[Evaluation of associations between barn characteristics, results of barn climate parameter measurements and health indicators in Swiss veal calf herds]. / Evaluation der Zusammenhänge zwischen Stallmerkmalen, gemessenen Stallklimaparametern und Indikatoren für Tiergesundheit in Schweizer Kälbermastbetrieben.

INTRODUCTION: Easy-to-use digital devices to measure climate parameters that can also be used in calf barns have become available commercially in recent years. Data collected in a prospective cohort study in 43 Swiss veal calf operations were evaluated with regard to validity of measured climate parameters, potential associations of those with barn features, and relationships between values of climate parameters and barn characteristics, respectively, with indicators of calf health. Barn parameters, such as ventilation system, access to an outdoor pen and barn size, were recorded, and temperature, air humidity, ammonia and carbone dioxide concentrations were measured at five different locations in each barn during an average of six farm visits over a year. Furthermore, continuous measurements of temperature and humidity (over a period of 72 hours each) were performed once in summer and once in winter in each farm. Whether barn parameters and measured barn climate values are associated as significant risk factors with indicators of calf health (antimicrobial use, mortality and daily weight gain) was explored with statistical methods. Values outside the optimal range were observed for all parameters measured punctually during farm visits and in all seasons. Values of temperature and humidity outside the optimal range were observed more often by continuous than by punctual measurements. Relevant correlations were observed neither among the barn climate values measured punctually nor among measured barn climate values and number of calves, barn surface, bedded surface and barn volume. High maximal group size and presence of mechanic ventilation were positively associated with high antimicrobial use, and high maximal group size and high number of fattening groups were associated with mortality >3%. Farms in lowland regions and high air volume per calf were positively associated with daily weight gain. None of the measured barn climate parameters was associated with the calf health indicators antimicrobial use, mortality and daily weight gain. Therefore, climate parameter measurements appear inadequate to predict calf health in veal fattening operations. The present results show that these (easily) measured parameters are difficult to interpret and should be considered critically.

INTRODUCTION: Des instruments de mesure digitaux faciles à l'emploi pour les paramètres climatiques, qui peuvent aussi être utilisés dans les étables, sont disponibles depuis quelque temps.Afin d'évaluer la validité des valeurs de paramètres du climat mesurées, d'éventuelles associations de ces mesures avec certaines caractéristiques des étables, et les relations des mesures de paramètres associés au climat, respectivement des spécificités des étables, avec des indicateurs de santé animale, des données récoltées dans le cadre d'une étude prospective dans 43 exploitations d'engraissement de veaux en Suisse ont été analysées. D'une part, différents paramètres des étables (tels que le système d'aération, l'accès à un enclos externe, la surface de l'étable) ont été répertoriés. D'autre part, des mesures ponctuelles de la température, de l'humidité de l'air et des concentrations d'ammoniac et de dioxide de carbone ont été effectuées à cinq endroits de chaque étable lors de visites d'exploitation (en moyenne six par ferme sur une durée d'une année). De plus, des mesures continues de la température et de l'humidité ont été conduites sur 72 heures, une fois en été et une fois en hiver, dans chaque exploitation. À l'aide de méthodes statistiques, on a évalué si les caractéristiques des étables et les valeurs de climat mesurées sont associées en tant que facteurs de risque significatifs avec les indicateurs de santé animale (usage d'antibiotiques, mortalité et gain de poids journalier). Lors des mesures ponctuelles, des valeurs en dehors des domaines optimaux ont été observées pour tous les paramètres mesurés et à chaque saison. Des valeurs en dehors des domaines optimaux pour la température et l'humidité ont été constatées plus souvent par les mesures continues que par les mesures ponctuelles. Aucune corrélation significatrice n'a été observée entre les valeurs des paramètres de climat mesurées ponctuellement ou entre les valeurs des paramètres du climat mesurées et le nombre de veaux présents dans l'étable, la surface totale de l'étable, la surface paillée ou le volume de l'étable. Les groupes comptant beaucoup de veaux et la présence d'une ventilation mécanique étaient associés positivement à un usage élevé d'antibiotiques. Les groupes comprenant beaucoup de veaux et la présence d'un grand nombre de groupes étaient associés avec un taux de mortalité supérieur à 3%. Les exploitations en zone de plaine et le volume d'air par veau étaient associés positivement avec le gain de poids journalier. Aucun des paramètres de climat mesurés ne montrait d'association avec les indicateurs de santé animale (usage des antibiotiques, mortalité et gain de poids journalier). Ils semblent donc être inadéquats pour évaluer la santé des veaux dans des exploitations d'engraissement. Nos résultats montrent que les mesures de paramètres du climat sont difficiles à interpréter et doivent être considérés de manière critique.

Limited CD4+ T-cell renewal in early HIV-1 infection: effect of highly active antiretroviral therapy.

We show that the fraction of proliferating CD4+ lymphocytes is similar in HIV-infected subjects in the early stage of disease and in HIV-negative subjects, whereas the fraction of proliferating CD8+ lymphocytes is increased 6.8-fold in HIV-infected subjects. After initiation of antiviral therapy, there is a late increase in proliferating CD4+ T cells associated with the restoration of CD4+ T-cell counts. These results provide strong support for the idea of limited CD4+ T-cell renewal in the early stage of HIV infection and indicate that after effective suppression of virus replication, the mechanisms of CD4+ T-cell production are still functional in early HIV infection.

Prevalence and antimicrobial resistance of opportunistic pathogens associated with bovine respiratory disease isolated from nasopharyngeal swabs of veal calves in Switzerland.

The composition of the bacterial flora in the calf nasopharynx might influence the risk of bovine respiratory disease (BRD). The aims of the present study were, firstly, to investigate the prevalence of bacteria potentially involved in BRD in the nasopharynx of veal calves and to identify associated risk factors for their presence, and, secondly, to provide data on antimicrobial resistance levels in these bacteria. Deep nasopharyngeal swabs were collected from veal calves on 12 Swiss farms over a period of one year by non-random, but systematic sampling for isolation of Pasteurellaceae and Mycoplasma (M.) bovis and dispar. Associations of potential risk factors with occurrence of these bacteria were tested in multivariable mixed logistic regression analyses, based on information gained from extensive questionnaires completed with the farmers. Antimicrobial susceptibility testing was performed for Pasteurellaceae by broth microdilution method to obtain minimal inhibitory concentrations (MIC). Pasteurellaceae, including Pasteurella (P.) multocida, Mannheimia (M.) haemolytica, Bisgaard Taxon 39 and Histophilus (H.) somni, were almost twice as prevalent as M. bovis and dispar in this study. Continuous stocking was a risk factor for the presence of Pasteurellaceae, especially when calves originated from more than six suppliers. In young calves (≤ 91 days), feeding of California Mastitis Test (CMT) positive milk was an additional risk factor for the presence of Pasteurellaceae whereas transport of calves by farmers and livestock traders (as opposed to transport only by farmers) increased the risk in older calves (> 91 days). Risk factors for the presence of M. bovis/dispar were higher number of calves per drinking nipple in young calves, and no access to an outside pen and feeding of CMT positive milk in older calves, respectively. While further research will have to investigate the observed associations in more detail, this suggests that management can play an important role in the prevalence of nasopharyngeal bacteria with a potential subsequent involvement in BRD. Antimicrobial resistance differed between the three bacterial species tested in this study and was highest to oxytetracycline and spectinomycin in P. multocida, oxytetracycline and penicillin in M. haemolytica, and ampicillin and penicillin in H. somni. Only two European VetCAST breakpoints (for florfenicol in P. multocida and M. haemolytica) have been published to date, matching the MIC distribution of the present isolate populations well, in contrast to certain commonly applied American Clinical and Laboratory Institute interpretive criteria. This highlights the potential for further refinement of clinical breakpoints in veterinary medicine.

[Transport of veal calves from birth farms to veal farms and calf management in Swiss dairy farms]. / Transporte von Mastkälbern vom Geburts- auf den Mastbetrieb und Kälbermanagement in Schweizer Geburtsbetrieben.

INTRODUCTION: The calf transports of 34 veal farms were documented over a one-year period in order to describe the transport from dairy to veal farms. Veal farms were visited four to eight times, and general farm management data and information on calf purchase were collected. Thirty-five transports were accompanied and documented in detail by the project team. Whenever possible during the accompanied transports, a questionnaire on calf management prior to purchase (calving location, colostrum feeding, vaccinations, iron and selenium supplementation) was filled in with the manager of the dairy (birth) farm. Unaccompanied transports were recorded using a form completed by the veal farmers and the transporters. Information was collected on the number and origin of the calves, transport duration and distance, and stops on farms and markets. A total of 721 transports from dairy to veal farms (531 transports by veal farmers and 190 by suppliers/livestock traders) were documented in the course of the project. Six veal farmers always collected and transported their own calves, nine received their calves from cattle traders only, and 19 used both systems. Veal farmers transported a median of 2.0 (1-21 calves) and traders 3.0 calves (1-74 calves) per transport. The median number of dairy farms per 10 transported calves was 10.0 (1.2-10 dairy farms per 10 transported calves) for transports performed by veal farmers, and 10.0 (2.5-10 dairy farms per 10 transported calves) by traders. The median transport duration was 20.0 minutes (1-330 minutes) with veal farmers and 45.0 minutes (2-414 minutes) with traders. The median available surface per calf during transport was 2 m2 (0.4-6 m2) in transports by veal farmers and 0.6 m2 (0.4-2.7 m2) in those by traders. No bedding was provided on three transports performed by veal farmers although this is prescribed by law. Intranasal vaccination against respiratory disease was performed in 7% of the 88 birth farms included in the study.

INTRODUCTION: Afin de documenter les transports de veaux des exploitations de naissance aux exploitations d'engraissement, les transports dans 34 fermes d'engraissement ont été documentés pendant un an. Les exploitations d'engraissement ont été visitées quatre à huit fois au cours de cette période et des données générales ont été recueillies sur l'exploitation et sur l'achat des veaux. Trente-cinq transports ont été accompagnés et documentés avec précision par l'équipe du projet. Si possible, un questionnaire sur la gestion des veaux avant la vente (lieu de naissance, apport en colostrum, vaccinations, administration de fer et de sélénium) a été rempli avec les responsables de l'exploitation de naissance lors des transports accompagnés. Les autres transports (non accompagnés) ont été documentés à l'aide d'un formulaire que les agriculteurs ont rempli avec les transporteurs. Des informations ont été recueillies sur le nombre et l'origine des veaux, la durée et la distance de transport, ainsi que les arrêts dans les fermes et les marchés. Au total, 721 transports de l'exploitation de naissance à celle d'engraissement ont pu être documentés au cours du projet (531 transports par les engraisseurs eux-mêmes et 190 par des fournisseurs/marchands de bétail). Sur les 34 engraisseurs, six allaient toujours chercher leurs veaux eux-mêmes, neuf les achetaient toujours à un fournisseur, et 19 faisaient les deux. Les engraisseurs transportaient un médian de 2,0 veaux (1-21 veaux) et les fournisseurs de 3,0 veaux (1-74 veaux) par transport. Le nombre médian d'exploitations de naissance par 10 veaux transportés était 10,0 (1,2 à 10 exploitations par 10 veaux) pour les transports effectués par les engraisseurs et de 10,0 pour ceux effectués par les fournisseurs (2,5 à 10 exploitations par 10 veaux). La durée médiane des transports était de 20,0 minutes (1-330 minutes) pour les engraisseurs et de 45,0 minutes (2-414 minutes) pour les marchands de bétail. Pour les transports accompagnés, la surface médiane par veau était de 2 m2 (0,4 à 6 m2) pour les engraisseurs et de 0,6 m2 (0,4 à 2,7 m2) pour les marchands. Il n'y avait pas de litière sur trois transports d'engraisseurs, bien que cela soit exigé par la loi. Une vaccination intranasale contre les maladies respiratoires était réalisée dans 7% des 88 fermes de naissance pour lesquelles un questionnaire a été rempli.

Effects of management practices, animal transport and barn climate on animal health and antimicrobial use in Swiss veal calf operations.

To assess the effects of transport, management factors and barn climate on calf health, 43 Swiss veal farms (11 large farms fattening ≥100 calves and 32 small farms fattening >20 but <100 calves per year) were monitored in a prospective cohort study over a period of one year. Detailed questionnaires on farm structure, management, housing system and animal health were filled out with the farmers during bimonthly visits, and barn temperature, humidity, ammonia and CO2 concentrations were measured. Temperature and humidity were also measured continuously over 72 h once each in winter and summer. In addition, calf purchase and transport from birth farm to fattening unit were documented by the farmers, and the study team accompanied one transport per farm whenever possible. Antimicrobial treatment incidence was calculated from the used daily dose (TIUDD). Risk factors for mortality, average daily weight gain (ADG) and antimicrobial use, as well as factors related to transport and barn climate measures were evaluated with mixed regression models. The overall mortality rate was 5.1% (6.2% in large herds and 3.1% in small ones). Identified risk factors for mortality >3% included a lower number of calves fattened per year and a good hygiene of the feeder. This surprising result was likely due to the fact that the threshold of 3% mortality was rather exceeded in smaller farms. Furthemore, higher temperature variation (range between maximal and minimal temperature over 3 measurement days) in the calf pen was associated with mortality >3% in the univariable analysis. The overall mean ADG was 1.40 ± 0.16 kg. Calf purchase was significantly associated with decreased ADG. The median overall TIUDD was eight daily doses per calf and year (2.1 in small farms and 26 in large farms, respectively); the main indication for treatment was respiratory disease (81.1%). Risk factors for increased TI were no quarantine upon arrival, access to an outside pen, higher numbers of calves per drinking nipple, mechanical ventilation, vaccination against bovine respiratory disease, and a maximum ammonia value >10 ppm in the calf pen. In addition, a higher number of birth farms and calf purchase from markets were associated with increased TI in the univariable analysis. The identified risk factors associated with increased TI and mortality and with decreased ADG should be addressed in priority in veal calf operations to improve calf health and reduce antimicrobial use.

Associations between antimicrobial treatment modalities and antimicrobial susceptibility in Pasteurellaceae and E. coli isolated from veal calves under field conditions.

Antimicrobial consumption, with bovine respiratory disease as main indication, is higher in the veal calf industry compared to other livestock production branches. The aim of the present study was to investigate possible associations between antimicrobial drug use and resistance in Pasteurellaceae and indicator Escherichia (E.) coli from veal calves under field conditions in a prospective trial. Over a period of one year, nasopharyngeal and rectal swabs were collected from 2587 animals on 12 and 43 farms, respectively. Antimicrobial susceptibility testing was performed on 346 Mannheimia (M.) haemolytica, 1162 Pasteurella (P.) multocida and 2138 E. coli. Drug use was quantified as treatment incidence for each farm based on the used daily dose methodology (TIUDD), separately for group and individual treatments, and for antimicrobial classes. In multivariable mixed logistic regression analyses, risk factors could be identified for reduced susceptibility to certain antimicrobial classes. Group treatment was generally associated with higher rates of not susceptible (NS) M. haemolytica and P. multocida and non-wildtype (non-WT) E. coli. Individual treatment was associated with less NS and non-WT isolates. Age and entry protocol were important confounders with younger animals showing higher rates of NS and non-WT strains. The present findings suggest that, under field conditions, targeted individual treatment of calves can reduce the development of antimicrobial resistance compared to oral group treatment. For the different microorganisms, risk factors for resistance were partially different. This demonstrates that indicator organisms like E. coli do not necessarily reflect the associations observed in respiratory pathogens.

CT angiography and perfusion CT in cerebral vasospasm after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: We investigated the association of multisection CT angiography (MSCTA) and perfusion CT (PCT) for the characterization of vasospasm secondary to aneurysmal subarachnoid hemorrhage. MATERIALS AND METHODS: Among 27 patients with symptomatic cerebrovascular vasospasm investigated by digital subtraction angiography (DSA), 18 underwent both cerebral PCT and MSCTA. For the remaining 9, only PCT or MSCTA could be performed. MSCTA was compared with DSA for the detection and characterization of vasospasm on 286 intracranial arterial segments. PCT maps were visually reviewed for mean transit time, relative cerebral blood flow, and relative cerebral blood volume abnormalities and were qualitatively compared with the corresponding regional vasospasm detected by DSA. RESULTS: Vasospasm was grouped into 2 categories: mild-moderate and severe. The depiction of vasospasm by MSCTA showed the best sensitivity, specificity, and accuracy at the level of the A2 and M2 arterial segments (100% for each), in contrast to the carotid siphon (45%, 100%, and 85% respectively). The characterization of vasospasm severity by MSCTA showed a sensitivity, specificity, and accuracy of 86.8%, 96.8%, and 95.2%, respectively, for mild-moderate vasospasm, and 76.5%, 99.5%, and 97.5%, respectively, for severe vasospasm. The PCT abnormalities were related to severe vasospasm in 9 patients and to mild-to-moderate vasospasm in 2. The sensitivity, specificity, and accuracy of PCT in detecting vasospasm were 90%, 100%, and 92.3%, respectively, for severe vasospasm, and 20%, 100%, and 38.5%, respectively, for mild-moderate vasospasm. CONCLUSION: MSCTA/PCT can assess the location and severity of cerebrovascular vasospasm and its related perfusion abnormalities. It can identify severe vasospasm with risk of delayed ischemia and can thus guide the invasive treatment.

Cerebral vascular autoregulation assessed by perfusion-CT in severe head trauma patients.

PURPOSE: To use perfusion-CT technique in order to characterize cerebral vascular autoregulation in a population of severe head trauma patients with features of cerebral edema either on the admission or on the follow-up conventional noncontrast cerebral CT. MATERIAL AND METHODS: A total of 80 perfusion-CT examinations were obtained in 42 severe head trauma patients with features of cerebral edema on conventional noncontrast cerebral CT, either on admission or during follow-up. Perfusion-CT results, i.e. the regional cerebral blood volume (rCBV) and flow (rCBF), were correlated with the mean arterial pressure (MAP) measured during each perfusion-CT examination. Ratios were defined to integrate the concept of cerebral vascular autoregulation, and cluster analysis performed, which allowed identification of different subgroups of patients. MAP values and perfusion-CT results in these groups were compared using Kruskal-Wallis and Wilcoxon (Mann-Whitney) tests. Moreover, the functional outcome of the 42 patients was evaluated 3 months after trauma on the basis of the Glasgow Outcome Scale (GOS) score and similarly compared between groups. RESULTS: Three main groups of patients were identified: 1) 22 perfusion-CT examinations were collected in 13 patients, characterized by high rCBV and rCBF values and by significant dependence of perfusion-CT rCBV and rCBF results on MAP values (p<0.001), 2) 23 perfusion-CT examinations collected in 19 patients showing perfusion-CT results similar to control trauma subjects, and 3) 33 perfusion-CT collected in 16 patients, with low rCBV and rCBF values and near-independence of perfusion-CT results with respect to MAP values. The first group was interpreted as showing impaired cerebral vascular autoregulation, which was preserved in the third group. The second group was associated with the best functional outcome; it was linked to the first group, because eight patients went from one group to the other from admission to follow-up. CONCLUSION: Perfusion-CT in severe head trauma patients was able to provide direct and quantitative assessment of cerebral vascular autoregulation with a single measurement. It could hence be used as a guide for brain edema therapy, as well as to monitor the treatment efficiency.

[CT utilisation in Switzerland: frequency and secular trends]. / Pratique du scanner en Suisse: fréquence et évolution temporelle.

PURPOSE: This study analyzes CT examinations in Switzerland. MATERIALS AND METHODS: Using different sources (administrative data on the equipment, a 1998 nationwide inquiry into practices, and data provided by the Swiss University Hospitals of Basel, Zurich, and Lausanne), we determined the frequency of CT examinations (hospitals and private radiologists) in 1998 according to different descriptive variables and studied the progression in CT use over time. RESULTS: CT scanners increased by 7% between 1998 and 2004. The average annual number of CT examinations in 1998 was 46.3/1000 population, 3.4% of all radiological examinations in Switzerland in 1997-1998. The most frequent examination was CT of the skull (24%), while private radiology institutes perform more CTs of the spine. More CT examinations were performed for men than for women (sex ratio M/F=1.17). The average annual increase in CT in Swiss hospitals varied from 8% for Basel to 18% for Lausanne. Finally, the proportion of pediatric examinations was 5%; their numbers appear to be stabilizing. CONCLUSION: There is a significant increase in CT examinations. It is hoped that our study will heighten awareness among doctors of CT examinations in order to optimize their use.

[Percutaneous sacroplasty]. / La sacroplastie percutanée.

Sacral insufficiency fracture is a debilitating injury for which no active treatment is currently available. It frequently causes significant pain and limits activities of daily living in patients with osteoporosis. Percutaneous vertebroplasty is a common procedure to alleviate the pain associated with thoracic and lumbar vertebral compression fractures. The sacral percutaneous cimentoplasty procedure (sacroplasty) has recently been introduced as an alternative to medical management of osteoporotic sacral insufficiency fractures. The purpose of this article is to illustrate the effectiveness and the utility of percutaneous sacroplasty in this kind of pathology and to show how this procedure can provide symptom relief without having major complications.

[Patient dose optimization in pediatric computerized tomography]. / Optimisation des doses en tomographie computérisée pédiatrique.

The development of CT applications might become a public health problem if no effort is made on the justification and the optimisation of the examinations. This paper presents some hints to assure that the risk-benefit compromise remains in favour of the patient, especially when one deals with the examinations of young patients. In this context a particular attention has to be made on the justification of the examination. When performing the acquisition one needs to optimise the extension of the volume investigated together with the number of acquisition sequences used. Finally, the use of automatic exposure systems, now available on all the units, and the use of the Diagnostic Reference Levels (DRL) should allow help radiologists to control the exposure of their patients.

[CT-enteroclysis]. / CT-entéroclyse.

Computed tomography enteroclysis (CTE) has become a well-defined imaging modality for the evaluation of various small bowel disorders. The large volume (2 l) of enteral contrast agent administrated via a nasojejunal catheter ensures small bowel distension. Following helical CT acquisition is completed by multiplanar views. CTE is of particular value in intermediate or advanced Crohn's disease. It has become the method of choice for small bowel tumours. The cause and degree of low-grade small bowel obstruction is more readily analyzed with the technique of CTE than conventional CT. CTE should be selectively used to answer specific questions of the small bowel. It essentially contributes to the diagnostic quality of modern small bowel imaging, and therefore deserves an established, well-defined place among the other available techniques.

[Undifferentiated sarcoma of the liver: a rare tumor of childhood]. / Le sarcome indifférencié du foie: une tumeur rare chez l'enfant.

UNLABELLED: Undifferentiated sarcoma of the liver is a rare primary tumor of childhood: only about 150 cases have been reported in the literature. CASE-REPORT: A 10 year-old girl was admitted because of diarrhea and weight loss. Sonography, then CT-scan and MRI showed a large tumor of the liver. COMMENTS: In the differential diagnosis of primary liver tumors in children, one should think about undifferentiated sarcoma of the liver, especially if imaging shows haemorrhagic foci and if sonography and CT/MRI display a discordant appearance. Survival has improved in the last decade due to agressive surgery and intensive chemotherapy.

[Non invasive multidetector CT angiography of coronary arteries: when and how should I do?]. / Angiographie non invasive des coronaires en scanner multibarrette: comment, quand et pour qui?

Recent advances in multi-detector computed tomography technology offer a reliable tool for coronary arteries visualization and atherosclerotic plaque assessment. The objective of this article is to describe the principle of coronary angiography using multi-detector computed tomography, review the current diagnostic performances and help the reader to understand current applications and future challenges of multi-detector computed tomography in coronary artery disease diagnosis and management.

[Osteoid osteoma and radiofrequency]. / Thermoablation par radiofréquence de l'ostéome ostéoïde.

Osteoid osteoma and radiofrequency Osteoid osteoma relates to a benign skeletal neoplasm, smaller than 2 cm in diameter, composed of osteoid, highly vascularized connective tissue and surrounded by a ring of bone sclerosis. Its aetiology remains unknown. It affects twice more males than female patients and occurs usually between 5 and 40 years old. Long bones and spine are the most involved areas but the whole skeleton can be involved. Clinical manifestations can include local pain (increased at night and decreased by activity) and relief with salicylates administration. CT guided radiofrequency ablation of osteoid osteoma is in comparison to surgery less invasive, time saving and economic technique with excellent long term results.

[Percutaneous vertebroplasty]. / Vertébroplastie par voie percutanée.

Although vertebroplasty was initially a treatment of vertebral haemangioma or metastases, this procedure is now frequent option to the treatment of osteoporotic vertebral fractures. In this review article, we will discuss the indication, the techniques and the follow-up of the vertebroplasty. This is a risky procedure, which should be performed by experimented physicians working with high-resolution fluoroscopic equipments, by biplane fluoroscopy, to reduce the risk and irradiation to the patient. According to the available follow-up studies, there is clear evidence of a strong improvement of quality of life after vertebroplasty by rapid decreasing of back pain at least during the first six months. Other new studies will analyze the long-term follow-up after vertebroplasty.

Comparison of admission perfusion computed tomography and qualitative diffusion- and perfusion-weighted magnetic resonance imaging in acute stroke patients.

BACKGROUND AND PURPOSE: Besides classic criteria, cerebral perfusion imaging could improve patient selection for thrombolytic therapy. The purpose of this study was to compare quantitative perfusion CT imaging and qualitative diffusion- and perfusion-weighted MRI (DWI and PWI) in acute stroke patients at the time of their emergency evaluation. METHODS: Thirteen acute stroke patients underwent perfusion CT and DWI or PWI on admission. The size of infarct and ischemic lesion (infarct plus penumbra) on the admission perfusion CT was compared with that of the MR abnormalities as shown on the DWI trace and on the relative cerebral blood volume, cerebral blood flow, time to peak, and mean transit time maps calculated from PWI studies. RESULTS: The most significant correlation was found between infarct size on the admission perfusion CT and abnormality size on the admission DWI map (r=0.968, P<0.001). A significant correlation was also observed between the size of the ischemic lesion (infarct plus penumbra) on the admission perfusion CT and the abnormality size on the mean transit time map calculated from admission PWI (r=0.946, P<0.001). Information about cerebral infarct and total ischemia (infarct plus penumbra) carried by both imaging techniques was similar, with slopes of 0.913 and 0.905, respectively. CONCLUSIONS: An imaging technique may be helpful in the identification of cerebral penumbra in acute stroke patients and thus in the selection of patients for thrombolytic therapy. Perfusion CT and DWI/PWI are equivalent in this task.

Bone densitometry of the forearm: comparison of single-photon and dual-energy X-ray absorptiometry.

Forearm bone mineral densitometry was performed initially by single-photon absorptiometry (SPA), but is now achievable by dual-energy X-ray absorptiometry (DXA) as well, with a good correlation between both measurements. However, it is still unknown whether: (1) short-term precision of DXA is superior to SPA and (2) identical regions of interest (ROI) are mandatory to correlate SPA with DXA. The aim of this study was to answer these questions using a commercial system for DXA (DXA-FAS) and to test an in-house system using spine DXA and a soft-tissue compensator (DXA-STC). In ten subjects, four measurements on the same day showed significantly lower (p < 0.05) coefficients of variation (CV) for bone mineral density (BMD) by DXA-FAS (proximal site: 0.74%; ultradistal site: 1.20%) than by SPA (1.26% and 2.25%). However, the CV for bone mineral content (BMC) were similar for DXA-FAS (0.73% and 1.58%) and SPA (0.79% and 1.34%). The significant difference (p < 0.05) for surface calculation by DXA-FAS (1.24% and 0.93%) compared with SPA (2.36% and 1.28%) explains all the advantages of DXA-FAS for short-term precision. The measurements taken on the same day on the ulna and the radius or on the radius alone by SPA, DXA-FAS, and DXA-STC on 108 subjects aged 18-80 years were highly correlated [r ranging from 0.925 to 0.995 (p < 0.0001) and standard error of the estimate from 3.15% to 8.89%]. The need for a manual adjustment of the ROI was found to be mandatory for BMC but not BMD assessment. The use of DXA-STC is a fast method for forearm bone densitometry and its correlation with SPA is very high. However, its short-term precision for BMC (3.00% and 1.54%), BMD (2.15% and 1.12%), and surfaces (1.99% and 1.12%) is significantly higher (p < 0.05) than that of DXA-FAS. We conclude that short-term precision of DXA is better than that of SPA only for BMD and surface measurement but not for BMC. ROI should be adjusted manually for the assessment of BMC but not for that of BMD.

The Macklin effect: a frequent etiology for pneumomediastinum in severe blunt chest trauma.

STUDY OBJECTIVES: To review the etiology and pathophysiology of pneumomediastinum in severe blunt trauma, with a special interest in one of its possible origins, the Macklin effect. The Macklin effect relates to a three-step pathophysiologic process: blunt traumatic alveolar ruptures, air dissection along bronchovascular sheaths, and spreading of this blunt pulmonary interstitial emphysema into the mediastinum. The clinical relevance of the Macklin effect was also evaluated. SETTING: A university hospital serving as a reference trauma center. PATIENTS: A selection of 51 patients with severe blunt trauma between 1995 and 2000. INCLUSION CRITERIA: Severe trauma or high-speed deceleration justifying chest CT; if chest CT demonstrated a pneumomediastinum, bronchoscopy and esophagoscopy were performed to rule out tracheobronchial or esophageal injury. DESIGN: Retrospective analysis of patients' clinical files, chest CT, and bronchoscopy and esophagoscopy reports. The Macklin effect was diagnosed when an air collection adjacent to a bronchus and a pulmonary vessel could be clearly identified on the chest CT. Clinical relevance of the Macklin effect was statistically evaluated regarding its repercussions on the pulmonary gas exchange function, the respective durations of intensive care and total hospital stay, and the associated injuries. RESULTS: Twenty (39%) Macklin effects and 5 tracheobronchial injuries (10%) were identified. One tracheobronchial injury occurred simultaneously with the Macklin effect. The presence of the Macklin effect affected neither the clinical profile nor the result of pulmonary gas analysis on hospital admission, but was associated with a significant (p < 0.001) lengthening of the intensive care stay. CONCLUSIONS: The Macklin effect is present in 39% of severe blunt traumatic pneumomediastinum detected by CT. Its identification does not rule out a tracheobronchial injury. The Macklin effect reflects severe trauma, since it is associated with significantly prolonged intensive care stay.

Lemierre's syndrome in children: high-resolution CT and color Doppler sonography patterns.

Lemierre's syndrome is an anaerobic sepsis occurring after oropharyngeal infection in healthy teenagers and young adults. We report two cases of adolescent girls suffering from Lemierre's syndrome studied with cervical color Doppler ultrasonography (CDUS), cervicothoracic helical CT, and high-resolution CT (HRCT) scanning. In both patients, HRCT allowed a good depiction of multiple cavitated pulmonary nodules of various sizes suggestive of this entity and was able to detect small or peripheral nodules. CDUS helped to pinpoint the extent of thromboses of the internal jugular vein demonstrated by CT. CDUS and HRCT should be performed as early as possible to confirm and treat this life-threatening condition.