Search PubMed⌕ Search

Biomedical subjects

S Kern

Publications and source records attributed to S Kern.

At least 19 recordsLinked to original sources
PubMed2006

Altered distribution of leukocyte subsets and cytokine production in response to acute psychosocial stress in patients with psoriasis vulgaris.

Psoriasis (PSO) is a mainly T helper-type 1 (TH(1)) cell mediated chronic inflammatory skin disease characterized by epidermal hyperproliferation and psoriatic plaques. There is ample evidence that stress may trigger psoriatic eruption, however, the underlying mechanisms of stress-induced exacerbation of PSO are poorly understood. The specific goal of the present study was to investigate the impact of acute stress on pathologically relevant immune functions in PSO patients. PSO patients (n=23) and healthy controls (n=25) were exposed to a standardized laboratory stressor ("Trier Social Stress Test", TSST) including a free speech and mental arithmetics in front of an audience. Blood samples were collected 10min before and 1, 10, 20, and 60min after the TSST as well as 24h after the experiment at identical time points under resting conditions. Analyses of leukocyte subsets indicated a significantly increased number of leukocyte subpopulations (lymphocytes, granulocytes, CD3(+), CD8(+), CD16(+)/CD56(+), and CD3(+)/HLA-DR(+)) after the TSST (all p<.01) with no significant between-group differences. However, monocyte number (F(3,120)=2.7; p<.01) and number of CD4(+)cells (F(3,120)=3.09; p<.05) were found to be significantly higher in PSO sufferers than in controls. Moreover, a significant decrease of CD3(+)/CD25(+)cells was observed in the PSO, but not in the control group (F(3,120)=3.46; p<.05). After exposure to the TSST, stimulation of peripheral blood mononuclear cells (PBMCs) with phytohemagglutinin (PHA) resulted in elevated production of IFN-gamma (F(3,126)=6.9; p<.001) and IL-2 (F(3,123)=6.6; p<.001), and moreover, a decreased production of IL-10 (F(3,132)=5.22; p<.01) and IL-4 (F(3,129)=3.9; p<.01). No difference in stress-induced changes of cytokine production to PHA could be identified between the two experimental groups (all p>.05). The present findings suggest that acute psychosocial stress is associated with changes of immune functions known to be involved in PSO which may be one potential explanation of how stress may trigger psoriatic eruption.

Adrenocorticotropic Hormone↗
PubMed2005

Endocrine stress responses in TH1-mediated chronic inflammatory skin disease (psoriasis vulgaris)--do they parallel stress-induced endocrine changes in TH2-mediated inflammatory dermatoses (atopic dermatitis)?

In previous research we reported attenuated responsiveness of the hypothalamus-pituitary-adrenal (HPA) axis and further, an increased reactivity of the sympathetic adrenomedullary (SAM) system to stress in patients suffering from atopic dermatitis (AD). AD is a chronic inflammatory skin disease mainly triggered by TH(2)-dependent inflammatory processes. The specific goal of the present study was to investigate whether altered HPA axis and SAM system responsiveness to stress can also be found in TH(1)-mediated inflammatory conditions. Patients with psoriasis (PSO; n=23), a TH(1)-mediated inflammatory (autoimmune) skin disease and healthy controls (n=25) were exposed to a standardized laboratory stressor (TSST) which mainly consists of a free speech and a mental arithmetic task in front of an audience. To investigate HPA axis and SAM system responsiveness, cortisol, ACTH, and catecholamines were determined before and after the stress test. In addition, cortisol levels after awakening and cortisol levels during the day (short diurnal profile) were determined. In order to test feedback sensitivity of the HPA axis, a dexamethasone (DEX) suppression test (0.5 mg) was performed. Analysis of cortisol and ACTH levels after the stress test yielded no significant differences between PSO subjects and controls indicating no altered HPA axis function in this patient group. Further, no between-group differences were found in cortisol levels after awakening or during the day (short diurnal profile). Additionally, no difference between PSO and healthy subjects in the feedback sensitivity of the system could be found (DEX test). However, PSO patients showed elevated epinephrine (F(3,102)=4.7; p<0.005) and norepinephrine (F(3,135)=2.7; p<0.05) levels in response to the stress test when compared to the controls. These findings suggest no altered HPA axis responsiveness, but increased reactivity of the SAM system in TH(1)-mediated chronic inflammatory skin disease.

Adrenal Medulla↗
PubMed2005

Complete elastic tensor through the first-order transformation in U2Rh3Si5.

The complete elastic tensor of U(2)Rh(3)Si(5) has been determined over the temperature range of 5-300 K, including the dramatic first-order transition to an antiferromagnetic state at 25.5 K. Sharp upward steps in the elastic moduli as the temperature is decreased through the transition reveal the first-order nature of the phase change. In the antiferromagnetic state the temperature dependence of the elastic moduli scales with the square of the ordered moment on the uranium ion, demonstrating strong spin-lattice coupling. The temperature dependence of the moduli well above the transition indicates coupling of the ultrasonic waves to the crystal electric field levels of the uranium ion where the lowest state is a singlet. The elastic constant data suggest that the first-order phase change is magnetically driven by a bootstrap mechanism involving the ground state singlet and a magnetically active crystal electric field level.

Journal Article↗
PubMed2005

Variability of duration of action of neuromuscular-blocking drugs in elderly patients.

BACKGROUND: Steroid-based, non-depolarizing neuromuscular-blocking (NMB) drugs (e.g. rocuronium, vecuronium) are characterized by organ-dependent elimination and significantly longer durations of action in elderly compared to young patients. Cisatracurium is a benzylisoquinolinium NMB drug with a duration of action not altered by ageing. The objective of the study was to determine if elderly patients had less variability in duration of action with 2 x ED95 of cisatracurium compared to equipotent doses of rocuronium or vecuronium. METHODS: Informed consent was obtained from 66 elderly patients with normal renal and liver function. Preoperative midazolam (1 mg) was given IV. The anaesthestic induction was with 5 mg kg(-1) thiopental and 2 microg kg(-1) fentanyl. The patients received 0.6 mg kg(-1) rocuronium, 0.1 mg kg(-1) vecuronium or 0.1 mg kg(-1) cisatracurium. Anaesthetic maintenance was with sevoflurane in oxygen/nitrous oxide. Neuromuscular-blocking duration of action was defined as the return of T1 twitch height to 25% of control. Variability was determined by subtracting the actual duration of action from the mean duration of action for each drug. RESULTS: The durations of action (range, min) were: cisatracurium, 37-81; vecuronium, 35-137; and rocuronium, 33-119. The median of the variability of duration was significantly less with cisatracurium (7 min) compared to vecuronium (18 min) and rocuronium (18 min) (P < 0.05). CONCLUSION: When used with sevoflurane/N(2)O, there was a two-fold greater variability of duration of neuromuscular blockade in elderly patients receiving rocuronium or vecuronium compared with cisatracurium.

Aged↗
PubMed2002

Autologous concentrated platelet-rich plasma (cPRP) for local application in bone regeneration.

Platelets are rich in growth factors that may contribute to an accelerated tissue regeneration process. The therapeutic osteogenic effect of local platelet administration probably depends on the amount of growth factors delivered within. To improve platelet-derived factor preparations, the platelets have to be concentrated without loss of the granular growth factor load. An autologous procedure according to the Good Manufacture Practice (GMP) guidelines to prepare a high concentrate from platelet-rich plasma (cPRP) for clinical application in bone regeneration is presented. Platelet-rich plasma (PRP) was generated from the centrifugation supernatant of 250 ml anticoagulated autologous blood. The PRP was then further centrifuged at the day of operation to generate concentrated PRP (cPRP) in 8 ml plasma. The data from 34 patients (9 m, 25 f), ageing from 21 to 71 years (median 50.4) were evaluated. Both, the platelet counts as well as the TGF-beta1 concentrations in the cPRP were found to be 12-fold increased compared to the PRP values. Overall, a 17-fold increase in platelet concentrations was achieved compared to the patients' whole bloods and platelet counts correlated with increased levels of TGF-beta1 within the cPRP. These results give rise to quality control specifications for a safe and cost effective preparation of cPRP. The method has proven to be suitable for blood services to support the needs for treatment in oral and maxillofacial surgery.

Adult↗
PubMed2001

Efficacy and safety of thrombolytic therapy after initially unsuccessful cardiopulmonary resuscitation: a prospective clinical trial.

BACKGROUND: During cardiopulmonary resuscitation (CPR), thrombolysis can help to stabilise patients with pulmonary embolism and myocardial infarction. Moreover, thrombolysis during CPR has beneficial effects on cerebral reperfusion after cardiac arrest. We investigated this new therapeutic approach in patients in whom conventional CPR had been unsuccessful. METHODS: We assessed, in a prospective study, patients undergoing CPR after out-of-hospital cardiac arrest for cardiological reasons in whom return of spontaneous circulation was not achieved within 15 min. According to the Ustein criteria, our control group consisted of patients who were assessed during 1 year. After this year patients were treated with a bolus of 5000 U of heparin and 50mg, over 2 min, of tissue-type plasminogen activator (rt-PA treated group). This intervention was repeated if return of spontaneous circulation was not achieved within the following 30 min. For controls only CPR was given. FINDINGS: Overall, 90 patients were included; heparin and rt-PA were given to 40 patients. There were no bleeding complications related to the CPR procedures. Of the rt-PA group, 68% (27) had return of spontaneous circulation and 58% (23) were admitted to a cardiac intensive care unit, compared with 44% (22; p=0.026) and 30% (15; p=0.009) of the controls, respectively. At 24 h after cardiac arrest a larger proportion of the rt-PA group than of the controls was alive (35% [14] vs 22% [11], p=0.171), and 15% (six) of rt-PA-treated patients and 8% (four) of controls could be discharged from hospital. INTERPRETATION: After initially unsuccessful out-of-hospital CPR, thrombolytic therapy combined with heparin is safe and might improve patient outcome. On the basis of our data a randomised controlled trial might be regarded as ethical.

Aged↗
PubMed2001

Respiratory syncytial virus infection of the lower respiratory tract: radiological findings in 108 children.

For years the typical appearance of respiratory syncytial virus (RSV)-induced infection of the lower respiratory tract has been discussed. All available studies have led to different results. The aim of this study was to control these results, with 108 children. The age range was 1 day to 10 years (median 7 months). Within 72 h of admission, all children developed an RSV infection of the lower respiratory tract. Chest X-rays (pa-view) of 55 children under, and 53 children over, the age of 6 months (10/53>24 months) were evaluated. The diagnosis of RSV and the chest X-ray were mostly done on the same day. The major radiological findings of the two age-groups were compared by Wilcoxon's unpaired rank sum test. Major radiological findings were: normal chest X-ray (30%), central pneumonia (32%) or peribronchitis (26%). There was no statistical significance between the age-groups. Other findings were emphysema (11%), pleural effusion (6%), lobar- or broncho-pneumonia (each 6%), atelectasis (5%) or pneumothorax in one case. Therefore, the most common radiological findings in RSV-induced infection of the lower respiratory tract, supported by our results (RSV infection without bacterial superinfection) are central pneumonia, peribronchitis or normal chest X-ray. Thus an age-group separation into under or over 6 months is no longer necessary.

Bronchitis↗
PubMed2001

Nuclear localization of Dpc4 (Madh4, Smad4) in colorectal carcinomas and relation to mismatch repair/transforming growth factor-beta receptor defects.

The tumor-suppressor protein Dpc4 (Smad4, Madh4) regulates gene expression. On binding of an extracellular ligand of the extensive transforming growth factor (TGF) superfamily to its cognate receptor complex, latent cytoplasmic Dpc4 is activated and translocated into the nucleus to function as part of various DNA-binding transcriptional activator complexes. The most relevant ligand/receptor pair to control the tumor suppressive function of Dpc4 remains uncertain, but is usually assumed to be TGF-beta and its heteromeric receptor. We exploited a fortuitous experiment of nature to directly test this hypothesis: the TGF-beta type II receptor gene is inactivated by mutation in nearly all colorectal carcinomas having microsatellite instability, as seen in hereditary nonpolyposis colorectal cancer (HNPCC) and in sporadic medullary colorectal cancers. Using a specific and sensitive immunohistochemical label for Dpc4, we examined nuclear localization of Dpc4 in 13 HNPCC, six medullary, and 41 sporadic nonmedullary colorectal carcinomas. In agreement with published rates, two (5%) of 41 sporadic tumors showed complete loss of Dpc4 protein, indicative of genetic inactivation. All 13 HNPCC and six medullary tumors had intact cytoplasmic and nuclear Dpc4 localization. The TGFBR2 gene was sequenced in three of the cancers from patients with HNPCC, and all of these harbored inactivating mutations. The specificity of the immunohistochemical assay was demonstrated in xenograft tumors of syngeneic cell lines that differed in DPC4 genetic status because of an engineered gene knockout. Thus, nuclear localization of Dpc4 can be maintained in cells with inactivated TGF-beta type II receptors, suggesting the persistence of tumor-suppressive action of an upstream signaling input, most likely a ligand/receptor complex distinct from TGF-beta. Identification of the relevant input would be expected to have implications for the understanding of tumorigenesis and the design of rational biological therapy.

Animals↗
PubMed2001

Comparison of a continuous glucose-insulin-potassium infusion versus intermittent bolus application of insulin on perioperative glucose control and hormone status in insulin-treated type 2 diabetics.

STUDY OBJECTIVE: To compare the effect of two different perioperative insulin management regimes on patients undergoing either major surgery (vascular surgery) or minor surgery (vitrectomy). DESIGN: Prospective, double-blind randomized trial. PATIENTS: 48 insulin-treated type 2 diabetics aged 18 to 85 years were studied. SETTING: University medical center. INTERVENTIONS: Patients were divided into four groups of 12 patients each: Groups A and B (major surgery), Groups C and D (minor surgery). Group A and C patients were treated with a continuous modified glucose-insulin-potassium infusion according to blood glucose levels after intubation. Patients assigned to Groups B and D were treated with intermittent intravenous (IV) insulin injections when glucose levels exceeded 12 mmol L(-1). MEASUREMENTS: Glucose and potassium levels were measured every 15 minutes and 30 minutes during surgery and up to 4 hours post-surgery. Plasma levels of lactate, cortisol, glycerol, and free fatty acids were measured in arterial samples after intubation (S1), after extubation (S2), and 4 hours after surgery (S3). MAIN RESULTS: There were no significant differences of the patient characteristics among the four groups. There was no significant difference in the time course of plasma glucose levels and hormone variables measured among the four groups. One episode of hyperglycemia in Group D during the postoperative period was treated with 12 IV units of insulin. One patient in Group A and one in Group B received potassium intraoperatively (15 and 29 mmoL, respectively). Postoperatively, two other patients of Group A received 19 and 12,5 mmoL, respectively, and one of Group B received 20 mmoL potassium. CONCLUSIONS: Both regimens resulted in relatively stable and comparable blood glucose levels throughout the perioperative period of the minor and major surgeries without differences in metabolic control as measured by levels of lactate, cortisol, glycerol and free fatty acids. Simplicity would favor the intermittent regimen to manage insulin treated type 2 diabetics.

Adolescent↗
PubMed2001

Decline in offspring viability as a manifestation of aging in Drosophila melianogaster.

The evolutionary explanation of senescence proposes that selection against alleles with deleterious effects manifested only late in life is weak because most individuals die earlier for extrinsic reasons. This argument also applies to alleles whose deleterious effects are nongenetically transmitted from mother to progeny, that is, that affect the performance of progeny produced at late ages rather than of the aging individuals themselves. We studied the effect of maternal age on offspring viability (egg hatching success and larva-to-adult survival) in two sets of Drosophila melanogaster lines (HAM/LAM and YOUNG/OLD), originating from two long-term selection experiments. In each set, some lines (HAM and YOUNG, respectively) have been selected for early reproduction, whereas later reproduction was favored in their counterparts (LAM and OLD). In the HAM and LAM lines, both egg hatching success and larval viability declined with mother's age and did so with accelerating rates. The hatching success declined significantly faster with maternal age in HAM than in LAM lines, according to one of two statistical approaches used. Egg hatching success also declined with maternal age in YOUNG and OLD lines, with no difference between the selection regimes. However, the relationship between mother's age and offspring larva-to-adult viability differed significantly between these two selection regimes: a decline of larval viability with maternal age occurred in YOUNG lines but not in OLD lines. This suggests that the rate with which offspring viability declines with mother's age responded to selection for early versus late reproduction. We suggest broadening the evolutionary concept of senescence to include intrinsically caused declines in offspring quality with maternal age.

Aging↗
PubMed2001

Proteomic-based approach for the identification of tumor markers associated with hepatocellular carcinoma.

There is increasing evidence for an immune response to cancer in humans, demonstrated in part by the identification of autoantibodies to tumor antigens. The identification of panels of tumor antigens that elicit a humoral response may have utility in cancer screening, diagnosis or in establishing prognosis. Several approaches are currently available for the identification of tumor antigens. We have used a proteomic-based approach for the identification of tumor antigens that induce an antibody response which we have applied to hepatocellular carcinoma, a major type of cancer worldwide. Two-dimensional gel electrophoresis allows simultaneous separation of several thousand individual proteins from tumor tissue or tumor cell lines. Proteins eliciting a humoral response in HCC were identified by 2-D Western blotting using sera from patients with hepatocellular carcinoma, followed by mass spectrometry analysis and database search. The common occurrence of autoantibodies to specific proteins may have utility for HCC screening and diagnosis.

Antigens, Neoplasm↗
PubMed2001

The knee joint in early juvenile idiopathic arthritis. An ROC study for evaluating the diagnostic accuracy of contrast-enhanced MR imaging.

PURPOSE: Diagnosis of juvenile idiopathic arthritis (JIA) remains difficult due to unspecific clinical and laboratory findings, especially in early stages of the disease. The purpose of our study was to determine the sensitivity and specificity of MR imaging in diagnosing JIA of the knee joints. MATERIAL AND METHODS: Forty children (3-17 years old) clinically diagnosed with JIA (follow-up > 1 year) of a knee joint and a control group of 40 children with painful knee joints (MR diagnosis: bone bruise of the knee (n = 7), normal knee joint (n = 12), osteomyelitis (n = 6), septic arthritis (n = 2), bone tumor (n = 7) and miscellaneous bone lesions (n = 6)) were examined using a 1.5 T MR unit. T1-weighted spin-echo (SE), T2-weighted fast SE, contrast-enhanced T1-weighted SE and 2D gradient echo sequences were performed. The receiver operating characteristic (ROC) curves evaluation was conducted by 5 independent radiologists. RESULTS: The positive criteria for diagnosing JIA were joint effusions (n = 40), contrast-enhancing synovitis (n = 39), cartilage lesions (n = 15), subchondral erosions and bony destruction (n = 1). Sensitivity and specificity were 93.5% and 92.5%, respectively. Both cases of septic arthritis were misdiagnosed as JIA by all radiologists. CONCLUSION: Contrast-enhanced MR imaging seems to be a highly sensitive tool in establishing the diagnosis of JIA.

Adolescent↗
PubMed2000

Dysregulated expression of androgen-responsive and nonresponsive genes in the androgen-independent prostate cancer xenograft model CWR22-R1.

Treatment of metastatic prostate cancer with androgen-ablation often elicits dramatic tumor regressions, but the response is rarely complete, making clinical recurrence inevitable with time. To gain insight into therapy-related progression, changes in gene expression that occurred following androgen-deprivation of an androgen-dependent prostate tumor xenograft, CWR22, and the emergence of an androgen-independent tumor, CWR22-R, were monitored using microarray analysis. Androgen-deprivation resulted in growth arrest of CWR22 cells, as evidenced by decreased expression of genes encoding cell cycle components and basal cell metabolism, respiration and transcription, and the induced expression of putative negative regulatory genes that may act to sustain cells in a nonproliferative state. Evolution of androgen-independent growth and proliferation, represented by CWR22-R, was associated with a reentry into active cell cycle and the up-regulation of several genes that were expressed at low levels or absent in the androgen-dependent tumor. Androgen repletion to mice bearing androgen-independent CWR22-R tumors induced, augmented, or repressed the expression of a number of genes. Expression of two of these genes, the calcium-binding protein S100P and the FK-506-binding protein FKBP51, was decreased following androgen-deprivation, subsequently reexpressed in CWR22-R at levels comparable with CWR22, and elevated further upon treatment with androgens. The dysregulated behavior of these genes is analogous to other androgen-dependent genes, e.g., prostate-specific antigen and human kallikrein 2, which are commonly reexpressed in androgen-independent disease in the absence of androgens. Other androgen-responsive genes whose expression decreased during androgen-deprivation and whose expression remained decreased in CWR22 were also identified in CWR22-R. These results imply that evolution to androgen-independence is due, in part, to reactivation of the androgen-response pathway in the absence of androgens, but that this reactivation is probably incomplete.

Androgens↗
PubMed2000

Introduction. Time and medicine.

Although historians work with the record of events in public time, they have not developed an explicit understanding of lived time. To set the stage for the other essays in this issue of Annals, this introductory essay explores how an understanding of lived or "private" time began to emerge in the early 20th century in the works of that era's major thinkers: Henri Bergson's philosophy of duration, Emile Durkheim's social time, Sigmund Freud's five psychoanalytic temporal narratives, and Eugene Minkowski's exploration of lived time. This essay then considers the reaction against the burden of history that began with the great 19th-century historicizers: Comte, Hegel, Marx, Darwin, and Spencer. It reflects on the effort, beginning in those years, of modern artists and intellectuals to focus on the personal past in place of the overbearing burden of the historical past. New ways of experiencing the present, made possible by new communication technologies, including the telephone and telegraph, have centered on the experience of simultaneity. Norbert Wiener's cybernetics, Marshall McLuhan's globalism, and the Internet have further transformed how both the medical and lay communities experience past, present, and future, as well as near and far. The discussion concludes with consideration of Eurotransplant, an Internet-based information and action network used by physicians to coordinate organ transplantation; it is a system that integrates cybernetics, globalism, and the Internet in an everyday, real drama of the electronic age of simultaneity.

Cybernetics↗
PubMed2000

Appearance of autosomal recessive polycystic kidney disease in magnetic resonance imaging and RARE-MR-urography.

PURPOSE: To describe the appearance of autosomal recessive polycystic kidney disease (ARPKD) on MRI and RARE-MR urography. MATERIALS AND METHODS: Seven boys and one girl (aged 3 months to 14 years, median 2.5 years) were evaluated. Images were obtained with 0.23-T and 1.5-T MR systems using T1-weighted (T1-W) spin-echo, T2-weighted (T2-W) turbo-spin-echo and RARE-MR-urography sequences. Signal intensities, morphological appearance of the affected kidneys and, specifically, the picture of the urinary tract on RARE-MR-urography were evaluated. RESULTS: All children showed kidney enlargement, reniform but humpy kidney shape, homogeneously grainy renal parenchyma, normal renal pelvis and normal calyces. Signal intensity was hyperintense in T2-W images in all cases. In six cases (n = 7), T1-W images were hypointense. On RARE-MR urography a hyperintense, linear radial pattern was seen in the cortex and medulla which represents the characteristic microcystic dilatation of collecting ducts in ARPKD. Three boys and the girl presented with a few circumscribed small subcapsular cysts. CONCLUSIONS: In order to confirm the diagnosis of ARPKD, RARE-MR urography seems to be a non-invasive imaging tool that shows directly the microcystic dilated water-filled collecting ducts.

Adolescent↗
PubMed2000

Keratinase of Doratomyces microsporus.

The fungus Doratomyces microsporus produced an extracellular keratinase during submerged aerobic cultivation in a medium containing a protein inducer for enzyme synthesis. The keratinase was purified to homogeneity using hydrophobic interaction chromatography followed by gel chromatography. The molecular weight was estimated to be 33 kDa (from SDS-PAGE analysis) or 30 kDa (by gel chromatography), suggesting a monomeric structure. The isoelectric point of the enzyme was determined to be around 9. The optimal pH and temperature for keratinolytic activity were pH 8-9 and 50 degrees C, respectively. The serine protease inhibitor PMSF totally inhibited the keratinase. The enzyme was not glycosylated. It was capable of hydrolysing different keratinous materials as well as some non-keratinous proteins. Hydrolysis of some synthetic substrates, specific for known proteinases, suggested that the keratinase of D. microsporus is close to proteinase K.

Animals↗
PubMed2000

Differentiation of vascular birthmarks by MR imaging. An investigation of hemangiomas, venous and lymphatic malformations.

PURPOSE: To evaluate the use of MR imaging using standard sequences in the differentiation of common vascular birthmarks of soft tissues in childhood. MATERIAL AND METHODS: Forty-three lesions in 37 children (median age 33 months) with hemangiomas (n=25), venous (n=8) and lymphatic (n=10) malformations were retrospectively studied. Images were obtained with a 0.2 T and a 1.5 T MR unit, using T1-weighted spin-echo, T2-weighted turbo spin-echo and turbo STIR sequences. In addition, 19 contrast studies were evaluated. Signal intensities and morphological characteristics were analyzed. RESULTS: All hemangiomas were hyperintense in T2-weighted, and mostly (22/25) isointense compared to the surrounding skeletal muscle in T1-weighted images. The lesions were homogeneous or mildly inhomogeneous and well defined. Venous and lymphatic malformations showed similar patterns. Contrary to other lesions, no vessels or lobular architecture were detectable and contrast enhancement was absent in lymphatic malformations. CONCLUSION: A reliable differentiation between hemangiomas, venous and lymphatic malformations in childhood is not possible by standard MR sequences alone. Contrast media may be helpful as lymphatic malformations show no contrast enhancement. The main role of MR imaging is to determine the local extent or infiltration of deeper tissue layers and narrow the differential diagnosis of other soft tissue tumors.

Adolescent↗