Maximillian Reiser | PubMed Health

PubMed2007

Per-sextant localization and staging of prostate cancer: correlation of imaging findings with whole-mount step section histopathology.

OBJECTIVE: The objective of our study was to determine the diagnostic accuracy and interobserver agreement of 1.5-T prostatic MRI for per-sextant tumor localization and staging of prostate cancer as compared with whole-mount step section histopathology. MATERIALS AND METHODS: Combined endorectal-pelvic phased-array prostatic MRI scans obtained at 1.5 T of 106 patients with biopsy-proven prostate cancer who had undergone radical prostatectomy with whole-mount step section histopathology within 28 days of MRI were retrospectively analyzed by three independent abdominal radiologists (reviewers 1, 2, and 3). Sextants of the prostate (right and left base, middle, and apex) were evaluated for the presence of prostate cancer and extracapsular extension (ECE) using a 5-point confidence scale. Data were statistically analyzed using receiver operating characteristic (ROC) analysis. Interobserver variability was assessed by kappa statistics. For calculation of sensitivity and specificity, data from the 5-point confidence scale were dichotomized into negative (score of 1-3) or positive (score of 4 or 5) findings. RESULTS: Forty-one patients had ECE (tumor stage T3), and 65 patients had organ-confined disease (stage T2). Of 636 prostatic sextants, 417 were positive for prostate cancer and 135 were positive for ECE at histopathology. For prostate cancer localization, ROC analysis yielded area under the ROC curve (AUC) values ranging from 0.776 +/- 0.023 (SD) to 0.832 +/- 0.027. For the detection of ECE, the AUC values ranged from 0.740 +/- 0.054 to 0.812 +/- 0.045. Interobserver agreement (kappa) ranged from 0.49 to 0.60 for prostate cancer localization and from 0.59 to 0.67 for the detection of ECE. CONCLUSION: Using the sextant framework, independent observers reach similar accuracy with moderate to substantial agreement for the localization of prostate cancer and ECE by means of MRI of the prostate.

Anatomy, Cross-Sectional↗

PubMedDate not supplied

Dose reduction in multislice computed tomography.

OBJECTIVE: Evaluation of the attenuation-based on-line modulation of tube current on multislice computed tomography (CT) to explore the potential of this dose-saving technique. METHODS: Fifty-five patients with follow-up CT examinations were scanned without and with a CARE Dose (Siemens Medical Solutions, Erlangen, Germany). The applied dose, image noise, and subjective image quality were evaluated. The reduction in patient exposure was determined by obtaining the effective milliamperes per second for each reconstructed scan and the absolute dosage requirement for the whole scan. RESULTS: The dose reduction achieved by applying the attenuation-based on-line modulation of tube current was 29.4% +/- 3.1% (P=0.002) for all scans, 30.5% +/- 3.2% (P=0.002) for the thorax scans, 29.7% +/- 2.9% (P=0.002) for the abdomen scans, and 28.7% +/- 2.7% (P=0.003) for the thorax and abdomen scans together. No significant restrictions in image quality were observed. CONCLUSIONS: Remarkable dose reduction can be obtained using the attenuation-based on-line modulation of tube current on multislice CT without compromising image quality.

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