A semi-supervised network-based tissue-aware contrast enhancement method for CT images / 南方医科大学学报

OBJECTIVE@#To propose a tissue- aware contrast enhancement network (T- ACEnet) for CT image enhancement and validate its accuracy in CT image organ segmentation tasks.@*METHODS@#The original CT images were mapped to generate low dynamic grayscale images with lung and soft tissue window contrasts, and the supervised sub-network learned to recognize the optimal window width and level setting of the lung and abdominal soft tissues via the lung mask. The self-supervised sub-network then used the extreme value suppression loss function to preserve more organ edge structure information. The images generated by the T-ACEnet were fed into the segmentation network to segment multiple abdominal organs.@*RESULTS@#The images obtained by T-ACEnet were capable of providing more window setting information in a single image, which allowed the physicians to conduct preliminary screening of the lesions. Compared with the suboptimal methods, T-ACE images achieved improvements by 0.51, 0.26, 0.10, and 14.14 in SSIM, QABF, VIFF, and PSNR metrics, respectively, with a reduced MSE by an order of magnitude. When T-ACE images were used as input for segmentation networks, the organ segmentation accuracy could be effectively improved without changing the model as compared with the original CT images. All the 5 segmentation quantitative indices were improved, with the maximum improvement of 4.16%.@*CONCLUSION@#The T-ACEnet can perceptually improve the contrast of organ tissues and provide more comprehensive and continuous diagnostic information, and the T-ACE images generated using this method can significantly improve the performance of organ segmentation tasks.

Magnificación en la terapia endodóncica mediante el microscopio operatorio / Magnification in endodontic therapy through the operatory microscope

La microendodoncia involucra la visualización a través de un microscopio operatorio de todas las fases del tratamiento de conductos y procedimientos de cirugía apical y correctiva por parte del endodoncista. Existe sobrada evidencia acerca de las mejoras que puede aportar la magnificación al tratamiento; la literatura demuestra que la capacidad del operador mejora si su visión del campo gana claridad y precisión, ambos recursos pueden ser proporcionados por el microscopio operatorio, aunado a que posibilita diagnósticos más certeros junto con mejoras en el pronóstico, lo que permite evitar posibles complicaciones. La calidad de los tratamientos endodóncicos involucra infinidad de factores, cada uno relevante en sí mismo pero, en determinados casos, el microscopio puede significar la diferencia entre un tratamiento exitoso o un fracaso clínico. En la actualidad, se ha convertido en un tema de lo más relevante, por lo que el objetivo del presente trabajo es revisar la literatura con el fin de ayudar al entendimiento basado en evidencia científica de los criterios que determinan la relevancia del uso del microscopio en el ámbito endodóncico (AU)

Microendodontics involves the visualization through an operating microscope of all phases of root canal treatment and apical and corrective surgery procedures by the endodontist. There is plenty of evidence about the improvements that magnification can provide, the literature shows that the operator's ability improves if his vision of the field gains clarity and precision, both resources can be provided by the operating microscope, added to the fact that it enables more accurate diagnoses together with improvements in the prognosis allowing to avoid possible complications. The quality of endodontic treatments involves countless factors, each relevant in itself, but in certain cases the microscope can mean the difference between a successful treatment or a clinical failure. At present, it has become a very relevant topic, so the objective of this work is to review the literature in order to help understand the criteria that determine the relevance of the use of the microscope in the endodontic field based on scientific evidence (AU)

Application of Magnetization-prepared True Fast Imaging with Steady-state Precession Sequence in Brain Tumor Enhancement / 中国医学科学院学报

Objective To evaluate the application of two-dimensional magnetization-prepared true fast imaging with steady-state precession(2D-MP-TrueFISP)sequence in brain tumor enhancement.Methods In this study,60 cases of brain tumor patients who underwent enhanced magnetic resonance imaging of brain were scanned with 2D-MP-TrueFISP/two-dimensional spoiled gradient-recalled echo(2D-SPGR)before and after enhancement.The scores of lesions on the images of 2D-MP-TrueFISP/2D-SPGR were compared.At the same level of 2D-SPGE and 2D-MP-TrueFISP,the signal intensities(SIs)of lesions,white matter,and cerebrospinal fluid were measured before and after enhancement,and the contrast ratios(CRs)of lesions were calculated.The CRs before and after 2D-SPGR/2D-MP-TrueFISP enhancement and those between 2D-SPGR and 2D-MP-TrueFISP after enhancement were compared.Results The scores of lesions after 2D-MP-TrueFISP/2D-SPGR T1WI enhancement were 9.0(9.0,9.0)and 7.0(6.0,7.0),respectively,with significant difference(

Serum iron and vitamin B 12 deficiency could indicate celiac disease by flexible spectral imaging color enhancement

SUMMARY INTRODUCTION Celiac disease (CeD) is an autoimmune disease that can be delayed in diagnosis due to the presence of atypical and asymptomatic cases in adulthood. Herein we aimed to study the frequency of CeD and evaluate whether magnified endoscopy and magnified/FICE (flexible spectral imaging color enhancement) techniques contribute to the diagnosis in patients with serum iron and vitamin B12 deficiency. METHODS We evaluated 50 adult patients (10 males and 40 females) who had serum iron and vitamin B12 deficiency, prospectively. All the patients had undergone upper gastrointestinal system endoscopy by the same endoscopist. The second part of the duodenum was evaluated with white light, magnified, and magnified/FICE endoscopy. Biopsy specimens were evaluated by the same pathologist. The specimens diagnosed as CeD were classified according to the Modified Marsh-Oberhuber criteria. RESULTS 10 of 50 patients (20%) were diagnosed as CeD. The average age was 41±11 years (20-67 years). Thirty percent of CeD diagnosed patients had typical CeD symptoms. Six of 10 patients (60%) who were diagnosed as CeD had typical endoscopic images under white lighted endoscopy. All of these 10 patients (100%) showed villous irregularity, partial villous atrophy, or total villous atrophy consistent with CeD with magnified and magnified/FICE endoscopy. CONCLUSION The practical use of magnified/FICE endoscopy allows us to differentiate mucosal abnormalities of the duodenum and minimize false-negative results that indicate normal mucosal findings with conventional endoscopy.

RESUMO INTRODUÇÃO A doença celíaca (DC) é uma doença autoimune que pode ter seu diagnóstico atrasado devido à presença de casos atípicos e assintomáticos na idade adulta. Neste trabalho, objetivamos estudar a frequência de DC e avaliar se as técnicas de endoscopia magnificada e magnificada/Fice (flexible spectral imaging color enhancement) contribuem para o diagnóstico em pacientes com deficiência sérica de ferro e vitamina B12. MÉTODO Foram avaliados prospectivamente 50 pacientes adultos (10 homens e 40 mulheres) com deficiência sérica de ferro e vitamina B12. Todos os pacientes foram submetidos a endoscopia digestiva alta pelo mesmo endoscopista. A segunda parte do duodeno foi avaliada com endoscopia com luz branca, magnificada e magnificada/Fice. As amostras de biópsia foram avaliadas pelo mesmo patologista. Os espécimes diagnosticados como DC foram classificados de acordo com os critérios de Marsh-Oberhuber modificado. RESULTADOS Dez dos 50 pacientes (% 20) foram diagnosticados como DC. A idade média foi de 41±11 anos (20-67 anos). Trinta por cento dos pacientes diagnosticados com DC apresentaram sintomas típicos de DC. Seis dos dez pacientes (60%) diagnosticados com DC tinham imagens endoscópicas típicas sob endoscopia de luz branca. Todos esses dez pacientes (% 100) apresentaram irregularidade das vilosidades, atrofia das vilosidades parciais ou atrofia das vilosidades totais consistentes com a DC com endoscopia magnificada e magnificada/Fice. CONCLUSÃO O uso prático da endoscopia magnificada/Fice permite diferenciar anormalidades mucosas do duodeno e minimizar os resultados falso-negativos que apresentam achados mucosais normais com a endoscopia convencional.

The SAR Problem and Trouble Shooting Strategy / 中国医疗器械杂志

The modifications of slices, flip angle, SAR mode and TR time are required when the SAR exceeds the limits. The scan time and image quality are affected by those. This study analyzes the SAR from the basic side. With the principle diagram of SIEMENS 1.5 T AVANTO and 3.0 T VERIO MRIS, the trouble shooting procedure of SAR problem is reached both in application and problem sides.

Myocardial Coverage and Radiation Dose in Dynamic Myocardial Perfusion Imaging Using Third-Generation Dual-Source CT

Method for Automated Selection of the Trabecular Area in Digital Periapical Radiographic Images Using Morphological Operations / 대한의료정보학회지

OBJECTIVES: The aim of this study is to propose a method that automatically select the trabecular bone area in digital periapical radiographic images using a sequence of morphological operations. METHODS: The study involved 50 digital periapical radiographic images of women aged from 36 to 58 years old. The proposed method consists of three stages: teeth detection, trabecular identification, and validation. A series of morphological operations-top-hat and bottom-hat filtering, automatic thresholding, closing, labeling, global thresholding, and image subtraction-are performed to automatically obtain the trabecular bone area in images. For validation, the results of the proposed method were compared with those of two dentists pixel by pixel. Three parameters were used in the validation: trabecular area, percentage of agreed area, and percentage of disagreed area. RESULTS: The proposed method obtains the trabecular bone area in a polygon. The obtained trabecular bone area is usually larger than that of previous studies, but is usually smaller than the dentists'. On average over all images, the trabecular area produced by the proposed method is 5.83% smaller than that identified by dentists. Furthermore, the average percentage of agreed area and the average percentage of disagreed area of the proposed method against the dentists' results were 75.22% and 8.75%, respectively. CONCLUSIONS: The shape of the trabecular bone area produced by the proposed method is similar and closer to that identified by dentists. The method, which consists of only simple morphological operations on digital periapical radiographic images, can be considered for selecting the trabecular bone area automatically.

Image Quality and Radiation Dose in CT Venography Using Model-Based Iterative Reconstruction at 80 kVp versus Adaptive Statistical Iterative Reconstruction-V at 70 kVp

OBJECTIVE: To compare the objective and subjective image quality indicators and radiation doses of computed tomography (CT) venography performed using model-based iterative reconstruction (MBIR) at 80 kVp and adaptive statistical iterative reconstruction (ASIR)-V at 70 kVp. MATERIALS AND METHODS: Eighty-three patients who had undergone CT venography of the lower extremities with MBIR at 80 kVp (Group A; 21 men and 20 women; mean age, 55.5 years) or ASIR-V at 70 kVp (Group B; 18 men and 24 women; mean age, 57.3 years) were enrolled. Two radiologists retrospectively evaluated the objective (vascular enhancement, image noise, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) and subjective (quantum mottle, delineation of contour, venous enhancement) image quality indicators at the inferior vena cava and femoral and popliteal veins. Clinical information, radiation dose, reconstruction time, and objective and subjective image quality indicators were compared between groups A and B. RESULTS: Vascular enhancement, SNR, and CNR were significantly greater in Group B than in Group A (p ≤ 0.015). Image noise was significantly lower in Group B (p ≤ 0.021), and all subjective image quality indicators, except for delineation of vein contours, were significantly better in Group B (p ≤ 0.021). Mean reconstruction time was significantly shorter in Group B than in Group A (1 min 43 s vs. 131 min 1 s; p < 0.001). Clinical information and radiation dose were not significantly different between the two groups. CONCLUSION: CT venography using ASIR-V at 70 kVp was better than MBIR at 80 kVp in terms of image quality and reconstruction time at similar radiation doses.

Research on Improved Algorithm of DR Image Enhancement Based on Gauss-Laplacian Pyramid / 中国医疗器械杂志

OBJECTIVE@#In order to obtain more decision information from Digital Radiography(DR) images, an improved image enhancement algorithm is proposed based on the algorithm of Gauss-Laplacian pyramid.@*METHODS@#The original algorithm is improved on the basis of the human visual characteristics and better enhancements, the low frequency components of the image is histogram equalized to make the image gray scale more balanced, and the high frequency component is enhanced by a hierarchical exponential enhancement to make the details of the image clearer.@*RESULTS@#The improved algorithm improves the contrast of DR images in chest, pelvic and spine, and makes the image more layered and obtains good image enhancement effect.@*CONCLUSIONS@#The results show that the improved algorithm is superior to the traditional algorithm in terms of image enhancement.

Super-resolution construction of intravascular ultrasound images using generative adversarial networks / 南方医科大学学报

The low-resolution ultrasound images have poor visual effects. Herein we propose a method for generating clearer intravascular ultrasound images based on super-resolution reconstruction combined with generative adversarial networks. We used the generative adversarial networks to generate the images by a generator and to estimate the authenticity of the images by a discriminator. Specifically, the low-resolution image was passed through the sub-pixel convolution layer -feature channels to generate -feature maps in the same size, followed by realignment of the corresponding pixels in each feature map into × sub-blocks, which corresponded to the sub-block in a high-resolution image; after amplification, an image with a -time resolution was generated. The generative adversarial networks can obtain a clearer image through continuous optimization. We compared the method (SRGAN) with other methods including Bicubic, super-resolution convolutional network (SRCNN) and efficient sub-pixel convolutional network (ESPCN), and the proposed method resulted in obvious improvements in the peak signal-to-noise ratio (PSNR) by 2.369 dB and in structural similarity index by 1.79% to enhance the diagnostic visual effects of intravascular ultrasound images.

Multicentre study on dynamic contrast computed tomography findings of focal liver lesions with clinical and histological correlation

Background: Current advancements in dynamic contrast imaging of the liver have enabled increased sensitivity in the diagnosis of liver lesions. Evaluation and characterisation of the enhancement pattern of liver lesions in respect to the liver parenchyma aids in making a specific diagnosis.Objectives: The aim of this study was to determine the liver findings on dynamic contrast computed tomography (CT) scanning and correlate them with clinicopathologic findings. Methods: This prospective cross-sectional study included 61 patients and took place between August 2017 and February 2018. Dynamic contrast CT was performed and the images were evaluated by two experienced radiologists. Correlation of the CT findings with histology results from an ultrasound-guided biopsy was done. Data analysis was performed using SPSS version 20.0. Results: Hepatocellular carcinoma (HCC) was the most common malignant lesion seen and showed three patterns of enhancement: homogenous, abnormal internal vessels and heterogeneous enhancement. Abnormal internal vessel pattern was most specific (90.6%) and showed a high positive predictive value (PPV) of 78.6%. Rapid washout showed a specificity of 87.5% and a PPV of 72.2% in the diagnosis of HCC. Dynamic contrast CT scan had a sensitivity of 93%, specificity of 50%, PPV of 91% and diagnostic accuracy of 95.5% in differentiation of benign and malignant liver lesions. Considering only Liver Imaging Reporting and Data System (LI-RADS) category 5 as conclusive for HCC diagnosis, our study did not miss a significant number of HCCs. Liver Imaging Reporting and Data System category 5 showed specificity of 81.3% and PPV of 75%. Conclusion: Enhancement patterns on a dynamic contrast CT scan of the liver are useful in the interpretation of CT images for specific diagnoses

7. 0T ultrahigh-field MRI directly visualized the pedunculopontine nucleus in Parkinson's disease patients

OBJECTIVES: The pedunculopontine nucleus (PPN) is considered a promising new target for neurostimulation in Parkinson's disease (PD) patients with postural instability and gait disturbance that is refractory to other treatment modalities. However, the PPN is typically difficult to visualize with magnetic resonance imaging (MRI) at clinical field strengths, which greatly limits the PPN as a viable surgical target for deep brain stimulation (DBS). Thus, the aim of this study is to directly visualize the PPN based on 7.0T ultrahigh-field MRI. METHODS: Five PD patients were enrolled and scanned using the MP2RAGE sequence on a 7.0T ultrahigh-field MRI scanner. Then, the MP2RAGE sequences were imported into a commercially available navigation system. The coordinates of the directly localized PPN poles were recorded in the navigation system relative to the anterior commissure-posterior commissure plane. RESULTS: Our results indicated that the PPN presented intermediate signal intensity in the 7.0T ultrahigh-field MR images in comparison with the surrounding structure, such as the hypo-intensity of the periaqueductal gray and the hyperintensity of the neighboring white matter tracts, in PD patients. The mean coordinates for the rostral and caudal poles of PPN were 6.50 mm and 7.20 mm lateral, 1.58 mm and 2.21 mm posterior, and 8.89 mm and 13.83 mm relative to the posterior commissure. CONCLUSION: Our findings provide, for the first time, direct visualization of the PPN using the MP2RAGE sequence on a 7.0T ultrahigh-field MRI, which may improve the accuracy of stereotactic targeting of the PPN and improve the outcomes in patients undergoing DBS.

Recursos actuales en el diagnóstico de caries / Current resources in caries diagnosis

Uno de los grandes problemas en la Odontología y en particular en aquellos asociados con el manejo de la caries dental es la detección y el diagnóstico preciso o acertado de las lesiones de caries, principalmente, de aquellas lesiones más incipientes. Actualmente, así como se ha ido presentando una mayor comprensión y entendimiento del desarrollo de las lesiones de la caries dental, también se han generado nuevas posibilidades de efectuar un mejor manejo de estas lesiones en forma individual y en general, a la disminución del riesgo de caries de cada paciente en forma más particular. Esto ha permitido la creación de lo que se puede considerar como un nuevo paradigma basado en los recursos actuales, no sólo en el diagnóstico de las lesiones de caries sino en especial, al manejo de la caries dental como enfermedad (AU)

One of the great problems in Dentistry and especially in those associated with the management of dental caries is the detection and the precise or accurate diagnosis of the caries lesions, particularly of the most incipient lesions. Actually, to our date, it has been shown a better comprehension and understanding on the development of the dental caries lesions that has generated also, the possibilities to perform a better management of these lesions individually, and in general, to decrease the caries risk in each patient in a particular form. All this has created what can be considered as: a new paradigm based in the current resources not only on the diagnosis of the caries lesions, but specially, on the management of dental caries as a disease (AU)

Localización de la desembocadura del foramen apical en caninos superiores / Location of upper canine apical foramen opening

Objetivo: Evaluar radiográfica y macroscópicamente la desembocadura del foramen apical en caninos superiores. Materiales y métodos: Se seleccionaron 300 caninos superiores recientemente extraídos, siguiendo las normas del Comité de Ética de la Universidad Maimónides. Los dientes fueron conservados en una solución fisiológica y glicerina (ana/ana) hasta el momento de su utilización. Se tomaron radiografías preoperatorias en sentido ortorradial y próximo-proximal. Las aperturas fueron realizadas con piedra redonda de diamante #3, y la preparación de los tercios coronario y medio, con fresas de Gates Glidden #1, 2 y 3. Luego se introdujo una lima K #15 hasta que se constató visualmente su salida por el foramen apical mediante una lupa X6 (Ballon). Después se procedió a la toma radiográfica en sentido vestíbulo-palatino y próximo-proximal. Los criterios de valoración radiográfica fueron: incidencia radiográfica ortorradial: mesial (M), distal (D) y coincidencia (C); incidencia radiográfica próximo-proximal: vestibular (V), palatino (P) y coincidencia (C). Los criterios de valoración macroscópica fueron: vestibulodistal (DV), distopalatino (DP), mesiovestibular (MV), mesiopalatino (MP), mesial (M), palatino (P), vestibular (V), distal (D) y coincidencia (C). La desembocadura de los forámenes fue evaluada macroscópicamente con una lupa estereoscópica (ZTX-F2, Lancet) a 30X. Los datos de las evaluaciones fueron registrados en una planilla de Excel (Microsoft). Para efectuar el análisis estadístico, se empleó la prueba de frecuencia relativa en porcentaje, con intervalo de confianza de 95%. Resultados: Se encontraron diferencias estadísticas (P<0,0001) entre la incidencia radiográfica bucolingual y la vista macroscópica. No se encontraron diferencias estadísticas (P>0,5) entre la incidencia radiográfica mesiodistal y la vista macroscópica. Se encontraron diferencias estadísticas al comparar todas las vistas macroscópicas con todas las coincidencias radiográficas (P<0,0001). Conclusiones: En las condiciones en que se realizó este estudio, la terminación más frecuente del foramen apical en una incidencia radiográfica ortorradial fue hacia distal (43%), y en una vista próximo-proximal, hacia vestibular (47%). Macroscópicamente, la desembocadura más frecuente del foramen apical fue hacia distovestivular (27,7%), seguida de una coincidencia con el ápice anatómico (25,3%) (AU)

Aim: To evaluate the localization of the opening of the apical foramen of maxillary canines. Materials and methods: 300 recently extracted maxillary canines were selected and stored in a/a saline solution/glicerine. The teeth were radiographed in two directions: mesiodistal and buccolingual directions. The access cavity was prepared with a diamond round bur 3, and Gates Glidden burs 1, 2 and 3 were used to shape the coronal and middle third of the root canal. A K-file 15 was introduced in the root canal until its tip was seen at the opening of the apical foramen. Then, buccolingual and mesiodistal radiographs were taken. The evaluation followed these radiographic criteria: Buccolingual direction: mesial (M), distal (D), and coincidence (C). Mesiodistal direction: buccal (V), lingual (P), and coincidence (C). The macroscopic criteria: distobuccal (DV), distolingual (DP), mesiobuccal (MV), mesiolingual (MP), mesial (M), lingual (P), buccal (V), distal (D) and coincidence (C). The openings of the apical foramen were macroscopically evaluated using magnification (30X). Data were statistically analyzed using the relative frequency tests and 95% confidence intervals. Results: Statistical differences were found (P<0.0001) ortobetween buccolingual incidence and macroscopic view. No statistical differences were found (P>0.05) between mesiodistal and macroscopic view. Statistical differences were found comparing all macroscopic views with all radiographic coincidences (P<0.0001). Conclusions: The most frequent localization of the opening of the apical foramen was distal in a buccolingual radiographic direction (43%), and buccal in a mesiodistal view (47%). Macroscopically, the most frequent localization of the opening of the apical foramen was distobuccal (27.7%), followed by coincidence with the anatomic apex (25.3%) (AU)

Rendimiento de la mamografía espectral de energía dual con contraste en la detección de cáncer de mama: experiencia en un centro de referencia / Contrast-enhanced spectral mammography: experience in 465 examinations

Background: Contrast-enhanced spectral mammography or "contrast mammography" has a better cost effectiveness than breast magnetic resonance for confirmation of suspicious lesions detected on breast screening programs. Aim: To report the experience of a single center in Santiago. Material and Methods: All patients referred for contrast mammography between July 2015 and October 2017 were studied. We recorded the patient risk factors for breast cancer. In 85 patients with suspicious lesions, biopsy results were available. Results: We analyzed 465 contrast mammographies. The most common clinical indications were suspicion of cancer and previous inconclusive studies. Mass type lesions were detected in 33% of the studies. Non-mass-type lesions were observed in 10% of cases and findings compatible with papillomatosis in 2%. Fifty five percent of the studies had no visible lesions. In the 85 patients with a pathological study of the biopsy, the sensitivity of the contrast mammography was 100%, with a diagnostic accuracy of 85%, positive and negative predictive values of 82 and 100% respectively. Conclusions: Contrast mammography can be of great use for the assessment of patients with an altered conventional mammography, before indicating a magnetic resonance imaging or a percutaneous biopsy.

Dynamic contrast-enhanced magnetic resonance imaging; a useful tool for characterization and assessment of ovarian masses

Objectives: To evaluate the diagnostic performance of dynamic contrast enhanced magnetic resonance imaging [DCE-MRI] for the characterization of complex ovarian tumors, by using histologic findings as the reference standard

Patients and methods: 25 patients [age range from 24 to 60] with complex ovarian masses underwent DCE-MRI before surgical excision. The study included 8 benign, 3 borderline and 14 malignant masses. The following kinetic parameters were analyzed: enhancement amplitude [EA] in the form of MRE%, time to peak in the form of T max and maximal slope [MS] and correlated with histopathological results

Results: DCE-MRI achieved higher overall accuracy [85.7%] and specificity [86.5%] than conventional MRI. MRE% was higher for malignant than for benign [p0.001] and borderline masses [p0.002]. T max was of shorter duration in malignant than in benign [p, < 0.001] and borderline [p, 0.018] masses. Type III curve was specific for invasive malignant tumors

Conclusion: DCE-MRI can be a useful tool in characterization of complex ovarian masses and in differentiating between borderline and invasive malignant neoplasms

Image-Enhanced Endoscopy in Lower Gastrointestinal Diseases: Present and Future

From dye-assisted conventional chromoendoscopy to novel virtual chromoendoscopy, image-enhanced endoscopy (IEE) is continuously evolving to meet clinical needs and improve the quality of colonoscopy. Dye-assisted chromoendoscopy using indigo carmine or crystal violet, although slightly old-fashioned, is still useful to emphasize the pit patterns of the colonic mucosa and predict the histological structures of relevant lesions. Equipment-based virtual chromoendoscopy has the advantage of being relatively easy to use. There are several types of virtual chromoendoscopy that vary depending on the manufacturer and operating principle. IEE plays distinctive roles with respect to histologic characterization of colorectal polyps and prediction of the invasion depth of colorectal cancers. In addition, the newest models of IEE have the potential to increase adenoma and polyp detection rates in screening colonoscopy.

A Prospective Blinded Study of Endoscopic Ultrasound Elastography in Liver Disease: Towards a Virtual Biopsy

BACKGROUND/AIMS: Liver biopsy has traditionally been used for determining the degree of fibrosis, however there are several limitations. Endoscopic ultrasound (EUS) real-time elastography (RTE) is a novel technology that uses image enhancement to display differences in tissue compressibility. We sought to assess whether liver fibrosis index (LFI) can distinguish normal, fatty, and cirrhotic liver tissue. METHODS: A total of 50 patients undergoing EUS were prospectively enrolled. RTE of the liver was performed to synthesize the LFI in each patient. Univariate and multivariable analyses were performed. Chi-square and t-tests were performed for categorical and continuous variables, respectively. A p-value of <0.05 was considered significant. RESULTS: Abdominal imaging prior to endoscopic evaluation suggested normal tissue, fatty liver, and cirrhosis in 26, 16, and 8 patients, respectively. Patients with cirrhosis had significantly increased mean LFI compared to the fatty liver (3.2 vs. 1.7, p<0.001) and normal (3.2 vs. 0.8, p<0.001) groups. The fatty liver group showed significantly increased LFI compared to the normal group (3.8 vs. 1.4, p<0.001). Multivariable regression analysis suggested that LFI was an independent predictor of group features (p<0.001). CONCLUSIONS: LFI computed from RTE images significantly correlates with abdominal imaging and can distinguish normal, fatty, and cirrhotic-appearing livers; therefore, LFI may play an important role in patients with chronic liver disease.

Repeatability of the "flash-replenishment" method in contrast-enhanced ultrasound for the quantitative assessment of hepatic microvascular perfusion

This study aimed to evaluate the feasibility and repeatability of the flash-replenishment method in contrast-enhanced ultrasound (CEUS) perfusion imaging and assess quantitatively microvascular perfusion in the liver. Twenty healthy New Zealand rabbits were submitted to CEUS perfusion imaging with continuous intravenous infusion. Using flash-replenishment kinetics, the dynamic process of depletion and refilling of microbubble contrast agent was recorded. The hepatic microvascular perfusion parameters were calculated, including region of interest, peak intensity (PI), area under the curve (AUC), and hepatic artery to vein transit time (HA-HVTT). A consistency test was performed for multiple measurements by the same operator and blind measurements by two different operators. The hepatic perfusion imaging of 3×108 bubbles/min had minimal error and the best imaging effect and repeatability. The variability of the perfusion parameter measured at 3 cm depth under the liver capsule was at a minimum with coefficient of variation of 3.9%. The interclass correlation coefficient (ICC) of measurements taken by the same operator was 0.985, (95% confidence interval, CI=0.927-0.998). Measurements taken by two operators had good consistency and reliability, with the ICC of 0.948 (95%CI=0.853-0.982). The PI and AUC of liver parenchyma after reperfusion were lower than before blocking; and HA-HVTT was significantly longer than before blocking (P<0.05). The flash-replenishment method in CEUS perfusion imaging showed good stability and repeatability, which provide a valuable experimental basis for the quantitative assessment of hepatic microvascular perfusion in clinical practice.

audit to evaluate the image quality of magnetic resonance of knee at radiology department of a tertiary care hospital

Objective: To evaluate the quality of MRI scans of knee, performed at Radiology Department of Jinnah Hospital in the light of recommendations of ACR

Study Design: A clinical audit

Place and Duration of Study: Department of Radiology, Jinnah Hospital, Lahore, from August 2015 to February 2016

Methodology: Scans of 20 patients who underwent MRI of knee in August 2015 were studied retrospectively to assess the quality of images obtained in the first audit. Based on the findings of this audit, recommendations were made and re audit was done 6 months later in February 2016 to look for improvement in local practice

Results: In the first audit, images were acquired in all the three necessary planes and the sagittal and coronal images had appropriate slice thickness, interslice gap as well as adequate anatomical coverage in all the patients. However, FOV [field of view] was appropriately set in 66% of cases in axial plane, 5% in sagittal plane, and 0% in coronal plane. Also, the anatomical coverage was not upto the mark in axial plane with 13 studies [66%] having adequate superior coverage, and 16 cases [80%] having recommended inferior anatomical coverage. The re audit performed 6 months later showed improvement with 100% compliance to standards

Conclusion: The first audit showed many shortcomings in acquiring of MRI data in patients undergoing knee MRI with FOV requiring a decrease in all planes and anatomical coverage increase in axial plane. These recommendations were made in departmental meetings and re-audit was done after 6 months. This second audit showed 100 % compliance