Multidetector Computed Tomography Scans Research Articles

Prevalence of lung atelectasis in sedated dogs examined with computed tomography

BackgroundComputed tomography (CT) scanning of the lung is known to be a valuable tool when investigating lung pathology of the dog. During CT-scan the dog needs to be immobilized and general anesthesia has historically been considered as gold standard although being a more expensive and time-consuming alternative to sedation. Today, modern high speed multidetector CT-scanners offer new possibilities for sedation as an alternative. Both anesthesia and sedation can cause lung atelectasis, and this can be problematic when reading the CT-images since it potentially can masque or mimic lung pathology leading to misdiagnosis. The objective of this prospective analytic study was to investigate the prevalence of lung atelectasis and changes in lung attenuation over time in dogs that receive intravenous sedation and positioned in sternal recumbency.Results20 dogs without known lung pathology underwent three consecutive CT-scans of the lung; the first scan was initiated as soon as the dog was sufficiently sedated, the second scan approximately 5 min after the first one and the last scan after the dog’s orthopaedic scan was completed. The dogs received intravenous sedation in a combination of dexmedetomidine and butorphanol and were kept positioned in a strict sternal recumbency during sedation and exam. Each lung lobe was individually examined in an axial plane and measurements of dorsal, ventral, and mean lung attenuation were made. Atelectasis or areas with poorly aerated lung tissue were not detected as all parts of the lobes were normally aerated at all three scans. A statistically significant increase in lung attenuation between the first and the second scan (P = 0.03) and between the first and the third scan (P = 0.0004) was seen in the ventral part of the lobes.ConclusionsThis study indicates that CT-examination of the lungs can be performed on sedated dogs that are kept in a sternal recumbency without development of atelectasis. It also suggests that there is an early correlation between time and increase in lung attenuation.

3D render volume CT reconstruction of the bones and arteries of the hind digit of the dromedary camel (Camelus dromedarius)

BackgroundThe 3D computed tomography produces detailed images of the digit bones in addition to the angiograph render volume 3D of the CT shows the relation between the arteries, bones, and tissues of the digit. Therefore, the present study used those imaging techniques to provide a complete description of the digit bones and arteries’ origin, distribution, and course and their relations with surrounding structures in the Dromedary Camel. Which would serve as a guide for surgeons and students in distinguishing normal digit structures. The study used eight hind limbs of four adult camels of both sexes (two males and two females), aged 9–15 years (Mean ± SD, 11.80 ± 2.59 years). The samples were injected with latex with lead oxide were undergone 3D render volume CT (128-slice multi-detector CT scanning protocol) and angiography x-rays.ResultsThe blood vessels and correlated structures such as bones, tendons, and ligaments were examined using 3D CT in all directions, which was easier to view than angiography and dissected specimens. The arterial supply to the camel’s hind foot was the A. digitalis plantaris communis III. The angiography render volume 3D of CT explained the blood supply of the bones and joints of digital regions and showed a good visualization of the many digit arteries. The metatarsals, the phalanges, and the sesamoid bones were visualized. A. plantaris medialis superficialis, A. digitalis plantaris communis III, A. digitalis plantaris communis II and IV, A. interdigitalis, rami articularis medialis and lateralis to the fetlock joint, ramus medialis and ramus lateralis of the A. digitalis plantaris communis III, A. digitalis plantaris propriae III et IV abaxialis, A. digitalis plantaris propriae III et IV axialis, Ramus phalangis axialis and abaxialis of the first phalanx, Ramus phalangis axialis and abaxialis of the second and third phalanges, and A. metatarsae plantaris III were visualized. The study discovered new blood vessel sources in dromedary camels, such as the ramus articularis to the fetlock and the ramus plantaris phalangis abaxialis proximalis and distalis of the first phalanx.ConclusionsThe digital circulation angiography investigates the circulatory pattern of the camel hind digit, which can assist clinicians in diagnosing digit region affections. 3D CT explained improved visualization of bones and arteries, including many small branches in relation to surrounding structures, in some views better than others.

Morphometric Evaluation of the Lacrimal Sac Fossa in Anatolian Population Using Multidetector Computed Tomography

Background: To investigate the morphometric characteristics of the lacrimal sac fossa in Anatolian population using multidetector computed tomography (MDCT) images in surgical aspect.Materials and Methods: A total of 77 cranial MDCT scans were evaluated. The dimensions of the maxillary and the lacrimal bones forming the lacrimal sac fossa were measured in 3 axial planes (up-per, middle, and lower planes).Results: The mean maximum thickness of the maxillary bone at the upper, middle and lower planes were: 3.58 mm, 4.27 mm, and 5.81 mm; the mean midpoint thickness at each plane were: 2.76 mm, 2.51 mm, and 1.48 mm; the mean lacrimal bone thickness at each plane were: 0.72 mm, 0.65 mm, and 0.66 mm; the mean distance between anterior and posterior lacrimal crests at each plane were: 5.96 mm, 8.1 mm, and 4.63 mm; the mean angle between the lacrimal bone and the sagittal plane in males and females at the middle plane were: 132.73° and 131.46°; the mean length of the lacrimal sac fossa in males and females were: 15.82 mm and 14.02 mm.Conclusions: In Anatolian population, bone thicknesses of the lacrimal sac fossa were higher in ma-les, while the angle between the lacrimal bone and the sagittal plane was higher in females. This study indicated that osteotomies, which are the main target of dacryocystorhinostomy (DCR) inter-ventions, can be easily performed in the Anatolian population.

A novel dual-energy cone beam computed tomography device for assessment of jaw bone density

<h3>Objective</h3> To evaluate a novel dual-energy cone beam computed tomography (DE-CBCT) device for jaw bone density assessment. <h3>Study Design</h3> An ongoing clinical trial has enrolled 19 subjects with a target enrollment of 24 subjects. All subjects were 21 years and older and required a maxillofacial CT scan for standard-of-care diagnosis. Each subject received 2 examinations: one with a 64-slice multi-detector CT (MDCT) scanner and the second with the experimental DE-CBCT device (RCT720, Ray Co. Seoul, Korea). Asynchronous scanning of a custom hydroxyapatite phantom (concentrations of 0.8, 1.0 and 1.2 g/cc) provided calibration for bone density measurement. DICOM data from both CT examinations were imported into a custom version of OnDemand software<i>.</i> Calibration curves were generated from the MDCT and DE-CBCT scans of the hydroxyapatite phantoms. The MDCT and DE-CBCT scans of study subjects were superimposed and custom tools allowed calculation of bone density within a specified region of interest (ROI). Concordance between the MDCT- and DE-CBCT-derived bone densities was examined. <h3>Results</h3> In our preliminary assessments of data from current subjects, the mean calculated bone density in all the ROIs measured was 0.51 ± 0.27 g/cc for MDCT imaging and 0.50 ± 0.32 for DE-CBCT imaging. The range of the calculated bone densities was 0.06 to 1.1 g/cc for MDCT and 0.04 to 1.3 g/cc for DE-CBCT. Overall, there was strong correlation between bone densities calculated from MDCT scans with those calculated from DE-CBCT scans (r = 0.96, p <0.0001). Bland-Altman analysis identified a bias of 0.01 ± 0.1, and 95% limits of agreement range was -0.19 to 0.21. <h3>Conclusion</h3> The RCT720, a newly-developed DE-CBCT device, produced measurement of bone density equivalent to MDCT and overcomes the inaccuracies of bone density assessment using conventional CBCT scans. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel

Heart Rate-Dependent Degree of Motion Artifacts in Coronary CT Angiography Acquired by a Novel Purpose-Built Cardiac CT Scanner.

Although reaching target heart rate (HR) before coronary CT angiography (CCTA) is still of importance, adequate HR control remains a challenge for many patients. Purpose-built cardiac scanners may provide optimal image quality at higher HRs by further improving temporal resolution. We aimed to compare the amount of motion artifacts on CCTA acquired using a dedicated cardiac CT (DCCT) compared to a conventional multidetector CT (MDCT) scanner. We compared 80 DCCT images to 80 MDCT scans matched by sex, age, HR, and coronary dominance. Image quality was graded on a per-patient, per-vessel and per-segment basis. Motion artifacts were assessed using Likert scores (1: non-diagnostic, 2: severe artifacts, 3: mild artifacts, 4: no artifacts). Patients were stratified into four groups according to HR (<60/min, 60–65/min, 66–70/min and >70/min). Overall, 2328 coronary segments were evaluated. DCCT demonstrated superior overall image quality compared to MDCT (3.7 ± 0.4 vs. 3.3 ± 0.7, p < 0.001). DCCT images yielded higher Likert scores in all HR ranges, which was statistically significant in the 60–65/min, 66–70/min and >70/min ranges (3.9 ± 0.2 vs. 3.7 ± 0.2, p = 0.008; 3.5 ± 0.5 vs. 3.1 ± 0.6, p = 0.048 and 3.5 ± 0.4 vs. 2.7 ± 0.7, p < 0.001, respectively). Using a dedicated cardiac scanner results in fewer motion artifacts, which may allow optimal image quality even in cases of high HRs.

THE COMPARATIVE STUDY OF USG AND MDCT IN THE EVALUATION OF PELVIC MASSES IN FEMALES

Introduction: Pelvic masses in females of all ages are a routine gynaecological issue for which healthcare is sought, and in a populous country like India, these masses form a significant part of the disease burden. The evaluation of the female pelvis is a radiological necessity and a challenge. The foremost aim for any imaging modality in this scenario is to rule out malignancy in the mass, and further to characterise and define the mass so as to guide appropriate management of the patient. Of the wide range of imaging modalities available, ultrasonography and computed tomography are commonly available and extensively used for the evaluation of the varied female pelvic masses. We studied the ultrasonography and multi detector computed tomography findings and their usefulness in the diagnosis and characterization of various pelvic masses in females. Methodology: It was a prospective observational study, ranging over the duration of one and a half years,of 100 female patients fulfilling inclusion criteria, who underwent ultrasonography and multidetector computed tomography scanning in the Department of Radiodiagnosis at RNT medical college, Udaipur. Pelvic masses were evaluated for origin, size, margins, composition, vascularity, ascites, lymphadenopathy and other features to characterise as benign or malignant. Final diagnosis was by histopathological correlation. Results: The most common age group belonged to 35-45 years group (22%) followed by 55-65 years group (21%). Mean age for benign masses was 35.84 years and for malignant masses was 51.64 years. Ovarian origin was the commonest followed by uterine origin. Features like solid areas, ill-defined margins, lymphadenopathy and ascites favoured malignancy. Most common pathologies were adenocarcinoma ovary, carcinoma cervix, benign ovarian cysts and uterine fibroids. Conclusion: Ultrasonography is often the first imaging study performed in patients with symptoms related to the pelvis. Results indicated higher diagnostic capability of CT as a problem-solving tool. Overall diagnostic accuracy of CT was higher than USG in characterising both benign and malignant pelvic masses.

Patient-Specific Finite Element Modeling of the Whole Lumbar Spine Using Clinical Routine Multi-Detector Computed Tomography (MDCT) Data-A Pilot Study.

(1) Background: To study the feasibility of developing finite element (FE) models of the whole lumbar spine using clinical routine multi-detector computed tomography (MDCT) scans to predict failure load (FL) and range of motion (ROM) parameters. (2) Methods: MDCT scans of 12 subjects (6 healthy controls (HC), mean age ± standard deviation (SD): 62.16 ± 10.24 years, and 6 osteoporotic patients (OP), mean age ± SD: 65.83 ± 11.19 years) were included in the current study. Comprehensive FE models of the lumbar spine (5 vertebrae + 4 intervertebral discs (IVDs) + ligaments) were generated (L1–L5) and simulated. The coefficients of correlation (ρ) were calculated to investigate the relationship between FE-based FL and ROM parameters and bone mineral density (BMD) values of L1–L3 derived from MDCT (BMDQCT-L1-3). Finally, Mann–Whitney U tests were performed to analyze differences in FL and ROM parameters between HC and OP cohorts. (3) Results: Mean FE-based FL value of the HC cohort was significantly higher than that of the OP cohort (1471.50 ± 275.69 N (HC) vs. 763.33 ± 166.70 N (OP), p < 0.01). A strong correlation of 0.8 (p < 0.01) was observed between FE-based FL and BMDQCT-L1-L3 values. However, no significant differences were observed between ROM parameters of HC and OP cohorts (p = 0.69 for flexion; p = 0.69 for extension; p = 0.47 for lateral bending; p = 0.13 for twisting). In addition, no statistically significant correlations were observed between ROM parameters and BMDQCT- L1-3. (4) Conclusions: Clinical routine MDCT data can be used for patient-specific FE modeling of the whole lumbar spine. ROM parameters do not seem to be significantly altered between HC and OP. In contrast, FE-derived FL may help identify patients with increased osteoporotic fracture risk in the future.

Percutaneous cryoablation for clinical T3a renal cell carcinoma (< 7 cm) with segmental vein involvement or perinephric fat invasion based on preoperative evaluation of high-resolution multidetector computed tomography scan

PurposeTo retrospectively assess the feasibility, safety, renal function, technique efficacy rate, and survival of patients with clinical T3a renal cell carcinoma (RCC).Materials and methodsSixteen cryoablation sessions were performed in 14 patients (10 men; mean age, 69.8 ± 10.5 years; range, 49–90 years) with 14 clear cell T3a RCCs (mean, 3.3 ± 0.9 cm; range, 1.9–5.2 cm). One patient was on dialysis. Transcatheter arterial embolization was performed before cryoablation in 15 sessions. The primary endpoint was the technique efficacy rate. The secondary endpoints included feasibility, safety, renal function, and survival.ResultsCryoablation was technically successful in all RCC cases. In two RCCs, cryoablation was performed twice because of local tumor progression. No major adverse events were observed. All patients were alive without metastases, with a median follow-up of 45 months (6−93 months). Complete response was achieved by cryoablation in 11 RCCs (78.6%). The primary and secondary technique efficacy rates were 77.1% and 84.4% at 1 year, 57.9% and 73.9% at 3 years, and 57.9% and 73.9% at 5 years, respectively. One patient underwent dialysis given a total contralateral nephrectomy due to another RCC 1 month after initial cryoablation and a total ipsilateral nephrectomy 46 months after initial cryoablation due to local progression. Except for two dialysis patients, of the 12 patients with a median follow-up of 41 months (6–93 months), none were on dialysis.ConclusionCryoablation was safe and effective in T3a RCC, which mainly involved the renal venous branches and may represent an alternative treatment for inoperable patients.

Mid-term impact of underfilling and overfilling of the SAPIEN 3 balloon-expandable transcatheter aortic valve implantation on mortality and valve function.

At present, underfilling or overfilling the volume of the balloon-expandable transcatheter heart valve (THV) is generally utilized in transcatheter aortic valve implantation (TAVI). However, no research has assessed the clinical impact of filling volume variations of the current-generation SAPIEN 3 THV. We analyzed the clinical data of 331 patients who underwent TAVI with SAPIEN 3 at our institution. Post-procedural echocardiographic and multidetector computed tomography (MDCT) scan data and 3-year prognoses according to each filling volume were assessed. The procedural outcomes and 3-year mortality rates were comparable among the underfilling, nominal filling, and overfilling groups. For all THV sizes, the THV area evaluated on post-procedural MDCT scan increased stepwise along with an elevated filling volume, thereby covering a wide range of native annulus area. Compared with patients in the nominal filling and overfilling groups, those with 23-mm THVs in the underfilling group had a smaller effective orifice area (EOA) (1.38 [IQR: 1.18-1.56] vs. 1.57 [IQR: 1.41-1.84] vs. 1.58 [IQR: 1.45-1.71] cm2, P = 0.02) and a higher mean transvalvular gradient (13.6 [IQR: 11.0-15.7] vs. 12.1 [IQR: 9.0-14.9] vs. 12.0 [IQR: 8.1-14.8] cm2, P = 0.04). In conclusion, by adjusting the filling volume of SAPIEN 3 using THV with limited sizes, continuously distributed native annulus areas were covered. The underfilling implantation technique had a minimal negative effect on the valve function of 23-mm THVs only. In the entire cohort, the filling volume variations did not affect the mid-term prognosis negatively.

Assessment of Coronary Arteries Calcification in Diabetic Patients by using CT Calcium Score Technique

This study designed to define the role of computed tomography coronary angiography (CTA) in the diagnosis of patients with chest pain and suspected to have coronary artery disease (CAD) by measuring the calcium scoring in the coronary arteries (CAC) in patient with known diabetes and correlate the results with the (CTA) findings and other related variables. A descriptive analytical study for 84 patient with 36 diabetes and 48 patient with diabetes and hypertension examined using multi-detector computed tomography scanner MDCT64-Slice scanner (0.625 mm slices): 64 slice 0.625 mm collimation, table feed 10 mm/rotation, effective tube current 685 mAs at 120 kV. Pitch = 10/40 mm, collimation = 0.25 Average scan time = 5s, to scan the patient with coronary problems, detector array, fan beam shape, CT monitor for controlling scanning and processing. Cardiac trigger monitor with electrode leads (3000 TOSHEIBA) to monitor the heart rate, contrast injector (Medrao Toshiba-2ways) for flush contrast media to patient and VITREA SYSTYM (TOSHIBA) for diagnosis images and reconstruction and volume rendered purposes.(CAC) offers identifying the patients intended to have cardiac events, diagnosis of coronary arteries lesions and characterizing the plaque pattern .It is believable that measurements of calcium score will provide an acknowledged analytical radiological tool for the diagnoses of (CAD).

Role of ultrasonography and computed tomography in stomach and bowel diseases

Background-In this study we compared ultrasound with CT in detecting causes of Common stomach and bowel pathologies such as appendicitis, diverticulitis, volvulus in patients presenting at the department with acute abdominal pain in the majority of cases. Methods- A cross-sectional study was conducted in our institute from September 2019 to August 2021 following approval from the Ethical committee of the hospital. All clinically suspected lesions involving stomach and bowel patients included patients who were clinically evaluated at OPD &amp; the emergency department by the surgeon. All those who fulfilled the inclusion criteria were explained the purpose of the study. After clinical assessment, all consenting patients underwent ultrasound and computed tomography (CT) within a few hours of presentation.&#x0D; Results- A total of 100 patients with stomach and bowel disorders were studied using ultrasound and multidetector CT scan. 25 patients were diagnosed with appendicular pathologies, 25 cases with primary neoplasms, 18 were abdominal Koch’s, 17 were Crohn’s disease, 6 were ulcerative colitis, 4 were volvulus, 3 were diverticulitis, 2 were intussusception.Acute appendicitis was the most frequent finding seen in 23 patients. Ultrasound was diagnostic in all except one case.

Level-Specific Volumetric BMD Threshold Values for the Prediction of Incident Vertebral Fractures Using Opportunistic QCT: A Case-Control Study.

PurposeTo establish and evaluate the diagnostic accuracy of volumetric bone mineral density (vBMD) threshold values at different spinal levels, derived from opportunistic quantitative computed tomography (QCT), for the prediction of incident vertebral fractures (VF).Materials and MethodsIn this case-control study, 35 incident VF cases (23 women, 12 men; mean age: 67 years) and 70 sex- and age-matched controls were included, based on routine multi detector CT (MDCT) scans of the thoracolumbar spine. Trabecular vBMD was measured from routine baseline CT scans of the thoracolumbar spine using an automated pipeline including vertebral segmentation, asynchronous calibration for HU-to-vBMD conversion, and correction of intravenous contrast medium (https://anduin.bonescreen.de). Threshold values at T1-L5 were calculated for the optimal operating point according to the Youden index and for fixed sensitivities (60 – 85%) in receiver operating characteristic (ROC) curves.ResultsvBMD at each single level of the thoracolumbar spine was significantly associated with incident VFs (odds ratio per SD decrease [OR], 95% confidence interval [CI] at T1-T4: 3.28, 1.66–6.49; at T5-T8: 3.28, 1.72–6.26; at T9-T12: 3.37, 1.78–6.36; and at L1-L4: 3.98, 1.97–8.06), independent of adjustment for age, sex, and prevalent VF. AUC showed no significant difference between vertebral levels and was highest at the thoracolumbar junction (AUC = 0.75, 95%-CI = 0.63 - 0.85 for T11-L2). Optimal threshold values increased from lumbar (L1-L4: 52.0 mg/cm³) to upper thoracic spine (T1-T4: 69.3 mg/cm³). At T11-L2, T12-L3 and L1-L4, a threshold of 80.0 mg/cm³ showed sensitivities of 85 - 88%, and specificities of 41 - 49%. To achieve comparable sensitivity (85%) at more superior spinal levels, resulting thresholds were higher: 114.1 mg/cm³ (T1-T4), 92.0 mg/cm³ (T5-T8), 88.2 mg/cm³ (T9-T12).ConclusionsAt all levels of the thoracolumbar spine, lower vBMD was associated with incident VFs in an elderly, predominantly oncologic patient population. Automated opportunistic osteoporosis screening of vBMD along the entire thoracolumbar spine allows for risk assessment of imminent VFs. We propose level-specific vBMD threshold at the thoracolumbar spine to identify individuals at high fracture risk.

Effect of different contrast medium injection protocols for analysis of hepatic computed tomography perfusion in healthy dogs.

To evaluate the hepatic CT perfusion (CTP) for determining the appropriate protocol for the dual-input maximum-slope model in dogs. 5 healthy dogs. Each dog underwent CTP with different contrast medium administration protocols. Combinations of three different injected doses of iohexol (450, 600, and 750 mg/kg) and injection durations (5, 10, and 15 seconds) were used. The CT values at the aorta, portal vein, and hepatic parenchyma were measured to create a time-density curve, and CTP parameters were measured simultaneously on each hepatic lobe using a 320-row multidetector CT scanner. The maximum peak enhancement at the aorta, portal vein, and hepatic parenchyma was greater with the 750-mg/kg dose than with the 450-mg/kg dose. With an injection duration of 15 seconds, the aortic enhancement peak was less, and the arrival time at the aortic enhancement peak was longer compared to that with a 5-second injection duration. The CTP parameters in the caudate process of the caudate lobe and left lateral lobe differed with different injection durations. The CTP parameters in the caudate process of the caudate lobe, left lateral lobe, and right lateral lobe differed with varying injected doses. Our study demonstrated that rapid administration of the contrast medium was required for quantitative analysis of hepatic CTP in healthy dogs. The CTP parameters differed with respect to the contrast medium administration protocol, and it was necessary to administer the contrast medium within a fixed duration and at a fixed dose to evaluate CTP correctly.

Recent Advances in Coronary Computed Tomography Angiogram: The Ultimate Tool for Coronary Artery Disease.

The emerging technologies in multidetector computed tomography scanners gave the ability to image coronary arteries in a single heartbeat, at a higher quality, and low radiation dose. Furthermore, incorporating artificial intelligence and machine learning into image processing and interpretation have extended the use for coronary computed tomography angiogram (CCTA) and its applications. In this review, we will explore the recent evidence and advances supporting CCTA to become the ultimate tool for coronary artery disease. Results from the EVINCI, ISCHEMIA, SCOT-HEART, and PROMISE showed that CCTA is better in patients' risk stratification and in detecting subclinical atherosclerosis, resulting in earlier interventions and lesser events. Additionally, CCTA gave us a closer look on atherosclerotic disease by identifying different type of plaque and their clinical significance. Furthermore, FFRCT is a notable example of incorporating artificial intelligence into CCTA. This technology helped us to accurately and non-invasively identify flow limiting lesions, guiding revascularization. As a result of the recent evidence, CCTA have made its way into the chest pain guidelines all over the world. Moreover, CCTA have the potential to revolutionize our understanding and standards in screening, preventing, and managing heart disease.

The left-sided aortic arch variants: prevalence meta-analysis of imaging studies.

To estimate the prevalence of the left-sided aortic arch (LSAA) variants, and the effect of possible moderators on variants' detection. A systematic online literature search was conducted. The pooled prevalence with 95% confidence intervals was estimated for the typical and atypical branching patterns to compare the overall proportions of different variants. Meta-regression analyses were performed to investigate the effect of the subjects' gender and geographical region, and the multidetector computed tomography (MDCT) scanner's technology on the estimated prevalence. In total, 18,075 cases from 23 imaging studies were included and 33 different LSAA variants were detected. The estimated heterogeneity was statistically significant. Based on the estimated prevalence, approximately 77% of the population is expected to have the typical branching anatomy with sequence brachiocephalic trunk-left common carotid artery-left subclavian artery, and 23% variant branching patterns. Approximately 71%, 23%, 2%, and 0.1% of the atypical populations are expected to have two, four, three, and five emerging branches, respectively. The meta-regression analyses showed that the number of detector rows of the MDCT scanner, and the subjects' geographical region are statistically significant moderators of the estimated prevalence. The current findings indicate that the prevalence of the LSAA variant branching anatomy is significantly affected by the subjects' geographical region and the MDCT scanner's technological improvement, with the advanced scanners to facilitate the detection of the aortic arch variants. However, due to the heterogeneity among studies, further research is required.

Insulinoma-Accurate Preoperative Localization Is the Key to Management: An Initial Experience.

Insulinoma is the commonest functioning pancreatic neuroendocrine tumor. The only curative treatment is surgical excision after preoperative localization. A retrospective analysis of nine patients (February 2017-June 2020), 2 males and 7 females, was done for clinical presentation, biochemistry, localization methods, intraoperative findings, postoperative outcome, histopathology reports, and follow-up. Techniques for localization of the tumor were pancreatic protocol triple-phase multi-detector computed tomography (MDCT), endoscopic ultrasound (EUS), Ga 68 DOTANOC PET-CT, and Ga 68 NOTA-exendin-4 PET-CT (GLP1R scan). The mean age was 38 (range 20-68) years and mean duration of symptoms 34 (range 8-120) months, and symptoms of Whipple's triad were present in all cases after a supervised 72-h fast. MDCT localized tumor in 8/9 cases. EUS before MDCT in one patient had also localized tumors. Ga 68 DOTANOC PET-CT detected tumor in 2/4 patients. In one patient, MDCT or DOTANOC PET scan could not localize tumor; GLP1R scan localized tumor accurately. Two patients had associated MEN1 syndrome. All 9 patients underwent surgical resection (four open and five laparoscopic) of tumor-enucleation (3), distal pancreatectomy with splenectomy (3), and pancreatoduodenectomy (PD) (3). The last four procedures and all three enucleations were laparoscopic. Five patients developed postoperative pancreatic fistula (POPF), only one grade B which required percutaneous drain placement. One patient, who had initial open enucleation, developed hypoglycemia after 48h; PD was performed. All patients were cured and all, except one (who died of upper GI bleed), were alive and disease-free during a mean follow-up of 26 (range 2-41) months. Preoperative localization of insulinoma is important and decides the outcome of surgery in terms of cure. MDCT can localize tumors in most patients; the last resort for localization is the GLP1R scan. Laparoscopic procedures are equally effective compared to open surgery. Considering the benign nature of the disease, enucleation is the procedure of choice.

Impact of multidetector computed tomography scan parameters, novel reconstruction settings, and lung nodule characteristics on nodule diameter measurements: A phantom study.

Novel CT reconstruction techniques strive to maintain image quality and processing efficiency. The purpose of this study is to investigate the impact of a newer hybrid iterative reconstruction technique, Adaptive Statistical Iterative Reconstruction-V (ASIR-V), in combination with various CT scan parameters on the semi-automated quantification using various lung nodules. A chest phantom embedded with eight spherical objects was scanned using varying CT parameters such as tube current and ASIR-V levels. We calculated absolute percentage error (APE) and mean APE (MAPE) using differences between the semi-automated measured diameters and known dimensions. Predictive variables were assessed using a multivariable general linear model. The linear regression slope coefficients (β) were reported to demonstrate effect size and directionality. The APE of the semi-automated measured diameters was higher in ground-glass than solid nodules (β=9.000, p<0.001). APE had an inverse relationship with nodule diameter (mm; β=-3.499, p<0.001) and tube current (mA; β=-0.006, p<0.001). MAPE did not vary based on the ASIR-V level (range: 5.7%-13.1%). Error is dominated by nodule characteristics with a small effect of tube current. Regardless of phantom size, nodule size accuracy is not affected by tube voltage or ASIR-V level, maintaining accuracy while maximizing radiation dose reduction.

Anatomical Variations of Vermiform Appendix on Plain MDCT and Its Association with Acute Appendicitis in Adult Urban Population of Karachi, A Tertiary Care Hospital Experience

Objective: To evaluate the anatomical positions of vermiform appendix and its association with acute appendicitis on Multidetector computed tomography (MDCT). Study design and setting: A cross sectional study based on hospital database was carried out in Department of Anatomy in collaboration with Department of Radiology, Liaquat National Hospital. Methodology: A total of three hundred and six 306 adult urban patients CT axial images were evaluated retrospectively over period of 6 months from March 2021 to August 2021 who had abdominal MDCT scan for acute abdomen after getting approval from ethical committee to find out anatomical variations of position of vermiform appendix in a tertiary care hospital among adult urban Karachi population and its association with appendicitis. Data was analyzed using SPSS version 25. All categorical variables were summarized as frequencies and percentages. Result: In present study 159(52%) were males and 147(48%) were females with mean age of 32.97 years. The subcecal anatomical position of vermiform appendix on MDCT was most common n=85(27.8%), followed by postileal n=78(25.5%), pelvic n=61(19.9%), postcecal n= 36(11.8%), preileal n=29(9.5%), ectopic n=17(5.6%). The association between appendicitis with anatomical position of vermiform appendix and age was analyzed by chi- square and was statistically significant (p =0.05). There was no significant association between position of vermiform appendix on MDCT and gender. Conclusion: The subcecal position of vermiform appendix is most common on MDCT and the postileal position was more frequent in the inflamed group of vermiform appendix

Estimating the optimal entry point of the antegrade femoral nailing: Previous and novel morphometric measurements.

This anatomical study aimed to investigate the possible relationships between the proximal femur parameters and verify the optimal entry point in line with the medullary canal. Both in single image series and 3D-MPR views, 63 femur bones were evaluated. One-millimeter multidetector computed tomography scans were collected and assessed by OsiriX-Lite version 8 and Horos v3.3.5. Entry point locations, projected and true femoral neck-shaft, anteversion, and newly defined nail entrance angles were measured. The entry points of 16 femurs were placed at the tip of the greater trochanter, and the remaining 47 femurs were in the trochanteric fossa (i.e., piriformis fossa). Thirty-three of the entry points found in the trochanteric fossa were overlapped by the greater trochanter. When the parameters of the right and left sides were compared, it was found that; projected neck angle, nail entrance angle, and the differences between true neck angle and nail entrance angle were found significantly different. The relationship between nail entrance angle and entry point localization was assessed, and the probability of the entry point being at the tip of the greater trochanter is 63 times greater when the NEA is below 90. This study has demonstrated that the ideal entry point for straight nails, which is based on the anatomic axis of the femur, is found mainly at the trochanteric fossa, and the greater trochanter overlapped 70.21% of them. Level IV, Diagnostic Study.

Risk of conduction disturbances following different transcatheter aortic valve prostheses: the role of aortic valve calcifications.

OBJECTIVESTo assess the impact of prosthesis choice and aortic valve calcifications on the occurrence of conduction disturbances after transcatheter aortic valve implantation (TAVI).METHODSWe retrospectively analyzed the preoperative clinical characteristics, electrocardiograms, contrast-enhanced multidetector computed tomography scans and procedural strategies of patients who underwent TAVI in our center between January 2012 and June 2017. Quantification of calcium volume was performed for each aortic cusp above (aortic valve) and below (left ventricular outflow tract, LVOT) the basal plane. Multivariate analysis was performed to evaluate risk factors for the onset of new bundle branch block (BBB), transient and permanent atrioventricular block (tAVB, pAVB).RESULTSA total of 569 patients were included in the study. Six different prostheses were implanted (Edwards Sapien XT, n = 162; Edwards Sapien 3, n = 240; Medtronic CoreValve, n = 27; Medtronic CoreValve Evolut R, n = 21; Symetis Acurate, n = 56; Symetis Acurate neo, n = 63). The logistic regression analysis for BBB showed association with baseline left anterior hemiblock. The logistic regression for tAVB, found the prior valvuloplasty and the balloon post-dilatation associated with the outcome. Baseline left and right BBB, degree of oversizing, and LVOT calcification beneath the non-coronary cusp were associated with pAVB. Neither the prosthesis model, nor the use of a self-expandable prosthesis showed statistical significance with the above-mentioned outcomes on univariate analysis. CONCLUSIONSLVOT calcification beneath the non-coronary cusp, baseline left anterior hemiblock, right BBB, balloon post-dilatation, prior valvuloplasty and oversizing are independently associated with postprocedural conduction disturbances after TAVI. Use of a self-expandable prosthesis may show a lower incidence of AVB, if applied in lower calcified aortic valves.