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Biomedical subjects

Horst J Koch

Publications and source records attributed to Horst J Koch.

23 records · Page 2Linked to original sources
PubMed2002

Transcranial duplex sonography in the detection of patent foramen ovale.

PURPOSE: To determine the sensitivity of contrast material-enhanced transcranial color-coded sonography (c-TCCS) compared with that of contrast-enhanced transesophageal echocardiography (c-TEE) for detection of cardiac right-to-left shunt. MATERIALS AND METHODS: Forty consecutive patients with stroke or transient ischemic attack were admitted to the hospital and were examined by using c-TCCS and c-TEE. High-intensity transient signals (HITS) were counted for 25 seconds after the end of the Valsalva maneuver, and the numbers of HITS were classified in one of four categories (zero HITS, one to 10 HITS, >10 HITS without curtain, and curtain). A statistically significant difference was calculated with the Fisher exact test. RESULTS: HITS were counted in 21 (52%) patients by using c-TCCS and c-TEE. With both tests, no HITS were counted in 15 (38%) patients. In two (5%) patients, no HITS were counted with c-TEE but three HITS in one patient and five HITS in the other were counted with c-TCCS. In two (5%) patients, no HITS were counted with c-TCCS, but a small patent foramen ovale (PFO) was seen at c-TEE. With c-TCCS, the sensitivity was 91% (21 of 23) and the specificity was 88% (15 of 17). In 23 patients examined with c-TCCS, 14 (61%) patients had category 1 PFO; seven (30%) patients, category 2 PFO; and two (9%) patients, category 3 PFO. Mean HITS count in patients with category 1 PFO was 4.4 and that for those with category 2 PFO was 27.6. CONCLUSION: c-TCCS is a sensitive noninvasive method for detecting cardiac right-to-left shunt and is as sensitive as c-TEE.

Echocardiography, Transesophageal↗
PubMed2002

Observation on the integrity of the blood-brain barrier after microbubble destruction by diagnostic transcranial color-coded sonography.

OBJECTIVE: To investigate alteration of the blood-brain barrier from ultrasonic contrast agent destruction by diagnostic transcranial color-coded sonography using gadolinium-enhanced magnetic resonance imaging. METHODS: Healthy male volunteers received 10 mL (400 mg/dL) of Levovist (SH U 508A; Schering AG, Berlin, Germany; n = 6) or 3 mL of Optison (FS069; Mallinckrodt Inc, St Louis, MO; n = 4) followed by 0.3 mmol/kg magnetic resonance imaging contrast agent (Magnevist; Schering) intravenously. Then transcranial color-coded sonography was performed with a conventional color duplex sonographic system, which insonated the brain in a slightly angulated axial plane with temporal average intensity of less than 700 mW/cm2 or acoustic pressure amplitude of less than 2.69 MPa, attenuated by the temporal bone. Before, immediately after, and 2 hours after insonation, T1-weighted axial magnetic resonance imaging was performed. All magnetic resonance images were individually assessed, and T1 signal intensities were measured in 2 regions of interest in both hemispheres at the 3 time points. RESULTS: No focal contrast enhancement or damage to the brain and no significant difference between T1 signal intensities in the right and left brain regions could be detected during early or late phases when either ultrasonic contrast agent was used. CONCLUSIONS: This bioeffects study gives further evidence of the safety of ultrasonic destruction of Levovist and Optison microbubbles by diagnostic transcranial color-coded sonography. However, more subtle local effects may have been missed by gadolinium-enhanced magnetic resonance imaging. Studies on diagnostic contrast-enhanced transcranial color-coded sonography as well as microbubble-based drug delivery strategies should consider ultrasonic contrast agent microbubble characteristics and concentration as well as ultrasound transmission power levels.

Adult↗
PubMedDate not supplied

Correlation of Mini-Mental-State-Examination (MMSE), Syndrom-Kurztest (SKT) and Clock test (CT) scores in patients with cognitive impairment assessed by means of multiple regression and response surface analysis.

The objective of our study was to assess the correlation of routine neuropsychological test results in elderly patients referred to a gerontopsychiatric ward. MMSEs, CTs and SKTs were performed in 94 patients (age: median = 74 years, range = 54-89 years; 64 f, 30 m) with mild to moderate dementia and evaluated retrospectively. Pairwise Spearman rank correlation, multiple regression and response surface analysis were used to assess relations between test results. The scores of all three tests used were reciprocally correlated (P < 0.05) yielding the following pairwise R-values: SKT versus MMSE: -0.77, SKT versus CT: 0.69, MMSE versus Clock test: -0.61. Multiple regression analysis showed a maximum correlation of 0.87 and marked standardised beta values, if SKT was chosen as dependent variable. Test scores could be well fitted to both symmetric linear (SKT = a + b x CT + c x MMSE; R(2) = 0.67, P < 0.01) and non-linear (SKT = a + b x CT + c x MMSE + d x CT(2) + e x MMSE(2) + f x CT x MMSE; R(2) = 0.67, P < 0.01) response surfaces. In conclusion, test scores of SKT, CT or MMSE in patients with dementia showed a marked correlation. In clinical practice the may be considered as almost interchangeable test options.

Aged↗