Post-Whipple imaging in patients with pancreatic ductal adenocarcinoma: association with overall survival: a multivariate analysis.

PURPOSE: To compare the survival outcomes in patients with pancreatic ductal adenocarcinoma (PDAC) who had regular imaging surveillance with those who had clinical follow-up after Whipple. METHOD: We identified 229 patients, who underwent Whipple for resection of PDAC from 2005 to 2011, and had regular postoperative clinical follow-up at our hospital. Patients were retrospectively selected for two follow-up groups: imaging surveillance (IS) defined as routine imaging at scheduled intervals, vs. clinical (C) defined as imaging triggered by either change in clinical status or change in CA19-9. Follow-up was obtained through the hospital and Cancer Data Registry records. Survival was calculated from the date of surgery to death or last follow-up, with data censored as of March 13, 2013. Kaplan-Meier survival curves were compared using the log-rank test, and Cox regression models were used for multivariate analysis. RESULTS: Patients were followed for a mean period of 24.35 ± 2.56 months. IS-group underwent significantly more imaging (4.41 vs. 2.08 scans/year). The most frequent imaging was CT of chest and abdomen at 3-4 month interval. Univariate associations with overall survival were detected with post-Whipple ECOG status, T-stage, N-stage, tumor grade, surgical margin, recurrence, and IS. In multivariate analysis, grade, ECOG status, and recurrence were independent predictors of survival. Also, our predictor of interest, IS, was highly associated with longer survival in multivariate modeling (median overall survival, 30.4±3.85 (IS-group) vs. 17.1 ± 2.42 (C-groups) month, log-rank p = 0.002). CONCLUSION: Routine imaging surveillance was associated with prolonged overall survival post-Whipple in a multivariate model. This is a hypothesis-generating finding that should be studied prospectively and could ultimately impact surveillance guidelines.

Distinguishing hemangiomas from metastases on liver MRI performed with gadoxetate disodium: Value of the extended washout sign.

OBJECTIVE: To describe the enhancement pattern of hemangiomas with gadoxetate disodium and propose a new sign - the "extended washout sign" - to diagnose hemangiomas on hepatobiliary MR imaging. MATERIALS AND METHODS: In this retrospective IRB approved study, quantitative and qualitative image analysis of 45 hemangiomas and 37 metastases in 77 patients was performed. Gadoxetate disodium-enhanced MR imaging was obtained during arterial and portal venous phases as well as with delays of 3, 8, and 20min. Lesion signal intensity was measured at each phase. Quantitatively, extended washout was defined as a 10% or greater decrease in signal intensity from 8 to 20min on 3D gradient echo images. Statistical analysis was performed using unpaired Student's t-test. Qualitative analysis was also performed to assess observer confidence based on T2-weighted images, dynamic images, and combined early (8min) and late (20min) hepatobiliary phases. Extended washout was defined as a perceptible change in signal from 8 to 20min. RESULTS: On quantitative analysis, 84% of hemangiomas demonstrated a positive extended washout sign while only 18% of metastases did. Qualitatively, 78% of hemangiomas demonstrated a perceptible change in signal from 8 to 20min, while only 5.4% of metastases did. When extended washout was used in combination with T2 hyperintensity, specificity increased to 100%, with a sensitivity of 87% and area under the curve of 0.99. CONCLUSIONS: When combined with T2 signal intensity, the extended washout sign can be used to increase accuracy of differentiating hemangiomas from metastases on gadoxetate disodium-enhanced MRI.

Evaluation of renal quantitative T2* changes on MRI following administration of ferumoxytol as a T2* contrast agent.

PURPOSE: To evaluate the time-dependent changes in regional quantitative T2* maps of the kidney following intravenous administration of ferumoxytol. MATERIALS AND METHODS: Twenty-four individuals with normal kidney function underwent T2*-weighted MRI of the kidney before, immediately after, and 48 hours after intravenous administration of ferumoxytol at a dose of 4 mg/kg (group A, n=12) or 6 mg/kg (group B, n=12). T2* values were statistically analyzed using two-tailed paired t-tests. RESULTS: In group A, the percentage changes from baseline to immediate post and baseline to 48 hours were 85.3% and 64.2% for the cortex and 90.8% and 64.6% for the medulla, respectively. In group B, the percentage changes from baseline to immediate post and baseline to 48 hours were 85.2% and 73.4% for the cortex and 94.5% and 74% for the medulla, respectively. This difference was significant for both groups (P<0.0001). CONCLUSION: There is significant and differential uptake of ferumoxytol in the cortex and medulla of physiologically normal kidneys. This differential uptake may offer the ability to interrogate renal cortex and medulla with possible clinical applications in medical renal disease and transplant organ assessment. We propose an organ of interest based dose titration of ferumoxytol to better differentiate circulating from intracellular ferumoxytol particles.

Magnetic resonance imaging of pelvic metastases in male patients.

Magnetic resonance (MR) imaging offers a noninvasive tool for diagnosis of primary and metastatic pelvic tumors. The diagnosis of a pelvic metastatic lesion implies an adverse prognosis and dictates the management strategies. Knowledge of normal MR imaging anatomy of the pelvis and the signal characteristics of normal and abnormal structures is essential for accurate interpretation of pelvic MR imaging. This article reviews imaging manifestations of nodal, visceral, and musculoskeletal metastatic lesions of the pelvis along with current and evolving MR imaging techniques.

Depiction of celiac ganglia on positron emission tomography and computed tomography in patients with lung cancer.

OBJECTIVE: To differentiate imaging characteristics of celiac ganglia from metastatic lesion on positron emission tomography-computed tomography (PET-CT) in patients with lung cancer and correlate these findings to postmortem multidetector row computed tomography (MDCT). METHODS: One hundred twenty-nine patients were included. Imaging characteristics and fluorodeoxyglucose (FDG) avidity of the celiac ganglia were recorded. Postmortem MDCT of 20 subjects were reviewed. RESULTS: Celiac ganglia were identified unilaterally in 127 and bilaterally in 108 patients without abnormal FDG uptake. Postmortem images showed celiac ganglia in all cases with no significant difference compared to our patients. CONCLUSIONS: Familiarity with CT characteristics and FDG-avidity of celiac ganglia enable us to distinguish them from metastatic lesions in their vicinity.