Biomedical subjects

W A Kaiser

Publications and source records attributed to W A Kaiser.

At least 37 records · Page 2Linked to original sources

PubMed2004

Palliative portal vein stent placement for lymphatic recurrence of gastric cancer.

INTRODUCTION: Percutaneous transhepatic stenting of the main portal vein is a rare intervention. CASE REPORT: In the current patient, percutaneous angioplasty and stenting of a main portal vein stenosis due to lymphatic recurrence of gastric cancer ameliorated the progressing therapeutic restriction. The wall stent achieved portal venous patency that enabled ongoing chemotherapy. The stent remained patent for the entire subsequent survival period.

Adult↗

PubMed2004

Comparison of whole-body STIR-MRI and 99mTc-methylene-diphosphonate scintigraphy in children with suspected multifocal bone lesions.

The study was performed to compare whole-body short time inversion recovery (STIR) MR imaging and (99m)Tc-methylene diphosphonate planar scintigraphy in the examination of children with suspected multifocal skeletal malignant lesions. Sixteen patients with known or suspected malignant skeletal disease underwent both whole-body STIR MR imaging and bone scintigraphy. The lesions were described and numbered according to scintigraphic evaluation criteria. Thus, 16 regions were analyzed in each patient for the comparison between the two modalities. Histology was proven in the primary malignant regions. Follow-up MRIs were registered. Scintigraphy and MRI follow-up were evaluated as gold standard. A total of 139 different lesions was observed by both modalities. Baseline whole-body MRI revealed 119 bone lesions in 256 possible sites (46.5%); scintigraphy revealed only 58 lesions (22.6%). Congruence was observed in only four patients (25%). According to the location of the lesion, correlation was observed in 39/139 lesions (28%). In all, 57.5% of the lesions were detected only by MRI and 14.5% of the lesions were detected only by scintigraphy. Whole-body MRI was more sensitive (P<0.001). Of all lesions numbered which could be separated in the initial MRI, whole-body MRI detected 178 lesions in the patients. The results suggest that whole-body MRI using a STIR sequence is an effective radiation free method for examination of children with suspected multifocal bone lesions. MRI showed more lesions than conventional (99m)Tc-methylene diphosphonate scintigraphy. Therefore, whole-body MRI may be feasible as a screening modality for metastatic and skip lesions in osteosarcoma, PNET, Ewing sarcoma and Langerhans cell histiocytosis in children.

Adolescent↗

PubMed2004

Simultaneous surface electromyography (SEMG) and 31P-MR spectroscopy measurements of the lumbar back muscle during isometric exercise.

The aim of this study was to demonstrate the feasibility of simultaneous surface electromyography (SEMG) and 31P-MR spectroscopy (31P-MRS) measurements on the back muscle of volunteers during the performance of an isometric exercise. Six volunteers (three male, three female) performed a modified Biering-Sörensen test inside a 1.5 T MR scanner while simultaneously recording SEMG signals. A surface coil was used for 31P-MRS with a CSI sequence. Spectra were collected with a voxel resolution of 40 mm x 40 mm x 100 mm and a temporal resolution of 30 s during periods of rest, sustained muscle contraction and recovery. The duration of muscle contraction was 150 s. SEMG analysis yielded a decrease of the mean SEMG frequency of approximately 20%. The SEMG amplitudes were constant or increased up to approximately 150% during exercise. 31P-MRS showed a maximum decrease of the phosphocreatine (PCr) amplitude down to approximately 32% of its initial value. Simultaneously, a doubling of the inorganic phosphate (Pi) signal was observed. The present study demonstrates that simultaneous SEMG and 31P-MRS measurements of the back muscle are feasible during isometric exercises.

Adult↗

PubMed2004

[Visualization of symmetric striopallidodentate calcinosis by using high-resolution susceptibility-weighted MR imaging. An account of the impact of different diagnostic methods of M. Fahr].

Bilateral striopallidodentate calcinosis, also known as Fahr's disease, is characterized by symmetric calcifications of the basal ganglia, thalami, dentate nuclei of the cerebellum and white matter of the cerebral hemispheres. Besides the common idiopathic etiology of bilateral intracerebral calcinosis, alterations of calcium metabolism are present in rare cases, which are especially caused by hormonal dysfunction of the parathyroids. Advanced imaging techniques, such as CT and MRI, demonstrate increasing relevance regarding diagnosis of bilateral striopallidodentate calcinosis. Intracranial calcifications are routinely observed with high sensitivity by CT. On MR images calcifications exhibit different signal intensities, which depend on the stage of the disease, differences in calcium metabolism and the compound of these calcifications. Application of a new high-resolution, susceptibility-weighted MR sequence allows detailed visualization of the intracerebral calcifications in Fahr's disease. Further diagnostic methods and important aspects regarding clinical manifestation of bilateral striopallidodentate calcinosis are also discussed.

Basal Ganglia Diseases↗

PubMed2004

[Clinical trial for differentiation between corticoid-induced osteoporosis and periarticular demineralization via digital radiogrammetry in patients suffering from rheumatoid arthritis].

PURPOSE: To investigate a new bone densitometric technology based on digital radiogrammetry (DXR) with respect to its ability to measure severity-dependent variations of bone mineral density (BMD) in patients with rheumatoid arthritis and to differentiate between corticoid-induced and periarticular bone mineral density loss. PATIENTS AND METHODS: A total of 153 randomly selected patients suffering from verified rheumatoid arthritis underwent digitally performed plain radiographs of the non-dominant hand and also measurements of dual-energy X-ray absorptiometry (DXA) regarding total femur and lumbar spine in 102 patients and peripheral quantitative computed tomography (pQCT) regarding the distal radius in 51 patients. Using DXR the radiographs of the non-dominant hand were analyzed for cortical bone mineral density calculation. The severity was classified in the DXA group using the Ratingen score. Furthermore, both study populations were divided into patients with and without corticoid therapy. RESULTS: Correlations between BMD determined by DXR and by DXA (R=0.44 for lumbar spine and R=0.61 for total femur) versus pQCT (0.46<R<0.59) were all significant. An appropriate association was confirmed between pQCT and DXA (R=0.61 for total femur and 0.73 for LWS). In the subgroup of patients with corticoid therapy (mean dose: 5 mg/d for a period of more than 6 month), our data showed-similar to the collective of all patients-significant correlations (0.34<R<0.59) between DXR and the other methods. In contrast to pQCT (0.37<R<0.59) the study revealed a poor association between DXR- and DXA-parameters in the subgroup of patients without corticoid therapy; only the correlation between DXA-BMD of total femur and DXR-BMD achieved a significant level (R=0.38, p<0.05). The mean value of BMD measured by DXR decreased severity dependently from 0.59 g/cm(2) (Stage 1) to 0.46 g/cm(2) (Stage 5). Similar results were verified for the metacarpal index (DXR). The relative decrease of BMD between the highest and lowest score was 21% (p<0.05). Otherwise the reduction of bone mineral density using DXA revealed no significant results. CONCLUSION: The DXR-based BMD calculation can distinguish severity and progress of disease-related periarticular demineralization in contrast to those of DXA. In this context, DXA primarily measures the systemic (corticoid-induced) osteoporosis and pQCT partially estimates disease-related bone mineral density loss, whereas DXR can predominantly analyze and quantify the periarticular demineralization, which often shows a manifestation at an early stage of rheumatoid arthritis. Therefore DXR seems to be a diagnostic tool in the course of rheumatoid arthritis.

Absorptiometry, Photon↗

PubMed2004

Dyslexia: the possible benefit of multimodal integration of fMRI- and EEG-data.

Biological research about dyslexia has been conducted using various neuroimaging methods like functional Magnetic Resonance Imaging (fMRI) or Electroencephalography (EEG). Since language functions are characterized by both distributed network activities and speed of processing within milliseconds, high temporal as well as high spatial resolution of activation profiles are of interest: "where" can dyslexia specific activations be detected and "when" do language processes start to diverge between dyslexics and controls? Due to the network character of language processing, fMRI-constrained distributed source models based on EEG-data were computed for multimodal data integration. First single-case results show that this method could be a promising approach for the understanding of a repeatedly described experimental finding for dyslexia like that of an overactivation in inferior frontal language areas. Multimodal data analysis for the subjects presented here could probably demonstrate that inferior frontal overactivations are the consequence of a phonological deficit and could represent ongoing articulation processes used to solve phonologically challenging tasks.

Adolescent↗

PubMed2004

[Lymphadenitits caused by nontuberculous mycobacteria].

Infections caused by nontuberculous mycobacteria (NTM) commonly manifest as lymphadenitis in otherwise healthy children, as pneumonia in patients with chronic airway diseases, and as disseminated disease in patients with immunosuppression. The aim of this case report is to describe imaging findings (sonography, electrical impedance scanning, MRI) in children with NTM infection of the head and neck and to give some information about microbiologic findings and therapeutic options. In children presenting with enlarged neck masses and radiologically demonstrated nodal masses, the diagnosis of infections with NTM should be considered.

Child, Preschool↗

PubMed2003

Conjoined lumbosacral nerve roots: current aspects of diagnosis.

Conjoined lumbosacral nerve roots (CLNR) are the most common anomalies involving the lumbar nerve structures which can be one of the origins of failed back syndromes. They can cause sciatica even without the presence of a additional compressive impingement (such as disc herniation, spondylolisthesis or lateral recess stenosis), and often congenital lumbosacral spine anomalies (such as bony defects) are present at the "conjoined sheaths". This congenital anomaly has been reported in 14% of cadaver studies, but myelographic or computed tomographic studies have revealed an incidence of approximately 4% only. Diagnostic methods such as magnetic resonance imaging (MRI) are helpful for determination of the exact anatomical relations in this context. We present five typical cases of conjoined nerve roots observed during a 1 year period, equivalent to 6% of our out-patients without a history of surgical treatment on the lumbar spine. In all cases with suspicious radiological findings MRI or lumbar myelography combined with CT and multiplanar reconstructions is recommended.

Adolescent↗

PubMed2003

Potential clinical relevance of digital radiogrammetry for quantification of periarticular bone demineralization in patients suffering from rheumatoid arthritis depending on severity and compared with DXA.

The aim of this study was to investigate a new bone densitometric technology based on digital radiogrammetry (DXR) with respect to its ability to measure severity-dependent variations of bone mineralization in patients with rheumatoid arthritis. One hundred six randomly selected patients suffering from verified rheumatoid arthritis underwent digitally performed plain radiographs of the non-dominant hand and measurements of dual-energy X-ray absorptiometry (DXA) regarding total femur and lumbar spine. Using DXR the radiographs were analyzed retrospectively for bone mineral density (BMD) calculation. The severity was classified using Larsen score and Steinbroker stage blinded by two radiologists. A third radiologist reviewed the incongruently scored cases. Mean values of calculated parameters changed as follows from Larsen 1 to Larsen 5: Bone mineral density (DXR-BMD) decreased from 0.55 to 0.44 g/cm2 (p=0.000), DXR-MCI decreased from 0.44 to 0.33 (p=0.001), DXA-BMD (total femur) decreased from 0.92 to 0.78 g/cm2 (p=0.090) and DXA-BMD (lumbar spine) decreased from 0.91 to 0.84 g/cm2 (p=0.595). Similar results were verified for the Steinbroker stage. The relative decrease of BMD measured by DXR between the highest and lowest score was 20% for Steinbroker stage and Larsen score (p<0.05). The relative decrease of BMD using DXA revealed not such a significant result. Similar results were verified for metacarpal index (estimated by DXR). Correlations between BMD determined by DXR and by DXA were all significant (R=0.45 for lumbar spine and R=0.59 for total femur). Consequently, less than 35% of the DXR-BMD value is explainable by corresponding DXA values. The DXR-based BMD calculation seems to be able to distinguish severity and progress of the disease in contrast to those of DXA at lumbar spine and total femur.

Absorptiometry, Photon↗

PubMed2003

Is the "blooming sign" a promising additional tool to determine malignancy in MR mammography?

The aim of this study was to evaluate potential diagnostic relevance of blooming effect for verification of suspicious breast lesions in MR mammography (MRM). The MRM examinations of 1035 patients, all following the same imaging protocol (from 1994 to 2001) were retrospectively evaluated by two experienced radiologists in consensus. A total of 817 lesions showed a focal enhancement; of these, 793 were histologically verified after surgical intervention so that 514 malignant and 279 benign lesions could be evaluated. Using a 1.5-T Gyroscan ACS II-imager (Philips, Hamburg, Germany) and a double breast coil with the patient lying in a prone position, 0.1 mmol/kgbw Magnevist (Schering, Berlin, Germany) were injected into the cubital vein to obtain dynamic axial and coronal T1-weighted fast-field-echo images every minute up to 7 min after bolus injection. Blooming sign describes a progradient unsharpness of lesion borders initially sharply shaped and fast enhancing 7 min after bolus injection; 324 of 514 (63.0%) malignant lesions and 41 of 279 (14.7%) benign lesions revealed a blooming sign (sensitivity 63.0%, specificity 85.3%, accuracy 70.9%, positive predictive value 88.8%, negative predictive value 56.0%). Forty-one of 279 benign lesions showed a blooming sign; of these, there were 4 of 86 (4.7%) fibroadenomas, 2 of 21 (9.5%) phylloides tumours, 11 of 38 (28.9%) papillomas, 3 of 9 (33.3%) radial scars, 2 of 19 (10.5%) mastitis, 1 of 4 (25%) galactophoritis, 1 of 3 (33.3%) ADH and 19 of 99 (17.2%) mastopathic proliferations, respectively. Blooming sign is a phenomenon which should be taken into account when diagnosing MR mammographies because it might increase the ability to discriminate uncertain breast lesions; however, this effect can only be used as an additional item to other well-known effects such as plateau, washout and cancer corner.

Adult↗

PubMed2003

Echoplanar diffusion-weighted MRI with intravenous gadolinium-DTPA.

It is occasionally necessary to repeat diffusion weighted imaging (DWI) after giving intravenous contrast medium (CM). However, the effects of CM on DWI and apparent diffusion coefficients (ADC) have not been fully examined. The aim of this prospective study was to investigate whether there are any diagnostically significant differences between echo-planar imaging (EPI)-DWI before and after intravenous CM. EPI-DWI was acquired twice in 203 consecutive patients before and after i.v. CM. Three blinded readers rated the diagnostic image quality. Quantitative ADC calculations were performed before and after CM in all 72 patients with lesions sufficiently large for quantification, and in 72 normal brain regions. Of the 203 patients, 127 had abnormalities on MRI, including ischaemic stroke (52), bleeding (nine), brain tumour with disturbed blood-brain barrier (BBB) (18) and other lesions (48). There were no significant signal differences on isotropic DWI before and after CM, even in lesions with definite disturbance of the BBB. No statistically significant difference between ADC of lesions and contralateral normal brain was observed.

Adult↗

PubMed2003

[31P-MR spectroscopy of the brain in patients with anorexia nervosa: characteristic differences in the spectra between patients and healthy control subjects].

PURPOSE: To investigate whether 31 P-MR spectroscopy can detect reduced concentrations of high-energy phosphates, like PCr and NTP, caused by decreased metabolic activity in the brain of patients with anorexia nervosa (AN) and, furthermore, whether any impairment of the cerebral membrane metabolism can be derived from the spectra. MATERIAL AND METHODS: 10 female patients, age range 12 - 20 years and mean BMI (body mass index) of 14.8 +/- 1.6 kg/m 2, with clinically diagnosed AN (ICD-10, F50.0) and 10 healthy control subjects, age range 12 - 21 years and mean BMI 19.0 +/- 2.1 kg/m 2, without nutritional disturbances: were investigated. 31P-MR spectroscopy was performed with a 1.5 T MRI unit using single volume selection in the frontal/prefrontal region of brain. Relative metabolic concentrations were quantified by normalizing the peak areas of the metabolites with the total area of the complete phosphorous spectrum, P tot, as well as with the peak area of beta-NTP. RESULTS: Significant differences between the two groups were observed for the metabolic ratios PDE/P tot, PDE/beta-NTP and alpha-NTP/P tot which were lower in the patient group except for alpha-NTP/P tot. These ratios also revealed a statistically significant correlation with the BMI (r PDE/Ptot = 0.747, r PDE/beta-NTP = 0.57, r alpha-NTP/Ptot = -0.56; p </= 0.1). Reduced relative concentrations of PCr/P tot, beta-NTP/P tot or Pi/P tot were not encountered. CONCLUSION: The lowered PDE/P tot ratio for patients with AN and its correlation with BMI suggests that decreased BMI induces compositional changes of the phospholipids in the brain, which decrease the fraction of mobile phospholipids.

Adolescent↗

PubMed2003

[Early results of ultrasound based calculation of broadband ultrasound attenuation and speed of sound in children and adolescents suffering from asthma].

PURPOSE: To determine broadband ultrasound attenuation (BUA) and speed of sound (SOS) on the os caicis in asthmatic children. To correlate these findings with sex, age, weight and height, topical steroid intake, and asthma severity grade (ASG). PATIENTS AND METHODS: 178 children (ASG 1 - 3)/(98 m, 80 f; mean age 11.9 +/- 3.1 y) were consecutively chosen from 4/00 to 9/01. Children with any other chronic disease were excluded. BUA and SOS were measured using SAHARA (Hologic lnc. Waltham, USA). Regional normative BUA and SOS data of 3 299 children (obtained with the same system), were used to calculate age-, weight- and height-matched standard-deviation-scores (SDS) for both sexes. Asthma severity grade and steroidal intake were determined. The highest topical steroid dosage was 500 micro g Fluticasone or 800 micro g Budesonide per day. RESULTS: 10/178 children were small and 7/178 tall per age (5.6 %/3.9 %), 11/178 children were light (6.2 %) and 9 heavy per age (5.0 %). 19 and 45 children had reduced BUA and SOS values, respectively. The following rates of reduced values were observed: girls: BUA 15.0 % (12/80), SOS 25.0 % (20/80); boys: BUA 7.1 %, SOS 25.5 % (7/98 and 25/98). Sexual differences were not significant. Reduced SOS-values were associated with higher severity and occurred significantly more frequent at children under steroidal intake (0.09 vs. 0.25 [BUA] and - 0.37 vs. - 0.07 [SOS]). CONCLUSION: Following our results an increase incidence of reduced speed of sound occurs in asthmatic children which is attributed to asthma severity and seems to be negatively influenced even by topically applied low dose steroids. This could be attributed to a steroid induced collagen synthesis deficiency followed by a reduced bone elasticity. Further studies, especially using a longitudinal study design are required to verify these findings.

Adolescent↗

PubMed2003

[Prospective analysis of quantification of contrast media enhanced power Doppler sonography of equivocal breast lesions].

PURPOSE: To evaluate the potential diagnostic value of quantification of contrast enhanced power Doppler sonography in breast lesions. MATERIALS AND METHODS: Before and after bolus application of 300 mg/ml of the contrast agent Levovist (Schering, Germany), 76 randomly selected equivocal breast lesions (37 benign, 39 malignant) underwent power Doppler sonography. The data were acquired with a 7.5 MHz linear array transducer (Sonoline Versa Pro and Sonoline Elegra Plus, Siemens, Germany). Following postprocessing digitalization, color pixel density (CPD) and dynamic contrast enhancement were calculated and compared using different regions of the tumor (entire lesion, center and periphery). RESULTS: A measurable pixel signal prior to the application of the contrast agent was observed in 12 of 37 benign and in 18 of 39 malignant lesions (32.4 % and 46.2 %, respectively). After administration of the contrast agent, the lesions with measurable signal increased to 20 of 37 (54 %) and 25 of 39 (64.1 %), respectively. No statistically significant difference of dignity-related signal intensity could be verified before or after administration of the contrast agent. Maximum CPD and relative increase in pixel density after contrast medium was appreciably higher in the center of malignant lesions than in corresponding regions of benign lesions. CONCLUSION: Quantification of color pixel density is rather nonspecific for the discrimination of equivocal breast lesions and not suitable for clinical routine. Signal detection and quantification of color coded pixels enable comparison of dynamic contrast enhancement.

Adult↗

PubMed2003

[Evaluation of the primary diagnosis with a CAD-system in mammography].

PURPOSE: To assess the capability of the computer assisted detection (CAD) system to classify calcifications that are histologically verified as malignant and benign or are proven benign by magnification and follow up mammography. MATERIALS AND METHODS: Three groups of microcalcifications (MC) with and without associated masses were enrolled in the study. The cancer group included 141 screen-detected breast cancer cases. One benign group comprised 109 cases with histologically benign specimens obtained through a minimally invasive breast biopsy. A second benign group included 72 lesions with MC that appeared benign on magnification/compression views and were confirmed to be benign on follow-up mammograms over a period of at least 1.5 years. All mammograms were evaluated with a CAD system (Second Look version 3.5, CADx Medical Systems, Canada). RESULTS: CAD correctly detected 125 of 141 (89 %) cancer cases. Of the 16 false negative cases, CAD marked the location of the MC (which were associated with malignant mass) with a mass mark in 12 cases. For benign cases, CAD did not correctly mark the microcalcifications in 59 of the 109 lesions confirmed benign histologically (54.1 %) and in 39 of the 72 lesions established benign mammographically (54.2 %). Adenosis introduced the highest rate of falsely marked microcalcifications (62 %). CONCLUSION: Due to its limited specificity, CAD can still not be recommended for the primary classification of microcalcifications as malignant or benign. Nevertheless, the low false negative rate and rather high detection rate of malignant findings indicate some value of CAD for an independent second reading.

Adenocarcinoma↗

PubMed2003

High grade and non-high grade ductal carcinoma in situ on dynamic MR mammography: characteristic findings for signal increase and morphological pattern of enhancement.

The objective of this review is to describe characteristic MR mammographic findings for signal increase and morphological patterns of enhancement in pure ductal carcinoma in situ (DCIS) and to differentiate between high grade and non-high grade lesions. The dynamic MR examination (1.5 T unit, contrast enhanced T(1) weighted two dimensional fast field echo, 96 ms repetition time, 5.0 ms echo time, 80 degrees flip angle) of 39 consecutive patients with pure DCIS was evaluated retrospectively. Categories were defined for signal increase (C1=normal, C2=slow, continuous, C3=strong initial and slow further increase, C4=strong initial increase followed by a plateau phenomenon, and C5=strong initial increase followed by a washout phenomenon) and morphological patterns (M0=no pattern observed, M1=linear or linear-branched, M2=segmental dotted or granular, M3=segmental homogeneous, and M4=focal spot-like). Time-intensity curves showing a C4 and C5 signal increase were considered suspicious for malignancy. All cases were correlated with histology. 62% of all tumours had a plateau or washout (C4, C5), 77% showed a strong initial signal increase (C3-C5). On evaluation of time-intensity curves alone MR mammography (MRM) findings were suspicious for malignancy in 62% of all DCIS cases. A segmental enhancement was found in 82% of all enhancing tumors and the M2 pattern in 73%. In a combined analysis of signal increase and morphology, 70% of non-high grade and 92% of high grade DCISs were correctly described as suspicious. The difference between non-high grade and high grade DCIS was not significant (p=0.148), while significant differences were found between G1 and G3 DCISs and between G1 and G2 DCISs (p<0.05). All G2 and G3 DCISs showed noticeable signal enhancement. The mean histological tumour size of non-high grade DCISs was smaller than that for high grade DCIS (p<0.05). The hallmark of DCIS on dynamic MRM was unilateral segmental enhancement, most commonly with a granular dotted morphology (M2). Hormone effects need to be considered as the main differential diagnosis. Signal enhancement kinetics similar to invasive carcinoma were seen in the majority of cases. A combined analysis of morphological pattern and signal enhancement considerably improved rate of detection. G2 and G3 DCISs were correctly diagnosed with a significantly higher rate of detection (92%) than G1 DCIS (53%) (p<0.05). Different average size of G1, G2 and G3 DCIS on pathology cannot be excluded as a reason for differences found. Normal MRM seems to exclude high grade DCIS.

Adult↗

PubMed2002

31P-MR spectroscopy in children and adolescents with a familial risk of schizophrenia.

Based on a previous report [9] on alterations of membrane phosphorus metabolism in asymptomatic family members of schizophrenic patients, the aim of the present study was to extend and improve the evaluation and data processing of (31)P spectroscopic data obtained from a larger study population by including an analysis of the broad spectral component (BC) of membrane phospholipids (PL). Eighteen children and siblings of patients with schizophrenia and a gender- and age-matched control group of 18 healthy subjects without familial schizophrenia were investigated with phosphorus magnetic resonance spectroscopy ((31)P-MRS) by using image selected in vivo spectroscopy (ISIS) in the dorsolateral prefrontal regions (DLPFR) of the brain. Spectral analysis was performed by using both the full and truncated FID to estimate metabolic peak ratios of different (31)P metabolites and the intensity and linewidth of the broad component. A significantly higher PDE level (p<0.01) and increased linewidth of the PDE components were observed for the high-risk group compared with the control group (p=0.02). No significant differences were observed for PME as well as for other (31)P-metabolites. No differences were observed between the left and right hemispheres for different normalised (31)P-metabolic levels. Decreased intensities (p=0.03) and smaller linewidths (p=0.01) were obtained for the broad component in the high-risk group. Impairments of membrane metabolism that are typical for schizophrenic patients are partially observed in adolescent asymptomatic family members of schizophrenics, including increased levels of low molecular PDE compounds indicating increased membrane degradation processes, no changes for PME, and decreased intensities and linewidths of the BC indicating changes in the composition and fluidity of membrane phospholipids. Despite limitations to completely suppress fast-relaxing components by dismissing initial FID data points, the spectroscopic results indicate additional changes in the membrane metabolism of high-risk subjects beyond changes of synthesis and degradation.

Adolescent↗

PubMed2002

Use of electrical impedance scanning in the differentiation of sonographically suspicious and highly suspicious lymph nodes of the head-neck region.

Sonographic differentiation between inflammatory and malignant lymph nodes is difficult, due in part to almost unchanged morphology of small lymph node metastases; however, as cancer cells exhibit altered dielectric properties, measurement of local electrical field distortions may be useful as adjunct to ultrasound in detection of malignancy. In this study, we evaluated the ability of electrical impedance scanning (EIS) to differentiate cervically located sonographically suspicious or highly suspicious lymph nodes. Seventy patients with 106 sonographically suspicious lymph nodes (mean size 20 x 13 x 13 mm, mean depth 8 mm) were examined using TransScan TS2000 (Siemens, Erlangen, Germany; manufactured by TransScan Research and Development Co., Israel). Included in the study were cervical ( n=64), inframandibular/periparotideal ( n=32) and nuchal/supraclavicular ( n=10) nodes. The EIS results were compared with histopathological ( n=100) and serological ( n=6) findings. Sixty-two of 64 malignant lymph nodes were correctly detected using EIS; 19 of 42 inflammatory/benign lymph nodes were correctly identified as benign (true positive 96.9%, true negative 45.2%; accuracy 71.3%, negative predictive value 90.5%, positive predictive value 59.6%). The high tumour detection rate achieved in this study suggests that EIS may be of value as an adjunctive technique in differentiation of lymph nodes of the head-neck region. Software changes to reduce the high number of false-positive markers are, however, necessary to improve the value in the evaluation during a regular clinical routine.

Carcinoma, Squamous Cell↗