Rapid estimation of the vertebral body volume: a combination of the Cavalieri principle and computed tomography images

Determination of Species-Specific Differences in Intracranial Volume of Tuj Sheep and Hair Goats Using Stereology and Computed Tomography Methods

The intracranial cavity contains vitally important organs. The brain, cerebellum, meninges and the vessels that supply these organs are located in the intracranial cavity. Therefore, it is important to learn about the intracranial cavity and to study it. However, there is limited information about the intracranial cavity in the veterinary field. The aim of this study was to determine the differences between the intracranial cavities of different species of animals by using stereology and tomography methods, volume calculations and morphometric measurements. In addition, the compatibility of the methods used with each other was investigated. In the study, six male adult goats and six male adult sheep were used. In this study, the intracranial cavities of sheep and goats were calculated by using Cavalieri's principle and 3D modelling using tomography sections. Morphometric measurements were taken over the intracranial space, and index calculations were made. In 3D models using computed tomography, the intracranial volume was 153.31 ± 24.06 cm3 in goats and 128.07 ± 7.93 cm3 in sheep. In the calculation using Cavalieri's principle, it was determined to be 152.73 ± 22.73 cm3 in goats and 126.15 ± 8.38 cm3 in sheep. As a result of the study, the MWCC (maximum width of the cranial cavity) parameter was found to be statistically significant between species (p < 0.05). The two methods used in Bland-Altman analysis were found to be within the limits of agreement, and the methods can be alternative to each other.

Clinical outcomes and spinal growth after posterior hemivertebra resection and short segment fusion in children

To evaluate the corrective effect of posterior hemivertebra resection and short-segment fusion surgery on pediatric patients and to assess the impact of short-segment fixation surgery on vertebral development during follow-up, a retrospective analysis was performed on 28 pediatric patients who underwent posterior hemivertebra resection surgery. The corrective effect was evaluated by comparing indicators such as segmental scoliosis Cobb angle, upper and lower compensatory curves and trunk balance at different time points. Meanwhile, the vertebral and spinal canal diameters of instrumented vertebrae and adjacent noninstrumented vertebrae were measured and compared to assess vertebral and spinal canal development. The correction rate of segmental scoliosis was 72.2%. The estimated mean vertebral volume of the instrumented vertebra was slightly lower than that of the unfused segment at the final follow-up, but the difference was not statistically significant. The growth rate of the spinal canal during follow-up was much smaller than that of the vertebral body. In summary, internal fixation at a young age shows no significant inhibitory effects on spinal development within the fusion segment. Posterior hemivertebra resection and short-segment fusion surgery are safe and effective.

Development and feasibility of new cardiac measurement method using vertebral heart area ratio in dogs

The vertebral heart scale (VHS) is the most common method used for the objective evaluation of heart size, however, VHS cannot evaluate the entire heart area. This retrospective study aimed to evaluate the development and feasibility of vertebral heart area ratio (VHAR=heart area/the fourth thoracic vertebra [T4] body area) as a new cardiac measurement method. A total of 125 dogs considered without clinical heart abnormalities in the pre-anesthetic examination, measurements of the VHS and VHAR using thoracic radiography were compared with computed tomography measurements of the vertebral cardiac volume ratio (VCVR=cardiac volume/T4 body volume) and investigate whether the VHAR values differed between observers. The mean cardiac and T4 body volumes were 116.99 ± 108.07 cm3 and 0.92 ± 0.91 cm3, respectively. The mean values of observers 1 and 2 were 9.9 ± 0.7 v (VHS), 42.64 ± 27.94 cm2 (heart area), and 1.37 ± 0.96 cm2 (T4 body area). Intraclass coefficients were the highest for the heart area, followed by the T4 body area and VHS. The VHAR showed a moderate correlation with VHS in observers 1 (r=0.671) and 2 (r=0.633). The VCVR showed a more positive correlation with VHAR (r=0.573) than with VHS (r=0.426). These results indicated that VHAR could be used as a complement to VHS for heart size measurement, and the high degree of observer agreement for the measurements indicated the measurement reproducibility of VHAR.

Effects of NGF and Photobiomodulation Therapy on Crush Nerve Injury and Fracture Healing: A Stereological and Histopathological Study in an Animal Model

Study Design

A stereological and histopathological study in an animal model.

Objective

This study explores the effects of the nerve growth factor and photobiomodulation therapy on the damaged nerve tissue and fracture healing.

Methods

A total of 24 rabbits were divided into 4 groups: control group (n = 5), nerve growth factor (NGF) group (n = 7), photobiomodulation (PBMT) group (n = 6), and nerve growth factor and photobiomodulation therapy (NGF+PBMT) group (n = 6). The vertical fracture was performed between the mental foramen and the first premolar, and the mental nerve was crushed for 30 seconds with a standard serrated clamp with a force of approximately 50 N in all groups. The control group received an isotonic solution (.02 mL, .09% NaCl) to the operation site locally. The NGF group received 1 μg human NGF-β/.9% .2 mL NaCl solution for 7 days locally. The PBMT group received PBMT treatment (GaAlAs laser, 810 nm, .3 W, 18 J/cm2) every 48 hours for 14 sessions following the surgery. The NGF+PBMT group received both NGF and PBMT treatment as described above. After 28 days, the bone tissues and mental nerves from all groups were harvested and histologically and stereologically analyzed.

Results

According to the stereological results, the volume of the new vessel and the volume of the new bone were significantly higher in the PBMT group than in other groups (P < .001). According to the histopathological examinations, higher myelinated axons were observed in experimental groups than in the control group.

Conclusions

As a result, PBMT has beneficial effects on bone regeneration. Based on the light microscopic evaluation, more regenerated axon populations were observed in the NGF group than in the PBMT and PBMT + NGF groups in terms of myelinated axon content.

Developing Semiautomated Methods to Measure Pre- and Postoperative Syrinx Volumes

Neurosurgeons evaluate MRI scans to document whether surgical treatment has reduced syrinx size. Manual measurement of syrinx volume is time-consuming and potentially introduces operator error and bias. Developing convenient semiautomated volumetric analysis methods may encourage their clinical implementation and improve syringomyelia monitoring. We analyzed 30 SPGR axial MRI scans from 15 pre- and postoperative Chiari I and syringomyelia patients using two semiautomated (SCAT and 3DQI) methods and a manual Cavalieri (CAV) method. Patients' spinal cord and syrinx volumes pre- and postoperatively were compared by paired t-test. A decrease in syrinx volume (mm3) after surgery was detected across all methods. Mean syrinx volume (± SD) measured by CAV (n = 30) was, preoperatively, 4515 mm3 ± 3720, postoperatively 1109 ± 1469; (p = 0.0004). SCAT was, pre, 4584 ± 3826, post, 1064 ± 1465; (p = 0.0007) and 3DQI was, pre, 4027 ± 3805, post, 819 ± 1242; (p = 0.001). 3DQI and CAV detected similar mean spinal cord volumes before (p = 0.53) and after surgery (p = 0.23), but SCAT volumes differed significantly (p = 0.005, p = 0.0001). The SCAT and 3DQI semiautomated methods recorded surgically related syrinx volume changes efficiently and with enough accuracy for clinical decision-making and research studies.

A study on the correlation between spleen volume estimated via cavalieri principle on computed tomography images with basic hemogram and biochemical blood parameters

Considering its hematological and immunological functions, spleen is a very important organ. A change occurs in its size as the spleen performs these functions. This study aims to examine the possible relationships between spleen volume and the basic hemogram and biochemical parameters in serum. Multidetector computed tomography images and basic hemogram and biochemical parameters of 74 adult individuals, 34 male and 40 female, who were found to be healthy, were used in the study. Spleen volume was estimated using the Cavalieri method on multidetector computed tomography images and the correlations between the volume value with basic hemogram and biochemistry parameters were researched. While negative significant correlations were found between the estimated spleen volume and lymphocyte percentage (r=–0.224) and platelet level (r=–0.271); positive significant correlations were found between hemoglobin level (r=0.228), hematocrit level (r=0.237), alanine aminotransferase (r=0.345), and erythrocyte level (r=0.375). As a result of this study, a relationship was found between spleen volume and lymphocyte percentage, hematocrit level, erythrocyte level, platelet level, and alanine aminotransferase level in serum. We believe that the results of the study will provide a larger perspective to clinicians in the diagnosis of diseases associated with spleen.

Morphometric and volumetric analysis of the cervical spinal cord and vertebral canal using computed tomography images in normal Van cats

This study was performed on Van cats to determine the volumetric, morphometric and surface area measurement values of their cervical spinal cords (SC) and vertebral canals (CC) and the ratios between their dimensions using computed tomography (CT) images. The study also aims to reveal any biometric differences in these values between the two sexes. Spinal cord and vertebral canal CT images of 16 healthy adult Van cats (8 males and 8 females) were used in the study. First, three measurement points were selected for each vertebra on their cranial, medial and caudal sections along the sagittal axis. Next, the morphometric values were obtained using the transversal images of these measurement points. The surface areas for the SC and CC were calculated using the stereological planimetry method. The Cavalieri's principle was then used to calculate the relevant anatomic structure volumes. The obtained values were then statistically analysed. SC and CC were found to be larger in males in general, while 'SC cranial/CC cranial' and 'SC medial/CC medial' dimensions and volume ratios were found to be larger in female cats on average. Bodyweight and age values were found to have a negative correlation with SC and CC ratio, but the correlation was statistically insignificant. All SC and CC surface area and volume measurements were found to be higher in male cats (p < .05). We believe the results obtained by this study will provide valuable insight into veterinary clinicians in evaluating pathological lesions in the cervical spinal cord and vertebral canal CT scans.

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.

Evaluation of Volume of Nasopharyngeal Cancers by the Cavalieri Principle

Prediction of tumor volume using the Cavalieri method may be helpful in management of therapy and evaluation of treatment results. The aim of this study was to adapt the Cavalieri stereological method to magnetic resonance imaging for determining volume of nasopharyngeal cancers and assess changes after treatment using the Cavalieri method. Serial MRI images in the sagittal plane were obtained from a total of 33 patients with nasopharyngeal carcinomas (11 with stage T2, 11 with stage T3, and 11 with stage T4 lesions). The images were analyzed retrospectively before and two months following the cessation of radiochemotherapy for comparison. Average tumor volumes before and after treatment in patients with stage T2 were 21. 5±10.5 cm3 and 2.82±3.43 cm³, respectively (p=0.000). The respective figures were 35.1±19.0 cm3 and 6.27±7.82 cm³ (p=0.000) for stage T3 cases, and 62.8±27.8 cm3 and 11. 6±11.9 cm3 (p=0.000) for stage T4. Post-treatment tumor volumes were statistically reduced when compared to pre-treatment volumes in all stages.

Preventive Effect of Phosphodiesterase Inhibitor Pentoxifylline Against Medication-Related Osteonecrosis of the Jaw: An Animal Study

PURPOSE

The aim of this experimental study was to investigate the prophylactic effect of pentoxifylline (PTX) on medication-related osteonecrosis of the jaw (MRONJ).

MATERIALS AND METHODS

Female Sprague-Dawley rats (n = 33) received zoledronic acid (ZA) for 8 weeks to create an osteonecrosis model. The left mandibular second molars were extracted and the recovery period lasted 8 weeks before sacrifice. PTX was intraperitoneally administered to prevent MRONJ. The specimens were histopathologically and histomorphometrically evaluated.

RESULTS

Histomorphometrically, between the control and ZA groups, there was no statistically significant difference in total bone volume (P = .999), but there was a statistically significant difference in bone ratio in the extraction sockets (P < .001). A comparison of the bone ratio of the ZA group with the ZA/PTX group (PTX administered after extraction) showed no statistically significant difference (P = .69), but there was a statistically significant difference with the ZA/PTX/PTX group (PTX administered before and after extraction; P = .008). Histopathologically, between the control and ZA groups, there were statistically significant differences for inflammation (P = .013), vascularization (P = .022), hemorrhage (P = .025), and regeneration (P = .008). Between the ZA and ZA/PTX groups, there were no statistically significant differences for inflammation (P = .536), vascularization (P = .642), hemorrhage (P = .765), and regeneration (P = .127). Between the ZA and ZA/PTX/PTX groups, there were statistically significant differences for inflammation (P = .017), vascularization (P = .04), hemorrhage (P = .044), and regeneration (P = .04).

CONCLUSION

In this experimental model of MRONJ, it might be concluded that although PTX, given after tooth extraction, improves new bone formation that positively affects bone healing, it is not prophylactic. However, PTX given before tooth extraction is prophylactic. Therefore, PTX might affect healing in a positive way by optimizing the inflammatory response.

Progressive Muscle Cell Delivery as a Solution for Volumetric Muscle Defect Repair

Reconstructing functional volumetric tissue in vivo following implantation remains a critical challenge facing cell-based approaches. Several pre-vascularization approaches have been developed to increase cell viability following implantation. Structural and functional restoration was achieved in a preclinical rodent tissue defect; however, the approach used in this model fails to repair larger (>mm) defects as observed in a clinical setting. We propose an effective cell delivery system utilizing appropriate vascularization at the site of cell implantation that results in volumetric and functional tissue reconstruction. Our method of multiple cell injections in a progressive manner yielded improved cell survival and formed volumetric muscle tissues in an ectopic muscle site. In addition, this strategy supported the reconstruction of functional skeletal muscle tissue in a rodent volumetric muscle loss injury model. Results from our study suggest that our method may be used to repair volumetric tissue defects by overcoming diffusion limitations and facilitating adequate vascularization.

The Local Effect of Puerarin on Critical-Sized Calvarial Defects

Pueraria, the root of Pueraria lobata, is a commonly used herb in alternative medicine. This study evaluates the effect of puerarin and autogenous graft material combination on bone regeneration in calvarial critical-sized bone defects. Twenty-four rats were randomly divided into 3 groups of 8 rats each. A 5-mm diameter critical-sized defect was created in the calvarium of each animal. In group C, defects were left unfilled and were allowed to heal spontaneously without the use of any grafting material. Critical-sized bone defect created in animals receiving no treatment. In group ABG, defects were filled with autologous bone graft only. In group P-ABG, defects were filled with autologous bone graft and puerarin combination. All animals were euthanized at 28 days postoperative. Stereologic analyses were performed. New bone area and connective tissue volumes were measured. Stereologic analysis showed that the difference between grafted groups (P-ABG and ABG) and group C was statistically significant with a mean bone formation of 1.13 ± 0.09, 1.11 ± 0.11, and 0.31 ± 0.09 mm respectively (P ≤0.05). The connective tissue volumes were also statistically higher in groups P-ABG and ABG (P ≤0.05). Puerarin has positive effect on new bone formation in autogenous grafted critical-sized bone defects.

The influence of oral administration of rosuvastatin on calvarial bone healing in rats

The purpose of this study is to investigate the potential of the systemic administration of different doses of rosuvastatin (RSV) on autogenous grafted critical-sized cortical bone defects. Twenty-four rats were divided into three groups: Group C (control), Group RSV-2 and Group RSV-5. A 5-mm diameter critical-size defect was created in the calvarium of each animal. In Group C, the defect was filled by autogenous graft only and rats were given saline solution with oral gavage for 28 days. In Group RSV-2 defects were filled with autogenous graft and rats were given 2 mg/kg rosuvastatin with oral gavage for 28 days. In Group RSV-5 defects were filled with autogenous graft and rats were given 5 mg/kg rosuvastatin with oral gavage for 28 days. All animals were euthanized at 28 days postoperative. Stereologic and micro-CT analyses were performed. New bone area (NBA) and connective tissue volumes were measured. Stereologic analysis showed that Group RSV-5 and RSV-2 had significantly more new bone at 4 weeks compared with group C. Connective tissue volumes were also significantly higher in RSV applicated groups. New bone and connective tissue volumes' difference were not statistically significant between RSV groups. Micro-CT results were similar with stereologic analyses. Orally administered RSV enhances bone regeneration in critical size calvarial rat defects filled with autogenous graft furthermore possible inflammatory effect should be investigated.

Propolis accelerates the consolidation phase in distraction osteogenesis

We evaluated the effect of propolis on new bone formation after distraction osteogenesis (DO). This study examined 3 groups: control group, P100, and P200. Rabbits underwent DO of the left mandible after an osteotomy between the first molar and the mental foramen. Bone mineral content and bone mineral density were evaluated using dual-energy x-ray absorption 1 and 4 weeks after the procedure. The volume of connective tissue and new bone and the number of capillaries were measured using stereologic analysis after the subjects were killed. Dual-energy x-ray absorption showed that the bone mineral content and bone mineral density were higher in the groups treated with propolis by week 4, and these parameters were higher in the P200 group. Stereologic analysis showed no significant differences in connective tissue volume and number of capillaries among the groups. New bone volume was lowest in the P200 group. We concluded that propolis accelerates bone formation and may shorten the consolidation phase with DO.

Estimation of the efficacy of chemo-radiotherapy on tumor regression in the patients with laryngeal cancer via computerized tomography using the Cavalieri method

CONCLUSION

Calculating tumor volume using the Cavalieri method in laryngeal tumors before and after treatment may be useful to optimize the treatment and to minimize the side-effects of radiotherapy.

PURPOSE

This study aimed to estimate the pre-treatment and post-treatment tumor volumes of the patients to whom radiotherapy or radio-chemotherapy was applied as a treatment using Cavalieri's Principle as a stereological method and to assess tumor regression rates in the patients with Laryngeal Squamous Cell Carcinoma (LSCC) statistically.

MATERIALS AND METHOD

Sixteen patients (eight patients with stage T3 and eight patients with stage T4) diagnosed with LCCC bearing the appropriate characteristics to criteria in the otorhinolaryngology clinic were included. Patients had computerized tomography (CT) scans in the axial plane before treatment and 2 months after the treatment. Pre-treatment and post-treatment tumor volumes on CT images were calculated using Cavalieri's principle as a stereological method and then compared.

FINDINGS

Average tumor volumes in patients with stage T3 before and after treatment were 10.12 ± 3.58 cm(3) and 1.33 ± 1.74 cm(3), respectively (p = 0.008). These volumes were 11.92 ± 4.61 cm(3) and 2.17 ± 2.34 cm(3) (p = 0.008) for patients with stage T4, respectively. Post-treatment tumor volumes were statistically reduced compared to pre-treatment volumes in all stages.

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.

A stereological study on the correlation of inferior turbinate hypertrophy and paranasal sinus disease

The objective of this study is to investigate the correlation between inferior turbinate size and paranasal sinus opacification on computerized tomography (CT) scans. Paranasal sinus CT scans of a total of 185 patients (92 males, 93 females) were examined in terms of sinus opacification. Sizes of the inferior turbinates were measured using stereological method and these sizes in normal and opacified paranasal sinuses are compared using one-way analysis of variance. Scans of 185 patients (93 female, 92 male) aged between 12 and 84 (mean 37.85 ± 16.27) years were examined in this study. Sizes of the inferior turbinates were found to be increased significantly in case of opacification of ipsilateral maxillary and anterior ethmoid sinuses (p = 0.000 and p = 0.4, respectively) on both sides. On the other hand, such a relationship could not be demonstrated for sizes of inferior turbinates with opacified or non-opacified posterior ethmoid, frontal and sphenoid sinuses. In conclusion, the combination of CT and the Cavalieri principle can provide an unbiased, direct, and assumption-free estimate of the regions of interest. The presented method can be efficiently applied without any need for special software, additional equipment, or personnel than that required for routine CT in daily use. Paranasal sinus disease, especially the inflammatory diseases of maxillary and anterior ethmoid sinuses, must be carefully investigated in cases with inferior turbinate hypertrophy.

Is sheep lumbar spine a suitable alternative model for human spinal researches? Morphometrical comparison study

Sheep are commonly used as a model for human spinal orthopaedic research due to their similarity in morphological and biomechanical features. This study aimed to document the volumes of vertebral bodies and compare the generated results as well as morphometry of the sheep lumbar spine to human published data. For this purpose, computed tomography scans were carried out on five adult Merino sheep under general anaesthesia. Transverse 5 mm thick images were acquired from L1 to L6 using a multi-detector-row helical CT scanner. Volume measurements were performed with dedicated software. Four spinal indices and Pavlov's ratio were calculated. Thereafter, the generated data were compared to published literature on humans. The mean vertebral body volume showed an increase towards the caudal vertebrae, but there were no significant differences between the vertebral levels (P>0.05). Compared to humans, sheep vertebral body volumes were 48.6% smaller. The comparison of absolute values between both species revealed that sheep had smaller, longer and narrower vertebral bodies, thinner intervertebral discs, narrower spinal canal, longer transverse processes, shorter dorsal spinous processes and narrower, higher pedicles with more lateral angulations. The comparison of the spinal indices showed a good similarity to human in terms of the vertebral endplates and spinal canal. The results of this study may be helpful for using the sheep as a model for human orthopaedic spinal research if anatomical differences are taken into account.

Fundamental ratios and logarithmic periodicity in human limb bones

Fundamental mathematical relationships are widespread in biology yet there is little information on this topic with regard to human limb bone lengths and none related to human limb bone volumes. Forty-six sets of ipsilateral upper and lower limb long bones and third digit short bones were imaged by computed tomography. Maximum bone lengths were measured manually and individual bone volumes calculated from computed tomography images using a stereologic method. Length ratios of femur : tibia and humerus : ulna were remarkably similar (1.21 and 1.22, respectively) and varied little (<7%) between individuals. The volume ratio of femur : tibia was approximately half that of humerus : ulna (1.58 and 3.28, respectively; P < 0.0001). Lower limb bone volume ratios varied much more than upper limb ratios. The relationship between bone length and volume was found to be well described by power laws, with R(2) values ranging from 0.983 to 0.995. The most striking finding was a logarithmic periodicity in bone length moving from distal to proximal up the limb (upper limb λ = 0.72, lower limb λ = 0.93). These novel data suggest that human limb bone lengths and volumes follow fundamental and highly conserved mathematical relationships, which may contribute to our understanding of normal and disordered growth, stature estimation, and biomechanics.

A new evaluation method for the intracranial volume changes and subdural effusion of patients following endoscopic third ventriculostomy

OBJECTIVE

Endoscopic third ventriculostomy (ETV) is a procedure commonly applied in the treatment of non-communicating (obstructive) hydrocephalus. One of the rare complications that can occur following ETV is a subdural effusion, even though this procedure is considered to be a more controlled and natural method of cerebrospinal fluid drainage compared to external drainage. In this study, we evaluated the intracranial volume changes and subdural effusion of patients following ETV using Cavalieri method.

METHOD

Volumes analysis of the cranial cavity, brain, ventricles and subdural effusions of two patients after ETV were performed on computed tomography images using the Cavalieri principle, one of the stereological methods.

RESULTS

The preoperative total intracranial volumes and the preoperative brain volumes decreased for both patients during the postoperative 3rd, 10th and 30th days. Following ETV, the volumes of the lateral ventricles of both patients initially decreased during the postoperative 3rd and 10th days, however, the volumes returned almost to their preoperative size by the end of the 30th day. The effusions were seen on the postoperative 3rd and 10th days resolved by the end of the 30th day.

CONCLUSION

Our results show that the Cavalieri method can be used to unbiased prediction of intracranial volume changes and to follow the subdural effusion after the ETV surgery.

Stereological and histological analysis of the developing rat heart

We studied with quantitative and microscopical methods the heart of rats divided into five age groups: embryos at the age of 11 days, fetuses at the age of 16 days and 20 days and also heart samples of 3-day-old pups and young adults (5 weeks of age) were used (n = 10 samples in each group). At the end of the study; heart samples were obtained from all animals. Stereological estimations were performed on heart volume, volume of heart lumen (ventricles and atria), volume of myocardium, numerical density of the myocyte nuclei and mean nuclear diameter of myocytes. Volumetric values and numerical data were estimated via Cavalieri method and physical dissector, respectively. In this study, histological examination was performed at light and electron microscopic levels. The numerical density of the myocyte nuclei increased from fetuses to young adults. Differences between embryos and fetuses, between fetuses and 3-day-old pups, and between 3-day-old pups and young adults were statistically significant. These results indicate that myogenesis continued in the rat myocardium during prenatal life and after birth.

A stereological study of MRI and the Cavalieri principle combined for diagnosis and monitoring of brain tumor volume

In this study, we aimed to describe the application of the Cavalieri principle for the assessment of tumor volume using MRI without an over-projection/estimation effect. For this purpose, the volume of a patient's brain and the brain tumor volume, or the volume of the former tumor region, were estimated preoperatively and postoperatively using a combination of the Cavalieri principle and MRI. The previously described formula was modified for MRI measurements to eliminate the over-estimation effects of imaging. The total brain and tumor volumes estimated using the MRI of a representative patient with glioblastoma multiforme were: preoperative, 1562.46 cm³ and 81.59 cm³, respectively; and postoperative, 1571.72 cm³ and 86.92 cm³, respectively. The mean time to count points for an estimation of brain and tumor volume (or the volume of the former tumor region) were 14 minutes and 3 minutes, respectively. The coefficients of the errors of the estimates for brain and tumor volume (former tumor volume, postoperative) measurements were: preoperative 0.01 and 0.02; and postoperative 0.01 and 0.03, respectively. Our results show that the combination of MRI and the Cavalieri principle can provide an unbiased, direct and assumption-free estimate of the regions of interest. Therefore, the presented method could be applied efficiently without any need for special software, additional equipment or personnel other than that required for routine MRI in daily use.

Effects of prenatal exposure to a 900 MHz electromagnetic field on the dentate gyrus of rats: a stereological and histopathological study

Electromagnetic fields (EMFs) inhibit the formation and differentiation of neural stem cells during embryonic development. In this study, the effects of prenatal exposure to EMF on the number of granule cells in the dentate gyrus of 4-week-old rats were investigated. This experiment used a control (Cont) group and an EMF exposed (EMF) group (three pregnant rats each group). The EMF group consisted of six offspring (n=6) of pregnant rats that were exposed to an EMF of up to 900 megahertz (MHz) for 60 min/day between the first and last days of gestation. The control group consisted of five offspring (n=5) of pregnant rats that were not treated at all. The offspring were sacrificed when they were 4 weeks old. The numbers of granule cells in the dentate gyrus were analyzed using the optical fractionator technique. The results showed that prenatal EMF exposure caused a decrease in the number of granule cells in the dentate gyrus of the rats (P<0.01). This suggests that prenatal exposure to a 900 MHz EMF affects the development of the dentate gyrus granule cells in the rat hippocampus. Cell loss might be caused by an inhibition of granule cell neurogenesis in the dentate gyrus.

Effect of high fat diet on the volume of liver and quantitative feature of Kupffer cells in the female rat: a stereological and ultrastructural study

BACKGROUND

The role of Kupffer cells (KCs) in nonalcoholic steatohepatitis (NASH) which is regarded as a major cause of cryptogenic cirrhosis of the liver was investigated using stereological methods and electron microscopy in the rat model. To our knowledge, there is no stereological study on the volume of liver, total number, numerical density, and nuclear height of KCs of liver in the female rat fed with a high fat diet (HFD) in the literature.

METHOD

16 female Sprague Dawley rats were randomized into HFD and control group, with HFD and standard diet for 12 weeks, respectively. In this study, two basic research methods were used to analyze the samples. One was histopathological observation at both light and electron microscopic level. The other was stereological methods that consist of Cavalieri principle for liver volume estimation and physical disector method for estimation of numerical density and total number of KCs in the liver.

RESULTS

Liver volume, both mean numerical density and total number of KCs, were statistically increased in HFD rats. Ultrastructurally, a significant decrease in the mean nuclear height of KCs in HFD rats was also found. In the control group, no abnormal change was observed, but in the HFD group, some changes such as diffuse steatosis, mononuclear cell infiltration, necrosis, fibrosis, accumulation of fat droplets and intra-cytoplasmic vacuoles, and swollen mitochondria with irregular membranes were observed in the hepatocytes.

CONCLUSION

The number and activity of KCs are increased significantly in NASH induced by HFD, and KCs might be involved in the pathogenesis of steatohepatitis as previously attributed as a major cause of cryptogenic cirrhosis of the liver.

Inhibitory effect of pinealectomy on the development of cerebellar granule cells in the chick: A stereological study

Melatonin has some effects upon morphological features of various structures in small animals and human being. However, there has been no investigation concerning its physiological role on development of cerebellar granule cells. In this study, the changes induced by pinealectomy procedure on cerebellar development and their granule cell numbers in the chick were investigated using quantitative stereological methods. A total of 15 Hybro Broiler newly hatched chicks were randomly divided into three equal groups: pinealectomy group (n=5) and non-pinealectomized control group (n=5) and sham-operated group (n=5). Pinealectomy procedure and sham operation were done in 3-day-old chicks and all animals were sacrificed for histopathological evaluation and subsequent stereological analysis in the 8th week. Here, it was observed that pinealectomy significantly reduces the granular cell number in cerebellar cortex of the chicks (P<0.001). The present study is the first stereological study to evaluate the histomorphological effects of pinealectomy on the cerebellar granule cells of the chick. We suggest that the granule cell loss in the cerebellar cortex is due to developmental retardation in early postnatal period, although its exact mechanism is not clear. Based on our findings, we intimate that pineal gland/melatonin might play an important role in the development of cerebellar granule cells in the chick.

Comparison of Three Methods for the Estimation of Total Intracranial Volume

There is a well-known close relationship between the total intracranial volume (TIV) and the brain size. Several studies in different countries have estimated the cranial capacity, which indirectly reflects the brain volume. However, we have not seen a study evaluating the results of the methodologies for the assessment of TIV. This study was carried out on 30 normal subjects whose ages ranged between 19 and 77 years old (males, 18; females, 12). Three different methods were used to assess the TIV. The mean (+/-SD) estimated TIV using linear dimensions method in males and females were 1416.8 +/- 64 cm and 1291.9 +/- 152 cm, respectively. The mean estimated TIV using point counting method in males and females was 1474 +/- 93 cm and 1252 +/- 72 cm, respectively. By using the planimetric method of the mean and SD of TIV, male and females were 1492.1 +/- 74 cm and 1319.6 +/- 100 cm, respectively. There were no statistical difference between TIV measurements obtained using the optimized stereologic technique and planimetry (P > 0.05). TIV between males and females was statistically significant (P < 0.001). This study showed that there are minor differences among the given 3 distinct methods. With the disadvantage of requiring more time to apply, the planimetry and point counting methods provide more assumption-free results than the anthropometric approach. However, the anthropometric method can be applied to assess TIV without needing sophisticated tools.

Prediction of Prognosis in Patients with Epidural Hematoma by a New Stereological Method

Epidural hematoma (EH) is a serious clinical event observed in 2% of head trauma patients. Studies regarding the effects of epidural hematoma volume (EHV) on prognosis are not sufficient. In this study, we applied the volume fraction approach of the stereological method to estimate the hematoma to brain volume fraction (HBVF), and investigated the relation between the HBVF and prognosis. Fifty-nine EH patients (46 male and 13 female subjects, with average age of 21 years) admitted to the emergency clinic were included. The HBVF was estimated on the printed films of cranial computed tomography scans. For this purpose, common point counting grids were superimposed over the scan frames. According to the clinical results, patients were divided into three groups as complete recovery (43), disability (8) and exitus (8). The HBVF was compared with the clinical results. HBVF was determined as 4.6% in the patients with recovery, 8.1% in disability, and 7.6% in exitus patients. The HBVF values were lowest in recovery patients, and the difference between the recovery and the other two groups was statistically significant (p=0.007). However, there was no statistically significant difference in HBVF between disability and exitus patients (p>0.05). In conclusion, the HBVF can be an important tool to determine prognosis, and it can be measured using the volume fraction approach of stereological methods as developed in the present study.

Stereological evaluation of treatment response in patients with non-resectable hepatic alveolar echinococcosis using computed tomography via the Cavalieri method

INTRODUCTION

The purposes of this study were to describe and adapt the relevant methods of computed tomography (CT) and stereology to estimate parasitic volume in the liver, to compare the efficiency of benzimidazole treatment in hepatic alveolar echinococcosis (AE), and to determine whether the response rates measured by the stereological method are correlated with those measured by simple volumetric measurements (SVM).

METHODS

Nine eligible patients with non-resectable AE were included in the study. By using their abdominal CT at the baseline and after a year of treatment, treatment responses of the cases were evaluated both by the stereological method via a software and by SVM, retrospectively. The volume estimation was performed in our study using a different approach that consisted of three separate stages combined with the Cavalieri method of modern design stereology.

RESULTS

The response rates were -17 +/- 55% and -12 +/- 37% by the Cavalieri method and SVM, respectively; however, they were not statistically significant (P = 0.59 and 0.21 for the Cavalieri method and SVM, respectively). Although some cases had comparable results, others had different response rates, and the two methods showed no significant correlation (r = -0.31, P = 0.41).

CONCLUSIONS

Because this modified method provides accurate results by reducing margin of errors, even in case of bizarre shape of AE, a correct, unbiased, and reliable management of the cases with AE via this method may be possible. Owing to lack of a correlation with SVM, it is suggested that a measurement via SVM may be wrong and its use in the evaluation of the treatment response in such cases will not be sufficient and completely true.

The effects of section thickness on the estimation of liver volume by the Cavalieri principle using computed tomography images

Estimation of liver volume using routine CT scans has been described previously. We have, however, not found a gold standard study which analyzes the effect of section thickness on the estimation of liver volume using CT images. In the present study, five normal livers obtained from cadavers were scanned using a Spiral CT Scanner (Xpress/GX Toshiba, Tocigi-Ken) in the horizontal plane. Consecutive sections at a thickness of 10, 5 and 1mm were used to estimate the total volume of the livers by means of the Cavalieri principle. With a view to evaluating inter-observer differences, liver volume was estimated by three observers. The estimated volume using the classical volume estimation formula did not concur with the actual volume of the livers obtained by the fluid displacement technique. The section thickness has an over- or under-projection effect on the estimated volume. The obtained volume estimation results were, therefore, calibrated using three different approaches. The volume obtained by the calibration formulae did not differ statistically from actual liver volumes (P<0.05). There were also no significant differences between the performers' estimates (P>0.05). Results showed that the effect of section thickness on the volume estimates could not be omitted and the obtained values could be calibrated using the proposed approaches presented in this study.