The benefit of stereology for quantitative radiology

Perinatal exposure to the immune-suppressant di-n-octyltin dichloride affects brain development in rats

Disruption of the immune system during embryonic brain development by environmental chemicals was proposed as a possible cause of neurodevelopmental disorders. We previously found adverse effects of di-n-octyltin dichloride (DOTC) on maternal and developing immune systems of rats in an extended one-generation reproductive toxicity study according to the OECD 443 test guideline. We hypothesize that the DOTC-induced changes in the immune system can affect neurodevelopment. Therefore, we used in-vivo MRI and PET imaging and genomics, in addition to behavioral testing and neuropathology as proposed in OECD test guideline 443, to investigate the effect of DOTC on structural and functional brain development. Male rats were exposed to DOTC (0, 3, 10, or 30 mg/kg of diet) from 2 weeks prior to mating of the F0-generation until sacrifice of F1-animals. The brains of rats, exposed to DOTC showed a transiently enlarged volume of specific brain regions (MRI), altered specific gravity, and transient hyper-metabolism ([18F]FDG PET). The alterations in brain development concurred with hyper-responsiveness in auditory startle response and slight hyperactivity in young adult animals. Genomics identified altered transcription of key regulators involved in neurodevelopment and neural function (e.g. Nrgrn, Shank3, Igf1r, Cck, Apba2, Foxp2); and regulators involved in cell size, cell proliferation, and organ development, especially immune system development and functioning (e.g. LOC679869, Itga11, Arhgap5, Cd47, Dlg1, Gas6, Cml5, Mef2c). The results suggest the involvement of immunotoxicity in the impairment of the nervous system by DOTC and support the hypothesis of a close connection between the immune and nervous systems in brain development.

Measurement of changes in uterine and fibroid volume during treatment of heavy menstrual bleeding (HMB)

STUDY QUESTION

Does application of an unbiased method for analysis of magnetic resonance (MR) images reveal any effect on uterine or fibroid volume from treatment of heavy menstrual bleeding (HMB) with three 12-week courses of the selective progesterone receptor modulator ulipristal acetate (SPRM-UPA)?

SUMMARY ANSWER

Application of an unbiased method for analysis of MR images showed that treatment of HMB with SPRM-UPA was not associated with a significant reduction in the volume of the uterus or in the volume of uterine fibroids.

WHAT IS KNOWN ALREADY

SPRM-UPA shows therapeutic efficacy for treating HMB. However, the mechanism of action (MoA) is not well understood and there have been mixed reports, using potentially biased methodology, regarding whether SPRM-UPA has an effect on the volume of the uterus and fibroids.

STUDY DESIGN SIZE DURATION

In a prospective clinical study (with no comparator), 19 women with HMB were treated over a period of 12 months with SPRM-UPA and uterine and fibroid size were assessed with high resolution structural MRI and stereology.

PARTICIPANTS/MATERIALS SETTING METHODS

A cohort of 19 women aged 38-52 years (8 with and 11 without fibroids) were treated with three 12-week courses of 5 mg SPRM-UPA given daily, with four weeks off medication in-between treatment courses. Unbiased estimates of the volume of uterus and total volume of fibroids were obtained at baseline, and after 6 and 12 months of treatment, by using the Cavalieri method of modern design-based stereology in combination with magnetic resonance imaging (MRI).

MAIN RESULTS AND THE ROLE OF CHANCE

Bland-Altman plots showed good intra-rater repeatability and good inter-rater reproducibility for measurement of the volume of both fibroids and the uterus. For the total patient cohort, two-way ANOVA did not show a significant reduction in the volume of the uterus after two or three treatment courses of SPRM-UPA (P = 0.51), which was also the case when the groups of women with and without fibroids were considered separately (P = 0.63). One-way ANOVA did not show a significant reduction in total fibroid volume in the eight patients with fibroids (P = 0.17).

LIMITATIONS REASONS FOR CAUTION

The study has been performed in a relatively small cohort of women and simulations that have subsequently been performed using the acquired data have shown that for three time points and a group size of up to 50, with alpha (Type I Error) and beta (Type II Error) set to 95% significance and 80% power, respectively, at least 35 patients would need to be recruited in order for the null hypothesis (that there is no significant reduction in total fibroid volume) to be potentially rejected.

WIDER IMPLICATIONS OF THE FINDINGS

The imaging protocol that we have developed represents a generic paradigm for measuring the volume of the uterus and uterine fibroids that can be readily incorporated in future studies of medical treatments of HMB. In the present study, SPRM-UPA failed to produce a significant reduction in the volume of the uterus or the total volume of fibroids (which were present in approximately half of the patients) after either two or three 12-week courses of treatment. This finding represents a new insight in respect of the management of HMB using treatment strategies that target hormone-dependence.

STUDY FUNDING/COMPETING INTERESTS

The UPA Versus Conventional Management of HMB (UCON) trial was funded by the EME Programme (Medical Research Council (MRC) and National Institutes of Health Research (NIHR)) (12/206/52). The views expressed in this publication are those of the authors and not necessarily those of the Medical Research Council, National Institute for Health Research, or Department of Health and Social Care.Medical Research Council (MRC) Centre grants to the Centre for Reproductive Health (CRH) (G1002033 and MR/N022556/1) are also gratefully acknowledged. H.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (All paid to Institution) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc., and Myovant Sciences GmbH. H.C. has received royalties from UpToDate for an article on abnormal uterine bleeding. L.W. has received grant funding from Roche Diagnostics (Paid to Institution). All other authors have no conflicts to declare.

TRIAL REGISTRATION NUMBER

The study reported here is an embedded mechanism of action study (no comparator) within the UCON clinical trial (registration ISRCTN: 20426843).

Microscopic anatomy of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) a histochemical, stereological, and scanning electron microscope study

The present work was designed to investigate the microscopic structure of the oesophagus in the southern white-breasted hedgehog (Erinaceus concolor) using histochemical staining, Scanning electron microscope (SEM), and stereological procedures. Four adult males were included in our study. Serial sections of the entire length of the oesophagus were stained with aldehyde fuchsin, alcian blue (pH 2.5), Periodic acid Schiff (PAS), and Masson's trichrome. Then, the total volume of the oesophagus, and the total volume of its different layers, were estimated using Cavalieri's principle. The oesophageal epithelium was a non-keratinized stratified squamous type. Muscularis mucosa was present as a thick layer between lamina propria and submucosa and its thickness was increased toward the stomach. Tunica submucosa was a loose connective tissue containing an oesophageal gland with PAS-positive and AB-positive reactions throughout the submucosa and become denser toward the stomach. The tunica muscularis consisted of two distinct striated muscle layers, and its thickness was decreased toward the stomach. On SEM images, the cervical and thoracic oesophagus showed shallow folding, while the abdominal part had deeper folds. The present findings indicate that the histological properties of the oesophagus in southern white-breasted hedgehogs have slight similarities with rodents and considering its epithelium, submucosal glands and tunica muscularis more resemble with dog oesophagus. The obtained results may be quite helpful to improve the current knowledge of the histophysiology of the hedgehog gastrointestinal tract as a member of eulipotyplan mammals and as a pet for biologists and veterinarians.

Applications of various stereological tools for estimation of biological tissues

To provide concise and brief important stereological application methods and techniques for estimating biological tissues. Stereology studies the quantity of biological tissue using little practice and the low price of counting and preparing tissue slices to obtain direct and accurate results. Since their establishment, the stereological techniques underwent much improvement, thus allowing more precise analysis of target structures using various approaches. Using stereological tools, advances in stereological techniques made the target tissues or organs represented by 2D instead of 3D dimensions. Process tools estimate volume, area and length. According to the exciting tissue and aims, the stereological tools perform differently. This review summarizes various stereological tools and techniques, providing brief information about the orientation method, slicer probe method, Delesse's principle, Cavalieri principle, disector, fractionator, nucleator, virtual cycloids and saucer, which are described in detail.

A new supportive approach in the diagnosis of Chiari malformation type 1 in pediatric patients

PURPOSE

Chiari malformation type 1 (CM-1) is a posterior fossa anomaly characterized by herniation of the cerebellar tonsils from the foramen magnum (FM). This study compares FM, medulla spinalis (MS), and herniated cerebellar tonsils ratios by making area measurements from axial plane MRI in CM-1 patients and the control group.

METHODS

Our study evaluated 30 pediatric patients with CM-1 and 30 people in the control group. The lengths of the McRae line, twining line, and clivus line were measured on the posterior cranial fossa evaluation. The areas of FM (A_FM), MS (A_MS), and herniated cerebellar tonsils (A_TONSILS) were measured by axial images.

RESULTS

As a result of area measurements obtained from axial cross-sectional MRI, a statistically significant difference was found between CM-1 patients and the control group. According to the results of the ROC analysis, if an individual's A_MS/A_FM value is above 17.9% or the A_TONSILS/A_FM value is above 18.4%, it can be interpreted as a CM-1 patient.

CONCLUSION

It will be easier to diagnose the patient with the new approach we obtained from axial MR images in addition to sagittal MR images. This method can be a guide in some cases when the surgeons are undecided.

Estimation of Spleen Volume Using MRI Segmentation: Would One Slice Be Enough?

This study aimed to establish spleen volume in adult Sudanese using manual segmentation and the Cavalieri method with magnetic resonance images (MRI). A total of 345 abdominal MRI scans for adults were retrospectively studied for patients who underwent abdomen MRI between September to October 2016. The data were collected from two scanning centers in Khartoum, Sudan. For each series of sectional images, the spleen was manually segmented, and the volume was calculated using matrix laboratory (MATLAB) code. Furthermore, abdominal circumferences and diameters, in addition to L1 body dimension and spinal canal, were measured.  The mean splenic volume in our study was 187.2 cm³, without a significant change with age (P = 0.269). The average volume in males was 223.5 cm³ while in females it was 170.27 cm³. The average coefficient error (CE) was 0.029. A positive significant correlation was found between the volume and spleen length (beta standardized coefficient = 0.781, P < 0.05). The mean length was 9.18 cm. Additionally, our data showed an insignificant correlation between the volume and the other measurements, except for the abdomen transverse diameter (beta standardized coefficient = 0.267, P < 0.05).  The results of our study coincided with previous studies in the normal range of spleen volume and the strong correlation with length, regardless of the irregular shape of the spleen. In addition, manual segmentation was a reliable method to measure spleen volume objectively. However, our single-slice measurements were insufficient.

A Deep Learning Approach for Automated Segmentation of Kidneys and Exophytic Cysts in Individuals with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Total kidney volume (TKV) is an important imaging biomarker in autosomal dominant polycystic kidney disease (ADPKD). Manual computation of TKV, particularly with the exclusion of exophytic cysts, is laborious and time consuming.

METHODS

We developed a fully automated segmentation method for TKV using a deep learning network to selectively segment kidney regions while excluding exophytic cysts. We used abdominal T₂ -weighted magnetic resonance images from 210 individuals with ADPKD who were divided into two groups: one group of 157 to train the network and a second group of 53 to test it. With a 3D U-Net architecture using dataset fingerprints, the network was trained by K-fold cross-validation, in that 80% of 157 cases were for training and the remaining 20% were for validation. We used Dice similarity coefficient, intraclass correlation coefficient, and Bland-Altman analysis to assess the performance of the automated segmentation method compared with the manual method.

RESULTS

The automated and manual reference methods exhibited excellent geometric concordance (Dice similarity coefficient: mean±SD, 0.962±0.018) on the test datasets, with kidney volumes ranging from 178.9 to 2776.0 ml (mean±SD, 1058.5±706.8 ml) and exophytic cysts ranging from 113.4 to 2497.6 ml (mean±SD, 549.0±559.1 ml). The intraclass correlation coefficient was 0.9994 (95% confidence interval, 0.9991 to 0.9996; P<0.001) with a minimum bias of -2.424 ml (95% limits of agreement, -49.80 to 44.95).

CONCLUSIONS

We developed a fully automated segmentation method to measure TKV that excludes exophytic cysts and has an accuracy similar to that of a human expert. This technique may be useful in clinical studies that require automated computation of TKV to evaluate progression of ADPKD and response to treatment.

Predictive value of retinal nerve fibre layer thickness for postoperative visual improvement in patients with pituitary macroadenoma

Objective

To determine the usefulness of retinal nerve fibre layer (RNFL) thickness and a reliable cut-off value that can predict postoperative visual function improvement in patients with pituitary macroadenoma.

Methods and Analysis

This was a prospective observational study. Preoperative optical coherence tomography of the RNFL was performed in patients with pituitary macroadenoma. Postoperative visual function changes (acuity and visual fields) were identified using predefined criteria. Receiver operating characteristic curves were constructed for RNFL values to define the ideal cut-off value that predicted improvement. Other variables including preoperative visual acuity, mean deviation, visual field index and tumour volume were also analysed.

Results

Twenty-nine eligible subjects (58 eyes) were recruited. The mean (±SD) age was 43.9 (±12.85) years and 65.5% were male. The mean (±SE) follow-up duration was 20.8 (±6.42) months. RNFL thickness was significantly thinner in eyes with visual dysfunction and optic disc pallor. Better preoperative logarithmic minimum angle of resolution (logMAR) visual acuity, higher RNFL thickness and smaller tumour volume were associated with postoperative visual field improvement on univariate analysis; however, only mean RNFL thickness had significant association on multivariate analysis. None of the preoperative variables showed significant association with improvement in visual acuity. The best cut-off of mean RNFL thickness for visual field improvement was estimated at 81 μm with 73.1% sensitivity and 62.5% specificity.

Conclusion

Preoperative RNFL thickness can be an objective predictor of visual field outcomes in patients undergoing surgery for pituitary macroadenomas, with moderate sensitivity and specificity. It is, however, not a good predictor of visual acuity outcome.

CT anatomy of the head in the Ile de France sheep

Background

CT scan images provide accurate anatomical data from different areas of the body that can be used to diagnose diseases.

Objectives

The present work aimed to describe the normal anatomical structures of the Ile de France sheep head and its morphometric and volumetric properties using computed tomography (CT) and stereological methods.

Methods

Five adult Ile de France sheep heads, which were of mature age (above 10 months), were included in this study. The different cavities of the head, including the nasal cavity, paranasal sinuses, oral cavity, orbital cavity and vestibulocochlear system, were evaluated using CT scans, cross, sagittal and coronal sections.

Results

The mean length, height and width of the skull were 25.3 ± 1.02, 9.8 ± 0.93 and 12.3 ± 0.91 cm, respectively. The results showed that the nasal cavity is divided into three regions. Vestibular, respiratory and olfactory regions. The paranasal sinuses are composed of maxillary, frontal, palatine, sphenoid, lacrimal and ethmoidal that were identified and named in the CT scan images and their corresponding anatomical cross‐sections. The total volume of the head, nasal cavity and oral cavity was estimated to be 2998 ± 202.00, 303 ± 31.33 and 229.3 ± 10.61 cm³, respectively.

Conclusions

The frontal sinus in the Ile de France sheep was limited to the frontal bone without extending into the parietal, temporal, or occipital bones, similar to Saanen goat. This study provided a comprehensive atlas of Ile de France sheep anatomy to internal medicine veterinarians and surgeons.

A human craniofacial life-course: Cross-sectional morphological covariations during postnatal growth, adolescence, and aging

Covariations between anatomical structures are fundamental to craniofacial ontogeny, maturation, and aging and yet are rarely studied in such a cognate fashion. Here, we offer a comprehensive investigation of the human craniofacial complex using freely available software and MRI datasets representing 575 individuals from 0 to 79 years old. We employ both standard craniometrics methods as well as Procrustes-based analyses to capture and document cross-sectional trends. Findings suggest that anatomical structures behave primarily as modules, and manifest integrated patterns of shape change as they compete for space, particularly with relative expansions of the brain during early postnatal life and of the face during puberty. Sexual dimorphism was detected in infancy and intensified during adolescence with gender differences in the magnitude and pattern of morphological covariation as well as of aging. These findings partly support the spatial-packing hypothesis and reveal important insights into phenotypic adjustments to deep-rooted, and presumably genetically defined, trajectories of morphological size and shape change that characterize the normal human craniofacial life-course.

Is it possible to estimate volume of bone defects formed on dry sheep mandibles more practically by secondarily reconstructing section thickness of cone beam computed tomography images?

OBJECTIVES

The purpose of this study was to evaluate the effect of section thickness on volume estimations of bone defects scanned using cone beam computed tomography (CBCT).

METHODS

25 bone defects were prepared on sheep mandibles and scanned using a KaVo 3D eXam (KaVo Dental, Biberach, Germany) CBCT device. Section thickness of images were reconstructed at 0.25, 0.5, and 0.75 mm to estimate the volume of these defects using the semiautomatic segmentation method. The volume averages obtained using microcomputed tomography and Archimedes' method served as reference values. The estimated volumes at each section thickness were compared with the actual volumes using the Friedman test. The accuracy of volume estimation was determined by the percentage error with respect to the reference values, and the mean absolute error (MAE) was calculated.

RESULTS

Volumetric values of bone defects obtained with CBCT at section thicknesses up to 0.5 mm were compatible with the actual volumes (p > 0.05). The percentage errors at section thicknesses of 0.25, 0.5, and 0.75 mm were -5.4%, -7.3%, and -13.1%, respectively. The mean absolute errors were 13.6 mm³, 15.7 mm³, and 18.2 mm³, respectively.

CONCLUSIONS

The section thickness values of CBCT images can be increased to a reasonable level to obtain accurate volume estimation results and save time. The semiautomatic segmentation method can be used reliably for volume estimations of bone defects.

Thalamohippocampal atrophy in focal epilepsy of unknown cause at the time of diagnosis

BACKGROUND AND PURPOSE

Patients with chronic focal epilepsy may have atrophy of brain structures important for the generation and maintenance of seizures. However, little research has been conducted in patients with newly diagnosed focal epilepsy (NDfE), despite it being a crucial point in time for understanding the underlying biology of the disorder. We aimed to determine whether patients with NDfE show evidence of volumetric abnormalities of subcortical structures.

METHODS

Eighty-two patients with NDfE and 40 healthy controls underwent magnetic resonance imaging scanning using a standard clinical protocol. Volume estimation of the left and right hippocampus, thalamus, caudate nucleus, putamen and cerebral hemisphere was performed for all participants and normalised to whole brain volume. Volumes lower than two standard deviations below the control mean were considered abnormal. Volumes were analysed with respect to patient clinical characteristics, including treatment outcome 12 months after diagnosis.

RESULTS

Volume of the left hippocampus (p_(FDR-corr)  = 0.04) and left (p_(FDR-corr)  = 0.002) and right (p_(FDR-corr)  = 0.04) thalamus was significantly smaller in patients relative to controls. Relative to the normal volume limits in controls, 11% patients had left hippocampal atrophy, 17% had left thalamic atrophy and 9% had right thalamic atrophy. We did not find evidence of a relationship between volumes and future seizure control or with other clinical characteristics of epilepsy.

CONCLUSIONS

Volumetric abnormalities of structures known to be important for the generation and maintenance of focal seizures are established at the time of epilepsy diagnosis and are not necessarily a result of the chronicity of the disorder.

Volume estimation of brain ventricles using Cavalieri's principle and Atlas-based methods in Alzheimer disease: Consistency between methods

Automatic estimations of brain ventricles are needed to assess disease progression in neurodegenerative disorders such as Alzheimer Disease (AD). The objectives of this study are to evaluate the diagnostic performances of an automated volumetric assessment tool in estimating lateral ventricle volumes in AD and to compare this with Cavalieri's principle, which is accepted as the gold standard method. This is across-sectional volumetric study including 25 Alzheimer patients and 25 healthy subjects undergoing magnetic resonance images (MRI) with a 3D turbo spin echo sequence at 1.5 Tesla. The Atlas-based method incorporated MRIStudio software to automatically measure he volumes of brain ventricles. To compare the corresponding measurements, we used manual point-counting and semi-automatic planimetry methods based on Cavalieri's principle. Bland-Altman test results indicated an excellent agreement between Cavalieri's principle and the Atlas-based method in all volumetric measurements (p < 0.05). We obtained a 64% sensitivity and 92% specificity for lateral ventricular volumes according to the Atlas-based method. AD subjects had significantly larger left and right lateral ventricle volume (LVV) when compared to control subjects in respect to three volumetric methods (p < 0.01). Lateral ventricle-to-brain ratio (VBR) statistically increased 49.23% in measurements done with the point-counting method, 45.12% with the planimetry method, and 45.49% with the Atlas-based method in AD patients (p < 0.01). As a result, the Atlas-based method may be used instead of manual volumetry to estimate brain volumes. Additionally, this method provides rapid and accurate estimations of brain ventricular volumes in-vivo examination of MRI.

Anatomy of the head in the Saanen goat: a computed tomographic and cross-sectional approach

The present work aimed to investigate the anatomical structures of the Saanen goat head and its volumetric properties using computed tomography (CT) and stereological methods. Eight adult Saanen goat heads were included in this study. The different cavities and structures of the head, including nasal cavity, paranasal sinuses, oral cavity, orbital cavity, and cranial cavity were evaluated using CT scans, cross, sagittal, and coronal sections. The volume of head cavities and structures were estimated using the Cavalieri method. The results showed that the dorsal, middle and nasal ventral concha contained the dorsal, middle and ventral conchal sinuses, respectively. The paranasal sinuses constituted maxillary, frontal, lacrimal, and ethmoidal that were recognized and named in the CT scan images and their corresponding anatomical cross sections. The palatine and sphenoidal sinuses were not seen in the Saanen goat. Total volume of the head, nasal cavity and cranial cavity was estimated to be 1958 ± 205, 825.4 ± 62.6 and 423.6 ± 48.2 cm³, respectively. The frontal sinus was the largest paranasal sinus with a volume of 281.8 ± 16.9 cm³ and the lacrimal sinus with a volume 50.2 ± 6 cm³ was the smallest one. The ventral conchal sinus with a volume of 26.6 ± 4.5 cm³ and middle conchal sinus with a volume of 13.4 ± 2.6 cm³ were largest and smallest nasal sinuses, respectively. These results may be used as a basic data to provide a reference set for volume of the examined head structures resulting in better and more precise diagnosis of any pathological volume alteration.

Orbital volume measurements from magnetic resonance images using the techniques of manual planimetry and stereology

Introduction:

Current volume measurement techniques, for the orbit, are time-consuming and involve complex assessments, which prevents their routine clinical use. In this study, we evaluate the applicability and efficacy of stereology and planimetry in orbital volume measurements using magnetic resonance imaging (MRI).

Materials and Methods:

Prospective imaging study using MRI. Sheep craniums and human subjects were evaluated. Water-filling measurements were performed in animal skulls, as the standard validation technique. Planimetry and stereology techniques were used in each dataset. Intraobserver and interobserver reliability testing were applied.

Results:

In stereology customization, 1/6 systematic sampling scheme was determined as optimal with acceptable coefficient of error (3.09%) and low measurement time (1.2 min). In sheep craniums, the mean volume measured by water displacement, planimetry, and stereology was 17.81 ± 0.59 cm³, 18.53 ± 0.24 cm³, and 19.19 ± 0.17 cm³, respectively. Planimetric and stereological methods were highly correlated (r = 0.94; P ≈ 0.001). The mean difference of the orbital volume using planimetry and stereology was 0.316 ± 0.168 cm³. In human subjects, using stereology, the mean orbital volume was found to be 19.62 ± 0.2 cm³ with a CE of 3.91 ± 0.15%.

Conclusions:

The optimized stereological method was found superior to manual planimetry in terms of user effort and time spent. Stereology sampling of 1/6 was successfully applied in human subjects and showed strong correlation with manual planimetry. However, optimized stereological method tended to overestimate the orbital volume by about 1 cc, a considerable limitation to be taken in clinical practice.

Osteosarcopenia increases hip fracture risk: A case-controlled study in the elderly

BACKGROUND

The aim of this study was to determine the relationship between bone mineral density (BMD), gluteus maximus muscle volume, and hip fracture type in patients with hip trauma.

METHODS

A total of 134 patients were included in the study; 76 were in the study group [mean age 71.89 (65-80)] (hip fracture group), and 58 were in the control group [mean age 71.27 (65-80)] (hip trauma without fracture). The fracture type, femoral head diameter (FHD), and body mass index (BMI) were assessed. Fracture type was evaluated according to AO/OTA classification. The total gluteus maximus volume t (GMV) was evaluated via computed tomography (CT).

RESULTS

In both groups, there were significant positive correlations between BMD and tGMV/FHD, tGMV/BMI, and tGMV. When comparing the groups regarding total muscle volume, the muscle volume in the control group was significantly higher.

CONCLUSION

According to this study, GMV have an impact on bone mineral density. The risk of hip fracture should not be assessed by only examining bone density in patients over 65 years of age. The clinical relevance is that increasing the gluteal muscle volume above cut-off value in elderly individuals may help to reduce hip fracture risk.

The estimation of bone cyst volume using the Cavalieri principle on computed tomography images

PURPOSE

To evaluate the volume of bone cyst using the planimetry method of the Cavalieri principle.

METHODS

A retrospective analysis was carried out on data from 25 computed tomography (CT) images of patients with bone cyst. The volume of the cysts was calculated by two independent observers using the planimetry method. The procedures were repeated 1 month later by each observer.

RESULTS

The overall mean volume of the bone cyst was 29.25 ± 25.86 cm³. The mean bone cyst volumes calculated by the first observer for the first and second sessions were 29.18 ± 26.14 and 29.27 ± 26.19 cm³, respectively. The mean bone cyst volumes calculated by the second observer for the first and second sessions were 29.32 ± 26.36 and 29.23 ± 26.36 cm³, respectively. Statistical analysis showed no difference and high agreement between the first and second measurements of both observers. The Bland-Altman plots showed strong intraobserver and interobserver concordance in the measurement of the bone cyst volume. The mean total time necessary to obtain the cyst volume by the two observers was 5.27 ± 2.30 min.

CONCLUSION

The bone cyst of the patients can be objectively evaluated using the planimetry method of the Cavalieri principle on CT. This method showed high interobserver and intraobserver agreement. This volume measurement can be used to evaluate cyst remodeling, including complete healing and cyst recurrence.

Pericardin, a Drosophila collagen, facilitates accumulation of hemocytes at the heart

Hematopoietic cell lineages support organismal needs by responding to positional and systemic signals that balance proliferative and differentiation events. Drosophila provides an excellent genetic model to dissect these signals, where the activity of cues in the hemolymph or substrate can be traced to determination and differentiation events of well characterized hemocyte types. Plasmatocytes in third instar larvae increase in number in response to infection and in anticipation of metamorphosis. Here we characterize hemocyte clustering, proliferation and transdifferentiation on the heart or dorsal vessel. Hemocytes accumulate on the inner foldings of the heart basement membrane, where they move with heart contraction, and are in proximity to the heart ostia and pericardial nephrocytes. The numbers of hemocytes vary, but increase transiently before pupariation, and decrease by 4 h before pupa formation. During their accumulation at the heart, plasmatocytes can proliferate and can transdifferentiate into crystal cells. Serrate expressing cells as well as lamellocyte-like, Atilla expressing ensheathing cells are associated with some, but not all hemocyte clusters. Hemocyte aggregation is enhanced by the presence of a heart specific Collagen, Pericardin, but not the associated pericardial cells. The varied and transient number of hemocytes in the pericardial compartment suggests that this is not a hematopoietic hub, but a niche supporting differentiation and rapid dispersal in response to systemic signals.

Inter- and intra-rater reliability of computer-assisted planimetry in experimental stroke research

BACKGROUND

Computer-assisted planimetry is widely used in experimental stroke research to assess the size of the ischemic lesion or hemispheric volume.

NEW METHOD

Only insufficient data exist on the training required to achieve sufficient reliability in planimetry. Therefore, planimetry was performed over 15 months by two blinded raters who were initially inexperienced in the method. For inter-rater reliability, the hemispheric and lesional volume of 227 male Wistar Unilever rats subjected to middle cerebral artery occlusion were determined in diffusion- and T2-weighted sequences. For the intra-rater agreement, one investigator assessed the hemispheric and lesional volume in 87 T2-weighted sequences twice within a six-week interval. The correlation was calculated using Krippendorff's alpha and Bland-Altman plots illustrated the agreement.

RESULTS

Inter-rater agreement increased during the first seven weeks and remained at high values (Krippendorff's alpha > 0.88). For intra-rater agreement, Krippendorff's alpha was 0.84 for hemispheric and 0.85 for lesional volume. The Bland-Altman plot indicated solid agreement between raters in the absence of systematic errors.

COMPARISON WITH EXISTING METHODS

Simplified geometrical models or automated methods for planimetry can be used to determine lesional volume, but both approaches are inappropriate to assess hemispheric volume.

CONCLUSION

Computer-assisted planimetry can be an appropriate method to determine hemispheric or ischemic lesion volume in rodents but requires a sufficiently long learning period of approximately two months. Even an experienced investigator can generate data with serious variation. Inter- and intra-rater-dependent bias should be considered during the design and performance of respective studies.

Extreme Enlargement of the Cerebellum in a Clade of Teleost Fishes that Evolved a Novel Active Sensory System

Brains, and the distinct regions that make up brains, vary widely in size across vertebrates [1, 2]. Two prominent hypotheses have been proposed to explain brain region scaling evolution. The mosaic hypothesis proposes that changes in the relative sizes of particular brain regions are the result of selection acting independently on those regions [2, 3]. The concerted hypothesis proposes that the brain evolves as a coordinated structure due to developmental constraints [4]. These hypotheses have been widely debated [3-7], and recent studies suggest a combination of the two best describes vertebrate brain region scaling [8-10]. However, no study has addressed how the mosaic and concerted models relate to the evolution of novel behavioral phenotypes. We addressed this question using African mormyroid fishes. The mormyroids have evolved a novel active electrosensory system and are well known for having extreme encephalization [11] and a large cerebellum [2, 12], which is cited as a possible example of mosaic evolution [2]. We found that compared to outgroups without active electrosensing, mormyroids experienced mosaic increases in the sizes of the cerebellum and hindbrain, and mosaic decreases in the sizes of the telencephalon, optic tectum, and olfactory bulb. However, the evolution of extreme encephalization within mormyroids was associated with concerted changes in the sizes of all brain regions. This suggests that mosaic evolutionary change in the regional composition of the brain is most likely to occur alongside the evolution of novel behavioral functions, but not with the evolution of extreme encephalization.

Ex vivo orbital volumetry using stereology and CT imaging: A comparison with manual planimetry

OBJECTIVES

To evaluate the applicability of stereology and planimetry in orbital volume measurements using computed tomography (CT) and to compare the results between the two measurements.

METHODS

Experimental study using sheep craniums for CT imaging. Water filling measurements were performed, as the validation technique. Quantification techniques were also evaluated in five human subjects. To examine the proportion of agreement among measurements, we tested intra- and inter-observer agreement.

RESULTS

For stereology customization, a 1/8 systematic sampling scheme was considered as optimal; this resulted in a low coefficient of error (2.59 %) and low measurement time (1.9 mins). In sheep craniums, mean volume measured by water displacement, planimetry and stereology was 17.81 ± 0.59 cm³, 17.87 ± 0.68 cm³ and 17.54 ± 0.49 cm³, respectively. Total volumes, obtained by stereology, were highly correlated with the water-filling method (r=0.893; p = 0.001) and a paired t-test showed significant difference between methods (t=3.047; p = 0.014). Planimetry results displayed a high correlation with the water-filling method (r=0.957; p ≈ 0.001) but no statistically significant difference was found (p = 0.154). Mean difference using planimetry and stereology was 0.332 ± 0.322 cm³. In human subjects, using stereology, the estimated volume ranged between 18.57 cm³ and 19.27 cm³, and the mean orbital volume was 19.05 ± 0.50 cm³ with CE=3.75 ± 0.16 %. Mean measure time was 2.1 ± 0.1 mins.

CONCLUSIONS

Stereological measurements were superior to manual planimetry in terms of user effort and time spent. Stereology sampling of 1/8 was successfully applied in human subjects and yielded a strong correlation with manual planimetry.

KEY POINTS

• Stereology can be applied to measure the orbital volume using computed tomography. • Stereological measurements display high correlation with gold standard planimetry and combine low coefficient of error (2.59%) with low measurement time (1.9 min). • Stereology is superior in terms of user effort and time spent.

Assessment of neonatal brain volume and growth at different postmenstrual ages by conventional MRI

Data regarding neonatal brain volumes represent a basis for monitoring early brain development, and large sample of neonatal brain volume data has not been well described. This study was focused on neonatal brain volumes at different postmenstrual ages (PMA) and postnatal age (PNA).A cohort of 415 neonates with PMA 30 to 43 weeks were recruited for the determination of brain volumes. Intracranial cavity (ICC), total brain tissue (TBT), and cerebrospinal fluid (CSF) were evaluated on the basis of T1-weighted sagittal plane magnetic resonance images. Brain magnetic resonance imaging was assessed using maturation scoring system and multiple linear regression analysis was conducted to forecast the effect factors of brain volumes.TBT volume reached a peak growth at 39 to 40 weeks, ICC volume presented peak growth later at around 43 to 44 weeks, and CSF had a cliff fallen at 37 to 38 weeks PMA at scan. The maturation score increased along with PMA, and the TBT and CSF volumes were significantly different between higher and lower gestational age (GA) groups. The ICC and TBT volumes in higher GA group were larger than lower GA group. Most infants in higher GA group had higher TMS than those in lower GA group. Gender, PMA, PNA, and birth weight were predictors of TBT and ICC volumes.Our results showed that premature volumes of ICC and TBT enlarged with the increasing PMA, while volumes of CSF decreased at 37 weeks. Premature earlier to leave the uterus can lead to brain mature retard although they had the same GA compared with those later birth neonates.

The effects of stabilization splint treatment on the volume of masseter muscle in sleep bruxism patients

OBJECTIVE

The aim of this study was to evaluate, quantitatively, the volumetric effects of stabilization splint therapy on the masseter muscle of sleep bruxism (SB) patients.

METHODS

The magnetic resonance (MR) images of 16 SB patients diagnosed by polysomnography (PSG) who used stabilization splints for four months were obtained before and after the therapy. The masseter muscle volume was calculated using Cavalieri's principle on the MR images.

RESULTS

After the splint therapy, the mean volume of the masseter muscle did not reduce significantly. The fat and/or water content of the muscles did not change either.

DISCUSSION

The stabilization splint therapy had no effect on the volume, fat and/or water content of the masseter muscle; however the discomfort was reduced in the patients. Although the effect of splint therapy is not fully understood, the non-invasive and reversible stabilization splint can be used in SB patients because of its relaxation effect on muscles.

Hippocampal Gray Volumes Increase in Treatment-Resistant Depression Responding to Vagus Nerve Stimulation

BACKGROUND

Changes in hippocampal gray matter volumes are proposed to be involved in pathogenesis, course, and treatment response of major depressive disorder. Converging evidence suggests that reduced neurogenesis may occur in treatment-resistant depression (TRD). Vagus nerve stimulation (VNS) is a well-defined, long-term brain stimulation treatment for TRD. However, its in vivo positive effect on hippocampal modulation as mechanism of action has never been investigated before in clinical studies. In this study, we intended to explore hippocampal volumetric changes and clinical antidepressant responses in patients with TRD after 6 and 12 months of treatment with VNS.

METHODS

The TRD outpatients were evaluated for VNS implantation. Right and left hippocampal volumes in 6 TRD patients, who met the criteria for VNS treatment, were measured at baseline before the implantation and after 6 and 12 months. The patients were assessed using Beck Depression Inventory and Hamilton Depression Rating Scale at baseline and at follow-up visits.

RESULTS

There was a statistically significant and progressive increase in right and left hippocampal volumes during the follow up (P < 0.05). Furthermore, patients showed a significant improvement on Hamilton Depression Rating Scale and Beck Depression Inventory scores (P < 0.05).

CONCLUSIONS

Our data suggest a VNS modulatory effect on hippocampal plasticity as measured by hippocampal gray volume increase in TRD patients. These preliminary findings indicate the fundamental role of hippocampal remodeling as a marker of response to VNS in TRD.

The reliability of Cavalier's principle of stereological method in determining volumes of enchondromas using the computerized tomography tools

INTRODUCTION

Volumetric measurements of benign tumors enable surgeons to trace volume changes during follow-up periods. For a volumetric measurement technique to be applicable, it should be easy, rapid, and inexpensive and should carry a high interobserver reliability. We aimed to assess the interobserver reliability of a volumetric measurement technique using the Cavalier's principle of stereological methods.

MATERIALS AND METHODS

The computerized tomography (CT) of 15 patients with a histopathologically confirmed diagnosis of enchondroma with variant tumor sizes and localizations was retrospectively reviewed for interobserver reliability evaluation of the volumetric stereological measurement with the Cavalier's principle, V = t × [((SU) × d) /SL]2 × Σ P.

RESULTS

The volumes of the 15 tumors collected by the observers are demonstrated in Table 1. There was no statistical significance between the first and second observers ( p = 0.000 and intraclass correlation coefficient = 0.970) and between the first and third observers ( p = 0.000 and intraclass correlation coefficient = 0.981). No statistical significance was detected between the second and third observers ( p = 0.000 and intraclass correlation coefficient = 0.976).

CONCLUSION

The Cavalier's principle with the stereological technique using the CT scans is an easy, rapid, and inexpensive technique in volumetric evaluation of enchondromas with a trustable interobserver reliability.

Comparative Lateralizing Ability of Multimodality MRI in Temporal Lobe Epilepsy

Purpose. The objective is to compare lateralizing ability of three quantitative MR (qMRI) modalities to depict changes of hippocampal architecture with clinical entities in temporal lobe epilepsy. Methods. We evaluated 14 patients with clinical and EEG proven diagnosis of unilateral TLE and 15 healthy volunteers. T1-weighted 3D dataset for volumetry, single-voxel ¹H MR spectroscopy (MRS), and diffusion tensor imaging (DTI) were performed for bilateral hippocampi of all subjects. Results. Individual volumetric measurements provided accurate lateralization in 85% of the patients, spectroscopy in 57%, and DTI in 57%. Higher lateralization ratios were acquired combining volumetry-spectroscopy (85%), spectroscopy-DTI (85%), and volumetry-DTI (100%). Significantly decreased NAA/(Cho+Cr) ratios (p = 0.002) and increased FA (p = 0.001) values were obtained in ipsilateral to epileptogenic hippocampus. Duration of epilepsy and FA values showed a significant negative correlation (p = 0.016, r = −0.847). The history of febrile convulsion associated with ipsilateral increased ADC values (p = 0.015, r = 0.851) and reduced NAA/(Cho+Cr) ratios (p = 0.047, r = −761). Conclusion. Volumetry, MRS, and DTI studies provide complementary information of hippocampal pathology. For lateralization of epileptogenic focus and preoperative examination, volumetry-DTI combination may be indicative of diagnostic accuracy.

Palatine tonsil volume estimation using different methods after tonsillectomy

This study was carried out to measure the volume of the palatine tonsil in otorhinolaryngology outpatients with complaints of adenotonsillar hypertrophy and chronic tonsillitis who had undergone tonsillectomy. To date, no study has investigated palatine tonsil volume using different methods and compared with subjective tonsil size in the literature. For this purpose, we used three different methods to measure palatine tonsil volume. The correlation of each parameter with tonsil size was assessed. After tonsillectomy, palatine tonsil volume was measured by Archimedes, Cavalieri and Ellipsoid methods. Mean right-left palatine tonsil volumes were calculated as 2.63 ± 1.34 cm³ and 2.72 ± 1.51 cm³ by the Archimedes method, 3.51 ± 1.48 cm³ and 3.37 ± 1.36 cm³ by the Cavalieri method, and 2.22 ± 1.22 cm³ and 2.29 ± 1.42 cm³ by the Ellipsoid method, respectively. Excellent agreement was found among the three methods of measuring volumetric techniques according to Bland-Altman plots. In addition, tonsil grade was correlated significantly with tonsil volume.

KCa3.1 inhibition switches the phenotype of glioma-infiltrating microglia/macrophages

Among the strategies adopted by glioma to successfully invade the brain parenchyma is turning the infiltrating microglia/macrophages (M/MΦ) into allies, by shifting them toward an anti-inflammatory, pro-tumor phenotype. Both glioma and infiltrating M/MΦ cells express the Ca²⁺-activated K⁺ channel (KCa3.1), and the inhibition of KCa3.1 activity on glioma cells reduces tumor infiltration in the healthy brain parenchyma. We wondered whether KCa3.1 inhibition could prevent the acquisition of a pro-tumor phenotype by M/MΦ cells, thus contributing to reduce glioma development. With this aim, we studied microglia cultured in glioma-conditioned medium or treated with IL-4, as well as M/MΦ cells acutely isolated from glioma-bearing mice and from human glioma biopsies. Under these different conditions, M/MΦ were always polarized toward an anti-inflammatory state, and preventing KCa3.1 activation by 1-[(2-Chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34), we observed a switch toward a pro-inflammatory, antitumor phenotype. We identified FAK and PI3K/AKT as the molecular mechanisms involved in this phenotype switch, activated in sequence after KCa3.1. Anti-inflammatory M/MΦ have higher expression levels of KCa3.1 mRNA (kcnn4) that are reduced by KCa3.1 inhibition. In line with these findings, TRAM-34 treatment, in vivo, significantly reduced the size of tumors in glioma-bearing mice. Our data indicate that KCa3.1 channels are involved in the inhibitory effects exerted by the glioma microenvironment on infiltrating M/MΦ, suggesting a possible role as therapeutic targets in glioma.

Automated Segmentation of Kidneys from MR Images in Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND AND OBJECTIVES

Our study developed a fully automated method for segmentation and volumetric measurements of kidneys from magnetic resonance images in patients with autosomal dominant polycystic kidney disease and assessed the performance of the automated method with the reference manual segmentation method.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Study patients were selected from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease. At the enrollment of the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease Study in 2000, patients with autosomal dominant polycystic kidney disease were between 15 and 46 years of age with relatively preserved GFRs. Our fully automated segmentation method was on the basis of a spatial prior probability map of the location of kidneys in abdominal magnetic resonance images and regional mapping with total variation regularization and propagated shape constraints that were formulated into a level set framework. T2-weighted magnetic resonance image sets of 120 kidneys were selected from 60 patients with autosomal dominant polycystic kidney disease and divided into the training and test datasets. The performance of the automated method in reference to the manual method was assessed by means of two metrics: Dice similarity coefficient and intraclass correlation coefficient of segmented kidney volume. The training and test sets were swapped for crossvalidation and reanalyzed.

RESULTS

Successful segmentation of kidneys was performed with the automated method in all test patients. The segmented kidney volumes ranged from 177.2 to 2634 ml (mean, 885.4±569.7 ml). The mean Dice similarity coefficient ±SD between the automated and manual methods was 0.88±0.08. The mean correlation coefficient between the two segmentation methods for the segmented volume measurements was 0.97 (P<0.001 for each crossvalidation set). The results from the crossvalidation sets were highly comparable.

CONCLUSIONS

We have developed a fully automated method for segmentation of kidneys from abdominal magnetic resonance images in patients with autosomal dominant polycystic kidney disease with varying kidney volumes. The performance of the automated method was in good agreement with that of manual method.

Geometry-independent assessment of renal volume in polycystic kidney disease from magnetic resonance imaging

Total renal volume (TRV) is an important quantitative indicator of the progression of autosomal dominant polycystic kidney disease (ADPKD). The Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease proposes a method for TRV computation based on manual tracing and geometric modeling. We developed a fast and nearly-automated technique for kidney segmentation and automatically compute TRV. In this study we aim to compare TRV estimates derived from these two different approaches. The highly-automated technique for the analysis of MR images was tested on 30 ADPKD patients. TRV was computed from both axial and coronal acquisitions, and compared to measurements based on geometric modeling by linear regression and Bland Altman analysis. In addition, to assess reproducibility, intra-observer and inter-observer variabilities were computed. The results of this study provide the feasibility of using a nearly-automated approach for accurate and fast evaluation of TRV also in markedly enlarged ADPKD kidneys.

Efficacy of Combined Use of Different Nickel-Titanium Files on Removing Root Canal Filling Materials

INTRODUCTION

The aim of this study was to estimate the remaining amount of residual filling materials in root canals after retreatment using ProTaper Universal Retreatment (PTUR) files (Dentsply Maillefer, Ballaigues, Switzerland) alone or with the additional use of the Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), Reciproc (VDW, Munich, Germany), or Hedström-files (H-file; VDW, Antaeos, Munich, Germany) with volumetric estimation using the stereologic method via cone-beam computed tomographic images.

METHODS

Forty-eight mandibular premolars with single canals were used. The canals were instrumented with ProTaper rotary instruments up to F4 and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). All the samples were placed into the silicone models. Samples were scanned with cone-beam computed tomographic imaging and assigned into 4 groups (n = 12) according to retreatment files: the PTUR system group, the PTUR system plus SAF group, the PTUR system plus Reciproc group, and the PTUR system plus H-file group. The specimens were rescanned after retreatment procedures, and the volume estimations of the remaining filling materials were performed using the stereologic method. Data were analyzed using Kruskal-Wallis and Dunn tests.

RESULTS

There was no significant difference among the groups regarding mean percentage volumes of the filling materials before retreatment procedures (P > .05). None of the retreatment procedures provided complete removal of the filling materials. The additional use of the SAF did not significantly improve the removal of filling materials when compared with the PTUR system alone (P > .05). However, the additional use of Reciproc or hand H-files significantly improved the removal of filling materials when compared with the PTUR system alone (P < .05).

CONCLUSIONS

The additional use of files with different motion kinetics improved the removal of root canal fillings; however, none of the systems completely removed the root canal filling material from the root canals.

Stereological and Morphometric Analysis of MRI Chiari Malformation Type-1

Objective

In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements.

Methods

A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development.

Results

Tonsillar herniation length was measured 9.09±3.39 mm below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased.

Conclusion

Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

Reliability of Total Renal Volume Computation in Polycystic Kidney Disease From Magnetic Resonance Imaging

RATIONALE AND OBJECTIVES

Total renal volume (TRV) is an important quantitative indicator of the progression of autosomal dominant polycystic kidney disease (ADPKD). The Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease proposes a method for TRV computation based on manual tracing and geometric modeling. Alternative approaches for TRV computation are represented by the application of advanced image processing techniques. In this study, we aimed to compare TRV estimates derived from these two different approaches.

MATERIALS AND METHODS

The nearly automated technique for the analysis of magnetic resonance (MR) images was tested on 30 ADPKD patients. TRV was computed from both axial (KVax) and coronal (KVcor) acquisitions and compared to measurements based on geometric modeling (KVap) by linear regression and Bland-Altman analysis. In addition, to assess reproducibility, intraobserver and interobserver variabilities were computed.

RESULTS

Linear regression analysis between KVax and KVcor resulted in an excellent correlation (KVax = 1KVcor - 0.78; r(2) = 0.997). Bland-Altman analysis showed a negligible bias and narrow limits of agreement (bias: -11.7 mL; SD: 54.3 mL). Similar results were obtained by comparison of volumes obtained applying the nearly automated method and the one based on geometric modeling (y = 0.98x + 75.9; r(2) = 0.99; bias: -53.7 mL; SD: 108.1 mL). Importantly, geometric modeling does not provide reliable TRV estimates in huge kidney affected by regional deformation. Intraobserver and interobserver variability resulted in very small percentage error <2%.

CONCLUSIONS

The results of this study provide the feasibility of using a nearly automated approach for accurate and fast evaluation of TRV also in markedly enlarged ADPKD kidneys including exophytic cysts.

Stereological Evaluation of the Optic Nerve Volume in Alzheimer Disease

Optic nerve damage occurs in Alzheimer disease (AD) related to the loss of the retinal ganglion cells that contribute fibers to the optic nerve and reduction of the density of axons of the optic nerve. In this study the authors evaluated optic nerve volume changes and the relation between the cerebrum and optic nerve volumes in AD patients. The study evaluated the volumetric measurements of optic nerve by applying the stereological method on magnetic resonance images (MRI). It included age-matched study and control groups, which were composed of 20 patients with probable AD and 20 healthy subjects, respectively. MRIs were analyzed by using the point-counting approach holding Cavalieri principle. There were statistically significant optic nerve volume reduction and cerebral atrophy in AD patients when compared with the age-matched control subjects (P = 0.013, P < 0.001, respectively) but there was no correlation between the optic nerve volume and cerebral volume in AD patients (r = 0.326, P = 0.160). There was a difference between optic nerve volumes of AD and control subjects. The stereological evaluation of optic nerve volume is of importance for both clinicians and anatomists and it can provide valuable information in the evaluation of morphological changes of AD in vivo.

Assessment of the ABC/2 Method of Epidural Hematoma Volume Measurement as Compared to Computer-Assisted Planimetric Analysis

BACKGROUND AND OBJECTIVE

Epidural hematoma volume (EDHV) is an independent predictor of prognosis in patients with epidural hematoma (EDH) and plays a central role in treatment decision making. This study's objective was to determine the accuracy and reliability of the widely used volume measurement method ABC/2 in estimating EDHV by comparing it to the computer-assisted planimetric method.

METHODS

A data set of computerized tomography (CT) scans of 35 patients with EDH was evaluated to determine the accuracy of ABC/2 method, using computer-assisted planimetric technique to establish the reference criterion of EDHV for each patient. Another data set was constructed by randomly selecting 5 patients then replicating each case twice to yield 15 patients. Intra- and interobserver reliability were evaluated by asking four observers to independently estimate EDHV for the latter data set using the ABC/2 method.

RESULTS

Estimation of EDHV using the ABC/2 method showed high intra- and interobserver reliability (intra-class correlation coefficient = .99). These estimates were closely correlated with planimetric measures (r = .99). But the ABC/2 method generally overestimated EDHV, especially in the nonellipsoid-like group. The difference between the ABC/2 measures and planimetric measures was statistically significant (p < .05).

CONCLUSIONS

The ABC/2 method could be used for EDHV measurement, which would contribute to treatment decision making as well as clinical outcome prediction. However, clinicians should be aware that the ABC/2 method results in a general volume overestimation. Future studies focusing on justification of the technique to improve its accuracy would be of practical value.

A stereological assessment method for estimating the surface area of cycloids

OBJECTIVE

In this study, we sought to determine differences in estimations of surface area made by classical vertical uniform random (VUR) section series and vertical section series obtained perpendicular to a fixed horizontal plane.

MATERIALS AND METHODS

One volunteer subject (male, 25 years of age) with no neurological deficit was chosen at random from a bank of controls in the magnetic resonance (MR) image data library of the Department of Radiology. First, a soccer ball with known geometrical features (radius: 9.75 cm) was imaged using a T1-weighted MR scanner at 5-mm thickness (total 40 sections) to test the validity and reliability of surface area and volume measurements obtained via stereological methods. Second, T1-weighted MR section profiles were obtained from a volunteer individual. Surface area and volume estimation procedures were carried out using the Stereo Investigator 6, MicroBright-Field, Inc., USA.

CONCLUSIONS

We determined that there are no differences in either surface area or volume estimations made using VUR sections and direct vertical sections. We have performed an exhaustive series analysis with a variety of objects.

Endocranial and masticatory muscle volumes in myostatin-deficient mice

Structural and functional trade-offs are integral to the evolution of the mammalian skull and its development. This paper examines the potential for enlargement of the masticatory musculature to limit the size of the endocranial cavity by studying a myostatin-deficient mouse model of hypermuscularity (MSTN-/-). The study tests the null prediction that the larger MSTN-/- mice have larger brains compared with wild-type (WT) mice in order to service the larger muscles. Eleven post-mortem MSTN-/- mice and 12 WT mice were imaged at high resolution using contrast enhanced micro-CT. Masticatory muscle volumes (temporalis, masseter, internal and external pterygoids) and endocranial volumes were measured on the basis of two-dimensional manual tracings and the Cavalieri principle. Volumes were compared using Kruskal-Wallis and Student's t-tests. Results showed that the masticatory muscles of the MSTN-/- mice were significantly larger than in the WT mice. Increases were in the region of 17-36% depending on the muscle. Muscles increased in proportion to each other, maintaining percentages in the region of 5, 10, 21 and 62% of total muscle volume for the external ptyergoid, internal pterygoid, temporalis and masseter, respectively. Kruskal-Wallis and t-tests demonstrated that the endocranial volume was significantly larger in the WT mice, approximately 16% larger on average than that seen in the MSTN-/- mice. This comparative reduction of MSTN-/- endocranial size could not be explained in terms of observer bias, ageing, sexual dimorphism or body size scaling. That the results showed a reduction of brain size associated with an increase of muscle size falsifies the null prediction and lends tentative support to the view that the musculature influences brain growth. It remains to be determined whether the observed effect is primarily physical, nutritional, metabolic or molecular in nature.

Unbiased and efficient estimation of the volume of the fibroid uterus using the Cavalieri method and magnetic resonance imaging

The aim of our study was to develop a reliable technique for measuring volume of the fibroid uterus using Magnetic Resonance Imaging. We applied the Cavalieri method and standard calliper technique to measure the volume of the uterus and largest fibroid in 26 patients, and results were compared with "gold-standard" planimetry measurements. We found Cavalieri measurements to be unbiased, while calliper measurements systematically underestimated uterine volume (- 13.2%, P < 10(-5)) and had greater variance. Repeatability was similar for the 2 techniques (standard deviation [SD] = 4.0%-6.9%). Reproducibility of Cavalieri measurements was higher for measurement of uterine (SD = 9.0%) than fibroid volume (SD = 19.1%), whereas the reproducibility of calliper measurements was higher for fibroid (SD = 9.1%) than uterine volume (SD = 15.9%). The additional measurement time for the Cavalieri method was approximately 1 to 2 minutes. In conclusion, the Cavalieri method permits more accurate measurement of uterine and fibroid volumes and is suitable for application in both clinical practice and scientific research.

New method for estimating the volume and volume fractions of the nasal structures in the goose (Anser anser domesticus) using computed tomography images

1. The conchae within the nasal cavity of poultry are important for water and energy conservation, but have not been experimentally evaluated. The aim of the present study was to determine the accuracy of volume and volume fraction estimates of the conchae, nasal septum and nasal cavity. 2. The nasal cavities of 7 adult goose heads were scanned using computed tomography (CT), with images sampled randomly at a 1/5 sampling fraction. Physical sections were obtained from the same samples, using an electric saw that had an adjustable section range, and provided 14 to 15 sections with a thickness of 2.5 mm. The section surface areas of the nasal cavity, nasal septum and conchae were estimated using the Cavalieri principle. Results obtained using the CT and physical section images were compared. Volumes and volume fractions obtained from the physical sections were accepted as the gold standard and differences in the CT images were determined. 3. Multiplication of the data obtained on the CT images with the deviation percentage of the physical sections produced normalised values. No differences were observed between the gold standard data and the CT images. While it was possible to normalise the obtained data using the gold standard values, the raw data could also be used for comparative studies because the deviations from normal would be similar for all groups. 4. Our study showed that the nasal structures could be estimated in vivo using CT images.

Sampling theory and automated simulations for vertical sections, applied to human brain

In recent years, there have been substantial developments in both magnetic resonance imaging techniques and automatic image analysis software. The purpose of this paper is to develop stereological image sampling theory (i.e. unbiased sampling rules) that can be used by image analysts for estimating geometric quantities such as surface area and volume, and to illustrate its implementation. The methods will ideally be applied automatically on segmented, properly sampled 2D images - although convenient manual application is always an option - and they are of wide applicability in many disciplines. In particular, the vertical sections design to estimate surface area is described in detail and applied to estimate the area of the pial surface and of the boundary between cortex and underlying white matter (i.e. subcortical surface area). For completeness, cortical volume and mean cortical thickness are also estimated. The aforementioned surfaces were triangulated in 3D with the aid of FreeSurfer software, which provided accurate surface area measures that served as gold standards. Furthermore, a software was developed to produce digitized trace curves of the triangulated target surfaces automatically from virtual sections. From such traces, a new method (called the 'lambda method') is presented to estimate surface area automatically. In addition, with the new software, intersections could be counted automatically between the relevant surface traces and a cycloid test grid for the classical design. This capability, together with the aforementioned gold standard, enabled us to thoroughly check the performance and the variability of the different estimators by Monte Carlo simulations for studying the human brain. In particular, new methods are offered to split the total error variance into the orientations, sectioning and cycloid components. The latter prediction was hitherto unavailable--one is proposed here and checked by way of simulations on a given set of digitized vertical sections with automatically superimposed cycloid grids of three different sizes. Concrete and detailed recommendations are given to implement the methods.

The effect of slice thickness on the assessment of bone defect volumes by the Cavalieri principle using cone beam computed tomography

The purpose of this study was to investigate the possible effects of section thickness on volume estimations obtained by cone beam computed tomography. Intraosseal cavities representing bone defects on vestibular sides of the two dry sheep mandibles were scanned by a cone beam computed tomography system. Consecutive sections at 0.2, 0.6, 1, 1.4, and 2.2 mm thickness were used to estimate the volumes of the cavities using the Cavalieri principle of stereological methods. Estimated volumes are then compared with the volumes obtained by the Archimedean principle. In 0.2-, 0.6-, and 1-mm-thick slices, the volumes estimated by the Cavalieri principle did not differ from the volumes by the Archimedean principle (p > 0.05). The 0.2 mm slice-thickness group had the highest asymptotic significance value (p = 0.6). Although the thinnest slice appears to provide the most accurate values, slice thickness up to 1 mm can be chosen for volume calculations on CBCT images.

Maternal smoking during pregnancy and fetal organ growth: a magnetic resonance imaging study

Objective

To study whether maternal cigarette smoking during pregnancy is associated with alterations in the growth of fetal lungs, kidneys, liver, brain, and placenta.

Design

A case-control study, with operators performing the image analysis blinded.

Setting

Study performed on a research-dedicated magnetic resonance imaging (MRI) scanner (1.5 T) with participants recruited from a large teaching hospital in the United Kingdom.

Participants

A total of 26 pregnant women (13 current smokers, 13 non smokers) were recruited; 18 women (10 current smokers, 8 nonsmokers) returned for the second scan later in their pregnancy.

Methods

Each fetus was scanned with MRI at 22–27 weeks and 33–38 weeks gestational age (GA).

Main outcome measures

Images obtained with MRI were used to measure volumes of the fetal brain, kidneys, lungs, liver and overall fetal size, as well as placental volumes.

Results

Exposed fetuses showed lower brain volumes, kidney volumes, and total fetal volumes, with this effect being greater at visit 2 than at visit 1 for brain and kidney volumes, and greater at visit 1 than at visit 2 for total fetal volume. Exposed fetuses also demonstrated lower lung volume and placental volume, and this effect was similar at both visits. No difference was found between the exposed and nonexposed fetuses with regards to liver volume.

Conclusion

Magnetic resonance imaging has been used to show that maternal smoking is associated with reduced growth of fetal brain, lung and kidney; this effect persists even when the volumes are corrected for maternal education, gestational age, and fetal sex. As expected, the fetuses exposed to maternal smoking are smaller in size. Similarly, placental volumes are smaller in smoking versus nonsmoking pregnant women.