Multislice Helical CT Research Articles

Multislice helical computed tomography imaging diagnosis and surgical treatment of primary tracheal tumor in cardiothoracic surgery.

it aimed to explore the value of multislice helical computed tomography (MSCT) in the diagnosis and surgical treatment of primary tracheal tumors. 64 patients with the primary tracheal tumor who were diagnosed in Wuxi Second People's Hospital from March 2020 to March 2021 were selected as the research objects. MSCT imaging was performed on all patients, and suitable surgical methods. The pathological results were compared with original CT, CT virtual endoscopy (CTVE), and Comparisons were made using CT three-dimensional reconstruction images to evaluate the accuracy of MSCT diagnosis. Parameters such as postoperative complications and survival rates were observed to assess surgical effectiveness and safety. Compared with original CT images (70%, 72%, 70%), the diagnostic accuracy of VR images (80%, 80%, 80%), MPVR images (85%, 90%, 92%), and CTVE images (100%, 100%, 100%) was remarkably improved (P<0.05). The three-year survival rate of patients with smooth muscle tumors, malignant tumors, salivary gland adenoma, papillary tumors, and inflammatory polyp was markedly lower than that of the one-year survival rate, with a significant difference (P<0.05). The incidence of postoperative complications was 14.1%, with three cases resulting in complication-related deaths. the diagnostic accuracy of MSCT imaging of primary tracheal tumor was high. The diagnostic accuracy of CTVE was higher than that of VR and MPVR. Besides, surgical treatment of primary tracheal tumor had a substantial effect, with no serious postoperative complications.

Computed tomographic evaluation of the distal limb in the standing sedated horse: Technique, imaging diagnoses, feasibility, and artifacts.

In several veterinary institutions, adjustments of CT machines have been made that allow for imaging of the standing horse. The risk of general anesthesia is eliminated and the shorter scan completion time reduces cost to clients. The objective of this retrospective, analytical study was to evaluate the technique, imaging diagnoses, feasibility, and image artifacts of multi-slice helical CT of horses' distal limbs acquired under standing sedation. The CT images of 250 horses of various breeds, aged 3-23 years, that underwent standing distal limb CT were evaluated. Three observers assessed the CT images for artifacts and inter-observer agreement was calculated. Eighty-six percent (95% confidence interval (CI), 81-90) of the scans were carried out on the forelimbs, while 14% (95% CI, 10-19) were of the hindlimbs. A total of 65% (95% CI, 59-71) of horses that underwent standing sedated CT had single imaging diagnoses. Seventy-one percent (95% CI, 65-77) of the cases had unilateral lesions, 27% (95% CI, 22-33) had bilateral lesions and 2% (95% CI, 1-4) had no diagnosed lesions. The average CT acquisition time was 17.5 minutes (range=15-20). The average number of acquisitions per horse was 1.7 (median=1; range=1-4). There was good to excellent agreement between all three observers for the presence of motion artifact in the metacarpo/metatarsophalangeal joints, identification of marked beam hardening artifact, mild solar/ skin dirt, and photon starvation artifact (kappa 0.61-0.80). No complications were encountered. Standing examination of the distal limb achieved diagnostic image quality that was obtained with minimal acquisition attempts and in a timely manner.

Safety and Effectiveness of Medical Therapy and Surgical Intervention for Renal Angiomyolipoma Associated With Tuberous Sclerosis Complex.

Our study aimed to evaluate the effect of daily oral dose of everolimus in the treatment of patients with tuberous sclerosis complex (TSC) associated with renal angiomyolipoma (RAML), and the feasibility and safety of surgical treatment approach. We retrospectively investigated a total of 13 patients diagnosed of TSC-associated renal angiomyolipoma (TSC-RAML) who were scheduled for everolimus therapy. At 3-9 months after starting everolimus therapy, 4 of the study patients were symptomatic and underwent partial renal resection surgery. Two of these surgeries were performed open nephron sparing surgery (NSS) after TAE (Trans-arterial embolization), while the remaining 2 underwent robot-assisted partial nephrectomy (RAPN). A multi-slice helical CT scan performed among all the patients every 3months, which was used to measure the volume and the density of the lesion. Follow-up CT images revealed a significant reduction (P < .05) in the RAML volume, at a rate ranging from 11.6 to 42.5%, in response to everolimus therapy (10mg/day) in TSC-RAML patients. Further, a significant decrease in the mean tumor density (P < .05), as compared to its baseline value, was also observed. Super-selective renal arterial embolization done prior to NSS was effective in reducing the intraoperative bleeding and stabilizing the patient during the NSS procedure: mean warm ischemia time was 29.5minutes (range 18-40minutes) and mean intraoperative bleeding volume was 275mL (range 200-350mL). Post-surgical (both NSS and RAPN) follow-up showed a favorable perioperative morbidity profile with good renal functional preservation. At the end of 2years, all patients were well, with no signs of progression or recurrence of the condition, and demonstrated normal renal function. The results suggested oral everolimus as an effective non-invasive therapy to treat TSC-RAML patients. Post mTOR inhibitor therapy, NSS and RAPN are preferred mode of surgical intervention in symptomatic patients. TAE prior to NSS is beneficial.

Fetal organ dose assessment during pelvic CT examination using Monte Carlo/GATE simulation and pregnancy voxelized phantom Katja

In certain situations where there is a risk of fetal-pelvis disproportion (risk that the baby will not be able to pass through the pelvis), pelvic scan examination may be prescribed to the mother at the end of pregnancy. This examination assesses the dimensions of the pelvis by measuring various bone diameters. It also provides details information about pelvis morphology. Patients are routinely worried about the risk of unwanted effects on the fetus from radiation exposure. Accepting the possibility of adverse effects from fetal exposure and the inability to measure directly in vivo [1]. Medical physicists have developed several techniques to determine the amount of radiation that reaches the fetus. Physicians need to understand these methods and how the numbers they produce relate to possible biological effects on the fetus. In this study A 16 helical multi-slice CT scanner was simulated. Full technical specifications were obtained from the constructor and simulated in GATE to produce single x-ray beams. Katja voxelized patient phantom, pregnant in 24 weeks, was scanned with pelvis protocol. The code was used to estimate the absorbed and effective doses in the important organs of the fetus as a consequence of the scanning parameters. The purpose of this study was to use patient voxelized phantom Katja to assessed fetal organ dose, effective dose and evaluate the risk related to radiation due to pelvis CT examination using Monte Carlo/Gate platform. Fetal effective doses were 4.8, 6.3 and 8.2 mSv for 80, 110 and 130 kV respectively. Fetal dose in heart, eye lens, brain was 1.61, 1.6 and 0.8 mGy for 80 kV. Since the dose to the fetus from a pelvic scan is lower than 50 mGy, when exposed to a single scan teratogenic effects on the fetus are not significant concern [2].

Ектопічний синдром Кушинга: АКТГ-продукуючий карциноїд легені. Випадок із практики

Наведено опис клінічного випадку ектопічного синдрому Кушинга у чоловіка 39 років. Характерні ознаки гіперкортицизму (ожиріння, артеріальна гіпертензія, стрії, витончення кінцівок, міастенія, цукровий діабет, гіпокаліємія) розвивалися протягом 1,5 року. Однак діагноз синдрому Кушинга був виставлений після госпіталізації з приводу артеріальної гіпертензії. Гормони: адренокортикотропний гормон (АКТГ) — 110 пг/мл (норма — 7–69), добова екскреція кортизолу з сечею — 3400 мкг/добу (норма — 28,5–213,7). Магнітно-резонансна томографія гіпофіза, мультизрізова спіральна комп’ютерна томографія (МСКТ) органів черевної порожнини і сканування з 111In-октреотидом пухлини не виявили. Тільки після МСКТ органів грудної клітки був виявлений карциноїд лівої легені. Хворий був прооперований, після чого протягом двох місяців практично видужав. Патогістологічний висновок: високодиференційована нейроендокринна пухлина. Рівень експресії в клітинах цитоплазматичних маркерів нейроендокринного диференціювання: синаптофізин (+), хромогранін А (+), СD56 (–), CD68 (–). Індекс проліферації Ki 67 становив 1 %. Гормони: АКТГ крові — 34 пг/мл, кортизол крові — 13,69 мкг/дл (норма — 6,2–19).

Role Of Positron Emission Tomography/Computed Tomography In The Initial Staging And Evaluation Of The Therapeutic Response In Patients With Non-Hodgkin Lymphoma

Background: Malignant lymphoma is the most common hematological malignancy accounts for approximately 8% of all adult malignancies. The aim of this work is to study the role of PET/CT in the diagnosis and follow up of Non-hodgkin lymphoma. Methods: The study was conducted on eighty patients where the diagnosis of non-hodgkin lymphoma have been pathologically confirmed, 50 males (62.5%) and 30 females (37.5%), their ages are ranged between 14 to 81 years old. All patients were examined using Siemens Bio-graph true point PET/CT scanner. These dedicated systems integrate a PET scanner with a multi-slice helical CT scanners permit the acquisition of co-registered CT and PET images in one session. Results: among the 40 patients referred for follow up assessment, their SUVmax of the initial PET/CT examination ranged from 3 – 49.0 with a mean value of 17.05 ± 11.86 SD, with a significant change (p ≤ 0.046) in their follow up examination with SUVmax ranged from 0.0 – 28.0 with a mean value of 11.73 ± 9.25 SD, There were statically significant difference between (PET/CT) staging and CECT scan staging (p < 0.001). Conclusion: PET/CT proved statistically to be more efficient in follow up studies after chemotherapy using the standard uptake value (SUV) being more related to the functional activity of the residual tumor cells rather than to the size of the tumor itself.

The Effects of Multi-Slice Helical Computed Tomography and Phlebography on Edema Regression Nursing of Lower Limbs Varicosis

Objective: To explore the effects of multi-slice helical computed tomography (MSCT) and phlebography on edema regression nursing of lower limbs varicosis, and to analyze the values of MSCT and phlebography on the diagnosis and treatment of lower limb varicosis. Methods: A total of 193 patients with lower limb varicosis treated in the Vascular Surgery Department were included as the research objects. According to different examination methods, the included patients were divided into the MSCT group, and the MSCT combined with the phlebography group, Then, patients in both groups received joint treatment of high ligation and varicectomy. The Gabor filtering-based algorithm and the Mean-Variance Efficient Frontier (MVEF) algorithm were used to smoothen the obtained images. Also, the operation rates and contradiction compositions of patients in both groups were analyzed. Patients who received surgical treatment were followed up for three months to one year; whether the deep vein thrombosis (DVT) occurred in them were observed, as well as the edema regression. Results: As for gender, grading, disease history, duration of disease, and onset age of both groups, no statistical significance was found (P &gt; 0.05). Compared to group A, the positive detection rate of postoperative DVT was lower in group B, so did the operation rate. In group A, 32 cases of edema regressed significantly, and the disease condition was relieved. In group B, 35 cases of edema were regressed. Conclusion: Compared with MSCT, phlebography had a higher screening rate for indications of lower limb varicosis, which could effectively reduce the probability of DVT after operations and relieve the symptoms of edema in patients. In addition, although the sensitivity of MSCT was relatively low, it could be used for the primary screening diagnosis of lower limb varicosis.

The Imaging Performances of Contrast-Enhanced Ultrasound, Computed Tomography, and Magnetic Resonance Imaging for Extrahepatic Cholangiocarcinoma

Objective: To compare the imaging performances of contrast-enhanced ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), thereby explore their values and significances in clinical practices of diagnosing extrahepatic cholangiocarcinoma. Methods: A total of 56 patients with extrahepatic cholangiocarcinoma were included as research objects. All the patients underwent contrast-enhanced ultrasound examination, enhanced MRI examination, and multi-slice helical CT (MSCT) examination. The major contents of analysis and observation included the location of the lesion, the range, the features of blood flow signal, the echoes of lesions at various phases, the enhancement levels, and the morphology. Then, the tabu search algorithm was applied to reconstruct the images, thereby completing the construction of the image objective function. Results: In terms of histopathological typing, 9 papillary adenocarcinomas, 22 invasive adenocarcinomas, and 25 poorly-to-moderate differentiated adenocarcinomas were found. In terms of ultrasound results, 27 lesions were isoechoic, 23 lesions were hypoechoic, and 6 lesions were hyperechoic. In terms of MRI results, 66% of the patients had hyperechoic lesions during the arterial phase, and 55.1% of the patients had isoechoic lesions during the portal phase. During the delay phase, 30.3% of the patients had isoechoic lesions, and 58.9% of the patients had hyperechoic lesions. Conclusion: Contrast-enhanced ultrasound, CT, and MRI had magnificent values and significance in the clinical diagnosis of extrahepatic cholangiocarcinoma, which could be widely applied in the diagnosis and treatment of extrahepatic cholangiocarcinoma. In addition, the contrast-enhanced ultrasound and CT could be used as an effective supplementary basis for enhanced MRI diagnosis. These three diagnostic methods had respective advantages and could be used in combination.

Cone-beam computed tomography of the head in standing equids

BackgroundComputed tomography in standing horses has revolutionized diagnostic imaging. The O-arm®, a cone beam computed tomography (CBCT) scanner with a gantry opening of 96.5 cm is routinely used for image-guided spine and neurosurgery in humans. The aim of this study is to describe the set-up and first experiences using the O-arm® to achieve CBCT imaging of the head in standing horses.CT imaging of the predefined region of interest (ROI) was tested on 2 cadaveric heads, concentrating on centering issues within the gantry, as well as determining the number of scans needed per ROI. All horses presented with head-related diseases and subjected to a CBCT examination between February 2015 and November 2016 for CBCT were included. Per scan, a limited field of view, i.e. a cylindrical volume of 21 cm in diameter and 16 cm in height was acquired within 13 s. Depending on the dimensions of the ROI, the minimum number of scans could range from one to six, if the entire equine head is to be examined in an adult horse.ResultsSixty-eight horses were included, five of which had a follow-up CBCT exam, and two of which were presented twice for two different indications (75 clinical cases). A total number of 449 acquired three-dimensional (3D) scans were recorded for these 75 cases. Two-hundred and forty-two 3D scans (54%) were considered as diagnostic quality. The imaging procedure was generally well tolerated by the sedated, standing equid, and diagnostic studies were performed in 73 out of 75 cases (97.3%). Motion artefacts and inadequate centering of the ROI were the most common reasons for non-diagnostic quality images and repeat scans of the same ROI.ConclusionsCBCT is a valuable imaging modality for the equine head. Advantages of the O-arm® compared to a conventional multi-slice helical CT for imaging of the head in standing equids include the rapid image acquisition, the gantry’s mobility in all dimensions, and the free movability of the entire imaging unit. Disadvantages include the considerable sensitivity to motion artefact, increased scatter, low soft tissue contrast and the limited dimensions of the field of view.

Evaluation of the best single‑energy scanning in energy spectrum CT in lower extremity arteriography

The present study aimed to apply the best single-energy (SE) scanning in energy spectrum computed tomography (CT) to evaluate the usefulness of lower extremity arterial angiography imaging in patients with lower extremity arterial occlusive disease. A total of 64 patients diagnosed with lower extremity arterial occlusive disease were randomly selected and divided into either the experimental group (n=32) or the control group (n=32). The two treatment groups were scanned for lower extremity arteriography using the best SE scanning mode of energy spectrum CT Gemstone imaging (GSI) and mixed energy scanning mode of multi-slice helical CT (MSCT). The CT images, image noise, contrast-to-noise ratio (CNR) and quality scores of the images of lower extremity arteries between the two groups were compared. Image quality of the two experimental groups were independently evaluated by two imaging diagnostic physicians. The CT scores and CNR of the lower extremity arteries were significantly higher in the experimental group compared with the control group (P<0.01). No statistically significant differences in the background noise between the two groups were observed (P<0.05). The image quality scores of two groups, with the differences between the two diagnosticians, were found to be statistically significant (P<0.01). In the lower extremity arterial angiography, the image quality of the best SE in the CT GSI scanning mode was observed to be superior to that taken using MSCT mixed energy scanning mode.

P049] Moving forward to personalized pediatric dosimetry on computed tomography applications

Purpose Personalized dosimetry is of high interest in pediatric applications where exposure to ionizing radiation is widely debated. This study intends to create an organ dose database for pediatric reference individuals undergoing computed tomography (CT) examinations. The data will permit quick estimates of organ effective doses for patients of different age, gender, and examination procedure. Methods The GATE MC toolkit [1] was used for modeling a multislice helical CT system. The energy spectrum was calculated using Spektr software, and consequently imported in GATE as a gamma-particle point source with an almost continuous helical movement. To validate our results, simulations were performed with the standard CTDI head/body phantoms. A thin-walled ionization chamber was simulated according to the manufacturer specifications at 1 center, and 4 peripheral positions. Five pediatric computational models in the 5–15 y age-range [2] , [3] , were used to simulate realistic helical chest protocols and compare the variations on absorbed dose/organ. Results The CT scanner model was validated against experimental CTDI measurements with differences being lower than ∼18%. The simulated dose variations for the different pediatric phantoms are presented. Indicatively, normalized absorbed doses for selected organs inside the scan coverage varied between 25–35%, and 43–51% for 5 vs. 8, and 8 vs. 11 years-old girls respectively. Conclusions This is an ongoing study for the creation of a CT dosimetry pediatric database and for the quantification of the differences on the absorbed doses in tissue/organ level, using several models with variations in anatomical features. Every patient could be matched to the best anatomical model of this database (according to characteristics such as weight, height, age, gender) to provide more accurate and patient-specific organ doses.

VALUE OF MULTI-DETECTOR CT ANGIOGRAPHY IN CHRONIC ISCHEMIA OF LOWER LIMBS IN COMPARISON WITH THE DOPPLER ULTRASOUND

Background: Peripheral arterial disease (PAD) is one of the most common cardiovascular diseases in developed countries and is an emerging problem in developing countries. Duplex ultrasonography (DUS) has been used as the initial imaging modality in mild symptomatic PAD. Multi-slice helical CT angiography of arteries of the thigh represents a reliable means for the detection of relevant stenoses in patients with peripheral occlusive artery disease. Objective: To assess value of multi-detector computed tomography angiography (MDCTA) and to compare it with DUS to diagnose chronic ischemia of lower limbs. Methods: A prospective comparative study was conducted on 30 patients with chronic lower limbs ischemia of both limbs during the period from September 2015 to September 2016 at the Department of Diagnostic Radiology of Al-Imamein Al-Kadhimein Medical City, Baghdad, Iraq. DUS was done for all the patients and then MDCTA was done. Results: Thirty patients (20 males and 10 females) with a mean age of 57.1 ± 8.5 (range: 33 –80) years were included in this study. MDCTA detects 69 lesions (41 occluded segments and 28 stenotic segments) and DUS detects 58 lesions (35 occluded segments and 43 stenotic segments). In MDCTA, 8 patients (26.7%) had lesion in only one arterial segment, 13 patients (43.3%) had two segment lesions, 3 patients (10%) had three segment lesions, 4 patients (13.3%) with four lesions and only two patients (6.7%) had lesions in five arterial segments. Regarding the findings of the DUS one segment lesion was detected in 13 patients (43.3%), two segment lesions in 11 (36.7%), three segment lesions in 2 (6.7%), four segment lesions in 3 (10.0%) and only five segment lesions in only one patient (3.3). Furthermore, the measure of agreement between both MDCTA and DUS in the number of lesions detected revealed a good agreement between both tests, (Kappa = 0.81) with a percent agreement of (86.6%). Conclusion: Multi-detector CT angiography is a fast, accurate, safe and a minimally-invasive imaging modality which may be used in cases of PAD for diagnosis, grading and for preoperative assessment of lower limb arterial disease. Keywords: Multi-detector CT Angiography, chronic ischemia of lower limbs, doppler ultrasound Citation: Kadhim MA, Eisa YA, Mohammed SJ. Value of multi-detector CT angiography in chronic ischemia of lower limbs in comparison with the doppler ultrasound. Iraqi JMS. 2018; 16(2): 144-151. doi: 10.22578/IJMS.16.2.5

The sphenopalatine foramen in man: anatomical, radiological and endoscopic study.

Epistaxis is a frequent problem otorhinolaryngologists faces of in their practice. The variations of the sphenopalatine foramen (SPF) and consequ-ently the artery may be one of the major sources of such bleeding. The present work aimed to localise the site of SPF and also to illustrate its different shapes, number and any other variation. In the current study, 20 adult skulls of both sexes with total 40 half skulls were used in addition to 20 heads of adult living subjects of both sexes aged between 30 and 60 years examined with multislice helical com-puted tomography with 3-dimensional reconstruction of SPF. Then, examination of another ten dried skulls with endoscope was performed. The number of the SPF is varied being single in nearly 80% and multiple in 20% of examined cases. The shape of the foramen also is varied; regular in 67.5% and irregular in 32.5% of all cases. The site of the foramen on the lateral nasal wall is placed in the superior meatus in most of examined skulls (62.5%) while in the rest (37.5%) they are found in the superior meatus and extending to the middle one. There are variation of the number, shape and site of the SPF, and consequently of the branches of the sphenopalatine artery, and this may explain the surgical failure in management of severe epistaxis. The data obtained from the current work support the predication of more than one sphenopalatine ar-teries and gives ample knowledge on the endoscopic study of the lateral nasal wall and consequently the surgical treatment of severe epistaxis. (Folia Morphol 2018; 77, 2: 345-355).

Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

Improved linear interpolation algorithm for multi-slice helical CT

Improved linear interpolation algorithm for multi-slice helical CT

CT and MRI features of aggressive angiomyxoma

Objective To analyze the imaging features of aggressive angiomyxoma (AAM) on CT and MRI. Methods Seven patients with pathologically confirmed AAM had CT and/or MRI examination within 1 week prior to surgery. Six patients had multi-slice helical CT scanning while four of the six patients had multi-phase contrast enhancement. Five patients had MR scanning with contrast administration covering the chest, mid-abdomen or pelvis. The imaging and pathological findings were retrospectively reviewed. Results (1) CT presentations: pre-contrast CT images revealed isodensity (1 case), heterogeneous density (5 cases), cystic degeneration (2 cases) and mural nodule (2 cases). Contrast CT images showed homogeneous and gradual enhancement (1 case), heterogeneous and progressive enhancement (3 cases), whorl sign (3 cases) and opacification of small vessels (3 cases). (2) On MR images, five cases showed high or slightly high signal on T2WI; three cases presented with whorl sign; two cases had cystic degenerations. Iso-signal or low-signal was shown at T1WI in all five cases. DWI demonstrated high or mildly high signal in five cases. At contrast images, a whole-lesion homogeneous and gradual enhancement was present in one case. Four cases revealed progressive and expanding enhancement, where whorl sign and gradual enhancement were present in three cases. A progressive ascending pattern of time-signal curve was delineated in three cases. (3) Microscopically, the tumor comprises of poorly-defined satellite or spindle cells with sparse cytoplasm and varied sizes of vessels, which distribute among stroma with rich collagen fibre and myxoid. Those components were heterogeneous to congregate compact cell cluster. The stroma in four cases was abundant in collagen fibre that was aligned with myxoid stroma and tumor cell alternately. Conclusion AAM exhibits characteristic CT and MRI features. The imaging features correlated well with pathological findings. Key words: Myxoma; Tomography,X-ray computed; Magnetic resonance imaging; Pathology

Computer-assisted surgery planning in children with complex liver tumors identifies variability of the classical Couinaud classification

BackgroundIn complex malignant pediatric liver tumors there is an ongoing discussion regarding surgical strategy; for example, primary organ transplantation versus extended resection in hepatoblastoma involving 3 or 4 sectors of the liver. We evaluated the possible role of computer-assisted surgery planning in children with complex hepatic tumors. MethodsBetween May 2004 and March 2016, 24 Children with complex liver tumors underwent standard multislice helical CT scan or MRI scan at our institution. Imaging data were processed using the software assistant LiverAnalyzer (Fraunhofer Institute for Medical Image Computing MEVIS, Bremen, Germany). Results were provided as Portable Document Format (PDF) with embedded interactive 3-dimensional surface mesh models. ResultsMedian age of patients was 33months. Diagnoses were hepatoblastoma (n=14), sarcoma (n=3), benign parenchyma alteration (n=2), as well as hepatocellular carcinoma, rhabdoid tumor, focal nodular hyperplasia, hemangioendothelioma, or multiple hepatic metastases of a pancreas carcinoma (each n=1). Volumetry of liver segments identified remarkable variations and substantial aberrances from the Couinaud classification. Computer-assisted surgery planning was used to determine surgical strategies in 20/24 children; this was especially relevant in tumors affecting 3 or 4 liver sectors. Primary liver transplantation could be avoided in 12 of 14 hepaoblastoma patients who theoretically were candidates for this approach. ConclusionsComputer-assisted surgery planning substantially contributed to the decision for surgical strategies in children with complex hepatic tumors. This tool possibly allows determination of specific surgical procedures such as extended surgical resection instead of primary transplantation in certain conditions.

Estimating local noise power spectrum from a few FBP-reconstructed CT scans.

Traditional ways to estimate 2D CT noise power spectrum (NPS) involve an ensemble average of the power spectrums of many noisy scans. When only a few scans are available, regions of interest are often extracted from different locations to obtain sufficient samples to estimate the NPS. Using image samples from different locations ignores the nonstationarity of CT noise and thus cannot accurately characterize its local properties. The purpose of this work is to develop a method to estimate local NPS using only a few fan-beam CT scans. As a result of FBP reconstruction, the CT NPS has the same radial profile shape for all projection angles, with the magnitude varying with the noise level in the raw data measurement. This allows a 2D CT NPS to be factored into products of a 1D angular and a 1D radial function in polar coordinates. The polar separability of CT NPS greatly reduces the data requirement for estimating the NPS. The authors use this property and derive a radial NPS estimation method: in brief, the radial profile shape is estimated from a traditional NPS based on image samples extracted at multiple locations. The amplitudes are estimated by fitting the traditional local NPS to the estimated radial profile shape. The estimated radial profile shape and amplitudes are then combined to form a final estimate of the local NPS. We evaluate the accuracy of the radial NPS method and compared it to traditional NPS methods in terms of normalized mean squared error (NMSE) and signal detectability index. For both simulated and real CT data sets, the local NPS estimated with no more than six scans using the radial NPS method was very close to the reference NPS, according to the metrics of NMSE and detectability index. Even with only two scans, the radial NPS method was able to achieve a fairly good accuracy. Compared to those estimated using traditional NPS methods, the accuracy improvement was substantial when a few scans were available. The radial NPS method was shown to be accurate and efficient in estimating the local NPS of FBP-reconstructed 2D CT images. It presents strong advantages over traditional NPS methods when the number of scans is limited and can be extended to estimate the in-plane NPS of cone-beam CT and multislice helical CT scans.

Clinical imaging contrast agents - inception through lifecycle

Event Abstract Back to Event Clinical imaging contrast agents - inception through lifecycle Benjamin Yeh1 1 University of California, San Francisco, Radiology and Biomedical Imaging, United States Introduction The introduction of injectable contrast agents transformed medical imaging such that CT and MRI became critical first line tests for broad spectrums of clinical diagnosis and treatment monitoring. Importantly, it was the interplay between medical scanner breakthroughs and contrast agent availability that was central driving up the value of diagnostic imaging in the past half century. As medical imaging scanners improved, our understanding of how contrast agents can be tailored to optimally highlight disease became amongst the most critical topics of medical research. Discussion The usage of existing clinical contrast agents is now radically different than what was initially conceived when the agents were first introduced. For example, iodinated contrast agents were initially introduced for the sole purpose of highlighting the renal excretory system at plain film imaging. Since then, iodinated agents have taken on vastly increased roles for defining vasculature at minimally invasive angiographic studies and for defining global anatomy in CT scans. Further introduction of variant iodinated benzene rings with different physicochemical properties opened new imaging applications, such as cholangiographic and safer intravenous imaging. Similarly, the introduction of new imaging technology such as helical multislice CT and dual energy imaging dramatically changed the capabilities of the entire class of iodinated agents. Similar changes occurred with gadolinium-based MRI contrast material which quickly altered the landscape of MR imaging across all organ systems. However, as usage proliferated, so did the understanding of toxicities from contrast agents. Some toxicities, such as preventative measures for contrast-induced nephropathy and metformin-related lactic acidosis, became deeply ingrained in clinical practice even though the prevalence and severity of such entities were not well studied and subsequently were found to be far lower than initially thought. Conversely, toxicities of gadolinium chelates were exposed only after decades of use and resulted in near crisis as the magnitude of the contrast-related disease was studied. Conclusion: The understanding of the intimate connection between medical scanner capabilities and inevitable evolution and biomedical contrast material physicochemical properties is critical to consider for the development of any new contrast agent. Keywords: MRI, contrast agent, biomedical application Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Imaging with biomaterials Citation: Yeh B (2016). Clinical imaging contrast agents - inception through lifecycle. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02933 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Benjamin Yeh Google Benjamin Yeh Google Scholar Benjamin Yeh PubMed Benjamin Yeh Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

SU‐E‐I‐93: Improved Imaging Quality for Multislice Helical CT Via Sparsity Regularized Iterative Image Reconstruction Method Based On Tensor Framelet

Purpose:Inspired by compressive sensing, sparsity regularized iterative reconstruction method has been extensively studied. However, its utility pertinent to multislice helical 4D CT for radiotherapy with respect to imaging quality, dose, and time has not been thoroughly addressed. As the beginning of such an investigation, this work carries out the initial comparison of reconstructed imaging quality between sparsity regularized iterative method and analytic method through static phantom studies using a state‐of‐art 128‐channel multi‐slice Siemens helical CT scanner.Methods:In our iterative method, tensor framelet (TF) is chosen as the regularization method for its superior performance from total variation regularization in terms of reduced piecewise‐constant artifacts and improved imaging quality that has been demonstrated in our prior work. On the other hand, X‐ray transforms and its adjoints are computed on‐the‐fly through GPU implementation using our previous developed fast parallel algorithms with O(1) complexity per computing thread. For comparison, both FDK (approximate analytic method) and Katsevich algorithm (exact analytic method) are used for multislice helical CT image reconstruction.Results:The phantom experimental data with different imaging doses were acquired using a state‐of‐art 128‐channel multi‐slice Siemens helical CT scanner. The reconstructed image quality was compared between TF‐based iterative method, FDK and Katsevich algorithm with the quantitative analysis for characterizing signal‐to‐noise ratio, image contrast, and spatial resolution of high‐contrast and low‐contrast objects.Conclusion:The experimental results suggest that our tensor framelet regularized iterative reconstruction algorithm improves the helical CT imaging quality from FDK and Katsevich algorithm for static experimental phantom studies that have been performed.