Pseudotumor in metal-on-metal hip arthroplasty: a comparison study of three grading systems with MRI.

OBJECTIVE: Pseudotumors, a well-known complication of metal-on-metal total hip arthroplasty (MoM THA), are well identified on metal artifact-reducing sequences magnetic resonance imaging (MARS-MRI). Several MRI grading systems are described in the orthopedic literature, but their validity is unknown in large clinical studies. Our study was undertaken to describe the classification of pseudotumors in a preselected cohort divided into high- and low-risk patients, using three pseudotumor grading systems applied on MARS-MRI, and to determine the interobserver reliability of the grading systems. PATIENTS AND METHODS: A retrospective study was performed on 377 consecutive patients (240 MRI scans) treated with an M2a-38 and Taperloc stem combination (Biomet, Warsaw, IN, USA). Patients were divided into a high-risk and a low-risk group based on previous published risk factors. Two observers determined the presence of pseudotumors using three different pseudotumor grading systems for classifying MARS-MRI results. RESULTS: The prevalence of pseudotumors as determined with MARS-MRI was 59% in our high-risk group, 0% in the low-risk group and 43% in the control group. Serum cobalt values were increased in the high-risk group. The kappa values of the Anderson, Hauptfleisch and Matthies grading system scores were 0.43, 0.44, and 0.49 respectively. CONCLUSIONS: High-risk patients are at a high risk for pseudotumor development. No pseudotumor development was found in low-risk patients. Interobserver reliability scored best with the Matthies system, but all three grading systems showed only a moderate agreement.

Improving hybrid image and structure-based deformable image registration for large internal deformations.

Objective.Deformable image registration (DIR) is a widely used technique in radiotherapy. Complex deformations, resulting from large anatomical changes, are a regular challenge. DIR algorithms generally seek a balance between capturing large deformations and preserving a smooth deformation vector field (DVF). We propose a novel structure-based term that can enhance the registration efficacy while ensuring a smooth DVF.Approach.The proposed novel similarity metric for controlling structures was introduced as a new term into a commercially available algorithm. Its performance was compared to the original algorithm using a dataset of 46 patients who received pelvic re-irradiation, many of which exhibited complex deformations.Main results.The mean Dice Similarity Coefficient (DSC) under the improved algorithm was 0.96, 0.94, 0.76, and 0.91 for bladder, rectum, colon, and bone respectively, compared to 0.69, 0.89, 0.62, and 0.88 for the original algorithm. The improvement was more pronounced for complex deformations.Significance.With this work, we have demonstrated that the proposed term is able to improve registration accuracy for complex cases while maintaining realistic deformations.

Deep Learning for Radiotherapy Outcome Prediction Using Dose Data - A Review.

Artificial intelligence, and in particular deep learning using convolutional neural networks, has been used extensively for image classification and segmentation, including on medical images for diagnosis and prognosis prediction. Use in radiotherapy prognostic modelling is still limited, however, especially as applied to toxicity and tumour response prediction from radiation dose distributions. We review and summarise studies that applied deep learning to radiotherapy dose data, in particular studies that utilised full three-dimensional dose distributions. Ten papers have reported on deep learning models for outcome prediction utilising spatial dose information, whereas four studies used reduced dimensionality (dose volume histogram) information for prediction. Many of these studies suffer from the same issues that plagued early normal tissue complication probability modelling, including small, single-institutional patient cohorts, lack of external validation, poor data and model reporting, use of late toxicity data without taking time-to-event into account, and nearly exclusive focus on clinician-reported complications. They demonstrate, however, how radiation dose, imaging and clinical data may be technically integrated in convolutional neural networks-based models; and some studies explore how deep learning may help better understand spatial variation in radiosensitivity. In general, there are a number of issues specific to the intersection of radiotherapy outcome modelling and deep learning, for example translation of model developments into treatment plan optimisation, which will require further combined effort from the radiation oncology and artificial intelligence communities.

Identification of subcutaneous myiasis using bedside emergency physician performed ultrasound.

BACKGROUND: Subcutaneous myiasis, a maggot infiltration of human tissue, is common in tropical countries. However, physicians in the United States may be unlikely to consider this etiology of dermatologic abnormalities even when a travel history suggests the diagnosis should be included in the differential. CASE REPORT: We report the case of a patient who returned from Sierra Leone with an infestation of a maggot of Cordylobia anthropophaga (tumbu fly) that was diagnosed and appropriately treated based on ultrasound findings. CONCLUSION: As international travel increases, clinicians should maintain a high level of suspicion for tumbu fly infestation in returned travelers from endemic areas. The increasing use of ultrasound in the Emergency Department for evaluation of skin and soft tissue infections may aid the physician in making the diagnosis of subcutaneous myiasis.

[A 51-year-old woman with upper abdominal pain]. / Een 51-jarige vrouw met pijn in de bovenbuik.

A 51-year-old woman presented to the emergency room with upper abdominal pain and elevated infection parameters. No abnormalities were found during gastroscopy. A CT scan demonstrated perigastricappendagitis. Perigastricappendagitis is a rare infarction of a fatty appendix of the perigastric ligaments. It is a benign and self-limiting disease.

Identification and separation of rigid image registration error sources, demonstrated for MRI-only image guided radiotherapy.

PURPOSE: Rigid image registration (RIR) accuracy is crucial for image guided radiotherapy (IGRT). However, existing clinical image registration assessment methods cannot separate and quantify RIR error sources. Herein, we develop an extension of the 'full circle method' for RIR consistency. Paired registration circuits are used to isolate sources of RIR error caused by reference dataset substitution, from those inherent to the underlying RIR. This approach was demonstrated in the context of MRI-only IGRT, assessing substitution of MRI-derived synthetic-CT (sCT) for conventional CT, in a cohort of rectal cancer patients. MATERIALS AND METHODS: Planning CT, MRI-derived sCT, and two CBCTs from seven rectal cancer patients were retrospectively registered with global and soft tissue clipbox based RIR. Paired registration circuits were constructed using two moving (cone beam CT) images and two reference images (CT and sCT), per patient. Differences between inconsistencies in registration circuits containing CT and sCT were used to determine changes in registration accuracy due to substitution of sCT for CT. RESULTS: sCT was found to be equivalent to CT under global RIR, with median differences of 0.05 mm and 0.01°. Soft tissue clipbox based RIR with sCT exhibited gross misregistration (>5 mm or 3°) for 3 patients. Registration consistency was degraded compared to CT across the cohort, with median differences of 0.54 mm and 0.15°. CONCLUSION: A paired registration circuit methodology for assessing RIR accuracy without ground truth information was developed and demonstrated for MRI-only IGRT in rectal cancer. This highlighted a reduction in clipbox based RIR consistency when sCT was substituted for conventional CT. The developed method enabled separation of degraded registration accuracy, from other error sources within the overall registration inconsistency. This novel methodology is applicable to any RIR scenario and enables analysis of the change in RIR performance on modification of image data or process.

New ligands for melanocortin receptors.

Named originally for their effects on peripheral end organs, the melanocortin system controls a diverse set of physiological processes through a series of five G-protein-coupled receptors and several sets of small peptide ligands. The central melanocortin system plays an essential role in homeostatic regulation of body weight, in which two alternative ligands, alpha-melanocyte-stimulating hormone and agouti-related protein, stimulate and inhibit receptor signaling in several key brain regions that ultimately affect food intake and energy expenditure. Much of what we know about the relationship between central melanocortin signaling and body weight regulation stems from genetic studies. Comparative genomic studies indicate that melanocortin receptors used for controlling pigmentation and body weight regulation existed more than 500 million years ago in primitive vertebrates, but that fine-grained control of melanocortin receptors through neuropeptides and endogenous antagonists developed more recently. Recent studies based on dog coat-color genetics revealed a new class of melanocortin ligands, the beta-defensins, which reveal the potential for cross talk between the melanocortin and the immune systems.

Gouty arthritis: decision-making following dual-energy CT scan in clinical practice, a retrospective analysis.

To establish whether dual-energy CT (DECT) is a diagnostic tool, i.e., associated with initiation or discontinuation of a urate lowering drug (ULD). Secondly, to determine whether DECT results (gout deposition y/n) can be predicted by clinical and laboratory variables. Digital medical records of 147 consecutive patients with clinical suspicion of gout were analyzed retrospectively. Clinical data including medication before and after DECT, lab results, and results from diagnostic joint aspiration and DECT were collected. The relationship between DECT results and clinical and laboratory results was evaluated by univariate regression analyses; predictors showing a p < 0.10 were entered in a multivariate logistic regression model with the DECT result as outcome variable. A backward stepwise technique was applied. After the DECT, 104 of these patients had a clinical diagnosis of gout based on the clinical judgment of the rheumatologist, and in 84 of these patients, the diagnosis was confirmed by demonstration of monosodium urate (MSU) crystals in synovial fluid (SF) or by positive DECT. After DECT, the current ULD was modified in 33 (22.4%) of patients; in 29 of them, ULD was started and in 1 it was intensified. Following DECT, the current ULD was stopped in three patients. In the multivariable regression model, cardiovascular disease (OR 3.07, 95% CI 1.26-7.47), disease duration (OR 1.008, 95% CI 1.001-1.016), frequency of attack (OR 1.23, 95% CI 1.07-1.42), and creatinine clearance (OR 2.03, 95% CI 0.91-1.00) were independently associated with positive DECT results. We found that the DECT result increases the confidence of the prescribers in their decision to initiation or discontinuation of urate lowering therapy regimen in of mono- or oligoarthritis. It may be a useful imaging tool for patients who cannot undergo joint aspiration because of contraindications or with difficult to aspirate joints, or those who refuse joint aspiration. We also suggest the use of DECT in cases where a definitive diagnosis cannot be made from signs, symptoms, and MSU analysis alone.

Perturbation of membrane microdomains reduces mitogenic signaling and increases susceptibility to apoptosis after T cell receptor stimulation.

Acid sphingomyelinase-deficient (asmase-/-) mice generated by gene targeting abundantly store sphingomyelin in the reticuloendothelial system of liver, spleen, bone marrow, and in brain. Liver cells of asmase-/- mice accumulate sphingomyelin and glycosphingolipids in purified lipid bilayers of microsomes, Golgi, and the plasma membrane, but cholesterol is depleted in the plasma membrane. Detergent-insoluble glycolipid-enriched membrane microdomains (GEM) can be isolated from hepatocytes, embryonic fibroblasts, and splenocytes of wild-type, but not of asmase-/- mice, by sucrose gradient density centrifugation. Lck and other Src-family kinases are reduced in isopycnic fractions of asmase-/- splenocytes compared to GEM-containing fractions of wild-type cells. The proliferation of asmase-/- T lymphocytes is reduced, whereas their susceptibility to Fas-induced apoptosis is increased after T cell receptor (TCR) stimulation. TNF receptor I signaling remains unimpaired. The perturbation of GEM impairs tyrosine phosphorylation and, consequently, mitogenic signaling of the TCR. Reduced MAPK activity-dependent FLICE-like inhibitory protein (FLIP) expression in asmase-/- T lymphocytes increases their sensitivity towards Fas-mediated apoptosis.

Analysis of persistent disease on the ear following Mohs surgery.

A retrospective study of 338 patients with malignant lesions of the auricle is presented. The results of treatment using Mohs microscopically controlled surgery and conventional surgical excision are compared and the high incidence of recurrence is stressed. The incidence, etiology, pathology, and subclinical extension of auricular tumors are discussed. The treatment of choice is Mohs microscopically controlled surgery and a plea is made for a more radical therapeutic approach to these often casually treated neoplasms.

Randomized clinical trial on the use of antispasmodic drugs in barium enema: impact on radiological practice.

PURPOSE: To assess the willingness of radiologists to change their practice when the results of a randomized clinical trial (RCT) on the use of antispasmodic drugs in barium enema are presented. MATERIALS AND METHODS: During the years 1994 and 1995 two postal questionnaires were sent to 481 practicing radiologists who were all members of the Netherlands Society of Radiology. In the first questionnaire the respondents were asked to give the characteristics of their practices in performing daily barium enema. The data from this questionnaire was used as a reference. The second questionnaire was sent to the respondents together with an abstract on the randomized clinical trial supporting the use of antispasmodic drugs in barium enema. We also indicated a preference for Buscopan over Glucagon as the antispasmodic drug. The willingness to change prescription habits was measured by comparing the data of the two questionnaires. RESULTS: Of 481 practicing radiologists, 312 responded to the first questionnaire and gave information of their prescription habits (response rate 64%). These 312 responders were sent an abstract of the RCT and were asked to fill out a second questionnaire to determine their willingness to change their practice. Two hundred and sixty-seven radiologists responded (response rate 86%). A significant number of 119 (51%) were willing to increase the use of antispasmodic drugs. A significant number of 128 (55%) chose to increase the use of Buscopan, while a significant number of 81 (32%) were willing to decrease the use of Glucagon. CONCLUSION: Direct exposure to the results of an RCT recommending the use of antispasmodic drugs in barium enema, especially Buscopan, is likely to increase its use by practicing radiologists.

Clinical and noninvasive assessment of venous disease as related to pulmonary embolism.

Proper management of patients with venous disease requires recognition of the various syndromes and an accurate objective diagnosis. Unfortunately many physicians are unfamiliar with the different venous disorders and are unaware of the fallibility of the clinical diagnosis of these syndromes. This article reviews the six common venous conditions that collectively are more common than coronary or peripheral arterial disease. Acute and recurrent deep vein thrombosis, postthrombotic syndrome, superficial thrombophlebitis, varicose veins, and pulmonary embolism may all confront the physician regardless of his or her specialty. Clinical recognition and differentiation of these disorders along with appropriate use of objective, noninvasive isotopic and venographic studies should lead to accurate diagnosis and management of these venous syndromes. Such an approach will permit prompt and appropriate therapy for disabling and potentially life-threatening venous thromboembolism while avoiding unnecessary anticoagulation of patients with disorders mimicking venous disease.

Collaborative preceptor training: a creative approach in tough times.

Rapid changes in the health care environment have challenged educators to find more efficient methods of developing nurses. These demands are leading to the use of collaborative approaches to education. Nurse educators have also found that they have to rely on preceptors for orientation of new employees. The Texas Medical Center Collaborative Preceptor Program was developed in 1989 to prepare nursing preceptors for all nine participating institutions. The goals of the program were to increase efficient use of instructor time, standardize preceptor preparation in the Texas Medical Center, and offer more programs and prepare more nurses per year than each individual institution could do alone. There were many unexpected benefits as well, and future plans for collaboration are already being formulated.

Acute adrenal insufficiency due to bilateral adrenal hemorrhage.

We report a rare case of bilateral hemorrhage of adrenal glands diagnosed in a 61-year-old female. The case presented with classic clinical findings and typical imaging features.

Photofragment slice imaging studies of pyrrole and the Xe...pyrrole cluster.

The photolysis of pyrrole has been studied in a molecular beam at wavelengths of 250, 240, and 193.3 nm, using two different carrier gases, He and Xe. A broad bimodal distribution of H-atom fragment velocities has been observed at all wavelengths. Near threshold at both 240 and 250 nm, sharp features have been observed in the fast part of the H-atom distribution. Under appropriate molecular beam conditions, the entire H-atom loss signal from the photolysis of pyrrole at both 240 and 250 nm (including the sharp features) disappear when using Xe as opposed to He as the carrier gas. We attribute this phenomenon to cluster formation between Xe and pyrrole, and this assumption is supported by the observation of resonance enhanced multiphoton ionization spectra for the (Xe...pyrrole) cluster followed by photofragmentation of the nascent cation cluster. Ab initio calculations are presented for the ground states of the neutral and cationic (Xe...pyrrole) clusters as a means of understanding their structural and energetic properties.

High resolution photofragment translational spectroscopy of the near UV photolysis of indole: dissociation via the 1pi sigma* state.

The fragmentation dynamics of indole molecules following excitation at 193.3 nm, and at a number of different wavelengths in the range 240 < or = lambda(phot) < or = 286 nm, have been investigated by H Rydberg atom photofragment translational spectroscopy. The longer wavelength measurements have been complemented by measurements of excitation spectra for forming parent and fragment ions by two (or more) photon ionisation processes. Analysis identifies at least three distinct contributions to the observed H atom yield, two of which are attributable to dissociation of indole following radiationless transfer from the 1pi pi* excited states (traditionally labelled 1L(b) and 1L(a)) prepared by UV single photon absorption. The structured channel evident in total kinetic energy release (TKER) spectra recorded at lambda(phot) < or = 263 nm is rationalised in terms of N-H bond fission following initial pi* <-- pi excitation and subsequent coupling to the 1pi sigma* potential energy surface via a conical intersection between the respective surfaces--thereby validating recent theoretical predictions regarding the importance of this process (Sobolewski et al., Phys. Chem. Chem. Phys., 2002, 4, 1093). Analysis provides an upper limit for the N-H bond strength in indole: D0(H-indolyl) < or = 31,900 cm(-1). Unimolecular decay of highly vibrationally excited ground state molecules formed by internal conversion from the initially prepared 1pi pi* states is a source of (slow) H atoms but their contribution to the TKER spectra measured in the present work is dwarfed by that from H atoms generated by one or more (unintended but unavoidable) multiphoton processes.

The role of pisigma* excited states in the photodissociation of heteroaromatic molecules.

High-resolution measurements of the kinetic energies of hydrogen atom fragments formed during ultraviolet photolysis of imidazole, pyrrole, and phenol in the gas phase confirm that N(O)-H bond fission is an important nonradiative decay process from their respective 1pisigma* excited states. The measurements also reveal that the respective cofragments (imidazolyl, pyrrolyl, and phenoxyl) are formed in very limited subsets of their available vibrational states. Identification of these product states yields uniquely detailed insights into the vibronic couplings involved in the photoinduced evolution from parent molecule to ultimate fragments.

Angiolymphoid hyperplasia with eosinophilia in association with a vascular malformation.

A unique case is presented in which a lesion of angiolymphoid hyperplasia occurs in association with a vascular malformation. The skin and the intravascular lesion showed, on microscopic examination, angiolymphoid hyperplasia, which to my understanding, is a reactive process. The nodule represents, in my view, satellite lesions of the A-V malformation--in other words a skin manifestation of the intravascular process. The same phenomenon has been reported in some pyogenic granulomas and hemangiomas.