Assessment of Left Ventricular Parameters Using 16-MDCT and New Software for Endocardial and Epicardial Border Delineation

Thomas Schlosser; Konstantin Pagonidis; Christoph U. Herborn; Peter Hunold; Kai-Uwe Waltering; Thomas C. Lauenstein; Jörg Barkhausen

Disclosures

Am J Roentgenol. 2005;184(3):765-773. 

In This Article

Results

Of 18 patients referred for CT coronary angiography, one had to be excluded from further analysis because of arrhythmias that occurred during data acquisition. This patient did not undergo the MRI examination. In the remaining 17 patients, CT and MRI examinations were successfully accomplished without any complications. The mean heart rate was 58 ± 4 beats per minute during the CT examinations. During MRI, the mean heart rate was 65 ± 8 beats per minute. Five patients had β-blockers in their standard medication, and in four patients β-blockers had to be injected IV before CT. CT and MR image quality was adequate in all patients. The mean duration of analysis using the CT automated contour detection algorithm was 1 min 04 sec ± 21 sec and 3 min 27 sec ± 46 sec for manual tracing, respectively. The mean duration of analysis of MR data was 4 min 01 sec ± 37 sec.

The mean EDV measured on MRI was 118.7 ± 43.6 mL (range, 65–239 mL). CT values derived from automated contour detection (CTauto, 137.1 ± 45.7 mL; range, 75–254 mL) and from manual tracing (CTmanual, 134.2 ± 39.9 mL; range, 78–237 mL) were significantly higher than with MRI (MRI vs CTauto, p < 0.05; mean difference, –20.3 ± 15.7 mL; MRI vs CTmanual, p < 0.05; mean difference, –17.2 ± 13.1 mL). EDV derived from both CT algorithms was not significantly different (CTauto vs CTmanual, p > 0.05; mean difference, 3.1 ± 7.1 mL) (Fig. 1 and Fig. 2).

Left ventricular end-diastolic volume assessed using MRI and CT. CTauto = automatic contour detection; CTMAN = manual contour tracing.

A—C Bland-Altman plots of end-diastolic volume. Bland-Altman plots were assessed using MRI versus CTauto (automated contour detection, A ), MRI versus CTmanual (manual tracing, B ), and CTauto versus CTmanual ( C ).

The mean ESV calculated from the MR data sets was 50.1 ± 33.5 mL (range, 16–143 mL). ESV values derived from both CT algorithms (CTauto, 58.8 ± 34.2 mL; range, 11–129 mL; CTmanual, 58.1 ± 30.1 mL; range, 21–130 mL) were significantly higher than with MRI (MRI vs CTauto, p < 0.05; mean difference, –9.2 ± 13.9 mL; MRI vs CTmanual, p < 0.05; mean difference, –9.1 ± 10.9 mL). ESV values from the CT examination assessed by automated and manual measurements were not significantly different (CTauto vs CTmanual, p > 0.05; mean difference, 0.1 ± 7.1 mL) (Fig. 3 and Fig. 4).

Left ventricular end-systolic volume assessed using MRI and CT. CTauto = automatic contour detection; CTMAN = manual contour tracing.

A—C Bland-Altman plots of end-systolic volume. Bland-Altman plots were assessed using MRI versus CTauto (automated contour detection, A ), MRI versus CTmanual (manual tracing, B ), and CTauto versus CTmanual ( C ).

EF assessed on MRI (59.9% ± 14.4%; range, 18–76%) was slightly higher but not significantly different from CT values derived by automated contour detection (59.2% ± 13.7%; range, 31–85%) and manual tracing (58.1% ± 11.9%; range, 30–73%; MRI vs CTauto, p > 0.05; mean difference, 1.0% ± 9.0%; MRI vs CTmanual, p > 0.05; mean difference, 2.6% ± 7.3%). EF derived from both CT algorithms was not significantly different (CTauto vs CTmanual, p > 0.05; mean difference, 1.5% ± 4.4%) (Fig. 5 and Fig. 6).

Ejection fraction assessed using MRI and CT. CTauto = automatic contour detection; CTMAN = manual contour tracing.

A—C Bland-Altman plots of ejection fraction. Bland-Altman plots were assessed using MRI versus CTauto (automated contour detection, A ), MRI versus CTmanual (manual tracing, B ), and CTauto versus CTmanual ( C ).

The highest mean LVM was assessed using MRI (142.7 ± 38.4 g; range, 87–224 g). These data were significantly different from CT values derived by automated contour detection (130.9 ± 29.1 g; range, 89–175 g) and manual tracing (133.7 ± 33.2 g; range, 92–198 g; MRI vs CTauto, p < 0.05; mean difference, 11.7 ± 15.9 g; MRI vs CTmanual, p < 0.05; mean difference, 8.3 ± 12.4 g). LVM measurements derived from both CT algorithms were not significantly different (CTauto vs CTmanual, p > 0.05; mean difference, –3.3 ± 7.0 g) (Fig. 7 and Fig. 8

Left ventricular mass assessed using MRI and CT. CTauto = automatic contour detection; CTMAN = manual contour tracing.

A—C Bland-Altman plots of left ventricular mass. A—C, Bland-Altman plots were assessed using MRI versus CTauto (automated contour detection, A ), MRI versus CTmanual (manual tracing, B ), and CTauto versus CTmanual ( C ).

Examples of end-diastolic and end-systolic MR and CT images and automatic detected and manually traced endo- and epicardial contours are displayed in Figure 9.

A—B Examples of end-diastolic and end-systolic MR and CT images. A ) End-diastolic MR ( top row ) and CT images and automatically detected ( center row ) and manually traced ( bottom row ) endo- and epicardial contours. Only each second short-axis slice is displayed. B ) End-systolic MR ( top row ) and CT images and automatically detected ( center row ) and manually traced ( bottom row ) endo- and epicardial contours. Only each second short-axis slice is displayed.

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