What is the role of titin in active muscle?

Several properties of muscle defy explanation solely based on the sliding filament-swinging cross-bridge theory. Indeed, muscle behaves as though there is a dynamic "spring" within the sarcomeres. We propose a new "winding filament" mechanism for how titin acts, in conjunction with the cross-bridges, as a force-dependent spring. The addition of titin into active sarcomeres resolves many puzzling muscle characteristics.     

What is the role of bone scintigraphy in the diagnosis of infected joint prostheses?

AIM: To analyse the role played by bone scintigraphy in the diagnosis of infected joint prostheses. METHODS: The study included 77 patients, aged 32-77 years, in whom infection of a joint prosthesis (48 hip, 29 knee) was suspected. In all patients the following examinations were performed consecutively: a two-phase Tc methylene diphosphonate (Tc-MDP) bone scan, a Tc hexamethylproplyene amine oxime (Tc-HMPAO) labelled white blood cell (WBC) scan, and a Tc microcolloid bone marrow (BM) scan. The minimum interval between examinations was 48 h. The diagnoses were based on data obtained from bacteriological cultures. RESULTS: The bone scan was positive in all patients and 28 of them had an infection (sensitivity 100%, specificity 0%). The WBC scan was positive in 61 patients but only 27 had an infection. The WBC scan was negative in 16 patients, and the possibility of infection was discarded in 15 of these cases (sensitivity 96%, specificity 30%). The results of the bone marrow scan were not compatible with those of the WBC scan (suggestive of infection) in 27 patients: 26 of them had prosthesis infection. The results of both examinations were compatible in the other 34 patients and the possibility of infection was discarded in 33 of these patients (sensitivity 92.8%, specificity 98%). The addition of a BM scan to a WBC scan decreased the sensitivity from 96% to 92.8% but increased specificity from 30% to 98%. The addition of a bone scan to this dual combination did not alter the results. CONCLUSIONS: When infection of a prosthesis is suspected the diagnostic procedure should start with a WBC scan followed, if positive, by a BM scan. This procedure reduces the cost, the time required for a diagnosis, and the dose of radiation received by the patient.     

What is the clinical role of non-invasive atherosclerosis imaging?

Non-invasive atherosclerosis findings have been demonstrated to provide incremental diagnostic and predictive values for ischemia, acute coronary syndrome, and cardiovascular outcomes. The challenge is to translate research findings to a clinical role. Here, we review the current utility of atherosclerotic imaging and the incremental value of plaque imaging. We also evaluate future clinical and research implications for three patient populations: asymptomatic prevention, stable chest pain, and acute chest pain.     

What is the role of calcium scoring in the age of coronary computed tomographic angiography?

Non-contrast-enhanced CT for coronary artery calcification (CAC) as a marker of coronary atherosclerosis has been studied extensively in the primary prevention setting. With rapidly evolving multidetector CT technology, contrast-enhanced coronary CT angiography (CCTA) has emerged as the non-invasive method of choice for detailed imaging of the coronary tree. In this review, we systematically evaluate the role of CAC testing in the age of CCTA in both asymptomatic and symptomatic patients, across varying levels of risk. Although the role of CAC testing is well established in asymptomatic subjects, its use in evaluating those with stable symptoms that represent possible obstructive coronary artery disease is controversial. Nevertheless, available data suggest that in low-to-intermediate risk symptomatic patients, CAC scanning may serve as an appropriate gatekeeper to further testing with either CCTA (if no or only mild CAC present) versus functional imaging or invasive coronary angiography (when moderate or severe CAC present). Given the strong short-term prognostic value of CAC?=?0, studies are needed to further evaluate the role of CAC scanning in low-risk patients with acute chest pain presenting to the emergency room.     

What is the role of plain radiography in patients with foreign bodies in the gastrointestinal tract?

Foreign bodies (FBs) in the gastrointestinal (GI) tract can show a wide range of clinical manifestations ranging from spontaneous evacuation to severe complication. Plain radiography is a straightforward and important initial imaging modality in cases of FB ingestion or insertion and is also helpful for follow-up purposes. Careful evaluations of the plain radiographs can determine the presence and nature of FBs, and help predict their precise locations and facilitate risk assessment. In this review, a wide variety of FBs in the GI tract are illustrated, and the role of plain radiography in patient management is discussed.     

What is the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after CT?

The objective of our study was to estimate the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after abdominoplevic CT. A total of 104 patients initially underwent abdominopelvic CT before appendix US due to acute abdominal pain. All CT examinations were evaluated retrospectively for the presence of acute appendicitis. The findings of appendix on CT were classified into five categories (definite appendicitis, probably appendicitis, equivocal CT findings for diagnosis of appendicitis, probably not appendicitis, and normal looking appendix). Appendix US images and their radiologic reports were also evaluated retrospectively. Then, CT and US findings were correlated with clinical or pathologic diagnosis. Three all patients with definite appendicitis initially on CT again showed US findings of appendicitis. In the 32 patients of probably appendicitis on CT, US showed normal looking appendix in seven patients (21.8%, 7 of 32) who improved with medical treatment and discharged. In the 16 patients of equivocal CT findings for diagnosis of appendicitis, US showed appendicitis in seven patients (43.8%, 7 of 16) and normal looking appendix in nine patients. In the 12 patients of probably not appendicitis on CT, US showed acute appendicitis in two patients (16.7%, 2 of 12). In the 41 patients of normal looking appendix on CT, US showed acute appendicitis in five patients (12.2%, 5 of 41). US reevaluation enables us to avoid misdiagnosis of appendicitis on CT and improve diagnostic accuracy of acute appendicitis.     

Assessment of chest pain in the emergency room: What is the role of multidetector CT?

Chest pain is one of the most frequent complaints for patients seen in the emergency department. The current article describes the clinical stratification of patients who present to the emergency department with chest pain and discusses imaging options and analysis for these patients. It reviews conventional imaging approaches to assessing chest pain including chest radiography and stress testing. The main discussion focuses on the potential utility use of cross-sectional imaging, particularly multidetector CT, in the evaluation of chest pain in the emergency department.     

Adult celiac disease: What is the role of MRI?

PURPOSE: To evaluate the ability of MRI to identify intra- and extraintestinal findings of celiac disease in an adult population. MATERIALS AND METHODS: Forty-one subjects (18 men and 23 women; mean age = 41.3 years; 31 with biopsy-proven celiac disease, and 10 healthy volunteers) underwent MRI of the small bowel. MR studies were performed on a 1.5-T magnet using T2-weighted half-Fourier single-shot turbo spin-echo (HASTE) and true fast imaging in steady-state precession (True-FISP) sequences. The MR features and sensitivity, and the specificity and accuracy of some of these features are described. RESULTS: In the 31 celiac patients, MRI showed bowel dilatation in 61.3% (N = 19), increased number of ileal folds in 48.4% (N = 15), reversed fold pattern abnormality in 38.7% (N = 12), increased wall thickness in 16.1% (N = 5), duodenal stenosis in 6.5% (N = 2), intussusception in 12.9% (N = 4), mesenteric lymphadenopathy in 41.9% (N = 13), mesenteric vascular changes in 22.6% (N = 7), ascites in 6.5% (N = 2), and no abnormalities in 12.9% (N = 4). The volunteers had unremarkable exams. The overall specificity and accuracy were 100%, and sensitivity was 79% and 75% for increased number of ileal folders and reversed fold pattern abnormality, respectively. CONCLUSION: MRI is able to demonstrate intra- and extraintestinal features that may lead to the diagnosis of celiac disease in adults.     

Reflections on the role of consultant radiographers in the UK: What is a consultant radiographer?

ContextThis paper is the second paper from a two year in depth case study, exploring the role of consultant radiographers in the UK.MethodsA longitudinal case study approach was used to determine the role of consultant radiographers. Interviews were used to explore experiences of being a consultant, which were analysed using thematic analysis.Eight consultant radiographers participated (Note, two of the consultants withdrew after the first interview due to workload). Therefore two consultants were interviewed only once. The remaining six consultants were interviewed twice over a 12 month period.FindingsThe data presented in this paper explores the nature of the role, differences between roles, the four domains of practice, and how the role fits into local organisational structures.The study shows wide variation in the types of roles undertaken, reflecting that the creation of these roles were in response to local clinical need and often related to an individual practitioner's skills. The broad scope of the role was shown across all the consultants, with evidence of roles developing into new areas of service delivery.ConclusionsThe paper offers insight into the role(s) of consultant radiographers in the UK. The range and scope of their practice is extensive, with much variation. It is evident that the clinical aspect of the role dominates, with research being the least supported domain of practice. There remains a lack of clarity around the role, with concerns about remuneration and other limitations that may restrict the role developing further.     

What is the significance of haemosiderin in the lungs of deceased infants?

In infants, pulmonary haemosiderin has been put forward as a marker of previous asphyxic abuse and possible grounds for suspicion of homicide. Review of the available literature does not provide a strong enough evidence base to support this claim. Further research is needed before instigation of criminal proceedings can be justified on this pathological finding.     

What is the influence of surgical treatment of adolescent idiopathic scoliosis on postural control?

PurposeTo evaluate the effect of surgical treatment on the control of upright balance in adolescent idiopathic scoliosis (AIS).MethodsThirty adolescents were divided into two groups: Group C (n = 15) consisted of individuals without scoliosis (control), and Group S (n = 15) consisted of individuals with scoliosis. The mean amplitude and velocity of the center of pressure (COP) evaluations in the anterior-posterior and medial-lateral directions were obtained before surgery and at 7, 30, 60 and 90-days after surgery, in an upright position, using a force platform.ResultsGroup S showed larger oscillation than Group C before surgery. The COP oscillation in Group S after surgery was larger than that in the pre-surgery period. The oscillation diminished over the post-surgery period, but individuals in the 90-day post-surgery period still had larger oscillation compared with the oscillation in the pre-surgery period.ConclusionGroup S had larger AP and ML mean amplitude and mean velocity before and after surgery compared with Group C, which suggests that a sensorimotor impairment or sensory integration problem could explain the balance control alterations more than biomechanical factors in the AIS.