CT perfusion imaging of lung cancer: benefit of motion correction for blood flow estimates.

PURPOSE: CT perfusion (CTP) imaging assessment of treatment response in advanced lung cancer can be compromised by respiratory motion. Our purpose was to determine whether an original motion correction method could improve the reproducibility of such measurements. MATERIALS AND METHODS: The institutional review board approved this prospective study. Twenty-one adult patients with non-resectable non-small-cell lung cancer provided written informed consent to undergo CTP imaging. A motion correction method that consisted of manually outlining the tumor margins and then applying a rigid manual landmark registration algorithm followed by the non-rigid diffeomorphic demons algorithm was applied. The non-motion-corrected and motion-corrected images were analyzed with dual blood supply perfusion analysis software. Two observers performed the analysis twice, and the intra- and inter-observer variability of each method was assessed with Bland-Altman statistics. RESULTS: The 95% limits of agreement of intra-observer reproducibility for observer 1 improved from -84.4%, 65.3% before motion correction to -33.8%, 30.3% after motion correction (r = 0.86 and 0.97, before and after motion correction, p < 0.0001 for both) and for observer 2 from -151%, 96% to -49 %, 36 % (r = 0.87 and 0.95, p < 0.0001 for both). The 95% limits of agreement of inter-observer reproducibility improved from -168%, 154% to -17%, 25%. CONCLUSION: The use of a motion correction method significantly improves the reproducibility of CTP estimates of tumor blood flow in lung cancer. KEY POINTS: • Tumor blood flow estimates in advanced lung cancer show significant variability. • Motion correction improves the reproducibility of CT blood flow estimates in advanced lung cancer. • Reproducibility of blood flow measurements is critical to characterize lung tumor biology and the success of treatment in lung cancer.

Colorectal cancer screening in women: an underutilized lifesaver.

OBJECTIVE: Colorectal cancer (CRC) represents the third most common cancer diagnosed and a major cause of cancer-related deaths in women. Despite strong evidence that early screening decreases colorectal cancer incidence and mortality rates, colorectal cancer screening rates in women still lag significantly behind screening rates for breast and cervical cancers. Additionally, women have been found to be less likely than men to undergo CRC screening. This is despite the fact that the overall lifetime risk for the development of colorectal carcinoma is similar in both sexes. Barriers to screening have been found to be different for women compared with men. Screening adherence in women also appears to be associated with various social and demographic factors. CONCLUSION: CT colonography (CTC) is an accurate, minimally invasive, and well-tolerated examination that is newly endorsed by the American Cancer Society, U.S. Multisociety Task Force, and the American College of Radiology. Improved screening compliance may occur in women with further dissemination of CTC.

Patient-specific time to peak abdominal organ enhancement varies with time to peak aortic enhancement at MR imaging.

PURPOSE: To retrospectively evaluate the relationship between the times to peak enhancement of the liver, pancreas, and jejunum with respect to the time to peak aortic enhancement at magnetic resonance (MR) imaging. MATERIALS AND METHODS: The committee on human research approved this study and waived written informed consent. This study was HIPAA compliant. The study retrospectively identified 141 patients (63 men, 78 women; mean age, 57 years) who underwent abdominal MR imaging by using a test bolus that was monitored approximately every second for 2 minutes with a spoiled gradient-echo T1 transverse section through the upper abdomen. The times to peak enhancement of the aorta, liver, pancreas, and jejunum were recorded and correlated with the time to peak aortic enhancement, age, and sex by means of univariate and multivariate linear regression analyses. RESULTS: The mean time to peak aortic enhancement was 21.1 seconds (range, 8.7-41.8 seconds). The times to peak enhancement of the liver, pancreas, and jejunum were positively and linearly correlated with the time to peak aortic enhancement (r = 0.69, 0.86, and 0.80, respectively, all P < .001) and were 3.39, 1.64, and 2.04 times longer than the time to peak aortic enhancement, respectively. Age, sex, and history of heart disease did not give additional predictive information for determining the time to peak visceral enhancement. CONCLUSION: The times to peak enhancement of the liver, pancreas, and jejunum are linearly related to that of the aorta. These results could potentially allow tailored patient- and organ-specific scan delay optimization at contrast material-enhanced MR image evaluation.

Clinical Significance of Persistent Global and Focal Computed Tomography Nephrograms After Cardiac Catheterization and Their Relationships to Urinary Biomarkers of Kidney Damage and Procedural Factors: Pilot Study.

OBJECTIVES: We evaluate the relationships between persistent computed tomography (CT) nephrograms and acute kidney injury after cardiac catheterization (CC). We compare changes in urinary biomarkers kidney injury molecule 1 (KIM-1), cystatin C, and serum creatinine to procedural factors. MATERIALS AND METHODS: From 159 eligible patients without renal insufficiency (estimated glomerular filtration rate >60 mL/min), 40 random patients (age range, 42-81 years; mean age, 64 years; 25 men, 15 women) gave written informed consent to undergo unenhanced CT limited to their kidneys 24 hours after CC. Semiquantitative assessment for global nephrograms and quantitative assessment of focal nephrograms in each kidney was performed. Computed tomography attenuation (Hounsfield units) of the renal cortex was measured. Serum creatinine, KIM-1, and cystatin C were measured before and 24 hours after CC. RESULTS: Robust linear regression showed that both relative changes in KIM-1 and cystatin C had positive relationships with kidney CT attenuation (P = 0.012 and 0.002, respectively). Spearman rank correlation coefficient showed that both absolute changes and relative changes in KIM-1 and cystatin C had positive correlations with global nephrogram grades (P = 0.025 and 0.040, respectively, for KIM-1; P = 0.013 and 0.019, respectively, for cystatin C). CONCLUSIONS: Global nephrograms on unenhanced CT in patients who have undergone CC are significantly correlated with changes in urinary biomarkers for kidney damage.

CT of acute appendicitis: can diagnostic accuracy serve as a practical performance metric for readers specialized in abdominal imaging?

PURPOSE: To investigate diagnostic accuracy for acute appendicitis at computed tomography (CT) as a performance metric for radiologists specialized in abdominal imaging. MATERIALS AND METHODS: We retrospectively identified six attending abdominal imagers who each independently interpreted over 100 CT studies for suspected acute appendicitis. RESULTS: The mean number of studies per reader was 311 (range, 129-386). Mean reader diagnostic accuracy was 95.0% (range, 91.4-97.1%). Only one had a diagnostic accuracy (91.4%) that was significantly lower than all others. CONCLUSION: Diagnostic accuracy for acute appendicitis at CT may be an impractical performance metric for radiologists specialized in abdominal imaging.