Conventional two-dimensional (2-D) ultrasound is the standard method for the investigation of thyroid morphology. Volume calculations need model assumptions and are observer dependent. The present study performed with a commercially available three-dimensional (3-D) system Freescan added to a conventional ultrasound scanner compares the accuracy of conventional thyroid volumetry to several methods of 3-D volume determination. In vitro measurements were performed on thyroid phantoms with known volumes. The standard deviation of the normalized differences was 8.0% (3-D segmentation) and 10.5% (conventional). For the accuracy of volume determination in human thyroids we performed a postmortem study. The thyroid volume was calculated conventionally by the ellipsoid model and by two 3-D methods (segmentation and the newly developed multiplanar volume approximation). The reference volume was determined after resection by submersion. The standard deviation of the normalized differences was 26.9% for the conventional method, 9.7% for 3-D segmentation and 11.5% for the multiplanar volume approximation, showing significant better results for both 3-D methods and no significant difference between the 3-D methods. The 3-D system, therefore, achieves a better accuracy for thyroid volumetry than the conventional volumetry using planar images. In addition, the 3-D images are stored electronically and can be used for follow-up studies.

Since 1991 transcranial doppler sonography has been accepted in Germany as a technical confirmatory test for the assessment of a cerebral circulatory arrest in patients fulfilling the clinical criteria of brain death. This study correlated transcranial doppler findings to established scintigraphic methods such as planar scintigraphy, 99mTc-HMPAO SPECT and EEG patterns. 21 patients (15 males/6 females, mean age 15-69 yrs.) fulfilled all clinical criteria of brain death. They suffered from head injuries and spontaneous bleedings. All clinical and technical investigations were performed within 60-90 minutes. In 14/21 patients clinical findings and all confirmatory tests were consistent with brain death. Planar scintigraphy and SPECT gave completely corresponding results in all 21 patients. 7 patients showed not corresponding results. In two head-injured patients with skull defects TCD yielded an oscillating flow in the MCA but SPECT/planar scintigraphy gave a residual perfusion in the related brain areas. A corresponding residual EEG pattern was seen in one case. A patient with osteoclastic skull defect showed a collateral flow from the external carotid artery and another case a secondary reperfusion in depth of a regular expected MCA signal 12 hours after definitely verification of systolic spikes in the Circle of Willis. No cerebral perfusion was detectable in the scintigraphique techniques. In the three remainder with rest activity in EEG, TCD and radionuclide methods showed no intracranial perfusion. In the presence of open skull fractures, external liquor drainages and osteoclastic craniotomies oscillating flow in TCD does not constantly represent a cerebral circulatory arrest. Awaiting of systolic spikes is absolutely necessary, if no radionuclide method is available. Determination of brain death by TCD should be carried out by an experienced investigator since unexpected collateral flow signals can be misinterpreted.

Since 1991 transcranial doppler sonography has been accepted in Germany as a technical confirmatory test for the assessment of a cerebral circulatory arrest in patients fulfilling the clinical criteria of brain death. This study correlated transcranial doppler findings to established scintigraphic methods such as planar scintigraphy. Tc-99m-HMPAO SPECT and EEG patterns. 21 patients (15 males/6 females, mean age 15-69 yrs.) fulfilled all clinical criteria of brain death. They suffered from head injuries and spontaneous bleedings. All clinical and technical investigations were performed within 60-90 minutes. In 14/21 patients clinical findings and all confirmatory tests were consistent with brain death. Planar scintigraphy and SPECT gave completely corresponding results in all 21 patients. 7 patients showed not corresponding results. In two head-injured patients with skull defects TCD yielded an oscillating flow in the MCA but SPECT/planar scintigraphy gave a residual perfusion in the related brain areas. A corresponding residual EEG pattern was seen in one case. A patient with osteoclastic skull defect showed a collateral flow from the external carotid artery and another case a secondary reperfusion in depth of a regular expected MCA signal 12 hours after definetely verification of systolic spikes in the Circle of Willis. No cerebral perfusion was detectable in the scintigraphique techniques. In the three remainder with rest activity in EEG, TCD and radionuclide methods showed no intracranial perfusion. In the presence of open skull fractures, external liquor drainages and osteoclastic craniotomies oscillating flow in TCD does not constantly represent a cerebral circulatory arrest. Awaiting of systolic spikes is absolutely necessary, if no radionuclide method is available. Determination of brain death by TCD should be carried out by an experienced investigator since unexpected collateral flow signals can be misinterpreted.

We propose an automated method for the routine analysis of urinary iodide, using paired-ion reversed-phase HPLC with electrochemical detection and a silver working electrode. Assay conditions include a flow rate of 1.0 mL/min and an operating potential of 0.10 V. The retention time for iodide is 5.4 min. Sample preparation can be semiautomated by use of a reduced-pressure manifold. The detection threshold (signal-to-noise ratio of 3) was 2 pmol, corresponding to 0.04 mumol/L. The within-run precision (CV) for a pooled urine sample was 3.9% at 452 nmol/L iodide. The average recovery of added iodine was 94%. For comparison with a colorimetric method, we measured 177 random (untimed) urine samples by both HPLC (y) and a Technicon AutoAnalyzer acid digestion method (x). After removal of organically bound iodine, the results for unbound urinary iodide determined by the two methods were nearly identical (r = 0.99; y = -0.03 + 1.00x; Sy/x = 0.12 mumol/L). Comparison of total urinary iodine measured by the Technicon AutoAnalyzer with unbound urinary iodide determined by HPLC also showed a high correlation (r = 0.96; y = -0.03 + 0.78x; Sy/x = 0.23 mumol/L), because iodine is excreted in urine mainly as iodide. We conclude that iodine in urine can be accurately determined by the more convenient HPLC assay.

Hyperthyroidism induced by contrast agents in a major problem in patients with pre-existing thyroid disease, particularly in patients with functional thyroid autonomy. The present study was undertaken to evaluate whether contrast media applied during endoscopic retrograde cholangiopancreaticography (ERCP) may result in a significant increase of serum iodine levels and thus may be associated with the risk of iodine-induced hyperthyroidism. The courses of serum concentrations of total iodine and free iodide, as well as of urinary iodine excretion, were measured in 15 patients before and up to 21 days after ERCP. During ERCP, the non-ionic contrast medium iopamidol was instilled in amounts resulting in a total iodine load of 57.4 +/- 22.8 mmol (7.3 +/- 2.9 g). In all patients, ERCP resulted in a highly significant increase in serum levels of total iodine from 0.8 +/- 0.5 to 85.2 +/- 116.9 mumol/l 4 h after application of the contrast agent. In parallel, serum iodide levels were raised from 0.06 +/- 0.04 to 5.42 +/- 6.09 mumol/l and urinary iodine excretion from 71.1 +/- 35.7 mumol/mol creatinine to 621,620.9 +/- 636,492.2 mumol/mol creatinine. Peak concentrations of serum iodine are well related to the total amount of iodine applied (p < 0.05). During follow-up, iodine levels returned to pre-exposure levels within 2-3 weeks. Levels of thyrotropin, free thyroxine, and free triiodothyronine remained unchanged during the follow-up period. In conclusion, endoscopic application of iodinated contrast agents during ERCP leads to significant increases of serum levels of total iodine and free iodide and of urinary iodine excretion.(ABSTRACT TRUNCATED AT 250 WORDS)