Craniocaudal Distance Research Articles

Effect of bar jump height on kinetics and kinematics of take-off in agility dogs.

Sport-related injuries have been reported to occur in around one-third of agility dogs. Higher bar height in competitions has been shown to increase odds of an injury. This study evaluated the effect of bar height on the kinetics and kinematics at take-off to a bar jump. Forces from fore- and hindlimb pairs were measured with force plates. A three-dimensional motion capture system was used to measure sagittal joint kinematics of the shoulder, elbow, carpus, hip, stifle, and tarsal joints, as well as limb coordination, trunk horizontal velocity, take-off distance, and take-off angle. Data were collected for 17 Border Collies at three different bar heights: 80%, 100%, and 120% of wither height. A linear mixed model was used for statistical analysis. At higher bar height, decelerative impulses were greater and accelerative impulses decreased along with greater vertical impulses from forelimb and hindlimb pairs (p<0.001). Post-hoc analyses revealed differences between all three bar heights (p<0.01), except for forelimb decelerative impulse, which did not differ between 80% and 100% heights. Sagittal range of motion was greater, through increased peak flexion or extension, at 120% bar height than at lower bar heights (p<0.05) in almost all measured limb joints. The only exceptions were leading forelimb shoulder and elbow joints and leading hindlimb hip joint. With increasing bar height, the horizontal velocity of trunk decreased (p<0.001), and take-off angle became steeper (p<0.001), with all bar heights differing from each other (p<0.01). Temporal synchronicity between trailing and leading limbs increased and craniocaudal distance decreased in forelimbs (p<0.05) and hindlimbs (p<0.01) as bar height increased. Increased vertical and decelerative impulses, as well as the greater peak flexion and extension angles of joints, may indicate greater load on the tissues at higher bar heights, which could explain the increased odds of injury at higher bar heights in agility dogs.

Endoscopic approaches to the posterior wall of the third ventricle: An anatomical comparison

IntroductionSurgery of lesions in the posterior wall of the third ventricle requires great expertise due to its deep location and important surrounding structures. This region has been traditionally reached through a supracerebellar infratentorial approach, but new options have emerged, especially with the development of neuroendoscopy. MethodsOne formalin-fixed cadaver human head was dissected. Five different endoscopic approaches were performed: interhemispheric transcallosal transchoroidal, frontal transforaminal transchoroidal, supraorbital subfrontal translamina terminalis, expanded endonasal, and supracerebellar infratentorial. An anatomical description of the different approaches was conducted and quantitative measurements (craniocaudal and latero-lateral distances) were taken using the StealthStation ® workstation after performing a CT scan of the specimen. ResultsThe interhemispheric transcallosal transchoroidal, frontal transforaminal transchoroidal, and supraorbital subfrontal translamina terminalis approaches provided great view of all the structures of the posterior wall of the third ventricle. Maximum craniocaudal distance was obtained through the supraorbital subfrontal translamina terminalis approach (10.6 mm), with great difference from the expanded endonasal approach (5.2 mm). The widest latero-lateral distance from inside the third ventricle was achieved through the interhemispheric transcallosal transchoroidal approach (4.6 mm), similar to the expanded endonasal (4.1 mm), and differing from the supraorbital subfrontal translamina terminalis (2.4 mm). ConclusionsThe endoscopic approaches provided an adequate alternative to more traditional microsurgical approaches to the posterior wall of the third ventricle, with a great view of all its structures. The selection of the approach must be taken under consideration in each case.

Respiratory Displacement of the Right Adrenal Vein: Comparison of Inspiratory and Expiratory Computed Tomography With Catheter Venography.

The aim of the study is to reveal the respiratory displacement of the right adrenal vein (RAV) to predict the exact location of the RAV during adrenal venous sampling (AVS). Computed tomography (CT) scans obtained 45 seconds (breath-hold at inhalation) and 70 seconds (breath-hold at exhalation) after contrast material injection were compared to venograms of the RAV of patients with primary aldosteronism who underwent AVS between January 2016 and December 2020. The craniocaudal distance between the center of the Th11/12 disc and the RAV orifice was measured; the craniocaudal location of the RAV orifice was also specified relative to vertebral bodies and intervertebral discs on inspiratory phase CT (In-CT), expiratory phase CT (Ex-CT), and catheter venography. The transverse and vertical angles of the RAV and the position of the RAV orifice on the inferior vena cava (IVC) circumference were measured on In-CT and Ex-CT. In total, 51 patients (30 males, 21 females; mean age, 54.9 ± 11.1 years) were included. Craniocaudal distances between the center of the Th11/12 disc and RAV orifice were significantly different among the following 3 acquisitions: catheter venography versus In-CT (15.2 ± 8.4 mm); venography versus Ex-CT (5.6 ± 4.1 mm); and In-CT versus Ex-CT (19.6 ± 8.0 mm) (all, P < 0.001). The craniocaudal location of the RAV orifice on venography was significantly closer to that on Ex-CT than on In-CT ( P < 0.001); measurements using venograms compared with In-CT and Ex-CT scans were within 1 level difference in 18 (35.3%) and 47 (92.2%) patients, respectively ( P < 0.001). The vertical angle of the RAV was significantly more likely to be smaller on In-CT than on Ex-CT ( P < 0.001). RAV locations and angles change with respiratory motion. It is crucial to consider the respiratory phase of CT because it can enable a more accurate prediction of the location of the RAV during AVS.

Flexible in-cavity MRI receiving coil for ultra-high-resolution imaging of the pituitary gland.

The objective of this study was the preclinical design and construction of a flexible intrasphenoid coil aiming for submillimeter resolution of the human pituitary gland. Sphenoid sinus measurements determined coil design constraints for use in > 95% of adult patients. Temperature safety parameters were tested. The 2-cm-diameter coil prototype was positioned in the sphenoid sinus of cadaveric human heads utilizing the transnasal endoscopic approach that is used clinically. Signal-to-noise ratio (SNR) was estimated for the transnasal coil prototype compared with a standard clinical head coil. One cadaveric pituitary gland was explanted and histologically examined for correlation to the imaging findings. With the coil positioned directly atop the sella turcica at a 0° angle of the B0 static field, the craniocaudal distance (21.2 ± 0.8 mm) was the limiting constraint. Phantom experiments showed no detectable change in temperature at two sites over 15 minutes. The flexible coil was placed transnasally in cadaveric specimens using an endoscopic approach. The image quality was subjectively superior at higher spatial resolutions relative to that with the commercial 20-channel head coil. An average 17-fold increase in the SNR was achieved within the pituitary gland. Subtle findings visualized only with the transnasal coil had potential pathological correlation with immunohistochemical findings. A transnasal radiofrequency coil feasibly provides a 17-fold boost in the SNR at 3 T. The ability to safely improve the quality of pituitary imaging may be helpful in the identification and subsequent resection of small functional pituitary lesions.

The Displacement Patterns of Petrous Internal Carotid Artery and Its Morphometric Relations with Vidian Canal in Petroclival Chondrosarcomas Relevant to Extended Endoscopic Endonasal Approaches: A Radiological Study

PurposeExtended endoscopic endonasal approaches (EEAs) to petroclival chondrosarcomas (PCs) require a thorough understanding of skullbase anatomy, especially the anatomy of petrous ICA (pICA), as ICA injury is the most dreaded complication of extended EEAs. We conducted this study to determine the displacement patterns of pICA in patients with PCs. MethodsCECT & angiography images of patients with PCs were analyzed for following parameters -antero-posterior (AP), cranio-caudal (CC), medio-lateral (ML) & direct distances between anterior genu of pICA (AGpICA) and posterior end of vidian canal (pVC). pICA encasement/ narrowing by tumor was noted on MRI images. ResultsWe studied 11 patients with histopathologically proven PCs. pICA encasement/narrowing & pVC destruction were observed in one patient each. The mean AP & CC distances on tumor side/normal side were 7.7±1.9/6.4±1.0mm & 4.5±1.5/3.4±0.9mm, respectively. The overall displacement was posterior & superior. ML displacement was seen in 4 patients (lateral in 3 & medial in 1). In rest, AGpICA was centered on pVC. The mean direct distance was 9.4±2.5 mm. In 3 patients with displacement seen in all three axes, direct distance was measured by the “cuboid method”. Overall, posterior-superior-lateral, posterior-superior & anterior-inferior were the common displacement patterns of AGpICA relative to pVC. ConclusionsThe displacement patterns of AGpICA in PCs are variable. An individualized approach with meticulous analysis of preoperative imaging can help in determining the relation between AGpICA & pVC. This detailed morphometric information can facilitate better orientation to altered anatomy, which can be helpful in preventing pICA injury during extended EEAs.

The distance between the falx cerebri and the corpus callosum in patients with bilateral subdural hematomas: A potential measure of disease severity

BackgroundWe aimed to assess the usefulness of the falx cerebri and the corpus callosum measurements as imaging markers of the evaluation of patients with bilateral subdural hematomas. MethodsThe anterior-posterior and craniocaudal distances between the falx cerebri (FC) and the corpus callosum (CC) were retrospectively measured in 88 head CT scans from 2018 to 2022 from patients with bilateral subdural hematomas and associated with quantitative data and clinical outcomes. Statistical analysis was performed using multivariate regression and receiver operating characteristic curves. ResultsOf the 88 patients included, 77.3% were male and the median age of 76.0 years (interquartile range 14.0). The mean craniocaudal and anterior-posterior FC-CC distances were 27.6 ± 6.2 mm and 25.1 ± 6.9 mm, respectively, and showed a positive correlation with hematoma thickness and volume. Both anterior-posterior and craniocaudal FC-CC distances exhibited moderate to good inter-rater reliability. After adjusting for confounders, the craniocaudal FC-CC distance was associated with an increased risk of altered consciousness at admission (OR=1.013; 95% CI 1.001–1.024; p = 0.031), downward displacement of the third ventricle (OR=1.019; 95% CI 1.001–1.038; p = 0.035), and a reduced time to surgery (β = 0.057; 95% CI 0.007–0.107; p = 0.027). ConclusionThis study emphasizes that increased FC-CC distances in patients with bilateral subdural hematomas may aid clinical decision-making and are associated with larger hematoma volumes, evidence of descending transtentorial herniation on imaging, and a heightened risk of altered consciousness at admission.

Can Supine Breast Magnetic Resonance Imaging After a Dynamic Contrast-Enhanced Breast Magnetic Resonance Imaging Provide Information for Supine Procedures?

A retrospective analysis was conducted on 75 lesions in 50 patients with pathologically proven breast cancer who underwent MRI in prone and supine positions between December 2019 and December 2020. The transverse, anteroposterior, and craniocaudal dimensions (in millimeters) of the tumor in the x -, y -, and z -axes were measured. Distances from the center of the tumor to the chest wall and the adjacent skin were measured on transverse and reformatted sagittal images. In cases where multifocal lesions were present, the transverse, anteroposterior, and craniocaudal distances between the tumor centers in the x -, y -, and z -axes were measured. Differences between measurements in supine and prone MRI were evaluated with the Mann-Whitney U and the Wilcoxon tests. P values of less than 0.05 were considered to indicate a statistically significant difference. The analysis revealed 31 MRIs with 1 and 20 with multifocal lesions. The x -axis dimension of the lesions in prone and supine positions did not significantly differ ( P = 0.198) between the 2 positions. A significant difference in the y - and z -axes dimensions was observed between the prone and supine position ( P = 0.00 for both). The distance from the tumor to the chest wall and the adjacent skin showed significant difference ( P = 0.00 for both). For multifocal lesions, the distance between the lesions showed a significant difference on the y -axis ( P = 0.00). This study showed a significant difference in the tumor size, location, and tumor-to-tumor distances due to change of patient position, from the standard prone MRI to the supine position in the operating room, resulting in distortion, spatial repositioning, and convergence of the lesions. Supine MRI may be considered in providing a less extensive surgery.

The Role of Femoral Head Size and Femoral Head Coverage in Dogs with and without Hip Dysplasia.

The subject of hip dysplasia in dogs is still current and preoccupies both animal owners and veterinarians. Major factors affecting the development of the disorder are hip laxity and incongruent joints. Many studies on etiology, pathogenesis, and early diagnosis have been performed to reduce prevalence and select healthy dogs for breeding. The purpose of the present study was to investigate a possible relationship between dysplasia and femoral head area (FHA), femoral coverage by the acetabulum (CFH) and cranio-caudal distance of the dorsal acetabular rim (CrCdAR). Radiographs of a total of 264 skeletally mature dogs with similar physical characteristics (German wirehaired pointers (GWP), German shepherd dogs (GSD) and Labrador retrievers (LAB)) presented for routine hip dysplasia screening were recruited for the study. FHA, CFH and CrCdAR were measured and related to dysplasia status. Evaluations of FHA (p = 0.011), CFH (p < 0.001) and CrCdAR length (p = 0.003) measurements revealed significant interactions between breed, sex and FCI scores, so they had to be assessed separately. The results revealed that FHA tends to decrease as the hip dysplasia score worsens. There was no significant relationship between FHA and dysplasia assessment. FHA is breed-specific and is larger in normal and near-normal male (p = 0.001, p = 0.020) and female (p = 0.001, p = 0.013) GWP compared to GSD, respectively. FHA is greater in normal male GWP (p = 0.011) and GSD (p = 0.040) compared to females. There was a significant and strong positive correlation between FHA and CrCdAR in all breeds and sexes. Additionally, FCI scoring had a medium (GWP, GSD) to strong (LAB) negative correlation with CFH.

On the feasibility of cardiac substructure sparing in magnetic resonance imaging guided stereotactic lung radiotherapy.

Lung stereotactic body radiotherapy (SBRT) has proven an effective treatment for medically inoperable lung tumors, even for (ultra-)central tumors. Recently, there has been growing interest in radiation-induced cardiac toxicity in lung radiotherapy. More specifically, dose to cardiac (sub-)structures (CS) was found to correlate with survival afterradiotherapy. Our goal is first, to investigate the percentage of patients who require CS sparing in an magnetic resonance imaging guided lung SBRT workflow, and second, to quantify how successful implementation of cardiac sparing would be. The patient cohort consists of 34 patients with stage II-IV lung cancer who were treated with SBRT between 2017 and 2020. A mid-position computed tomography (CT) image was used to create treatment plans for the 1.5 T Unity MR-linac (Elekta AB, Stockholm, Sweden) following clinical templates. Under guidance of a cardio-thoracic radiologist, 11 CS were contoured manually for each patient. Dose constraints for five CS were extracted from the literature. Patients were stratified according to their need for cardiac sparing depending on the CS dose in their non-CS constrained MR-linac treatment plans. Cardiac sparing treatment plans (CSPs) were then created and dosimetrically compared with their non-CS constrained treatment plan counterparts. CSPs complied with the departmental constraints and were considered successful when fulfilling all CS constraints, and partially successful if some CS constraints could be fulfilled. Predictors for the need for and feasibility of cardiac sparing were explored, specifically planning target volume (PTV) size, cranio-caudal (CC) distance, 3D distance, and in-field overlap volume histograms (iOVH). 47% of the patients (16 out of 34) were in need of cardiac sparing. A successful CSP could be created for 62.5% (10 out of 16) of these patients. Partially successful CSPs still complied with two to four CS constraints. No significant difference in dose to organs at risk (OARs) or targets was identified between CSPs and the corresponding non-CS constrained MR-linac plans. The need for cardiac sparing was found to correlate with distance in the CC direction between target and all of the individual CS (Mann-Whitney U-test p-values <10-6 ). iOVHs revealed that complying with dose constraints for CS is primarily determined by in-plane distance and secondarily by PTVsize. We demonstrated that CS can be successfully spared in lung SBRT on the MR-linac for most of this patient cohort, without compromising doses to the tumor or to other OARs. CC distance between the target and CS can be used to predict the need for cardiac sparing. iOVHs, in combination with PTV size, can be used to predict if cardiac sparing will be successful for all constrained CS except the leftventricle.

The robustness of glenohumeral centering measurements in dependence of shoulder rotation and their predictive value in shoulders with rotator cuff tears

ObjectiveDe-centering of the shoulder joint on radiographs is used as indicator for severity of rotator cuff tears and as predictor for clinical outcome after surgery. The objective of the study was to assess the effect of malrotation on glenohumeral centering on radiographs and to identify the most reliable parameter for its quantification.Subjects and methods.In this retrospective study (2014–2018), 249 shoulders were included: 92 with imaging-confirmed supra- and infraspinatus tears (rupture; 65.2 ± 9.9 years) and 157 without tears (control; 41.1 ± 13.0 years). On radiographs in neutral position and external rotation, we assessed three radiographic parameters to quantify glenohumeral centering: acromiohumeral distance (ACHD), craniocaudal distance of the humeral head and glenoid center (Deutsch), and scapulohumeral arch congruity (Moloney). Non-parametric statistics was performed.ResultsIn both positions, only the distance parameters ACHD (< 0.5 mm) and Deutsch (< 1 mm) were comparable in the two study groups rupture and control. Comparing the parameters between the study groups revealed only ACHD to be significantly different with a reduction of more than 2 mm in the rupture group. Among the parameters, ACHD ≤ 6 mm was the only cut-off discriminating rupture (12–21% of the shoulders with ACHD ≤ 6 mm) and control (none of the shoulders with ACHD ≤ 6 mm). Ninety percent of shoulders with ACHD ≤ 6 mm presented with a massive rotator cuff tear (defined as ≥ 67% of the greater tuberosity exposed).ConclusionGlenohumeral centering assessed by ACHD and Deutsch is not affected by rotation in shoulders with and without rotator cuff tear. An ACHD ≤ 6 mm has a positive predictive value of 90% for a massive rotator cuff tear.

Localization of the Sphenopalatine Ganglion Within the Pterygopalatine Fossa on Computed Tomography Angiography—A Potential Role in the Setting of Sphenopalatine Ganglion Microstimulator Implantation

A recent approach to treatment of cluster headaches (CH) employs a microstimulator device for on-demand neuromodulation of the sphenopalatine ganglion (SPG) during an acute CH attack. A precise anatomical localization of the SPG within the pterygopalatine fossa (PPF) is optimal in order to position the SPG electrode array. This study aims to investigate a novel approach for SPG localization using computed tomography angiographic studies (CTA). Two independent observers identified the location of the SPG on 54 computed tomography angiographic studies (CTA) and measured its position relative to the vidian canal (VC). The qualitative confidence of identification, morphology, position within the PPF and its relation to vascular structures were also recorded. The SPG was detectable in 88% of cases with a variable position. The most frequent positions were superior (56%) and lateral (99%) relative to the VC with a mean (±SD) craniocaudal distance of 0.34 mm (±1.38) and a mean mediolateral distance of 3.04 mm (±1.2). However, in a considerable proportion of cases, the SPG was identified inferiorly to the VC (33%). Interobserver and intraobserver agreement for SPG location were moderate and strong respectively. Since localization of SPG on CTAs is feasible and reproducible, it has future clinical potential to aid placement, optimal positioning and individualized programming of the electrode array.

Ovarian Transposition Before Pelvic Radiation Therapy: Spatial Distribution and Dose Volume Analysis

PurposeThere is a paucity of data analyzing the anatomic locations and dose volume metrics achieved for surgically transposed ovaries in patients desiring fertility or hormonal preservation receiving pelvic radiation therapy (RT), which were examined herein. Methods and MaterialsThis is a retrospective study including women who underwent ovarian transposition before pelvic RT between 2010 to 2020. The craniocaudal (CC) distance of the ovary centroid to the (1) plane of the sacral promontory, (2) iliac crest, and (3) the nearest distance between the ovary edge and RT planning target volume (PTV) were measured (cm). The area under the receiver operating characteristic curve and cut-point analysis estimating ovary location outside the PTV was performed. ResultsThirty-one ovaries were analyzed from 18 patients. Thirteen (72.2%) were treated with intensity modulated RT, and 5 (27.8%) were treated with 3-dimensional conformal radiation therapy. Most ovaries were located above the sacral promontory (64.5%, n = 20), below the iliac crest (96.8%, n = 30), and outside the PTV (64.5%, n = 20). The median distance from the ovaries to the sacral promontory, iliac crest, and PTV was 0.8 cm (interquartile range [IQR], −0.83 to 1.59 cm), −3.22 cm (IQR, −5.12 to −1.84 cm), and 0.9 cm (IQR, −1.0 to 1.9 cm), respectively. The area under the receiver operating characteristic curve and cut-point analysis demonstrated that distance from the iliac crest predicted an ovary to be outside the PTV with an optimal cut-point of −3.0 cm (C-index = 0.82). The median mean and maximum (Dmax) ovary doses were 15.5 Gy (IQR, 9.6-20.2 Gy) and 32.2 Gy (IQR 24.8-46.5 Gy), respectively. ConclusionsDespite most transposed ovaries being located outside the PTV, nearly all remained below the iliac crest and received RT doses associated with a high risk of ovarian failure. These findings deepen our understanding of the spatial relationship between transposed ovaries and dose to inform surgical and pre-RT planning and suggest that more aggressive ovary-sparing strategies are warranted.

Ovarian Transposition Prior to Pelvic Radiotherapy: Spatial Distribution and Dose Volume Analysis

<h3>Purpose/Objective(s)</h3> Pelvic radiotherapy (RT) is an integral component of local therapy for anorectal and gynecologic malignances. Ovaries are exquisitely radiosensitive, with even 6 Gy exposure leading to a moderate risk of ovarian failure, and 14 Gy resulting in ovarian failure in nearly all patients. To facilitate ovary dose reduction, surgical transposition prior to pelvic RT can be performed, however ovarian function preservation rates remain approximately 50%. Moreover, there is a paucity of data in the modern treatment era analyzing the anatomic locations and dose volume metrics achieved for transposed ovaries, which was examined herein. <h3>Materials/Methods</h3> Retrospective study including women who underwent ovarian transposition prior to pelvic RT between 2010 and 2020. Measurements (cm) were obtained for 1) the craniocaudal (CC) distance from the plane of the sacral promontory to the ovary centroid and 2) the distance between the nearest edge of the ovary and RT planning target volume (PTV) in any dimension. Area under the receiver operating characteristic curve (AUC) and cut-point analysis estimating ovary location outside the PTV was performed. <h3>Results</h3> Thirty-one ovaries were analyzed from 18 patients. Fourteen (77.8%) were treated for cervical cancer and three (16.7%) for rectal cancer. Most (72.2%, n = 13) were treated with intensity-modulated RT while 27.8% (n = 5) were treated with 3D-CRT. The median CC distance from the ovaries to sacral promontory was 0.8 cm (interquartile range [IQR] -0.83 - 1.59 cm) and the median distance between the ovary and PTV was 0.9 cm (IQR, -1.0 - 1.9 cm). The majority of ovaries were located above the sacral promontory (64.5%, n = 20) and outside the PTV (61.3%, n = 19). AUC and cut-point analysis demonstrated that CC distance from the sacral promontory predicted an ovary to be outside the PTV with an optimal cut-point of 1.2 cm (C-index = 0.72). The median mean and maximum (Dmax) ovary doses were 15.5 Gy (IQR, 9.6 - 19.4 Gy) and 32.2 Gy (IQR, 24.8 - 45.9 Gy), respectively. When comparing the RT dose of transposed ovaries located outside (n = 19) vs. within (n = 12) the PTV, there was a significant decrease in median Dmax (25.4 Gy vs. 46.1 Gy; <b>P</b> < .001), but no significant difference in median mean dose (15.5 Gy vs. 16.4 Gy; <b>P</b> = .19). There was a significant inverse correlation between CC distance of transposed ovaries to the sacral promontory and ovary mean dose (-0.73, <b>P</b> < .0001) and Dmax (-0.76, <b>P</b> < .0001). <h3>Conclusion</h3> There was a significant inverse correlation between ovary CC distance from the sacral promontory and ovary RT dose. However, despite the majority of transposed ovaries being located outside the PTV, most patients still received ovary doses associated with a high risk of ovarian failure. These findings provide a deeper understanding of the relationship between ovary location and dose to inform pre-RT planning and suggest that more aggressive ovary-sparing strategies are warranted.

Ex vivo Evaluation of the Dynamic Morphometry of the Caudal Cervical Intervertebral Disc Spaces of Small Dogs and Cats.

The objective of this study was to provide a morphometric description of the caudal cervical intervertebral disc (IVD) spaces of small-breed dogs and cats. Specimens consisting of C4 through C7 from five small-breed dogs and six cats were positioned in neutral, flexion, extension, and lateral bending positions; and CT images were acquired. Height and width of the cranial and caudal vertebral endplates (VEPs), angle between the VEPs (IVD wedge angle), and craniocaudal distance (IVD width) between VEPs for the four loading positions were measured and compared for three segments (C4–C5, C5–C6, and C6–C7). VEP size normalized to body weight from medium-sized dogs was retrieved from a previous study and compared with data from small dogs and cats. A linear mixed model was used to compare outcome measures. Significance was set to p < 0.05. VEP size normalized to body weight was the largest in small dogs compared with cats (p = 0.0422) and medium-sized dogs (p = 0.0064). Cats and medium-sized dogs were similar (p = 0.2763) in this regard. Flexion and extension induced a reduction of IVD width in the ventral portion of the IVD and the area of the nucleus. The dorsal part of the IVD remained unchanged throughout loading conditions. Unique morphometric characteristics of the caudal cervical IVD space of small dogs and cats were detected that are different from those described in sizes of dogs (medium-sized) typically affected by caudal cervical spondylomyelopathy (CSM). These findings may help to understand the different pathomechanisms in cervical spinal disease between small- and medium-sized dogs, including caudal CSM.

In vivo 3D tomography of the lumbar spine using a twin robotic X-ray system: quantitative and qualitative evaluation of the lumbar neural foramina in supine and upright position

ObjectivesSupine lumbar spine examinations underestimate body weight effects on neuroforaminal size. Therefore, our purpose was to evaluate size changes of the lumbar neuroforamina using supine and upright 3D tomography and to initially assess image quality compared with computed tomography (CT).MethodsThe lumbar spines were prospectively scanned in 48 patients in upright (3D tomographic twin robotic X-ray) and supine (30 with 3D tomography, 18 with CT) position. Cross-sectional area (CSA), cranio-caudal (CC), and ventro-dorsal (VD) diameters of foramina were measured by two readers and additionally graded in relation to the intervertebral disc height. Visibility of bone/soft tissue structures and image quality were assessed independently on a 5-point Likert scale for the 18 patients scanned with both modalities. Descriptive statistics, Wilcoxon’s signed-rank test (p < 0.05), and interreader reliability were calculated.ResultsNeuroforaminal size significantly decreased at all levels for both readers from the supine (normal intervertebral disc height; CSA 1.25 ± 0.32 cm2; CC 1.84 ± 0.24 cm2; VD 0.88 ± 0.16 cm2) to upright position (CSA 1.12 ± 0.34 cm2; CC 1.78 ± 0.24 cm2; VD 0.83 ± 0.16 cm2; each p < 0.001). Decrease in intervertebral disc height correlated with decrease in foraminal size (supine: CSA 0.88 ± 0.34 cm2; CC 1.39 ± 0.33 cm2; VD 0.87 ± 0.26 cm2; upright: CSA 0.83 ± 0.37 cm2, p = 0.010; CC 1.32 ± 0.33 cm2, p = 0.015; VD 0.80 ± 0.21 cm2, p = 0.021). Interreader reliability for area was fair to excellent (0.51–0.89) with a wide range for cranio-caudal (0.32–0.74) and ventro-dorsal (0.03–0.70) distances. Image quality was superior for CT compared with that for 3D tomography (p < 0.001; κ, CT = 0.66–0.92/3D tomography = 0.51–1.00).ConclusionsThe size of the lumbar foramina is smaller in the upright weight-bearing position compared with that in the supine position. Image quality, especially nerve root delineation, is inferior using 3D tomography compared to CT.Key Points• Weight-bearing examination demonstrates a decrease of the neuroforaminal size.• Patients with higher decrease in intervertebral disc showed a narrower foraminal size.• Image quality is superior with CT compared to 3D tomographic twin robotic X-ray at the lumbar spine.

Analysis of Correlation Between Breast Surface Position and Internal Organ Deformation Using Deep-Inspiration Breath Holding for Left-Sided Breast Irradiation

An increased risk of cardiac toxicity and radiation pneumonitis is related to the mean dose of radiation to the heart and lungs during left-sided breast irradiation. The deep-inspiration breath holding (DIBH) technique was investigated with focus on reducing the radiation dose to the heart and its substructures, such as the left anterior descending coronary artery (LAD). Three-dimensional surface-imaging systems have been used to facilitate image-guided breast radiotherapy. However, internal organ position during DIBH depends on the compliance of the patient. Previous research has shown that relative craniocaudal distance changes during inspiration and expiration normalized to the mean distance in quiet breathing was maximum 44.3% ± 4% and minimum 4% ± 5%. We investigated positional correlations between limited breast surface position and internal organs and evaluated the effect of doses in left-sided breast irradiation with the DIBH technique. In this study, breast surface position was measured using an infrared range finder and the heart position was retrospectively measured using CT data. Five patients who had undergone left-sided lumpectomy practiced DIBH during CT. Simultaneously, breast surface distance (BSD) was monitored by a range finder continually during CT acquisition. The range finder was attached to the CT couch and measured the distance from one point of the breast surface to the scanner. CT with voluntary DIBH and free breathing in the treatment position was performed three times in each patient. To measure heart distances (HD), the maximum distance from the LAD to the chest wall (lateral edge of the lung) was calculated in each CT image and associated with the location to the corresponding BSD. Each free-breathing CT image was deformed to each DIBH CT image, and the deformation vector field (DVF), which was associated with the HD and the BSD, was calculated. Moreover, we evaluated dosimetric effects of variations of internal organ deformation by the voluntary DIBH. Compared with the mean BSD during free breathing, mean BSD during DIBH was reduced by 12 mm and the reproducibility was shown to be stable at approximately ± 0.2～3.9 mm. The mean HD was increased by 5.4 ± 2.4 mm. The correlation coefficient between BSD and HD during DIBH was 0.23, which indicated a weak positive correlation. According to the results of DVF, the heart and diaphragm positions moved forward toward the front caudal side; however, the variation in HD and internal organ motion depended on the characteristics of each patient. Moreover, in cases of abdominal breathing, breast surface motion was significantly small and no correlation between BSD and HD was observed. However, dosimetric errors of target and normal tissue were small, suggesting that DIBH irradiation while monitoring BSD is feasible. Correlations among BSD, HD, and internal organ motion were weak and depended on patient characteristics and respiratory method.

Course of the thoracic nerves around the umbilicus within the posterior layer of the rectus sheath: a cadaver study.

Rectus sheath block is used to anesthetize thoracic nerves around the umbilicus. However, the appropriate point for anesthetic injection during rectus sheath block has not been determined anatomically. Here, we examined the course of thoracic nerve T10 at the posterior layer of the rectus sheath and the anatomical relationship between the nerve and the rectus abdominis and transversus abdominis muscles in formalin-fixed adult cadavers. The cranio-caudal distance from a horizontal line running through the umbilicus to where the thoracic nerve T10 passes through the posterior layer of the rectus sheath was 33.8 ± 14.4 (mean ± standard deviation) mm, while that from the horizontal line running through the umbilicus to the position where the lateral edge of the rectus abdominis muscle and the medial border of the transversus abdominis muscle cross was 33.1 ± 17.1mm. The position where the lateral edge of the rectus abdominis muscle and the medial border of the transversus abdominis muscle cross approximates the position where thoracic nerves T10 passes through the posterior layer of the rectus sheath. Our results identify effective landmarks to guide the performance of rectus sheath block.

Ex vivo computed tomography evaluation of loading position on morphometry of the caudal cervical intervertebral disk spaces of dogs.

OBJECTIVE To provide an objective, quantitative morphometric description of the caudal cervical intervertebral disk (IVD) spaces of dogs. SAMPLE Vertebral specimens consisting of C4 through C7 from 5 medium-sized dogs. PROCEDURES CT images were obtained with the specimens positioned in neutral, flexion, extension, and lateral bending positions. Size and shape of the cranial and caudal end plates, angle between the end plates (IVD wedge angle), and craniocaudal distance (IVD width) between end plates for the 4 loading positions were measured and compared for the 3 segments (C4-5, C5-6, and C6-7). RESULTS End plate size and shape, IVD wedge angle, and IVD width were not significantly different among the 3 segments. Caudal cervical end plates were consistently larger than cranial cervical end plates. The IVD wedge angle ranged from -4.8° to 15.2°. Flexion induced a reduction in IVD width in the ventral portion of the IVD, whereas extension induced a decrease in width in the dorsal portion of the IVD. Central IVD width remained unchanged among the loading positions. CONCLUSIONS AND CLINICAL RELEVANCE Unique morphometric and dynamic characteristics of the caudal cervical IVD space of dogs were detected. These findings may help investigators when designing IVD prostheses for dogs with cervical spondylomyelopathy.

Quantitative Analysis of Surgical Working Space During Endoscopic Skull Base Surgery

Objectives Selective dissection of intranasal anatomy may improve visualization and maneuverability at the skull base. We aimed to quantify the dimensions of working space and angles achieved following sequential removal of intranasal structures using an endoscopic transphenoidal approach to the skull base. Methods Cone beam computed tomography scans of four cadaveric heads were obtained for registration of an optical tracking system. Each head was sequentially dissected: (1) sphenoidotomy and limited posterior septectomy, (2) unilateral partial middle turbinectomy, (3) bilateral partial middle turbinectomy, and (4) wide posterior septectomy. The maximal craniocaudal and mediolateral distance (mm) and angle (degrees) reached were calculated at the sphenoid face and sella. Data were analyzed using descriptive statistics and tests of statistical significance. The significance level was set at p ≤ 0.05. Results A significant improvement in both dimensions of working space was observed with each stage of dissection at the level of the sphenoid face. Maximal working space was achieved following bilateral middle turbinectomy and wide posterior septectomy with a 38 and 29% increase in working space in the mediolateral and craniocaudal dimensions, respectively. The largest stepwise increase in working space was observed with unilateral middle turbinectomy (mediolateral: 24 ± 3 mm and craniocaudal: 20 ± 3 mm). A trend toward improved degrees of visualization was observed with each stage of dissection but was not statistically significant. Conclusion Approaches to the skull base can be enhanced by selective unilateral/bilateral partial middle turbinectomy and posterior septectomy being performed to improve visualization and maximize surgical working freedom.

Prognosis of Hormonal Deficits in Empty Sella Syndrome Using Neuroimaging.

Aim:We have evaluated the anatomic measurements on sellar area of patients who were radiologically diagnosed with empty sella to determine the relation between the amount of pressure on the adenohypophysis and hormonal imbalances.Materials and Methods:Sixty-one cases were diagnosed with empty sella and had hormone tests and hypophysis magnetic resonance (MR). The cases were categorized into two groups – patients with hypophyseal hormone anomaly and patients without hormone anomaly. We have measured interclinoid distance, anteroposterior distance from the anterior diaphragm sella to the pituitary stalk, depth of the sella turcica, craniocaudal distance of the optic chiasm from the diaphragm sella, the heights of the right and left adenohypophysis, subcutaneous fat thickness measured orthogonal to the coronal suture and posteriorly at the level of C2–C3 for two groups on hypophysis and cranial MR imaging MRI.Results:Twenty-five hormone-positive cases (40.9%) (hormone test were abnormal) and 36 hormone-negative cases (59.1%) (hormone tests were normal) were included in the study. The most common hormone abnormality was thyroid-stimulating hormone, T3 and T4 deficiency in 12 cases (48%) and increase in prolactin level in 7 cases (28%). Right adenohypophysis height was 1.54 ± 0.840 mm for the 1st group, and 1.96 ± 0.83 mm for the 2nd group. The left adenohypophysis height was 1.66 ± 0.80 mm for the 1st group, and 1.94 ± 0.94 mm for the 2nd group. It was found out that the thickness at right and left side in the hormone-positive group diminished significantly.Conclusion:Adenohypophysis height and distance between stalk and optic nerve were good determiner for hormone defect.