Musculoskeletal Injuries in Cross-Country Skiing.

Cross-country skiing, one of the oldest forms of skiing, is enjoyed widely as a recreational activity and as a competitive sport. It is practiced in regions with snow-covered landscapes, particularly in the Nordic countries and with increasing popularity in non-Nordic countries of Europe as well as in the United States, Canada, Australia, and New Zealand, among others. Cross-country skiing is a fairly safe activity, and historically the risk of injury has been relatively low. However, advances in equipment development, together with increasing speeds, more demanding trails, and growing numbers of participants, have all contributed to a larger report of injuries, although still comparatively low versus other skiing modalities. Injuries in cross-country skiing can occur either after a single traumatic event or in the setting of chronic repetitive microtrauma (i.e., overuse injuries).

Knee Ligament Imaging: Preoperative and Postoperative Evaluation.

Preoperative and postoperative imaging of knee ligament injury hinges on the appropriate use of available modalities. Knowledge of injury patterns as well as the surgical significance of certain image findings enhances injury detection and supports appropriate preoperative planning. The radiologist must be familiar with the strengths and weaknesses of each modality for evaluating specific aspects of ligamentous pathology. This article focuses on preoperative and postoperative imaging of knee ligament injury. Basic topics pertaining to preoperative image modality selection and isolated injury detection are addressed. More advanced areas including ligamentous injury patterns, surgical indications, and postoperative imaging are also discussed.

Diagnostic and management challenges for MDM2-, CDK4-negative fatty tumors of the retroperitoneum.

BACKGROUND: Neoplasms of the retroperitoneum that contain a major fat component may represent either benign entities, such as lipomas or angiomyolipomas, or malignancy such as liposarcoma. Distinguishing these diagnoses has important implications for management. While liposarcomas often stain positively for MDM2 and CDK4 proteins, absence of these markers can lead to diagnostic and management challenges. METHODS: We examined three cases in our institution of fat-containing masses of the retroperitoneum that lacked MDM2 and CDK4 markers to highlight the challenges in diagnosing and managing these cases. A thorough review of the literature examining radiologic and histologic features that can be used to determine that diagnosis was conducted and summarized. RESULTS: The three cases we present represent the three main diagnostic entities that can be found in among fatty tumors of the retroperitoneum: lipoma, angiomyolipoma, and liposarcoma. While radiologic features and analysis of histology helped to inform management, these cases in conjunction with the literature also illustrate the limitations of the diagnostic work up and importance also factoring the biologic behavior of the tumor in its management. CONCLUSION: Fat-containing tumors of the retroperitoneum that do not stain for MDM2 or CDK4 can pose a diagnostic challenge. Assessing radiologic and pathologic features in conjunction with the biologic behavior of these tumors should inform their management.

Improvement of ethanol production by extractive fed-batch fermentation in a drop column bioreactor.

The use of fed-batch extractive fermentation can overcome inhibitory effects caused by the substrate and ethanol to the yeast cells, since it allows regulate the substrate concentration and remove the product as it is produced. The present study describes the modelling and experimental validation of ethanol production in fed-batch extractive fermentation with in situ ethanol removal by oleic acid in a non-conventional drop column bioreactor (DCB) operated under industrial conditions. The model developed using the hybrid Andrews-Levenspiel equation and ethanol distribution coefficient parameter (KDE) provided an excellent description of the fed-batch extractive ethanol fermentation process with oleic acid. Furthermore, extractive fed-batch fermentation allowed the feed up to 306.6 kg m-3 of substrate (total reducing sugars), with total ethanol concentration in extractive fermentation in the ranging 100.3-139.8 kg m-3 (12.7-17.7 ºGL), 19.9-67.2% higher when compared with the conventional process without ethanol removal. Moreover, this process has the advantage of less effluent generated and energy consumption for ethanol recovery when compared to the conventional process.

Resolution of Osseous Sarcoidosis with Methotrexate.

Though a relatively uncommon manifestation of sarcoidosis, some clinicians are tasked with managing osseous involvement of disease, and the optimal treatment approach in this setting is not well established. Previous studies have shown variable efficacy for osseous sarcoidosis utilizing multiple agents alone or in combination, often using imaging follow-up in conjunction with clinical assessment to evaluate response to treatment. We present a case of widespread skeletal involvement of sarcoidosis without evidence of concurrent pulmonary disease demonstrating marked clinical improvement and near-complete resolution of imaging abnormalities on magnetic resonance imaging (MRI) following the use of methotrexate as the primary pharmacologic agent.

Multifactorial pathological hip subluxation in neurofibromatosis type-1 (NF1) due to intra-articular plexiform neurofibroma, lumbar radiculopathy and neurofibromatous polyneuropathy.

Neurofibromatosis type-1 (NF1) is a multisystem disorder with very rare descriptions of hip instability. We report a case of a 37-year-old man with known NF1 and childhood-onset of left foot drop, who developed persistent left hip pain following a minor trauma. Physical examination revealed left-sided mild foot drop, hip abductor weakness, bilateral sensory loss in feet and an antalgic gait. Work-up revealed anterolateral subluxation of the left femoral head along with left hip plexiform neurofibroma (PN), dysplastic and degenerative changes, neurofibromatous neuropathy and chronic left L5 radiculopathy. Initial improvement after surgical resection of the PN was unsustained and followed by increasing pain and recurrent hip subluxation, prompting a total hip arthroplasty which resulted in marked improvement of symptoms. Our patient, unlike those in other reports, illustrates multiple aetiologies of hip dislocation in NF1 including local factors, lumbar radiculopathy and polyneuropathy, reinforcing the importance of a multidisciplinary approach in the management of such cases.

Comprehensive review of the anatomy, function, and imaging of the popliteus and associated pathologic conditions.

The popliteus is a relatively small but unique muscle of the knee. It is a component of the posterolateral corner of the knee and acts as a major stabilizer of the posterolateral knee. It is important to be aware of the normal magnetic resonance (MR) imaging appearance of the popliteus musculotendinous complex and its relation to other structures of the posterolateral corner for accurate diagnosis. It is also important to be aware of the pitfalls in imaging of the popliteus. Dysfunction of the popliteus is often underappreciated and is usually secondary to direct or indirect trauma. Injuries of the popliteus can be classified as first-, second-, or third-degree strains. Injuries of the popliteus are often associated with other posterolateral corner injuries. Pathologic conditions of the popliteus may be a clue to other injuries in the knee. The site and pattern of popliteus tear can be helpful to the orthopedic surgeon in deciding whether repair is warranted and determining the approach to surgery and has prognostic implications. Undiagnosed popliteus injuries can lead to poor functional results after knee reconstructive surgery. Inflammatory pathologic conditions of the popliteus may cause knee pain and can be diagnosed with MR imaging. The popliteus is an important component of the posterolateral corner that needs closer attention for optimal diagnosis and patient care.

Evaluation of the bioremoval of Cr(VI) and TOC in biofilters under continuous operation using response surface methodology.

In the present study, the bioremoval of Cr(VI) and the removal of total organic carbon (TOC) were achieved with a system composed by an anaerobic filter and a submerged biofilter with intermittent aeration using a mixed culture of microorganisms originating from contaminated sludge. In the aforementioned biofilters, the concentrations of chromium, carbon, and nitrogen were optimized according to response surface methodology. The initial concentration of Cr(VI) was 137.35 mg l(-1), and a bioremoval of 85.23% was attained. The optimal conditions for the removal of TOC were 4 to 8 g l(-1) of sodium acetate, >0.8 g l(-1) of ammonium chloride and 60 to 100 mg l(-1) of Cr(VI). The results revealed that ammonium chloride had the strongest effect on the TOC removal, and 120 mg l(-1) of Cr(VI) could be removed after 156 h of operation. Moreover, 100% of the Cr(VI) and the total chromium content of the aerobic reactor output were removed, and TOC removals of 80 and 87% were attained after operating the anaerobic and aerobic reactors for 130 and 142 h, respectively. The concentrations of cells in both reactors remained nearly constant over time. The residence time distribution was obtained to evaluate the flow through the bioreactors.

Evaluation of hexavalent chromium removal in a continuous biological filter with the use of central composite design (CCD).

Hexavalent chromium is frequently found in industrial effluents as a result of the industrial applications of this compound and its anti-corrosive features. However, hexavalent chromium is extremely toxic, and its discharge in water is regulated, with a maximum limit of 0.1 mg/L in accordance with legislation established by CONAMA-Brazil (no. 397, April 3, 2008). To achieve lower discharge values, it is necessary to reduce from Cr(VI) to Cr(III), which is less toxic, and an economic alternative involves biological removal of this compound. Residence time distributions (RTDs) were measured to evaluate the behavior of actual biofilter operation conditions in a biofilter flow. The medium residence time distributions used were 8 and 24 h (recommended by the legislation). To optimize this process, a central composite design was used, considering the initial chromium concentration and pH as the independent variables and the removal of hexavalent chromium as the response. The boundary curves and surface response showed optimal behavior at 3.94 mg/L [Cr(0)] and a pH of 6.2. The removal process of hexavalent chromium is mathematically described by the Michaelis-Menten kinetic model. This model appropriately represents the variation of chromium concentration along the bioreactor.

Appearance of the delta phalanx (longitudinally bracketed epiphysis) with MR imaging.

The delta phalanx is an unusual condition occurring in the hand or the foot that can be distinguished from a secondary ossification center on radiographic evaluation based on the well-defined phalangeal epiphyses typically evident by 24-30 months of age. MR imaging of the delta phalanx offers the advantage of visualizing sites of unossified bone before the age these findings are typically visible with radiography. We describe the case of a 15-month-old boy who presented with soft-tissue fusion of the third and fourth digits of the right hand. Radiograph and MR evaluation revealed soft-tissue intra-axial syndactyly of the third and fourth digits and a delta phalanx involving the proximal phalanx of the involved fourth digit.

Development of a wearable vital signs monitor for healthcare.

In development countries the vital signs data measurement normally is performed at hospitals or laboratories where patients remain under observation with many electrodes attached on the body. The integration of biomedical data acquisition systems and information technologies (IT) enables continuous real time monitoring of physiological data in daily life, which improves patient's medical care and medical research possibilities. To achieve this goal, the research and development of some wearable intelligent sensors, sensors miniaturization, signal processing, wireless transmission, and databases development for these vital data have been done. Our goal is to implement a wearable system that can be used in places located outside of hospitals and medical institutions coverage area. In this paper, we present the current stage of the project where some intelligent modules have been implemented and other are under construction. Preliminary results concerning Non-Invasive Blood Pressure (NIBP), ECG and wireless connection are also presented.

Imaging appearances of the sternum and sternoclavicular joints.

The sternum and sternoclavicular joints--critical structures of the anterior chest wall--may be affected by various anatomic anomalies and pathologic processes, some of which require treatment. Pectus excavatum and pectus carinatum are common congenital anomalies that are usually benign but may warrant surgical treatment if they cause compression of vital internal structures. By contrast, developmental variants such as the sternal foramen are asymptomatic and do not require further evaluation or treatment. Arthritides of the sternoclavicular joint (osteoarthritis, septic arthritis, and seronegative arthropathies) are common and must be differentiated before an appropriate management method can be selected. The recognition of complications of sternotomy (eg, sternal dehiscence, secondary osteomyelitis) is critical to avoid life-threatening sequelae such as acute mediastinitis. Likewise, the detection of sternal fractures and sternoclavicular dislocations is important, especially where they impinge on vital structures. In addition, sternal malignancies (most commonly, metastases and chondrosarcoma) must be distinguished from benign neoplasms. To achieve accurate and timely diagnoses that facilitate appropriate treatment, radiologists must be familiar with the appearances of these normal anatomic variants and diseases of the sternum.

The diaphragmatic crura and retrocrural space: normal imaging appearance, variants, and pathologic conditions.

The retrocrural space (RCS) is a small triangular region within the most inferior posterior mediastinum bordered by the two diaphragmatic crura. Multiplanar imaging modalities such as computed tomography and magnetic resonance imaging allow evaluation of the RCS as part of routine examinations of the chest, abdomen, and spine. Normal structures within the retrocrural region include the aorta, nerves, the azygos and hemiazygos veins, the cisterna chyli with the thoracic duct, fat, and lymph nodes. There is a wide range of normal variants of the diaphragmatic crura and of structures within the RCS. Diverse pathologic processes can occur within this region, including benign tumors (lipoma, neurofibroma, lymphangioma), malignant tumors (sarcoma, neuroblastoma, metastases), vascular abnormalities (aortic aneurysm, hematoma, azygos and hemiazygos continuation of the inferior vena cava), and abscesses. An understanding of the anatomy, normal variants, and pathologic conditions of the diaphragmatic crura and retrocrural structures facilitates diagnosis of disease processes within this often overlooked anatomic compartment.

Intramural hematoma of the esophagus: a pictorial essay.

Intramural hematoma of the esophagus (IHE) is a rare but well-documented condition that is part of the spectrum of esophageal injuries which includes the more common Mallory-Weiss tear and Boerhaave's syndrome. Acute retrosternal or epigastric pain is a common clinical feature, which can be accompanied by dysphagia, odynophagia, or hematemesis. An early differentiation from Mallory-Weiss tear, Boerhaave syndrome, ruptured aortic aneurysm, aortic dissection, acute myocardial infarction, or pulmonary pathology can be difficult. Computed tomography (CT) is the imaging modality of choice and characteristically reveals a concentric or eccentric thickening of the esophageal wall with well-defined borders and variable degree of obliteration of the lumen. Measurement of the attenuation values within the lesion will reveal blood density which varies according to the age of the hematoma. CT should be considered the preferred diagnostic technique, thereby facilitating proper clinical management. Early diagnosis is crucial as most patients may be treated conservatively with good outcome.

Imaging findings in cardiac tamponade with emphasis on CT.

Cardiac tamponade is a life-threatening condition that results from slow or rapid heart compression secondary to accumulation of fluid, pus, blood, gas, or tissue within the pericardial cavity. This condition can be associated with multiple causes including trauma, inflammation, scarring, or neoplastic involvement of the pericardial space among others. The main pathophysiologic event leading to tamponade is an increase in intrapericardial pressure sufficient to compress the heart with resultant hemodynamic impairment, which leads to limited cardiac inflow, decreased stroke volume, and reduced blood pressure. These events result in diminished cardiac output, which manifests clinically as a distinctive form of cardiogenic shock. Although cardiac tamponade is a clinical diagnosis, imaging studies play an important role in assessment and possible therapeutic intervention. Computed tomographic (CT) findings associated with cardiac tamponade include pericardial effusion, usually large, with distention of the superior and inferior venae cavae; reflux of contrast material into the azygos vein and inferior vena cava; deformity and compression of the cardiac chambers and other intrapericardial structures; and angulation or bowing of the interventricular septum. Familiarity with the clinical and pathophysiologic features of cardiac tamponade and correlation with the associated CT findings are essential for early and accurate diagnosis.

Imaging manifestations of Kaposi sarcoma.

Kaposi sarcoma (KS) is a low-grade vascular tumor that typically manifests as one of four variants: classic KS, endemic (African) KS, iatrogenic (organ transplant-related) KS, or acquired immunodeficiency syndrome (AIDS)-related KS. Several clinical and epidemiologic differences have been noted among these variants. Classic KS and endemic KS rarely require radiologic evaluation due to their usually chronic course and stability of skin compromise. However, iatrogenic KS and AIDS-related KS, the most common forms of the disease, are frequently disseminated or symptomatic and may thus require imaging studies for both diagnosis and staging. KS is the most common tumor among AIDS patients, affecting a high percentage of these individuals, and is considered to be an AIDS-defining illness. Multiple organs can be involved by AIDS-related KS. KS has been linked with human herpes virus type 8 infection and other cofactors. Although pulmonary, gastrointestinal, and skin involvement by KS has previously been described, this tumor can affect multiple organs, generating a wide spectrum of imaging findings and pathologic correlates. It is important for the radiologist to be familiar with this spectrum of imaging manifestations and corresponding pathologic findings.

Cardiovascular complications of human immunodeficiency virus infection.

The heart and great vessels are not the sites most frequently affected by opportunistic infections and neoplastic processes in patients with acquired immune deficiency syndrome (AIDS). However, cardiovascular complications occur in a significant number of such patients and are the immediate cause of death in some. The spectrum of cardiovascular complications of AIDS that may be depicted at imaging includes dilated cardiomyopathy, pericardial effusion, human immunodeficiency virus-associated pulmonary hypertension, endocarditis, thrombosis, embolism, vasculitis, coronary artery disease, aneurysm, and cardiac involvement in AIDS-related tumors. To aid accurate diagnosis and appropriate treatment planning, radiologists should be familiar with the imaging appearance of each of these complications.

CT and MR imaging findings of malignant cardiac tumors.

This article reviews CT and MRI features of malignant cardiac and pericardial tumors, most of which originate from the lung, breast, melanoma, leukemia, or lymphoma through lymphatic, hematogenous, transvenous, and direct pathways. Although echocardiography establishes the diagnosis in most cases, CT and MRI provide additional physical, spatial, and functional information that further aids the evaluation of metastases. For instance, CT provides superior resolution for detecting calcification or fat, while MRI with its direct multiplanar ability more completely characterizes the heart, pericardium, mediastinum, and lungs. MRI also helps elucidate the pathophysiological effects of these tumors on cardiac function through gated cine-loop sequences. Beyond tumor characterization, both modalities can help confirm diagnosis through the addition of contrast, which helps distinguish tumor from myocardium, thrombus, and blood flow artifact. Ultimately, MRI best facilitates surgical planning and posttreatment follow-up in large part because of its unparalleled ability to locate and delimit these tumors.

CT and MR imaging findings of benign cardiac tumors.

This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rare, benign tumors outnumber their primary malignant counterparts three to one. Since mortality varies directly with invasion, identifying the neoplasm at an early stage helps focus treatment, especially in benign cases, which generally respond well to surgical resection. In adults and children, myxomas and rhabdomyomas, respectively, represent the most common benign tumors, which can be grouped into tissue-specific subtypes, such as rhabdomyomas, fibromas, lipomas, teratomas, etc. Besides their variable prevalence in particular age groups, these tumors also differ with regard to their gender predilection, location, and number. For example, myxomas appear predominantly in women and generally as a solitary mass in the left or right atrium, whereas rhabdomyomas present equally in boys and girls and chiefly as multiple masses in the ventricles. Despite their differences, however, both types share an association with heritable syndromes like the Carney complex for myxomas and tuberous sclerosis for rhabdomyomas. As with all cardiac tumors, echocardiographic findings usually suggest the initial diagnosis but cross-sectional imaging with CT and MRI can help resolve diagnostically challenging cases. For example, with its direct multiplanar capability, excellent contrast resolution, and large field of view, MRI permits a detailed examination of the entire mediastinum, helping to rule out an equivocal mass on echocardiography. Through dynamic techniques, MRI, in addition to morphologic characterization, can depict the pathophysiological effects of these tumors, for instance, with regard to myocardial contraction, valvular function, or blood flow.