3D Versus 2D Ultrasound: Accuracy of Volume Measurement in Human Cadaver Kidneys

Distal sagittal forelimb conformation in young Walloon horses: Radiographic assessment and its relationship with osteochondral fragments

Osteochondral fragments within equine joints are commonly encountered and may predispose to lameness and limitation to sport purposes. Factors leading to this condition include genetic, nutritional and environmental conditions. However, few studies have evaluated the impact of conformation traits and their correlation with osteochondrosis. This study, based on the radiographic screenings of young horses born in Wallonia (266 individuals, 532 forelimbs), evaluated the correlation between foot, fetlock conformations of the front limb, height at the withers and presence of osteochondral fragments. Moreover, for all traits significantly associated with the presence of osteochondral fragments, a Receiver Operator Characteristic (ROC) curve, area under the curve and optimal cut-off value were calculated to predict the occurrence of fragments. Mean dorsal hoof wall angle was 52.36°, dorsal and palmar angle of the third phalanx were respectively 49.83° and 2.99°, and dorsal metacarpophalangeal angle 147.99°. Moreover, the prevalence of upright feet, defined as having an inclined profile of >2° steeper in relation to its contralateral counterpart, was 24%. Increased palmar angle of the distal phalanx was significantly correlated (P < 0.05) with presence of fragments located at the dorso-proximal margin of the proximal phalanx. The associated area under the curve was 0.623 (95% CI: 0528-0.717, P < 0.05) and the optimal cut-off value to predict fragment occurrence was 2.95° (sensitivity 77.3%; specificity 52.9%). Furthermore, the third metacarpal bone diameter of the left forelimb and height at the withers were significantly (P < 0.05) correlated with the presence of osteochondral fragments in general and within tarsocrural and metatarsophalangeal joints specifically. The area under the curve was 0.585 (95% CI: 0.513-0.656, P < 0.05) with an optimal cut-off value of 152.5 cm (sensitivity 85.1%; specificity 31.2%) for height at the withers to predict presence of osteochondral fragment; to predict the occurrence of osteochondral fragment in any joint on the basis of the third metacarpal bone diameter, the area under the curve was 0.595 (95% CI: 0.524-0.667, P <0.05) and the optimal cut-off value 34.9 mm (sensitivity 52.5%; specificity 64.9%). This study provides information about phenotypic traits associated with osteochondral fragments in horses. Although the diagnostic accuracy of these traits to detect osteochondral fragment was limited, the identification of more phenotypic characteristics could, in the future, make it possible to generate models for accurately identifying individuals at high risk of osteochondral fragments on the basis of their phenotype.

Volumetric quantification identifies some left atrial dilations undetected by left atrium:aorta ratio measurements: A prospective echocardiographic study in 155 Cavalier King Charles Spaniels with and without degenerative mitral valve disease

INTRODUCTION

Degenerative mitral valve disease (DMVD) is the most common canine heart disease with a high predisposition in Cavalier King Charles Spaniels (CKCSs). Mitral regurgitation related to DMVD can lead to left atrial (LA) dilation, which is associated with survival time. Left-atrial-to-aortic (LA:Ao) ratio assessed by two-dimensional echocardiography is commonly used to evaluate LA size. The objectives of this prospective observational study were therefore 1) to compare different echocardiographic methods (i.e., monoplane and biplane Simpson's methods of discs (SMOD) and area-length methods (ALM)) in evaluating LA volume (LAvol) in CKCSs, 2) to assess LA volumes according to DMVD severity and, 3) compare the ability of LAvol and LA:Ao ratio to identify LA enlargement in CKCSs with subclinical DMVD (i.e., American College of Veterinary Internal Medicine (ACVIM) stage B).

MATERIALS AND METHODS

155 CKCSs, either healthy or affected by DMVD, were recruited. Variability and concordance between volumetric methods were evaluated. Values were analyzed according to 2019 ACVIM stages.

RESULTS

All Lin's concordance correlation coefficients regarding intra- and inter-observer variability were considered as very good to excellent. Monoplane methods and ALM produced higher values of LAvol than biplane methods and SMOD, respectively. The upper limit of normal end-systolic LAvol/body weight (LASvol/BW) was defined as 0.90 mL/kg. Left atrial volumes significantly increased with ACVIM stages. Additionally, 37% of stage B1 CKCSs demonstrated LA enlargement using LASvol/BW assessment, with significantly lower LASvol/BW values in dogs with regurgitation fraction ≤30% than in others (p<0.01).

CONCLUSION

In CKCSs, LAvol methods are not interchangeable. In ACVIM stage B CKCSs, LAvol quantification is more effective to detect LA enlargement than LA linear measurements.

Value of radiomics-based two-dimensional ultrasound for diagnosing early diabetic nephropathy

Despite efforts to diagnose diabetic nephropathy (DN) using biochemical data or ultrasound imaging separately, a significant gap exists regarding the development of integrated models combining both modalities for enhanced early DN diagnosis. Therefore, we aimed to assess the ability of machine learning models containing two-dimensional ultrasound imaging and biochemical data to diagnose early DN in patients with type 2 diabetes mellitus (T2DM). This retrospective study included 219 patients, divided into a training or test group at an 8:2 ratio. Features were selected using minimum redundancy maximum relevance and random forest-recursive feature elimination. The predictive performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC) for sensitivity, specificity, Matthews Correlation Coefficient, F1 score, and accuracy. K-nearest neighbor, support vector machine, and logistic regression models could diagnose early DN, with AUC values of 0.94, 0.85, and 0.85 in the training cohort and 0.91, 0.84, and 0.84 in the test cohort, respectively. Early DN diagnosing using two-dimensional ultrasound-based radiomics models can potentially revolutionize T2DM patient care by enabling proactive interventions, ultimately improving patient outcomes. Our integrated approach showcases the power of artificial intelligence in medical imaging, enhancing early disease detection strategies with far-reaching applications across medical disciplines.

Clinical Reproducibility of the Stone Volume Measurement: A "Kidney Stone Calculator" Study

BACKGROUND

An accurate estimation of the stone burden is the key factor for predicting retrograde intra-renal surgical outcomes. Volumetric calculations better stratify stone burden than linear measurements. We developed a free software to assess the stone volume and estimate the lithotrity duration according to 3D-segmented stone volumes, namely the Kidney Stone Calculator (KSC). The present study aimed to validate the KSC's reproducibility in clinical cases evaluating its inter-observer and intra-observer correlations.

METHODS

Fifty patients that harbored renal stones were retrospectively selected from a prospective cohort. For each patient, three urologists with different experience levels in stone management made five measurements of the stone volume on non-contrast-enhanced computed tomography (NCCT) images using the KSC.

RESULTS

the overall inter-observer correlation (Kendall's concordance coefficient) was 0.99 (p < 0.0001). All three paired analyses of the inter-observer reproducibility were superior to 0.8. The intra-observer variation coefficients varied from 4% to 6%, and Kendall's intra-observer concordance coefficient was found to be superior to 0.98 (p < 0.0001) for each participant. Subgroup analyses showed that the segmentation of complex stones seems to be less reproductible.

CONCLUSIONS

The Kidney Stone Calculator is a reliable tool for the stone burden estimation. Its extension for calculating the lithotrity duration is of major interest and could help the practitioner in surgical planning.

Validation of in vitro-produced and freeze-dried whole cell lysate antigens for ELISA Trypanosoma evansi antibody detection in camels

Trypanosoma evansi is a blood parasite responsible for surra in mammals, with a high impact in camels and horses. The WOAH-recommended reference method for detecting immunoglobulin G directed against T. evansi is ELISA, using whole cell lysate antigens (WCLAs). WCLAs are prepared with T. evansi produced in laboratory rodents, separated from blood cells using DE-cellulose anion exchange chromatography. As parasite lysates are fragile, antigens are preserved frozen pending use. For these reasons and others, T. evansi WCLAs are not commercially available. They are produced in small quantities, in a limited number of specialized laboratories, and they require a reliable and expensive cold chain for their shipment. In this study, we assessed and validated in vitro production of T. evansi and lyophilization of WCLAs in comparison with the reference method using frozen WCLAs prepared with parasites produced in rodents. Using a set of 400 samples monthly collected from 12 naturally infected camels followed-up for 1384 days, and two batches of referenced serum samples (infected, n = 12; non-infected, n = 15), statistical studies on qualitative and semi-quantitative results of the ELISAs did not show any significant difference when comparing the four combinations of parasites produced in vivo or in vitro, and frozen or freeze-dried WCLSAs. A repeatability study (28 repeats in 9 serum samples) was fully satisfying (p-value = 0.055). With the more convenient in vitro-produced freeze-dried WCLAs it was possible to: (i) avoid the ethical concern of in vivo production, (ii) improve the standardization of antigen production, (iii) secure antigen preservation during shipment and (iv) save a considerable amount of money (DE52-cellulose and dry-ice cold chain being avoided). Additional studies with other Trypanosoma spp are required for further extending ELISA to regional laboratories in enzootic areas, especially in view of the current progress in the "Progressive Control Pathway" (PCP) for trypanosomes in Africa.

Toe Pressure Measurements in Patients Suspected of Critical Limb Ischemia

An objective hemodynamic assessment is mandatory to confirm Critical Limb Ischemia (CLI). Toe pressure measurement is recommended. We compared toe measurements obtained using the Laser Doppler method (LD) (PERIMED PeriFlux, Sweden) considered as the reference test, with those obtained with a portable device using photoplethysmography (PPG) (Sys Toe Atys Medical, France). A total of 93 (123 legs) patients from 3 French hospitals with a clinical suspicion of CLI were included and had measurements with each device carried out by skilled operators. PPG was unable to provide a measurement in 10 patients. Lin's Coefficient correlation concordance (CCC) and Bland and Altman's scatter plot were analyzed for the 83 remaining patients, CCC was .84 95%CI (.77-.89). For detection of CLI, Cohen's kappa was .67 95%CI (.53-.81). The PPG device is fairly reliable for toe pressure measurement in patients suspected of CLI and could be useful when LD is not available. However, it fails to deliver a measurement in approximately 10% of cases. No conclusion should be made about CLI for these patients when no measurement is obtainable and other methods should be used (LD, transcutaneous oxygen pressure) to assess perfusion of the limbs.

Concordances and correlations between chronological, dental and bone ages: A retrospective study in French individuals

Bone and dental maturations are subject to physiological, environmental and pathological variables and are unique to each individual. Numerous methods for age estimation appeared to answer a new demand explained by the contemporary migratory movements and the increase of the crime rates. The objective of this study was to observe the relationships between skeletal and dental maturation stages to estimate which methods can be applied to a French population. This retrospective study was based on panoramic and cephalometric radiographs belonging to 192 (101 females and 91 males) orthodontic patients aged between 9 and 19 years, inhabitants of the Provence-Alpes-Côte d'Azur region. The Demirjian method based on dental calcification was used to estimate dental age. For the assessment of skeletal maturity and bone age, the Cervical Vertebral Maturation (CVM) method (Baccetti et al.) and its computerized version (Decocq et al.) were used. Spearman's correlation tests were performed to estimate the correlation between dental calcification stages and those of cervical vertebral maturation among the study population. The methods of Lin's concordance correlation coefficient and Bland and Altman were used to analyze the concordance between bone, dental and chronological ages. A moderate but statistically significant correlation was obtained between dental and skeletal developmental stages (R = 0.383-0.618). The tooth showing the highest correlation with vertebral stages was the second molar for both sexes. Earlier vertebral maturation stage affiliation was observed in girls. The results confirmed that bone and dental maturations can be assessed to estimate relevant biological ages for children in orthodontic or forensic contexts.

Measurement of capillary refill time with a handheld prototype device: a comparative validation study in healthy volunteers

Validity and reproducibility of clinical capillary refill time (CRT) measurement depend on many factors in daily routine practice. We conducted a prospective validation study of an automatized handheld prototype device providing standardized CRT assessment (DiCART™) in 20 healthy volunteers. Three different methods of CRT measurement were compared before and during dynamic circulatory changes induced by venous and arterial occlusion tests at both upper and lower limb levels: CRT_CLIN corresponding to basic clinical assessment and considered as the reference method; CRT_VIDEO corresponding to off-line videos reviewed by investigators recorded by DiCART™; and CRT_DiCART corresponding to on-line videos analysed by a built-in proprietary mathematical algorithm included in DiCART™. Five subjects were excluded because of a DiCART™ dysfunction. ROC_AUC to detect arterial occlusion test changes at the upper limb level were 1.00 (95%CI 1.00; 1.00), 0.96 (95%CI 0.88; 1.00), and 0.92 (95%CI 0.79; 1.00) for CRT_CLIN, CRT_VIDEO, and CRT_DiCART, respectively. Precision of CRT_CLIN and CRT_VIDEO were significantly better than CRT_DiCART (0.18 and 0.20 vs. 0.28; P < 0.05). Percentages of error were 76% and 87% for CRT_VIDEO and CRT_DiCART, respectively. DiCART™ had an excellent discrimination to detect major changes in CRT induced by arterial ischemia. However, the perfectible precision, the poor agreement with clinical assessment and numerous device dysfunctions give leads to the development of a further version of the prototype before promoting its use in clinical practice.Trial registration clinicaltrial.gov. Identifier: NCT04538612.

The old becomes new: advances in imaging techniques to assess nephron mass in children

Renal imaging is widely used in the assessment of surrogate markers of nephron mass correlated to renal function. Autopsy studies have tested the validity of various imaging modalities in accurately estimating "true" nephron mass. However, in vivo assessment of nephron mass has been largely limited to kidney volume determination by ultrasonography (US) in pediatric populations. Practical limitations and risks create challenges in incorporating more precise 3D volumetric imaging, like magnetic resonance imaging (MRI), and computed tomography (CT) technologies, compared to US for routine kidney volume assessment in children. Additionally, accounting for structural anomalies such as hydronephrosis when estimating renal parenchymal area in congenital anomalies of the kidney and urinary tract (CAKUT) is important, as it correlates with chronic kidney disease (CKD) progression. 3D imaging using CT and MRI has been shown to be superior to US, which has traditionally relied on 2D measurements to estimate kidney volume using the ellipsoid calculation. Recent innovations using 3D and contrast-enhanced US (CEUS) provide improved accuracy with low risk. Indexing kidney volume to body surface area in children is an important standard that may allow early detection of CKD progression in high-risk populations. This review highlights current understanding of various imaging modalities in assessing nephron mass, discusses applications and limitations, and describes recent advances in the field of imaging and kidney disease. Although renal imaging has been a long-standing, essential tool in assessing kidney disease, innovation and new applications of established technologies provide important tools in the study and management of kidney disease in children.

Fast and Selective Ablation of Liver Tumors by High-Intensity Focused Ultrasound Using a Toroidal Transducer Guided by Ultrasound Imaging: The Results of Animal Experiments

This study demonstrated that high-intensity focused ultrasound (HIFU) produced with an intra-operative toroidal-shaped transducer causes fast, selective liver tumor ablations in an animal model. The HIFU device is composed of 256 emitters working at 3 MHz. A 7.5 MHz ultrasound imaging probe centered on the HIFU transducer guided treatment. VX2 tumor segments (25 mg) were implanted into the right lateral liver lobes of 45 New Zealand rabbits. The animals were evenly divided into groups 1 (toroidal HIFU ablation), 2 (surgical resection) and 3 (untreated control). Therapeutic responses were evaluated with gross pathology and histology 11 d post-treatment. Toroidal transducer-produced HIFU ablation (average ablation rate 10.5 cc/min) allowed fast and homogeneous tumor treatment. Sonograms showed all ablations. VX2 tumors were completely coagulated and surrounded by safety margins without surrounding-organ secondary HIFU lesions. HIFU group tumor volumes at autopsy (39 mm³) were significantly lower than control group volumes (2610 mm³, p < 0.0001). HIFU group tumor metastasis (27%) was lower than resected (33%) and control (67%) group metastasis. Ultrasound imaging, gross pathology and histology results supported these outcomes. HIFU procedures had no complications. Rabbit liver tumor ablation using a toroidal HIFU transducer under ultrasound imaging guidance might therefore be an effective intra-operative treatment for localized liver metastases.

Assessment of four different cardiac softwares for evaluation of LVEF with CZT-SPECT vs CMR in 48 patients with recent STEMI

PURPOSE

To compare, vs CMR, four softwares: quantitative gated SPECT (QGS), myometrix (MX), corridor 4DM (4DM), and Emory toolbox (ECTb) to evaluate left ventricular ejection fraction (LVEF), end-systolic (ESV), and end-diastolic volumes (EDVs) by gated MPI CZT-SPECT.

METHODS

48 patients underwent MPI CZT-SPECT and CMR 6 weeks after STEMI, LV parameters were measured with four softwares at MPI CZT-SPECT vs CMR. We evaluated (i) concordance and correlation between MPI CZT-SPECT and CMR, (ii) concordance MPI CZT-SPECT/CMR for the categorical evaluation of the left ventricular dysfunction, and (iii) impacts of perfusion defects > 3 segments on concordance.

RESULTS

LVEF: LCC QGS/CMR = 0.81 [+ 2.2% (± 18%)], LCC MX/CMR = 0.83 [+ 1% (± 17.5%)], LCC 4DM/CMR = 0.73 [+ 3.9% (± 21%)], LCC ECTb/CMR = 0.69 [+ 6.6% (± 21.1%)]. ESV: LCC QGS/CMR = 0.90 [- 8 mL (± 40 mL)], LCC MX/CMR = 0.90 [- 9 mL (± 36 mL)], LCC 4DM/CMR = 0.89 [+ 4 mL (± 45 mL)], LCC ECTb/CMR = 0.87 [- 3 mL (± 45 mL)]. EDV: LCC QGS/CMR = 0.70 [- 16 mL (± 67 mL)], LCC MX/CMR = 0.68 [- 21 mL (± 63 mL], LCC 4DM/CMR = 0.72 [+ 9 mL (± 73 mL)], LCC ECTb/CMR = 0.69 [+ 10 mL (± 70 mL)].

CONCLUSION

QGS and MX were the two best-performing softwares to evaluate LVEF after recent STEMI.

Study of the growth and shape of the brain and cranial base during the first two years of life

Ontogeny of the cranial base and the brain integrates data on growth, maturation and ontogenetic allometry of these two systems in the course of development. The aim of our work was to study the ontogeny of the cranial base and the brain in order to understand their growth dynamic and shape changes using a traditional morphometric approach in individuals with normal (non-pathological) development.

MATERIEL AND METHOD

Forty-seven infants having been included in the unexpected infant death french protocol were analyzed. Medical imaging (CT and MRI) exams, followed by an autopsy and pathology examination allowed us to include only infants free from brain disease or pathology affecting growth.

RESULTS

Testing of measurement reliability validated 12 distances and 3 angles as well as the positioning of the landmarks that had been used to obtain the distances and the angles. No correlation between sex and the various variables studied was found. However, a correlation was observed between these variables and age, making it possible to propose a growth curve. A medium to strong correlation was found between brain variables and the bone variables of the cranial base, underlining the parallel development of the two systems.

CONCLUSION

Our study, carried out in a rigorously selected population of infants, presents a fundamental approach to the study of ontogenesis.

Comparison of perfused volume segmentation between cone-beam CT and 99mTc-MAA SPECT/CT for treatment dosimetry before selective internal radiation therapy using 90Y-glass microspheres

PURPOSE

To compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus ^99mTc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using ⁹⁰Y-glass microspheres.

MATERIALS AND METHODS

Fifteen patients (8 men, 7 women) with a mean age of 68.3±10.5 (SD) years (range: 47-82 years) who underwent a total of 17 SIRT procedures using ⁹⁰Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from ^99mTc-MAA SPECT/CT using either CBCT or ^99mTc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using ⁹⁰Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (D_T), non-tumoral liver, perfused liver (D_PL) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρ_c values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland-Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing-Bablok regression.

RESULTS

The intra- and interobserver reliabilities were good-to-excellent (ρ_c: 0.80-0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8Gy (IQR: -12.7; 16.1) and 5.6Gy (IQR: -13.6; 10.2) for D_PL-CBCT and D_PL-^99mTc-MAA SPECT/CT, respectively. The median differences were 1.6Gy (IQR: -29; 7.53) and 9.8Gy (IQR: -28.4; 19.9) for D_T-CBCT and D_T-^99mTc-MAA SPECT/CT respectively. Passing-Bablok regression analysis showed that both CBCT and ^99mTc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate D_T and D_PL at higher post-treatment doses.

CONCLUSION

CBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of ^99mTc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers.

Impact of volume calculation formulae on volume estimation accuracy of different shaped objects: an in vitro ultrasound and CT study

BACKGROUND

In image-assisted volume estimation, the volume of the object is calculated with a formula, using linear measurements of the objects. Since the volume estimation accuracy is thought to be influenced by the shape of the object, the volume estimation error would be related to the calculation formula used.

PURPOSE

To evaluate the volume estimation accuracy of selected volume calculation formulae, for different shaped objects.

MATERIAL AND METHODS

Globular (n = 5), elongated (n = 5), and near-spherical shaped plastic objects (n = 5), filled with water were subjected to ultrasound (US) and computed tomography (CT) in February 2018, to obtain the length, width, depth, and estimated volumes (EV). The volume was calculated manually using prolate, ellipsoid, and Lambert formulae. The actual volume (AV), EV, and calculated volumes were compared.

RESULTS

The AV was in the range of 10-445 mL. The reliability of measurements was high as assessed by the intra-class variability (Cronbach's alpha = 0.992). The EV has shown a high correlation to AV (US: ρ = 0.914, P < 0.001; CT: ρ = 0.943, P < 0.001; ellipsoid: ρ = 0.876, P < 0.001; prolate: ρ = 0.891, P < 0.001; Lambert: ρ = 0.876, P < 0.001). Regardless of the shape, the highest and lowest estimation accuracies were reported for prolate (bias = -0.7) and Lambert formulae (bias = +23.3), respectively. By any method, the globular objects were estimated with the highest accuracy: (US [bias = -0.31]; CT [bias = -0.14]; ellipsoid [bias = -1.5]; prolate [bias = -0.7]; Lambert [bias = 32.9]); and elongated objects were estimated with the lowest accuracy: (US [bias = -17.5]; CT [bias = -32.6]; ellipsoid [bias = -18.4]; prolate [bias = -0.3]; Lambert [bias = 11.4]).

CONCLUSION

The shape of the object and the calculation formula used has an impact on the volume estimation accuracy.

Renal Volume Estimation Using Freehand Ultrasound Scans: An Ex Vivo Demonstration

Renal volume has the potential to serve as a robust biomarker for tracking the onset and progression of renal diseases and also for quantifying renal function. We propose a method to estimate renal volumes using freehand ultrasound scans at the point of care. A conventional ultrasound probe was augmented with an Intel RealSense D435 i camera. Visual inertial simultaneous localization and mapping was used to localize the probe in free space. The acquired 2-D ultrasound images, segmented by trained clinicians, were combined with the estimated poses of the probe to yield accurate volumes. The method was tested on two ex vivo sheep kidneys embedded in gelatin phantoms. Four different scanning protocols were tested: transverse linear, transverse fan, longitudinal linear and longitudinal fan. The estimated renal volumes were compared with those obtained using the water displacement method, the ellipsoidal method and computed tomography imaging. The water displacement method yielded mean volumes of 66.00 and 66.20 mL for kidneys 1 and 2, respectively (ground truth). Freehand ultrasound scans produced mean volumes of 64.08 mL (2.90% error) and 65.25 mL (1.40% error); the ellipsoidal method yielded volumes of 57.49 mL (12.90% error) and 60.15 mL (9.13% error); and computed tomography yielded a volume of 63.00 mL (4.54% error).

Using histomorphometry for human and nonhuman distinction: A test of four methods on fresh and archaeological fragmented bones

Positive identification of human remains is the very first step in anthropological analysis, and the task may be particularly difficult in the case of fragmented bones. Histomorphometry methods have been developed to discriminate human from nonhuman bones, based on differences in the size and shape of Haversian systems between the two groups. Those methods all focus on a very specific type of bone, section, and zone. Therefore, the objective of this study was to test the efficiency of four histomorphometric methods on a sample of fragmented bones. The sample is composed of 37 archaeological and fresh specimens, 25 nonhumans (Bos taurus, Equus caballus, Sus scrofa, Capreolus, Canis familiaris, Cervus elaphus, Ovis, and Capra) and 12 humans (Homo sapiens). Eight histomorphometric criteria were collected from all intact osteons visible on each fragment and then inserted into the corresponding discriminate function of each method. The results were compared with the real origin to establish rates of correct classification for each method. The methods of Martiniaková et al. (2006) and Crescimanno and Stout (2012) obtained very low percentages of good classification (32 % and 67 %). Those of Cattaneo et al. (1999) obtained 94 % correct classification, but only after a correction of the units of measurement for Haversian canal area in their formula. The methods of Dominguez and Crowder (2012) obtained an 86 % rate for well-classified specimens. Some of the methods tested here contain errors in the original publication that make them unusable in their current state. Plus, it seems that histomorphometric methods developed from specific areas are more difficult to apply to fragments. A reduced number of intact osteons analyzed may partially affect the reliability of the method by being unrepresentative of the entire microstructure. Therefore, this study demonstrates that one should be cautious with the use of histomorphometric methods to distinguish human and nonhuman fragmented bone until further research can refine these methods to achieve greater reliability.

Impaired training-induced angiogenesis process with loss of pericyte-endothelium interactions is associated with an abnormal capillary remodelling in the skeletal muscle of COPD patients

Abstract

Chronic obstructive pulmonary disease (COPD) is associated with exercise intolerance and limits the functional gains in response to exercise training in patients compared to sedentary healthy subjects (SHS). The blunted skeletal muscle angiogenesis previously observed in COPD patients has been linked to these limited functional improvements, but its underlying mechanisms, as well as the potential role of oxidative stress, remain poorly understood. Therefore, we compared ultrastructural indexes of angiogenic process and capillary remodelling by transmission electron microscopy in 9 COPD patients and 7 SHS after 6 weeks of individualized moderate-intensity endurance training. We also assessed oxidative stress by plasma-free and esterified isoprostane (F₂-IsoP) levels in both groups. We observed a capillary basement membrane thickening in COPD patients only (p = 0.008) and abnormal variations of endothelial nucleus density in response to exercise training in these patients when compared to SHS (p = 0.042). COPD patients had significantly fewer occurrences of pericyte/endothelium interdigitations, a morphologic marker of capillary maturation, than SHS (p = 0.014), and significantly higher levels of F₂-IsoP (p = 0.048). Last, the changes in pericyte/endothelium interdigitations and F₂-IsoP levels in response to exercise training were negatively correlated (r = − 0.62, p = 0.025). This study is the first to show abnormal capillary remodelling and to reveal impairments during the whole process of angiogenesis (capillary creation and maturation) in COPD patients.

Trial registration

NCT01183039 & NCT01183052, both registered 7 August 2010 (retrospectively registered).

Role of three dimensional transesophageal echocardiography in predicting mitral regurgitation after percutaneous balloon mitral valvuloplasty

BACKGROUND

Percutaneous balloon mitral valvuloplasty (PBMV) can be complicated with significant mitral regurgitation (MR). We performed a pilot, prospective study to evaluate the role of three dimensional transesophageal echocardiography (3D-TEE) in the prediction of MR after PBMV through mitral valve quantification (MVQ).

METHODS

Between October 2014 and October 2016, 37 patients with rheumatic, moderate-to-severe mitral stenosis, referred to the Cath lab of Bab Alshearia University hospitals for PBMV, were divided into two age and sex matched groups. Group I included 25 patients without significant MR following PBMV [vena contract area (VCA) <0.4cm2], while group II included 12 patients with significant MR after PBMV [VCA ≥0.4cm2]. Both groups were comparable in terms of TEE data, Wilkins score for favorability of PBMV and baseline hemodynamics.

RESULTS

Data from MVQ showed that both groups were comparable (p>0.05) in terms of MV annulus quantification (Anteroposterior diameter, annular sphericity, 3D area and height), MV scallops (A1, A2, A3, P1, P2 and P3) areas, as well as A1 and A2 tenting volumes. However, we recorded significant differences between the two groups as regard total MV, A2, P2 and P3 tenting volumes (p<0.05) and tenting height (p=0.03), as well as A2, A3 and P2 prolapse volumes (p<0.05). Moreover, our data showed a significant difference between both groups in terms of MV coaptation heights (p=0.01), but not in anterior coaptation length (p=0.13).

CONCLUSION

Mitral valve quantification through 3D-TEE is a simple automated method, easily applicable to patients before PBMV. Moreover, MVQ-derived data, such as MV scallops' tenting and prolapse volumes, coaptation heights, and exposed and total A2 lengths may predict the possibility of significant MR after PBMV.

Size-dependent Tumor Response to Photodynamic Therapy and Irinotecan Monotherapies Revealed by Longitudinal Ultrasound Monitoring in an Orthotopic Pancreatic Cancer Model

Longitudinal monitoring of tumor size in vivo can provide important biological information about disease progression and treatment efficacy that is not captured by other modes of quantification. Ultrasound enables high-throughput evaluation of orthotopic mouse models via fast acquisition of three-dimensional tumor images and calculation of volume with a reasonable degree of accuracy. Herein, we compare orthotopic pancreatic tumor volume measurements determined by ultrasound with volume measured by calipers and tumor weight, and found strong correlations between the three modalities over a large range of tumor sizes, suggesting ultrasound can accurately quantify tumor volumes in this model. Furthermore, we demonstrate the unique ability of longitudinal treatment monitoring to reveal a tumor size-dependent response to Benzoporphyrin Derivative photodynamic therapy (BPD-PDT) and irinotecan. Small tumors (5-35 mm³ ) were found to respond well to a single round of PDT, while large tumors (35-65 mm³ ) showed no response to the same treatment. These results highlight the role that tumor size can play in preclinical interpretation of treatment response and more generally suggest that careful evaluation of subtle biological features such as this must be carefully considered in order to grant a more comprehensive understanding of disease biology in vivo.

Comparison of body composition assessment by DXA and BIA according to the body mass index: A retrospective study on 3655 measures

BACKGROUND AND AIMS

Body composition assessment is often used in clinical practice for nutritional evaluation and monitoring. The standard method, dual-energy X-ray absorptiometry (DXA), is hardly feasible in routine clinical practice contrary to Bioelectrical Impedance Analysis (BIA) method. We thus aimed to compare body composition assessment by DXA and BIA according to the body mass index (BMI) in a large cohort.

METHODS

Retrospectively, we analysed DXA and BIA measures in patients followed in a Nutrition Unit from 2010 to 2016. Body composition was assessed under standardized conditions in the morning, after a fasting period of 12 h, by DXA (Lunar Prodigy Advance) and BIA (Bodystat QuadScan 4000, Manufacturer's equation). Bland-Altman test was performed for each class of BMI (kg/m2) and fat mass and fat free mass values were compared using Kruskal-Wallis test. Pearson correlations were also performed and the concordance coefficient of Lin was calculated.

RESULTS

Whatever the BMI, BIA and DXA methods reported higher concordance for values of FM than FFM. Body composition values were very closed for patients with BMI between 16 and 18,5 (difference < 1kg). For BMI > 18,5 and BMI < 40, BIA overestimated fat free mass from 3,38 to 8,28 kg, and underestimated fat mass from 2,51 to 5,67 kg compared with DXA method. For BMI ≥ 40, differences vary with BMI. For BMI < 16, BIA underestimated fat free mass by 2,25 kg, and overestimated fat mass by 2,57 kg. However, limits of agreement were very large either for FM and FFM values, irrespective of BMI.

CONCLUSION

The small bias, particularly in patients with BMI between 16 and 18, suggests that BIA and DXA methods are interchangeable at a population level. However, concordance between BIA and DXA methods at the individual level is lacking, irrespective of BMI.

Establishment of reference values of the caudal vena cava by fast-ultrasonography through different views in healthy dogs

BACKGROUND

Clinical assessment of intravascular volume status is challenging. In humans, ultrasonographic assessment of the inferior vena cava diameter, directly or as a ratio to the aortic diameter is used to estimate intravascular volume status.

OBJECTIVES

To ultrasonographically obtain reference values (RV) for caudal vena cava diameter (CVCD ), area (CVCa ) and aortic ratios using 3 views in awake healthy dogs.

ANIMALS

One hundred and twenty-six healthy adult dogs from clients, students, faculty, or staff.

METHODS

Prospective, multicenter, observational study. Two observer pairs evaluated CVCD by a longitudinal subxiphoid view (SV), a transverse 11th-13th right hepatic intercostal view (HV), and a longitudinal right paralumbar view (PV). Inter-rater agreements were estimated using concordance correlation coefficients (CCC). For body weight (BW)-dependent variables, RVs were calculated using allometric scaling for variables with a CCC ≥ 0.7.

RESULTS

The CCC was ≤0.43 for the CVC/aorta ratio at the PV and ≤0.43 in both inspiration and expiration for CVC at the SV. The RVs using allometric scaling for CVCa at the HV for inspiration, expiration, and for CVCD at the PV were 6.16 × BW0.762 , 7.24 × BW0.787 , 2.79 × BW0.390 , respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

The CVCD , measured at the HV and PV in healthy awake dogs of various breeds has good inter-rater agreement suggesting these sites are reliable in measuring CVCD . Established RVs for CVCD for these sites need further comparison to results obtained in hypovolemic and hypervolemic dogs to determine their usefulness to evaluate volume status in dogs.

Validation study of 3D-printed anatomical models using 2 PLA printers for preoperative planning in trauma surgery, a human cadaver study

INTRODUCTION

3D printing contributes to a better understanding of the surgical approach, reduction and fixation of complex fractures. It is unclear how a 3D-printed model relates to a human bone. The accuracy of 3D-printed models is important to pre-bend plates and fit of surgical guides. We conduct a validation study in which we compare human cadavers with 3D-printed models to test the accuracy of 3D printing.

METHODS

Nine specimens were scanned, volume rendered into 3D reconstructions and saved as STL data. All models were in a ratio of 1:1 printed on the Ultimaker 3 and Makerbot Replicator Z18. Two independent observers measured all distances between the K-wires on the human cadavers, 2DCT, 3D reconstruction, Meshlab and both printers. A paired Samples T test was used to compare the measurements between the different modalities.

RESULTS

The least decrease in average distance in millimetres was seen in "the 3D printed pelvis 1", - 0.3 and - 0.8% on respectively the Ultimaker and Makerbot when compared with cadaver Pelvis (1) The 3D model of "Hand 2" showed the most decrease, - 2.5 and - 3.2% on the Ultimaker and Makerbot when compared with cadaver hand (2) Most significant differences in measurements were found in the conversion from 3D file into a 3D print and between the cadaver and 3D-printed model from the Makerbot.

CONCLUSION

Our 3D printing process results in accurate models suitable for preoperative workup. The Ultimaker 3 is slightly more accurate than the Makerbot Replicator Z18. We advise that medical professionals should perform a study that tests the accuracy of their 3D printing process before using the 3D-printed models in medical practice.

The prevalence and significance of renal perfusion defects in early kidney transplants quantified using 3D contrast enhanced ultrasound (CEUS)

OBJECTIVES

Vascular complications are one of the most common causes of early kidney transplant dysfunction. Contrast enhanced ultrasound increases sensitivity to vascular changes. The aim of this study was to assess the prevalence and size of vascular abnormalities in early renal transplants using 3D CEUS and the significance of perfusion defects on renal function.

METHODS

Ninety-nine renal transplant patients underwent 3D CEUS after surgery to quantify perfusion defects as percentage total renal volume (TRV). Serum creatinine and estimated glomerular filtration rate (eGFR) were recorded up to 3 months post-surgery.

RESULTS

Twenty participants had focal perfusion defects (0.2-43%TRV). There was a meaningful difference in patients with perfusion defects in eGFR at 1 month (90% CI 2.7-19.2 mL/min/1.73 m²) and 3 months (90% CI 1.9-19.6 mL/min/1.73 m²) and creatinine at 3 months (90% CI -56 - -8 μmol/L) using a predetermined clinical threshold. Perfusion defect size correlated well with both serum creatinine and eGFR at 3 months (R = 0.80, p ≤ 0.000 and 0.58, p = 0.038). No correlation was seen prior to 3 months.

CONCLUSIONS

Perfusion defects in kidney transplants were more common than expected and were highly likely to reduce renal function at 1-3 months, and the size of the defect affected the degree of functional change at 3 months.

KEY POINTS

• Perfusion defects were more common than previously thought. • Perfusion defects could be quantified using 3D CEUS. • The presence of even small perfusion defects may affect kidney function. • Size of perfusion defects correlated with subsequent kidney function at 3 months. • Potentially useful in informing clinician expectations of kidney function post-surgery.

Effect of various environments and computed tomography scanning parameters on renal volume measurements in vitro: A phantom study

Kidney volume is an important parameter in clinical practice, and accurate assessment of kidney volume is vital. The aim of the present study was to evaluate the effect of various environments, tube voltages, tube currents and slice thicknesses on the accuracy of a novel segmentation software in determining renal volume on computed tomography (CT) images. The volumes of potatoes and porcine kidneys were measured on CT images and compared with the actual volumes, which were determined by a water displacement method. CT scans were performed under various situations, including different environments (air or oil); tube voltages/tube currents (80 kVp/200 mAs, 120 kVp/200 mAs, 120 kVp/100 mAs); and reconstructed slice thicknesses (0.75 or 1.5 mm). Percentage errors (PEs) relative to the reference standards were calculated. In addition, attenuation and image noise under different CT scanning parameters were compared. Student's t-test was also used to analyze the effect of various conditions on image quality and volume measurements. The results indicated that the volumes measured in oil were closer to the actual volumes (P<0.05). Furthermore, attenuation and image noise significantly increased when using a tube voltage of 80 kVp, while the mean PEs between 120 and 80 kVp voltages were not significantly different. The mean PEs were greater when using a tube current of 100 mAs compared with a current of 200 mAs (P<0.05). In addition, the volumes measured on 1.5 mm slice thickness were closer to the actual volumes (P<0.05). In conclusion, different environments, tube currents and slice thicknesses may affect the volume measurements. In the present study, the most accurate volume measurements were obtained at 120 kVp/200 mAs and a slice thickness of 1.5 mm.

Ultrasonographic renal volume in Chinese children: Results of 1683 cases

BACKGROUND

At present, little information has been made available in the evaluation of renal volume in pediatric groups of different ages.

PURPOSE

The purposes of the study are to evaluate the relationship between anthropometric measurements and renal volume measured with three-dimensional ultrasonography in Chinese children who have normal kidneys, and to attempt to develop reliable reference values of renal volume to estimate the renal sizes.

METHODS

A total of 1572 Chinese Han children suffering from stomachache, cryptorchidism and neurogenic enuresis with no history of renal disease or pathological abnormalities that might affect measurements, aged 1month to 12years (mean, 5.64years) were examined bilateral kidneys by ultrasonography. The measurements of renal volume were determined using QLAB software in IU22 units (Philips Medical Systems, Holland). Anthropometric indices including sex, age, height and weight were collected for reviewed analysis.

RESULTS

A total of 1683 children were included, and renal volume of 1572 cases (93.4%) was accepted. There was no significant difference between renal volumes of male and female separately in left and right kidneys (P=0.844 and P=0.621, respectively), whereas there was a significant difference between mean left and right renal volumes (P=0.000). Age, height and weight were all significant correlations with renal volume (R(2), 0.885 and 0.913 for the left and right kidneys, respectively, both P=0.000), and age was the strongest correlation with renal volume (r, 0.472 and 0.399 for the left and right kidneys, respectively) among the anthropometric indices. We drew regression equations to estimate renal volume as follows: left renal volume (cm(3))=0.441×age+0.156×height+0.398×weight+6.677 and right renal volume (cm(3))=0.256×age+0.195×height+0.632×weight+1.788, and developed reference values of renal volume separately for the left and right kidneys in different age groups.

CONCLUSIONS

Regression equations have been developed, which define the renal volume from three-dimensional ultrasonography and may assist pediatricians in monitoring renal growth and detecting of unsuspected bilateral increases or decreases in renal size.

Reproducibility of renal volume measurement in adults using 3-dimensional sonography

OBJECTIVES

The purpose of this study was to determine the interobserver reproducibility of renal volume measurement performed by 3-dimensional (3D) sonography.

METHODS

We conducted an exploratory, quantitative, observational, and descriptive cross-sectional study. We calculated ranges, means, and standard deviations of the renal volumes obtained with 3D sonography by 2 different examiners from a sample of 30 patients. The interobserver reproducibility was assessed by calculating intraclass correlation coefficients (ICCs) and by construction of Bland-Altman plots.

RESULTS

The ICC between the right 3D renal volumes obtained by examiners 1 and 2 was 0.8552 (95% confidence interval, 0.7153-0.9292), showing excellent reproducibility (P < .0001). For the left 3D renal volumes obtained by examiners 1 and 2, the ICC was 0.6411 (95% confidence interval, 0.3652-0.8135), showing average to good reproducibility (P = .0001). The Bland-Altman plots showed mean differences ± SD of -4.8% ± 23.9% between the right renal volumes obtained by examiners 1 and 2 and -2.2% ± 38% between the left renal volumes. The 95% limits of agreement between the right renal volumes obtained by examiners 1 and 2 were -28.7% to 19%, whereas those between the left renal volumes were -40.2% to 35.7%.

CONCLUSIONS

Three-dimensional sonography showed good interobserver reproducibility, which was better for the right kidney. It appears necessary to establish standardized techniques for acquisition of sonographic renal volumes.

Equine hoof slip distance during trot at training speed: comparison between kinematic and accelerometric measurement techniques

Longitudinal sliding of horse's hooves at the beginning of stance can affect both performance and orthopaedic health. The objective of this study was to compare two measurement methods for quantifying hoof slip distances at training trot. The right front hoof of four French Trotters was equipped with an accelerometer (10 kHz) and kinematic markers. A firm wet sand track was equipped with a 50 m calibration corridor. A high-frequency camera (600 Hz) was mounted in a vehicle following each horse trotting at about 7 m/s. One of the horses was also trotted on raw dirt and harrowed dirt tracks. Longitudinal slip distance was calculated both from kinematic data, applying 2D direct linear transformation (2D-DLT) to the markers image coordinates, and from the double integration of the accelerometer signal. For each stride, both values were compared. The angle of the hoof with respect to the track was also measured. There was 'middling/satisfactory' agreement between accelerometric and 2D-DLT measurements for total slip and 'fairly good' agreement for hoof-flat slip. The influence of hoof rotation on total slip distance represented <6% of accelerometric measures. The differences between accelerometric and kinematic measures (from -0.5 cm to 2.1cm for total slip and from -0.2 cm to 1.4 cm for hoof-flat slip) were independent of slip distance magnitude. The accelerometric method was a simple method to measure hoof slip distances at a moderate training speed trot which may be useful to compare slip distances on various track surfaces.

Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: an upright, weightbearing MRI study

The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher's exact test, p<0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p<0.017). This study adds to our understanding of PF pain in two ways-(1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and (2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics.

Assessing renal parenchymal volume on unenhanced CT as a marker for predicting renal function in patients with chronic kidney disease

OBJECTIVES

To estimate renal volume in chronic kidney disease (CKD) patients using a semiautomated software and compare them with split renal function estimates from radionuclide renogram (RR). We proposed that renal volume from unenhanced computed tomography (CT) scans may serve as surrogate marker for assessing renal function in CKD patients.

MATERIALS AND METHODS

Unenhanced multidetector CT scans of 26 patients with CKD (estimated glomerular filtration rate [eGFR] <60 mL/kg/body surface area [BSA]) and 10 controls (eGFR >60 mL/kg/BSA) were analyzed to calculate renal volumes using a semiautomated software (AMIRAV5.2.0). Volumes obtained were then correlated with corresponding eGFR and split renal function estimates from RR. Volumes were also compared with those obtained on enhanced scans in 10 cases (five disease group, five controls). Bland-Altman analysis was used to assess agreement between methods.

RESULTS

A moderately positive correlation was found between renal volume obtained on unenhanced CT and eGFR (r = 0.65, P < .0001), whereas a significantly high correlation with split function estimates from RR (r = 0.95, P < .001) was found. Bland-Altman analysis revealed a good agreement between renal volume from CT and renal function from RR (34/36 observations were within 95% CI and there were two outliers). Correlation between volumes obtained from unenhanced and enhanced CT scans was also significant (r = 0.96).

CONCLUSION

In patients with CKD, renal volume derived from unenhanced CT can possibly serve as a surrogate marker for assessing and monitoring renal function reserves to plan further management.

Bifocals in children with Down syndrome (BiDS) - visual acuity, accommodation and early literacy skills

PURPOSE

Reduced accommodation is seen in children and young adults with Down syndrome (DS), yet providing bifocals has not become a routine clinical management. This study investigates the impact of bifocals on visual function, visual perceptual and early literacy skills in a group of school children with DS.

METHODS

  In this longitudinal study, each child was followed for 5months with single-vision (SV) lenses after which bifocals were prescribed if required, based on their accommodative response. Visual acuity (VA), accommodation, perceptual and literacy skills were measured after adaptation to bifocals and 5months later. Educational progress and compliance with spectacle wear were assessed through school and parental reports.

RESULTS

  Fourteen children and young adults with DS participated in the study. Eighty-five percent required bifocals with additions ranging from +1.00D to +3.50D. The mean near logMAR VA improved with bifocals (p=0.007) compared to SV lenses. Repeated measures anova showed that there was more accurate focus (less accommodative lag) through the bifocals (p=0.002), but no change in the accommodation exerted through the distance portion compared to SV lenses (p=0.423). There was a main effect of time on sight words (p=0.013), Word Identification (p=0.047), Visual Closure (p=0.006) and Visual Form Constancy (p=0.001).

CONCLUSION

Bifocals provide clearer near vision in DS children with reduced accommodation. This is shown by improved VA and decreased lag of accommodation. The results indicate that the improvement in VA results in improved scores in early literacy skills. Better compliance with bifocals over SV lenses was seen.

Are renal volumes measured by magnetic resonance imaging and three-dimensional ultrasound in the term neonate comparable?

Renal volume, but not renal length, has been shown to be positively correlated with renal function. Three-dimensional (3D) ultrasound and magnetic resonance imaging (MRI) are two modalities used to assess renal volume. The aim of our study was to determine whether 3D ultrasound measurements of renal volume in the neonate are comparable to those of MRI measurements. Preterm and term neonates had an MRI and 3D ultrasound to determine renal volume at the same time as they had an MRI brain scan for other clinical conditions. The preterm neonates were all term corrected age, and the term neonates were 1-4 weeks of age. None of the kidneys examined were abnormal. There were no significant differences in the weight or length of the preterm and term infants at the time of their MRI scan. The left renal length was significantly longer according to MRI measurements than according to 3D ultrasound measurements (p=0.02). Renal volumes of both the left and right kidney were greater when measured by MRI than by 3D ultrasound (p<0.0001, respectively). Total volumes of the kidneys were greater when measured by MRI than by 3D ultrasound (p=0.008). Renal volume in neonates was significantly less when evaluated by 3D ultrasound than by MRI. These results demonstrate that MRI and 3D ultrasound renal volumes are not comparable in the neonatal population and, therefore, the same radiological modality should be used if repeat volume measurements are to be performed.

Three-dimensional ultrasound imaging

This review is about the development of three-dimensional (3D) ultrasonic medical imaging, how it works, and where its future lies. It assumes knowledge of two-dimensional (2D) ultrasound, which is covered elsewhere in this issue. The three main ways in which 3D ultrasound may be acquired are described: the mechanically swept 3D probe, the 2D transducer array that can acquire intrinsically 3D data, and the freehand 3D ultrasound. This provides an appreciation of the constraints implicit in each of these approaches together with their strengths and weaknesses. Then some of the techniques that are used for processing the 3D data and the way this can lead to information of clinical value are discussed. A table is provided to show the range of clinical applications reported in the literature. Finally, the discussion relating to the technology and its clinical applications to explain why 3D ultrasound has been relatively slow to be adopted in routine clinics is drawn together and the issues that will govern its development in the future explored.

Relation between total renal volume and renal function: Usefulness of 3D sonographic measurements with a matrix array transducer

OBJECTIVE

The aims of this study were to evaluate the reproducibility of 3D sonography with a matrix array transducer as a means of measuring renal volume and to investigate correlations between renal volume and renal function.

SUBJECTS AND METHODS

One hundred twenty subjects (20 consecutively registered patients with one of the five stages of chronic renal disease and 20 healthy volunteers [stage 0 renal function]) were enrolled. Individual renal volume was determined by two independent observers using 2D sonographic and 3D matrix array transducer sonographic data. The reproducibility of volume measurement was evaluated for both of these methods. After total renal volume was normalized to body surface area, correlations between normalized total renal volume and estimated glomerular filtration rate (GFR) were evaluated. Differences in normalized total renal volume related to stage of renal function also were evaluated.

RESULTS

The reproducibility of 3D sonographic measurements obtained with a matrix array transducer was greater than that of 2D sonographic measurements. The correlation between normalized total renal volume obtained with matrix array transducer 3D sonography and estimated GFR for two observers (r = 0.809 and 0.813; p < 0.001) was better than that between normalized total renal volume obtained with 2D sonography and estimated GFR (r = 0.696 and 0.715; p < 0.001). The mean normalized total renal volumes obtained with matrix array transducer 3D sonography in stages 0 and 1 were significantly larger than those in other stages (p < 0.001). The mean normalized total renal volume in stage 5 disease was significantly smaller than the volumes in the other stages (p < 0.001).

CONCLUSION

Three-dimensional sonography with a matrix array transducer is a reliable means of measuring renal volume during evaluations of patients with reduced renal function.

Method comparison of automated matching software-assisted cone-beam CT and stereoscopic kilovoltage x-ray positional verification image-guided radiation therapy for head and neck cancer: a prospective analysis

We sought to characterize interchangeability and agreement between cone-beam computed tomography (CBCT) and digital stereoscopic kV x-ray (KVX) acquisition, two methods of isocenter positional verification currently used for IGRT of head and neck cancers (HNC). A cohort of 33 patients were near-simultaneously imaged by in-room KVX and CBCT. KVX and CBCT shifts were suggested using manufacturer software for the lateral (X), vertical (Y) and longitudinal (Z) dimensions. Intra-method repeatability, systematic and random error components were calculated for each imaging modality, as were recipe-based PTV expansion margins. Inter-method agreement in each axis was compared using limits of agreement (LOA) methodology, concordance analysis and orthogonal regression. 100 daily positional assessments were performed before daily therapy in 33 patients with head and neck cancer. Systematic error was greater for CBCT in all axes, with larger random error components in the Y- and Z-axis. Repeatability ranged from 9 to 14 mm for all axes, with CBCT showing greater repeatability in 2/3 axes. LOA showed paired shifts to agree 95% of the time within +/-11.3 mm in the X-axis, +/-9.4 mm in the Y-axis and +/-5.5 mm in the Z-axis. Concordance ranged from 'mediocre' to 'satisfactory'. Proportional bias was noted between paired X- and Z-axis measures, with a constant bias component in the Z-axis. Our data suggest non-negligible differences in software-derived CBCT and KVX image-guided directional shifts using formal method comparison statistics.

Usefulness of renal volume measurements obtained by a 3-dimensional sonographic transducer with matrix electronic arrays

OBJECTIVE

The purpose of this study was to examine the feasibility of 3-dimensional (3D) sonography using a matrix array transducer to measure renal volume.

METHODS

One hundred consecutive patients with a normal serum creatinine level and kidney appearance on computed tomography (CT) performed within 2 months before sonography were enrolled in this study. Two hundred individual renal volumes were blindly obtained by the ellipsoid formula, the stacked ellipse method, the voxel count method using routine 2-dimensional (2D) sonographic data, 3D sonographic data using a matrix array transducer, and CT data, respectively. The voxel count method was validated as the reference standard by the water displacement method in 10 cadaveric pig kidneys (r = 0.99; P < .001). Renal volumes determined by 2D and 3D sonography were compared with volumes determined by CT.

RESULTS

Volumes determined by 2D sonography were significantly lower than those determined by CT (P < .001) but similar to those determined by 3D sonography (P = .78). The percent volume error of 3D sonography (mean +/- SD, -2.2% +/- 3.7%) was significantly lower than that of 2D sonography (-15.7% +/- 11.8%) with CT as the standard (P < .001). The correlation coefficient between 3D sonography and CT (r = 0.98; P < .0001) was better than that between 2D sonography and CT (r = 0.83; P < .0001). In addition, Bland-Altman analysis revealed that the limits of agreement between 3D sonography and CT (-9.7% to 5.1%) were narrower than those between 2D sonography and CT (-45.6% to 9.8%).

CONCLUSIONS

Three-dimensional sonography with a matrix array transducer can significantly reduce renal volume measurement errors and offers a reliable means of determining renal volumes.

Kidney dimensions at sonography are correlated with glomerular filtration rate in renal transplant recipients and in kidney donors

The gold standard to assess renal function is the measurement of glomerular filtration rate (GFR). For practical reasons, renal function is often evaluated from serum creatinine (S Cr) or cystatin C (S Cys), and GFR is predicted from SCr. Ultrasound scanning of the kidneys is used only to evaluate renal morphology. The aim of this study was to evaluate the relationship between sonographic renal dimensions and GFR in renal transplant recipients and in kidney donors. GFR (urinary clearance of (99m)Tc-DTPA), S Cr, and S Cys were measured in 33 donors (28 females [F], 5 males [M]; SCr, 0.81-1.90 mg/dL) and 30 recipients (8 F, 22 M; SCr, 0.96-2.42 mg/dL). GFR was also predicted using the Cockcroft and Gault (CG) formula and with the simplified Modification of Diet in Renal Disease (MDRD) formula. Length, width, and depth of kidneys and renal sinus were measured using renal sonography. Among sonographic measurements, kidney length showed the best correlation with GFR. A closer correlation with GFR was found in donors (r = 0.639; P < .00007) than in recipients (r = 0.511; P < .005). In either case, the correlation of kidney length with GFR was greater than that of S Cr or S Cys, and similar to that of CG or MDRD GFR. Accuracy of kidney length as an indicator of GFR impairment was not statistically different from laboratory tests. Only in donors did CG show better accuracy. In conclusion, renal dimensions at sonography closely correlated with GFR. Thus, renal sonography can give information also on the function of the renal graft and of the remaining kidney of living donors.

The use of polyacrylamide gel in soft-tissue augmentation: an experimental assessment

BACKGROUND

An increasing number of soft-tissue filler substances that lack experimental and clinical data have been introduced into plastic surgery practice outside the United States. One of these substances is polyacrylamide gel. It contains 2.5% polyacrylamide and 97.5% water. It is homogenous and stable, and has optimum viscosity and elasticity.

METHODS

One milliliter of polyacrylamide gel was injected into the subcutaneous layer of the right ear in 28 rabbits. The rabbits were divided into two groups, according to when the material was harvested and evaluated. Material was harvested at 4 months in 15 rabbits and 7 months in 13 rabbits. Each group underwent volumetric ultrasound evaluation, magnetic resonance imaging, and histological evaluation with hematoxylin and eosin and CD68 staining.

RESULTS

Results were easily observed because of the superficial position of the injected material. There were no systemic or local complications. The samples harvested showed a clear and jelly-like consistency similar to that of the initially injected material. The volume was constant after 6 weeks, after an initial period of acute stretching. Ultrasound volumetric analysis was also constant in all groups. At 7 months, a stable volume of 1.0 +/- 0.2 ml was observed. Magnetic resonance imaging scanning showed that the material was stable and that there was no inflammatory reaction. Histological analysis revealed a minimal foreign-body reaction, and the injected material was occasionally surrounded by a thin collagen membrane. The material remained in place.

CONCLUSIONS

Polyacrylamide gel has a long-lasting effect, with minimal volume variation. It remains soft to the touch and in place.

Method comparison of ultrasound and kilovoltage x-ray fiducial marker imaging for prostate radiotherapy targeting

Several measurement techniques have been developed to address the capability for target volume reduction via target localization in image-guided radiotherapy; among these have been ultrasound (US) and fiducial marker (FM) software-assisted localization. In order to assess interchangeability between methods, US and FM localization were compared using established techniques for determination of agreement between measurement methods when a 'gold-standard' comparator does not exist, after performing both techniques daily on a sequential series of patients. At least 3 days prior to CT simulation, four gold seeds were placed within the prostate. FM software-assisted localization utilized the ExacTrac X-Ray 6D (BrainLab AG, Germany) kVp x-ray image acquisition system to determine prostate position; US prostate targeting was performed on each patient using the SonArray (Varian, Palo Alto, CA). Patients were aligned daily using laser alignment of skin marks. Directional shifts were then calculated by each respective system in the X, Y and Z dimensions before each daily treatment fraction, previous to any treatment or couch adjustment, as well as a composite vector of displacement. Directional shift agreement in each axis was compared using Altman-Bland limits of agreement, Lin's concordance coefficient with Partik's grading schema, and Deming orthogonal bias-weighted correlation methodology. 1,019 software-assisted shifts were suggested by US and FM in 39 patients. The 95% limits of agreement in X, Y and Z axes were +/-9.4 mm, +/-11.3 mm and +/-13.4, respectively. Three-dimensionally, measurements agreed within 13.4 mm in 95% of all paired measures. In all axes, concordance was graded as 'poor' or 'unacceptable'. Deming regression detected proportional bias in both directional axes and three-dimensional vectors. Our data suggest substantial differences between US and FM image-guided measures and subsequent suggested directional shifts. Analysis reveals that the vast majority of all individual US and FM directional measures may be expected to agree with each other within a range of 1-1.5 cm. Since neither system represents a gold standard, clinical judgment must dictate whether such a difference is of import. As IMRT protocols seek dose escalation and PTV reduction predicated on US- and FM-guided imaging, future studies are needed to address these potential clinically relevant issues regarding the interchangeability and accuracy of novel positional verification techniques. Comparison series with multiple image-guidance systems are needed to refine comparisons between targeting methods. However, we do not advocate interchangeability of US and FM localization methods.

Three-dimensional ultrasound volumetric measurements: is the largest number of image planes necessary for outlining the region-of-interest?

Volumetric measurement is useful in the clinical practice as it can accurately assess the size of organs and lesions, which aids diagnosis and monitoring of treatment response. This in vitro study was undertaken to evaluate and compare the accuracy of three-dimensional ultrasound (3D-US) volumetric measurements using different numbers of image planes for outlining the region-of-interest. A total of 20 tissue phantoms (10 with regular and 10 with irregular tissue specimens) with known volume (2.2 - 14.7 ml) were constructed. The tissue phantoms were scanned with a commercially-available ultrasound machine in conjunction with a 3D add-on system and the volume of the tissue specimen of the phantoms was measured by manual outlining of the boundaries using different numbers of image plane (16, eight, four and two image planes). Results showed that there was a high accuracy in 3D-US volumetric measurements, when 16 and eight image planes were used (best-fit slope between measured and true volume: 0.9224-0.9761 and 0.9099-0.956, respectively). Results also showed that there was no significant difference in the volume measured with 16 and eight image planes for both phantoms with regular- and irregular-shaped tissue specimens (p > 0.05). The measurement differences between 16 and eight image planes ranged from -0.07 to 0.14 ml for phantoms with regular-shaped tissue and from -0.24 to 0.1 ml for phantoms with irregular-shaped tissue. 3D-US has a high accuracy in volumetric measurements of regular- and irregular-shaped structures. Although highest accuracy in volume measurements was found when 16 image planes were used, similar level of accuracy can be achieved with eight image planes but the measurement time can be reduced by 50%. Therefore, in 3D-US volumetric measurements, the largest number of image planes may not be necessary for outlining the region-of-interest.

Accuracy of sonographic volume measurements of kidney transplant

PURPOSE

Sonographic measurement of renal volume is one of the parameters used in the diagnosis of renal transplant dysfunction and in follow-up of patients with renal transplant. The aim of this study was to compare the prolate ellipsoid formula with a new formula in calculating the volume of a transplanted kidney.

METHODS

The renal volumes in 24 patients with a stable renal transplant were determined sonographically with the ellipsoid formula and via helical CT with the voxel-count method, which is the gold standard. A new formula that uses renal length and the cross-sectional area at the maximum transverse section has been evaluated in a small series of transplanted kidneys.

RESULTS

Renal volume was underestimated with the sonographic ellipsoid formula and the new formula. The new formula yielded the lowest underestimation of the mean renal volume, and the measurements obtained with it were not significantly different from those obtained with CT.

CONCLUSIONS

The use of sonography is appropriate for accurate calculation of renal volume, and the new formula that uses only 2 ultrasound parameters best represents the volume of a renal transplant.

Volume estimation of small phantoms and rat kidneys using three-dimensional ultrasonography and a position sensor

To evaluate the accuracy of small volume estimation, both in vivo and in vitro, measurements with a three-dimensional (3D) ultrasound (US) system were carried out. A position sensor was used and the transmitting frequency was 10 MHz. Balloons with known volumes were scanned while rat kidneys were scanned in vivo and in vitro. The Archimedes' principle was used to estimate the true volume. For balloons, the 3D US system gave very good agreement with true volumes in the volume range 0.1 to 10.0 mL (r = 0.999, n = 45, mean difference +/- 2SD = 0.245 +/- 0.370 mL). For rat kidneys in vivo (volume range 0.6 to 2.7 mL) the method was less accurate (r = 0.800, n = 10, mean difference +/- 2SD = -0.288 +/- 0.676 mL). For rat kidneys in vitro (volume range 0.3 to 2.7 mL) the results showed good agreement (r = 0.981, n = 23, mean difference +/- 2SD = 0.039 +/- 0.254 mL). For balloons, kidneys in vivo and in vitro, the mean percentage error was 9.3 +/- 4.8%, -17.1 +/- 17.4%, and 4.6 +/- 11.5%, respectively. This method can estimate the volume of small phantoms and rat kidneys and opens new possibilities for volume measurements of small objects and the study of organ function in small animals. (E-mail ).