Computed Tomography Contrast Research Articles

Radiation exposure of patients undergoing multiple-slice CT scans in Romania

Abstract Ionizing radiation is largely used in medicine due to its role in the diagnosis and treatment of patients. In the past 50 years computed tomography (CT) has become indispensable for medical practice because it offers sub-millimeter cross-sectional imaging of any region of the body. New CT scanners use thinner slices, providing more accurate results, but also an increased radiation exposure with possible long-term harmful effects for the patients. The parameter used as an indicator of radiation dose in CT is the dose-length product (DLP). The study included 4507 patients who were CT scanned using a 16, 32, 64 or 128-slice CT machine. DLP was measured for head, sinuses, thorax, abdomen, pelvis, abdomen+pelvis, and trunk scans - regions for which the health authorities have established national diagnostic reference levels (DRL - the expected radiation dose received by a patient in CT). One-way ANOVA was used to analyse data considering the use of contrast agents, the gender, age, and weight of patients. Average DLP values were higher (up to 80%) than national DRL for all regions in 64 and 128-slice scans. The highest DLP values were registered in contrast CT for all scanners (p < 0.01); the maximum average (a threefold increase compared to DRL) was measured in the 32-slice sinuses contrast CT. Average DLP correlated with patients’ gender and weight (p < 0.01), but the influence was lower compared to the use of contrast agents. In conclusion, CT scans acquired using thinner slices lead to more accurate results and high-quality images, but the study suggests an increased radiation exposure. CT has an uncontestable contribution to a precise and rapid diagnosis, but more attention must be given to the stochastic effects risks associated with the radiation dose received during a CT scan. Are all scans necessary? Do all patients really need to receive high doses? The role of the practitioner is decisive, and the justifiable process is “a must” in all radiodiagnosis practices. Key messages • CT doses must be kept “as low as reasonably achievable” while maintaining diagnostic image quality. • Justification, dose limitation, and optimisation are fundamental principles of radioprotection.

Combination of FDG PET/CT radiomics and clinical parameters for outcome prediction in patients with non-Hodgkin's lymphoma.

The purposes was to build model incorporating PET + computed tomography (CT) radiomics features from baseline PET/CT + clinical parameters to predict outcomes in patients with non-Hodgkin lymphomas. Cohort of 138 patients with complete clinical parameters and follow up times of 25.3 months recorded. Textural analysis of PET and manual correlating contouring in CT images analyzed using LIFE X software. Defined outcomes were overall survival (OS), disease free-survival, radiotherapy, and unfavorable response (defined as disease progression) assessed by end of therapy PET/CT or contrast CT. Univariable and multivariable analysis performed to assess association between PET, CT, and clinical. Male (P = 0.030), abnormal lymphocytes (P = 0.030), lower value of PET entropy (P = 0.030), higher value of SHAPE sphericity (P = 0.002) were significantly associated with worse OS. Advanced stage (III or IV, P = 0.013), abnormal lymphocytes (P = 0.032), higher value of CT gray-level run length matrix (GLRLM) LRLGE mean (P = 0.010), higher value of PET gray-level co-occurrence matrix energy angular second moment (P < 0.001), and neighborhood gray-level different matrix (NGLDM) busyness mean (P < 0.001) were significant predictors of shorter DFS. Abnormal lymphocyte (P = 0.033), lower value of CT NGLDM coarseness (P = 0.082), and higher value of PET GLRLM gray-level nonuniformity zone mean (P = 0.040) were significant predictors of unfavorable response to chemotherapy. Area under the curve for the three models (clinical alone, clinical + PET parameters, and clinical + PET + CT parameters) were 0.626, 0.716, and 0.759, respectively.

Novel intravascular tantalum oxide-based contrast agent achieves improved vascular contrast enhancement and conspicuity compared to Iopamidol in an animal multiphase CT protocol

BackgroundTo assess thoracic vascular computed tomography (CT) contrast enhancement of a novel intravenous tantalum oxide nanoparticle contrast agent (carboxybetaine zwitterionic tantalum oxide, TaCZ) compared to a conventional iodinated contrast agent (Iopamidol) in a rabbit multiphase protocol.MethodsFive rabbits were scanned inside a human-torso-sized encasement on a clinical CT system at various scan delays after intravenous injection of 540 mg element (Ta or I) per kg of bodyweight of TaCZ or Iopamidol. Net contrast enhancement of various arteries and veins, as well as image noise, were measured. Randomized scan series were reviewed by three independent readers on a clinical workstation and assessed for vascular conspicuity and image artifacts on 5-point Likert scales.ResultsOverall, net vascular contrast enhancement achieved with TaCZ was superior to Iopamidol (p ≤ 0.036 with the exception of the inferior vena cava at 6 s (p = 0.131). Vascular contrast enhancement achieved with TaCZ at delays of 6 s, 40 s, and 75 s was superior to optimum achieved Iopamidol contrast enhancement at 6 s (p ≤ 0.036. Vascular conspicuity was higher for TaCZ in 269 of 300 (89.7%) arterial and 269 of 300 (89.7%) venous vessel assessments, respectively (p ≤ 0.005), with substantial inter-reader reliability (κ = 0.61; p < 0.001) and strong positive monotonic correlation between conspicuity scores and contrast enhancement measurements (ρ = 0.828; p < 0.001).ConclusionTaCZ provides absolute and relative contrast advantages compared to Iopamidol for improved visualization of thoracic arteries and veins in a multiphase CT protocol.Relevance statementThe tantalum-oxide nanoparticle is an experimental intravenous CT contrast agent with superior cardiovascular and venous contrast capacity per injected elemental mass in an animal model, providing improved maximum contrast enhancement and prolonged contrast conspicuity. Further translational research on promising high-Z and nanoparticle contrast agents is warranted.Key PointsThere have been no major advancements in intravenous CT contrast agents over decades.Iodinated CT contrast agents require optimal timing for angiography and phlebography.Tantalum-oxide demonstrated increased CT attenuation per elemental mass compared to Iopamidol.Nanoparticle contrast agent design facilitates prolonged vascular conspicuity.Graphical

Implant dynamics, inner structure, and their impact on drug release of in situ forming implants uncovered through CT imaging

In situ forming implants (ISFIs) composed of biodegradable polymers and biocompatible solvents are generally designed for sustained drug release. In this study, a non-invasive computed tomography (CT) imaging approach is used to achieve real time imaging of ISFIs in vivo and in vitro using leuprolide acetate in situ forming implant as a model drug product. The process of implant formation, inner structure change and their impact on drug release were elucidated. Real-time drug distribution was unveiled by the CT contrast agent, iohexol, where it shows a core-shell structure of the deposition. The incorporation of leuprolide acetate (LA) led to a reduced extent of burst release, prolongated release profile, and extended implant size expansion. LA was found to interact with the solvent and slowed down the polymer phase inversion, thus significantly changed the drug distribution in the implant and reduced the drug release. The implant inner structure identified through SEM, implant size change, and polymer degradation along with the CT real time imaging all consistently support the implant formation differences and their implant on the drug release. Similar patterns of implant size expansion and iohexol distribution in the implants were observed both in vitro and in vivo for the implants with and without LA. The comprehensive understanding of the impact of implant formation on drug release through real time CT imaging facilitates the ISFI product development and evaluation.

Single-Atom Iridium Nanozyme-Based Persistent Luminescence Nanoparticles for Multimodal Imaging-Guided Combination Tumor Therapy.

Persistent luminescence nanoparticles (PLNPs) can achieve autofluorescence-free afterglow imaging, while near-infrared (NIR) emission realizes deep tissue imaging. Nanozymes integrate the merits of nanomaterials and enzyme-mimicking activities with simple preparation. Here PLNPs are prepared of Zn1.2Ga1.6Ge0.2O4:Cr0.0075 with NIR emission at 700 nm. The PLNPs are then incubated with IrCl3 solution, and the nanoparticles are collected and annealed at 750 °C to obtain iridium@PLNPs. Iridium is observed on the PLNPs at the atomic level as a single-atom nanozyme with peroxidase-like catalytic activity, photothermal conversion, and computed tomography (CT) contrast capability. After coating with exosome membrane (EM), the Ir@PLNPs@EM composite exhibits long-lasting NIR luminescence, peroxidase-like catalytic activity, photothermal conversion, and CT contrast capability, with the targeting capability and biocompatibility from EM. Thus, NIR afterglow/photothermal/CT trimodal imaging-guided photothermal-chemodynamic combination therapy is realized as validated with the in vitro and in vivo inhibition of tumor growth, while toxicity and side effects are avoided as drug-free treatment. This work offers a promising avenue for advanced single-atom nanozyme@PLNPs to promote the development of nanozymes and PLNPs for clinical applications.

Steroid-resistant immunoglobulin G4-related coronary arteritis: A case report

Abstract Background Immunoglobulin G4 (IgG4)-related diseases are systemic fibroinflammatory disease characterized by extensive infiltration of IgG4-positive plasma cells in the affected tissue(s), with high plasma levels of IgG4. However, coronary involvement is rare. Case Summary A 70-year-old man was diagnosed with IgG4-related coronary arteritis, pancreatitis, and cholangitis during full-body contrast computed tomography (CT) examination prior to surgery for an iliac artery aneurysm. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT showed increased uptake of 18F-FDG in the pancreas, extrahepatic bile ducts, and proximal right coronary artery (RCA). Despite the patient being asymptomatic, the RCA showed severe stenosis. The patient was administered a conservative treatment with prednisolone, 30 mg/day, gradually tapered to 5 mg/day, for 6 months. Two years later, contrast CT showed improvement of the pancreatic and bile duct lesions; however, the steroid therapy had not improved the coronary artery lesions, and gradual progression of the lesions was observed. Percutaneous coronary intervention was performed with a cutting balloon in the RCA, and good patency was maintained for 1 year after the procedure. Discussion Steroid therapy is the first-line treatment for IgG4-related diseases; however, there may be some refractory cases. The stenotic and aneurysmal type IgG4-related coronary arteritis are life-threatening; therefore, we performed revascularization using balloon angioplasty. Determining the optimal revascularization technique for drug-refractory cases requires further investigation.

Retroperitoneal lymphangioma in a tertiary care hospital of North India

Less than 200 cases of retroperitoneal lymphangiomas (RL), a rare type of benign cystic tumour of the lymphatic system that makes about 1% of all lymphangiomas, have been documented to date. Their rarity makes preoperative diagnosis challenging. 95% of lymphangiomas are found in the head, neck, and axilla where they are most frequently found. We are presenting a 30 years old woman, who presented to outpatient department (OPD) of general surgery with symptoms of recurrent left lumbar pain, radiating towards inguinal region for one month. The contrast computed tomography (CT) scan of abdomen and pelvis defined a large thin walled homogenous non enhancing hypodense cystic lesion in left side of abdomen in retroperitoneal location from left lobe of liver till pelvis on left side craniocaudally. The patient was planned for exploratory laparotomy. Midline laparotomy was performed. A cystic lymph-filled tumour was detected in the abdominal cavity adjacent to the bowel loops. Histologically the mass contained variable-sized cystic spaces lined by flattened endothelium consistent with lymphatic vessels, which on immunostaining were positive for CD31 and negative for Pan CK. The patient was discharged satisfactorily. In conclusion, retroperitoneal lymphangioma presents vaguely as abdominal pain or mass and grown to large sizes without causing any significant symptom. Tumour markers for the excised tissue are important for diagnosis. Laparotomy or laparoscopy are the two surgical excision methods used to treat retroperitoneal cystic lymphangioma and it responds well to excision.

Accuracy of convex probe EBUS-TBNA versus FDG-PET/CT imaging in diagnosis and mediastinal staging of lung cancer patients; an Egyptian Experience

BackgroundAppropriate staging of lung cancer is of paramount importance, as it customizes treatment and predicts prognosis. Both Fludeoxyglucose-18 (FDG) positron emission tomography (PET) combined with contrast computed tomography (CT) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are two widely used diagnostic modalities in the field of staging & diagnosis of lung malignancies, the former depends on image analysis while the later enables real-time sampling of lymph nodes under sonographic guidance.ObjectiveTo compare the diagnostic and staging accuracy of convex probe EBUS-TBNA versus FDG – PET/CT as two modalities in diagnosis & mediastinal staging of lung cancer patients.MethodsThis prospective, observational (daignostic accuracy) research was performed on 40 cases with lung malignancies. All cases were examined via FDG-PET/CT followed by convex probe EBUS-TBNA for diagnosis & staging of concurrent mediastinal lymphadenopathy (MLN).ResultsThe diagnostic yield of EBUS-TBNA reached 92.5% (37/40) compared to 70% (28/40) for FDG-PET/CT. There was poor agreement between EBUS-TBNA & FDG-PET/CT regarding (MLN) staging (k = 0.043), in 16/40 patients (40%), EBUS MLN staging matched that of FDG-PET/CT, while in 24/40(60%) there were discrepancies between the two diagnostic modalities; 18/40(45%) were up-staged after EBUS while 6/40(15%) were down staged after EBUS. In addition, EBUS-TBNA confirmed occult mediastinal nodal involvement in 9/10 FDG-PET/CT negative scans (N0). The overall diagnostic accuracy of EBUS-TBNA was significantly greater than FDG-PET/CT in staging of lung cancer (97.37% & 70% respectively, p < 0.001).ConclusionEBUS-TBNA is a minimally invasive procedure that we currently recommend as a first choice for MLN staging.Trial registrationClinicalTrials.gov, NCT06479798. Registered 26 June 2024—Retrospectively registered, https://clinicaltrials.gov/study/NCT06479798.

Computed Tomographic Findings of Liver Cirrhosis in Dogs: Comparison between Compensated and Decompensated Cirrhosis.

This study aimed to describe computed tomography (CT) characteristics of histologically confirmed cirrhosis and to compare these CT characteristics between compensated and decompensated cirrhosis. Sixteen dogs who underwent contrast CT and histopathological examinations were included; eleven dogs were assigned to the compensated group, and five dogs were assigned to the decompensated group. Irregular hepatic contours with a diffuse nodular distribution and hepatic lymph node enlargement are common concomitant features of cirrhotic livers on CT images. The enhancement patterns of the regenerative nodules and hepatic parenchyma were not significantly different from each other. Hypoattenuating areas with delayed contrast enhancement indicating fibrotic tissue were confirmed in 56.3% of cases. Hypoattenuating wedge-shaped area or nodule with minor or no contrast enhancement (histopathologically confirmed as focal necrosis) were confirmed in 37.5% of cases. Among CT variables, only normalized liver volume and portal vein-to-aorta ratio were significantly lower (p = 0.038 and 0.003, respectively) in the decompensated group. In conclusion, this study presented the CT features of cirrhosis and identified CT features that can discriminate between compensated and decompensated cirrhosis. Specifically, lower normalized liver volume and the portal vein-to-aorta ratio might be useful indicators for the progression of cirrhosis to the decompensated phase.

Radiography students' knowledge, attitude and practice relating to infection prevention and control in the use of contrast media injectors in computed tomography.

Radiography students complete professional placements in various clinical settings and must adhere to distinct infection prevention and control (IPC) protocols. The aim of this study was to explore radiography students' training, knowledge, attitudes, and practice (KAP) relating to IPC in the use of contrast media injectors in computed tomography (CT). An online survey study was undertaken with radiography students enrolled at two Australian universities. Survey questions related to contrast media training and KAP regarding IPC in CT. Data was summarised using descriptive statistics, with comparisons between experience in public and private practice. One free-text response question focused on non-adherence to IPC best practice, analysed using content analysis. In total, 40 students completed the survey (9% response rate). Reports of IPC and contrast media equipment training was high, with disposition for further training. Regarding IPC knowledge, 65% of students responded correctly to all 'knowledge' items (individual scores range: 60-100%). Low consensus was observed regarding whether gloves replace the need for hand hygiene and if CT contrast tubing poses risk to healthcare workers (85% each). Mean scores ranged from 41% to 100% regarding identification of sterile syringe and tubing components. Responses to the open-ended question were categorised into four themes: 'High non-adherence risk working conditions', 'attitudes and practice', 'knowledge', and 'prioritise good IPC practice'. Radiography students demonstrate varied comprehension of IPC regarding contrast media equipment, and results suggest need for collaborative efforts between academic institutions and clinical training sites to integrate IPC protocols into curricula and on-site training.

Enzyme-like nanoparticle-engineered mesenchymal stem cell secreting HGF promotes visualized therapy for idiopathic pulmonary fibrosis in vivo.

Stem cell therapy is being explored as a potential treatment for idiopathic pulmonary fibrosis (IPF), but its effectiveness is hindered by factors like reactive oxygen species (ROS) and inflammation in fibrotic lungs. Moreover, the distribution, migration, and survival of transplanted stem cells are still unclear, impeding the clinical advancement of stem cell therapy. To tackle these challenges, we fabricate AuPtCoPS trimetallic-based nanocarriers (TBNCs), with enzyme-like activity and plasmid loading capabilities, aiming to efficiently eradicate ROS, facilitate delivery of therapeutic genes, and ultimately improve the therapeutic efficacy. TBNCs also function as a computed tomography contrast agent for tracking mesenchymal stem cells (MSCs) during therapy. Accordingly, we enhanced the antioxidant stress and anti-inflammatory capabilities of engineered MSCs and successfully visualized their biological behavior in IPF mice in vivo. Overall, this study provides an efficient and forward-looking treatment approach for IPF and establishes a framework for a stem cell-based therapeutic system aimed at addressing lung disease.

Computed Tomography Imaging Guided Microenvironment-Responsive Ir@WO3-x Dual-Catalytic Nanoreactor for Selective Radiosensitization.

Radiotherapy (RT) is often administered, either alone or in combination with other therapies, for most malignancies. However, the degree of tumor oxygenation, damage to adjacent healthy tissues, and inaccurate guidance remain issues that result in discontinuation or failure of RT. Here, a multifunctional therapeutic platform based on Ir@WO3-x is developed which simultaneously addresses these critical issues above for precision radiosensitization. Ir@WO3-x nanoreactors exhibit strong absorption of X-ray, acting as radiosensitizers. Moreover, ultrasmall Ir enzyme-mimic nanocrystals (NCs) are decorated onto the surface of the nanoreactor, where NCs have catalyst-like activity and are sensitive to H2O2 in the tumor microenvironment (TME) under near infrared-II (NIR-II) light stimulation. They efficiently catalyze the conversion of H2O2 to O2, thereby ameliorating hypoxia, inhibiting the expression of HIF-1α, and enhancing RT-induced DNA damage in cancerous tissue, further improving the efficiency of RT. Additionally, in response to high H2O2 levels in TME, the Ir@WO3-x nanoreactor also exerts peroxidase-like activity, boosting exogenous ROS, which increases oxidative damage and enhances ROS-dependent death signaling. Furthermore, Ir@WO3-x can serve as a high-quality computed tomography contrast agent due to its high X-ray attenuation coefficient and generation of pronounced tumor-tissue contrast. This report highlights the potential of advanced health materials to enhance precision therapeutic modalities.

Clinical Audit in the Elderly by Assessing Hydration and Renal Functions Before and After Contrast CT Scans at District Headquarters Hospital, Dera Ismail Khan, Pakistan.

Introduction Contrast-induced nephropathy (CIN) is a serious risk involved in computed tomography (CT) scans, particularly for older people. The main idea of this clinical audit was to assess current practices regarding renal function tests (RFTs) and hydration status before and after contrast CT scans in older patients at District Headquarters Hospital (DHQ), Dera Ismail Khan, Pakistan, and to implement recommendations for improvement. CIN is a form of acute kidney injury that occurs after the administration of contrast dye used in imaging procedures and is characterized by a sudden deterioration in renal functions. Methods This clinical audit checked adherence to renal protection protocols in elderly patients undergoing contrast CT scans. Conducted over three cycles from July 5 to August 15, 2022, this clinical audit included 30 patients aged 75 and above. Each cycle had 10patients, divided equally between males and females, and further categorized into age groups of 75-85 years and 86-95 years. Data collection involved reviewing patient files, medication charts, and CT scan reports. Compliance with RFT documentation and hydration before and after the CT scan was assessed against the standards set by Basildon and Thurrock University Hospitals NHS Foundation Trust. Data were analyzed using Microsoft Excel 2023 (Microsoft® Corp., Redmond, WA), and graphs were created using Microsoft Word 2023 (Microsoft® Corp., Redmond, WA). Results The mean age ± standard deviation (SD) for males was 81.8 ± 5.01 in the first cycle, 83.4 ± 6.46 in the second cycle, and 82.4 ± 4.72 in the third cycle. For females, the mean age ± SD was 83.2 ± 5.80 in the first cycle, 85.2 ± 6.41 in the second cycle, and 83.0 ± 6.12 in the third cycle. The first audit cycle revealed that, while all patients (100%) had their RFTs documented before the CT scan, only 20% were adequately hydrated pre-scan, and none (0%) had RFTs performed post scan. Post-scan hydration was also low at 20%. These findings highlighted gaps in adherence to renal protection protocols. The second cycle showed improvements, with pre-scan hydration adherence increasing to 80%, post-scan RFTs to 60%, and post-scan hydration to 70%. By the third cycle, full compliance (100%) was achieved across all standards, including pre- and post-scan renal functions test and hydration. Conclusion The clinical audit at District Headquarters Hospital, Dera Ismail Khan, addressed gaps in renal protection protocols for elderly patients undergoing contrast CT scans. The audit improved adherence over three cycles through targeted interventions, including staff training, implementation of checklists, patient education, modifying the reporting format, and providing instructions in the local language. It also highlighted the importance of continuous education and regular monitoring. The clinical audit would be expanded to another hospital within the medical teaching institute, Dera Ismail Khan. This measure will maintain and enhance patient care, prevent CIN, and improve the renal health of elderly patients.

Charged Gold Nanoparticles for Target Identification-Alignment and Automatic Segmentation of CT Image-Guided Adaptive Radiotherapy in Small Hepatocellular Carcinoma.

Because of the challenges posed by anatomical uncertainties and the low resolution of plain computed tomography (CT) scans, implementing adaptive radiotherapy (ART) for small hepatocellular carcinoma (sHCC) using artificial intelligence (AI) faces obstacles in tumor identification-alignment and automatic segmentation. The current study aims to improve sHCC imaging for ART using a gold nanoparticle (Au NP)-based CT contrast agent to enhance AI-driven automated image processing. The synthesized charged Au NPs demonstrated notable in vitro aggregation, low cytotoxicity, and minimal organ toxicity. Over time, an in situ sHCC mouse model was established for in vivo CT imaging at multiple time points. The enhanced CT images processed using 3D U-Net and 3D Trans U-Net AI models demonstrated high geometric and dosimetric accuracy. Therefore, charged Au NPs enable accurate and automatic sHCC segmentation in CT images using classical AI models, potentially addressing the technical challenges related to tumor identification, alignment, and automatic segmentation in CT-guided online ART.

Comparison between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes using computed tomography

BACKGROUND Solid pseudopapillary neoplasms of the pancreas (SPN) share similar imaging findings with pancreatic ductal adenocarcinoma with cystic changes (PDAC with cystic changes), which may result in unnecessary surgery. AIM To investigate the value of computed tomography (CT) in differentiation of SPN from PDAC with cystic changes. METHODS This study retrospectively analyzed the clinical and imaging findings of 32 patients diagnosed with SPN and 14 patients diagnosed with PDAC exhibiting cystic changes, confirmed through pathological diagnosis. Quantitative and qualitative analysis was performed, including assessment of age, sex, tumor size, shape, margin, density, enhancement pattern, CT values of tumors, CT contrast enhancement ratios, “floating cloud sign,” calcification, main pancreatic duct dilatation, pancreatic atrophy, and peripancreatic invasion or distal metastasis. Multivariate logistic regression analysis was used to identify relevant features to differentiate between SPN and PDAC with cystic changes, and receiver operating characteristic curves were obtained to evaluate the diagnostic performance of each variable and their combination. RESULTS When compared to PDAC with cystic changes, SPN had a lower age (32 years vs 64 years, P &lt; 0.05) and a slightly larger size (5.41 cm vs 3.90 cm, P &lt; 0.05). SPN had a higher frequency of “floating cloud sign” and peripancreatic invasion or distal metastasis than PDAC with cystic changes (both P &lt; 0.05). No significant difference was found with respect to sex, tumor location, shape, margin, density, main pancreatic duct dilatation, calcification, pancreatic atrophy, enhancement pattern, CT values of tumors, or CT contrast enhancement ratios between the two groups (all P &gt; 0.05). The area under the receiver operating characteristic curve of the combination was 0.833 (95% confidence interval: 0.708-0.957) with 78.6% sensitivity, 81.3% specificity, and 80.4% accuracy in differentiation of SPN from PDAC with cystic changes. CONCLUSION A larger tumor size, “floating cloud sign,” and peripancreatic invasion or distal metastasis are useful CT imaging features that are more common in SPN and may help discriminate SPN from PDAC with cystic changes.

Role of Multidetector Computed Tomography with Contrast in Evaluation of Congenital Lung Malformations in Pediatric Age Group at a Tertiary Care Hospital: An Observational Study

Background: Computed tomography (CT) has a larger role in the noninvasive examination of congenital lung abnormalities, thanks to the introduction of multidetector CT (MDCT). If a surgical lesion is suspected, it is often necessary to use cross-sectional imaging, such as CT, for diagnosis confirmation, further lesion definition, and preoperative evaluation. Aims and Objectives: The aim of this study was to enhance comprehension of the occurrence and varieties of congenital lung abnormalities in children, as well as to assess and compare the diagnostic precision of MDCT with that of surgical intervention. Methodology: MDCT with contrast CT was performed in children with respiratory complaints and prenatal history of suspicion in targeted imaging for fetal anomalies (TIFFA) or congenital lung malformations (CLMs) using TOSHIBA 8 slice CT; the study population consisted of 40 pediatric patients with a history of chest anomalies during pregnancy in TIFFA or children with abnormal chest X-ray suspicion of lung anomalies for 18 months. Results: In a study of 40 pediatric patients who underwent MDCT with contrast to evaluate CLMs, 6 were excluded from further evaluation with contrast due to the absence of pulmonary anomalies on plain CT, leaving a possible diagnosis of s CLM in the remaining 34 cases. Of these, cystic pulmonary airway malformations (CPAM) (41.1%) were the most common, followed by congenital lobar emphysema (17.6%), bronchogenic cyst (14.7%), lung agenesis (11.6%), and phylogenetic lung. Conclusion: To notice the characteristics and related anomalies of CLMs and aid in the presurgical evaluation of CLMs, the study concludes that MDCT with contrast is the imaging of choice.

A detailed look in radioanatomical aspects of ligamentum arteriosum calcification in pediatric population

After birth, ductus arteriosus forms ligamentum arteriosum and sometimes can be calcified. Ligamentum arteriosum calcification can be seen as subtle-punctate or coarse-linear between pulmonary artery and the aorta in the non-contrast computed tomography (CT) images, and between the pulmonary conus and the aortic knob in the chest radiography. In this study, we aim to estimate the prevalence of ligamentum arteriosum calcification on non-contrast CT and chest radiography in a pediatric population. Patients aged 0-18 years, who underwent non- contrast CT and chest radiography at Department of Radiology between March 1, 2020 and October 31, 2021 were evaluated retrospectively. It was examined whether there was ligamentum arteriosum calcification in non-contrast CT and chest radiography. If there is calcification, it was recommended as subtle-punctate or coarse-linear, and information was documented by grouping the patients’ age. If ligamentum arteriosum calcification was present, it was divided morphologically into two groups (subtle-punctate and coarse-linear) and classified according to the age groups. The research population consisted of 1003 patients. Non-contrast CT revealed calcification in 25.5% of patients (n=256). 11.3% of patients had subtle-punctate calcification, and 14.3% had coarse-linear calcification. Radiography had a 1.7% (n:17) detection rate for calcification. Ligamentum arteriosum calcification is a common finding in all age groups in the pediatric population. When reporting pediatric CT studies, radiologists should be able to distinguish ligamentum arteriosum calcification from other pathological and anatomical conditions and accept it as a normal finding in order to avoid unnecessary further investigations.

Ileosigmoid knotting: A rare cause of acute intestinal obstruction and peritonitis

Introduction: Ileosigmoid knotting (ISK) is one of the rarer causes of bowel obstruction compared to others. This is also called compound volvulus or double loop obstruction. The presentation symptoms are similar to those of other large bowel or distal intestinal obstructions. But the pathogeny’s or disease’s progression is rapid. So the patient develops ischemia or strangulation of the involved segment of the bowel earlier than the sigmoid or ceal volvulus. One of the challenges of the disease is that, especially in low-income countries like ours, there is no access to contrast computed tomography (CT), which is more sensitive diagnostic imaging. Case Report: A 58-year-old male patient presented to our hospital with abdominal pain for two days. He was referred from the primary hospital. The pain was initially central and later diffused to other parts of the abdomen. Associated with this, he was vomiting of ingested matter for more than two episodes. On physical examinations, he was in acute pain, and his vital signs showed a pulse rate of tachycardia at 127 BPM. On abdominal examination, he had distention and diffused tenderness with gardening. So we diagnosed him with peritonitis secondary to gangrenous sigmoid volvulus obstruction (SVO). So I chose the imaging that is available in our hospital, a plain abdominal X-ray. So the patient was resuscitated with normal saline, an antibiotic was initiated, and he was taken to the operation after giving consent. The ilium and sigmoid colon were gangrened and en bloc resection was done, and the jejunum and remaining 7 cm of ilium from the ileocecal valve were anastomosed. The patient was taken to or for a relook, and the anastomosis was disrupted, then refreshed, and both the proximal and distal segments were taken out as stomas. The output was significant and later developed a controlled entrocutaneous fistula, which was closed after three weeks. Conclusion: The prognosis is poor for ISK compared to other common types of volvulus and worse prognosis challenging management in conditions with both active and passive bowel ischemia which happened to our patients. Diagnosis is also challenging before the surgery. The abdominal X-ray and ultrasound are available and commonly the surgeon commonly will not send for this unless the patient is stable. Blind rectal tube deflation the common intervention in our setup with no access for sigmoidoscopy is not indicated for this non-surgical initial management rather with a highly suspicious diagnosis early resuscitation with early surgical treatment.

Computed tomography technologies to measure key structural features of polymeric biomedical implants from bench to bedside.

Implanted polymeric devices, designed to encourage tissue regeneration, require porosity. However, characterizing porosity, which affects many functional device properties, is non-trivial. Computed tomography (CT) is a quick, versatile, and non-destructive way to gain 3D structural information, yet various CT technologies, such as benchtop, preclinical and clinical systems, all have different capabilities. As system capabilities determine the structural information that can be obtained, seamless monitoring of key device features through all stages of clinical translation must be engineered intentionally. Therefore, in this study we tested feasibility of obtaining structural information in pre-clinical systems and high-resolution micro-CT (μCT) under physiological conditions. To overcome the low CT contrast of polymers in hydrated environments, radiopaque nanoparticle contrast agent was incorporated into porous devices. The size of resolved features in porous structures is highly dependent on the resolution (voxel size) of the scan. As the voxel size of the CT scan increased (lower resolution) from 5 to 50 μm, the measured pore size was overestimated, and percentage porosity was underestimated by nearly 50%. With the homogeneous introduction of nanoparticles, changes to device structure could be quantified in the hydrated state, including at high-resolution. Biopolymers had significant structural changes post-hydration, including a mean increase of 130% in pore wall thickness that could potentially impact biological response. By incorporating imaging capabilities into polymeric devices, CT can be a facile way to monitor devices from initial design stages through to clinical translation.

Pixel-by-pixel correction of beam hardening artifacts by bowtie filter in fan-beam CT

Objective. Beam hardening (BH) artifacts in computed tomography (CT) images originate from the polychromatic nature of x-ray photons. In a CT system with a bowtie filter, residual BH artifacts remain when polynomial fits are used. These artifacts lead to worse visuals, reduced contrast, and inaccurate CT numbers. This work proposes a pixel-by-pixel correction (PPC) method to reduce the residual BH artifacts caused by a bowtie filter. Approach. The energy spectrum for each pixel at the detector after the photons pass through the bowtie filter was calculated. Then, the spectrum was filtered through a series of water slabs with different thicknesses. The polychromatic projection corresponding to the thickness of the water slab for each detector pixel could be obtained. Next, we carried out a water slab experiment with a mono energy E = 69 keV to get the monochromatic projection. The polychromatic and monochromatic projections were then fitted with a 2nd-order polynomial. The proposed method was evaluated on digital phantoms in a virtual CT system and phantoms in a real CT machine. Main results. In the case of a virtual CT system, the standard deviation of the line profile was reduced by 23.8%, 37.3%, and 14.3%, respectively, in the water phantom with different shapes. The difference of the linear attenuation coefficients (LAC) in the central and peripheral areas of an image was reduced from 0.010 to 0.003 cm−1 and 0.007 cm−1 to 0 in the biological tissue phantom and human phantom, respectively. The method was also validated using CT projection data obtained from Activion16 (Canon Medical Systems, Japan). The difference in the LAC in the central and peripheral areas can be reduced by a factor of two. Significance. The proposed PPC method can successfully remove the cupping artifacts in both virtual and authentic CT images. The scanned object’s shapes and materials do not affect the technique.