Taro Setoguchi

Parotid gland tumors: can addition of diffusion-weighted MR imaging to dynamic contrast-enhanced MR imaging improve diagnostic accuracy in characterization?

PURPOSE To determine the value of adding diffusion-weighted (DW) magnetic resonance (MR) imaging to dynamic contrast material-enhanced MR imaging when distinguishing between benign and malignant parotid tumors. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and the informed consent requirement was waived. The authors analyzed MR images of 50 lesions (36 benign, 14 malignant) in 47 patients. DW MR imaging and dynamic contrast-enhanced MR imaging were performed in all patients. Time-intensity curve (TIC) patterns were categorized as follows: type A, time to peak was more than 120 seconds; type B, time to peak was 120 seconds or less with high washout ratio (> or = 30%); type C, time to peak was 120 seconds or less with low washout ratio (< 30%); and type D, flat. The apparent diffusion coefficient (ADC) values were measured on DW MR images. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated for type A, B, and D tumors regarded as benign and for type C tumors regarded as malignant. On the basis of DW MR imaging results, ADC threshold values between pleomorphic adenomas and carcinomas and between Warthin tumors and carcinomas were selected. Diagnostic accuracy was compared before and after modification diagnosis referring to the ADC value obtained with the McNemar test. P < .05 was considered to indicate a significant difference. RESULTS ADC threshold values were 1.4 x 10(-3) mm(2)/sec between pleomorphic adenomas and carcinomas and 1.0 x 10(-3) mm(2)/sec between Warthin tumors and carcinomas. Accuracy (82% vs 94%) and positive predictive value (67% vs 92%) significantly improved with the addition of ADC values in the evaluation of patients with type B or C tumors. CONCLUSION A persistent or flat TIC pattern on dynamic contrast-enhanced MR images indicates benign disease, but there is added value from including the ADC value in the evaluation of tumors that show a plateau or washout TIC pattern.

Enhanced mass on contrast-enhanced breast MR imaging: Lesion characterization using combination of dynamic contrast-enhanced and diffusion-weighted MR images

To evaluate the diagnostic accuracy of a combination of dynamic contrast‐enhanced MR imaging (DCE‐MRI) and diffusion‐weighted MR imaging (DWI) in characterization of enhanced mass on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy.

Non-mass-like enhancement on contrast-enhanced breast MR imaging: Lesion characterization using combination of dynamic contrast-enhanced and diffusion-weighted MR images

PURPOSE To evaluate the diagnostic accuracy of a combination of dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion-weighted MR imaging (DWI) in characterization of lesions showing non-mass-like enhancement on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy. MATERIALS AND METHODS We analyzed consecutive MR images in 45 lesions showing non-mass like enhancement in 41 patients. We analyzed lesion size, distribution, internal enhancement, kinetic curve pattern, and apparent diffusion coefficient (ADC) values. We applied univariate and multivariate analyses to find the strongest indicators for malignancy. In a validation study, 22 non-mass-like enhancement lesions in 21 patients were examined. We calculated diagnostic accuracy when we presume category 4b, 4c, and 5 lesions as malignant or high to moderate suspicion for malignancy, and category 4a and 3 as low suspicion for malignancy or benign. RESULTS Segmental distribution (P=0.018), clumped internal enhancement (P=0.005), and ADC less than 1.3 x 10(-3) mm(2)/s (P=0.047) were the strongest MR indicators of malignancy. In a validation study, sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 87% (13/15), 86% (6/7), 93% (13/14), 75% (6/8) and 86% (19/22), respectively. CONCLUSION The combination of DCE-MRI and DWI showed high diagnostic accuracy in characterization of non-mass-like enhancement lesions on breast MR images.

Detection of non-palpable breast cancer in asymptomatic women by using unenhanced diffusion-weighted and T2-weighted MR imaging: comparison with mammography and dynamic contrast-enhanced MR imaging

ObjectiveTo compare the detectability of non-palpable breast cancer in asymptomatic women by using mammography (MMG), dynamic contrast-enhanced MR imaging (DCE-MRI) and unenhanced MR imaging with combined diffusion-weighted and T2-weighted images (DWI + T2WI).MethodsForty-two lesions in 42 patients with non-palpable breast cancer in asymptomatic women were enrolled. For the reading test, we prepared a control including 13 normal and 8 benign cases. Each imaging set included biplane MMG, DCE-MRI and DWI + T2WI. Five readers were asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of cancer and the BI-RADS category. Confidence level results were used to construct receiver operating characteristic analysis. Sensitivity and specificity were calculated for each technique.ResultsDWI + T2WI showed higher observer performances (area under the curve, AUC, 0.73) and sensitivity (50%) for the detection of non-palpable breast cancer than MMG alone (AUC 0.64; sensitivity 40%) but lower than those of DCE-MRI (AUC 0.93; sensitivity 86%). A combination of MMG and DWI + T2WI exhibited higher sensitivity (69%) compared with that of MMG alone (40%).ConclusionDWI + T2WI could be useful in screening breast cancer for patients who cannot receive contrast medium and could be used as a new screening technique for breast cancer.

Pretreatment Apparent Diffusion Coefficient of the Primary Lesion Correlates With Local Failure in Head-and-Neck Cancer Treated With Chemoradiotherapy or Radiotherapy

PURPOSE This study was performed to evaluate whether the apparent diffusion coefficient (ADC) of a primary lesion correlates with local failure in primary head-and-neck squamous cell carcinoma (HNSCC) treated with chemoradiotherapy or radiotherapy. METHODS AND MATERIALS We retrospectively studied 38 patients with primary HNSCC (12 oropharynx, 20 hypopharynx, 4 larynx, 2 oral cavity) treated with chemoradiotherapy or radiotherapy with radiation dose to gross tumor volume equal to or over 60 Gy and who underwent pretreatment magnetic resonance imaging, including diffusion-weighted imaging. Ten patients developed local failure during follow-up periods of 2.0 to 9.3 months, and the remaining 28 showed local control during follow-up periods of 10.5 to 31.7 months. The variables that could affect local failure (age, tumor volume, ADC, T stage, N stage, dose, treatment method, tumor location, and overall treatment time) were analyzed using logistic regression analyses for all 38 patients and for 17 patients with Stage T3 or T4 disease. RESULTS In univariate logistic analysis for all 38 cases, tumor volume, ADC, T stage, and treatment method showed significant (p < 0.05) associations with local failure. In multivariate analysis, ADC and T stage revealed significance (p < 0.01). In univariate logistic analysis for the 17 patients with Stage T3 or T4 disease, ADC and dose showed significant (p < 0.01) associations with local failure. In multivariate analysis, ADC alone showed significance (p < 0.05). CONCLUSIONS The results suggest that pretreatment ADC, along with T stage, is a potential indicator of local failure in HNSCC treated with chemoradiotherapy or radiotherapy.

Alteration of proton diffusivity associated with passive muscle extension and contraction

To determine whether passive muscle extension and contraction affect the proton diffusivity of the muscle.

Effect of cardiac function on aortic peak time and peak enhancement during coronary CT angiography

PURPOSE To examine the manner in which cardiac function affects the magnitude and timing of aortic contrast enhancement during coronary CT angiography (CTA). MATERIALS AND METHODS Twenty-nine patients (21 men, 8 women; mean age, 64.4+/-13.4 years; mean weight, 59.4+/-10.3 kg) underwent measurement of cardiac output within 2 weeks of coronary CTA. The cardiac output of each patient was measured by the thermodilution technique and the cardiac index was calculated from the body surface area. During coronary CTA, attenuation of the descending aorta was measured at the workstation every 3s. The aortic peak time (APT) and aortic peak enhancement (APE) of each patient were calculated. Pearsons correlation coefficient analysis was used to investigate the relationships between the cardiac output or cardiac index and APT or APE. Furthermore, the relationship between patient factors or parameters on test bolus injection and APT or APE was also evaluated. RESULTS The range of cardiac output, cardiac index, APT, and APE was 1.55-10.46 L/min (mean: 4.77+/-2.13), 1.11-5.30 L/(min-m(2)) (mean: 3.28+/-1.08), 25-51 s (mean: 38.3+/-7.5), and 273.1-598.1 HU (mean: 390.4+/-72.1), respectively. With an increase in the cardiac index, both APT (r=-0.698, p<0.0001) and APE (r=-0.573, p=0.0009) decreased. There were significant correlations between the patient body weight and APT and APE with the test bolus injection, and with APT and APE during coronary CTA. CONCLUSION The APT and APE during coronary CTA are closely related to cardiac function.

Diagnostic performance in differentiation of breast lesion on digital mammograms: comparison among hard-copy film, 3-megapixel LCD monitor, and 5-megapixel LCD monitor

We compared observer performance of digital mammography among hard-copy readings and soft-copy readings using 3-megapixel (3M) and 5-megapixel (5M) liquid crystal display (LCD) monitors. Five experienced radiologists assessed 80 mammograms of 40 cancers and 40 benign lesions. There were no significant differences among the average A(z) of three modalities and among the κ values for intra- and interobserver agreement. The soft-copy reading using the 3M LCD monitor took a slightly longer time, although there were no significant differences.

Detection of breast cancer by soft-copy reading of digital mammograms: comparison between a routine image-processing parameter and high-contrast parameters.

Background: Recent studies have reported the clinical usefulness of the soft-copy reading of mammograms. However, image-processing parameters for soft-copy reading of digital mammograms have not been established. Purpose: To compare observer performance in detecting breast cancer by soft-copy reading of digital mammograms using a routine image-processing parameter versus each of several high-contrast parameters. Material and Methods: The mammograms of 154 breasts, including 48 abnormal breasts with breast cancer and 106 normal breasts, were examined. Cancers were classified into 34 mass-dominant cancers, 11 microcalcification-dominant cancers, two cancers showing only architectural distortion, and one cancer without abnormal findings. All mammograms were performed using a computed radiography (CR) system. Each image was processed using GA (1.2), which was the contrast parameter recommended by the manufacturer for hard-copy film, GA (1.4), GA (1.6), and GA (1.8). These images were displayed on 5-megapixel (M) liquid-crystal display monitors. Five experienced radiologists classified them into BI-RADS category 1–2 or 3–5, and were also asked to rate the images on a scale of 0 to 100 for the likelihood of the presence of masses and microcalcifications in each breast. Results: In mass-dominant cancers of dense breast tissue, the mean sensitivities of GA (1.2), GA (1.4), GA (1.6), and GA (1.8) were 32.7, 38.2, 36.4, and 40.0, and the AZ values were 0.67, 0.73, 0.71, and 0.73, respectively; in microcalcification-dominant cancers, the mean sensitivities were 80.0, 74.5, 80.0, and 78.2, respectively; however, there were no significant differences among them. Conclusion: High-contrast parameters tended to show relatively high sensitivity and AZ values in the detection of masses in dense breast tissue, but relatively low sensitivity for microcalcifications.

Nonspecific interstitial pneumonia after peripheral blood stem cell transplantation in an 11-year-old boy

Late-onset pulmonary complications after peripheral blood stem cell transplantation include various conditions such as opportunistic infections and interstitial pneumonias. It is sometimes difficult to diagnose interstitial pneumonias because there is substantial overlap in their computed tomography appearances. We present a case of an 11-year-old boy who consecutively developed pulmonary infection and cellular nonspecific interstitial pneumonia 9 months after peripheral blood stem cell transplantation for recurrent acute lymphocytic leukemia.