Tomography Scan Research Articles

Diagnostic problems of rare diseases - amyloidosis. A case report

The presented case study focuses on the complexities and challenges in diagnosingone of the forms of amyloidosis, where abnormal protein (amyloid) deposits in variousorgans and tissues lead to affection of many organs, especially the heart, kidneys, liver,spleen, and occasionally the central nervous system. Its aetiology remains largely unknown,making diagnosis and treatment particularly challenging.This report details the case of an 88-year-old patient, disabled for months (with amodified Rankin Scale score of 4), who presented to the Neurology Department with suddenright limb paresis and speech disorders. Initial assessments indicated suggested ischemicstroke, and patients received thrombolysis. Further laboratory tests and imaging, includingserum protein electrophoresis and computer tomograph (CT) scans, suggested transthyretinamyloidosis (ATTR), which was later confirmed through genetic testing.This case underscores the rapid, multi-organ progression of amyloidosis and itsdevastating impact, highlighting the necessity for early diagnosis and a multidisciplinarytreatment approach.Despite ongoing research, the pathogenesis of amyloidosis remains elusive, andcurrent treatment options are primarily symptomatic. This study aims to shed light on thediagnostic difficulties and the urgent need for timely intervention in amyloidosis cases.

Three-dimensional analysis of bone site grafting on the upper extremity on computed tomography scans.

To perform a quantitative analysis of the amount of cancellous bone in the distal radius and olecranon process by segmentation of computed tomographic scans. As a secondary analysis, the bone density by Hounsfield units was evaluated at the same sites. Computed tomography angiography images of the upper extremity were analyzed using 3-D Slicer™ medical imaging software. Bone volume (cm3) and density (Hounsfield units) from the cancellous bone between the distal radius and the olecranon process were compared by creating an advanced three-dimensional model. The images were analyzed in duplicate, and an intraclass correlation was performed to assess measurement consistency. Twenty subjects were included. A total volume of 5.01 ± 1.21cm3 and 5.81 ± 1.61cm3 for the distal radius and the olecranon process (p < .0001), respectively, was found. Regarding Hounsfield units, the density of the olecranon process was 303.1 ± 73.26, and the distal radius was 206.5 ± 63.73 (p < .0001). All intraclass correlation coefficients were >0.992. These results suggest that the olecranon process has a greater volume and a higher bone mineral density than the distal radius. With these results, the surgeon will have the ability to decide the quantity and quality of bone grafts according to the surgical procedure.

Congruent Concavity Restoration of the Reconstructed Glenoid After the Latarjet Procedure: Compensation for the Position of the Graft.

Few clinical studies have addressed concavity restoration by natural remodeling after a Latarjet procedure. This study investigated the fibrous tissue and osseous remodeling of the reconstructed glenoid and concavity restoration after a Latarjet procedure using postoperative computed tomographic arthrography (CTA). This retrospective study included 31 patients who underwent immediate postoperative computed tomographic (CT) scanning followed by CTA at 6 months postoperatively. We investigated whether fibrous tissue was newly created over the graft, whether the created fibrous tissue restored the congruity of the articular surface and the osseous remodeling of the graft to the glenoid level (whether the osseous portion of the graft was remodeled flush to the glenoid level) and the concavity of the glenoid using the radius of a best-fit circle on the articular surface, and the relationship between the amount of created fibrous tissue and the position of the graft. In all patients, the fibrous tissue on the graft yielded a smooth articular surface, as revealed by the CTA. The mean radius of the entire glenoid, including the transferred graft, was significantly smaller (p = 0.010) at 33.2 ± 8.5 mm than that of the glenoid posterior to the osseous step-off at 37.6 ± 9.4 mm, which is presumed to be the glenoid before the surgical procedure. Despite the congruity of the articular surfaces due to fibrous tissue seen in the CTA, 14 (45%) of 31 patients showed a subchondral osseous step-off on either the medial side or the lateral side in the immediate postoperative CT scans. However, through osseous remodeling, 8 of the 10 grafts with a lateral step-off and 2 of the 4 grafts with a medial step-off converted to a flush position. The position of the step-off was correlated with the thickness of the fibrous tissue, with a tendency for thicker tissue in cases of a step-off on the medial side (p = 0.014). Fibrous tissue formation plus remodeling of the transferred graft resulted in the restoration of a congruent concavity after a Latarjet procedure by compensating for initially non-flush positioning of the graft. However, due to the small sample size in our study, clinical outcomes could not be correlated with radiographic findings, and our recommendation is to continue placing the graft as anatomically as possible. Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Rapid, high-contrast, and steady volumetric imaging with Bessel-beam-based two-photon fluorescence microscopy.

Two-photon fluorescence microscopy (TPFM) excited by Gaussian beams requires axial tomographic scanning for three-dimensional (3D) volumetric imaging, which is a time-consuming process, and the slow imaging speed hinders its application for in vivo brain imaging. The Bessel focus, characterized by an extended depth of focus and constant resolution, facilitates the projection of a 3D volume onto a two-dimensional image, which significantly enhances the speed of volumetric imaging. We aimed to demonstrate the ability of a TPFM with a sidelobe-free Bessel beam to provide a promising tool for research in live biological specimens. Comparative in vivo imaging was conducted in live mouse brains and transgenic zebrafish to evaluate the performance of TPFM and Bessel-beam-based TPFM. Additionally, an image-difference method utilizing zeroth-order and third-order Bessel beams was introduced to effectively suppress background interference introduced by sidelobes. In comparison with traditional TPFM, the Bessel-beams-based TPFM demonstrated a 30-fold increase in imaging throughput and speed. Furthermore, the effectiveness of the image-difference method was validated in live biological specimens, resulting in a substantial enhancement of image contrast. Importantly, our TPFM with a sidelobe-free Bessel beam exhibited robustness against axial displacements, a feature of considerable value for in vivo experiments. We achieved rapid, high-contrast, and robust volumetric imaging of the vasculature in live mouse brains and transgenic zebrafish using our TPFM with a sidelobe-free Bessel beam.

State-of-the-art multimodal scanning hard X-ray imaging and tomography sheds light at multiple length-scales on biomineralization related processes

Biomineralization is a widespread process among living organisms, playing a significant role in the formation and preservation of geological structures, biogeochemical cycles, regulation of ocean chemistry, and carbon sequestration. Moreover pathological biomineralization has a huge impact on human health. The growth of biominerals provides a rich area for research at multiple length-scales since they have controlled hierarchical structures from nano-to macroscopic scales. Here, we provide an overview on the potentials of the state-of-the-art scanning hard X-ray imaging and tomography methods developed at the NANOSCOPIUM beamline at Synchrotron Soleil in such studies. Multimodal scanning imaging provides simultaneous information on the elemental composition by X-ray fluorescence (XRF) spectrometry, on the sample morphology by absorption contrast imaging, on the crystalline structure by X-ray diffraction, and on the luminescence characteristics by X-ray Excited Optical Luminescence. As illustrated through diverse research cases about biomineralization in stromatolites and pathological calcification, such a versatile portfolio of X-ray imaging techniques provides unique complementary information to conventional laboratory techniques on biominerals and the underlying mineral precipitation processes.

Isolated greater trochanter fractures of the native hip: Is magnetic resonance imaging needed?

Background: Isolated greater trochanter fractures represent a subset of hip fractures for which diagnostic work-up and treatment algorithms can vary. Magnetic resonance imaging has been described as the definitive method of evaluating fracture extension into the intertrochanteric region. While prophylactic fixation for those with fracture extension may prevent the propagation of the injury, treatment debates remain. This study aimed to assess adherence to protocols at our institution and evaluate outcomes in those whose care deviated from protocol. Methods: In a retrospective analysis, adult patients (≥18 years old) presenting with a greater trochanter fracture over a 7-year period (2015–2021) were identified. Patients were excluded if the injury was periprosthetic, had a ballistic mechanism, or had any concomitant fractures of the femoral head, neck, or shaft identified on plain radiographs. Patient demographics, comorbidities, treatment, and outcomes were tabulated via chart review. Results: In total, 57 isolated greater trochanter fracture patients were included. Of these, 52 patients (91%) had computed tomographic scans, yet only 41 patients (72%) had magnetic resonance imaging completed. In total, 10 of the 41 (24%) patients with magnetic resonance imaging showed &lt;50% fracture line extension, and all of these patients were treated nonoperatively. In contrast, 24 of 41 magnetic resonance imaging patients (59%) showed &gt;50% fracture line extension in both coronal and axial planes, of which 14 (58%) were treated operatively. However, the 10 nonoperative patients with significant fracture extension showed no increased hospital length-of-stay or fracture extension upon follow-up. Conclusions: Our study showed that institutional protocol for diagnostic workup and treatment evaluation for isolated greater trochanter fractures is not consistently followed. However, patients who deviated from treatment protocol showed no elevated risks of fracture propagation. Our study questions the need for magnetic resonance imaging in all isolated greater trochanter fractures, and suggests that protocols be revisited to ensure that workup is optimal for patients and costeffective for the healthcare system itself.

In vivo real-time positron emission particle tracking (PEPT) and single particle PET

Positron emission particle tracking (PEPT) enables 3D localization and tracking of single positron-emitting radiolabelled particles with high spatiotemporal resolution. The translation of PEPT to the biomedical imaging field has been limited due to the lack of methods to radiolabel biocompatible particles with sufficient specific activity and protocols to isolate a single particle in the sub-micrometre size range, below the threshold for capillary embolization. Here we report two key developments: the synthesis and 68Ga-radiolabelling of homogeneous silica particles of 950 nm diameter with unprecedented specific activities (2.1 ± 1.4 kBq per particle), and the isolation and manipulation of a single particle. We have combined these developments to perform in vivo PEPT and dynamic positron emission tomography (PET) imaging of a single radiolabelled sub-micrometre size particle using a pre-clinical positron emission tomography/computed tomography scanner. This work opens possibilities for quantitative assessment of haemodynamics in vivo in real time, at the whole-body level using minimal amounts of injected radioactive dose and material.

SUCCOR morbidity: complications in minimally invasive versus open radical hysterectomy in early cervical cancer

ObjectiveThe aim of this study was to compare the incidence of intra-operative and post-operative complications in open and minimally invasive radical hysterectomy for patients with early-stage cervical cancer.MethodsData were collected...

Comparative study of two retrograde locked intramedullary nail designs for ankle arthrodesis: A finite element analysis.

Ankle arthrodesis is the gold standard for treatment of end-stage arthritis. The goal of ankle arthrodesis is to obtain bony union between the tibia and the talus. Retrograde intramedullary nailing is typically reserved for ankle and subtalar joints arthrodesis. The purpose of this study is to evaluate the effect of two different materials, two locking pin configurations and two nail designs of a retrograde locked intramedullary nail used for ankle arthrodesis. Using the finite element analysis, a numerical study of ankle arthrodesis was developed to evaluate the effect of materials: TI-6Al-4V and stainless steel AISI 316 LVM; two locking pin configurations: five and six pins, on two intramedullary nails: Ø10 × 180 mm and Ø11 × 200 mm. A model of a healthy foot was created from tomographic scans. It was found that the mechanical stimulus required to achieve bone fusion were higher for Ø10 × 180 nails (6.868 ± 0.047) than the Ø11 × 200 nails (5.918 ± 0.047; p < 0.001; mean ± SEM). We also found that six-pin configuration had a higher mechanical stimulus (6.470 ± 0.047) than the five-pin configuration (6.316 ± 0.046; p = 0.020). Similarly, it was higher for titanium (6.802 ± 0.047) than those for stainless steel (5.984 ± 0.046; p < 0.001). Finally, the subtalar zone presented higher values (7.132 ± 0.043) than the tibiotalar zone (5.653 ± 0.050; p < 0.001). The highest mechanical stimulus around the vicinity of tibiotalar and subtalar joint was obtained by Ø10 × 180 nails, made of titanium alloy, with 6P.

Autosomal dominant polycystic kidney disease with ectopic unilateral multicystic kidney: a case report

BackgroundAutosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disorder and the fourth cause of death of end-stage renal disease. The disease has a prevalence of 1:400–1:1000 accounting for 10% of patients on dialysis. In most ADPKD patients, bilateral kidneys are similarly affected, with numerous fluid-filled cysts arising from different nephron segments. Only a few cases of ADPKD with ectopic unilateral multicystic kidney have been reported. It has been observed that the deterioration of their kidney function seemed to be quicker than their age- and sex-matched controls and siblings especially when the ectopic kidney is dysplastic.Case presentationWe report a case of a 46-year-old Ghanaian male patient who presented with left flank pain and hematuria with high BP and deranged renal function. Abdominal ultrasonography showed both kidneys to be larger than normal and had multiple cysts of varying sizes with the right kidney located in the right iliac fossa. Follow up Abdominopelvic computer tomographic scan (CT–Scan) without contrast showed enlarged kidneys with the renal parenchyma replaced by innumerable cyst of varying sizes. The right kidney was ectopically located in the right aspect of the pelvis. A diagnosis of ADPKD with right pelvic ectopic multicystic kidney was made. He was put on antihypertensives, analgesia for the left flank pain and to have follow up at the urology and nephrology departments.ConclusionIn most ADPKD patients, bilateral kidneys are similarly affected. Only a few cases of ADPKD with ectopic unilateral multicystic kidney have been reported. It has been observed that the deterioration of their kidney function seemed to be quicker than their age- and sex-matched controls and siblings especially when the ectopic kidney is dysplastic.

Brain structure and function: a multidisciplinary pipeline to study hominoid brain evolution.

To decipher the evolution of the hominoid brain and its functions, it is essential to conduct comparative studies in primates, including our closest living relatives. However, strong ethical concerns preclude in vivo neuroimaging of great apes. We propose a responsible and multidisciplinary alternative approach that links behavior to brain anatomy in non-human primates from diverse ecological backgrounds. The brains of primates observed in the wild or in captivity are extracted and fixed shortly after natural death, and then studied using advanced MRI neuroimaging and histology to reveal macro- and microstructures. By linking detailed neuroanatomy with observed behavior within and across primate species, our approach provides new perspectives on brain evolution. Combined with endocranial brain imprints extracted from computed tomographic scans of the skulls these data provide a framework for decoding evolutionary changes in hominin fossils. This approach is poised to become a key resource for investigating the evolution and functional differentiation of hominoid brains.

The impact of diabetes and subclinical hypothyroidism association with coronary artery calcium: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

We aimed to analyze the association of diabetes and subclinical hypothyroidism with subclinical atherosclerosis measured by coronary artery calcium (CAC) in the baseline of the ELSA-Brasil study. CAC was measured using a 64-detector computed tomographic scanner. The association of CAC > 0 was presented as an odds ratio (OR) and 95% confidence intervals (95%CI) in logistic models and as β (95%CI) in linear models after multivariable adjustment for confounders. We analyzed 3,809 participants (mean-age (SD) 50.5 (8.8); 51.7% women). In the main analysis, we did not find an association of diabetes and subclinical hypothyroidism with CAC. However, in stratified analysis according to age strata, we found no significative interaction terms, an important heterogeneity between the groups, with the younger age strata showing an association of the group with both diseases and CAC > 0 (OR 7.16; 95%CI, 1.14; 44.89) with a wide but significative 95%CI, suggesting that the smaller number of participants in the younger group may influence the results. Our findings also showed an association of CAC > 0 and log (CAC+1) with diabetes in logistic (OR, 1.31; 95%CI, 1.05-1.63) and linear models (β, 0.24, 0.16, 0.40), respectively. Diabetes was independently associated with CAC > 0 in linear models. In conclusion, our results showed a great heterogeneity in stratified analysis based on age in the younger age strata. Although we found no significant interaction factors, the smaller sample size for the analysis may influence the negative findings.

Adults with metabolically healthy overweight or obesity present more brown adipose tissue and higher thermogenesis than their metabolically unhealthy counterparts

There is a subset of individuals with overweight/obesity characterized by a lower risk of cardiometabolic complications, the so-called metabolically healthy overweight/obesity (MHOO) phenotype. Despite the relatively higher levels of subcutaneous adipose tissue and lower visceral adipose tissue observed in individuals with MHOO than individuals with metabolically unhealthy overweight/obesity (MUOO), little is known about the differences in brown adipose tissue (BAT). This study included 53 young adults (28 women) with a body mass index (BMI) ≥25kg/m2 which were classified as MHOO (n=34) or MUOO (n=19). BAT was assessed through a static 18F-FDG positron emission tomography/computed tomography scan after a 2-h personalized cooling protocol. Energy expenditure, skin temperature, and thermal perception were assessed during a standardized mixed meal test (3.5h) and a 1-h personalized cold exposure. Body composition was assessed by dual-energy x-ray absorptiometry, energy intake was determined during an ad libitum meal test and dietary recalls, and physical activity levels were determined by a wrist-worn accelerometer. Participants with MHOO presented higher BAT volume (+124%, P=0.008), SUVmean (+63%, P=0.001), and SUVpeak (+133%, P=0.003) than MUOO, despite having similar BAT mean radiodensity (P=0.354). In addition, individuals with MHOO exhibited marginally higher meal-induced thermogenesis (P=0.096) and cold-induced thermogenesis (+158%, P=0.050). Moreover, MHOO participants showed higher supraclavicular skin temperature than MUOO during the first hour of the postprandial period and during the cold exposure, while no statistically significant differences were observed in other skin temperature parameters. We observed no statistically significant differences between MHOO and MUOO in thermal perception, body composition, outdoor ambient temperature exposure, resting metabolic rate, energy intake, or physical activity levels. Adults with MHOO present higher BAT volume and activity than MUOO. The higher meal- and cold-induced thermogenesis and cold-induced supraclavicular skin temperature are compatible with a higher BAT activity. Overall, these results suggest that BAT presence and activity might be linked to a healthier phenotype in young adults with overweight or obesity. See acknowledgments section.

Structural and torque changes in implant components of different diameters subjected to mechanical fatigue

ObjectivesTo evaluate torque maintenance and structural damage in implant components of different diameters subjected to a fatigue challenge. MethodsThirty 10-mm-long, morse taper connection, titanium dental implants and their corresponding one-piece abutments were divided into three groups (n = 10) according to implant diameter: 4.3 mm (I4.3), 3.5 mm (I3.5), and 2.9 mm (I2.9). The implants were placed into a load-bearing fixture simulating bone tissue (modified G10), and the abutments were screwed into the implants to a final torque of 20 Ncm for the I4.3 and I3.5 and 15 Ncm for I2.9. The torque was secured by a digital torque meter. Cone-beam computed tomography (CBCT) scans were acquired and post-processed (e-Vol DX software) for all implant/abutment sets before and after subjecting them to fatigue in 37 °C distilled water (2 million cycles, constant load and frequency). The removal torque was measured using the same digital torque meter to calculate the difference in torque before and after fatigue. ResultsI2.9 showed substantial structural deformation compared with the other implant diameters (I3.5 and I4.3). However, the experimental groups did not show statistical differences for abutment loosening. SignificanceImplants smaller than 3.5 mm in diameter have a higher probability of structural deformation than standard-diameter implants. The association between tomographic scans and e-Vol DX software showed satisfactory consistency with the direct assessment using the digital torque meter, offering an additional tool to evaluate implant component loosening and structural deformations.

Biomimetic dental implant production using selective laser powder bed fusion melting: In-vitro results

Instead of a textured surface with irregular pore size and distribution as in conventional dental implants, the use of lattice structures with regular geometric structure and controlled pore size produced by selective laser powder bed fusion melting (LPDF) technique will provide more predictable and successful results regarding osseointegration and mechanics. In this study, biomimetic dental implants with 2 different pore designs were fabricated by LPDF technique and compared with conventional dental implants in terms of surface characterization and resistance to biomechanical forces. Finite element analysis, scanning electron microscopy, computed micro tomography scanning, ISO 14801 tests and detork tests were used for the comparison. The tested biomimetic implants were found to be as durable as conventional implants in terms of mechanical strength and detork values. They were also found to be 40–60% more advantageous than conventional dental implants with respect to surface area and volume. As a result, it was concluded that biomimetic dental implants with sufficient mechanical strength and complex surface geometries can be made as designed without changing the reliable base material and can be produced using a different manufacturing method.

Bilateral Microtia in a Female Infant: An Uncommon Congenital Ear Abnormality

Abstract Microtia–anotia is a spectrum of congenital anomalies of the auricle ranging from mild structural abnormality of the ear to complete absence of the ear (anotia). The condition is bilateral in 15% of cases, the right side being more commonly affected than the left in unilateral cases. The condition is of public health importance in part due to the psychological sequel, including the stigma associated with malformed ears and the burden of undergoing multiple surgeries for reconstruction. We present a case of a 39-day-old female child who presented to the hospital on account of deformed external ears and the absence of external ear opening noticed at birth. The role of imaging in these patients, particularly high-resolution computed tomographic (CT) scan, cannot be overemphasized for appropriate surgical intervention. A case of bilateral congenital microtia diagnosed on CT scan is thus presented. Bilateral congenital microtia is rare congenital malformations. The present report demonstrates the classic imaging features as seen on computed tomography which are indispensable for subsequent surgical intervention.

ResNeXt Deep Learning Model Based Transmission Image Reconstruction of Tomographic Gamma Scanning with Array Detectors

ResNeXt Deep Learning Model Based Transmission Image Reconstruction of Tomographic Gamma Scanning with Array Detectors

Permeability measurement of a 3D-printed AlSi10Mg porous medium: comparisons between first results with different experimental and numerical techniques

In this work, the permeability of a 3D-printed, AlSi10Mg porous medium, with porosity ε = 0.3 and an effective pore radius of 48 μm, developed to operate as wick in a sinter-like heat pipe, has been investigated by means of two different experimental approaches, and of two different numerical methods. The two experimental methods are the capillary rise tests, from which permeability was estimated by fitting the theoretical capillary rise curve to the experimental data, and the direct measurement of the the mass flow rate across the porous sample at an imposed pressure difference. The numerical simulations were performed too using two different approaches and software tools, namely, Lattice-Boltzmann with Palabos, and Finite-Volumes with OpenFOAM. In both cases, the simulation domain was reconstructed from a micro-computer aided tomographic scan of a porous medium sample. Preliminary simulations were run on a simple configuration, both to check simulation setup and validate results, and mesh independence was assessed. Then, pressure-driven and velocity-driven simulations of an incompressible fluid flow across the domain were performed, from which the permeability was estimated using Darcy and Darcy-Forchheimer equations. The results show that the methods, while not in complete agreement, provide a useful estimate. The numerical methods also complement the information given by the experimental techniques by highlighting the flow paths, and allow to analyze scenarios of increased and decreased porosity.

An anatomical study of the subarachnoid space surrounding the trigeminal ganglion in horses-in preparation for a controlled glycerol rhizotomy in equids.

Equine trigeminal-mediated headshaking is a painful neuropathic disorder comparable to trigeminal neuralgia in humans. The selective destruction of pain fibers within the trigeminal ganglion, called rhizotomy, is the surgical treatment of choice for idiopathic trigeminal neuralgia refractory to medical treatment in humans. The human trigeminal ganglion is enclosed by a dural recess called the Meckel's or trigeminal cave, in which the ganglion is surrounded by a cerebrospinal fluid (CSF)-filled subarachnoid space. During glycerol rhizotomy, glycerol is percutaneously injected in this CSF-filled space. Until now, information about the anatomy of the dural recess and the subarachnoid space surrounding the trigeminal ganglion is lacking in horses. The aim of this study was to explore if a CSF-filled subarachnoid space around the trigeminal ganglion exists in horses. Six equine cadaver heads were investigated for CSF accumulation around the ganglion with a 3 Tesla MRI. After anatomical dissection to expose the trigeminal root, a polymer-based radiopaque contrast agent was injected through the porus trigeminus into the subarachnoid space (cisternography). The exact delineation and the volume of the contrast agent accumulation were determined on subsequent micro-computed tomographic scans and segmentation. Finally, the distribution of the contrast agent within the subarachnoid space was examined histologically in three specimens. In all 12 specimens included in this study, the trigeminal ganglion was surrounded by a subarachnoid space forming a trigeminal cistern. The mean volume of the trigeminal cave in this study was 0.31 mL (±SD: 0.11 mL). Distribution of the contrast agent along the peripheral nerves (i.e., ophthalmic, maxillary and/or mandibular nerve) was observed in 7 out of 12 specimens. A subarachnoid space surrounding the trigeminal ganglion exists in the horse and could be targeted for glycerol rhizotomy in horses suffering from trigeminal-mediated headshaking. However, the clinical relevance of contrast agent distribution along the peripheral nerves remains to be assessed.

Evaluation of Canal Transportation and Centering Ability of RaCe and Af f-one Systems by Cone-beam Computed Tomography: An in Vitro Study.

Rotary systems have made significant advances to improve their root canal preparation efficacy. These instruments can properly preserve the root canal anatomy and morphology. The present in vitro study aimed to compare canal transportation and centering ability of RaCe and Af f-one systems using cone-beam computed tomography. Thirty-six mandibular molars were included. The samples were randomly assigned to two groups (n=18): group 1, RaCe, and group 2, Af f-one. Canal preparation was conducted using the respective files according to the manufacturers' instructions. The cone-beam computed tomographic scanning of the samples was performed before and after preparation. The data were analyzed by using two-way ANOVA. In both the RaCe and Af f-one rotary systems, canal centrality and transportation were similar at coronal, middle, and apical cross-sections. In addition, canal transportation and centrality were identical in the RaCe and Af f-one rotary files (P<0.05). The two studied rotary systems did not exhibit significant differences in root canal transportation and preservation of root canal centrality in the apical, middle, and coronal thirds.