Biomedical subjects

F Krummenauer

Publications and source records attributed to F Krummenauer.

At least 37 records · Page 2Linked to original sources

PubMed2001

Reproducibility of optical biometry using partial coherence interferometry : intraobserver and interobserver reliability.

PURPOSE: To evaluate the intraobserver and interobserver variability in axial length (AL), anterior chamber depth (ACD), and corneal radius measurements using an optical biometry instrument based on partial coherence interferometry (PCI). SETTING: Johannes Gutenberg University, Mainz, Germany. METHODS: In this observational case series and interobserver reliability trial, 30 healthy, emmetropic to moderately myopic eyes of 15 volunteers were evaluated. The AL, ACD, and corneal radius were measured 20 times in 10 eyes by 1 observer to evaluate the intraobserver variability. To evaluate the interobserver variability, the measurements were taken in 20 eyes by 5 different observers. Measurements were performed using the IOLMaster (Carl Zeiss) based on PCI. The data description is based on coefficients of variation and the statistical inference on reliability estimation based on analysis of variance. The main outcome measures were intraobserver and interobserver variability and reliability in AL, ACD, and corneal radii. RESULTS: The intraobserver variability (SD) was +/-25.6 microm for AL, +/-33.4 microm for ACD, and +/-12.9 microm for corneal radius. The coefficients of variation were 0.1%, 0.9%, and 0.17%, respectively. The interobserver variability (SD) was +/-21.5 microm for AL, +/-29.8 microm for ACD, and +/-15.9 microm for corneal radius. The coefficients of variation were 0.09%, 0.82%, and 0.21%, respectively. The reliability was 99.9% for AL, 97.8% for ACD, and 99.8%/99.5% for corneal radius (r1/r2). The slightly reduced reliability in ACD measurement was caused by a reduced intraobserver reliability of 1 of the 5 observers (R = 0.87). CONCLUSION: Partial coherence biometry using the IOLMaster for AL measurement was highly reliable, offering observer-independent measurement results.

Adult↗

PubMed2001

Reference values of fetal aortic flow velocity waveforms and associated intra-observer reliability in normal pregnancies.

OBJECTIVES: It was the aim of the present study to calculate new Doppler reference ranges for blood flow velocities (Vmax, Vmean, Vmin) and resistance indices (PI, RI) for the fetal descending aorta by automatic waveform analysis. DESIGN: Cross-sectional prospective study. SUBJECTS: Nine hundred and twenty-six low-risk pregnancies at 18-41 weeks' gestation. METHODS: Aortic blood flow velocities were derived with pulsed-wave color Doppler. Measurements were carried out at the level of the diaphragm. Reference ranges for the individual measuring parameters were constructed based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle. Further investigated were intra-observer reliability and the influence exerted by different measuring sites (aortic arch, diaphragm, below the renal vessels) on the aortic Doppler flow spectrum. RESULTS: Although a significant increase in aortic blood flow velocity was observed at 18-41 weeks' gestation (Vmax = 48.2 cm/s to 110.3 cm/s (P < 0.001), Vmean = 20 cm/s to 47.5 cm/s (P < 0.001) and Vmin = 7.6 cm/s to 18.6 cm/s (P < 0.001)), there were no significant changes in the pulsatility or resistance indices. The resistance indices PI and RI as well as absolute blood flow velocities (Vmax, Vmin) were significantly lower with increasing distance from the heart. Initial decreases were measured between the aortic arch and the diaphragm: PI, 2.34 to 1.87 (P < 0.0001); RI, 0.87 to 0.79 (P < 0.0001); Vmin: 8.5 cm/s to 15.0 cm/s (P < 0.0001). Furthermore, systolic blood flow velocities (Vmax) were decreased below the renal vessels from 97 cm/s to 64 cm/s (P < 0.0007). No significant changes were recorded in intensity-weighted mean flow velocities (Vmean). The intra-observer reliability was low, but of no clinical relevance. CONCLUSIONS: At constant measuring conditions, the reference ranges for blood flow velocities and resistance indices in the fetal aorta calculated by the authors serve as the basis for Doppler ultrasound antenatal examinations in a normal patient population and enable the early diagnosis of fetal risk.

Aorta, Thoracic↗

PubMed2001

Fecal elastase-1 determination: 'gold standard' of indirect pancreatic function tests?

BACKGROUND: Tubeless pancreatic function tests measuring the content of elastase-1 and the activity of chymotrypsin in stool are used with different cut-off levels and with varying success in diagnosing functional impairment of the pancreas. The aim of our study was to re-evaluate the sensitivity and specificity of elastase-1 and chymotrypsin in stool in the assessment of exocrine pancreatic insufficiency. METHODS: In 127 patients displaying clinical signs of malassimilation, the secretin-caerulein test ('gold standard'), fecal fat analysis, fecal chymotrypsin activity and fecal elastase-1 concentration were performed. Exocrine pancreatic insufficiency was graded, according to the results of the secretin-caerulein test, into mild, moderate and severe. Chymotrypsin and elastase-1 in stool were estimated using two commercially available test kits. Fecal elastase-1 concentration of 200 and 100 microg/g stool and chymotrypsin activity of 6 and 3 U/g stool were used separately as cut-off levels for calculation. RESULTS: 1) In 65 patients, a normal pancreatic function was found using the secretin-caerulein test. In 62 patients, an exocrine pancreatic insufficiency was found and classified into severe (n = 25), moderate (n = 14) and mild (n = 23). 2) The correlation between fecal elastase-1 and chymotrypsin with duodenal enzyme outputs of amylase, lipase, trypsin, chymotrypsin and elastase-1 ranged between 33% and 55% and 25% and 38%, respectively. 3) Using a cut-off of 200 microg elastase-1/g, stool sensitivities of fecal elastase-1 and fecal chymotrypsin (cut-off: 6 U/g) were 100% and 76%, respectively (P < 0.0001 and P < 0.001 respectively) in severe exocrine pancreatic insufficiency, 89% and 47% respectively (P < 0.001; P = 0.34, respectively) in moderate and 65% for both in mild pancreatic insufficiency. Specificities of elastase-1 and chymotrypsin in stool were 55% and 47%, respectively. 4) Elastase-1 based diagnostic provided a positive predictive value of 50% using a cut-off' 200 microg/g stool in a representative group of consecutively recruited patients with gastroenterological disorders. CONCLUSION: Determination of fecal elastase-1 is highly sensitive in the diagnosis of severe and moderate exocrine pancreatic insufficiency and is of significantly higher sensitivity than fecal chymotrypsin estimation. Specificity for both stool tests is low. Correlation between elastase-1 and chymotrypsin in stool and duodenal enzyme outputs is moderate. Neither test is suitable for screening, as they provide a pathologic result in roughly half of 'non-pancreas' patients.

Biomarkers↗

PubMed2001

Substantial reduction of platelet adhesion by heparin-coated stents.

Although optimized antiplatelet medication has improved the clinical outcome after coronary stenting, vessel occlusion and restenosis still remain a relevant clinical problem. Platelets play a key role in this process. Therefore, the authors compared the platelet adhesion on different stent surface modifications (electropolished without coating or coated with carbon, carbon and additional heparin, silicon carbide, or heparin alone) to investigate their role in reducing platelet adhesion. All stents and additional stainless steel plates were incubated in heparinized whole blood with radiolabeled platelets. After washing the stents and plates four times, radioactivity caused by the adhesion of radiolabeled platelets was measured. The adhesion of radiolabeled platelets, compared to uncoated, electropolished stents, was reduced through silicon carbide coating to 58.6%, by carbon coating with additional heparin to 32.9%, and heparin coating alone to 7.7%. Stent coating with heparin is the most effective among the examined coatings in reducing platelet adhesion in vitro.

Anticoagulants↗

PubMed2001

Lack of association between carotid artery volume blood flow and cardiac output.

OBJECTIVE: The correlation of cardiac output and cerebral perfusion is unclear. We tested this potential association by correlating cardiac output data obtained by echocardiography and cerebral blood flow data as determined by color M-mode measurements of carotid artery blood flow. METHODS: We studied 43 patients with a broad spectrum of cardiac performance by means of transthoracic echocardiography. In these patients, different cardiac indices such as stroke volume, ejection fraction, and heart minute volume were determined. The data were correlated with volumetric flow measurements (color M-mode duplex system) of the common carotid arteries bilaterally. RESULTS: Heart minute volume ranged from 1.632 to 9.836 mL/min (mean +/- SD, 4.652 +/- 1.621 mL/min); ejection fraction ranged from 18% to 76% (mean, 48% +/- 16%). The relative fraction of carotid volume flow compared with heart minute volume was 15% +/- 6%. There was no correlation between ejection fraction, stroke volume, or heart minute volume and absolute volume flow in the carotid arteries when being adjusted for age. There was a highly significant inverse correlation (r = -0.8; P < .0001) of the relative fraction of the carotid volume flow (carotid volume flow/heart minute volume [percent]) and the heart minute volume. CONCLUSION: Our data support the concept that cerebral blood flow is independent of cardiac output.

Cardiac Output↗

PubMed2000

[Evaluation of diagnostic scores via intercategorial kappa coefficients].

A study design for the evaluation and confirmed modification of diagnostic rules is described. Based on the assessment of intercategorial rater agreement, those categories, which cause confusion in multiple ratings, can be combined and the gain in rater agreement can be assessed by the computation of appropriately modified kappa measures. The proposal is illustrated by the analysis of an evaluation trial related to SPECT based classification of patients with Graves' ophthalmopathy.

Diagnostic Imaging↗

PubMed2000

Healon5 versus Viscoat during cataract surgery: intraocular pressure, laser flare and corneal changes.

BACKGROUND: The use of a viscoelastic substance facilitates cataract surgery. Healon 5 is a new viscoelastic product with special rheological properties. We evaluated the postoperative effect of Viscoat and Healon5 on intraocular pressure (IOP), central corneal thickness (CCT), endothelial cell counts and laser flare. METHODS: Forty-eight eyes of 48 patients undergoing routine phacoemulsification followed by foldable IOL implantation were enrolled. Either Healon5 or Viscoat was used according to a block-randomization scheme. The aspiration technique was standardized. IOP, CCT, endothelial cell counts and laser flare were compared pre- and postoperatively. Statistical analysis was performed using the two-sample Wilcoxon test. Data description was based on median and quartiles, while graphic description was performed by non-parametric box plots. RESULTS: Viscoat demonstrated a statistically significant higher IOP than Healon5 at 4 and 8 h postoperatively (P< 0.01 and < 0.05, respectively). Further, the laser flare values were statistically significantly higher for the Viscoat than for the Healon5 group 8 h postoperatively (P<0.05). Endothelial cell loss did not differ significantly between the two groups (relative change in endothelial cell density after 3 months: -4.3% for the Healon5 group and -6.2% for Viscoat group). CONCLUSION: There was neither a statistically nor a clinically significant difference in endothelial cell loss after the use of Healon5 or Viscoat in routine cataract surgery. However, the IOP in the early postoperative period was higher in the Viscoat group than in the Healon5 group.

Adult↗

PubMed2000

[Retrospective analysis of the prognostic significance of the manner of mandibular resection and adjuvant radiotherapy in para-mandibular carcinomas].

The prognostic effect of bone resection (continuous vs non-continuous) was analysed in a retrospective study of 100 patients who were treated for squamous cell carcinoma located close to the lower jaw, between 1983 and 1994. Tumour stage, type of bone resection, extent of lymphatic node resection, dose of radiotherapy and chemotherapy were documented. Prognosis was characterised by the statistical end points "death", "metastasis" and "relapse". Thirty-two stage pT2 carcinomas, half of which were treated by continuous and half by non-continuous resection of the lower jaw, showed the same occurrence of the statistical end points death, metastasis or relapse. There was a trend towards a significantly longer survival time and metastasis-free interval in the group of continuous resection. The hazard ratios, however, showed no effect depending on the type of resection. However, both tumour stage (pTNM) and dose of radiation independently influenced prognosis in multivariate analysis. Consequently, three groups were defined. Univariate analysis of 62 patients without radiotherapy vs 19 with low-dose radiotherapy (36 Gy) and 19 with high-dose (62 Gy) showed a positive effect on the rate and time of survival in the group treated with high-dose radiotherapy. This was confirmed by multivariate analysis showing significantly lower hazard ratios for death and metastasis in the high-dose radiotherapy group after adjusting to cofactors (e.g. tumour stage). The data of this study challenge the current concept of resection of the lower jaw. However, due to the low number of patients and the retrospective character of the study, it is not possible to give suggestions regarding established therapy concepts. The advances of a high-dose radiotherapy in this study should be the subject of further multicentre retrospective and prospective randomised trials.

Adult↗

PubMed2000

Inflammation after sclerocorneal versus clear corneal tunnel phacoemulsification.

OBJECTIVE: To compare the postoperative inflammation after phacoemulsification followed by intraocular lens (IOL) implantation by means of sclerocorneal versus clear corneal tunnel incision. DESIGN: Randomized controlled clinical trial. PARTICIPANTS: One hundred eyes of 100 patients were examined at a German University eye hospital. INTERVENTION: One hundred eyes with cataract necessitating phacoemulsification with posterior chamber IOL implantation were randomly assigned to receive a temporal sclerocorneal or clear corneal tunnel incision by a single surgeon. MAIN OUTCOME MEASURES: Preoperative and postoperative inflammation was evaluated by measurement of flare using laser flare photometry. Statistical inference was mainly based on nonparametric group comparisons by use of two sample Wilcoxon tests. RESULTS: Mean anterior chamber flare in the group with sclerocorneal tunnel increased from 7.5 photon counts/ms preoperatively to 19.6 at 6 hours postoperatively and decreased to 11.1 (day 1), 11.7 (day 2), 11.6 (day 3), and 9.2 (5 months) during the postoperative course. The mean flare in the clear corneal tunnel incision group increased from 7.7 preoperatively to 12.9 at 6 hours postoperatively and then decreased to 9.2 (day 1), 9.8 (day 2), 9.1 (day 3), and 9.2 (5 months). Individual postoperative flare changes were significantly lower in the clear corneal tunnel group at the day of surgery (P<0.0001), as well as at day 1 (P = 0.0011), day 2 (P = 0.0079), and day 3 (P = 0.0020). After 5 months, no statistically significant difference was found. CONCLUSIONS: After phacoemulsification and foldable IOL implantation, postoperative alteration in the blood-aqueous barrier was statistically significantly lower with the clear corneal tunnel incision group compared with the sclerocorneal incision group, in the first 3 days postoperatively.

Adult↗

PubMed2000

The biometrical comparison of cardiac imaging methods.

OBJECTIVES: Biometrical comparison procedures for cardiac imaging methods with continuous outcome are reviewed mainly concentrating on assessment and design adequate comparison of accuracy and precision. Univariate graphical and numerical representation of corresponding deviations is outlined to derive a 'check list' of minimum information necessary to compare the measurement methods. DATA: The methods reviewed here are illustrated by the comparison of standard 2DE bidimensional cardial volumetry versus assessment using TDE colour imaging in 28 normal probands. SOURCES: The paired t-test and the corresponding confidence interval approach are used to assess deviations in location of two imaging methods; the test procedures of Maloney and Rastogi Hahn and Nelson and Grubbs are surveyed as proposals for the comparison of precisions in paired data. The Krippendorff coefficient and the Bradley/Blackwood test are illustrated as surrogate measures for method concordance. CONCLUSIONS: Since these methods can be performed by simple modification of standard options available in most statistics software packages, this review intends to enable cardiologists to choose appropriate methods for statistical data analysis and representation on their own.

Biometry↗

PubMed2000

Effect of large positioning holes on capsule fixation of plate-haptic intraocular lenses.

PURPOSE: To compare the centration and fixation of silicone plate-haptic intraocular lenses (IOLs) with different-sized positioning holes. SETTING: Eye Clinic of the Johannes Gutenberg-University Mainz, Mainz, Germany. METHODS: In a prospective randomized study, 51 Chiroflex C10 and 56 Chiroflex C11 IOLs were implanted under standardized conditions by the same surgeon. The IOL position was documented at the end of surgery and by retroillumination on the first day and 5 months postoperatively. The positioning-hole area was evaluated by ultrasound biomicroscopy (50 MHz) 5 months postoperatively. RESULTS: One day postoperatively, no IOL in either group was decentered more than 1.0 mm. After 5 months, 33% of the C10 and 42% of the C11 IOLs were decentered between 0.5 and 1.0 mm, and 11% of the C10 and 8% of the C11 IOLs were decentered more than 1.0 mm (maximum 1.23 mm and 1.41 mm, respectively). Up to the first postoperative day, 20% of the C10 and 22% of the C11 lenses were rotated more than 15 degrees. At 5 months, an additional 15% of the C10 and 19% of the C11 lenses were rotated. Ultrasound biomicroscopy showed no tissue or capsule adhesion in the holes in most cases (85% C10 group; 71% C11 group). No difference was statistically significant. CONCLUSIONS: Larger positioning holes did not prevent IOL decentration or rotation; thus, this IOL design appears unsuitable for correcting astigmatism. Because tissue in the positioning hole was rare with both lens types, it is doubtful that enlarged plate-haptic perforations will prevent IOL luxation into the vitreous cavity after capsulotomy.

Aged↗

PubMed2000

Quantification of video-taped images in microcirculation research using inexpensive imaging software (Adobe Photoshop).

BACKGROUND: Study end-points in microcirculation research are usually video-taped images rather than numeric computer print-outs. Analysis of these video-taped images for the quantification of microcirculatory parameters usually requires computer-based image analysis systems. Most software programs for image analysis are custom-made, expensive, and limited in their applicability to selected parameters and study end-points. METHODS AND RESULT: We demonstrate herein that an inexpensive, commercially available computer software (Adobe Photoshop), run on a Macintosh G3 computer with inbuilt graphic capture board provides versatile, easy to use tools for the quantification of digitized video images. Using images obtained by intravital fluorescence microscopy from the pre- and postischemic muscle microcirculation in the skinfold chamber model in hamsters, Photoshop allows simple and rapid quantification (i) of microvessel diameters, (ii) of the functional capillary density and (iii) of postischemic leakage of FITC-labeled high molecular weight dextran from postcapillary venules. We present evidence of the technical accuracy of the software tools and of a high degree of interobserver reliability. CONCLUSION: Inexpensive commercially available imaging programs (i.e., Adobe Photoshop) provide versatile tools for image analysis with a wide range of potential applications in microcirculation research.

Animals↗

PubMed2000

Precision and accuracy of measurements in digital panoramic radiography.

OBJECTIVES: To evaluate the precision and accuracy of digital measurements in digital panoramic radiography. METHODS: A series of 70 digital panoramic radiographs were obtained of a dry skull in seven different positions with metallic pins and spheres fixed to the mandible. Three replicate measurements were performed with the mouse-driven cursor by one reader at 1:1 and 2:1 magnification. Precision was assessed with the reliability index (R) and Malony/Rastogi test and the effect of magnification on accuracy by paired Wilcoxon test. RESULTS: Vertical measurements were less reproducible than horizontal measurements. There were significant differences in assessments between images at 1:1 and 2:1 magnification (P < 0.05). The maximum variation in mean difference was 0.4% of actual object length for pins and 1.2% for spheres. The difference did not exceed 0.1 mm. R was lower for 2:1 magnification and consistently lower for spheres compared with pins. CONCLUSION: The most reliable measurements were obtained of linear objects in the horizontal plane. Digital measurements are sufficiently accurate for clinical use.

Data Display↗

PubMed2000

[Planning sample size in ophthalmologic studies].

An essential aspect in the cooperation of clinic and biometry consists in designing of studies, e.g. during the preparation of grant applications or for review by official drug surveillance institutions. A central aspect in study planning is the design-adequate and well-documented prediction of sample size, which should be recommended for any intended study. Based on several examples for sample size planning in study designs, which are of common relevance for ophthalmology, guidelines are derived to enable clinical researchers to perform sample size planning on their own. The latter can be based on the various available software packages for sample size prediction.

Bias↗

PubMed2000

[Does ultrasonographic-morphologic staging of lymph nodes in head and neck cancer lend itself to automation?].

OBJECTIVES: B-scan ultrasound imaging is an obligatory examination of great clinical relevance in patients with head and neck cancer. The procedure, however, is dependent on an experienced examiner and thus requires higher personal resources than other examination techniques. In addition, its subjective character leads to possible deficits in reliability and objectivity. Established sonomorphologic criteria (echo-contour, echo-density, echo-structure, boundary) should therefore be matched to the findings of computer aided sonomorphometry. METHOD: 200 sonographic images of the cervical region of patients with oral carcinoma were analysed semi- and fully automatically as well as interactively by standard image analysis software (Quantimed 500, Leica, Germany). The results were evaluated statistically and correlated to the findings of both an experienced and inexperienced examiner. RESULTS: Fully automatic image analysis was impossible, as the software did not correctly identify the lymph nodes without interactive support. Quality of the semiautomatic and interactive image analysis mainly depended on the correct manual identification of the boundaries of the lymph node. Regarding this criterion the image analysis software was not able to compensate for the deficits of an inexperienced examiner. CONCLUSION: Delegation of the sonographic analysis to inexperienced, less qualified personnel, even with the help of image analysis software, seems to be inadvisable. This is especially the case if three-dimensional information from the real time analysis is not available.

Automation↗

PubMed2000

[Contrast media-enhanced 3D MR angiography of peripheral arteries using an automatic tracking technique at 1.0 Tesla].

PURPOSE: Assessment of the value of contrast-enhanced MR angiography (ceMRA) using an automatic tracking technique at 1.0 Tesla in comparison with digital subtraction angiography (DSA) of the pelvic and lower limb arteries. MATERIALS AND METHODS: In 15 patients with peripheral arterial occlusive disease a ceMRA (3D FLASH, TR/TE = 6.2/2.3 ms, Flip angle alpha = 30 degrees, Matrix 170 x 256) using a new automatic tracking technique was accomplished. The reference method was DSA. Twenty-one vessel segments of each patient were graded as normal, stenosed (> 50%) or occluded. Image material was evaluated independently by two radiologists. RESULTS: In comparison, the interobserver agreement showed a good (Cohen's kappa > 71%) concordance for 38% of the 21 vessel segments, a moderate (Cohen's kappa between 31%-70%) for 21% and a poor (Cohen's kappa < 30%) concordance for 38% of the 21 vessel segments. Regarding the MRA and DSA results, a good concordance was achieved for 62% of the 21 vessel segments, 14% showed a moderate concordance and 24% only a poor concordance. CONCLUSION: In patients with peripheral arterial occlusive disease ceMRA using an automatic tracking technique enables a reliable evaluation of pelvis and upper limb arteries at 1.0 Tesla. However, a reliable evaluation of lower limb arteries is not yet possible.

Aged↗

PubMed2000

Somatostatin-receptor scintigraphy in Graves' disease: reproducibility and variance of orbital activity.

Somatostatin-receptor (SSTR) scintigraphy using the single photon emission computed tomography (SPECT) technique allows the assessment of orbital inflammation in patients with Graves' disease. Previous studies showed differences in orbital octreotide uptake already 4 hr after injection. In this study, analysis of inter-/intra-observer variance and reproducibility in the evaluation of orbital SPECT images was performed. First, SPECT data of one representative female patient with clinically active Graves' ophthalmopathy (GO), obtained 4 hr after intravenous injection of 110 MBq 111In-pentetreotide and processed by filtered backprojection, were analyzed. Transverse SPECT images were reconstructed, an optimal orbital image was selected and predetermined regions of interests (ROIs) for both orbits were positioned by three independent observers 15 to 19 times each. In a second step, SPECT data of 8 different patients with GO were evaluated in the same manner by four independent observers 3 to 4 times each. Variance component partitioning was used to compare the order of intra- and inter-observer variation. For the right and the left orbit, the inter-observer variance proportion was 90% and 79%, whereas intra-observer variance partition was 10% and 21%, respectively. The corresponding ratios 0.11 and 0.27 summarize the comparison of sources of variance. The overall reliability was 84%, representing the patients influence on the total variance. Intra-observer reliability for both orbits was 88%, 89%, 97% and 98% (mean over orbits), respectively for observers I to IV. Using the Spearman Brown prophecy formula it follows that two replications per patient are sufficient to ensure a minimum reproducibility of 90%, which is also confirmed by the low intra-observer variation. Furthermore, intra-class correlation as a measure of (multiple) observer reproducibility was 94%. In conclusion, due to the increased inter-observer variance proportion and the high variation in intra-observer reliability, evaluations of orbital SSTR scintigraphy have to be done by the same and experienced observer leading to comparable data. But an automatic and quantitative computerized technique for evaluation of these SPECT data should be exactly reproducible and probably lead to more accurate and representative results.

Adult↗

PubMed2000

Statistical methods for the comparison of measurements derived from orthodontic imaging.

Biometric comparison procedures for dental imaging methods with continuous outcome were reviewed, mainly concentrating on assessment and comparison of accuracy and precision according to the study design. Univariate graphical and numerical representations of corresponding deviations were summarized to derive a 'check list' of minimum information necessary to compare the measurement methods. The methods reviewed in this investigation are illustrated by the comparison of conventional (radiographic) cephalometry versus assessment using the DigiGraph in 50 female children. A paired t-test and the corresponding confidence interval approach were used to assess deviations in location of two imaging methods; the test procedures of Maloney/Rastogi, Hahn/Nelson, and Grubbs were surveyed as proposals for the comparison of precisions in paired data. The Krippendorff coefficient was used as an aggregate measure for method concordance. Since these methods can be performed by simple modification of standard options available in most statistical software packages, this review intends to enable dental researchers to choose the correct methods, and perform adequate data analysis and representation.

Algorithms↗