The diagnostic dilemma of hyperintense fetal lung on prenatal MRI : 12.03

Purpose: In the last years, MRI appears as a complementary diagnostic method to US in the diagnosis of congenital lung lesions. Focal homogeneous pulmonary hyperintensity on T2-WI constitutes a frequent pattern observed. Our purpose is to determine if this finding is associated with a characteristic pulmonary lesion. Materials and methods: Between 01.01.00 and 31.12.07, a total of 50 prenatal MRI in fetuses with echographic diagnosis of thoracic pathology were performed in our institution, including 12 cases of suspected congenital pulmonary lesions. Prenatal images were correlated with post-natal diagnosis. Results: In 12 cases, fetal MRI detected congenital pulmonary lesions. In 8 patients, typical signs (cystic lesions, septations, anomalous vasculature) clearly suggested a specific pathology. In 4 cases, MRI showed a focal homogeneous increase of the signal intensity (SI) on T2-WI of the pathologic lung related to the normal one. The final diagnosis of these fetuses included 1 patient with congenital cystic adenomatoid malformation type III, 1 patient with segmental emphysema and 2 cases of bronchial atresia. In all 4 cases, a significant post-natal reduction of the lesion size related to prenatal MRI studies was observed. Conclusion: Our study suggests that a focal increment of the SI of the lung on T2-WI is a non specific sign of congenital lung disease, present in different pathologies. Therefore, a prospective diagnosis is not possible.

Does introduction of thresholds in decision aids benefit the patient?: Comparison between findings-based and threshold-based diagnostic decision aids.

PURPOSE: To assess how different diagnostic decision aids perform in terms of sensitivity, specificity, and harm. METHODS: Four diagnostic decision aids were compared, as applied to a simulated patient population: a findings-based algorithm following a linear or branched pathway, a serial threshold-based strategy, and a parallel threshold-based strategy. Headache in immune-compromised HIV patients in a developing country was used as an example. Diagnoses included cryptococcal meningitis, cerebral toxoplasmosis, tuberculous meningitis, bacterial meningitis, and malaria. Data were derived from literature and expert opinion. Diagnostic strategies' validity was assessed in terms of sensitivity, specificity, and harm related to mortality and morbidity. Sensitivity analyses and Monte Carlo simulation were performed. RESULTS: The parallel threshold-based approach led to a sensitivity of 92% and a specificity of 65%. Sensitivities of the serial threshold-based approach and the branched and linear algorithms were 47%, 47%, and 74%, respectively, and the specificities were 85%, 95%, and 96%. The parallel threshold-based approach resulted in the least harm, with the serial threshold-based approach, the branched algorithm, and the linear algorithm being associated with 1.56-, 1.44-, and 1.17-times higher harm, respectively. Findings were corroborated by sensitivity and Monte Carlo analyses. CONCLUSION: A threshold-based diagnostic approach is designed to find the optimal trade-off that minimizes expected harm, enhancing sensitivity and lowering specificity when appropriate, as in the given example of a symptom pointing to several life-threatening diseases. Findings-based algorithms, in contrast, solely consider clinical observations. A parallel workup, as opposed to a serial workup, additionally allows for all potential diseases to be reviewed, further reducing false negatives. The parallel threshold-based approach might, however, not be as good in other disease settings.

Comment la sérologie peut-elle aider à l'établissement du diagnostic des parasites [How can serology contribute to the diagnosis of parasitic diseases?].

From a technical standpoint the most widely used tests for serology include the ELISA (enzyme linked immunosorbent assay), the IFA (indirect fluorescence assay), and the immunoblot. ELISA tests are widely used as screening assays since they harbor a high sensitivity. The main pitfall of serologies is the frequency of cross-reactions, especially between the different helminths. This is why positive results should be confirmed by a second test method with a higher specificity. Results need also to be put in the perspective of the patient history, clinical signs and laboratory findings. Serological tests are most appropriate when the parasite cannot be documented by direct examination (by eye or under the microscope) and during the pre-patent period. Serologies for parasites are also useful when an unexplained eosinophilia is present.

Le point sur l'ergométrie en 2012 dans le diagnostic de la maladie coronarienne.

Background In patients presenting with acute cardiac symptoms, abnormal ECG and raised troponin, myocarditis may be suspected after normal angiography. Aims To analyse cardiac magnetic resonance (CMR) findings in patients with a provisional diagnosis of acute coronary syndrome (ACS) in whom acute myocarditis was subsequently considered more likely. Methods and results 79 patients referred for CMR following an admission with presumed ACS and raised serum troponin in whom no culprit lesion was detected were studied. 13% had unrecognised myocardial infarction and 6% takotsubo cardiomyopathy. The remainder (81%) were diagnosed with myocarditis. Mean age was 45615 years and 70% were male. Left ventricular ejection fraction (EF) was 58610%; myocardial oedema was detected in 58%. A myocarditic pattern of late gadolinium enhancement (LGE) was detected in 92%. Abnormalities were detected more frequently in scans performed within 2 weeks of symptom onset: oedema in 81% vs 11% (p<0.0005), and LGE in 100% vs 76% (p<0.005). In 20 patients with both an acute (<2 weeks) and convalescent scan (>3 weeks), oedema decreased from 84% to 39% (p<0.01) and LGE from 5.6 to 3.0 segments (p¼0.005). Three patients presented with sustained ventricular tachycardia, another died suddenly 4 days after admission and one resuscitated 7 weeks following presentation. All 5 patients had preserved EF. Conclusions Our study emphasises the importance of access to CMR for heart attack centres. If myocarditis is suspected, CMR scanning should be performed within 14 days. Myocarditis should not be regarded as benign, even when EF is preserved.

Diagnostic and ethical challenges in disorders of consciousness and locked-in syndrome: a survey of German neurologists.

Diagnosis and decisions on life-sustaining treatment (LST) in disorders of consciousness, such as the vegetative state (VS) and the minimally conscious state (MCS), are challenging for neurologists. The locked-in syndrome (LiS) is sometimes confounded with these disorders by less experienced physicians. We aimed to investigate (1) the application of diagnostic knowledge, (2) attitudes concerning limitations of LST, and (3) further challenging aspects in the care of patients. A vignette-based online survey with a randomized presentation of a VS, MCS, or LiS case scenario was conducted among members of the German Society for Neurology. A sample of 503 neurologists participated (response rate 16.4%). An accurate diagnosis was given by 86% of the participants. The LiS case was diagnosed more accurately (94%) than the VS case (79%) and the MCS case (87%, p < 0.001). Limiting LST for the patient was considered by 92, 91, and 84% of the participants who accurately diagnosed the VS, LiS, and MCS case (p = 0.09). Overall, most participants agreed with limiting cardiopulmonary resuscitation; a minority considered limiting artificial nutrition and hydration. Neurologists regarded the estimation of the prognosis and determination of the patients' wishes as most challenging. The majority of German neurologists accurately applied the diagnostic categories VS, MCS, and LiS to case vignettes. Their attitudes were mostly in favor of limiting life-sustaining treatment and slightly differed for MCS as compared to VS and LiS. Attitudes toward LST strongly differed according to circumstances (e.g., patient's will opposed treatment) and treatment measures.

Diagnostic des maladies infectieuses: place des "point of care tests" (POCT) [Use of POCT (point of care tests) in the diagnosis of infectious diseases]

Les POCT (point of care tests) ont un grand potentiel d'utilisation en médecine infectieuse ambulatoire grâce à leur rapidité d'exécution, leur impact sur l'administration d'antibiotiques et sur le diagnostic de certaines maladies transmissibles. Certains tests sont utilisés depuis plusieurs années (détection de Streptococcus pyogenes lors d'angine, anticorps anti-VIH, antigène urinaire de S. pneumoniae, antigène de Plasmodium falciparum). De nouvelles indications concernent les infections respiratoires, les diarrhées infantiles (rotavirus, E. coli entérohémorragique) et les infections sexuellement transmissibles. Des POCT, basés sur la détection d'acides nucléiques, viennent d'être introduits (streptocoque du groupe B chez la femme enceinte avant l'accouchement et la détection du portage de staphylocoque doré résistant à la méticilline). POCT have a great potential in ambulatory infectious diseases diagnosis, due to their impact on antibiotic administration and on communicable diseases prevention. Some are in use for long (S. pyogenes antigen, HIV antibodies) or short time (S. pneumoniae antigen, P. falciparum). The additional major indications will be community-acquired lower respiratory tract infections, infectious diarrhoea in children (rotavirus, enterotoxigenic E. coli), and hopefully sexually transmitted infections. Easy to use, these tests based on antigen-antibody reaction allow a rapid diagnosis in less than one hour; the new generation of POCT relying on nucleic acid detection are just introduced in practice (detection of GBS in pregnant women, carriage of MRSA), and will be extended to many pathogens

How to measure cortical folding from MR images: a step-by-step tutorial to compute local gyrification index.

Cortical folding (gyrification) is determined during the first months of life, so that adverse events occurring during this period leave traces that will be identifiable at any age. As recently reviewed by Mangin and colleagues(2), several methods exist to quantify different characteristics of gyrification. For instance, sulcal morphometry can be used to measure shape descriptors such as the depth, length or indices of inter-hemispheric asymmetry(3). These geometrical properties have the advantage of being easy to interpret. However, sulcal morphometry tightly relies on the accurate identification of a given set of sulci and hence provides a fragmented description of gyrification. A more fine-grained quantification of gyrification can be achieved with curvature-based measurements, where smoothed absolute mean curvature is typically computed at thousands of points over the cortical surface(4). The curvature is however not straightforward to comprehend, as it remains unclear if there is any direct relationship between the curvedness and a biologically meaningful correlate such as cortical volume or surface. To address the diverse issues raised by the measurement of cortical folding, we previously developed an algorithm to quantify local gyrification with an exquisite spatial resolution and of simple interpretation. Our method is inspired of the Gyrification Index(5), a method originally used in comparative neuroanatomy to evaluate the cortical folding differences across species. In our implementation, which we name local Gyrification Index (lGI(1)), we measure the amount of cortex buried within the sulcal folds as compared with the amount of visible cortex in circular regions of interest. Given that the cortex grows primarily through radial expansion(6), our method was specifically designed to identify early defects of cortical development. In this article, we detail the computation of local Gyrification Index, which is now freely distributed as a part of the FreeSurfer Software (http://surfer.nmr.mgh.harvard.edu/, Martinos Center for Biomedical Imaging, Massachusetts General Hospital). FreeSurfer provides a set of automated reconstruction tools of the brain's cortical surface from structural MRI data. The cortical surface extracted in the native space of the images with sub-millimeter accuracy is then further used for the creation of an outer surface, which will serve as a basis for the lGI calculation. A circular region of interest is then delineated on the outer surface, and its corresponding region of interest on the cortical surface is identified using a matching algorithm as described in our validation study(1). This process is repeatedly iterated with largely overlapping regions of interest, resulting in cortical maps of gyrification for subsequent statistical comparisons (Fig. 1). Of note, another measurement of local gyrification with a similar inspiration was proposed by Toro and colleagues(7), where the folding index at each point is computed as the ratio of the cortical area contained in a sphere divided by the area of a disc with the same radius. The two implementations differ in that the one by Toro et al. is based on Euclidian distances and thus considers discontinuous patches of cortical area, whereas ours uses a strict geodesic algorithm and include only the continuous patch of cortical area opening at the brain surface in a circular region of interest.

Le pyoderma gangrenosum: pathologie rare ou diagnostic omis [Pyoderma gangrenosum: a rare pathology or an omitted diagnosis?]

Pyoderma gangrenosum is a rare pathology of uncertain etiology. It is an inflammatory dermatosis that causes cutaneous necrosis with a characteristically rapid evolution. No precise diagnosis criteria has been established and pyoderma gangrenosum remains an exclusion diagnosis. In 40 to 50% of the cases, the evolution of pyoderma gangrenosum can be worsened by a nonspecific external stimulus such as a trauma or a surgery. This phenomenon, called pathergy, conduces to avoid any surgical excision of the lesion. However, the diagnosis is often omitted and the rapid evolution of the cutaneous necrosis forces the surgeon to perform a surgical debridement of the wound. It causes a pejoration of the lesion. It can have disastrous consequences. We present here three different case reports.

A clinical pattern-based etiological diagnostic strategy for sensory neuronopathies: a French collaborative study.

Sensory neuronopathies (SNNs) encompass paraneoplastic, infectious, dysimmune, toxic, inherited, and idiopathic disorders. Recently described diagnostic criteria allow SNN to be differentiated from other forms of sensory neuropathy, but there is no validated strategy based on routine clinical investigations for the etiological diagnosis of SNN. In a multicenter study, the clinical, biological, and electrophysiological characteristics of 148 patients with SNN were analyzed. Multiple correspondence analysis and logistic regression were used to identify patterns differentiating between forms of SNNs with different etiologies. Models were constructed using a study population of 88 patients and checked using a test population of 60 cases. Four patterns were identified. Pattern A, with an acute or subacute onset in the four limbs or arms, early pain, and frequently affecting males over 60 years of age, identified mainly paraneoplastic, toxic, and infectious SNN. Pattern B identified patients with progressive SNN and was divided into patterns C and D, the former corresponding to patients with inherited or slowly progressive idiopathic SNN with severe ataxia and electrophysiological abnormalities and the latter to patients with idiopathic, dysimmune, and sometimes paraneoplastic SNN with a more rapid course than in pattern C. The diagnostic strategy based on these patterns correctly identified 84/88 and 58/60 patients in the study and test populations, respectively.

Riesenzellarteriitis : Ätiologische Erkenntnisse und diagnostische Herausforderung für den Pathologen [Giant cell arteritis : Etiological knowledge and diagnostic challenge for pathologists].

Giant cell arteritis is a potentially systemic disease of medium-sized and large caliber arteries, showing a preferential manifestation in the extracranial branches of the carotid artery. The diagnosis is oriented to clinical and histomorphological criteria which will be critically reviewed. Particular emphasis is placed on the differentiation from normal aging processes and from healing stages under steroid therapy. In addition, the advances in our understanding of the disease pathomechanism during the last 10 years will be briefly presented as the basis for the hitherto empiric steroid treatment.

Calprotectine fécale: outil diagnostique dans les maladies inflammatoires chroniques de l'intestin [Fecal calprotectin: a diagnostic tool for inflammatory bowel disease].

Fecal calprotectin (FC) is a valid biomarker to discriminate with a good sensitivity and specificity the presence of mucosal lesions of the gastrointestinal tube (e.g. ulcers in the context of inflammatory bowel disease (IBD)) from functional disorders (e.g. irritable bowel syndrome). FC is not specific for IBD and can be elevated also in gastrointestinal infections, ischemic colitis or neoplasia. An elevated FC should stimulate further investigations, notably an endoscopic workup. The level of FC correlates with the endoscopic score in Crohn's disease and ulcerative colitis. The correlation of FC and the endoscopic severity is better than the one of CRP or blood leukocytes. Thus, FC can also be used in the follow-up of IBD patients.

Simpson-Golabi-Behmel syndrome type 1 in a 27-week macrosomic preterm newborn: the diagnostic value of rib malformations and index nail and finger hypoplasia.

The Simpson-Golabi-Behmel syndrome type 1 (SGBS1, OMIM #312870) is an X-linked overgrowth condition comprising abnormal facial appearance, supernumerary nipples, congenital heart defects, polydactyly, fingernail hypoplasia, increased risk of neonatal death and of neoplasia. It is caused by mutation/deletion of the GPC3 gene. We describe a macrosomic 27-week preterm newborn with SGBS1 who presents a novel GPC3 mutation and emphasize the phenotypic aspects which allow a correct diagnosis neonatally in particular the rib malformations, hypoplasia of index finger and of the same fingernail, and 2nd-3rd finger syndactyly.