Multiplanar Reconstruction Research Articles

Reducing crosstalk of a multi-plane holographic display by the time-multiplexing stochastic gradient descent.

Multi-plane reconstruction is essential for realizing a holographic three-dimensional (3D) display. One fundamental issue in conventional multi-plane Gerchberg-Saxton (GS) algorithm is the inter-plane crosstalk, mainly caused by the neglect of other planes' interference in the process of amplitude replacement at each object plane. In this paper, we proposed the time-multiplexing stochastic gradient descent (TM-SGD) optimization algorithm to reduce the multi-plane reconstruction crosstalk. First, the global optimization feature of stochastic gradient descent (SGD) was utilized to reduce the inter-plane crosstalk. However, the crosstalk optimization effect would degrade as the number of object planes increases, due to the imbalance between input and output information. Thus, we further introduced the time-multiplexing strategy into both the iteration and reconstruction process of multi-plane SGD to increase input information. In TM-SGD, multiple sub-holograms are obtained through multi-loop iteration and then sequentially refreshed on spatial light modulator (SLM). The optimization condition between the holograms and the object planes converts from one-to-many to many-to-many, improving the optimization of inter-plane crosstalk. During the persistence of vision, multiple sub-hologram jointly reconstruct the crosstalk-free multi-plane images. Through simulation and experiment, we confirmed that TM-SGD could effectively reduce the inter-plane crosstalk and improve image quality.The proposed TM-SGD-based holographic display has wide applications in tomographic 3D visualization for biology, medical science, and engineering design, which need to reconstruct multiple independent tomographic images without inter-plane crosstalk.

Split-bolus, single-phase contrast enhanced CT: a one-stop shop for invasive fungal sinusitis.

Contrast-enhanced magnetic resonance imaging is considered the imaging modality of choice for invasive fungal sinusitis (IFS); however, it is not feasible to perform emergency CEMRI especially in the setting of COVID-19. The CECT protocol for evaluation of suspected IFS can be modified by using split-bolus, single-phase CT as it provides an optimal soft tissue demonstration of sinonasal disease; extrasinus spread to orbit, and intracranial involvement along with simultaneous opacification of the internal carotid artery and cavernous sinus. The extent of bone erosion can also be well delineated on the multiplanar reconstructions (MPRs) in the bone window. Further a structured reporting format can help provide optimal surgical guidance in cases of IFS.

Can the transection plane be optimized inpancreatic resections?

According to current protocol, the separation of pancreatic head and body is performed at the level of superior mesenteric vein (SMV). Previous data indicate that the resection plane should be modified in portal annular pancreas. We presumed that the optimal line of pancreatic resections could also be different in other cases. Our aim is to simulate pancreatic resections in different planes and find the optimal resection line with the minimum number of cut vessels. 25 abdominal vascular corrosion casts were prepared, the aorta and the portal vein were cannulated. CT scans were taken on the casts, and specific planes were reconstructed simulating different resection lines. The total amount of cross sections of vessels were calculated in the different planes. In our series, the optimal plane is the SMV in 11/25, 2 cm left in 10/25, 1 cm left in 4/25, 1 cm right in 1/25 and 2 cm right in none of our cases. The group of left sided extension contain more than half of the cases. With left sided resections, the cut surface of the vessels may be lowered to even 29% compared to the SMV plane. Our study revealed that pancreatic resections should be extended to the left side of the SMV in more than half of our cases. Therefore, the resection plane should be determined by preoperative imaging methods. Using DICOM viewer with multiplanar reconstruction, the resection planes can be simulated in clinical practice, which would reduce the risk of postoperative bleeding.

Measuring direct and indirect tendon parameters to characterize the proximal tendinous complex of the rectus femoris in football and futsal players.

Objective: To present unprecedented radiological parameters that characterize the angle between the direct and indirect tendons of the proximal rectus femoris (RF) and its inclinations and to evaluate the population variability according to demographic variables. Materials and methods: From September 2019 to July 2021, using MRI multiplanar reconstructions of the proximal thigh/hip, two blinded radiologists measured the direct and indirect tendon angle and the inclination of each tendon in different planes. The intra- and inter-observer agreements were assessed with Bland-Altman analysis and intraclass correlation coefficient (ICC). The correlations between radiological parameters and demographic variables were evaluated using linear regression, Student's t-test, and analysis of variance. Results: We performed 112 thigh/hip MRI scans on 91 football players of different age, gender, and disciplines (football and futsal). For observer 1 (the reference), the mean direct and indirect tendon angle was 56.74° ± 9.37, the mean indirect tendon slope was -7.90° ± 7.49, and the mean direct tendon slope was 22.16° ± 5.88. The three measurements showed inter- and intra-observer agreement (mean differences ∼0). No correlation was observed between age and the parameters. Likewise, no statistically significant differences were found for gender, dominant limb, examined limb, and sport. Conclusion: There is an inter- and intra-observer agreement in the measurements of the direct and indirect tendon angle and the inclination of each tendon. There is population variability in the proximal tendinous complex unrelated to demographic factors. These results allow further detection of morphological patterns that represent a risk factor for lesions in the RF in professional football and futsal players and other sports.

Our Experience in Tracking the Tract: Normal Biliary Anatomy and Variants on Magnetic Resonance Cholangiopancreatography in Living Donor Liver Transplantation.

Objective Biliary anatomy is of paramount importance for hepatobiliary pancreatic surgeons for operative planning. Preoperative assessment with magnetic resonance cholangiopancreatography (MRCP) to evaluate the biliary anatomy plays a vital role, especially for prospective liver donors in living donor liver transplantation (LDLT). Our objective was to evaluate the diagnostic accuracy of MRCP in assessing the anatomical variations of the biliary system and the frequency of biliary variation in the donors of LDLT. Materials and Methods Sixty-five donors of living donor liver transplantation in the age range of 20 to 51 years were studied retrospectively to evaluate the anatomical variations of the biliary tree. As a part of the pre-transplantation donor workup, MRI with MRCP was performed in a 1.5T machine for all these candidates. MRCP source data sets were processed with maximum intensity projections, surface shading, and multi-planar reconstructions. Images were reviewed by two radiologists, and the classification system of Huang et al. was utilized to evaluate the biliary anatomy. The results were compared with the intraoperative cholangiogram, considered the gold standard. Results We identified standard biliary anatomy in 34 candidates (52.3%), and variant biliary anatomy was observed in 31 candidates (47.7%) on MRCP. An intraoperative cholangiogram showed standard anatomy in 36 candidates (55.4%) and biliary variation in 29 candidates (44.6%). Our study showed a sensitivity of 100% and a specificity of 94.5% for identifying biliary variant anatomy on MRCP in comparison with the gold standard intraoperative cholangiogram. The accuracy of MRCP in detecting the variant biliary anatomy in our study was 96.9%. The most common biliary variation was the right posterior sectoral duct draining into the left hepatic duct, Huang type A3. Conclusion The frequency of biliary variations is high in potential liver donors. MRCP is sensitive and highly accurate in identifying the biliary variations of surgical significance.

Multiplane Image Restoration Using Multivariate Curve Resolution: An Alternative Approach to Deconvolution in Conventional Brightfield Microscopy

Three-dimensional reconstruction in brightfield microscopy is challenging since a 2D image includes from in-focus and out-of-focus light which removes the details of the specimen’s structures. To overcome this problem, many techniques exist, but these generally require an appropriate model of Point Spread Function (PSF). Here, we propose a new images restoration method based on the application of Multivariate Curve Resolution (MCR) algorithms to a stack of brightfield microscopy images to achieve 3D reconstruction without the need for PSF. The method is based on a statistical reconstruction approach using a self-modelling mixture analysis. The MCR-ALS (ALS for Alternating Least Square) algorithm under non-negativity constraints, Wiener, Richardson–Lucy, and blind deconvolution algorithms were applied to silica microbeads and red blood cells images. The MCR analysis produces restored images that show informative structures which are not noticeable in the initial images, and this demonstrates its capability for the multiplane reconstruction of the amplitude of 3D objects. In comparison with 3D deconvolution methods based on a set of No Reference Images Quality Metrics (NR-IQMs) that are Standard Deviation, ENTROPY Average Gradient, and Auto Correlation, our method presents better values of these metrics, showing that it can be used as an alternative to 3D deconvolution methods.

Prevalence and predictors of combined >50% iliocaval venous obstruction and superficial venous reflux in chronic venous insufficiency patients with healed or active venous leg ulcer

ObjectiveThe aim of the present study was to investigate the prevalence and predictors of combined >50% iliocaval venous obstruction (ICVO) and superficial venous reflux (SVR) in patients with chronic venous insufficiency (CVI) with a healed (C5) or an active (C6) venous leg ulcer (VLU). MethodsWe conducted a retrospective review of prospectively collected data from patients with CVI with CEAP (Clinical, Etiology, Anatomy, Pathophysiology) class C5 (healed ulcer) or C6 (active ulcer) with SVR who had been treated at our institution from February 2017 to January 2018. The demographic, clinical, and surgical data and duplex ultrasound and computed tomography venography findings were collected. We used OsiriX MD, version 2.9, software (Pixmeo SARL, Bernex, Switzerland) to measure the vein diameter via multiplanar reconstruction. The prevalence of combined >50% ICVO and SVR was evaluated, and univariate and multivariate analyses were performed to identify the independent predictors of >50% ICVO in patients with CVI and SVR. ResultsA total of 79 limbs from 67 patients were enrolled. The mean age was 59.82 ± 12.86 years, the mean body mass index was 28.68 ± 6.41 kg/m2, and 41.8% were men. The prevalence of >50% ICVO in the patients with SVR was 31.6%. Univariate analysis showed a history of deep vein thrombosis (DVT) in the affected leg (P = .001), a VLU in the left leg (P = .033), a history of a recurrent VLU (P = .038), and reversed flow in the superficial epigastric vein (P = .004) were significantly associated with >50% ICVO in patients with CVI and SVR. Multivariate analysis revealed a history of DVT in the affected leg (adjusted odds ratio [aOR], 8.31; 95% confidence interval [CI], 2.29-30.19; P = .001), a VLU in the left leg (aOR, 3.95; 95% CI, 1.18-13.19; P = .026), and a history of a recurrent VLU (aOR, 3.08; 95% CI, 1.02-9.32; P = .047) to be independently associated with combined >50% ICVO and SVR in patients with CVI. ConclusionsThe prevalence of combined >50% ICVO and SVR in patients with CVI and CEAP C5 or C6 was 31.6%. The independent predictors of combined >50% ICVO and SVR in those with CVI were a history of DVT in the affected leg, a VLU in the left leg, and recurrent VLUs.

Imaging findings of hepatocellular carcinoma with portal vein tumor thrombosis secondary to hepatic portal vein collateral circulation: a cross-sectional study.

Hepatic portal vein collateral circulation plays an important role in maintaining the perfusion of hepatic portal vein. However, at present, there is little research on collateral circulation of hepatic portal vein. Our study aims to analysis the imaging types and clinical value of hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT) invading and completely blocking different branches of portal vein, secondary to hepatic portal vein collateral circulation. This study retrospectively analyzed Hepatocellular carcinoma (HCC) with PVTT diagnosed with enhanced CT examination of the upper abdomen in our hospital from May 2020 to October 2021.The inclusion criteria for patients were the following: (I) ultimately diagnosed with HCC, (II) accompanied by complete obstruction of the main portal vein or left/right branches, and (III) with collateral circulation of the hepatic portal vein established. All images were postprocessed by multiplanar reconstruction (MPR), maximum intensity projection (MIP), and other reconstruction techniques to obtain images of the abnormal portal vein system and the collateral vessels running toward the hepatic portal veins. Three physicians jointly judged the imaging anatomical classification of each collateral vessel. The qualitative variables were compared by chi-squared test. A total of 125 hepatic portal vein collateral vessels were observed in MPR and MIP reconstruction images of 71 patients with portal vein cancer thrombosis with established hepatic portal vein collateral circulation. Common hepatic collateral branches in patients with PVTT mainly include the biliary collateral branch, gastric collateral branch, mesenteric collateral branch, accessory portal vein system and the splenic branch. The incidence rate was respectively 77.5%, 36.6%, 32.4%, 28.2%, 1.41%. The correct understanding of the imaging anatomical classification of the collateral vessels of the hepatic portal vein can provide clinicians with more information for diagnosis and treatment planning.

Anatomical and clinical aspects and outcomes of bilateral cochlear implantation in cochlear hypoplasia type IV - a case report

Cochlear hypoplasia is a congenital inner ear malformation (IEM) characterized by a reduced external cochlear dimension, usually accompanied by an abnormal internal architecture. Type IV cochlear hypoplasia is a cochlea with hypoplastic middle and apical turns. It may occur along with dislocation of the facial nerve, associated with semicircular abnormalities, less clearly marked promontory, or stapedial fixation. Such patients can present a broad spectrum of audiological test results, from sensorineural or mixed mild or profound hearing loss. The above anatomical changes may be responsible for intraoperative difficulties during cochlear implantation. In the studied case, a 6-month-old patient was diagnosed with an inner ear malformation - cochlear hypoplasia type IV on both sides. Computed tomography with multiplanar and 3D reconstruction was performed to analyze the middle and inner ear anatomy in detail. Both types of imaging reconstruction helped decide which cochlear implant electrode to choose. Perimodiolar-positioned cochlear implant electrode was found to be the most suitable choice. The patient underwent sequential bilateral cochlear implantation with expected incomplete electrode array insertion on both sides. First repeatable auditory responses were observed two months after the second implant activation. Good parental cooperation with therapists and adequately defined developmental goals in the presented patient allowed the multidisciplinary team to take advantage of the child's intellectual abilities and choose the suitable communication method; however, the patient's auditory responses were obtained slowly. The final auditory results cannot be predicted in inner ear malformations due to abnormal anatomical structure and, thus, heterogeneous innervation within the deformed cochlea. The programming of the sound processor must be individual in each case, based on the child's behavior observation and, if possible, objective test results. Patients with cochlear malformations usually require higher stimulation intensities to obtain sound sensations than patients with a typical cochlear structure.

Transesophageal Echocardiographic Screening for Structural Heart Interventions.

Percutaneous structural interventions have provided patients with an effective therapeutic option, and its growth has been aided by echocardiography. We describe the vital role that transesophageal echocardiography (TEE) plays in screening patients prior to their procedure. A multimodality imaging approach is employed by the valve team, but TEE plays a unique role in diagnosis and planning. Utilization of all TEE views and features such as biplane, 3D imaging, and multiplanar reconstruction ensures accurate assessment of the structural lesion of interest. The role of TEE remains essential in the planning of structural interventions, and these studies should be performed in a systematic and comprehensive manner.

Elastomer-Embedded Multiplexed Optical Fiber Sensor System for Multiplane Shape Reconstruction

This paper presents the development and application of a multiplexed intensity variation-based sensor system for multiplane shape reconstruction. The sensor is based on a polymer optical fiber (POF) with sequential lateral sections coupled with a flexible light-emitting diode (LED) belt. The optical source modulation enables the development of 30 independent sensors using one photodetector, where the sensor system is embedded in polydimethylsiloxane (PDMS) resin in two configurations. Configuration 1 is a continuous PDMS layer applied in the interface between the flexible LED belt and the POF, whereas Configuration 2 comprises a 20 mm length PDMS layer only on each lateral section and LED region. The finite element method (FEM) is employed for the strain distribution evaluation in different conditions, including the strain distribution on the sensor system subjected to momentums in roll, pitch and yaw conditions. The experimental results of pressure application at 30 regions for each configuration indicated a higher sensitivity of Configuration 1 (83.58 a.u./kPa) when compared with Configuration 2 (40.06 a.u./kPa). However, Configuration 2 presented the smallest cross-sensitivity between sequential sensors (0.94 a.u./kPa against 45.5 a.u./kPa of Configuration 1). Then, the possibility of real-time loading condition monitoring and shape reconstruction is evaluated using Configuration 1 subjected to momentums in roll, pitch and yaw, as well as mechanical waves applied on the sensor structure. The strain distribution on the sensor presented the same pattern as the one obtained in the simulations, and the real-time response of each sensor was obtained for each case. In addition, the possibility of real-time loading condition estimation is analyzed using the k-means algorithm (an unsupervised machine learning approach) for the clusterization of data regarding the loading condition. The comparison between the predicted results and the real ones shows a 90.55% success rate. Thus, the proposed sensor device is a feasible alternative for integrated sensing in movement analysis, structural health monitoring submitted to dynamic loading and robotics for the assessment of the robot structure.

Length of the healthy and pathological small intestine in patients with Crohn's disease: calculations using computed tomography and magnetic resonance enterography.

Many patients with Crohn's disease (CD) require surgical intervention during their lifetime. A correct preoperative assessment of the intestinal length is necessary to predict and quickly treat postoperative nutritional disorders. The aim of this paper is to explain the method used in our hospital to measure intestinal length in patients with CD and its usefulness for making the correct therapeutic decision. Vessel analysis software is used to measure small bowel length through computed tomography enterography (CTE) or magnetic resonance enterography (MRE). The method permits two-dimensional and three-dimensional curved multiplanar reconstructions and allows each loop to be stretched using a point-by-point identification of the intestinal lumen. Subsequently, the software allows the creation of a virtual image, on which the intestinal length is measured linearly. This methodology was tested on three patients; patients 1 and 3 were examined using CTE, and patient 2 was examined using MRE. The outcomes were discussed at a multidisciplinary team meeting (MDT). As a result, surgical ileocolic resection was recommended for patient 1 and medical therapy for patients 2 and 3. Intestinal length measurements have proved vital during MDTs for making appropriate therapeutic decisions.

Spring Plates as a Valid Additional Fixation in Comminuted Posterior Wall Acetabular Fractures: A Retrospective Multicenter Study.

The posterior wall fracture is the most frequent pattern of acetabular fractures. Many techniques of fixation have been described in the literature and involve plates, screws, or a combination of both. This study aims to investigate the clinical and radiological outcomes of spring plates in the treatment of comminuted posterior wall acetabular fractures. (2) Methods: A retrospective multicenter (four level I trauma centers) observational study was performed. Patients with a comminuted posterior wall acetabular fracture treated with a spring plate (DePuy Synthes, West Chester, PA) were included. Diagnosis was made according to the Judet and Letournel classification. Diagnosis was confirmed with plain radiographs in an antero-posterior view and Judet views, iliac and obturator oblique views, and thin-slice CT with multiplanar reconstructions. (3) Results: Forty-six patients (34 males and 12 females) with a mean age of 51.7 years (range 19-73) were included. The most common mechanism of injury was motor vehicle accident (34 cases). In all cases, spring plates were placed under an overlapping reconstruction plate. The mean follow-up was 33.4 months (range 24-48). The mean period without weight-bearing was 4.9 weeks (range 4-7), and full weight-bearing was allowed at an average of 8.2 weeks (range 7-11) after surgery. (4) Conclusions: According to the present data, spring plates can be considered a viable additional fixation of the posterior wall acetabular fractures.

C2 pedicle screw placement on 3D-printed models for the performance assessment of CTA-based screw preclusion

Background3-D printing technology has a large spectrum of applications in upper cervical spinal surgery, but none have evaluated the radiological analysis of the feasibility of C2 pedicle screw placement. Thus, this study aimed to perform 3.5-mm-diameter C2 pedicle screw placement on models for performance assessment of CTA-based preoperative screw preclusion.MethodsWe enrolled 152 patients who underwent CTA of the cervical spine between April 2020 and December 2020. Transverse pediculoisthmic width (TPW), oblique pediculoisthmic width (OPW), minimum pediculoisthmic diameter (MPD), internal height, and isthmus height were measured preoperatively. Subsequently, 1:1 3D-printed bone models were created, and a 3.5-mm-diameter C2 pedicle screw was placed on the models. All 3D-printed models underwent postoperative CT multiplanar reconstruction to evaluate the screw trajectory for the performance assessment of CTA-based preoperative screw preclusion.ResultsThe ROC curves of the MPD, TPW, OPW, Internal height and Isthmus height showed that the optimal cutoff values for each of the five groups were measured values of 4.78, 4.44, 4.37, 4.22 and 5.59 mm, respectively. The AUC, sensitivity, and specificity of MPD were 0.992, 95.1% and 100%, respectively. The MPD had higher metrics than the TPW (AUC, 0.949; sensitivity, 87.9%), internal height (AUC, 0.885; sensitivity, 80.8%; specificity, 84.6%), and isthmus height (AUC, 0.941; sensitivity, 87.2%). We found no evidence of a difference between MPD and OPW in terms of the AUC and sensitivity (0.93 and 95.5%, respectively).ConclusionsC2 pedicle screw placement on 3D-printed models is useful for performance assessment of CTA-based preoperative screw preclusion. MPD measurement with CTA multiplanar reconstruction showed the best performance for judging acceptable or unacceptable screws. However, the definition of HRVA could be modified by a 4.2 mm-internal height or by measuring only the isthmus height for judging the preclusion of C2 pedicle screw placement.

Cone-beam computed tomographic reconstructions in the evaluation of maxillary impacted canines.

Prior to cone-beam computed tomography (CBCT), orthodontic competence included radiological interpretation. Nevertheless, maxillary impacted canines (MICs), because of their position and adjacent complex anatomy, have been challenging to interpret, particularly with regard to root resorption. Although CBCT cross-sectional reconstructions of MICs yielded clearer insights into its diagnosis and treatment planning, the value of simultaneously using 2 different cross-sectional or multiplanar reconstructions of the CBCT datasets - orthogonal and curved/panoramic multiplanar reconstructions - has hitherto not been considered. Both orthogonal and curved/panoramic multiplanar reconstruction series of 5 screenshots were each reconstructed from the 5 cm × 5 cm CBCT datasets of 15 separate MICs. Fifteen credentialled and experienced orthodontist volunteers reviewed 2 separate PowerPoints of 15 randomized series each, 1 week apart. Their review considered 6 factors that could affect treatment: the position and level of the MIC, the presence or absence of root resorption, ankylosis, cysts, and dilaceration. All 15 orthodontists were statistically similar regarding overall years of experience and of CBCT use. Although either reconstruction alone allowed the orthodontists to determine whether ankylosis and, to a lesser extent, most of the other features were present or absent in the MIC, reviewing both reconstructions together was necessary to determine whether root resorption was present or absent in the adjacent tooth. Reviewing both orthogonal and curved/panoramic multiplanar reconstructions was necessary to evaluate the presence or absence of root resorption in the teeth adjacent to MICs and that of many other features.

Cone-beam computed tomographic evaluation of the root canal anatomy of the lower premolars and molars in a Brazilian sub-population.

This study evaluated anatomical variations in the root canals of the lower premolars and molars in a Brazilian sub-population using cone-beam computed tomography (CBCT). In total, 121 CBCT images of patients were selected from a database. All images contained lower first and second premolars and molars on both sides of the arch, fully developed roots, and no treatment, resorption, or calcifications. In each image, the root canals of the lower premolars and molars were evaluated according to the Vertucci classification in On-Demand 3D software in the multiplanar reconstruction with dynamic navigation. Twenty-five percent of the images were re-assessed to analyze intraobserver confidence with the kappa test. Data were statistically evaluated with linear regression to evaluate the correlations of anatomic variations with age and sex, and the Wilcoxon test to analyze the laterality of variations, with a significance level of 5%. The intraobserver agreement (0.94) was excellent. In general, the root canals of lower premolars and molars showed a higher prevalence of type I than other Vertucci classification types, followed by type V in premolars and type II in molars. When the molar roots were evaluated separately, type II was more frequent in mesial roots and type I in distal roots. Although age showed no correlations with the results, sex and laterality showed correlations with tooth 45 and the lower second premolars, respectively. The lower premolars and molars of a Brazilian sub-population showed a wide range of root canal anatomic variations.

An Updated Review of Magnetic Resonance Neurography for Plexus Imaging.

Magnetic resonance neurography (MRN) is increasingly used to visualize peripheral nerves in vivo. However, the implementation and interpretation of MRN in the brachial and lumbosacral plexi are challenging because of the anatomical complexity and technical limitations. The purpose of this article was to review the clinical context of MRN, describe advanced magnetic resonance (MR) techniques for plexus imaging, and list the general categories of utility of MRN with pertinent imaging examples. The selection and optimization of MR sequences are centered on the homogeneous suppression of fat and blood vessels while enhancing the visibility of the plexus and its branches. Standard 2D fast spin-echo sequences are essential to assess morphology and signal intensity of nerves. Moreover, nerve-selective 3D isotropic images allow improved visualization of nerves and multiplanar reconstruction along their course. Diffusion-weighted and diffusion-tensor images offer microscopic and functional insights into peripheral nerves. The interpretation of MRN in the brachial and lumbosacral plexi should be based on a thorough understanding of their anatomy and pathophysiology. Anatomical landmarks assist in identifying brachial and lumbosacral plexus components of interest. Thus, understanding the varying patterns of nerve abnormalities facilitates the interpretation of aberrant findings.

Axial Rotation of the Talus in Progressive Collapsing Foot Deformity: A Weightbearing Computed Tomography Analysis

Category: Hindfoot; Midfoot/Forefoot Introduction/ Purpose: Progressive collapsing foot deformity (PCFD) is recognized as a three-dimensional deformity centered around the talus. Although sagittal plane talar sagging or coronal plane valgus talar tilt have been well described, axial plane alignment referencing the talus, calcaneus and second metatarsal to the ankle has not been studied in PCFD patients. The purpose of this study was to examine the axial plane alignment of PCFD versus controls using weightbearing computed tomography (WBCT) and to determine if talar rotation in the axial plane is associated with increased abduction deformity. We hypothesized that the talus would exhibit greater internal rotation in PCFD patients than in control patients, and that this rotation would increase with worsening abduction deformity. Methods: Multiplanar reconstructed (MPR) WBCT scans of 79 patients with PCFD were analyzed. Patients were divided into two groups according to their preoperative talonavicular coverage angle (TNC): moderate abduction (TNC 20-40, n=57) and severe abduction (TNC >40, n=22). 39 WBCT scans from healthy patients without PCFD or hindfoot deformity were included as controls. Using the MPR WBCT images, the axis of talus (TM [transmalleolar]-Tal), calcaneus (TM-Calc), and 2nd metatarsal (TM-2MT) were measured in reference to the transmalleolar axis (Figure 1). Smaller angles represented internal rotation relative to the TM axis. The difference between TM-Tal and TM-Calc was calculated to assess talocalcaneal subluxation. The prevalence of medial tibiotalar joint space narrowing, which was assessed with medial to dorsal tibiotalar joint space ratio (M/D ratio < 0.5 was defined as ‘narrowing’), and medial ankle spurs were also evaluated. Results: TM-Tal was significantly smaller in PCFD patients compared to controls (Figure 2). This difference was accentuated in PCFD with severe abduction, who saw significantly smaller TM-Tal than the moderate abduction group. TM-Calc did not differ between groups, indicating similar axial calcaneal orientation. The TM-2MT revealed a significant difference between groups, reflecting foot abduction in PCFD. Diff Tal-Calc values were greater in PCFD patients, indicating that PCFD patients have more talocalcaneal subluxation in the axial plane. The severe abduction group had a higher Diff Tal-Calc value than the moderate abduction group. PCFD patients had a significantly higher prevalence of medial ankle joint space narrowing and medial spur formation than controls; however, there were no significant differences between the severe and moderate abduction groups. Conclusion: This study found that internal rotation of the talus is a key component of PCFD and is accentuated in more severe abduction deformities. These findings suggest that talar malrotation in the axial plane should be considered an underlying feature of abduction deformity and that this deformity should be corrected at the time of reconstructive surgery, especially in cases of severe abduction deformity. In addition, these findings support the observations of medial joint narrowing and medial spur formation in PCFD patients. Further research is warranted to identify optimal strategies for correction of talar rotation and how to reproducibly assess this intraoperatively.

Creation of 3D Stereo and MPR Color Anatomical Charts in the Hepatic Segments

We used the Voronoi diagram of a computed tomography (CT) application (i.e., CT liver volume measurement) to depict the liver area, and we obtained depictions of the hepatic segments as a three-dimensional (3D) image based on clinical data; this information can be used for the patient's education and for surgical planning. The hepatic segments use the inter-relationships among the eight subsegments illustrated by Couinaud, those indicated by the portal veins and those provided by hepatic veins. The liver has dual portal and arterial innervation, with the thick portal vein intertwined with thin arteries similar to the intertwining of ivy plants. Couinaud divided the liver into eight segments (S1 to S8) based on portal vein casts. The Voronoi diagram estimates the dominant region of the portal vein, divides the liver into segments, and produces 3D images and multiplanar reconstruction (MPR) images in color. To support understanding of Couinaud's eight hepatic segments (which are explained only in the illustration of the frontal view of the liver), using 3D images created by the Voronoi diagram, we created 3D stereo color anatomical charts of the liver that Couinaud's eight hepatic segments can be confirmed from multiple directions. In addition, we created the MPR color anatomical charts of the liver (S1 to S8) that can be confirmed by color from three directions: axial images, coronal images, and sagittal images in the same way. We converted the data of this anatomical chart into an electronic file that provides a tool that can be easily used in radiological examinations, and we were able to make improvements based on requests from users.

Congenital lung malformations: can we avoid computed tomography? A five-year study.

Congenital lung malformations (CLMs) consist of a variety of pulmonary development disorders. In the CLM approach, computed tomography (CT) is considered the gold standard imaging technique due to the high-resolution for the lung parenchyma evaluation, the study of the vascular system after contrast injection, and the multiplanar reconstructions. In the paediatric population CT is considered too invasive due to ionizing radiation and the use of contrast agent. Therefore, the indications for the use of magnetic resonance imaging (MRI) are increasing. The aim of our study is to compare retrospectively MRI and CT in the evaluation of CLMs, to reduce or avoid the use of contrast-enhanced CT in the paediatric population. We retrospectively evaluated 22 paediatric patients with prenatal diagnosis of CLMs. All the patients underwent postnatal MRI in the first 2 weeks of life (except for a patient) and pre-surgery contrast-enhanced CT. A total of 7 blinded radiologists divided into 3 different groups independently reviewed each MRI and CT examination. Sensitivity and specificity of radiologists with different years of experience on the field, as well as of MRI findings regarding every pathology, were evaluated using a ROC curve. The interobserver agreement regarding the MRI findings was also measured. Analysing the ROC curves, we observed that MRI provided a satisfactory accuracy for diagnosing most congenital pulmonary diseases. Our study showed that MRI without contrast agent allows us to reach a CLM diagnosis in good agreement with contrast-enhanced CT, which is considered the gold standard imaging technique.