Ultrasound tissue characterization of the normal kidney

Introduction of the Grayscale Median for Ultrasound Tissue Characterization of the Transplanted Kidney

Ultrasound examination is advised for early post-kidney transplant assessment. Grayscale median (GSM) quantification is novel in the kidney transplant field, with no systematic assessment previously reported. In this prospective cohort study, we measured the post-operative GSM in a large cohort of adult kidney transplant recipients (KTR) who consecutively underwent Doppler ultrasound directly after transplantation (within 24 h), compared it with GSM in nontransplanted patients, and investigated its association with baseline and follow-up characteristics. B-mode images were used to calculate the GSM in KTR and compared with GSM data in nontransplanted patients, as simulated from summary statistics of the literature using a Mersenne twister algorithm. The association of GSM with baseline and 1-year follow-up characteristics were studied by means of linear regression analyses. In 282 KTR (54 ± 15 years old, 60% male), the median (IQR) GSM was 55 (45–69), ranging from 22 to 124 (coefficient of variation = 7.4%), without differences by type of donation (p = 0.28). GSM in KTR was significantly higher than in nontransplanted patients (p < 0.001), and associated with systolic blood pressure, history of cardiovascular disease, and donor age (std. β = 0.12, −0.20, and 0.13, respectively; p < 0.05 for all). Higher early post-kidney transplant GSM was not associated with 1-year post-kidney transplant function parameters (e.g., measured and estimated glomerular filtration rate). The data provided in this study could be used as first step for further research on the application of early postoperative ultrasound in KTR.

Proposal for computer-aided diagnosis based on ultrasound images of the kidney: is it possible to compare shades of gray among such images?

Objective

To compare ultrasound images of the kidney obtained, randomly or in a controlled manner (standardizing the physical aspects of the ultrasound system), by various professionals and with different devices.

Materials and Methods

We evaluated a total of 919 images of kidneys, obtained by five professionals using two types of ultrasound systems, in 24 patients. The images were categorized into four types, by how they were acquired and processed. We compared the gray-scale median and different gray-scale ranges representative of virtual histological tissues.

Results

There were statistically significant differences among the five professionals, regardless of the type of ultrasound system employed, in terms of the gray-scale medians for the images obtained (p < 2.2e-16). Analyzing the four categories of images-a totally random image (without any standardization); a standardized image (with fixed values for gain, time gain control, and dynamic range); a normalized version of the random image; and a normalized version of the standardized image-we determined that the random image, even after normalization, differed quite significantly among the professionals (p = 0.006098). The analysis of the normalized version of the standardized image did not differ significantly among the professionals (p = 0.7319).

Conclusion

Our findings indicate that a gray-scale analysis of ultrasound images of the kidney performs better when the image acquisition process is standardized and the images undergo a process of normalization.

Use of ultrasound imaging software to differentiate venous and lymphatic edema in lower limbs

BACKGROUND

Lower limb edema has both systemic and local causes. Using software to differentiate the origin of edema in ultrasound images is an innovation.

OBJECTIVE

To determine the parameters for using software to differentiate edema of venous and/or lymphatic origin in ultrasound images of the lower limbs.

METHOD

This is a cross-sectional, quantitative, analytical study with non-probabilistic sampling by convenience. Data were collected by patient interview, physical examination, ultrasound examination, and analysis of software for tissue characterization in ultrasound image by means of quantification of echogenicity and Gray Scale Median (GSM).

RESULTS

The sample comprised 42 lower limbs with venous edema, 35 with lymphatic edema, 14 with mixed edema, and 11 control limbs. The distributions of pixels in echogenicity intervals by group was as follows. In the venous edema group, 88.31% were distributed from hypoechogenic interval IV to echogenic interval III; in the lymphatic edema group 71.73% were from hypoechogenic interval II to echogenic interval I; in the mixed edema group 76.17% were from hypoechogenic interval III to echogenic interval II; and in the control group 84.87% were distributed from echogenic interval II to hyperechogenic interval I. Mean and standard deviation of GSM values showed statistical differences between groups.

CONCLUSION

The CATUS software enabled differentiation of the type of lower limb edema, facilitating diagnosis of edema type and, consequently, choice of the best therapeutic option.

Pantoprazole-induced acute kidney injury: A case report

The present study reports a case of pantoprazole-induced acute kidney disease. The patient was diagnosed with acute kidney injury with wide interstitial inflammation and eosinophil infiltration. Following 1 month of glucocorticoid therapy, the patient's serum creatinine and urea nitrogen decreased to within normal ranges. The presentation, clinical course, diagnosis and prognosis of pantoprazole-induced acute kidney injury are discussed herein to highlight the importance of early and correct diagnosis for good prognosis. Disease characteristics include short-term increased serum creatinine levels that respond to glucocorticoid treatment. The patient had no history of chronic kidney disease or proteinuria and presented with increased serum creatinine following treatment with pantoprazole. Following the end of pantoprazole treatment, short-term RRT and long-term prednisolone was administered, then serum creatinine returned to normal. Pantoprazole-induced acute kidney injury is commonly misdiagnosed and late diagnosis results in poor patient prognoses. Misdiagnosis leads to the administration of treatments that may exacerbate the condition, so appropriate diagnosis and treatment for pantoprazole-induced acute kidney injury is necessary.

Objective image analysis of real-time three-dimensional intraoperative ultrasound for intrinsic brain tumour surgery

Background

There is growing evidence that maximal surgical resection of primary intrinsic brain tumours is beneficial, both by improving progression free and overall survival and also by facilitating postoperative chemotherapy and radiotherapy. Hence, there has been an increase in the popularity of real-time intraoperative imaging in brain tumour surgery. The complex theatre arrangements, prohibitive cost and prolonged theatre time of intraoperative MRI have restricted its application. By comparison, intraoperative three-dimensional ultrasound (i3DUS) is user friendly, cost-effective and portable and adds little to surgical time. However, operator-dependent image quality and image interpretation remain limiting factors to the wider application of this technique. The aim of this study was to explore objective i3DUS image analysis and its potential therapeutic role in brain tumour surgery.

Methods

A prospective, observational study was undertaken (approved by the local Research and Ethics Committee prior to recruitment). Biopsies were taken from the solid, necrotic, periphery and brain/tumour interface of intrinsic primary brain tumours. Digital i3DUS images were analysed to extract quantitative parameters from these regions of interest (ROI) in the i3DUS images. These were then correlated with the histology of the relevant specimens. The histopathologist was blinded to the imaging findings.

Results

Ninety-seven patients (62 males; mean 54 years) with varying gliomas (84 high grade) were included. Two hundred and ninety regions of interest were analysed. Mean pixel brightness (MPB) and standard deviation (SD) were correlated with histological features. Close correlations were noted between MPB and cellularity, and SD and intrinsic cellular diversity.

Conclusions

MPB and SD are objective measures reflecting the sensitivity of i3DUS in detecting the presence and extent of intrinsic brain tumours. They indirectly suggest heterogeneity, cellularity and invasiveness, providing information of the nature of the tumour, and also reflect the sensitivity of intraoperative US to detect the presence of residual intrinsic brain tumours. Development of this paradigm will enhance i3DUS use as an adjunct in brain tumour surgery. Optimizing its intraoperative application will impact surgical resection and, hence, patient outcome.

Tissue characterization by photographic imaging during treatment of chronic venous ulcer: technical note

Chronic venous ulcers are a medical challenge with a socioeconomic impact. Tissue characterization was quantified by photographic imaging (p-CATIM) of a leg wound treated with Unna boot for 45 days. Three photographs, taken pre-treatment, post Unna boot and post healing were analyzed. Brightness on a 0-255 gray image was re-scaled with black as 0 and adjacent skin as 200. Gray Scale Median (GSM) and the percentages of pixels in each of 14 brightness intervals were calculated. Open ulcer GSM increased from 110 to 159 post Unna boot treatment, reaching 203 post healing. Predominant brightness intervals for the ulcer were 41-153 pre-treatment, 83% of pixels; 133-196 post Unna boot, 80%; and 175-255 post healing, 97%. The GSM of the subcutaneous wound around the ulcer increased from 117 to 137 post healing; the proportion of pixels in the 91-174 interval increased from 67% to 88% (p<0.001). CATIM quantified photographic changes during venous ulcer healing with comparison to the adjacent skin.

Photographic image tissue characterization of the ulcerated diabetic foot during treatment: technical note

Treatment of an ulcerated diabetic foot was documented photographically. We adapted the ultrasonographic tissue characterization (USTC or CATUS) technique to develop a photographic image tissue characterization (p-IMTC or CATIM) method. Five photographs, taken during medical treatment of an ulcerated diabetic foot following digital amputation, were quantified using imaging software designed to determine brightness intensity in grey scale images. The grey scale median (GSM) changed from 127 to 98; 86; 76; and 83 (out of 255) during follow-up. The area of lesion was estimated by number of pixels and reduced from 17.85 cm² to 12.44; 3.68; 2.11; and 0.15 cm². The percentage of total number of pixels showing granulation tissue increased from 11% to 34%; 56%; 62%; and 75%. p-IMTC quantified treatment progress. GSM quantified generalized changes in tissues, while the area of lesion and granulation tissue were documented quantitatively. Lesions, ulcers, wounds or other tissues can be analyzed using p-IMTC, allowing quantification, characterization and control of the progression of a condition or treatment.

Comparacoes preliminares entre a histologia virtual ultrassonografica in vivo e os achados histopatologicos da placa carotidea produto de endarterectomia

CONTEXTO: A doença aterosclerótica da carótida extracraniana é uma das principais causas evitáveis de acidente vascular cerebral isquêmico (AVCi), sendo este a segunda causa mais comum de morte nos países desenvolvidos. Nos grandes estudos sobre a cirurgia carotídea, a indicação estava embasada fundamentalmente no grau de estenose arterial. Analisar somente o grau de estenose, entretanto, não revela todas as características da placa, na medida em que a morfologia e a composição da placa complementam a avaliação da doença carotídea avançada e são fundamentais para a análise e o acompanhamento da maioria das placas carotídeas tratadas clinicamente. OBJETIVO: Correlacionar a caracterização dos componentes da placa de ateroma pela histologia virtual ultrassonográfica (HVUS) com a histologia. MÉTODOS: As imagens pré-operatórias obtidas por ultrassonografia transcutânea de 12 placas de ateroma de bifurcação carotídea foram submetidas a um programa de computador, o qual correlacionou os níveis de cinza com os prováveis componentes da placa da bifurcação carotídea (HVUS). Estes achados foram correlacionados com o exame anatomopatológico das placas coletadas pela cirurgia de endarterectomia. RESULTADOS: O coeficiente de correlação de Pearson para os conteúdos de lipídeos e músculo/tecido fibroso foram, respectivamente, R=0,83 para gordura e R=0,91 para músculo/tecido fibroso. Quanto ao cálcio e ao sangue, foram R=0,05 e R=0,19, respectivamente. CONCLUSÕES: O presente trabalho corrobora a literatura demonstrando que a histologia virtual computadorizada baseada em ultrassonografia transcutânea apresenta boa correlação com os achados da histologia quanto ao conteúdo da placa. Maiores estudos para a padronização da técnica e o aperfeiçoamento do programa de análise permitirão maior uso clínico deste método.