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Primary infarction of the greater omentum is a rare cause of acute abdominal syndrome. Rate of occurrence may nevertheless be underestimated. We report a series of six cases observed over a 30-month period with US and CT imaging. We assessed early signs and their course. CT-scans depicted fatty oval-shaped masses below the right anterior or anterolateral parietal wall, associated with a thickening of the anterior parietal peritoneum, explaining symptom pathogenesis. Torsion can be identified, but has no specific impact on prognosis. Follow-up CT scan may evidence spontaneous, but sometimes slow, resolution.
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The purpose of this study was to review economic considerations related to establishing a diagnosis of Crohn's disease, and to compare the costs of a diagnostic algorithm incorporating wireless capsule endoscopy (WCE) with the current algorithm for diagnosing Crohn's disease suspected in the small bowel. Published literature, clinical trial data on WCE in comparison to other diagnostic tools, and input from clinical experts were used as data sources for (1) identifying contributors to the costs of diagnosing Crohn's disease; (2) exploring where WCE should be placed within the diagnostic algorithm for Crohn's; and (3) constructing decision tree models with sensitivity analyses to explore costs (from a payor perspective) of diagnosing Crohn's disease using WCE compared to other diagnostic methods. Literature review confirms that Crohn's disease is a significant and growing public health concern from clinical, humanistic and economic perspectives, and results in a long-term burden for patients, their families, providers, insurers, and employers. Common diagnostic procedures include radiologic studies such as small bowel follow through (SBFT), enteroclysis, CT scans, ultrasounds, and MRIs, as well as serologic testing, and various forms of endoscopy. Diagnostic costs for Crohn's disease can be considerable, especially given the cycle of repeat testing due to the low diagnostic yield of certain procedures and the inability of current diagnostic procedures to image the entire small bowel. WCE has a higher average diagnostic yield than comparative procedures due to imaging clarity and the ability to visualize the entire small bowel. Literature review found the average diagnostic yield of SBFT and colonoscopy for work-up of Crohn's disease to be 53.87%, whereas WCE had a diagnostic yield of 69.59%. A simple decision tree model comparing two arms--colonoscopy and SBFT, or WCE--estimates that WCE produces a cost savings of 291dollars for each case presenting for diagnostic work-up for Crohn's. Sensitivity analysis varying diagnostic yields of colonoscopy and SBFT vs. WCE demonstrates that WCE is still less costly than SBFT and colonoscopy even at their highest reported yields, as long as the diagnostic yield of WCE is 64.10% or better. Employing WCE as a first-line diagnostic procedure appears to be less costly, from a payor perspective, than current common procedures for diagnosing suspected Crohn's disease in the small bowel. Although not addressed in this model, earlier diagnosis with WCE (due to higher diagnostic yield) also could lead to earlier management, improved quality of life and workplace productivity for people with Crohn's disease.
BACKGROUND: Diagnostic error is a significant problem in specialities characterised by diagnostic uncertainty such as primary care, emergency medicine and paediatrics. Despite wide-spread availability, computerised aids have not been shown to significantly improve diagnostic decision-making in a real world environment, mainly due to the need for prolonged system consultation. In this study performed in the clinical environment, we used a Web-based diagnostic reminder system that provided rapid advice with free text data entry to examine its impact on clinicians' decisions in an acute paediatric setting during assessments characterised by diagnostic uncertainty. METHODS: Junior doctors working over a 5-month period at four paediatric ambulatory units consulted the Web-based diagnostic aid when they felt the need for diagnostic assistance. Subjects recorded their clinical decisions for patients (differential diagnosis, test-ordering and treatment) before and after system consultation. An expert panel of four paediatric consultants independently suggested clinically significant decisions indicating an appropriate and 'safe' assessment. The primary outcome measure was change in the proportion of 'unsafe' workups by subjects during patient assessment. A more sensitive evaluation of impact was performed using specific validated quality scores. Adverse effects of consultation on decision-making, as well as the additional time spent on system use were examined. RESULTS: Subjects attempted to access the diagnostic aid on 595 occasions during the study period (8.6% of all medical assessments); subjects examined diagnostic advice only in 177 episodes (30%). Senior House Officers at hospitals with greater number of available computer workstations in the clinical area were most likely to consult the system, especially out of working hours. Diagnostic workups construed as 'unsafe' occurred in 47/104 cases (45.2%); this reduced to 32.7% following system consultation (McNemar test, p < 0.001). Subjects' mean 'unsafe' workups per case decreased from 0.49 to 0.32 (p < 0.001). System advice prompted the clinician to consider the 'correct' diagnosis (established at discharge) during initial assessment in 3/104 patients. Median usage time was 1 min 38 sec (IQR 50 sec-3 min 21 sec). Despite a modest increase in the number of diagnostic possibilities entertained by the clinician, no adverse effects were demonstrable on patient management following system use. Numerous technical barriers prevented subjects from accessing the diagnostic aid in the majority of eligible patients in whom they sought diagnostic assistance. CONCLUSION: We have shown that junior doctors used a Web-based diagnostic reminder system during acute paediatric assessments to significantly improve the quality of their diagnostic workup and reduce diagnostic omission errors. These benefits were achieved without any adverse effects on patient management following a quick consultation.
Structured diagnostic interviews, which evolved along the development of classification's systems, are now widely used in adult psychiatry, in the fields of clinical trials, epidemiological studies, academic research as well as, more recently, clinical practice. These instruments improved the reliability of the data collection and interrater reliability allowing greater homogenisation of the subjects taking part in clinical research, essential factor to ensure the reproducibility of the results. The diagnostic instruments, conversely to the clinical traditional diagnostic processes allow a systematic and exhaustive exploration of disorders, diagnostic criteria but also severity levels, and duration. The format of the data collection, including the order of exploration of the symptoms, is fixed. The formulation of the questions is tested to be univocal, in order to avoid confusions. In child and adolescent, researches in pharmacology and epidemiology increased a lot in the last decade and the standardisation of diagnostic procedures is becoming a key feature. This Article aims to make an assessment, a selection, and a description of the standardized instruments helping psychiatric diagnosis currently available in the field of child and adolescent's psychiatry. Medline and PsycINFO databases were exhaustively checked and the selection of the instruments was based on the review of four main criteria: i) compatibility with international diagnostic systems (DSM IV and/or ICD-10); ii) number of disorders explored; iii) peer reviewed Journals and iv) richness of psychometric data. After the analysis of the instruments described or mentioned in the literature, 2 structured interviews [the Diagnostic Interview Schedule for Children (DISC) and the Children's Interview for Psychiatric Syndromes (ChIPS)] and 4 diagnostic semi-structured interviews [the Schedule for Affective Disorders and Schizophrenia for School-Age Children (Kiddie-SADS), the Diagnostic Interview for Children and Adolescent (DICA), the Child and Adolescent Psychiatric Assessment (CAPA) and the Interview Schedule for Children and Adolescents ISCA)] were retained according to the 3 first criteria. All can be administered by clinicians, and x out of 6 can also be administered by lay-interviewers. All include a child/adolescent version and a parent version. Two instruments evaluate the presence of DSM IV axe II disorders: The ISCA explores the criteria of the Antisocial Personality Disorder. The CAPA evaluates Borderline, Obsessional-compulsive, Histrionic and Schizotypic Personality Disorders. Regarding the psychometric quality criterion, the selection was much more difficult because of the lack of data and the weakness of the samples studied in reliability studies. Interrater reliability appeared to be good for the 6 instruments, with kappas ranging from 0.5 to 1. This is usual in such instruments. The test-retest reliability was found to vary from bad to excellent depending on the instruments, the "informant" status (child/adolescent or parent), and the disorder explored, kappas ranging from 0.32 to 1. The worst results concerned face-to-face reliability studies which showed weak concordances for the diagnoses, whatever the procedure implemented: Diagnostic interview vs. i) Another diagnostic interview, vs. ii) An expert diagnosis or vs. iii) Scales and questionnaires. Overall, the K-SADS-PL appeared to be the instrument that has the best test-retest reliability for Anxious Disorders and Affective Disorders (the value kappa showing good to excellent reliabilities). Several important methodological observations emerged from this review. Firstly, the metrological data corresponding to the diagnoses according to DSM IV or ICD-10 criteria's were lacking. The face validity was globally satisfactory, but the data concerning their face-to-face validities and their test-retest reliability, although better than in the former versions, were limited because they were tested on small sample. In fact, it appeared that the agreements depend on the informant, the sample studied, the various diagnostic categories and the instrument used. Since the studies carried out by Cohen et al., with now obsolete versions of the DISC and K-SADS, no other study establishing a comparison between two EDS have been conducted. Consequently, the clinicians must be very careful before comparing DSM or ICD diagnoses generated by different instruments. The second point was the length of the interviews that appeared sometimes longer than instruments used in adults, considering the fact that diagnostic procedure implies two independent interviews, one with the child/adolescent and one with the adult referent. The minimum duration was found to be 1 h 30 for the Chips in clinical setting, while it could reach 4 h or more for the DISC IV or the ISCA. The interviews had to be often carried out in several sessions, so the assessment became very difficult in easily tired and/or distractible subjects. The third point referred to the necessity to consider multiple data sources in young patients during the diagnostic procedure, and the weakness of the levels of agreement generally reported between sources. Empirically, it was observed that the investigator granted more weight to the report of the children than to the parent's one, when the clinical judgement was necessary to synthesize the data. On another level, studies showed a high agreement on the factual contents or on the specific events (ex: hospitalization), like on the obvious symptoms (ex: enuresis). The parents report more problems of behaviour, school and relational difficulties, whereas the children report more fear, anxiety, obsessions and compulsions, or delusional ideas. In other words, it appeared that children were better informants in describing their mental states (internalised disorders), and that adults would bring more reliable information in describing externalised disorders. Like McClellan and Werry, we think that further researches are needed to clarify if and when this is the case. The last major point concerned the problem of language. These instruments must be used in the maternal language of the interviewees and they were developed for most of them into English only. For example, there is only one instrument available into French (the Kiddie SADS). Nowadays, it remains difficult to conduct international studies in child and adolescent psychiatry and/or to compare data is this domain. To conclude, the use of the EDS and EDSS brings many benefits, in academic researches as well as in clinical practice, but a more systematic use is limited by a certain number of parameters. The instruments currently available in child and adolescent are far from being optimal in terms of quality and quantity. It seems necessary and useful to contribute to their development and their improvement. In particular, the following points should be considered: drastic reduction of the length of the interviews; simplification in the use of these instruments, during the interviews, but also in the treatment of the data collected during the final phase of diagnosis generation, the clinician having to carry out ceaseless returns to check the presence or not of each diagnostic criterion; reduction of the duration of the highly necessary training, which can be easily solved by the global simplification of the instruments; quantitative and qualitative improvements of psychometric properties, in particular in terms of sensitivity, specificity and face-to-face validity. Finally, it is highly necessary to continue to develop structured diagnostic interviews adapted to the assessment of child and adolescent psychiatric diagnoses keeping in mind simplicity, feasibility and reliability. Developing this kind of instruments is hard, expensive, and sometimes tiresome but it remains the inescapable stage to produce high quality data in the future.
BACKGROUND: Prader-Willi syndrome (PWS) is a complex, multisystem disorder. Its major clinical features include neonatal hypotonia, developmental delay, short stature, behavioral abnormalities, childhood-onset obesity, hypothalamic hypogonadism, and characteristic appearance. The genetic basis of PWS is also complex. It is caused by absence of expression of the paternally active genes in the PWS critical region on 15q11-q13. In approximately 70% of cases this is the result of deletion of this region from the paternal chromosome 15. In approximately 28%, it is attributable to maternal uniparental disomy (UPD; inheritance of 2 copies of a chromosome from the mother and no copies from the father, as opposed to the normal 1 copy from each parent) of chromosome 15, and in <2%, it is the result of a mutation, deletion, or other defect in the imprinting center. Clinical diagnostic criteria were established by consensus in 1993. Subsequently, definitive molecular genetic testing became available for laboratory diagnosis of PWS. However, identification of appropriate patients for testing remains a challenge for most practitioners because many features of the disorder are nonspecific and others can be subtle or evolve over time. For example, hypotonic infants who are still in the failure to thrive phase of the disorder often do not have sufficient features for recognition of PWS and often are not tested. Initial screening with these diagnostic criteria can increase the yield of molecular testing for older children and adults with nonspecific obesity and mental retardation. Therefore, the purpose of clinical diagnostic criteria has shifted from assisting in making the definitive diagnosis to raising diagnostic suspicion, thereby prompting testing. We conducted a retrospective review of patients with PWS confirmed with genetic testing to assess the validity and sensitivity of clinical diagnostic criteria published before the widespread availability of testing for all affected patients and recommend revised clinical criteria. METHODS: Charts of all 90 patients with laboratory-confirmed PWS were reviewed. For each patient, the presence or absence of the major, minor, and supportive features listed in the published diagnostic criteria was recorded. The sensitivity of each criterion, mean of the total number of major and minor criteria, and mean total score for each patient were calculated. RESULTS: There were 68 patients with a deletion (del 15q11-q13), 21 with maternal UPD of chromosome 15, and 1 with a presumed imprinting defect. Age range at the time of the most recent evaluation was 5 months to 60 years (median: 14.5 years; del median: 14 years; range: 5 months-60 years; UPD median: 18 years; range: 5-42 years). The sensitivities of the major criteria ranged from 49% (characteristic facial features) to 98% (developmental delay). Global developmental delay and neonatal hypotonia were the 2 most consistently positive major criteria and were positive in >97% of the patients. Feeding problems in infancy, excessive weight gain after 1 year, hypogonadism, and hyperphagia were all present in 93% or more of patients. Sensitivities of the minor criteria ranged form 37% (sleep disturbance and apneas) to 93% (speech and articulation defects). Interestingly, the sensitivities of 8 of the minor criteria were higher than the sensitivity of characteristic facial features, which is a major criterion. Fifteen out of 90 patients with molecular diagnosis did not meet the clinical diagnostic criteria retrospectively. CONCLUSION: When definitive diagnostic testing is not available, as was the case for PWS when the 1993 criteria were developed, diagnostic criteria are important to avoid overdiagnosis and to ensure that diagnostic test development is performed on appropriate samples. When diagnostic testing is available, as is now the case for PWS, diagnostic criteria should serve to raise diagnostic suspicion, ensure that all appropriate people are tested, and avoid the expense of testing unnecessarily. Our results indicate that the sensitivities of most of the published criteria are acceptable. However, 16.7% of patients with molecular diagnosis did not meet the 1993 clinical diagnostic criteria retrospectively, suggesting that the published criteria may be too exclusive. A less strict scoring system may ensure that all appropriate people are tested. Accordingly, we suggest revised clinical criteria to help identify the appropriate patients for DNA testing for PWS. The suggested age groupings are based on characteristic phases of the natural history of PWS. Some of the features (eg, neonatal hypotonia, feeding problems in infancy) serve to diagnose the syndrome in the first few years of life, whereas others (eg, excessive eating) are useful during early childhood. Similarly, hypogonadism is most useful during and after adolescence. Some of the features like neonatal hypotonia and infantile feeding problems are less likely to be missed, whereas others such as characteristic facial features and hypogonadism (especially in prepubertal females) may require more careful and/or expert examination. The issue of who should have diagnostic testing is distinct from the determination of features among confirmed patients. Based on the sensitivities of the published criteria and our experience, we suggest testing all newborns/infants with otherwise unexplained hypotonia with poor suck. For children between 2 and 6 years of age, we consider hypotonia with history of poor suck associated with global developmental delay sufficient criteria to prompt testing. Between 6 and 12 years of age, we suggest testing those with hypotonia (or history of hypotonia with poor suck), global developmental delay, and excessive eating with central obesity (if uncontrolled). At the ages of 13 years and above, we recommend testing patients with cognitive impairment, excessive eating with central obesity (if uncontrolled), and hypogonadotropic hypogonadism and/or typical behavior problems (including temper tantrums and obsessive-compulsive features). Thus, we propose a lower threshold to prompt diagnostic DNA testing, leading to a higher likelihood of diagnosis of this disorder in which anticipatory guidance and intervention can significantly influence outcome.
Announcement of schizophrenia diagnostic to the patients is a topical issue in France. The evolution in clinical practices, a better efficiency in therapeutic procedures and the fundamental right of the patient to obtain information have initialised the discussion of its interest. Spontaneous claim for information from the patient is rarely observed although awareness troubles might be reported at the instauration of the mental disorder or during its evolution. Methodological studies concerning the diagnostic announcement are limited. Except the Bayle studies recently published, only a few publications are available in France about the knowledge of their pathology and their need to be clearly informed. French scientific literature deals generally about medico-legal aspects of this information and consisted of survey about diagnostic announcement. International literature is more abundant and presents positive and negative aspects of the announcement. An information procedure of schizophrenia announcement to the patient has been developed in our hospitalisation unit of psychiatry. This procedure has taken place on the basis of the literature data, our specificity and our clinical experiences. For some Anglo-American psychiatrists who have proceeded to semi-structured interview in order to announce the diagnostic, information to the patients might improve the clinical relationship. Thus, compliance to the treatment is significantly increased. The ability of the patient to recognise the symptoms of the disease and to accept their consequences and the treatments is associated to a better social prognosis, daily activities and response to the treatment. The announcement impact justifies the prescription of neuroleptics, treatment that is notoriously perceived as prejudicial by the patients themselves or more commonly in the basic population. To obtain compliance to the treatment, a satisfactory acceptance of the mental disorder is required. Compliance is based on satisfactory information in order to gain the cooperation of the patient and its relative (10). Atkinson has classified four main types of arguments, the ethical principle to be informed, talk to explain and give sense to the symptoms, reduce the feeling of guilt perceived by the patient and his relative and enhance the collaboration between the patient and the nursing staff. According to Ferreri and Bayle studies French psychiatrists reluctance to announce schizophrenia diagnostic are the following: lack of request or of interrogations asked by the patient about their disease, diagnostic and prognosis uncertainty and irreversibility of the disease, complexity of the pathology and its origin which hinder an accessible explanation, cognitive disorders frequently observed with schizophrenic patients which may be associated with difficulties of understanding information, destabilization of the patient-nursing staff relationship and social stigmatisation risks. Other arguments like reluctance to give a "label" to the disease, too abstract diagnostic, a negative social vision and the possibility of discouragement for the relative are classically retrieved in French literature. In fact, divulgation of the term schizophrenia involves a panel of negative representations and is hindered by the confusion in the social imagination of such a term related with lost of control, quintessence of madness, dangerous behaviour possibilities, evil and incurability. Some psychiatrists do not transmit information arguing that significant obstruction of the future may be consecutive to the information. They prefer to use vague terms more socially acceptable like "nervous breakdown or depression, atypical or emotional disorder, dissociative troubles...". Information to the patient about his mental disorder is more frequent in psychiatry for affective, anxious and additive troubles than for schizophrenia. Our procedure of diagnostic announcement has been elaborated after preliminary discussion with the medical and nursing staff. Diagnostic of schizophrenia announcement has been presented by weighing the pros and cons according to the intemational literature. It clearly appeared that benefits for the patients prevail on the drawbacks. Nevertheless, inclusion and clinical supervision have to be carefully precised in particular to verify the ability to receive information. Short term objectives: deliver progressively information to the patient about his disease by means of an active and educational process with hope and optimism using a accessible language (explanation of each terms used with the intention of being well understood); quantify the impact of diagnostic announcement on the schizophrenic patient using clinical rating scales during a period of one month (clinical interview at day 1, day 7 and day 28). Mid term objectives: improve the global supervision and autonomy of schizophrenic by means of a therapeutic project helping the patient to become an active partner in the monitoring of his mental disorder; enhance a psycho-educational program after the procedure of announcement in order to optimise the observance of his treatment, increase his quality of life and answer to the requests of his relative; 45 patients (age 29.3 +/- 8.8 years old) have been included to be informed on their diagnostic since the elaboration of this procedure during a time period of 24 months. Time interval between the beginning of their pathology and the delivering of this information was 4.7 years. Most of them (56%) presented a paranoid type of schizophrenia. In most of the cases, the patients did not know their diagnostic or declared suffering from a diagnostic, which was erroneous; 80% of the 45 patients have complied with the procedure until its end. On more than 24 of following after the instauration of the diagnostic announcement procedure, these patients ha ve presented satisfactory observance to the medical supervision (medical consultation and drug intake); 60% of the patients were regularly present to their medical appointment. The number of patients included (45 patients) appears small compared to the time interval of the study (24 months) but was significant according to the great changes in our clinical approach. Thus, this procedure was not systematically applied, in particular the patients who did not want to be informed on their disease. Is it clinically relevant or not to announce diagnostic of schizophrenia to the patient? This issue remains questioned according to the few studies published at the present time, any consensus has been clearly presented on formal indications or contra-indications. If on an ethical side, this information appears logical, the medical and nursing staff should require special care. Special care must be taken before delivering information to the patients; each situation must be evaluated in order not to comply with an ideology of total and inadequate information, which could have serious consequences. Nevertheless, it appeared clearly that information must be given to stabilized patients with satisfactory insight. Moreover, psychotherapeutic projects become easier because patients awareness and understanding towards pathological symptoms are greatly improved. Partnership between patient and medical staff is the key of this dynamic and psycho-educative procedure, which opens new horizons in our therapeutic prospect.
BACKGROUND: Parallel to its technical development starting in the 1930s, electron microscopy (EM) became an important tool in basic and clinical virology. First utilized in the rapid diagnosis of smallpox, it developed to a diagnostic routine in the early 1960s using the negative staining technique. EM was applied to infected cell-cultures and also to 'dirty' specimens including urine, feces, vesicle fluid, liquor. With the implementation of molecular biological and genetic techniques, the use of diagnostic EM decreased. OBJECTIVES: (1) To give a perspective on future indications and possible uses by discussing the past and the present of diagnostic EM, (2) To describe the system of External Quality Assessment on EM virus diagnosis (EQA-EMV) established in 1994 by our laboratory and its achievements. STUDY DESIGN: EQA-EMV is run to evaluate, to confirm and to improve the quality of diagnostic EM. Two different types of specimen are sent out: (1) prepared grids to assess and train the diagnostic skills of the participants, (2) stabilized virus particle suspensions to assess preparation efficiency. RESULTS: Diagnostic EM differs from other diagnostic tests in its rapidity and its undirected 'open view'. To emphasize these advantages, the indications for diagnostic EM are discussed, fundamental for a continuing future adaptation. Besides appropriate techniques, quality control measures are required to achieve and keep high diagnostic standards. The results from 6 years of EQA-EMV are presented. CONCLUSIONS: In the history of diagnostic EM in virology, a change in use has been seen. Starting in the 1990s and coincident with the broad introduction of 'modern' diagnostic techniques, the number of EM diagnostic labs has decreased considerably--in spite of the obvious advantages of this technique. To guarantee the continuing performance of diagnostic EM in the future. EQA runs have to be performed as with other techniques in the diagnostic armament. The growing number of participants and participating countries indicates an interest in as well as a need for this program.
The aims of the present study were to develop diagnostic criteria of Internet addiction for adolescents and to examine the discriminating potential and validity of diagnostic criteria by an empirical community study among adolescent populations. We developed 13 candidate diagnostic criteria for characteristic symptoms of Internet addiction in adolescents. A total of 468 adolescents completed the Chen Internet Addiction Scale (CIAS) and were systematically assessed for Internet-using behaviors by seven psychiatrists using the diagnostic interview schedule. The sensitivity, specificity, and diagnostic accuracy of the 13 candidate diagnostic criteria were analyzed with references to the interviewers' global clinical impressions and CIAS results. The cutoff point of the diagnostic criteria to differentiate the Internet-addicted subjects with nonaddicted ones was then determined by the best diagnostic accuracy and the receiver operating characteristic curve. This study selected nine of the 13 candidate diagnostic criteria to construct the diagnostic criteria of Internet addiction for adolescents, which were composed of three main criteria: characteristic symptoms of Internet addiction, functional impairment secondary to Internet use, and exclusive criteria. The diagnostic criteria had high diagnostic accuracy, specificity, negative predictive value, accepted sensitivity, and accepted positive predictive rate. The validity of the diagnostic criteria proposed in this study was further confirmed by comparing the demographic and Internet-using characteristics between those with and without Internet addiction. The diagnostic criteria for Internet addiction can provide health care professionals with a means to communicate and make comparisons of clinical cases.
Considerable research has evaluated biological and psychological tests for various psychiatric disorders; however, few objective tests are included in DSM-IV as diagnostic criteria. It was recently suggested that existing tests are insufficiently accurate to be included as diagnostic criteria. While it is true that there are limitations in the sensitivity and/or specificity of such tests, this should not rule them out as effective diagnostic criteria. Studies examining the diagnostic efficiency of the DSM criteria sets demonstrate that the individual criteria vary in their sensitivity and specificity. In the present article, we suggest that the same standard should be applied to the evaluation of objective tests. That is, we suggest changing the perspective used to evaluate the performance of biological and psychological measures from the traditional one examining them as diagnostic tests to one in which these measures are evaluated as diagnostic criteria. To our knowledge, no previous investigators have compared the psychometric performance of an objective test to the psychometric performance of the DSM-IV symptom criteria. The recent report from the committee to develop a research agenda for the initial planning phase for DSM-V discussed the use of self-report symptom scales as possible diagnostic criteria in nonpsychiatric settings. In the present report from the Rhode Island Methods to Improve Diagnostic Assessment and Services project, we examined the performance of a self-report depression questionnaire as a diagnostic criterion for major depressive disorder (MDD). We compared the performance of the Diagnostic Inventory for Depression to the performance of the DSM-IV MDD symptom criteria in 1138 psychiatric outpatients. The results indicated that the diagnostic efficiency of the Diagnostic Inventory for Depression was similar to the loss of interest or pleasure criterion, and superior to all of the remaining DSM-IV MDD symptom criteria except low mood. We discuss issues related to the possible use of a self-administered depression symptom scale as a diagnostic criterion.
"Thyroid stunning" from diagnostic iodine-131 imaging prior to ablative therapy with (131)I for well-differentiated thyroid carcinoma has been well reported, but documentation of the effect on clinical outcome is sparse. The purpose of this retrospective study was to investigate the clinical effects of stunning. The outcome of (131)I ablative therapy in a group of patients ( n=36) who had diagnostic scans using 185 MBq (5 mCi) of (131)I was compared with that in a group ( n=36) who had diagnostic scans using 740 MBq (20 mCi) of (123)I. Patients were imaged at least 4 weeks after near-total thyroidectomy, prior to their first (131)I ablative therapy. Follow-up imaging was performed every 3-6 months, and further (131)I treatment administered when indicated. A group of patients ( n=36) who proceeded directly to their first therapy dose without a diagnostic scan and were followed up with (123)I was compared with the group who did have a (123)I diagnostic scan prior to the first ablative therapy. The efficacy of therapy was evaluated using ablation of the thyroid, evidenced by absence of uptake in the thyroid bed on the diagnostic scan, as the endpoint. Only 47% of patients in the (131)I diagnostic group had the thyroid gland ablated after a single administration of (131)I therapy, compared with 86% in the (123)I diagnostic group ( P<0.005). Patients who had (131)I diagnostic scans required higher total (131)I therapeutic activity (6.7 GBq or 180 mCi) to ablate the thyroid gland than those in the (123)I diagnostic group (4.4 GBq or 119 mCi). There was no difference in outcome between the group who did and the group who did not have a diagnostic study with (123)I prior to their first ablative therapy. The difference in outcome between the (131)I and the (123)I diagnostic groups demonstrates that the efficacy of (131)I therapy is reduced subsequent to the use of 185 MBq of (131)I for diagnostic imaging. This indicates that the phenomenon of stunning is clinically significant and affects the outcome of therapy.
There is behavioral evidence that different visual categorization tasks on various types of stimuli (e.g., faces) are sensitive to distinct visual characteristics of the same image, for example, spatial frequencies. However, it has been more difficult to address the question of how early in the processing stream this sensitivity to the information relevant to the categorization task emerges. The current study uses scalp event-related potentials recorded in humans to examine how and when information diagnostic to a particular task is processed during that task versus during a task for which it is not diagnostic. Subjects were shown diagnostic and anti-diagnostic face images for both expression and gender decisions (created using Gosselin and Schyns' Bubbles technique), and asked to perform both tasks on all stimuli. Behaviorally, there was a larger advantage of diagnostic over anti-diagnostic facial images when images designed to be diagnostic for a particular task were shown when performing that task, as compared to performing the other task. Most importantly, this interaction was seen in the amplitude of the occipito-temporal N170, a visual component reflecting a perceptual stage of processing associated with the categorization of faces. When participants performed the gender categorization task, the N170 amplitude was larger when they were presented with gender diagnostic images than with expression-diagnostic images, relative to their respective non-diagnostic stimuli. However, categorizing faces according to their facial expression was not significantly associated with a larger N170 when subjects categorized expression diagnostic cues relative to gender-diagnostic cues. These results show that the influence of higher-level task-oriented processing may take place at the level of visual categorization stages for faces, at least for processes relying on shared diagnostic features with facial identity judgments, such as gender cues.
BACKGROUND AND OBJECTIVE: Diagnosis of acute deep vein thrombosis (DVT) and of pulmonary embolism (PE) is often difficult: symptomatic patients are usually investigated employing several diagnostic tests, which should be appropriately selected and sequenced, taking into account their sensitivity, specificity, safety and cost. The objective of this paper is to evaluate the performance of the new diagnostic tests and their combination in rational diagnostic strategies. DESIGN AND METHODS: A literature review was made using a Medline(R) database search for the period 1988-1998 on the following key words in various combinations: diagnosis, diagnostic strategy, venous thrombosis, pulmonary embolism, venous thromboembolism. Results of a new study by our group on diagnosis of DVT in hospitalized patients are also discussed. RESULTS: In patients with symptoms or signs suggestive of DVT, compression ultrasound (CUS) appears to be the diagnostic test of first choice, since it is a noninvasive test with high specificity and sensitivity for proximal DVT (about 97%). When CUS gives a negative result it is usually recommended that the test is repeated after one week, since its sensitivity for calf DVT is poor. The positive and negative predictive values (PPV and NPV) of CUS in symptomatic outpatients can be improved if adequate consideration is given to clinical diagnosis, using a standardized model (ref. #9), which allows symptomatic outpatients to be categorized as having a high, moderate or low probability of DVT. In case of agreement between clinical diagnosis and CUS results, no further testing is needed: patients with high or intermediate clinical probability and positive CUS results are treated, while in patients with low clinical probability and negative CUS results the diagnosis of DVT is excluded. In the case of discrepancy between clinical diagnosis and CUS results, D-dimer test and/or venography are requested. However in patients who develop signs or symptoms of DVT in the hospital the clinical model does not work, and diagnosis should be based on an appropriate mix of CUS, D-dimer (DD) test and venography. In patients presenting with signs or symptoms of pulmonary embolism, the ventilation/perfusion (V/P) lung scan remains a pivotal diagnostic test, and pulmonary angiography the reference standard, but both methods have limitations and in recent years other diagnostic tests such as echocardiography, helical (or spiral) computerized tomography, and magnetic resonance imaging have been introduced into clinical practice. Moreover, all four diagnostic tools mentioned for DVT diagnosis can be considered. Several diagnostic strategies have been proposed and evaluated in comparative studies but there is still debate over the most efficient test combination or sequence. INTERPRETATION AND CONCLUSIONS: Diagnostic strategies which include adequate consideration of clinical diagnosis using standardized models have the potential of being more efficient for outpatients (but not for inpatients) with symptoms or signs suggesting DVT of lower limbs. For patients with suspected PE, several diagnostic strategies have been assessed: V/P lung scan remains a pivotal diagnostic test, but its limitations have been increasingly recognized and newer non-invasive techniques are gaining credit. A consensus is still to be reached over the most appropriate combination of diagnostic tests.
BACKGROUND: Computer-assisted diagnostic systems are not substantially more accurate than the clinician in the differential diagnosis of jaundice but may help in optimal selection and sequencing of tests. The present study aimed to assess with an electronic diagnostic tool the pattern of ordering tests and the diagnostic contribution and related financial cost of each test in jaundiced patients with pancreatobiliary carcinoma, in an effort to make the clinician's diagnostic behaviour more efficient and economical. METHODS: Clinical and diagnostic test data were prospectively gathered from 356 jaundiced patients with pancreatobiliary carcinoma and entered in a Bayesian diagnostic programme. The test results were added to the existing diagnostic evidence, and the programme calculated the diagnostic contribution of each test. RESULTS: A total of 1804 diagnostic tests were ordered. Quantitative assessment of the diagnostic contribution of each test showed that percutaneous transhepatic cholangiography and computed tomography were associated with the highest provision of information. The most cost-effective tests were ultrasonography and liver function tests. CONCLUSIONS: It is possible to determine objectively the diagnostic contribution of each test in establishing the diagnosis of pancreatobiliary carcinoma. The observed physician behaviour in ordering the various diagnostic tests might be improved with regard to its efficacy and its cost-effectiveness profile.
CONTEXT: The literature contains a large number of potential biases in the evaluation of diagnostic tests. Strict application of appropriate methodological criteria would invalidate the clinical application of most study results. OBJECTIVE: To empirically determine the quantitative effect of study design shortcomings on estimates of diagnostic accuracy. DESIGN AND SETTING: Observational study of the methodological features of 184 original studies evaluating 218 diagnostic tests. Meta-analyses on diagnostic tests were identified through a systematic search of the literature using MEDLINE, EMBASE, and DARE databases and the Cochrane Library (1996-1997). Associations between study characteristics and estimates of diagnostic accuracy were evaluated with a regression model. MAIN OUTCOME MEASURES: Relative diagnostic odds ratio (RDOR), which compared the diagnostic odds ratios of studies of a given test that lacked a particular methodological feature with those without the corresponding shortcomings in design. RESULTS: Fifteen (6.8%) of 218 evaluations met all 8 criteria; 64 (30%) met 6 or more. Studies evaluating tests in a diseased population and a separate control group overestimated the diagnostic performance compared with studies that used a clinical population (RDOR, 3.0; 95% confidence interval [CI], 2.0-4.5). Studies in which different reference tests were used for positive and negative results of the test under study overestimated the diagnostic performance compared with studies using a single reference test for all patients (RDOR, 2.2; 95% CI, 1.5-3.3). Diagnostic performance was also overestimated when the reference test was interpreted with knowledge of the test result (RDOR, 1.3; 95% CI, 1.0-1.9), when no criteria for the test were described (RDOR, 1.7; 95% CI, 1.1-2.5), and when no description of the population under study was provided (RDOR, 1.4; 95% CI, 1.1-1.7). CONCLUSION: These data provide empirical evidence that diagnostic studies with methodological shortcomings may overestimate the accuracy of a diagnostic test, particularly those including nonrepresentative patients or applying different reference standards.
OBJECTIVES: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance. Also to identify practical diagnostic algorithms for DVT, and estimate the diagnostic accuracy, clinical effectiveness and cost-effectiveness of each. DATA SOURCES: Electronic databases (to April 2004). A postal survey of hospitals in the UK. REVIEW METHODS: Selected studies were assessed against validated criteria. A postal survey of hospitals in the UK was undertaken to describe current practice and availability of tests, and identify additional diagnostic algorithms. Pooled estimates of sensitivity, specificity and likelihood ratios were obtained for each test using random effects meta-analysis. The effect of study-level covariates was explored using random effects metaregression. A decision-analytic model was used to combine estimates from the meta-analysis and estimate the diagnostic performance of each algorithm in a theoretical population of outpatients with suspected DVT. The net benefit of using each algorithm was estimated from a health service perspective, using cost--utility analysis, assuming thresholds of willingness to pay of pound 20,000 and pound 30,000 per quality-adjusted life-year (QALY). The model was analysed probabilistically and cost-effectiveness acceptability curves were generated to reflect uncertainty in estimated cost-effectiveness. RESULTS: Individual clinical features are of limited diagnostic value, with most likelihood ratios being close to 1. Wells clinical probability score stratifies proximal, but not distal, DVT into high-, intermediate- and low-risk categories. Unstructured clinical assessment by experienced clinicians may have similar performance to Wells score. In patients with clinically suspected DVT, D-dimer has 91% sensitivity and 55% specificity for DVT, although performance varies substantially between assays and populations. D-dimer specificity is dependent on pretest clinical probability, being higher in patients with a low clinical probability of DVT. Plethysmography and rheography techniques have modest sensitivity for proximal DVT, poor sensitivity for distal DVT, and modest specificity. Ultrasound has 94% sensitivity for proximal DVT, 64% sensitivity for distal DVT and 94% specificity. Computed tomography scanning has 95% sensitivity for all DVT (proximal and distal combined) and 97% specificity. Magnetic resonance imaging has 92% sensitivity for all DVT and 95% specificity. The diagnostic performance of all tests is worse in asymptomatic patients. The most cost-effective algorithm discharged patients with a low Wells score and negative D-dimer without further testing, and then used plethysmography alongside ultrasound, with venography in selected cases, to diagnose the remaining patients. However, the cost-effectiveness of this algorithm was dependent on assumptions of test independence being met and the ability to provide plethysmography at relatively low cost. Availability of plethysmography and venography is currently limited at most UK hospitals, so implementation would involve considerable reorganisation of services. Two algorithms were identified that offered high net benefit and would be feasible in most hospitals without substantial reorganisation of services. Both involved using a combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of pound 10,000 or pound 20,000 per QALY the optimal strategy involved discharging patients with a low or intermediate Wells score and negative D-dimer, ultrasound for those with a high score or positive D-dimer, and repeat scanning for those with positive D-dimer and a high Wells score, but negative initial scan. For thresholds of pound 30,000 or more a similar strategy, but involving repeat ultrasound for all those with a negative initial scan, was optimal. CONCLUSIONS: Diagnostic algorithms based on a combination of Wells score, D-dimer and ultrasound (with repeat if negative) are feasible at most UK hospitals and are among the most cost-effective. Use of repeat scanning depends on the threshold for willingness to pay for health gain. Further diagnostic testing for patients with a low Wells score and negative D-dimer is unlikely to represent a cost-effective use of resources. Recommendations for research include the evaluation of the costs and outcomes of using the optimal diagnostic algorithms in routine practice, the development and evaluation of algorithms appropriate for specific groups of patients with suspected DVT, such as intravenous drug abusers, pregnant patients and those with previous DVT, the evaluation of the role of plethysmography: interaction with other diagnostic tests, outcome of low-risk patients with negative plethysmography and measurement of the costs of providing plethysmography, and methodological research into the incorporation of meta-analytic data into decision-analytic modelling.