scholarly journals Non-contrast MR portography using time-spatial labeling inversion pulse for diagnosis of portal vein pathology

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Amr Ahmed Mubarak ◽  
Ghada Elsaed Awad ◽  
Mohamed Adel Eltomey ◽  
Mahmoud Abd Elaziz Dawoud
Keyword(s):  
Image Quality ◽  
Portal Vein ◽  
Imaging Modality ◽  
Inversion Pulse ◽  
Pulse Technique ◽  
Portal Phase ◽  
Pathological Conditions ◽  
Color Duplex Ultrasonography ◽  
Phase Images ◽  
History Of

Abstract Background To study the ability of non-contrast MR portography using time-spatial labeling inversion pulse (T-SLIP) as a non-invasive contrast-free imaging modality to delineate different portal vein pathological conditions. The study included 25 patients with known history of portal vein disease and another 25 age-matched patients with normal portal vein. Both groups were examined by respiratory-triggered non-contrast MR portography using time-spatial labeling inversion pulse technique. Image quality was assessed first, and findings of diagnostic scans were compared to color duplex ultrasonography and selectively in those with diseased portal vein to portal-phase images of dynamic contrast-enhanced MRI. Results Significant relation was found between breathing regularity and image quality in T-SLIP sequence, with diagnostic scans sensitivity and specificity of 89.29% and 86.21%, respectively, for diagnosis of different portal vein pathological conditions. Conclusions Non-contrast MR portography is a useful technique for diagnosis of portal vein pathology in carefully selected patients.

scholarly journals Dual Energy on Dual Source CT in Abdominal Imaging

2020 ◽  
Author(s):  
Varchetta Francesco ◽  
Orlando Giuseppe ◽  
Laurenza Francesco ◽  
Rengo Alessandro ◽  
Danzi Roberta ◽  
...  
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Absorbed Dose ◽  
Dual Energy ◽  
Data Sets ◽  
Diagnostic Quality ◽  
Portal Phase ◽  
Phase Images ◽  
Dual Source ◽  
The Difference

Establish whether virtual non-contrast images can replace real non-contrast images, avoiding the preliminary scan, thus saving the patient dose. Forty-one patients were studied on a second-generation dual-source scanner, triphasic were applied on all patients, arterial and venous phase was acquired in dual-energy. HU values of TNC and VNC scans were compared through ROI on liver, spleen, kidneys, aorta, muscle, and fat. Qualitative analysis of the data sets was performed by four readers and the values from 1 to 4 (1. poor, 2. fair, 3. good, 4. excellent.) were assigned to define the diagnostic quality of the images. Then the absorbed dose ratios between the virtual images and the pre-contrast and portal phase images were compared. HU values were analyzed with the t-test and the difference was statistically significant P<0.0001. Image quality was evaluated as excellent or good in 91,3% of TNC and 81,6% of VNC. At last, VNC showed a sensitive dose reduction -46% compared to conventional triphasic protocol. Overall VNC has shown a good image quality comparable to TNC. The dose reduction obtained from the extraction of images without iodine, avoiding further scans, suggests the use of the dual-energy protocol in many exams.

scholarly journals Value of preoperative computed tomography for meso-Rex bypass in children with extrahepatic portal vein obstruction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huiying Wu ◽  
Ning Zhou ◽  
Lianwei Lu ◽  
Xiwen Chen ◽  
Tao Liu ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Portal Vein ◽  
Predictive Value ◽  
Extrahepatic Portal Vein Obstruction ◽  
Portal Vein Obstruction ◽  
Left Portal Vein ◽  
History Of ◽  
Associated Malformations ◽  
Sensitivity Specificity

Abstract Background Extrahepatic portal vein obstruction (EHPVO) is the most important cause of hematemesis in children. Intrahepatic left portal vein and superior mesenteric vein anastomosis, also known as meso-Rex bypass (MRB), is becoming the gold standard treatment for EHPVO. We analyzed the value of preoperative computed tomography (CT) in determining whether MRB is feasible in children with EHPVO. Results We retrieved data on 76 children with EHPVO (50 male, 26 female; median age, 5.9 years) who underwent MRB (n = 68) or the Warren procedure (n = 8) from 2013 to 2019 and retrospectively analyzed their clinical and CT characteristics. The Rex recess was categorized into four subtypes (types 1–4) depending on its diameter in CT images. Of all 76 children, 7.9% had a history of umbilical catheterization and 1.3% had leukemia. Sixteen patients (20 lesions) had associated malformations. A total of 72.4% of Rex recesses could be measured by CT, and their mean diameter was 3.5 ± 1.8 mm (range 0.6–10.5 mm). A type 1, 2, 3, and 4 Rex recess was present in 9.2%, 53.9%, 11.8%, and 25.0% of patients, respectively. MRB could be performed in patients with types 1, 2, and 3, but those with type 4 required further evaluation. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of CT were 100%, 83.8%, 42.1%, 100%, and 85.5%, respectively. Conclusions Among the four types of Rex recesses on CT angiography, types 1–3 allow for the performance of MRB.

scholarly journals A comparative study of multi-detector CT portography versus endoscopy in evaluation of gastro-esophageal varices in portal hypertension patients

2020 ◽  
Vol 51 (1) ◽  
Author(s):  
Hany El-Assaly ◽  
Lamiaa I. A. Metwally ◽  
Heba Azzam ◽  
Mohamed Ibrahim Seif-Elnasr
Keyword(s):  
Portal Hypertension ◽  
Portal Vein ◽  
Esophageal Varices ◽  
Imaging Modality ◽  
Splenic Vein ◽  
Gastric Varices ◽  
Gi Endoscopy ◽  
Upper Gi ◽  
Upper Gi Endoscopy ◽  
Vein Diameter

Abstract Background Portal hypertension is a major complication resulting from obstruction of portal blood flow, like cirrhosis or portal vein thrombosis, that leads to portal hypertension. MDCT angiography has become an important tool for investigation of the liver as well as potentially challenging varices by detailing the course of these tortuous vessels. This information is decisive for liver transplantation as well as for common procedures in which an unexpected varix can cause significant bleeding. Results This study included an assessment of 60 cases of portal hypertension (28 males and 32 females), their age ranged from 42 to 69 years (mean age = 57.2 ± 6.63). All patients were diagnosed with portal hypertension, underwent upper GI endoscopy followed by a triphasic CT scan with CT angiographic assessment for the screening of gastro-esophageal varices. CT is highly sensitive as compared to upper GI endoscopy (sensitivity 93%) in detecting esophageal varices. Gastric varices detected by CT in 22 patients (37%) compared to 14 patients (23%) detected by endoscopy. While paraesophageal varices were detected in 63% of patients and retro-gastric varices in 80% of patients that were not visualized by endoscopy. Our study reported that the commonest type of collaterals were the splenic collaterals, and we also found there is a significant correlation between the portal vein diameter and the number of collaterals as well as between the portal vein diameter and splenic vein diameter. Conclusions Multi-slice CT serves as an important non-invasive imaging modality in the diagnosis of collaterals in cases of portal hypertension. CT portography can replace endoscopy in the detection of high-risk varices. It also proved that there is a correlation between portal vein diameter, splenic vein diameter, and number of collaterals.

scholarly journals Estimation of contrast-to-noise ratio in CT and CBCT images with varying scan settings in presence of different implant materials

2019 ◽  
Vol 48 (8) ◽  
pp. 20190139
Author(s):  
Emine Şebnem Kursun-Cakmak ◽  
Husniye Demirturk Kocasarac ◽  
Seval Bayrak ◽  
Gülbahar Ustaoğlu ◽  
Marcel Noujeim
Keyword(s):  
Image Quality ◽  
Imaging Modality ◽  
Cone Beam Ct ◽  
Medical Systems ◽  
Plastic Container ◽  
Implant Materials ◽  
Different Types ◽  
Noise Ratio ◽  
Titanium Grade ◽  
Imagej Software

Objectives: To assess the contrast-to-noise ratio (CNR) of four different types of dental implant materials in CT and cone beam CT (CBCT) images with varying scan settings. Methods: Four different types of implants: zirconium (Zr), titanium (Ti) Grade 4 and 5 and titanium–zirconium (Ti–ZrO2) alloy were placed in a 3% gelatin phantom in a cylindrical plastic container and scanned with two different CT machines (GE Medical systems and Toshiba Medical Systems) and one CBCT machine (I-CAT, Imaging Sciences International) with different voxel sizes of 0.2, 0.25, 0.3 and 0.4 mm. Images were analyzed using ImageJ software with the purpose of estimating the CNR. Results: The CNR obtained from images acquired with CT was lower than the CBCT with all voxel sizes tested. 0.3 and 0.4 mm voxel sizes exhibited the highest CNR (p < 0.05) that gives the best image quality. Among the implant materials tested, titanium Grade 5 has the highest levels of CNR while Zirconium has the lowest (p < 0.05). Conclusions: The optimum protocol for radiographic follow-up in areas near implants on the I-CAT is low-resolution settings (0.3 and 0.4 mm voxel sizes) which gave the highest CNR thus image quality. In presence of Zr implants, an alternative imaging modality (i.e., MRI) may be considered to avoid low-quality images.

scholarly journals CT Simplified Radiomic Approach to Assess the Metastatic Ductal Adenocarcinoma of the Pancreas

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1843
Author(s):  
Mirko D’Onofrio ◽  
Riccardo De Robertis ◽  
Gregorio Aluffi ◽  
Camilla Cadore ◽  
Alessandro Beleù ◽  
...  
Keyword(s):  
Pancreatic Ductal Adenocarcinoma ◽  
Ductal Adenocarcinoma ◽  
Newly Diagnosed ◽  
Inclusion Criteria ◽  
Permeability Index ◽  
Metastatic Tumors ◽  
Qualitative And Quantitative ◽  
Portal Phase ◽  
Phase Images ◽  
Adenocarcinoma Of The Pancreas

The aim of this study was to perform a simplified radiomic analysis of pancreatic ductal adenocarcinoma based on qualitative and quantitative tumor features and to compare the results between metastatic and non-metastatic patients. A search of our radiological, surgical, and pathological databases identified 1218 patients with a newly diagnosed pancreatic ductal adenocarcinoma who were referred to our Institution between January 2014 and December 2018. Computed Tomography (CT) examinations were reviewed analyzing qualitative and quantitative features. Two hundred eighty-eight patients fulfilled the inclusion criteria and were included in this study. Overall, metastases were present at diagnosis in 86/288 patients, while no metastases were identified in 202/288 patients. Ill-defined margins and a hypodense appearance on portal-phase images were significantly more common among patients with metastases compared to non-metastatic patients (p < 0.05). Metastatic tumors showed a significantly larger size and significantly lower arterial index, perfusion index, and permeability index compared to non-metastatic tumors (p < 0.05). In the management of pancreatic ductal adenocarcinoma, early detection and correct staging are key elements. The study of computerized tomography characteristics of pancreatic ductal adenocarcinoma showed substantial differences, both qualitative and quantitative, between metastatic and non-metastatic disease.

scholarly journals Metal artifacts in intraoperative O-arm CBCT scans

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Juha I. Peltonen ◽  
Touko Kaasalainen ◽  
Mika Kortesniemi
Keyword(s):  
Image Quality ◽  
Imaging Modality ◽  
Nonlinear Effects ◽  
Exposure Level ◽  
Metal Artifacts ◽  
Imaging Protocol ◽  
Metal Implants ◽  
Comprehensive Determination

Abstract Background Cone-beam computed tomography (CBCT) has become an increasingly important medical imaging modality in orthopedic operating rooms. Metal implants and related image artifacts create challenges for image quality optimization in CBCT. The purpose of this study was to develop a robust and quantitative method for the comprehensive determination of metal artifacts in novel CBCT applications. Methods The image quality of an O-arm CBCT device was assessed with an anthropomorphic pelvis phantom in the presence of metal implants. Three different kilovoltage and two different exposure settings were used to scan the phantom both with and without the presence of metal rods. Results The amount of metal artifact was related to the applied CBCT imaging protocol parameters. The size of the artifact was moderate with all imaging settings. The highest applied kilovoltage and exposure level distinctly increased artifact severity. Conclusions The developed method offers a practical and robust way to quantify metal artifacts in CBCT. Changes in imaging parameters may have nonlinear effects on image quality which are not anticipated based on physics.

scholarly journals Correlation of image quality parameters with tube voltage in X-ray dark-field chest radiography: a phantom study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas P. Sauter ◽  
Jana Andrejewski ◽  
Manuela Frank ◽  
Konstantin Willer ◽  
Julia Herzen ◽  
...  
Keyword(s):  
Image Quality ◽  
Imaging Modality ◽  
Signal Strength ◽  
Dark Field ◽  
Tube Voltage ◽  
X Ray ◽  
Dose Area Product ◽  
Dark Field Imaging ◽  
Field Imaging

AbstractGrating-based X-ray dark-field imaging is a novel imaging modality with enormous technical progress during the last years. It enables the detection of microstructure impairment as in the healthy lung a strong dark-field signal is present due to the high number of air-tissue interfaces. Using the experience from setups for animal imaging, first studies with a human cadaver could be performed recently. Subsequently, the first dark-field scanner for in-vivo chest imaging of humans was developed. In the current study, the optimal tube voltage for dark-field radiography of the thorax in this setup was examined using an anthropomorphic chest phantom. Tube voltages of 50–125 kVp were used while maintaining a constant dose-area-product. The resulting dark-field and attenuation radiographs were evaluated in a reader study as well as objectively in terms of contrast-to-noise ratio and signal strength. We found that the optimum tube voltage for dark-field imaging is 70 kVp as here the most favorable combination of image quality, signal strength, and sharpness is present. At this voltage, a high image quality was perceived in the reader study also for attenuation radiographs, which should be sufficient for routine imaging. The results of this study are fundamental for upcoming patient studies with living humans.

scholarly journals Introducing a frequency-tunable magnetic particle spectrometer

2015 ◽  
Vol 1 (1) ◽  
pp. 249-253 ◽  
Author(s):  
André Behrends ◽  
Matthias Graeser ◽  
Thorsten M. Buzug
Keyword(s):  
Magnetic Nanoparticles ◽  
Image Quality ◽  
Magnetic Particle ◽  
Imaging Modality ◽  
Magnetic Particle Imaging ◽  
Common Technique ◽  
Frequency Tunable ◽  
Excitation Frequencies ◽  
Particle Imaging

AbstractImage quality in the new imaging modality magnetic particle imaging (MPI) heavily relies on the quality of the magnetic nanoparticles in use. Therefore, it is crucial to understand the behaviour of such particles. A common technique to analyze the behaviour of the particles is magnetic particle spectrometry (MPS). However, most spectrometers are limited to measurements at a single or multiple discrete excitation frequencies. This paper introduces a frequency-tunable spectrometer, able to perform measurements in the range of 100 Hz - 24kHz.

scholarly journals Repeated Plastic Stentings of Common Hepatic Duct for Portal Vein Aneurysm Compression in a Patient Unsuitable for Surgery

2018 ◽  
Vol 12 (3) ◽  
pp. 570-577 ◽  
Author(s):  
Jeffrey Sun ◽  
Cheuk-Kwan Sun ◽  
Cheuk-Kay Sun
Keyword(s):  
Portal Vein ◽  
Surgical Intervention ◽  
Vascular Malformations ◽  
Imaging Modality ◽  
Hepatic Duct ◽  
Therapeutic Option ◽  
Clinical Signs ◽  
Common Hepatic Duct ◽  
Low Grade ◽  
Portal Vein Aneurysm

Portal vein aneurysms are rare vascular malformations with unclear etiologies and optimal treatment guidelines. Although Doppler ultrasonography is the most commonly used diagnostic tool, there is no gold standard imaging modality. Despite recommendations of surgical treatment for symptomatic aneurysms, there are limited options in the management of portal vein aneurysm-related complications in patients unfit for surgical intervention. We describe an 85-year-old man who presented with abdominal pain and low-grade fever with clinical signs consistent with cholangitis. Endoscopic retrograde cholangiopancreatography revealed a common hepatic duct stricture and concomitant intraductal ultrasonography identified adjacent aneurysmal portal vein dilatation. The final diagnosis of portal vein aneurysm was made using contrast computerized tomography scan. The patient was considered unsuitable for surgery due to his advanced age and multiple comorbidities. Instead, an endoscopic biliary plastic stent was inserted as a therapeutic alternative, which successfully achieved complete resolution of symptoms 3 days after the procedure. The patient was regularly followed at the outpatient clinic with repeated stent replacements every 3 to 4 months. After a follow-up of over 3.5 years, the patient remained symptom-free without signs of portal vein aneurysm compression. The result suggests that repeated stent replacements may be a therapeutic option for biliary compression by portal vein aneurysm in patients contraindicated for surgical intervention.

scholarly journals Source reconstruction for bioluminescence tomography via L1∕2 regularization

2018 ◽  
Vol 11 (02) ◽  
pp. 1750014 ◽  
Author(s):  
Jingjing Yu ◽  
Qiyue Li ◽  
Haiyu Wang
Keyword(s):  
Image Quality ◽  
Matching Pursuit ◽  
Imaging Modality ◽  
Reconstruction Algorithm ◽  
Reconstruction Method ◽  
Reconstruction Algorithms ◽  
Preclinical Research ◽  
Bioluminescence Tomography ◽  
Comparison Results ◽  
Stable Reconstruction

Bioluminescence tomography (BLT) is an important noninvasive optical molecular imaging modality in preclinical research. To improve the image quality, reconstruction algorithms have to deal with the inherent ill-posedness of BLT inverse problem. The sparse characteristic of bioluminescent sources in spatial distribution has been widely explored in BLT and many L1-regularized methods have been investigated due to the sparsity-inducing properties of L1 norm. In this paper, we present a reconstruction method based on L[Formula: see text] regularization to enhance sparsity of BLT solution and solve the nonconvex L[Formula: see text] norm problem by converting it to a series of weighted L1 homotopy minimization problems with iteratively updated weights. To assess the performance of the proposed reconstruction algorithm, simulations on a heterogeneous mouse model are designed to compare it with three representative sparse reconstruction algorithms, including the weighted interior-point, L1 homotopy, and the Stagewise Orthogonal Matching Pursuit algorithm. Simulation results show that the proposed method yield stable reconstruction results under different noise levels. Quantitative comparison results demonstrate that the proposed algorithm outperforms the competitor algorithms in location accuracy, multiple-source resolving and image quality.

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