Automatic segmentation of coronary lumen and external elastic membrane in intravascular ultrasound images using 8-layer U-Net

BACKGROUND

Intravascular ultrasound (IVUS) is the golden standard in accessing the coronary lesions, stenosis, and atherosclerosis plaques. In this paper, a fully automatic approach by an 8-layer U-Net is developed to segment the coronary artery lumen and the area bounded by external elastic membrane (EEM), i.e., cross-sectional area (EEM-CSA). The database comprises single-vendor and single-frequency IVUS data. Particularly, the proposed data augmentation of MeshGrid combined with flip and rotation operations is implemented, improving the model performance without pre- or post-processing of the raw IVUS images.

RESULTS

The mean intersection of union (MIoU) of 0.937 and 0.804 for the lumen and EEM-CSA, respectively, were achieved, which exceeded the manual labeling accuracy of the clinician.

CONCLUSION

The accuracy shown by the proposed method is sufficient for subsequent reconstruction of 3D-IVUS images, which is essential for doctors' diagnosis in the tissue characterization of coronary artery walls and plaque compositions, qualitatively and quantitatively.

Segmentation of finger tendon and synovial sheath in ultrasound image using deep convolutional neural network

BACKGROUND

Trigger finger is a common hand disease, which is caused by a mismatch in diameter between the tendon and the pulley. Ultrasound images are typically used to diagnose this disease, which are also used to guide surgical treatment. However, background noise and unclear tissue boundaries in the images increase the difficulty of the process. To overcome these problems, a computer-aided tool for the identification of finger tissue is needed.

RESULTS

Two datasets were used for evaluation: one comprised different cases of individual images and another consisting of eight groups of continuous images. Regarding result similarity and contour smoothness, our proposed deeply supervised dilated fully convolutional DenseNet (D2FC-DN) is better than ATASM (the state-of-art segmentation method) and representative CNN methods. As a practical application, our proposed method can be used to build a tendon and synovial sheath model that can be used in a training system for ultrasound-guided trigger finger surgery.

CONCLUSION

We proposed a D2FC-DN for finger tendon and synovial sheath segmentation in ultrasound images. The segmentation results were remarkably accurate for two datasets. It can be applied to assist the diagnosis of trigger finger by highlighting the tissues and generate models for surgical training systems in the future.

METHODS

We propose a novel finger tendon segmentation method for use with ultrasound images that can also be used for synovial sheath segmentation that yields a more complete description for analysis. In this study, a hybrid of effective convolutional neural network techniques are applied, resulting in a deeply supervised dilated fully convolutional DenseNet (D2FC-DN), which displayed excellent segmentation performance on the tendon and synovial sheath.

The membranous layer of superficial fascia: evidence for its widespread distribution in the body

A discrete membranous layer, "stratum membranosum", in human subcutaneous tissue is classically described as confined to the lower anterior abdominal wall and perineum and referred to as Scarpa's and Colles' fasciae, respectively. Evidence for its existence elsewhere in the body is scanty and therefore the present study was undertaken. Dissection of six embalmed adult cadavers, along with ultrasound imaging on four living subjects, were carried out to determine the existence, topography, and thickness of the membranous layer of superficial fascia in different regions of the body. In all six cadavers, a continuous layer of fibrous membrane in the superficial fascia was found consistently in all the dissected regions of the body and was also confirmed by ultrasonography. The arrangement and thickness of this membranous layer varied according to body region, body surface, and gender. It was thicker in the lower than in the upper extremity, on the posterior than anterior aspect of the body, and in females than in males. The mean thickness of the membranous layer ranged from 39 to 189 mum, being thickest in the leg and thinnest over the dorsum of the hand. The membranous layer was observed to have two or even three components in regions such as the breast, back, thigh, and arm and was seen to split, forming special compartments around subcutaneous major veins of upper and lower extremities, with fibrous septa extending to attach to the vessel wall. Functionally, the membranous superficial fascia may play a role in the integrity of the skin and support for subcutaneous structures particularly veins, by ensuring their patency. Understanding the topographic anatomy of this fascial layer may help explain body-contour deformities and provide the anatomic basis for surgical correction.

Supracardiac total anomalous pulmonary venous connection with a supramitral ring: a rare, surgically correctable anomaly

Total anomalous pulmonary venous connection is rarely associated with a supramitral ring. This condition should be suspected in any infant having total anomalous pulmonary venous connection with obstruction to the pulmonary venous return. Preoperative echocardiography is usually successful in detecting the lesion. The Shumaker and King repair for total anomalous pulmonary venous connection is most appropriate for such composite lesions as it enables the surgeon to identify the membrane and excise it easily and completely. We report one such case.

Iliolumbar membrane, a newly recognised structure in the back

Despite intensive research in the anatomical sciences for the last two centuries, some structures of the human body still remain controversial or incompletely described. We describe a new membranous fascial anatomical entity, which we refer to as the iliolumbar membrane (ILM). During the 2004-2005 academic semesters at the American University of the Caribbean School of Medicine we dissected 40 human cadavers fixed in formalin-alcohol-phenol solution. Iliolumbar membrane is a thick connective tissue structure, deep to the skin, originating from the fibres of the thoracolumbar fascia at the lateral border of the erector spinae. It runs inferior to the superior border of the iliac crest, lateral to the posterior superior iliac spine, overlying the iliac crest at the level of the 4th lumbar vertebra. Iliolumbar membrane terminates within subcutaneous fat, where it divides into multiple layers. All cadavers showed considerable variation in the blending of the membrane's multiple layers with the subcutaneous fat. However, all specimens consistently showed a uniform appearance of ILM at the point of origin. Iliolumbar membrane could be demonstrated objectively by ultrasound examination with a frequency of 7.5 MHz and also with a Stryker endoscope. A hypothesis is put forth, conjecturing that this new structure may have relevance in creating a natural barrier between the musculature of the back and the muscles of the gluteal region, similar to Scarpa's fascia of the anterior abdominal wall.

Sonographic evaluation of lower extremity interosseous membrane injuries: retrospective review in 3 patients

OBJECTIVE

To describe the sonographic findings of lower extremity interosseous membrane disruption with computed tomographic and surgical correlation.

METHODS

Three patients with sonographic evaluation of the lower extremity interosseous membrane were identified through the clinical experience of 1 author over a 5-year period. Sonographic images of the symptomatic and unaffected lower extremities were retrospectively characterized and correlated with computed tomographic and surgical findings by 2 fellowship-trained musculoskeletal radiologists.

RESULTS

The normal interosseous membrane was identified in the asymptomatic lower extremities in all 3 patients, which appeared as a thin, hyperechoic (nearly equal to bone cortex) line, continuous from the tibia to the fibula. The abnormal interosseous membrane in all 3 cases appeared abnormally hypoechoic, poorly defined, and discontinuous at the tibia. A proximal fibular fracture was shown on sonography in 1 of 3 symptomatic lower extremities with radiographic evidence of a fracture. The sonographic findings correlated with the computed tomographic images. Distal tibiofibular syndesmosis injuries were confirmed and treated at surgery in 2 patients.

CONCLUSIONS

Sonography can show both normal and injured interosseous membranes of the lower extremity, as well as associated proximal fibular fractures.

The efficacy of magnetic resonance imaging and ultrasound in detecting disruptions of the forearm interosseous membrane: a cadaver study

The purpose of this study was to examine the efficacy of magnetic resonance imaging (MRI) and ultrasound (US) in determining complete disruptions of the central portion of the forearm interosseous membrane. The midportion of the forearm interosseous ligament was longitudinally incised in 19 fresh-frozen cadaver arms. The specimens were imaged with MRI and US. The MRIs were examined by a hand surgeon, a musculoskeletal radiologist, and a general radiologist, all blinded to the state of the interosseous membrane. The musculoskeletal radiologist and general radiologists read the real-time US images in a consensus fashion. Magnetic resonance imaging showed a 96% accuracy rate, a 100% positive predictive value, a 93% negative predictive value, 93% sensitivity, and 100% specificity. Kappa analysis showed substantial interobserver agreement for MRI. Ultrasound showed a 94% accuracy rate, a 94% positive predictive value, a 100% negative predictive value, 100% sensitivity, and 89% specificity. There was no statistical significance between the accuracy of MRI and US. We conclude that MRI and US imaging should both be considered when forearm interosseous membrane integrity is in question.

Nonobstructive membranes of the left atrial appendage cavity: report of three cases

A membranous structure causing functional stenosis at the mouth of the left atrial appendage (LAA) has been reported. In this study we describe the presence of nonobstructive membranes traversing the cavity of the LAA found incidentally on transesophageal echocardiography (TEE).

Rotational instability and integrity of the interosseous membrane in cadaveric ulnar shaft fractures

The stability of isolated ulnar shaft fractures required further investigation because no data were available for fractures in the middle third or on the effect on rotational stability. Ten intact cadaveric arms were used to study the pathomechanics of fractures of the middle ulna. In all of them a transverse osteotomy was performed (A), then in five of them, an additional osteotomy was done in order to create a third fragment (B). The interosseous membrane was subsequently divided for 2 cm on either side of the osteotomy (A-->C, C-->D). On radiographs the displacement was recorded in pronation and supination, and the rotational displacement was calculated. Rotational instability occurred in all fractures studied, even in the so-called stable ones. Also, dissection of the interosseous membrane was not followed by a displacement of more than 50%, and shortening of the ulna should also be considered in fractures with less than 50% displacement as a sign of instability.

The interosseous membrane in radio-ulnar dissociation

In severe forearm injuries, the diagnosis of disruption of the interosseous membrane is frequently delayed and sometimes missed, giving difficulties in the salvage of forearm stability. We studied the structure and function of the interosseous membrane in 11 cadaver preparations, using mechanical and histological analysis. Seven of the specimens tested in uniaxial tension sustained a mid-substance tear of the central band of the membrane at a mean peak load of 1038 +/- 308 N. The axial stiffness was 190 +/- 44 N/mm with elongation to failure of 10.34 +/- 2.46 mm. These results provide criteria for the evaluation of reconstructive methods. A preliminary clinical investigation of the use of ultrasound suggests that this may be of value in the screening of patients with complex fractures of the forearm, and for investigating the natural history of tears of the interosseous membrane.

Idiopathic peripheral vitreous membranes

An unusual case of bilateral prepapillary glial sheets and peripheral vitreal membranes is described. Such membranes are seldom reported in the literature. A retinal specialist concurred that the avascular membranes, present in the inferior retinae of both eyes, were congenital because the membranes were bilateral and symmetrical and because the patient had no other sign of retinal or systemic conditions associated with membrane formation. There were fenestrations in the membranes, which gave the initial impression of retinal tears and associated detachment However, there were no retinal breaks beneath the membranes nor was there any evidence of retinitis, myopia, or any other mechanism which could be considered causative for a vitreal membrane. Diseases associated with membrane formation and the confusion of the membranes with retinal detachment are discussed.

The use of sonography for evaluation of the integrity and healing process of the tibiofibular interosseous membrane in ankle fractures

This study evaluates the value of sonography in the diagnosis of the rupture and healing process of the interosseous membrane in Weber type B and C ankle fractures. In 90 such fractures a rupture of the interosseous membrane was intraoperatively observed in 35 cases (38.8%). All Weber type C fractures showed a rupture of the interosseous membrane, whereas only 23% of the Weber type B fractures were associated with a rupture of the interosseous membrane (p < 0.001). In the vast majority of the cases (77%), particularly in all Weber type B fractures (p < 0.01), the rupture of the interosseous membrane extended above the proximal fracture line of the fibula. By means of sonography, in the acute posttrauma period a rupture of the interosseous membrane was found in 37.4% of the cases. Thus, in our series the results of sonography and the operative findings coincided in 88.6% of the cases concerning location, type, and extent. Sonography was performed by three unbiased observers, and the results were compared with the intraoperative findings. Thus, the sensitivity of the sonography in the diagnosis of the rupture of the interosseous membrane was 88.8%, the diagnostic value of the method 92.2%, and specificity 94.5%. The sonographic findings of the healing process of the interosseous membrane were in absolute (100%) agreement with the intraoperative observations at the time of removal of the osteosynthesis material. Complete healing occurred within 3-5 months after trauma in 70% of the cases of ruptured interosseous membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

A histologic and biochemical comparison of the interface tissues in cementless and cemented hip prostheses

Thirty-four membranes from 20 cementless and 14 cemented prostheses from 33 patients excised during revision arthroplasty were analyzed for foreign-body reactive processes. As a control, identical analyses were performed using adjacent pseudocapsular tissue taken from 12 patients during revision arthroplasty. Histologically, cementless membranes tended to contain more metal debris, and cemented membranes contained more foreign-body giant cells. Collagenase, gelatinase, prostaglandin E2, and interleukin-1 were measured in conditioned media taken from organ cultures of each interface membrane. Both cementless and cemented membranes released significant levels of gelatinase and collagenase, prostaglandin E2, and interleukin-1 into the conditioned media when compared with control tissues. However, the tissue concentrations were not significantly different between cementless and cemented membranes. Although histologic differences between cementless and cemented interface membranes exist, both share a similar capacity to release bioactive products that can induce bone resorption and cause aseptic loosening of the hip prostheses.

[Ultrasonic evaluation of biomechanical properties of the interosseus membranes of the forearm. I. Selection of a quality index]

In the article is presented the echographic semiotics of the forearm interosseous membrane, based on the results of 10 forearm examinations. Qualitative echographic parameters, describing the forearm interosseous membrane geometry in different biomechanical situations, have been analysed. It has been determined that the ultrasound echography permits to visualize for certain the forearm interosseous membrane. As the criteria of the membrane geometry can be used such indicators as its area and profile height. Ultrasound echography permits to detect interosseous membrane tissue strain in case of forearm rotation and external compression in interosseous space, due to which its elasticity is evaluated.

Calcification in caval membrane causing primary Budd-Chiari syndrome: CT demonstration

We report two cases of membranous obstruction of the inferior vena cava (MOIVC) in which we observed patchy calcification in the membrane. The location of the calcification in the membrane was confirmed histologically. This finding was found histologically in four of eight cases of MOIVC, and it is a useful finding in the CT diagnosis of MOIVC.

Pseudomembranes in reflux esophagitis

Three cases are presented in which double-contrast esophagograms revealed one or more plaquelike lesions in the distal esophagus, representing pseudomembrane formation in patients with severe reflux esophagitis. Although to our knowledge this finding has not been reported previously in the radiologic literature, pseudomembranes have been documented endoscopically in patients with reflux esophagitis and biopsy-proved Barrett esophagus. Radiologists should be aware of this finding, since these pseudomembranes may be indistinguishable radiographically from plaquelike carcinomas arising in Barrett esophagus.

Computerized tomography studies of congenital and acquired cerebral intraventricular membranes. Report of two cases

The role of intraventricular membranes in recurrent shunt failure is explored in two cases using computerized tomography (CT) with intraventricular metrizamide and air ventriculography. One patient who had hydrocephalus with congenital intraventricular membranes containing neurons had a good ultimate response, although he had undergone seven shunt revisions before the membranes were discovered. The other patient with postventriculitis membranes had a complicated course. The effects of shunt malposition and intraventricular antibiotic treatment are discussed. It is determined that certain clues from CT scans, plain film, and air ventriculography may indicate the presence of membranes contributing to repeated shunt failure and that the use of intraventricular metrizamide with CT facilitates the diagnosis.

Bronchial foreign body of unusual mode of entry

A metallic bronchial foreign body whose mode of entry was through a puncture wound of the left cricothyroid membrane is recorded. Bronchoscopic aspiration was first done primarily to relieve severe dyspnea and six days later extraction of the foreign body was successfully performed.