Volumetric Comparison Research Articles

Volumetric comparison of maxillofacial soft tissue morphology: computed tomography in the supine position versus three-dimensional optical scanning in the sitting position

Three-dimensional (3-D) surgical simulation has become popular, but the accuracy of such simulation is difficult to assess. Because maxillofacial soft tissue profiles vary with posture, we compared such profiles obtained in the supine and sitting positions. In total, 28 patients with skeletal Class III jaw deformities underwent computed tomography in the supine position and 3-D optical scanning in the sitting position. The 2 sets of 3-D data were superimposed, and linear and volumetric differences were calculated. We evaluated the cheeks, the subauricular and infraorbital regions, the nose, the lips, and the chin. Statistical analyses were performed by using paired Student's t tests. Differences with P < .05 were considered significant. Patients were divided into 3 groups based on body mass index. The facial profiles of the cheeks and subauricular areas differed significantly between the sitting and supine positions. The extent of variation increased with body mass index. When a patient moves from the sitting position to the supine position, maxillofacial soft tissue migrates from the cheeks to the subauricular regions. Thus, simulations for surgery based on supine computed tomography alone do not accurately model the cheeks and subauricular areas.

Morphometric and volumetric comparison of 102 children with symptomatic and asymptomatic Chiari malformation Type I.

OBJECTIVE Chiari malformation Type I (CM-I) is typically defined on imaging by a cerebellar tonsil position ≥ 5 mm below the foramen magnum. Low cerebellar tonsil position is a frequent incidental finding on brain or cervical spine imaging, even in asymptomatic individuals. Nonspecific symptoms (e.g., headache and neck pain) are common in those with low tonsil position as well as in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and nonspecific symptoms. Because cerebellar tonsil position is not strictly correlated with the presence of typical CM-I symptoms, the authors sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish between patients with asymptomatic and symptomatic CM-I. METHODS The authors retrospectively analyzed records of 102 pediatric patients whose records were in the University of Michigan clinical CM-I database. All patients in this database had cerebellar tonsil position ≥ 5 mm below the foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. National Institutes of Health ImageJ software was used to obtain six 2D anatomical MRI measurements, and a semiautomated segmentation tool was used to obtain four 3D volumetric measurements of the posterior fossa and CSF subvolumes on MRI. RESULTS No significant differences were observed between patients with symptomatic and asymptomatic CM-I related to tentorium length (50.3 vs 51.0 mm; p = 0.537), supraoccipital length (39.4 vs 42.6 mm; p = 0.055), clivus-tentorium distance (52.0 vs 52.1 mm; p = 0.964), clivus-torcula distance (81.5 vs 83.3 mm; p = 0.257), total posterior fossa volume (PFV; 183.4 vs 190.6 ml; p = 0.250), caudal PFV (152.5 vs 159.8 ml; p = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs 0.0136; p = 0.649), or CSF volume to caudal PFV ratio (0.071 vs 0.061; p = 0.138). CONCLUSIONS No clinically useful 2D or 3D measurements were identified that could reliably distinguish pediatric patients with symptoms attributable to CM-I from those with asymptomatic CM-I.

A Subset of Dogs with Presumptive Idiopathic Epilepsy Show Hippocampal Asymmetry: A Volumetric Comparison with Non-Epileptic Dogs Using MRI.

MRI-acquired volumetric measurements from 100 dogs with presumptive idiopathic epilepsy (IE) and 41 non-epileptic (non-IE) dogs were used to determine if hippocampal asymmetry exists in the IE as compared to the non-IE dogs. MRI databases from three institutions were searched for dogs that underwent MRI of the brain and were determined to have IE and those that were considered non-IE dogs. Volumes of the right and left hippocampi were measured using Mimics® software. Median hippocampal volumes of IE and non-IE dogs were 0.47 and 0.53 cm3, respectively. There was no significant difference in overall hippocampal volume between IE and non-IE dogs; however, IE dogs had greater hippocampal asymmetry than non-IE dogs (P < 0.012). A threshold value of 1.16 from the hippocampal ratio had an 85% specificity for identifying IE-associated asymmetry. Thirty five percent of IE dogs had a hippocampal ratio >1.16. Asymmetry was not associated with any particular hemisphere (P = 0.67). Our study indicates that hippocampal asymmetry occurs in a subset of dogs with presumptive idiopathic/genetic epilepsy, suggesting a structural etiology to some cases of IE.

Diffusion tensor magnetic resonance imaging driven growth modeling for radiotherapy target definition in glioblastoma

Background: The clinical target volume (CTV) in radiotherapy is routinely based on gadolinium contrast enhanced T1 weighted (T1w + Gd) and T2 weighted fluid attenuated inversion recovery (T2w FLAIR) magnetic resonance imaging (MRI) sequences which have been shown to over- or underestimate the microscopic tumor cell spread. Gliomas favor spread along the white matter fiber tracts. Tumor growth models incorporating the MRI diffusion tensors (DTI) allow to account more consistently for the glioma growth. The aim of the study was to investigate the potential of a DTI driven growth model to improve target definition in glioblastoma (GBM).Material and methods: Eleven GBM patients were scanned using T1w, T2w FLAIR, T1w + Gd and DTI. The brain was segmented into white matter, gray matter and cerebrospinal fluid. The Fisher–Kolmogorov growth model was used assuming uniform proliferation and a difference in white and gray matter diffusion of a ratio of 10. The tensor directionality was tested using an anisotropy weighting parameter set to zero (γ0) and twenty (γ20). The volumetric comparison was performed using Hausdorff distance, Dice similarity coefficient (DSC) and surface area.Results: The median of the standard CTV (CTVstandard) was 180 cm3. The median surface area of CTVstandard was 211 cm2. The median surface area of respective CTVγ0 and CTVγ20 significantly increased to 338 and 376 cm2, respectively. The Hausdorff distance was greater than zero and significantly increased for both CTVγ0 and CTVγ20 with respective median of 18.7 and 25.2 mm. The DSC for both CTVγ0 and CTVγ20 were significantly below one with respective median of 0.74 and 0.72, which means that 74 and 72% of CTVstandard were included in CTVγ0 and CTVγ20, respectively.Conclusions: DTI driven growth models result in CTVs with a significantly increased surface area, a significantly increased Hausdorff distance and decreased overlap between the standard and model derived volume.

313 Morphometric and Volumetric Comparison of Symptomatic and Asymptomatic Chiari Malformation Type I

Abstract INTRODUCTION Chiari malformation type I (CMI) is typically defined by a cerebellar tonsil position 5 mm or more below foramen magnum. Low cerebellar tonsil position is a frequent incidental finding, even in asymptomatic individuals. Non-specific symptoms such as headache and neck pain are common in those with low tonsil position and in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and non-specific symptoms. Since cerebellar tonsil position is not strictly correlated with typical CMI symptoms, we sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish asymptomatic from symptomatic CMI patients. METHODS We retrospectively analyzed 102 pediatric patients from the University of Michigan clinical CMI database. All patients in this database have cerebellar tonsil position at least 5 mm below foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. Five 2D anatomic MRI measurements and four 3D volumetric measurements of posterior fossa and CSF sub-volumes on MRI were measured. RESULTS &gt;There were no significant differences observed between symptomatic and asymptomatic CMI patients related to basilar impression (−5.9 mm vs. −7.0 mm; P = 0.026), tentorium length (50.3 mm vs. 51.0 mm; P = 0.537), supraoccipital length (39.4 mm vs. 42.6 mm; P = 0.055), clivus-tentorium distance (52.0 mm vs. 52.1 mm; P = 0.964), clivus-torcula distance (81.5 mm vs. 83.3 mm; P = 0.257), total posterior fossa volume (PFV; 183.4 mL vs. 190.6 mL; P = 0.250), caudal PFV (152.5 mL vs. 159.8 mL; P = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs. 0.0136; P = 0.649), or CSF volume to caudal PFV ratio (0.071 vs. 0.061; P = 0.138). CONCLUSION We did not identify any 2D or 3D measurements that could reliably distinguish pediatric patients with symptoms attributable to CMI from those with asymptomatic CMI.

Neural correlates of visual memory in patients with diffuse axonal injury

ABSTRACTPrimary objective: To investigate the neural substrates of visual memory in a sample of patients with traumatic brain injury (TBI). We hypothesized that patients with decreased grey and white matter volume in frontal and parietal cortices as well as medial temporal and occipital lobes would perform poorly on the tests of visual memory analysed.Methods and procedures: 39 patients and 53 controls were assessed on tests of visual memory and learning from the Cambridge Neuropsychological Test Automated Battery (CANTAB). Patients with TBI were scanned with magnetic resonance imaging (MRI). Partial correlations and multiple regression analyses were used to examine relationships between cognitive variables and MRI volumetric findings. This study complements and extends previous studies by performing volumetric comparisons on a variety of resolution levels, from whole brain to voxel-based level analysis.Main outcomes and results: Patients with TBI performed significantly worse than controls in all the tasks assessed. Performance was associated with wide-spread reductions in grey and white matter volume of several cortical and subcortical structures as well as with cerebrospinal fluid space enlargement in accordance with previous studies of memory in patients with TBI and cognitive models suggesting that memory problems involve the alteration of multiple systems.Conclusions: Our results propose that compromised visual memory in patients with TBI is related to a distributed pattern of volume loss in regions mediating memory and attentional processing.

OC-0268: Volumetric comparison between PET/CT and CT simulation for target delineation in esophageal cancer

OC-0268: Volumetric comparison between PET/CT and CT simulation for target delineation in esophageal cancer

Three-dimensional surgical modelling with an open-source software protocol: study of precision and reproducibility in mandibular reconstruction with the fibula free flap

Very few surgical teams currently use totally independent and free solutions to perform three-dimensional (3D) surgical modelling for osseous free flaps in reconstructive surgery. This study assessed the precision and technical reproducibility of a 3D surgical modelling protocol using free open-source software in mandibular reconstruction with fibula free flaps and surgical guides. Precision was assessed through comparisons of the 3D surgical guide to the sterilized 3D-printed guide, determining accuracy to the millimetre level. Reproducibility was assessed in three surgical cases by volumetric comparison to the millimetre level. For the 3D surgical modelling, a difference of less than 0.1mm was observed. Almost no deformations (<0.2mm) were observed post-autoclave sterilization of the 3D-printed surgical guides. In the three surgical cases, the average precision of fibula free flap modelling was between 0.1mm and 0.4mm, and the average precision of the complete reconstructed mandible was less than 1mm. The open-source software protocol demonstrated high accuracy without complications. However, the precision of the surgical case depends on the surgeon’s 3D surgical modelling. Therefore, surgeons need training on the use of this protocol before applying it to surgical cases; this constitutes a limitation. Further studies should address the transfer of expertise.

Objective Quantification of Trochlea Dysplasia: Assessment of Morphology Difference Between Control and Chronic Patellofemoral Instability Patients

Aims and Objectives:Trochlear dysplasia is an important risk factor associated with patellofemoral instability, but it remains difficult to classify with consistency. Currently there is no objective way to quantify the dysplasia. The purpose of this study to define and quantify objectively the trochlea morphology by volume and length via computed tomography (CT). Hypothesis: A significant difference in trochlea groove volume and length is present within a cohort of patients with recurrent patellofemoral instability if compared to a control cohort of similar patients.Materials and Methods:One-hundred control patients (136 knees) were retrospectively reviewed and compared to 36 consecutive patients (72 knees) who were treated surgically for recurrent patella instability and known trochlea dysplasia based on a lateral x-ray. Trochlea morphology was analyzed from a pre-operative CT and data presented as trochlear sulcus volume trochlea length. To determine where along the trochlea length dysplasia is most variable, the trochlea length was radiographically divided into thirds, volume was quantified along that section and compared to control trochlea.Results:A significant difference in trochlea morphology exists between cohorts, volume (1.98 vs 3.77 cm3) and length (31.97 vs 34.66 mm). However, there appears to be a gender based difference in trochlea morphology. The trochlea volumetric analysis between the female cohorts (L: 2.02 cm3 vs. 2.94 cm3, R: 1.95 cm3 vs. 2.93 cm3) demonstrated significant less volume in instability patients (p<0.001). The proximal 30% of trochlea contributed the majority of dysplasia difference determined by comparing mean trochlea volume, 95% of the difference. This difference decreased in distal sections, 53% and 32% respectively. The total trochlea length did not appear to be significant (L: p=0.858, R: p=0.913). It appears dysplasia alone may not directly lead to symptoms demonstrated by trochlea volumetric comparisons within symptomatic recurrent patella instability and contralateral asymptomatic patella (p=0.274).Conclusion:The authors believe this reproducible technique can be used to quantify the trochlea morphology into measurements to be used describing the severity of the dysplasia. The data confirms that symptomatic trochlea dysplasia is a “proximal” process affecting early knee flexion contact between patella and trochlea.

Detection of Conversion from Mild Cognitive Impairment to Alzheimer's Disease Using Longitudinal Brain MRI.

Mild Cognitive Impairment (MCI) is an intermediate stage between healthy and Alzheimer's disease (AD). To enable early intervention it is important to identify the MCI subjects that will convert to AD in an early stage. In this paper, we provide a new method to distinguish between MCI patients that either convert to Alzheimer's Disease (MCIc) or remain stable (MCIs), using only longitudinal T1-weighted MRI. Currently, most longitudinal studies focus on volumetric comparison of a few anatomical structures, thereby ignoring more detailed development inside and outside those structures. In this study we propose to exploit the anatomical development within the entire brain, as found by a non-rigid registration approach. Specifically, this anatomical development is represented by the Stationary Velocity Field (SVF) from registration between the baseline and follow-up images. To make the SVFs comparable among subjects, we use the parallel transport method to align them in a common space. The normalized SVF together with derived features are then used to distinguish between MCIc and MCIs subjects. This novel feature space is reduced using a Kernel Principal Component Analysis method, and a linear support vector machine is used as a classifier. Extensive comparative experiments are performed to inspect the influence of several aspects of our method on classification performance, specifically the feature choice, the smoothing parameter in the registration and the use of dimensionality reduction. The optimal result from a 10-fold cross-validation using 36 month follow-up data shows competitive results: accuracy 92%, sensitivity 95%, specificity 90%, and AUC 94%. Based on the same dataset, the proposed approach outperforms two alternative ones that either depends on the baseline image only, or uses longitudinal information from larger brain areas. Good results were also obtained when scans at 6, 12, or 24 months were used for training the classifier. Besides the classification power, the proposed method can quantitatively compare brain regions that have a significant difference in development between the MCIc and MCIs groups.

Three-Dimensional Analysis of Long-Term Stability After Bilateral Sagittal Split Ramus Osteotomy Fixed With a Single Miniplate With 4 Monocortical Screws and 1 Bicortical Screw: A Retrospective 2-Center Study

This study evaluated the long-term stability of bilateral sagittal split ramus osteotomy fixed with a single miniplate with 4 monocortical screws and 1 bicortical screw (hybrid technique [HT]) using 3-dimensional (3D) analysis and an objective measuring tool, cone-beam computed tomography (CBCT). Sixty-four patients who underwent bimaxillary surgery with mandibular advancement fixed with the HT were selected from 2 different institutions and enrolled in this retrospective study. All patients underwent CBCT preoperatively, 1month after surgery, and 12months after surgery. To estimate the long-term stability of the HT, volumetric comparisons were performed using the following measurements: distance between the gonion and the B point in the sagittal plane; distance between the right and left gonion transversally; and the angle of the line connecting the mandibular notch and the gonion and the line connecting the gonion and the B point vertically. Statistical analysis showed no relevant relapse (<1mm or <1°) when using the HT. However, a positive correlation between the amount of advancement and the amount of postoperative relapse was observed. The HT produces stable postoperative 3D results after 12months.

Occipitocervical Instability After Far-Lateral Transcondylar Surgery: A Biomechanical Analysis.

After a far-lateral transcondylar approach, patients may maintain neutral alignment in the immediate postoperative period, but severe occipitoatlantal subluxation may occur gradually with cranial settling and possible neurological injury. Previous research is based on assumptions regarding the extent of condylar resection and the change in biomechanics that produces instability. To quantify the extent of bone removal during a far-lateral transcondylar approach, determine the changes in range of motion (ROM) and stiffness that occur after condylar resection, and identify the threshold of condylar resection that predicts alterations in occipitocervical biomechanics. Nine human cadaveric specimens were biomechanically tested before and after far-lateral transcondylar resection extending into the hypoglossal canal (HC). The extent of condylar resection was quantified using volumetric comparison between pre- and postresection computed tomography scans. ROM and stiffness testing were performed in intact and resected states. The extent of resection that produced alterations in occipitocervical biomechanics was assessed with sensitivity analysis. Bone removal during condylar resection into the HC was 15.4%-63.7% (mean 35.7%). Sensitivity analysis demonstrated that changes in biomechanics may occur when just 29% of the occipital condyle was resected (area under the curve 0.80-1.00). Changes in occipitocervical biomechanics may be observed if one-third of the occipital condyle is resected. During surgery, the HC may not be a reliable landmark to guide the extent of resection. Patients who undergo condylar resections extending into or beyond the HC require close surveillance for occipitocervical instability.

Multitemporal Volume Registration for the Analysis of Rheumatoid Arthritis Evolution in the Wrist.

This paper describes a method based on an automatic segmentation process to coregister carpal bones of the same patient imaged at different time points. A rigid registration was chosen to avoid artificial bone deformations and to allow finding eventual differences in the bone shape due to erosion, disease regression, or other eventual pathological signs. The actual registration step is performed on the basis of principal inertial axes of each carpal bone volume, as estimated from the inertia matrix. In contrast to already published approaches, the proposed method suggests splitting the 3D rotation into successive rotations about one axis at a time (the so-called basic or elemental rotations). In such a way, singularity and ambiguity drawbacks affecting other classical methods, for instance, the Euler angles method, are addressed. The proposed method was quantitatively evaluated using a set of real magnetic resonance imaging (MRI) sequences acquired at two different times from healthy wrists and by choosing a direct volumetric comparison as a cost function. Both the segmentation and registration steps are not based on a priori models, and they are therefore able to obtain good results even in pathological cases, as proven by the visual evaluation of actual pathological cases.

The enduring legacy of pioneering neuroscientist Dr. Jerzy Edwin Rose

The human nervous system maintains dominion over everything experienced in life, consolidating a constant barrage of stimuli and chemical fluctuation into memory, sense, emotion, and even character. Despite decades of productive investigation, comprehension of the nervous system’s function and structure remain shrouded in mystery. Historically, the burden of elucidating these mysteries has fallen to neuroscientists bold enough to seek answers to this most nebulous vista. The legacy of one such neuroscientist, Jerzy Edwin Rose, endures today as a pillar of neuroscientific discovery. In the nascence of his career, Rose explored volumetric comparisons of human brain structure to that of other mammals, leading to the development of novel methods in neurophysiologic measurement and explanation. Rose would later segue mid-career into studies on the cooperation between the auditory cortex and thalamus, resulting in increased understanding of its functioning, structure, and anatomy. During the final saga of his long, fruitful career, Rose explored the electrophysiology of the auditory system, leading to novel methods using modern technology. Ultimately, the vast breadth of Rose’s contributions to neuroscience has diminished the field’s mystery, setting forth momentous groundwork for future discovery, and the inspiration to carry on in the spirit of his bold curiosity.

VOLUMETRIC COMPARISON OF AUTOMATICALLY SEGMENTED HIPPOCAMPAL SUBFIELDS FROM 4-MIN ACCELERATED VERSUS 8-MIN T2-WEIGHTED 3T MRI SCANS

VOLUMETRIC COMPARISON OF AUTOMATICALLY SEGMENTED HIPPOCAMPAL SUBFIELDS FROM 4-MIN ACCELERATED VERSUS 8-MIN T2-WEIGHTED 3T MRI SCANS

Volumetric and dosimetric comparison in adaptive radiotherapy for patients with head and neck cancer: a systematic review and Meta-analysis

Objective To perform a systematic review and Meta-analysis on volumetric and dosimetric changes in target volumes and organs at risk (OARs) in adaptive radiotherapy (ART) for patients with head and neck cancer (HNC), and to investigate the role of ART in the treatment of HNC. Methods Literature retrieval was performed to include related studies, and the parameters of primary tumor, GTV-T and GTV-N, parotid volume, D95 and Dmean of target volumes, Dmean of ipsilateral and contralateral parotid volume (I-PG and C-PG), and Dmax of the spinal cord and brainstem. Results A total of 17 studies involving 336 patients were included in the meta-analysis. Primary tumor and parotid volume changed significantly. The volumes of GTV-T, GTV-N, and I-PG were significantly reduced during the 15-20th radiotherapy and after the 20th radiotherapy (P<0.05), and the C-PG was significantly reduced after the 20th radiotherapy (P=0.004). The analysis of actual dose showed that the D95 and Dmean of primary tumor showed no significant differences, and during the 15-20th radiotherapy, the Dmax of the spinal cord was increased by 2.26 Gy (P=0.000), while the Dmax of the brainstem showed no significant changes before the 20th radiotherapy and was increased by 1.78 Gy after the 25th radiotherapy (P=0.020). In addition, the Dmean of I-PG was increased by 2 Gy during the 20-25th radiotherapy (P=0.0001), and the Dmean of C-PG was increased before the 20th radiotherapy and showed no significant changes after the 25th radiotherapy (P=0.110). The dosimetric analysis of ART showed that the Dmax of the spinal cord and brainstem was reduced significantly (spinal cord: MD=-2.15, 95% CI-3.12 to -1.18, P=0.000; brainstem: MD=-2.20, 95% CI-3.32 to -1.09, P=0.000). The Dmean of I-PG was reduced by about 3.5 Gy, and the sensitivity analysis revealed that the results of Dmean of C-PG were unstable. Conclusions The volumes of primary tumors and parotid glands change significantly, and the actual doses of OARs (Dmax of the spinal cord and brainstem and Dmean of the parotid glands) significantly increase, while the doses of GTV-T and GTV-N show no significant changes. ART can effectively protect the OARs, and patients with locally advanced HNC who receive concurrent chemoradiotherapy can obtain good dose gains from ART plan performed during the 15-20th radiotherapy and at about the 25th radiotherapy. Key words: Head and neck cancer; Adaptive radiotherapy; Volumetric and dosimetric comparison; Meta analysis

A Multimodal Structural and Functional Neuroimaging Study of Amnestic Mild Cognitive Impairment

Examination of brain structural and functional abnormalities in amnestic mild cognitive impairment (aMCI) has the potential to enhance our understanding of the initial pathophysiological changes in dementia. We examined gray matter volumes and white matter microstructural integrity, as well as resting state functional connectivity (rsFC) in patients with aMCI (N = 48) in comparison to elderly cognitively healthy comparison subjects (N = 48). Brain volumetric comparisons were carried out using voxel-based morphometric analysis of T1-weighted images using the FMRIB Software Library. White matter microstructural integrity was examined using whole-brain tract-based spatial statistics analysis of fractional anisotropy maps generated from diffusion tensor imaging data. Finally, rsFC differences between the samples were examined by Multivariate Exploratory Linear Optimised Decomposition into Independent Components of the resting state functional magnetic resonance imaging time series, followed by between-group comparisons of selected networks using dual regression analysis. Patients with aMCI showed significant gray matter volumetric reductions in bilateral parahippocampal gyri as well as multiple other brain regions including frontal, temporal, and parietal cortices. Additionally, reduced rsFC in the anterior subdivision of the default mode network (DMN) and increased rsFC in the executive network were noted in the absence of demonstrable impairment of white matter microstructural integrity. We conclude that the demonstrable neuroimaging findings in aMCI include significant gray matter volumetric reductions in the fronto-temporo-parietal structures as well as resting state functional connectivity disturbances in DMN and executive network. These findings differentiate aMCI from healthy aging and could constitute the earliest demonstrable neuroimaging findings of incipient dementia.

Volumetric and dosimetric comparison of computerised radiotherapy treatment plan between using positron emission tomography/computed tomography (PET/CT) and CT images for target delineation in non-small cell lung cancer patients

AbstractPurposeTo compare intensity-modulated radiation therapy (IMRT) treatment planning between using positron emission tomography/computed tomography (PET/CT) and CT for target volume delineation in patients with non-small cell lung cancer (NSCLC).MethodsNine NSCLC patients with PET/CT images were enrolled into this study. Gross tumour volumes (GTVs) were delineated by the PET visual assessment (PETvis), the automated PET (PETauto), standardised uptake value (SUV)&gt;2·5 (PET2·5) and threshold 40% SUVmax (PET40), and CT-based method. For each patient, two IMRT treatment plans based on CT and PET/CT delineation were performed. The target coverage and the dose–volume parameters for organs at risk were analysed.ResultsThe PETauto referred to PET40 when SUVmax&lt;7 and PET2·5 when SUVmax≥7. The mean GTVs were 15·04, 15·7 and 15·14 cc for PETauto, PETvis and CT based, respectively. The GTV of PETauto was not different from PETvis (p=0·441) and CT based (p=0·594). Based on CT delineation in IMRT planning, only 34% of the cases had sufficient PET/CT planning target volumes coverage, whereas the organs at risk dose parameters were not statistically significant (p&gt;0·05).ConclusionsPET/CT enables more accurate assessment of tumour delineation for NSCLC, therefore improve target coverage in IMRT plan.

Outcomes and Durability of Hepatic Reduction after Combined Partial Hepatectomy and Cyst Fenestration for Massive Polycystic Liver Disease

Partial hepatectomy and cyst fenestration (PHCF) selectively provides clinical benefit in highlysymptomatic patients with polycystic liver disease (PLD). This study aims to ascertain whether the reduction in liver volume (LV) achieved by PHCF is sustained long term. Clinical data were retrieved from the electronic records of all patients with PLD who underwent PHCF between 1985 and 2014. Preoperative LVs (LV1), postoperative LVs (LV2), and late follow-up LVs (LV3) were measured from magnetic resonance or CT images. Among 186 patients who underwent PHCF, 91% were Caucasian women with autosomal dominant polycystic kidney disease with a mean age of 49 years. Major perioperative complications (Clavien III/IV) occurred in 21% of the patients. Operative mortality (<90 days) was 2.7%. Eleven patients had liver failure develop, received liver transplants, or had liver-related deaths. Overall survival was 95.7%, 93.3%, 85.6%, and 77.7% at 1, 5, 10, and 15 years respectively. Imaging records for volumetry were unavailable in 32 patients. Of the remaining 154 patients, 34 had imaging for 1 LV, 64 for 2 LVs, and 55 for all 3 LVs. Median LV was 6,781 mL (interquartile range 4,903 to 8,341 mL) preoperatively and 2,502 mL (interquartile range 2,089 to 3,136 mL) after PHCF, leading to a median postoperative LV reduction of 61%. At follow-up (mean 8 years), median LV was 2,519 mL (interquartile range 2,083 to 3,752 mL). Interestingly, 33 of 62 patients with available LV2 and LV3 showed additional regression in LV at follow-up (median-14.1%), and the rest showed mild growth of 9.9%. Overall volumetric comparison of preoperative with follow-up liver imaging showed sustained LV reduction (median 61%). Sustained long-term reductions in LV after PHCF can be achieved in selected patients with severe, highly symptomatic PLD. In our experience, liver-related death and subsequent liver transplantation are infrequent after PHCF.

Human identification through frontal sinus 3D superimposition: Pilot study with Cone Beam Computer Tomography

As a unique anatomical feature of the human body, the frontal sinus morphology has been used for identification of unknown bodies with many techniques, mostly using 2D postero-anterior X-rays. With the increase of the use of Cone-Beam Computer Tomography (CBCT), the availability of this exam as ante-mortem records should be considered. The purpose of this study is to establish a new technique for frontal sinus identification through direct superimposition of 3D volumetric models obtained from CBCT exam, by testing two distinct situations. First, a reproducibility test, where two observers independently rendered models of frontal sinus from a sample 20 CBCT exams and identified them on each other's list. In the second situation, one observer tested the protocol and established on different exams of three individual. Using the open source DICOM viewer InVesallius® for rendering, Mesh Lab®, for positioning the models and CloudCompare for volumetric comparison, both observers matched cases with 100% accuracy and the level of coincidence in a identification situation. The uniqueness of the frontal sinus topography is remarkable and through the described technique, can be used in forensic as an identification method whenever both the sinus structure and antemortem computer tomography is available.