Tomography For Detection Research Articles

Role of Triphasic Computed Tomography for Detection of Hepatitis C Virus Consequences: Review Article

Role of Triphasic Computed Tomography for Detection of Hepatitis C Virus Consequences: Review Article

Single-Photon Emission-Computed Tomography in Detection of Costovertebral Joint Injury after Cervical Spine Surgery: A Case Report

Single-Photon Emission-Computed Tomography in Detection of Costovertebral Joint Injury after Cervical Spine Surgery: A Case Report

Fault Detection Method Based on Improved Faster R-CNN: Take ResNet-50 as an Example

In view of the low accuracy of existing tomographic detection methods, in order to improve the accuracy of tomographic detection, a tomographic detection method based on residual network and Faster R-CNN is proposed. First, input the image into the ResNet-50 feature extraction network to obtain the corresponding feature map, then use the RPN structure to generate the candidate frame, and project the candidate frame generated by the RPN to the feature map to obtain the corresponding feature matrix, and finally, through the ROI pooling layer, each of the feature matrix is scaled to a fixed-size feature map, and then the feature map is flattened through a series of fully connected layers to obtain the prediction result. ResNet-50 mainly solves the problem of network degradation and overfitting caused by deepening of the network layer when extracting the deep features of faults. Faster R-CNN realizes end-to-end training, combines the advantages of ResNet-50 and Faster R-CNN, and has a precise positioning efficiency. The accuracy of detecting faults reaches 90%. The data enhancement is further optimized, the generalization ability of the network is improved, the detection results of the network are optimized, and the accuracy of fault detection is effectively improved, and the feasibility of the method is verified by actual seismic data.

Dual-Mode Volumetric Optoacoustic and Contrast Enhanced Ultrasound Imaging With Spherical Matrix Arrays.

Spherical matrix arrays represent an advantageous tomographic detection geometry for non-invasive deep tissue mapping of vascular networks and oxygenation with volumetric optoacoustic tomography (VOT). Hybridization of VOT with ultrasound (US) imaging remains difficult with this configuration due to the relatively large inter-element pitch of spherical arrays. We suggest a new approach for combining VOT and US contrast-enhanced 3D imaging employing injection of clinically-approved microbubbles. Power Doppler (PD) and US localization imaging were enabled with a sparse US acquisition sequence and model-based inversion based on infimal convolution of total variation (ICTV) regularization. In vitro experiments in tissue-mimicking phantoms and in living mouse brain demonstrate the powerful capabilities of the new dual-mode imaging approach attaining 80 μm spatial resolution and a more than 10 dB signal to noise improvement with respect to a classical delay and sum beamformer. Microbubble localization and tracking allowed for flow velocity mapping up to 40 mm/s.

Role of Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography in Detection of Portal Vein Tumor Thrombosis in Hepatocellular Carcinoma

A 56 year old gentleman with no known comorbidities presented with pain abdomen for 1 month. Triphasic CECT abdomen showed features of cirrhosis with surface irregularities, fissural widening and volume redistribution changes in the liver. Segment VII of liver showed an arterial enhancing lesion measuring 4.2 x 3.5cm showing washout in delayed phase. In view of BCLC A stage with Child Pugh B7, ablation was planned. Before proceeding with ablation, in view of very high alpha-fetoprotein (AFP) level of 9836 ng/mL, he was advised for metastatic evaluation with 18F-FDG PET-CT. The PET scan showed abnormal heterogeneous increased FDG uptake in segment VII of liver (SUV Max 4.7) with arterial enhancement and washout suggestive of metabolically active hepatocellular carcinoma. Also seen was an abnormal linear increased FDG uptake in right branch of portal vein (SUV Max 4.8) which was suggestive of portal vein invasion. In view of portal vein tumor thrombus, ablation procedure was deferred for the patient. Role of PET scan in HCC with vascular invasion is not yet defined. Poor specificity of FDG PET is the major hindrance in establishing PET scan as diagnostic tool for vascular invasion. In small segment invasion when CECT is not able to differentiate between tumour versus bland thrombus PET scan may be significant tool to differentiate between bland thrombus and tumour thrombus. Vascular invasion confirmation have treatment related and prognostic significance. There is a need for a prospective study evaluating the prognostic significance of PET scan based diagnosis of vascular invasion.

Comparison of Ultrasonographic Examination and Computed Tomography in Detection of Incisional Hernia after Transverse Laparotomy

Introduction: Diagnosis of incisional hernias (IHs) should be based on both clinical examination and radiological imaging. Considering increased resolution of the ultrasonographic examination due to the proximity of postoperative scar to the probe, it may be superior to computed tomography for this purpose. The aim of this study was to compare the sensitivity of both modalities in detection of IHs. Method: This prospective observational study included patients after operations for suspected malignancy performed through transverse laparotomy in the Department of General, Transplant and Liver Surgery undergoing strict postoperative follow-up for diagnosis of IHs. The primary end-point was incisional hernia. Patients with discordant results with interval between the two studies of more than -2 weeks for the negative study, as well as those with concordant negative results with the interval >6 months were excluded. Results: Study cohort comprised a total of 15 patients between 2 and 27 months after transverse laparotomy. Of those, 12 patients had IH diagnosed with at least 1 imaging modality. In 10 patients, the diagnosis was made both in ultrasonographic examination and computed tomography. In the remaining two, ultrasonographic examination failed to detect IH diagnosed on computed tomography. There were no cases of IH diagnosed on ultrasonographic examination missed on computed tomography, resulting in 83.3% (10 of 12) sensitivity for ultrasonographic examination and 100% sensitivity for computed tomography. Conclusion: This preliminary study points towards increased accuracy of computed tomography in detection of IH following transverse laparotomy as compared to ultrasonographic examination.

Are angiographic culprit lesions true? Disagreement between angiographic and optical coherence tomographic detection.

Are angiographic culprit lesions true? Disagreement between angiographic and optical coherence tomographic detection.

The evaluation of non-anesthetic computed tomography for detection of pulmonary parenchyma in feline mammary gland carcinoma: a preliminary study

BackgroundThoracic radiography in awake cats is a common procedure for the evaluation of pulmonary metastasis in feline mammary gland carcinoma (MGC). However, due to poor sensitivity, computed tomography (CT) is progressively taking its place. To perform CT in animals, general anesthesia is normally preferred but can cause lung atelectasis, affecting lung interpretation. Besides, MGC is often found in senile cats that are concurrently affected with other diseases, increasing anesthetic risk. Therefore, this study was aimed at comparing the effect of anesthesia on lung atelectasis observed through CT in clinically healthy cats and comparing the feasibility of non-anesthetic CT with non-anesthetic radiography in the detection of lung lesions in feline MGC. Thoracic CTs from anesthetized, clinically healthy cats and non-anesthetized either clinically healthy cats or MGC-affected cats were reviewed. In clinically healthy cats, motion artifacts and characteristics of lung atelectasis were observed and compared. In MGC-affected cats, motion artifacts were observed and compared to clinically healthy cats, and the number of MGC-affected cats, the number and characteristics of lung lesions were compared between non-anesthetic thoracic CT and radiography.ResultsAnesthesia significantly increased lung CT attenuation (P = 0.0047) and was significantly correlated with lung atelectasis (OR = 15; CI 2.02–111.18; P = 0.0081), particularly of the cranial lung lobe. Nonetheless, significantly higher motion artifacts in the caudal thoracic area were found in non-anesthetized healthy cats (P = 0.0146), but comparable low motion artifacts were observed in anesthetized healthy and MGC-affected cats. Non-anesthetic CT revealed higher numbers of MGC-affected cats and pulmonary nodules with a significantly lower nodular diameter (P = 0.0041) than those observed on radiographs. The smallest nodular diameters detected on radiographs and CT were 2.5 and 1.0 mm, respectively. Furthermore, CT showed additional information such as intra-thoracic lymphadenopathy, that could not be seen on radiographs.ConclusionsDespite the motion artifacts, CT without anesthesia is a sensitive technique as it provides better lung inflation. Furthermore, compared to non-anesthetic radiography, non-anesthetic CT provided more information such as higher number of pulmonary nodules of a smaller size, including more distinct intra-thoracic lesions, such as lymphadenopathy, in MGC-affected cats.

Micro-computed Tomography Versus Nano-computed Tomography For Detection Of Fractures After Intravascular Lithotripsy In Heavily Calcified Coronary Lesions

Micro-computed Tomography Versus Nano-computed Tomography For Detection Of Fractures After Intravascular Lithotripsy In Heavily Calcified Coronary Lesions

Deep learning of image- and time-domain data enhances the visibility of structures in optoacoustic tomography.

Images rendered with common optoacoustic system implementations are often afflicted with distortions and poor visibility of structures, hindering reliable image interpretation and quantification of bio-chrome distribution. Among the practical limitations contributing to artifactual reconstructions are insufficient tomographic detection coverage and suboptimal illumination geometry, as well as inability to accurately account for acoustic reflections and speed of sound heterogeneities in the imaged tissues. Here we developed a convolutional neural network (CNN) approach for enhancement of optoacoustic image quality which combines training on both time-resolved signals and tomographic reconstructions. Reference human finger data for training the CNN were recorded using a full-ring array system that provides optimal tomographic coverage around the imaged object. The reconstructions were further refined with a dedicated algorithm that minimizes acoustic reflection artifacts induced by acoustically mismatch structures, such as bones. The combined methodology is shown to outperform other learning-based methods solely operating on image-domain data.

Electrical resistivity tomographic detection of the hidden Thakek fault, Northeast Thailand

ABSTRACTThe Khorat plateau covers most of northeast Thailand along with parts of southern Laos. Recent earthquake hazard assessment and other studies of the regional Thakek fault have rarely appeared in publications and reports. The Thakek fault zone in the Laos region includes three main principal fault planes, but it rapidly fades out when the fault passes through Thailand. A geophysical hidden fault study in the Khorat plateau is herein performed in Bung Kan and Nakhon Phanom provinces, Thailand, where the surface expression is difficult to document through conventional geological surveys. Some fault traces have been identified by satellite image interpretation and digital elevation model analysis. Geological field investigation and electrical resistivity tomography surveys were carried out in order to determine an optimal site for trenching. The electrical resistivity tomography results show zones of high and low resistivity interpreted as coarse sediment layers and mudstone, respectively. The maximum vertical fault offset occurring along the fault trace interpreted from the three‐dimensional electrical resistivity tomographic slices is 40 ± 5 m. Based on the electrical resistivity tomography results, a trench was excavated to directly investigate patterns of faulting and deformation. Based on structural geological observations at the trench wall, indications of faulting have been tentatively identified. In particular, faulting appears to have displaced mudstone over Quaternary sediments with vertical offsets >3.5 m cutting the youngest unit. The result has implications for seismic hazard assessment in northeast Thailand.

Photoacoustic Tomography Image Restoration With Measured Spatially Variant Point Spread Functions.

The spatial resolution of photoacoustic tomography (PAT) can be characterized by the point spread function (PSF) of the imaging system. Due to the tomographic detection geometry, the PAT image degradation model could be generally described by using spatially variant PSFs. Deconvolution of the PAT image with these PSFs could restore image resolution and recover object details. Previous PAT image restoration algorithms assume that the degraded images can be restored by either a single uniform PSF, or some blind estimation of the spatially variant PSFs. In this work, we propose a PAT image restoration method to improve image quality and resolution based on experimentally measured spatially variant PSFs. Using photoacoustic absorbing microspheres, we design a rigorous PSF measurement procedure, and successfully acquire a dense set of spatially variant PSFs for a commercial cross-sectional PAT system. A pixel-wise PSF map is further obtained by employing a multi-Gaussian-based fitting and interpolation algorithm. To perform image restoration, an optimization-based iterative restoration model with two kinds of regularizations is proposed. We perform phantom and in vivo mice imaging experiments to verify the proposed method, and the results show significant image quality and resolution improvement.

Role of computed tomography in detection of mesenteric ischemia

Background: Acute mesenteric ischemia is a life-threatening condition, with a reported mortality rate of 50–90%, that requires early diagnosis and treatment. The present study was conducted to assess small-bowel ischemia using CT scan. Materials & Methods: 60 patients with small-bowel ischemia of both genders underwent CT examinations of the abdomen and pelvis by using 5-mm reconstruction thickness and 5-mm intervals through the abdomen and pelvis. Results: Out of 60 patients, males were 40 and females were 20. Out of 60 patients, 45 (75%) were acute and 15 (25%). Common appearance was pneumatosis in 10 cases, SMA dissection in 12, bowel distention in 18 and bowel wall thickening in 45 patients. The difference was significant (P< 0.05). Conclusion: In patients with acute mesenteric ischemia CT is an effective and efficient diagnostic tool.

Non-contrast and portal venous phase computed tomography in breast cancer hepatic metastases: comparison of tumor measurements and impact on response assessment.

BackgroundFor many common malignancies, including breast cancer, evaluation for metastatic disease using multiphase computed tomography (CT) has fallen out of favor and been replaced by studies performed only in the portal venous phase. However, differences in tumor vascularity could produce differences in appearance on post-contrast imaging.PurposeTo assess non-contrast phase and portal venous phase computed tomography in detection and measurement of hepatic metastases from breast carcinoma.Materials and MethodsA total of 75 CT scans from 52 breast cancer patients were independently assessed by three body imagers for lesion presence, number and size. Readers randomly assessed portal venous phase or combined phase images at one session with cross-over reads performed four to six weeks later.ResultsIn the 58% of cases where index lesions measured larger on combined phase, the mean difference in lesion size was 5.7 mm. In this group, combined phase reads demonstrated an 8.4 mm increase in sum of largest diameters, and a mean percentage sum of largest diameters increase of 19% compared to portal venous phase-only reads.ConclusionAddition of non-contrast phase images results in increased index lesion size in most patients with hepatic metastases from breast cancer. If only the portal venous phase is utilized, there is potential for incorrectly diagnosing disease progression on follow-up due to underestimation of lesion size.

Diagnostic accuracy of contrast enhanced computed tomography (CECT) in detection of necrosis in acute pancreatitis by taking surgical findings as gold standard.

To determine the diagnostic accuracy of contrast-enhanced computed tomography in the detection of necrosis in acute pancreatitis by taking surgical findings as the gold standard. The descriptive cross-sectional study was conducted at Radiology and Surgery departments of the Jinnah Postgraduate Medical Centre, Karachi, from January 1 to June 30, 2016, and comprised patients of either gender having severe clinical pancreatitis with symptoms lasting >72 hours without showing improvement. Computed tomography scan was performed with slice thickness of 3mm. Multiple detector scan of abdomen with contrast was done. Data was analysed using SPSS 19. Of the 191 patients, 97 (50.8%) were female, and 129 (67.50%) were aged >40 years, with an overall mean age of 39.65±11.67 years. Mean duration of the symptoms was 85.61±6.41 hours. Contrast-enhanced computed tomography scan's sensitivity was 71.4%, specificity 87%, positive predictive value 83.33%, negative predictive value 76.99% and over all diagnostic accuracy was 79.5%. The diagnostic accuracy of contrast-enhanced computed tomography was found to be high in detecting necrosis in acute pancreatitis cases.

A rare case of severe pulmonary embolism revealed by consciousness disorders

Over the several years, only few cases of consciousness was diagnosed as pulmonary embolism in the world. The obstruction of the pulmonary arterial tree is viewed as the source of pulmonary embolism, and eventually trigger the severe cardiopulmonary failure. Diagnosis of pulmonary embolism is dependent on the imaging data, such as the computed tomographic detection. Above 50% of patients with pulmonary embolism are normotensive and they have neither echocardiographic nor laboratory signs of right heart dysfunction. Therefore, the precise prognosis of acute pulmonary embolism presented with rare characteristic is important to improve risk management. In some circumstance, the diagnosis of pulmonary embolism remains a challenge with atypical characterization presented in this case. A case report of this is given to accumulate the diagnostic experience for further analysis. Herein, we report a case of a severe pulmonary embolism that revealed by consciousness disorders. This report highlights the extracorporeal membrane oxygenation (ECMO) could be the only life-sustaining and the possibility of the solution treatment of acute pulmonary embolism.

Role of Unenhanced Multi-Detector Computed Tomography in Detection of Urinary Calculi in Comparison with Ultrasonography

Introduction Urinary calculi are solid deposits found in the urinary tract from minerals dissolved in the urine.1 Calculi located in the kidneys, ureters, urinary bladder or urethra and are one of the major diseases that have affected people since ancient times.2 The prevalence of urinary tract c

Detection of debonding in reinforced concrete beams using ultrasonic transmission tomography and hybrid ray tracing technique

This paper concerns inspection of reinforced concrete elements, with particular emphasis on assessing the quality of the adhesive connection between steel and concrete. A novel theoretical model was developed to determine the paths of transmitted, refracted and reflected elastic waves as well as a creeping wave propagated along the inclusion surface. Imaging the internal structure of tested beams was based on wave propagation measurements carried out on their surface and computed tomography. The ray tracing was performed by the hybrid approach as a combination of the network theory and the ray bending methods. The obtained results indicated a great potential of ultrasonic tomography in detection of debonding in reinforced concrete structures.

Improvement of diagnostic accuracy of 18fluorine-fluorodeoxyglucose PET/computed tomography in detection of infective endocarditis using a 72-h low carbs protocol.

The major challenge in diagnosing infective endocarditis using fluorine-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) is the high physiological myocardial F-FDG uptake, which may interfere with the detection of pathological uptake. Our aim was to retrospectively analyse the impact of a low-carbohydrate, high-protein, high-fat (LCHPHF) diet starting 72 h before the examination with classic overnight fasting. We included 92 patients (51 with LCHPHF diet 72 h before the examination and 41 with overnight fast only). Left ventricular (LV) myocardial F-FDG uptake was visually evaluated, to estimate the effect of LCHPHF on myocardial F-FDG uptake, we used a three-point visual scale: 0, negligible uptake and evaluable examination; 1, mild uptake and doubtful examination and 2, intense uptake and not evaluable examination. SUVmax and SUVmean were calculated putting a region of interest on LV myocardium at the level of the largest cardiac footprint and on the site of suspected lesion. Thus, a ratio between SUV of the suspect lesion and SUV of LV was calculated as SUV ratio. By visual assessment, in LCHPHF diet group 46 patients (96.1%) had score 0, 3 patients (5.9%) had score 1 and nobody had score 2. In control group, 23 patients (56.1%) had a score 2, 12 (29.3%) patients obtained a score 1 with a doubtful examination and 6 patients (14.6%) were classified with a score 0 with reportable examination. We demonstrated that an LCHPHF diet can adequately suppress the physiological myocardial uptake leading to a significant improvement in the interpretability and diagnostic accuracy of F-FDG PET/CT in infective endocarditis.

Quantum teleportation of single-electron states

We consider a scheme for on-demand teleportation of a dual-rail electron qubit state, based on single-electron sources and detectors. The scheme has a maximal efficiency of 25%, which is limited both by the shared entangled state as well as the Bell-state measurement. We consider two experimental implementations, realizable with current technology. The first relies on surface acoustic waves, where all the ingredients are readily available. The second is based on Lorentzian voltage pulses in quantum Hall edge channels. As single-electron detection is not yet experimentally established in these systems, we consider a tomographic detection of teleportation using current correlators up to (and including) third order. For both implementations we take into account environmental effects.