Biomedical subjects

Hans-Joachim Mentzel

Publications and source records attributed to Hans-Joachim Mentzel.

25 records · Page 2Linked to original sources

PubMed2003

Normative values of bone parameters of children and adolescents using digital computer-assisted radiogrammetry (DXR).

PURPOSE: To verify whether estimation of bone mineral density (BMD) using digital X-ray radiogrammetry (DXR) is possible on children and to determine normative values of both such a DXR-BMD estimate and a corresponding metacarpal index (DXR-MCI) on. PATIENTS AND METHODS: In retrospect, X-rays were selected of the hands of 200 healthy Caucasian children (120 boys and 80 girls, aged 4-18 yr). The involved children were selected among a larger group of children submitted to the surgical department of our institute for evaluation of a suspected fracture after an occurred trauma. All children with a verified fracture or a chronic bone-related disease, including bone age retardation or acceleration, were excluded from the study. Furthermore, only conventional X-rays with the same film and capture parameters were included. The images were scanned and analyzed using the Pronosco X-posure system V.2 (Sectra Pronosco, Denmark). DXR-BMD, DXR-MCI, and a porosity index (DXR-PI) were automatically calculated using the midshafts of the metacarpals II-IV. Mean values of DXR-BMD and DXR-MCI were calculated separately for girls and boys in 2-yr intervals. RESULTS: In the present study the system has been demonstrated to be capable of calculating DXR-BMD from conventional X-rays of the hand from children down to approx 6 yr of age. This ability depended somewhat on the diameter and the length of the involved metacarpals. The success rate was higher for large bones than for small bones. The system succeeded in analyzing the images of 110 boys and 68 girls. Values of DXR-BMD were observed to increase with age from 0.40 g/cm2 to 0.62 g/cm2 in the male group and from 0.39 g/cm2 to 0.54 g/cm2 in the female group. Girls aged 11-12 yr had a higher DXR-BMD than did boys, corresponding to the earlier entry to puberty of girls. Standard deviations (SDs) reached values of up to 0.05 g/cm2. DXR-MCI increased with age from 0.36 to 0.47 for boys and from 0.34 to 0.49 for girls with a maximum SD of 0.06. The correlation between DXR-BMD and age was r=0.83 and r=0.84 for boys and girls, respectively. The corresponding correlations for DXR-MCI was lower, with observed correlations of r=0.63 (boys) and r=0.68 (girls), respectively, with p<0.01 in all cases. The DXR-PI did not reveal a significant correlation to age (r=-0.31 and r=0.04. respectively) and showed SDs marginally higher than the calculated mean values. CONCLUSION: The newly available DXR-methodology seems to offer the ability to determine DXR-BMD and DXR-MCI in children starting with a bone age of 6. This possibility may be of special relevance for children suffering from chronic bone diseases that require repeated X-rays of the hand (e.g. to determine bone age). The acquired normative data suggest that the measurements are of clinical value owing to low age-dependent variability (SDs) relative to an observed high increase with age. The clinical value of the porosity index (DXR-PI) remains uncertain and is limited owing to a high inter-individual variability.

Adolescent↗

PubMed2002

Radiological aspects of the Poland syndrome and implications for treatment: a case study and review.

UNLABELLED: Poland syndrome (PS) (OMIM 173800) is a rare congenital anomaly classically consisting of the combination of unilateral aplasia of the sternocostal head of the major pectoral muscle and an ipsilateral hypoplastic hand with simple syndactyly and short fingers. The aetiology is most probably a vascular disruption sequence of the subclavian arteries. In most cases, PS is sporadic. Familial occurrence suggests that genes exist which are involved in the pathogenesis as paradominant traits. The syndrome may include mammary hypoplasia and further muscle abnormalities which can be accurately defined by sonography and MRI. The evaluation of the vascular status can be performed using colour coded duplex sonography for peripheral arteries and contrast-enhanced MR-angiography for supra-aortic arteries. CONCLUSION: We report a 7-year-old girl with unilateral right sided Poland syndrome with particular emphasis on the radiological investigations of vascular abnormalities. A review of the literature concerning the origin, outcome, and implications for treatment is given.

Child↗

PubMed2002

Diffusion-weighted MRI of cholesteatomas of the petrous bone.

PURPOSE: To investigate if primary cholesteatomas of the petrous bone show high signal in diffusion-weighted imaging (DWI). MATERIALS AND METHODS: In this blinded study, we compared 15 patients with clinically certain cases and later surgically proven cholesteatomas vs. 12 patients with clinically acute otitis of the middle ear and 20 volunteers without petrous bone disease. Two blinded readers without knowledge of the clinical data decided in consensus agreement whether there was a pathologic signal increase in the petrous bone in an anisotropic single-shot echo-planar imaging (EPI) DWI sequence, an artifact, or no signal increase. RESULTS: Thirteen of 15 patients with cholesteatomas showed bright signal in EPI DWI, whereas 10 of 12 patients with acute otitis media and all volunteers presented the usual low signal of petrous bone. CONCLUSION: EPI DWI is a fast diagnostic method that may be an additional valuable tool in the workup of suspected cholesteatomas. The ability of this technique to differentiate between cholesteatomas and granulomas or chronic otitis is not yet available.

Artifacts↗

PubMed2002

US and MRI of gastrointestinal graft-versus-host disease.

Abdominal problems often complicate the clinical course after bone marrow transplantation. Graft-versus-host disease occurs as a complication of allogenic bone marrow transplantation. In this report, the findings of intestinal involvement are described and correlated with histopathological findings. Increased bowel-wall thickness and increased vascularity were shown by US. MRI demonstrated generalised increased bowel-wall thickness associated with bowel-wall enhancement after administration of i.v. gadolinium.

Bone Marrow Transplantation↗

PubMed2002

Voiding urosonography with ultrasonography contrast medium in children.

Voiding urosonography (VUS) with ultrasonography contrast medium is a new modality in the detection of vesicoureteral reflux (VUR) in children. The purpose of this study was to evaluate the diagnostic accuracy of VUS compared with voiding cystourethrography (VCUG) in the detection of VUR. One hundred and eighteen patients, aged 3 weeks to 16 years, with 234 ureterorenal units, were investigated by VUS with ultrasonography contrast medium and radiographic VCUG in one session. The indications were predominantly urinary tract infection and follow-up of previously detected VUR. During the sonographic examination, the bladder was filled with saline solution and an ultrasonography contrast medium (Levovist) was administered through a catheter. Reflux was diagnosed when echogenic bubbles were observed in the ureter or in the renal pelvis. Afterwards, conventional VCUG was performed. Concordant findings were obtained in 210 of 224 ureterorenal units (93.7%). Reflux was excluded by both methods in 174 units (77.7%). With the VCUG as the reference, the sensitivity of VUS was 90%, the specificity 94.6%, the positive predictive value 78.3%, and the negative predictive value 97.8%. The accuracy was 93.7%. In conclusion, VUS with ultrasonography contrast medium is a reliable diagnostic tool for the detection of VUR in children.

Adolescent↗

PubMedDate not supplied

Normative data for digital X-ray radiogrammetry from a female and male German cohort.

This study presents German reference data for digital X-ray radiogrammetry (DXR) differentiated by males as well as females, and quantifies for gender-specific and age-related differences including all DXR parameters. This study also documents the effects of different X-ray settings (e.g., radiographs of the wrist or the hand) on DXR measurements. There were 2085 patients who were prospectively enrolled (954 females and 1131 males) from a data pool of 11,915 patients with radiographs of the nondominant hand or wrist. All patients underwent measurements of bone mineral density (BMD), cortical thickness, bone width, and the metacarpal index (MCI) using DXR technology. These data showed a continuous age-related increase of the DXR parameters to the point of peak bone mass, then a continuous decline beyond the peak bone mass with accentuated age-related cortical bone loss in women. Peak bone mass is reached at approximately 30-34 yr for women and 45-49 yr for men. In addition, men had a significantly higher DXR BMD (mean: +12.8%) compared with woman in all age groups. Regarding the impact of various X-ray settings (e.g., X-ray(wrist) vs. X-ray(hand)), no significant difference was observed between both groups, men as well as women. The development of digital imaging technology has enabled more precise measurements of several radio-geometric features. The present study estimated normative reference values for DXR in German Caucasian women and men. Based on this reference data, a valid and reliable quantification of disease-related demineralization based on measurements of DXR BMD and MCI is now available for the Caucasian ethnic group.

Absorptiometry, Photon↗

PubMedDate not supplied

Cortical blindness after contrast-enhanced CT: complication in a patient with diabetes insipidus.

Transient cortical blindness is an uncommon but well-known complication following cerebral angiography. One possible cause of this complication is an adverse reaction to contrast agent, resulting in an osmotic disruption of the blood-brain barrier that seems to be selective for the occipital cortex. We report the case of a 16-year-old male patient with cortical blindness after intravenous application of nonionic contrast agent during CT angiography performed because of seizure that was attributed to thrombosis of the basilar artery on the basis of clinical findings. To our knowledge, the development of cortical blindness after CT angiography has not been described in the literature. The patient's symptoms were triggered by hyponatriemia and diabetes insipidus.

Adolescent↗