Prognostic implications of the magnetic resonance imaging appearance in papillary renal cell carcinoma.

OBJECTIVE: To evaluate the prognostic implications of the MRI appearance and pathological features of papillary renal cell carcinoma (pRCC). METHODS: A total of 128 pRCC in 115 patients who underwent preoperative MRI were characterised in terms of pathological type (type 1 vs. type 2), MRI appearance (focal vs. infiltrative) and additional MRI features. Patients were classified on the basis of the presence or absence of metastatic disease. RESULTS: There were 65 focal type 1, 54 focal type 2 and 9 infiltrative pRCC. All infiltrative pRCC were of histopathological type 2. Renal vein thrombus was present in 89 % of infiltrative pRCC and no cases of focal pRCC. Metastatic disease was observed in 3.7 % of focal type 1, 7.5 % of focal type 2 and 75.0 % of infiltrative type 2 pRCC. Infiltrative MRI appearance was a significant predictor of metastatic disease, independent of pathological type, size and T stage (P ≤ 0.020). Among focal pRCC on MRI, pathological type 2 was not a significant predictor of metastatic disease (P = 0.648). No combination of features achieved significantly greater accuracy for predicting metastatic disease than renal vein thrombus alone (P > 0.5). CONCLUSION: Infiltrative MRI appearance and renal vein thrombus identify a subset of pathological type 2 pRCC at a significantly increased risk of metastatic disease.

Automated computer-derived prostate volumes from MR imaging data: comparison with radiologist-derived MR imaging and pathologic specimen volumes.

PURPOSE: To compare prostate gland volume (PV) estimation of automated computer-generated multifeature active shape models (MFAs) performed with 3-T magnetic resonance (MR) imaging with that of other methods of PV assessment, with pathologic specimens as the reference standard. MATERIALS AND METHODS: All subjects provided written informed consent for this HIPAA-compliant and institutional review board-approved study. Freshly weighed prostatectomy specimens from 91 patients (mean age, 59 years; range, 42-84 years) served as the reference standard. PVs were manually calculated by two independent readers from MR images by using the standard ellipsoid formula. Planimetry PV was calculated from gland areas generated by two independent investigators by using manually drawn regions of interest. Computer-automated assessment of PV with an MFA was determined by the aggregate computer-calculated prostate area over the range of axial T2-weighted prostate MR images. Linear regression, linear mixed-effects models, concordance correlation coefficients, and Bland-Altman limits of agreement were used to compare volume estimation methods. RESULTS: MFA-derived PVs had the best correlation with pathologic specimen PVs (slope, 0.888). Planimetry derived volumes produced slopes of 0.864 and 0.804 for two independent readers when compared with specimen PVs. Ellipsoid formula-derived PVs had slopes closest to one when compared with planimetry PVs. Manual MR imaging and MFA PV estimates had high concordance correlation coefficients with pathologic specimens. CONCLUSION: MFAs with axial T2-weighted MR imaging provided an automated and efficient tool with which to assess PV. Both MFAs and MR imaging planimetry require adjustments for optimized PV accuracy when compared with prostatectomy specimens.

Arterial spin-labeling MR imaging of renal masses: correlation with histopathologic findings.

PURPOSE: To assess the value of arterial spin-labeling (ASL) perfusion magnetic resonance (MR) imaging in the characterization of solid renal masses by using histopathologic findings as the standard of reference. MATERIALS AND METHODS: This prospective study was compliant with HIPAA and approved by the institutional review board. Informed consent was obtained from all patients before imaging. Forty-two consecutive patients suspected of having renal masses underwent ASL MR imaging before their routine 1.5-T clinical MR examination. Mean and peak tumor perfusion levels were obtained by one radiologist, who was blinded to the final histologic diagnosis, by using region of interest analysis. Perfusion values were correlated with histopathologic findings by using analysis of variance. A linear correlation model was used to evaluate the relationship between tumor size and perfusion in clear cell renal cell carcinoma (RCC). P < .05 was considered indicative of a statistically significant difference. RESULTS: Histopathologic findings were available in 34 patients (28 men, six women; mean age ± standard deviation, 60.4 years ± 11.7). The mean perfusion of papillary RCC (27.0 mL/min/100 g ± 15.1) was lower than that of clear cell RCC (171.6 mL/min/100 g ± 61.2, P = .001), chromophobe RCC (152.9 mL/min/100 g ± 80.7, P = .04), unclassified RCC (208.0 mL/min/100 g ± 41.1, P = .001), and oncocytoma (373.9 mL/min/100 g ± 99.2, P < .001). The mean and peak perfusion levels of oncocytoma (373.9 mL/min/100 g ± 99.2 and 512.3 mL/min/100 g ± 146.0, respectively) were higher than those of papillary RCC (27.0 mL/min/100 g ± 15.1 and 78.2 mL/min/100 g ± 39.7, P < .001 for both), chromophobe RCC (152.9 mL/min/100 g ± 80.7 and 260.9 mL/min/100 g ± 61.9; P < .001 and P = .02, respectively), and unclassified RCC (208.0 mL/min/100 g ± 41.1 and 273.3 mL/min/100 g ± 83.4; P = .01 and P = .03, respectively). The mean tumor perfusion of oncocytoma was higher than that of clear cell RCC (P < .001). CONCLUSION: ASL MR imaging enables distinction among different histopathologic diagnoses in renal masses on the basis of their perfusion level. Oncocytomas demonstrate higher perfusion levels than RCCs, and papillary RCCs exhibit lower perfusion levels than other RCC subtypes.

Extrahepatic metastasis risk of hepatocellular carcinoma based on α-fetoprotein and tumor staging parameters at cross-sectional imaging.

BACKGROUND: Extrahepatic metastases have important implications in the clinical management of hepatocellular carcinoma (HCC). The purpose of this study was to validate tumor staging parameters and serum AFP as risk factors of HCC metastasis. PATIENTS AND METHODS: In this retrospective case-control study, patients with a new diagnosis of HCC (N=236), median age 57 years (range 28-89 years), and male-to-female ratio of 183/53 were divided into a "no-met" group (N=101) without extrahepatic metastasis or a "met" group with extrahepatic metastases (N=135). Metastasis risk factors based on tumor staging parameters (size, number, infiltration, and vascular invasion) and serum AFP level were calculated as odds ratio (OR). Sensitivities of the risk factors as metastasis screening tests were also calculated. RESULTS: AFP >400 µg/mL, index tumor size >5 cm, and vascular invasion individually had strong association with metastasis, with OR (95% confidence interval) of 11.5 (5.9-22.1), 17.7 (9.0-34.8), and 18.9 (8.2-43.9), respectively, but with moderate sensitivities as metastasis screening tests, with 71.9% (65.7-77.3), 75.6% (69.6-80.7), and 58.5% (52.1-64.7), respectively. Composite multiparametric criteria, eg, a logical union of 1) tumor size outside of Milan criteria, 2) AFP threshold >35 µg/mL, and 3) vascular invasion, had excellent OR up to 55.6 (13.0-237.1) with screening sensitivity 98.5% (95.8-99.6). CONCLUSION: Serum AFP, tumor size, and vascular invasion are strongly associated with extrahepatic metastasis of HCC, especially when combined into a multiparametric metastasis prediction criterion.