special Focus ◽  
Additional Information ◽  
Netherlands Cancer Registry ◽  
Metastatic Patterns ◽  
Primary Origin

Introduction Neuroendocrine neoplasms (NEN) can originate in different organs, e.g. the gastroenteral tract (GE), pancreas (Pan) or lung (L). Our aim was to examine metastatic patterns for patients with NEN of various primary origins with a special focus on brain metastases to indicate utility for screening. Methods All NEN patients except for small cell lung cancer registered in the Netherlands Cancer Registry from 2008-2018 were selected. Metastatic patterns at initial diagnosis for NEN with different primary origin were compared. In a subcohort of patients from two referral hospitals (2014-2019), additional information on for example development of metastases after initial presentation was available. Results In the nationwide cohort 4,768/11,120 (43%) patients had metastatic disease at diagnosis (GE 1,504/4,710 (32%), Pan 489/1,150 (43%), L 1,230/2,978 (41%)). For GE- and Pan-NEN, the most prevalent metastatic site was the liver (25% and 39%), followed by distant lymph nodes (8% and 8%), whereas only few patients with brain metastases were identified (0% in both). In contrast, for L-NEN, prevalence of metastases in liver (19%), brain (9%), lung (7%) and bone (14%) was more equal. In the reference network cohort, slightly more NEN patients had metastatic disease (260/539, 48%) and similar metastatic patterns were observed. Conclusion Almost half of NEN patients were diagnosed with synchronous metastatic disease. L-NEN have a unique metastatic pattern compared to GE- and Pan-NEN. Remarkably, an important part of L-NEN metastases were in the brain, whereas brain metastases were almost absent in GE- and Pan-NEN, indicating utility of screening in L-NEN.

Production of New and Revised A.A.V.S.O. Charts

1979 ◽  
Vol 46 ◽  
pp. 368
Author(s):  
Clinton B. Ford
Keyword(s):  
Variable Star ◽  
Standard Form ◽  
Original Data ◽  
University Of Pennsylvania ◽  
Standard Format ◽  
Additional Information ◽  
The Gift ◽  
The University

A “new charts program” for the Americal Association of Variable Star Observers was instigated in 1966 via the gift to the Association of the complete variable star observing records, charts, photographs, etc. of the late Prof. Charles P. Olivier of the University of Pennsylvania (USA). Adequate material covering about 60 variables, not previously charted by the AAVSO, was included in this original data, and was suitably charted in reproducible standard format.Since 1966, much additional information has been assembled from other sources, three Catalogs have been issued which list the new or revised charts produced, and which specify how copies of same may be obtained. The latest such Catalog is dated June 1978, and lists 670 different charts covering a total of 611 variables none of which was charted in reproducible standard form previous to 1966.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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