8-bit or 11-bit monochrome displays—which image is preferred by the radiologist?

Objectives  

Vendors of medical displays promise a better diagnostic performance using 10- or 11-bit instead of 8-bit monochrome displays. We measured the gain of “Just Noticeable Difference” (JND) steps using high grayscale resolutions and evaluated the preference of radiologists regarding different aspects of image quality.     

Do medical examiners determine elder mistreatment as a cause of death?

This study examines the decision-making process of medical examiners in determining elder mistreatment in cases that present to the county morgue. Harris County Medical Examiners were surveyed about factors that influence the determination whether elder abuse or neglect was a contributor to the cause of death. At the time of the survey, all 11 Harris County Medical Examiners participated. Of these, 8 did not determine elder abuse or neglect as contributing to the cause of death in the 12 months prior to the survey, 6 reported that medical records were helpful “all the time”, 3 reported “most of the time”, and 2, indicated that the records were “some-times helpful”. The survey also indicated that information that assists medical examiners in identifying the potential for abuse or neglect ranged from “present most of the time” to “never present”. Multiple factors including autopsy findings, medical compliance, inconsistency in injury findings, and malnutrition were reported as helpful in determining elder abuse or neglect. Further studies are needed to determine additional factors that would provide medical examiners with the ability to more readily identify signs of elder abuse or neglect.     

Attenuation correction in cardiac SPECT: The boy who cried wolf?

Conclusion  We would like to stress that we do not necessarily consider AC for SPECT MPI to be unfeasible or unworthy of scientific pursuit; indeed, a great deal of creative scientific effort has been poured into this area of investigation over the past 3 decades, and much of it has contributed to a better understanding of the physics, as well as the clinical aspects, of our field. However, the great variety of available AC hardware and software “flavors,” the historical pattern of commercial release of insufficiently validated AC implementations, and the increasingly clouded health care reimbursement horizon may have created an environment where the envisioned users of the technology have been desensitized and discouraged from expecting it to ever come to fruition in a standardized, validated, and costeffective form. It has been reported as recently as 2005 that the “entire base of SPECT cameras has only 5% of systems with attenuation correction.”8 Perhaps the reports of AC’s demise are exaggerated, but it certainly seems as if the people have spoken and, after readying themselves for the wolf one too many times, have come to the conclusion that “the future (of AC) ain’t what it used to be” . . .at least not yet.     

Imaging features suggestive of a conjoined nerve root on routine axial MRI

Objective The purpose of our study is to evaluate imaging features suggestive of a conjoined nerve root on routine axial MRI. Methods Two radiologists and two surgeons retrospectively reviewed the MRI of three cases in which a conjoined nerve root was discovered during operation and found three suggestive signs on routine axial MR images: “corner” (asymmetric morphology of the anterolateral corner of the dural sac), “fat crescent” (intervening extradural fat between the asymmetric dura and the nerve root), and “parallel” signs (visualization of the entire parallel course of the nerve root at the disc level). Two radiologists prospectively found these signs during routine MRI interpretation sessions over a period of 6 months. If one or a combination of signs were noted on axial MR images, contiguous axial scans were additionally obtained. Three cases that were previously found during operations were also included. Prevalence and confidence scores for each sign were assessed on axial T1- and T2-weighted images. Results Twelve patients showed one or a combination of the three signs, 9 had contiguous axial MR scans. Five cases were confirmed by operation. The prevalence of the corner, fat crescent, and parallel signs were 12 out of 12 (100%), 6 out of 12 (50%), and 8 out of 12 (67.7%) on axial T1-weighted images. The overall diagnostic confidence was higher on T1- than on T2-weighted images (P < 0.05). Conclusion On routine axial L-spine MRI, corner, fat crescent, and parallel signs are suggestive of and assist in the recognition of a conjoined nerve root.     

Comparative reject analysis in conventional film-screen and digital storage phosphor radiography

The aim of this study was comparative analysis of rejected radiographs in conventional and digital radiology under the aspects number of rejected images and reasons for rejection. During 2 months waste films of conventional radiography were collected; in digital radiography each image-delete command at the postprocessing workstation was documented. Rejected images were analysed and assigned to four categories. The overall reject rate was 27.6 % in the conventional and 2.3 % in the digital department. Whereas in the conventional department the main reason for rejection was “exposure” and “others” (i. e. problems related to film handling), the main reason in the digital environment was “positioning”. The high exposure tolerance of digital systems markedly reduces the amount of faulty images. This is not only economically rewarding, but may also reduce unnecessary X-ray exposure of patients due to image retake. Received: 9 September 1998; Revision received: 23 November 1998; Accepted: 7 January 1999     

International use of an academic nephrology World Wide Web site: from medical information resource to business tool

BACKGROUND: Studies of the use of the World Wide Web to obtain medical knowledge have largely focused on patients. In particular, neither the international use of academic nephrology World Wide Web sites (websites) as primary information sources nor the use of search engines (and search strategies) to obtain medical information have been described. METHODS: Visits ("hits") to the Walter Reed Army Medical Center (WRAMC) Nephrology Service website from April 30, 2000, to March 14, 2001, were analyzed for the location of originating source using Webtrends, and search engines (Google, Lycos, etc.) were analyzed manually for search strategies used. RESULTS: From April 30, 2000 to March 14, 2001, the WRAMC Nephrology Service website received 1,007,103 hits and 12,175 visits. These visits were from 33 different countries, and the most frequent regions were Western Europe, Asia, Australia, the Middle East, Pacific Islands, and South America. The most frequent organization using the site was the military Internet system, followed by America Online and automated search programs of online search engines, most commonly Google. The online lecture series was the most frequently visited section of the website. Search strategies used in search engines were extremely technical. CONCLUSIONS: The use of "robots" by standard Internet search engines to locate websites, which may be blocked by mandatory registration, has allowed users worldwide to access the WRAMC Nephrology Service website to answer very technical questions. This suggests that it is being used as an alternative to other primary sources of medical information and that the use of mandatory registration may hinder users from finding valuable sites. With current Internet technology, even a single service can become a worldwide information resource without sacrificing its primary customers.     

Late Effects of Thoracic Irradiation in Children

Purpose:  To summarize the literature regarding the late effects of radiotherapy to the thorax in childhood and adolescence with special emphasis on cardiac and pulmonary impairment. Material and Methods:  The literature was critically reviewed using the PubMed^? database with the key words “late effects”, “late sequelae”, “child”, “childhood”, “adolescence”, “radiation”, “radiotherapy”, “thorax”, “lung”, “heart”, and “pulmonary”. Results:  17 publications dealing with radiation-induced pulmonary and cardiac late sequelae in children could be identified and were analyzed in detail. 29 further publications with additional information were also included in the analysis. Pulmonary function impairment after mediastinal irradiation arose in one third of all pediatric patients, even when treatment was performed with normofractionated lower doses (15–25 Gy). Whole lung irradiation was regularly followed by pulmonary function impairment with differing rates in several reports. However, clinically symptomatic function impairment like dyspnea was less frequent. Irradiation of up to 25 Gy (single doses ≤ 2 Gy) to the heart showed little or no cardiac toxicity in analyses of irradiated children (median follow-up 1.3–14.3 years). Doses of > 25 Gy (single doses ≤ 2–3.3 Gy) led to several cardiac dysfunctions. However, new data from adults with longer follow-up may indicate threshold doses as low as 1 Gy. Impairment of skeletal growth, breast hypoplasia, and secondary malignancy were further potential late sequelae. Conclusion:  Several retrospective reports described radiation-associated late sequelae in children. However, there is still a lack of sufficient data regarding the characterization of dose-volume effects.      

MRI of small bowel Crohn’s disease: determining the reproducibility of bowel wall gadolinium enhancement measurements

This study aims to determine inter- and intra-observer variation in MRI measurements of relative bowel wall signal intensity (SI) in Crohn’s disease. Twenty-one small bowel MRI examinations (11 male, mean age 40), including T1-weighted acquisitions acquired 30 to 120s post-gadolinium, were analysed. Maximal bowel wall SI (most avid, conspicuous contrast enhancement) in designated diseased segments was measured by two radiologists and two trainees using self-positioned “free” regions of interest (ROIs) followed by “fixed” ROIs chosen by one radiologist, and this procedure was repeated 1 month later. Relative enhancement (post-contrast SI minus pre-contrast SI/pre-contrast SI) was calculated. Data were analysed using Bland–Altman limits of agreement and intra-class correlation. Inter-observer agreement for relative enhancement was poor (spanning over 120%) using a free ROI—95% limits of agreement −0.69, 0.70 and −0.47, 0.74 for radiologists and trainees, respectively, only marginally improved by use of a fixed ROI −0.60, 0.67 and −0.59, 0.49. Intra-class correlation ranged from 0.46 to 0.72. Intra-observer agreement was slightly better and optimised using a fixed ROI—95% limits of agreement −0.52, 0.50 and −0.34, 0.28 for radiologists and trainees, respectively. Intra-class correlation ranged from 0.49 to 0.86. Relative bowel wall signal intensity measurements demonstrate wide limits of observer agreement, unrelated to reader experience but improved using fixed ROIs.     

Scratched pustule or gunshot wound? A medical odyssey

The diagnosis of a gunshot wound can be difficult especially if the morphology is not typical. In the case presented a neck injury was not recognised as a gunshot wound by several clinicians and radiologists although the bullet could be seen at the base of the patient’s tongue and on all X-rays taken. This misinterpretation may have been caused by a “professional blinkers phenomenon”. Received: 20 September 2000 / Accepted: 24 September 2000     

Skull base: pseudolesion or true lesion?

The skull base is a complex anatomical structure. Therefore, radiologists often use “side-to-side” comparison for detection of abnormalities. This approach is compromised by the high frequency of anatomical variations involving the skull base and the common presence of flow-related artifacts within vessels at the skull base that might mimic true lesions. The spectrum of “pseudolesions” ranging from different anatomical variations, such as unusual arachnoid granulations, asymmetric pneumatization and/or appearance of neurovascular foramina, to flow-related artifacts will be discussed in this review article, and tips for their distinction from a true lesion in a similar location will be given.     

Cyclops and cyclopoid formation after anterior cruciate ligament reconstruction: clinical and histomorphological differences

Prospectively, 119 patients were pursued clinically and by follow-up-arthroscopy for the occurrence of a “cyclops syndrome” after ACL reconstruction with a patellar tendon autograft, augmented by LAD. Twenty-one patients showed nodular formations. Ten of these (group 1) developed early clinical evidence of a “cyclops syndrome” with a mean extension deficit of 19° before follow-up-arthroscopy, on average 5.9 months after the index operation. The nodular formations found and excised during débridement had a hard consistency. Histomorphological undecalcified microtome section evaluation of six specimens revealed fibrocartilagineous tissue with active bone formation in the center. The other 11 patients showed no clinical symptoms (group 2). A similar but soft nodulous scar formation was detected at follow-up-arthroscopy, on average 9.5 months after the index operation. Histomorphologically these so-called “cyclopoid” formations were only built-up fibrocartilagineous islands surrounded by granulation tissue. Neither remnants of tendon graft fibers nor old bone particles were found in specimens of either group. It can be concluded that both the hard cyclops and the soft “cyclopoid” are de novo scar formations. Received: 4 November 1998 Accepted: 5 May 1999     

High resolution computed tomography of the chest in cystic fibrosis (CF): is simplification of scoring systems feasible?

The purpose of this study was to simplify HRCT scoring systems (SS) for CF by selecting representative HRCT parameters. Forty-two consecutive patients with CF underwent baseline and follow-up chest HRCT. Three radiologists evaluated 84 HRCTs employing five SS. “Simplified” HRCT SS were formed by selection of parameters exhibiting statistically significant relations with FEV1. Pulmonary function tests (PFTs) and nutrition (IBW%) were recorded. Regression analysis, Pearson correlation and T-test were used for statistical analysis. Three HRCT parameters were selected for the formation of “simplified” HRCT SS (severity of bronchiectasis, bronchial wall thickening, atelectasis-consolidation) using regression analysis. There was excellent correlation between each “simplified” and corresponding complete score (0.892 < r < 0.0967, p < 0.0001) or the remaining four complete scores (0.786 < r < 0.961, p < 0.0001). Strong correlation was found among the five “simplified” scores (0.803 < r < 0.997, p < 0.0001). Comparing baseline complete and “simplified” scores with corresponding follow-up ones, significant worsening was observed (p < 0.0001). PFTs and IBW% did not change significantly. HRCT scores correlated moderately with FVC and FEV1, but there was no correlation with FEF25-75 and IBW%. “Simplified” HRCT SS are as reliable as the complete ones and detect progression of lung disease earlier than clinical parameters. They are easy to use and could be adopted in clinical practice.     

Basic knowledge of Internet in forensic medicine: logging on, fetching files and information

The Internet stands at the forefront of telecommunications in medicine, including forensic medicine, since information technology (IT) has been able to revolutionize medical and scientific practices. Today, forensic physicians and professionals need to be familiar with the use of computers and the key applications of information technology: multimedia and the Internet. From the office, the forensic physician can communicate with other physicians by means of e-mail, take part in discussion groups, obtain information on meetings and get information from public libraries and various databases by means of file transfer protocol. The search among the huge amount of information is facilitated by the 'click and play' use of the Internet, by its increased ease and availability of access and by faster communications to an increasing number of accessible technical, scientific and biomedical resources. Therefore, it is useful to introduce some of the most frequent concepts encountered when exploring the Internet, to give simple references for any forensic physician exploring the Internet and to present typical Internet aspects by illustrations saved from worldwide websites and linked to the accompanying text. Some of the main forensic websites and basic Internet procedures are described, explaining how to search and exchange information in the domain of forensic medicine and sciences. Search engines and search procedures on the worldwide web are briefly explained. The aim of this paper is to give forensic physicians, scientists and law professionals some basic tools and references to access the vast possibilities of the Internet.     

Anterior subluxation of the cervical spine

Anterior subluxation (AS), or hyperflexion sprain, generates a disproportionate level of concern in emergency medicine. Anxiety related to this injury arises from the fact that AS may produce delayed mechanical instability of the cervical spine, with resultant pain and neurological impairment. Furthermore, its radiographic presentation may be very subtle, and it may be impossible to reliably diagnose or exclude this injury using standard screening radiographs. Additional studies, such as flexion–extension (FE) radiography and magnetic resonance (MR) imaging, are often used in the acute setting to assess injury status and radiographically exclude AS injury. There are a number of reasons to discourage this latter practice, which can represent an impossible attempt to “radiographically clear the cervical spine” of blunt trauma patients with “100 % certainty.” This is because AS is an uncommon lesion, and the neurological deficits secondary to delayed instability are almost always minor and transient. Furthermore, AS is usually not entirely occult on screening plain films (which are typically “abnormal” even if in nonspecific ways). Finally, FE imaging, done acutely in the presence of spasm, is probably unable to exclude this diagnosis reliably, even when plain films are normal, and emergent MR, probably the most accurate technique, is not widely available. Risk stratification provides a rational alternative approach for assessing injury status. Low-risk patients may be spared further imaging provided they are given appropriate precautionary return instructions. High-risk patients require emergent evaluation by an experienced spine specialist, and may benefit from advanced imaging. Patients at moderate risk may be best managed with symptomatic treatment, warnings to avoid significant physical activity, and delayed FE imaging and evaluation by a spinal specialist. They should also be instructed to seek immediate medical attention if they develop any indications of delayed instability, including severe pain and /or neurological signs. This stratified approach not only increases the likelihood that delayed subluxation will be recognized before it leads to chronic instability, but frees clinicians and radiologists from the quixotic burden of trying to “clear” the cervical spine with 100 % certainty in the acute setting.     

Endovaginal color Doppler sonographic evaluation of ectopic pregnancy in women after in vitro fertilization and embryo transfer

The aim of this study was to evaluate the value of endovaginal color Doppler ultrasonography in the early diagnosis of ectopic pregnancy in women after in vitro fertilization and embryo transfer, and to correlate the sonographic findings with ?-hCG serum levels. Thirty-five patients had proven ectopic pregnancies and 4 other patients had heterotopic pregnancies. The diagnosis was disclosed correctly in all cases by endovaginal color Doppler US by identifying an adnexal mass with placental flow and a nongravid uterus called a “cold uterus”. An intrauterine sac with “double ring sign” was found in all normal intrauterine pregnancies when the hCG levels exceeded 1000 IU/l but in none of the patients with ectopic pregnancy (EP). These findings suggest the efficacy of the discriminatory hCG serum level of 1000 IU/l in the investigation of EP. In conclusion, this study describes the diagnostic importance of transvaginal color Doppler US in correlation with hCG serum levels in the early detection of EP avoiding life-threatening complications and improving patient outcome. Received: 4 May 1998; Revision received: 10 August 1998; Accepted: 10 September 1998     

Revisit image control for pediatric chest radiography

Purpose The aim of this study was to analyze the fraction defectiveness and efficacy of the patient immobilization device (PID) for pediatric chest radiography. Materials and methods We examined 840 plain chest radiographs in six hospitals, including four children's hospitals and two general hospitals. The mean age of the patients was 1.9 years (range 0–5 years). Two board-qualified pediatric radiologists rated (into three grades, by consensus) the degree of inspiration, rotation, lordosis, scoliosis, and cutoff or coning as well as the quality of the chest radiographs. Results The incidence of “poor” and “very poor” quality examinations was 2/140 and 3/140 in each of two children's hospitals using PID. The corresponding figures were 9/139 and 17/140 in the two children's hospitals that did not use PID. The general hospital using PID had 14/140 “poor” and “very poor” examinations. The general hospital that did not use PID had 28/140 “poor” and “very poor” examinations. Thus, statistically better quality chest radiography was obtained with the use of PID (P < 0.001). Likewise, rotation, lordosis, and scoliosis were less frequently diagnosed as present when PID was used (P < 0.001, 0.001, 0.05). Cutoff or coning had no relation to the use of PID (P = 0.13). No significant difference was found between the degree of inspiration and the use of PID (P = 0.56). Conclusion Fraction defectiveness in the general hospital that did not use PID was as much as 14 times higher than that of the children's hospitals that used PID. The patient immobilization device is recommended for hospitals with technologists not specifically trained for pediatric examination.     

The “Pocket shot”: Complications of intravenous drug abuse

Intravenous drug users frequently resort to supraclavicular injection for central venous access. Few reports of complications associated with the “pocket shot” have appeared in the radiologic literature. This paper defines the anatomy of the “pocket” and presents the radiographic manifestations of complications associated with this practice.     

Spiral CT of pulmonary nodules: interobserver variation in assessment of lesion size

The aim of this study was to assess interobserver variability in size determination of pulmonary nodules at spiral CT. Twenty-three patients with known pulmonary nodules (diameter 2–40 mm, mean diameter 7 mm) underwent spiral chest CT (collimation 5 mm, pitch 1). Images were reconstructed at 3- and 5-mm intervals (RI). Hard copies were analyzed by two radiologists who recorded every nodule with regard to location, diagnostic confidence (“definite,”“probable”) and nodule size in increments of 1 mm with specific attention to correct classification into one of three size classes (≤ 5 mm, 6–10 mm, > 10 mm). Interobserver variability was determined with Pearson's correlation coefficient and k measure. Of a total of 286 nodules, 103 nodules were found accordingly by both readers at 3 mm RI, and 96 at 5 mm RI. There was a good correlation of measurements (in millimeters) between both readers (Pearson's correlation coefficient: 0.89–0.95). Interobserver variability in categories was good at both reconstruction intervals (k: 0.61 at 3 mm, 0.74 at 5 mm RI) and very good (0.81) at 5 mm RI when uncertain nodules were excluded. Spiral CT allows reproducible size determination of pulmonary nodules as shown by good interobserver agreement in exact size measurement and categorization into three size classes. Received: 2 September 1999; Revised: 24 January 2000; Accepted: 27 January 2000     

MRI demonstration of subarachnoid neurocysticercosis simulating metastatic disease

We present a patient with neurocysticercosis with spinal subarachnoid spread who presented with lower back pain and progressive numbness and weakness of the left leg. MRI of the spine simulated metastasis. MRI of the brain demonstrated a “bunch of grapes” appearance in the basal cisterns, characteristic of cysticercosis. Received: 2 March 1998 Accepted: 7 March 1998