CT-guided high-dose-rate brachytherapy of unresectable hepatocellular carcinoma

Strahlentherapie und Onkologie - The purpose of the present study was to evaluate the clinical outcome of CT-guided high-dose-rate brachytherapy (CT-HDRBT) in patients with unresectable...     

Technical and Clinical Aspects of Coronary Computed Tomography Angiography

Coronary computed tomography angiography is an emerging imaging technique that has attracted much scientific attention over the past years. Improved scanner technology and dedicated protocols have made noninvasive coronary a reliable diagnostic test in patients with suspected coronary artery disease (CAD). Several technical steps such as the introduction of 64-slice scanners, multisegment reconstruction, and dual-source computed tomography have substantially improved temporal and spatial resolution. With these sophistications, coronary computed tomography angiography enables reliable exclusion of CAD in patients with low to intermediate pretest probability of having CAD or with inconsistent ischemia test results.     

Size determination and response assessment of liver metastases with computed tomography—Comparison of RECIST and volumetric algorithms

Objective

To compare different three-dimensional volumetric algorithms (3D-algorithms) and RECIST for size measurement and response assessment in liver metastases from colorectal and pancreatic cancer.

Methods

The volumes of a total of 102 liver metastases in 45 patients (pancreatic cancer, n = 22; colon cancer, n = 23) were estimated using three volumetric methods (seeded region growing method, slice-based segmentation, threshold-based segmentation) and the RECIST 1.1 method with volume calculation based on the largest axial diameter. Each measurement was performed three times by one observer. All four methods were applied to follow-up on 55 liver metastases in 29 patients undergoing systemic treatment (median follow-up, 3.5 months; range, 1–10 months). Analysis of variance (ANOVA) with post hoc tests was performed to analyze intraobserver variability and intermethod differences.

Results

ANOVA showed significant higher volumes calculated according to the RECIST guideline compared to the other measurement methods (p < 0.001) with relative differences ranging from 0.4% to 41.1%. Intraobserver variability was significantly higher (p < 0.001) for RECIST and threshold based segmentation (3.6–32.8%) compared with slice segmentation (0.4–13.7%) and seeded region growing method (0.6–10.8%). In the follow-up study, the 3D-algorithms and the assessment following RECIST 1.1 showed a discordant classification of treatment response in 10–21% of the patients.

Conclusions

This study supports the use of volumetric measurement methods due to significant higher intraobserver reproducibility compared to RECIST. Substantial discrepancies in tumor response classification between RECIST and volumetric methods depending on applied thresholds confirm the requirement of a consensus concerning volumetric criteria for response assessment.     

Evaluation of right ventricular function with multidetector computed tomography: comparison with magnetic resonance imaging and analysis of inter- and intraobserver variability

This study was performed to prospectively compare multidetector computed tomography (MDCT) with 16 simultaneous sections and magnetic resonance imaging (MRI) for the assessment of global right ventricular function in 50 patients. MDCT using a semiautomatic analysis tool showed good correlation with MRI for end-diastolic volume (EDV, r = 0.83, p < 0.001), end-systolic volume (ESV, r = 0.86, p < 0.001) and stroke volume (SV, r = 0.74, p < 0.001), but only a moderate correlation for the ejection fraction (EF, r = 0.67, p < 0.001). Bland Altman analysis revealed a slight, but insignificant overestimation of EDV (4.0 ml, p = 0.08) and ESV (2.4 ml, p = 0.07), and underestimation of EF (0.1%, p = 0.92) with MDCT compared with MRI. All limits of agreement between both modalities (EF: ±15.7%, EDV: ±31.0 ml, ESV: ±18.0 ml) were in a moderate but acceptable range. Interobserver variability of MDCT was not significantly different from that of MRI. For MDCT software, the post-processing time was significantly longer (19.6 ± 5.8 min) than for MRI (11.8 ± 2.6 min, p < 0.001). Accurate assessment of right ventricular volumes by 16-detector CT is feasible but still rather time-consuming.     

Diffusion‐weighted echo‐planar magnetic resonance imaging for the assessment of tumor cellularity in patients with soft‐tissue sarcomas

Purpose

To investigate the eligibility of diffusion‐weighted imaging (DWI) for the evaluation of tumor cellularity in patients with soft‐tissue sarcomas.

Materials and Methods

Thirty consecutive patients with a total of 31 histologically‐proven soft‐tissue sarcomas prospectively underwent magnetic resonance imaging (MRI) including DWI with echo‐planar imaging (EPI) technique immediately before open biopsy (N = 1) or tumor resection (N = 30). Fourteen patients had no previous anticancer treatment, 16 had received neoadjuvant therapy. Tumor cellularity as determined from histological sections was compared with minimum apparent diffusion coefficient (ADC).

Results

Tumor cellularity correlated well with minimum ADC in a linear fashion, with a Pearson correlation coefficient of –0.88 (95% confidence interval [CI]: –0.75 to –0.96). This relationship was not influenced by prior anticancer treatment. There was only a tendency toward lower ADC in tumor with higher grading but no significant dependency (P = 0.08).

Conclusion

DWI has proven useful for the assessment of tumor cellularity in soft‐tissue sarcomas. In result, DWI may be used as a powerful noninvasive tool to monitor responses of cytotoxic treatment as reflected by changes in tumor cellularity. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.