OsiriX Software Research Articles

Pre-operative low muscle mass is associated with major complications and lower recurrence-free survival after gastric cancer surgery.

Low muscle mass (LMM) has been associated with post-operative morbidity. This study aimed to examine the relationship between pre-operative LMM and major post-operative complications and survival in patients undergoing curative resection for gastric cancer. A single-centre retrospective cohort study was conducted on consecutive patients who underwent surgical resection for gastric adenocarcinoma between 2008 and 2018. Patient demographics, radiological parameters, pathological data and complications were recorded. Skeletal muscle index was calculated using OsiriX software by manually measuring the cross-sectional skeletal muscle area at the third lumbar vertebra and correcting to the patient's height. Univariate and multivariate analyses were used to identify the risk factors associated with the outcomes. A total of 62 patients (36 males, mean age 68.3 ± 1.5 years) met the inclusion criteria. Twenty-six (41.9%) patients had LMM pre-operatively. Demographic data in the non-LMM and LMM groups were equally matched except for body mass index (27.6 ± 0.8 kg/m2 versus 24.3 ± 1.1 kg/m2 ; P = 0.012) and serum albumin (36.7 ± 0.7 g/L versus 33.8 ± 1.0 g/L; P = 0.017), which were higher in the non-LMM. LMM was associated with higher incidence of total (35.5% versus 64.5%; P = 0.006), minor (40% versus 60%; P = 0.030), major (9.1% versus 90.9%; P = 0.004) post-operative complications and decreased recurrence-free survival (hazard ratio 2.29; 95% confidence interval 1.10-4.77; P = 0.027). LMM is a significant independent risk factor for major post-operative complications and recurrence-free survival after gastrectomy. Pre-operative identification of LMM could be a useful tool for prognostication and may identify a group suitable for prehabilitation.

Prostatic artery embolization: magnetic resonance image (MRI) findings in the early detection of prostate infarction in a canine spontaneous benign prostatic hyperplasia model.

BackgroundThe purpose was to assess the association between prostate infarction and prostate volume (PV) reduction after prostatic artery embolization (PAE) and define the best time point in detection of prostate infarction.MethodsTen male beagles (3.5–6.4 years) with spontaneous benign prostatic hyperplasia (BPH) underwent PAE. Magnetic resonance image (MRI) was conducted immediately before and 1 week, 2 weeks and 1 month after PAE to document prostate infarcts and measure PV. The sum of infarct areas (SUMIA) was measured and calculated using OsiriX software. Spearman’s rank correlation was used to estimate the relationship of PV reduction rate with infarction percentage and SUMIA reduction.ResultsIn comparison with baseline data, significant PV reduction (P<0.001) occurred at 2 weeks and continued to decrease substantially (P=0.004) from 2 weeks to 1 month after PAE. In the same fashion, significant decrease in both SUMIA and infarction percentage was observed from 1 to 2 weeks (P=0.002), and subsequently to 1 month (P=0.039 and P=0.016, respectively). Spearman’s rank correlation test demonstrated infarction percentage at 1 week had a stronger correlation (r=0.880, P=0.001) with PV reduction rate at 1 month than infarction percentage at 2 weeks (r=0.733, P=0.016). PV reduction rate had a significant correlation with decrease in SUMIA (r=0.854, P=0.002) at 1 month after PAE.ConclusionsOne week after PAE is an ideal time point to evaluate prostate infarction. Prostate infarction percentage at 1 week is a good predictor for prostate shrinkage at 1 month after PAE.

Intra- and Interobserver Reliability of Bone Volume Estimation Using OsiriX Software in Patients with Cleft Lip and Palate Using Cone Beam Computed Tomography.

The objective of the current study was to evaluate intra- and interobserver bone volume measurements and effect of orientation on the reliability of bone volume evaluation in as-acquired vis-à-vis oriented cone beam computed tomography scans using Osirix software and possible correlation between gender, age, and bone volume required. For this, 31 cone beam computed tomography (CBCT) scans of 14 girls and 17 boys (aged 9–13) with unilateral cleft lip and/or palate who met the inclusion criteria were analyzed. Efficacy and reliability of third party software Osirix for bone volume calculation was assessed using as acquired and oriented volumes by three specialists (a radiologist, an orthodontist, and an oral maxillofacial surgeon). The dataset and readings were anonymized to prevent any bias. Two-way mixed model analysis on as-acquired and oriented observations exhibited intra-class coefficient (ICC) values ≥ 0.90. Wilcoxon signed rank test (p = 0.10) and Kruskal–Wallis ANOVA (p = 0.46) indicated that although a clinical difference in volume assessment was seen between as-acquired and oriented observations (inter-observer and intra-observer), it was statistically insignificant. Spearman’s bi-variate correlation analysis revealed a significant relation between the type (side) of cleft and bone volume required to fill the defect (p < 0.05). Although there was clinical difference in bone volume measurement by the three observers, it was insignificant statistically. Clefts on the left side in the patients had significantly more bone required than the right side, whereas age and gender had no relation with bone needed to fill the defect. OsiriX software provided good reliability in measurements of bone volume.

Anterior epitympanic recess volume and Cog process length in temporal bones with Körner's septum: A radio- anatomical investigation

ObjectiveKörner's septum is a dense bony lamina dividing the mastoid cavity into superficial squamous and deeper petrosal portions at the level of antrum. In this study, we aimed at investigating the association of the Körner's septum with the length of the Cog process and the volume of anterior epitympanic recess (AER), using the 3-dimensional reconstruction models based on high resolution computed tomography sections of the temporal bone. MethodsUsing OsiriX software for MacOS (version 3.8.1, Pixmeo), we measured the volumes from three- dimensional models of anterior epitympanic recess. Anterior epitympanic recess volumes and Cog process lengths of the temporal bones with and without Körner's septum were compared. ResultsCog process length was significantly higher, and AER volume was significantly lower in patients with Körner's septum compared to the patients without. (p < 0.001). Additionally, Cog process length was significantly (p = 0.008), negatively, but weakly (rho= −0.24) correlated with AER volume. ConclusionTemporal bones with Körner's septum had a longer Cog process and a smaller AER.

Volume quantification of endolymphatic hydrops in patients with vestibular schwannoma

ObjectiveThe origin of vestibular symptoms in patients with vestibular schwannoma (VS) is uncertain. We used intratympanic gadolinium-enhanced magnetic resonance imaging (MRI) to confirm the labyrinthine lesions in patients with VS and to explore the features of endolymphatic hydrops (EH) in these patients. MethodsIn total, 66 patients diagnosed with unilateral VS were enrolled in this study and underwent intratympanic gadolinium-enhanced MRI. The borders of the vestibule and endolymph were mapped on the axial MRI images, and the area and volume of vestibule and endolymph were automatically calculated using Osirix software, and the area and volume percentage of vestibular endolymph were obtained. ResultsThe area and volume percentages of vestibular endolymph on the affected side were significantly larger than those on the healthy side (both p < 0.001). Using Kendall's W test, we found that the area and volume percentages of vestibular endolymph on the affected side were consistent (p < 0.001), but the consistency was moderate (k = 0.574). The healthy side was also consistent (p < 0.001), and the degree of consistency was moderate (k = 0.444). We used 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH; that is, the volume percentage of vestibular endolymph that was more than 19.1% were defined as the subgroup with hydrops, while the subgroup without hydrops included patients with a baseline level below 19.1%. No volume classification for vestibular EH was proposed. Based on this standard, 11/66 (16.7%) of the patients with VS in this study had vestibular EH. Conclusions.The volume percentage of the vestibular endolymph was more accurate than the area percentage for assessing vestibular EH. Using 19.1% as the cut-off point to distinguish the presence or absence of vestibular EH, we found that 16.7% of patients with VS had varying degrees of vestibular EH. We believe that the vestibular symptoms in patients with VS may originate from the peripheral lesions.

Endovascular treatment of common iliac artery aneurisms

To demonstrate endovascular management of common iliac artery aneurysms with iliac branch devices and to discuss some technical aspects of these interventions including bilateral procedures. Endovascular abdominal aortic aneurysm repair with concomitant implantation of iliac branch devices was performed in 9 patients at the Petrovsky National Research Center of Surgery for the period from January 2019 to December 2020. Mean age of patients was 64.8± years (min 52; max 72 years). Preoperative planning and morphometric analysis were based on CT data with a slice thickness of 1 mm. Angiographic reconstruction was made using Osirix 3D software (OsiriX Foundation, Geneva, Switzerland). Abdominal aortic aneurysm was combined with common iliac artery aneurysm in 7 patients (77.7%). Three (33.3%) patients had isolated common iliac artery aneurysm without significant abdominal aorta enlargement (Reber type I). Bilateral common iliac artery aneurysms were detected in 1 (11.1%) patient. All patients had iliac artery aneurysms over 4 cm. Iliac branch device implantation was accompanied by endovascular abdominal aneurysm repair in all patients. Technical success rate was 100%. Six-month results were followed-up in 5 patients (55.5%), annual outcomes - in 2 patients (22.2%). Control examination consisted of a telephone interview, ultrasound of abdominal aorta, pelvic and lower limb arteries and computed tomography. All patients had no endoleaks, stent-graft thrombosis, as well as signs of ischemia of pelvic organs and lower extremities. Incidence of iliac artery aneurysm combined with abdominal aortic aneurysms is about 20%. Until recently, treatment of these patients was performed exclusively with covering of internal iliac artery. Improvement of technologies and development of iliac branch devices made it possible to preserve blood flow in internal iliac artery after endovascular management. This approach allowed avoiding of ischemic complications associated with embolization of internal iliac arteries.

Inter-Software and Inter-Scan Variability Amongst Post-Processing Software Platforms in Measurement of Epicardial Adipose Tissue

There is lack of standardisation of post-processing software platforms in the assessment of epicardial adipose tissue (EAT) on cardiac computed tomography (CT). This study assessed the inter-vendor agreement of EAT volume (EATv) and attenuation (EATa) on both contrast-enhanced (CE) and non-contrast CT (NCT) using freeware imaging software (OsiriX), EAT research-specific software (QFAT), and standard coronary CT reporting software (Vitrea).

Effect of postoperative radiotherapy for free flap volume changing after tongue reconstruction.

The purpose of this study was to evaluate the effect of postoperative radiotherapy (RT) on temporal volume changes with a cutaneous free flap (CF) and a myocutaneous free flap (MCF). The subjects were 24 men and 11 women (mean age, 50.5 ± 15.5years) with tongue or floor of mouth cancer. Twenty-seven cases of CF and eight cases of MCF were selected. The flap volume change of the reconstructed tongue was calculated using computed tomography (CT) images taken immediately and at one year postoperatively using the DICOM image processing software OsiriX®. The reduction rate in flap volume at one year postoperatively was 82.0 ± 15% in CF without RT, 70.3 ± 26.1% in CF with RT, 88.5 ± 14.7% in MCF without RT, and 99.5 ± 16% in MCF with RT. The MCF volume was significantly higher compared to the CF volume. Although postoperative RT reduced the CF volume by 30%, there was only a slight reduction in the MCF volume. We evaluated the effect of postoperative RT on volume reduction in 35 cases of the reconstructed tongue with CF and MCF using a computer-assisted volume rendering technique. In this study, the effect of RT on volume reduction was different between the CF and MCF.

Anatomical variants of the celiac trunk

Determine the anatomical variants of the celiac trunk and describe it in its modal form using a scanner. In total, 200 patients were included in this study. The study was carried out using a multi-detector scanner (SIEMENS Somatom Emotion Excel Edition, 16 bars). The two-dimensional and three-dimensional reconstructions by volume were made with the OSIRIX software. It was a retrospective study. The study had taken into account the result of the abdominal scanners injected carried out from December 15, 2018 to February 15, 2019 i.e. 14 months (1 year 2 months). A predominance of type I of UFLACKER is 93.50% with a rate of change from normal of 6.50%. A vertebral projection of the origin of the celiac trunk at the level of the T12-L1 intervertebral disc was observed in 52.80%. An existence of collateral branches in 7.5% of cases. Other terminal branches apart from the three classics were found in 8.5% of the cases. These variants deserve special attention in the case of a pre-therapeutic vascular assessment for the surgical or interventional management of tumors and trauma of the supra-meso-colic viscera or even for organ transplantation.

Peritoneal cavity circumference on computed tomography predicts outcomes in acute pancreatitis

ObjectivesWe investigated the role of novel intra-abdominal parameters measured by computed tomography (CT) in the prediction of clinical outcomes in acute pancreatitis (AP). MethodsPatients with AP underwent an abdominal CT scan on admission to define different intra-abdominal parameters (abdominal circumference, peritoneal cavity circumference, intraabdominal visceral fat area, and subcutaneous fat area) at the L2-L3 level using the open-source image analysis software Osirix Lite v.11.0.4 to predict clinical outcomes. ResultsEighty patients with AP were analyzed. Peritoneal cavity circumference (PCC) was the only variable independently associated with outcomes. PCC showed an area under ROC for prediction of severity in AP of 0.830. A PCC ≥ 85 cm increased the risk of severity of AP (RR 15.7), persistent systemic inflammatory response syndrome (RR 9.3), acute peripancreatic fluid collection (RR 6.4), necrotizing pancreatitis (RR 21.50), and mortality (RR 2.4). We found a 4.7-fold increase in the risk of developing severe AP for each 10 cm increase in PCC. ConclusionsPCC measurement at the L2-L3 level using a non-enhanced abdominal CT scan on admission in patients with AP is useful in the early prediction of severity, persistent systemic inflammatory response syndrome, local complications, and mortality.

Impact of Total Psoas Area and Lean Muscular Area on Mortality after Endovascular Aortic Aneurysm Repair

Sarcopenia has assumed growing relevance as a morbimortality predictor after major abdominal surgery. The aim of this study is to access total psoas muscle area (TPA) and lean muscle area (LMA) impact in morbimortality after elective endovascular abdominal aortic aneurysm repair (EVAR). Asymptomatic patients submitted to aortic endoprosthesis implantation between January 1, 2014 and December 31, 2018 at our vascular surgery department were retrospectively evaluated. After exclusion criteria were applied, 105 patients were included in the study; preoperative computed tomography scans were evaluated using OSIRIX software (Bernex, Switzerland). Two observers independently calculated TPA at the most caudal level of the L3 vertebra and respective density, therefore calculating LMA. Patients were separated by tertiles with the lowest being considered sarcopenic and with higher muscle steatosis and compared with the higher tertiles. Patient demographics and intraoperative and postoperative period variables were collected. Charlson comorbidity index was calculated and surgical complications classified according to Clavien-Dindo. The intraclass correlation coefficient and Bland-Altman plot were made to characterize interobserver variability. Survival analysis was performed with the Kaplan-Meier method, and differences between survival curves were tested with the log-rank test. The effect of sarcopenia on patient survival was assessed using Cox proportional hazard models. Considering TPA, univariate analyses revealed that patients in the lower tertile had inferior survival (P=0.03), whereas multivariate analyses showed increased likelihood of mortality (P=0.039, hazard ratio (HR) 3.829). For LMA, univariate analyses revealed that patients in the lower tertile had inferior survival (P=0.013), whereas multivariate analyses showed increased likelihood of mortality (P=0.026, HR 4.153). When analyzing patients in the lowest tertile of both TPA and LMA, both univariate (P=0.002) and multivariate (P=0.018, HR 4.166) analyses reveled inferior survival. Our study reveals reduced survival in patients with low TPA and low LMA submitted to elective EVAR; these factors should probably be taken into consideration in the future for preoperative risk evaluation and surgical planning.

Changes of Ocular Dimensions as a Marker of Disease Progression in a Murine Model of Pigmentary Glaucoma.

PurposeThe elevation of intraocular pressure (IOP), a major risk factor in glaucoma, is an important parameter tracked in experimental models of this disease. However, IOP measurement in laboratory rodents is challenging and may not correlate with some key pathological events that occur in the development of glaucoma. The aims of this study were to quantify changes in ocular morphology in DBA/2J mice that develop spontaneous, age-dependent, pigmentary glaucoma and to check the possible correlation of these parameters with IOP.MethodEye morphology was evaluated with MRI in DBA/2J, DBA/2J-Gpnmb+/SjJ, and C57BL/6J female mice ages 3, 6, 9, 12, and 15 months. The animals were anesthetized with isoflurane. A planar receive-only surface coil (inner diameter = 10 mm) was placed over each animal’s left eye and the image was acquired with a 7T small animal-dedicated magnetic resonance tomograph and T2-weighted TurboRARE sequence. Ocular dimensions were manually quantitated using OsiriX software. IOP was measured with rebound tonometry.ResultsIn the control animals, no age-related changes in the ocular morphology were noted. Since 6 months of age, the anterior chamber deepening and elongation of the eyeballs of DBA/2J mice was detectable. We found a significant, positive correlation between IOP and axial length, anterior chamber area, or anterior chamber width in C57BL/6J mice but not in DBA/2J mice. However, after excluding the measurements performed in the oldest DBA/2J mice (i.e. analyzing only the animals ages 3 to 12 months), we demonstrated a significant positive correlation between IOP and anterior chamber width.ConclusionHigh-resolution magnetic resonance imaging of the eye area in mice enables reproducible and consistent measures of key dimensions of the eyeball. We observed age-dependent alterations in the eye morphology of DBA/2J mice that mostly affected the anterior chamber. We also demonstrated a correlation between some of the ocular dimensions and the IOP of C57Bl/6J mice and DBA/2J mice with moderately advanced glaucomatous pathology.

Contralateral adrenal thinning as a distinctive feature of mild autonomous cortisol excess of the adrenal tumors.

To identify radiologic features that correlate with mild autonomous cortisol excess using planar and volumetric analysis. Cross-sectional study. In the study, 64 patients with overt Cushing syndrome (CS), 59 patients with mild autonomous cortisol excess (MACE), and 64 patients with nonfunctioning adrenal tumors (NFAT) with evaluable CT scans were included. Patients with NFAT and MACE were BMI-matched with those with overt CS. Planar and volumetric analyses of CT scans were performed in DICOM images using OsiriX software. The mean age was 56.6 ± 1.01 years, and 123 patients (65.1%) were female. In the order of NFAT, MACE, and overt CS, the diameters and volumes of the adenoma increased, while limb widths and volumes of the contralateral adrenal gland decreased. Patients with MACE or overt CS were more likely to have osteoporosis than those with NFAT (P = 0.006), and patients with overt CS were more likely to experience a fragility fracture than those with NFAT or MACE (P = 0.002). Among radiologic features, the limb width of the contralateral adrenal gland correlated with the cortisol level after overnight dexamethasone suppression test (r = -0.583, P < 0.001). The study showed that the contralateral adrenal limb thinning was a distinctive radiologic feature of autonomous cortisol excess in the planar and volumetric analysis.

Difficult airways: a 3D printing study with virtual fibreoptic endoscopy

Head and neck cancer patients present unique airway challenges, and oropharyngeal, laryngeal, and hypopharyngeal tumours considerably distort and narrow the anatomy of the airway. We describe the use of 3D augmented reality software combined with 3D printed models to assess the anatomy of difficult airways and to assist in the formulation of the most optimal airway management strategy in such patients. The reported patients had computed tomograms (CT) of the neck prior to their anaesthetic and surgical management. DICOM files of the respective scans were imported to 3D rendering software (OsiriX, Pixmeo). We constructed volume rendered models for initial assessment of the airway then generated serial surface rendered models to create a virtual endoscopic path of the airway to simulate the fibreoptic approach. To further facilitate the study of difficult airways we have subsequently printed 3D models of those that were most difficult using rapid prototyping. Head and neck tumours significantly distort the airway. Thorough study of the relevant anatomy prior to airway management for operating reasons enhances communication between the surgeon and anaesthetist, and aids selection of the most appropriate intubation approach. In conclusion, this paper highlights a useful and novel pre-assessment strategy that allows a virtual, visual, 3-dimensional assessment of the airway anatomy combined with 3D modelling and 3D printing. This enables the airway specialist, anaesthetist, and head and neck surgeon to anticipate any critical steps and adjust the plan accordingly.

Long-term evaluation after autologous fat transplantation for breast augmentation

Background The transplantation of autologous fat is an increasingly common but not standardized procedure in aesthetic and reconstructive surgery. Until now only studies about the short-term results after transplantation with autologous fat have been published. In this publication we present our results of a long-term study after fat transplantation.Patients/Material and Methods 14 patients underwent an MRI investigation which was done before and 5-9 years (mean 6 years) years after aesthetic breast lipofilling according to BEAULI-protocol. The difference in volume was calculated with the open source software OsiriX. Two groups were analyzed separately to calculate the influence of body weight changes in final volume gain. In the first group patients with a stable BMI (increase of less than 1 kg/m2) were included. The second group includes patients with a BMI gain exceeding more than 1 kg/m2. The mean increase in BMI was 1,6 kg/m2 (minimum 0-maximum 3,9). None of the patients lost weight.Results Depending on the desired amount of breast augmentation the patients underwent between one to four operations. An average of 176 ml fat was transplanted per breast and surgery. In the first group a mean volume survival of 74 % (IQR 58 %-92 %) was observed. In the second group an increase of 135 % (IQR 105 %-318 %) of the volume of transplanted fat was observed. After an intermediate weight loss one of the patients regained her initial weight.Conclusion In this study the transplantation of autologous fat renders good long-term results. There is a significant correlation between change of weight and fat transplant volume survival over the years. This also explains the very high increase in breast volume in some patients. Autologous fat transplantation seems to be a safe and efficient method for breast augmentation. For further statements studies with larger number of cases are necessary.

Quantification of Nasal Septal Deviation With Computed Tomography Data.

Despite extensive literature on the classification and management of nasal septal deviation (NSD) for preoperative planning, standardized objective measures to evaluate the NSD severity remains challenging. In this study, we quantitatively analyzed NSD to determine the most predictive two-dimensional (2D) computed tomography (CT)-landmark for overall three-dimensional (3D) septal morphology derived from nasal airway segmentation. A retrospective study was conducted at a large academic center. One hundred four patients who underwent CT scans of the face were selected from a computer imaging database. Demographic variables were screened to ensure an equal number of men and women in different age groups. Digital Imaging and Communications in Medicine files were imported for 3D nasal cavity segmentation using 3D Slicer software. A volumetric analysis was performed to determine 3D NSD ratios. These values were compared to previously reported methods of obtaining objective 2D NSD measures using OsiriX and MATLAB software. Maximum deviation values were calculated using OsiriX, while the root mean square values were retrieved using MATLAB. Deviation area and curve to line ratios were both quantified using OsiriX and MATLAB. The data set consisted of 52 men and 52 women patients aged 20 to 100 years (mean = 58 years, standard deviation = 23 years). There was a strong correlation between 3D NSD ratio and maximum deviation (r = 0.789, P < 0.001) and deviation area (r = 0.775, P < 0.001). Deviation area (r = 0.563, P < 0.001), root mean square (r = 0.594, P < 0.001), and curve to line ratio (r = 0.470, P < 0.001) had a positive correlation of moderate strength. The curve to line ratio was not significant (r = 0.019, P = 0.85). The 2D CT-based NSD landmarks maximum deviation and deviation area were the most predictive of the severity of NSD from 3D nasal cavity segmentation. We present a robust open-source method that may be useful in predicting the severity of NSD in CT images.

Predicting the Ideal Ventricular Freehand Pass Trajectory Using Osirix Software and the Role of Occipital Shape Variations

Cannulation of lateral ventricles via a posterior approach is a common neurosurgical procedure. It is often believed that a single entry and fiducial point applies to all. No importance is given to skull shape variations, which can lead to wrong shunt positions and revisions. A virtual-reality study was conducted to find the ideal entry point, ideal forehead fiducial point, and ideal angulation of the ventricular catheter and variations in these with changes in skull shapes. Fifty human cadaveric skulls were used to measure anteroposterior (AP) diameter and width and to classify shape of skulls into 4 types. Hydrocephalus (100 cases) and normal magnetic resonance images (50 cases) were studied from a PACS (Picture Archiving and Communication System) database. An Osirix DICOM Viewer (3.9.4) was used to reconstruct the images and estimate the ideal, 90°, and midline shunt trajectory and correlate the same with AP/width ratios and skull shapes. Contrary to popular practice, the vertical distance from the inion for ideal trajectory placement was <6 cm and >4 cm in all shapes and ratio groups for hydrocephalus and nonhydrocephalus cases, respectively. As the AP/width ratio increases, the fiducial needs to be placed at a higher distance from the nasion and the distance of the entry point also increased from the inion. A rounder or more dolichocephalic skull dictates a 90° approach to be better, especially as the first pass. No magical external entry point uniformly applicable for all cases exists. Hence, there is a need to classify skulls according to shapes/ratios and to use a tailored approach for a freehand pass to cannulate the ventricles.

MRI perfusion analysis using freeware, standard imaging software

BackgroundPerfusion-weighted imaging is only scarcely used in veterinary medicine. The exact reasons are unclear. One reason might be the typically high costs of the software packages for image analysis. In addition, a great variability concerning available programs makes it hard to compare results between different studies. Moreover, these algorithms are tuned for their usage in human medicine and often difficult to adapt to veterinary studies.In order to address these issues, our aim is to deliver a free open source package for calculating quantitative perfusion parameters. We develop an “R package” calculating mean transit time, cerebral blood flow and cerebral blood volume from data obtained with freely imaging software (OsiriX Light®). We hope that the free availability, in combination with the fact that the underlying algorithm is open and adaptable, makes it easier for scientists in veterinary medicine to use, compare and adapt perfusion-weighted imaging analysis.In order to demonstrate the usage of our software package, we reviewed previously acquired perfusion-weighted images from a group of eight purpose-breed healthy beagle dogs and twelve client-owned dogs with idiopathic epilepsy. In order to obtain the data needed for our algorithm, the following steps were performed: First, regions of interest (ROI) were drawn around different, previously reported, brain regions and the middle cerebral artery. Second, a ROI enhancement curve was generated for each ROI using a freely available PlugIn. Third, the signal intensity curves were exported as a comma-separated-value file. These files constitute the input to our software package, which then calculates the PWI parameters.ResultsWe used our software package to re-assess perfusion weighted images from two previous studies. The clinical results were similar, showing a significant increase in the mean transit time and a significant decrease in cerebral blood flow for diseased dogs.ConclusionWe provide an “R package” for computing the main perfusion parameters from measurements taken with standard imaging software and describe in detail how to obtain these measurements. We hope that our contribution enables users in veterinary medicine to easily obtain perfusion parameters using standard Open Source software in a standard, adaptable and comparable way.

Video-based augmented reality combining CT-scan and instrument position data to microscope view in middle ear surgery

The aim of the study was to develop and assess the performance of a video-based augmented reality system, combining preoperative computed tomography (CT) and real-time microscopic video, as the first crucial step to keyhole middle ear procedures through a tympanic membrane puncture. Six different artificial human temporal bones were included in this prospective study. Six stainless steel fiducial markers were glued on the periphery of the eardrum, and a high-resolution CT-scan of the temporal bone was obtained. Virtual endoscopy of the middle ear based on this CT-scan was conducted on Osirix software. Virtual endoscopy image was registered to the microscope-based video of the intact tympanic membrane based on fiducial markers and a homography transformation was applied during microscope movements. These movements were tracked using Speeded-Up Robust Features (SURF) method. Simultaneously, a micro-surgical instrument was identified and tracked using a Kalman filter. The 3D position of the instrument was extracted by solving a three-point perspective framework. For evaluation, the instrument was introduced through the tympanic membrane and ink droplets were injected on three middle ear structures. An average initial registration accuracy of 0.21 ± 0.10 mm (n = 3) was achieved with a slow propagation error during tracking (0.04 ± 0.07 mm). The estimated surgical instrument tip position error was 0.33 ± 0.22 mm. The target structures’ localization accuracy was 0.52 ± 0.15 mm. The submillimetric accuracy of our system without tracker is compatible with ear surgery.

MRI study on the normal fetal development of cervical, thoracic and lumbar spines in specimens

Objective To assess the change rules of fetal cervical, thoracic and lumbar spinal volume and centrum volume with gestational ages. Methods The 3.0 T MRI was performed on 55 fetal specimens ranging from 17 to 42 gestational weeks with sequence of three dimensional T2WI. Among 55 samples, 20 samples were obtained from spontaneous abortion of pregnant women and 35 samples were obtained from induced labor of mothers due to serious diseases. The fetal specimen was derived from sectional imaging anatomy research institute of the medical school of Shandong University. No spinal abnormalities were found on CT scans. The cervical, thoracic and lumbar spinal volume was obtained by delineating the vertebral body contour on the reconstructed cross-sectional image with the OsiriX software (www.osirix-viewer.com). And the volume of the cervical, thoracic and lumbar spine was divided by the number of the vertebral bodies to obtain the centrum unit volume. Five lumbar vertebral bodies were measured one by one. Regression analysis was made between the volume of cervical, thoracic and lumbar spine and gestational weeks, and between the volume of lumbar vertebral bodies and gestational weeks to analyze the growth rule of spine. Results (1) The cervical, thoracic and lumbar spine volume increased linearly with gestational ages, and the linear regression equation was as follows: cervical spine volume (mm3) =-1 260.937+81.235×gestational week (R2=0.974, P<0.05), thoracic spine volume (mm3) =-5 933.521+347.503×gestational week (R2=0.972,P<0.05), lumbar spine volume (mm3) =-5 130.912+294.473×gestational week (R2=0.976,P<0.05). (2) The order from large to small of fetal spinal growth rate was thoracic, lumbar and cervical segment. Within the same gestational age, the order from large to small of spinal volume was thoracic, lumbar and cervical segment. The order from large to small of centrum unit volume growth rate was lumbar, thoracic and cervical vertebrae. (3) The volume of each lumbar vertebral body also increased linearly with gestational age. Conclusion The cervical, thoracic and lumbar volume show a good correlation with the gestational weeks in the second and third trimester fatal specimens, and the growth rate of different segments is different. Key words: Fetus; Spine; Bone development; Magnetic resonance imaging