Silvia D. Chang

Combined diffusion‐weighted and dynamic contrast‐enhanced MRI for prostate cancer diagnosis—Correlation with biopsy and histopathology

To determine whether the combination of diffusion‐weighted (DW) and dynamic contrast‐enhanced (DCE) MRI provides higher diagnostic sensitivity for prostate cancer than each technique alone.

Uterine Arteriovenous Malformations From Diagnosis to Treatment

Objective. The purpose of this study was to describe the sonographic features of uterine arteriovenous malformations (AVMs) and to describe the role and clinical outcome after transcatheter arterial embolization of symptomatic uterine AVMs. Methods. In our institution, over a 4‐year period, symptomatic uterine AVMs were diagnosed in 21 women. Endovaginal sonography with gray scale, color, and spectral Doppler imaging was performed on all patients. Fourteen patients required therapeutic angiography/embolization to control bleeding. These 14 patients had follow‐up endovaginal sonography 24 hours after the procedure. Results. The sonographic gray scale findings of uterine AVMs were nonspecific. The most common finding was subtle myometrial heterogeneity (n = 14), whereas other patients had small anechoic spaces in the myometrium (n = 7). Color Doppler sonography showed a tangle of vessels with multidirectional high‐velocity flow that produced a “color mosaic” pattern. Spectral Doppler analysis showed arteriovenous shunting with high‐velocity, low‐resistance flow. Fourteen patients required transcatheter arterial embolization to control bleeding. Thirteen of 14 patients had no sonographic evidence of a residual AVM 24 hours after the procedure. One of 14 patients had a residual AVM requiring additional embolization. One patient had recurrent bleeding at 4 months and required further embolization. The remaining 7 patients were treated conservatively. Conclusions. Endovaginal sonography is the imaging modality of choice in patients with abnormal uterine bleeding. Routine use of color and spectral Doppler sonography allows one to confidently make the correct diagnosis. Transcatheter arterial embolization is an excellent treatment option. Endovaginal sonography should be used to monitor postembolization outcomes.

MRI of spinal hardware: comparison of conventional T1-weighted sequence with a new metal artifact reduction sequence

Abstract Objective. This study was designed to compare diagnostic quality of MR images of patients with spinal hardware acquired using a conventional T1-weighted spin-echo sequence and a new metal artifact reduction sequence (MARS). Conclusion. The new MARS sequence effectively reduces the degree of tissue-obscuring artifact produced by spinal fixation hardware and subjectively improves image quality compared with the conventional T1-weighted spin-echo sequence.

Comparison between Population Average and Experimentally Measured Arterial Input Function in Predicting Biopsy Results in Prostate Cancer

RATIONALE AND OBJECTIVES To test whether individually measured arterial input function (AIF) provides more accurate prostate cancer diagnosis then population average AIF when dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data are acquired with limited temporal resolution. MATERIALS AND METHODS Twenty-six patients with a high clinical suspicion for prostate cancer and no prior treatment underwent DCE MRI examination at 3.0 T before biopsy. DCE MRI data were fitted to a pharmacokinetic model using three forms of AIF: an individually measured, a local population average, and a literature double exponential population average. Receiver operating characteristic (ROC) analysis was used to correlate MRI with the biopsy results. Goodness of fit (chi(2)) for the three AIFs was compared using nonparametric Mann-Whitney test. RESULTS Average volume transfer constant (K(trans)) values were significantly higher in tumor than in normal peripheral zone for all three AIFs. The individually measured and the local population average AIFs had the highest sensitivity (76%), whereas the double exponential AIF had the highest specificity (82%). The areas under the ROC curves were not significantly different between any of the AIFs (0.81, 0.76, and 0.81 for the individually measured, local population average, and double exponential AIFs, respectively). chi(2) was not significantly different for the three AIFs; however, it was significantly higher in enhancing than in nonenhancing regions for all three AIFs. CONCLUSIONS These results suggest that, when DCE MRI data are acquired with limited temporal resolution, experimentally measured individual AIF is not significantly better than population average AIF in predicting the biopsy results in prostate cancer.

Multiparametric MRI maps for detection and grading of dominant prostate tumors

To develop an image‐based technique capable of detection and grading of prostate cancer, which combines features extracted from multiparametric MRI into a single parameter map of cancer probability.

Acute appendicitis within a femoral hernia: multidetector CT findings

We present a case of surgically proved acute appendicitis strangulated in a femoral hernia sac. Multidetector computed tomography with multiplanar reformations was thought to be helpful in evaluating acute appendicitis in a femoral hernia sac. An awareness of computed tomographic findings may avoid a delay in recognition and management of a patient with this unusual condition.

Multiparametric Magnetic Resonance Imaging Enhances Detection of Significant Tumor in Patients on Active Surveillance for Prostate Cancer

OBJECTIVE To determine whether multiparametric magnetic resonance imaging (MRI) of the prostate (mpMRI) combined with MRI fusion technology during transrectal ultrasound-guided biopsy can enhance the detection of significant disease in patients with apparent low-risk prostate cancer on active surveillance (AS). MATERIALS AND METHODS We reviewed the charts of 603 patients on AS for localized prostate cancer between January 2006 and September 2013. mpMRI before repeat transrectal ultrasound-guided biopsy was obtained in 111 patients, of whom 69 underwent subsequent fusion biopsy (39 true and 30 cognitive) in addition to standard template biopsy. The results of fusion biopsy were compared with the standard biopsy. The primary endpoint was termination of AS. RESULTS mpMRI detected 118 suspicious lesions in 70 patients (63%). Of these, 42 patients (60%) had lesions with Prostate imaging, reporting, and data system (PIRADS) score 3, and 28 patients (40%) had PIRADS score 4 or 5 lesions. AS was terminated in 27 (24.3%) of the 111 patients who underwent mpMRI. Seventeen patients stopped AS based on mpMRI findings including 16 for pathologic progression in target biopsies and 1 for lesion size increase, whereas the other 10 stopped AS because of pathologic progression in the standard cores (n = 6) or other reasons (n = 4). Use of mpMRI increased the rate of AS termination (27 vs. 10; P = .002). On multivariate analysis, PIRADS score 4-5 (vs. 3) was the only significant predictor of AS termination (P = .015). CONCLUSION These preliminary retrospective findings suggest that mpMRI with subsequent fusion biopsy enhances the identification of AS patients requiring definitive treatment.

Imaging Assessment of Congenital and Acquired Abnormalities of the Portal Venous System

Abnormalities of the portal venous system are a heterogeneous group of conditions that can cause substantial morbidity and mortality and may lead to complications during surgery or percutaneous interventions involving the portal venous system. High-resolution computed tomography, ultrasonography, and magnetic resonance imaging permit a comprehensive, noninvasive evaluation of the portal venous system, enabling the detection of both structural and functional abnormalities. However, an understanding of the embryologic development of the normal portal venous anatomy and anatomic variants is essential to accurately interpret the imaging findings. Knowledge of the characteristic appearances of abnormalities of the portal venous system allows a more confident diagnosis, permitting timely treatment and more informed guidance of surgical procedures and percutaneous interventions, which may lead to an improved outcome.

In vivo 3T and ex vivo 7T diffusion tensor imaging of prostate cancer: Correlation with histology.

The purpose of this work was to test whether fractional anisotropy (FA) can contribute to the diagnosis and grading of prostate cancer. Turbo spin echo T2-weighted (T2W) and single shot echo planar imaging diffusion tensor imaging (EPI DTI) data were collected from 13 subjects with biopsy proven prostate cancer prior to surgical removal of the gland. Rapid acquisition with relaxation enhancement (RARE) T2W and spin-echo DTI data were acquired ex-vivo from the fixed prostatectomy specimens. Digitized whole mount histology sections, examined and annotated by a pathologist, were registered to the in-vivo and ex-vivo DTI data, and the average values of apparent diffusion coefficient (ADC) and FA were calculated from ROIs encompassing normal and cancerous peripheral zone (PZ). In addition, Monte Carlo simulations were carried out to assess the dependence of the apparent FA on the ADC values for different signal to noise ratios (SNRs). ADC values were significantly lower in tumors than in normal PZ both in-vivo and ex-vivo, while the difference in FA values between tumors and normal PZ was significant only in-vivo. Paired t-test showed significant difference between in-vivo and ex-vivo FA values in tumors, but not in the normal PZ. The simulations showed that lower SNR results in an increasing overestimation of the FA values with decreasing ADC. These results suggest that the in-vivo increase in FA values in tumors is due to low SNR, rather than the presence of cancer. The results of this study suggest that FA does not contribute significantly to the diagnostic capabilities of DTI in prostate cancer.

Multiple focal nodular hyperplasia lesions of the liver associated with congenital absence of the portal vein

Congenital absence of the portal vein (CAPV) is a rare anomaly in which the intestinal and splenic venous drainage bypass the liver and drain directly into the systemic veins through various porto-systemic shunts. In this article, we illustrate a case of multiple focal nodular hyperplasia (FNH) with congenital absence of the portal vein in a male, which, to our knowledge, is the third reported case in the literature since its first description in 1793. Furthermore, we discuss the embryology of the portal vein and the Morgan and Superina classification of portosystemic anomalies, the association between portal vein agenesis and multiple FNHs, and, lastly, the use of a hepatocellular-specific MRI contrast agent as an important diagnostic tool in the confirmation of FNH.