Satoru Kitano

Diagnostic usefulness of endorectal magnetic resonance imaging with dynamic contrast-enhancement in patients with localized prostate cancer: mapping studies with biopsy specimens.

Background : New diagnostic criteria for dynamic magnetic resonance (MR) imaging in prostate cancer are presented. The diagnostic usefulness of endorectal MR imaging with dynamic contrast‐enhancement in localized prostate cancer and the validity of these criteria were evaluated.

Ectopic pregnancy: MRI findings and clinical utility

PurposeTo assess the utility of magnetic resonance imaging (MRI) in patients with clinically suspected ectopic pregnancy (EP).MethodsWe retrospectively reviewed MRIs of 26 consecutive patients who were clinically suspected of having an EP. The diagnostic utility of MRI features of EP was analyzed retrospectively as follows: (1) Direct sign detection of ectopic gestational sac (GS); (2) Indirect signs tubal dilatation with hemosalpinx, adnexal hematoma, and hemorrhagic ascites. The diagnostic accuracy of each sign and their combination was compared to surgical records. The MRI findings of an ectopic GS were reviewed as follows: size, shape, signal intensity, and enhancement pattern.ResultsOf 26 patients, 24 had a tubal pregnancy; 22 of these 24 patients (92%) had a direct sign (sensitivity: 91.3%; specificity: 100%; positive predictive value: 100%). The diagnostic accuracy of the direct sign was 92%; this was more accurate than that of any single indirect sign (39%, 54%, and 50%, respectively). However, the diagnostic accuracy of EP increased to 100% when diagnostic criteria required the presence of a direct sign or at least two indirect signs.ConclusionsMRI is an effective modality for diagnosing EP with a high detection rate of extrauterine GSs. The combination of direct and indirect signs is useful for establishing the correct diagnosis.

Preliminary experience with superparamagnetic iron oxide-enhanced dynamic magnetic resonance imaging and comparison with contrast-enhanced computed tomography in endoleak detection after endovascular aneurysm repair

OBJECTIVE Contrast-enhanced computed tomography (CE-CT) has been commonly used for follow-up imaging after endovascular aneurysm repair (EVAR), but it is difficult to use on patients with renal insufficiency. Superparamagnetic iron oxide (SPIO) particles, contrast medium for magnetic resonance imaging (MRI) that has been widely used for detection of the liver tumor, rarely affects renal function. The present study examined SPIO-enhanced dynamic MRI as a potential alternative to CE-CT for detection of endoleaks after EVAR. METHODS Institutional review board approval was obtained for this prospective study. Twenty-three consecutive patients with normal renal function were evaluated using both CE-CT and SPIO-enhanced MRI within 2 weeks after EVAR. The median interval between the two modalities was 2 days. SPIO-enhanced MRI was performed at 1.5 T with T1-weighted, SPIO-enhanced dynamic, and postcontrast T1-weighted gradient echo sequences. The CE-CT protocol consisted of triple scans. Two experienced, blinded observers evaluated all images. Consensus reading of CE-CT and SPIO-MRI was defined as the reference standard. Interobserver, intraobserver, and intermodality agreement for endoleak detection was assessed by κ statistics. RESULTS A total of 11 type II endoleaks originating from either the lumbar or inferior mesenteric artery were detected. Eight were able to be detected by CE-CT (8/11:73%) and 10 (10/11:91%) by SPIO-enhanced MRI. Interobserver (κ = 0.91; 95% CI, 0.74-1.00) and intraobserver agreement for MRI (κ = 1.00) were excellent. Intermodality agreement for endoleak detection was moderate (κ = 0.63; 95% CI, 0.32-0.94; and κ = 0.62; 95% CI, 0.29-0.95 for observers A and B, respectively). CONCLUSIONS SPIO-enhanced MRI could represent a useful alternative to CE-CT, as it offers excellent interobserver, intraobserver agreement, and could detect more endoleaks than CE-CT.

Long-Term Palliative Treatment of Hepatocellular Carcinoma Extending into the Portal Vein and Bile Duct by Chemoembolization and Metallic Stenting

Abstract We present a patient with hepatocellular carcinoma accompanied by portal vein and bile duct tumor thrombi. The patient was treated with a spiral Z-stent covered by a polyethylene sheet placed in the bile duct, a Wallstent placed in the portal vein, chemoembolization, and external radiation therapy. The patient is alive with patency of both endoprostheses 18 months later.

“Sukeroku sign” and “dent internal-capsule sign”—identification guide for targeting the subthalamic nucleus for placement of deep brain stimulation electrodes

IntroductionThe purpose of this study was to assess the usefulness of signs (“Sukeroku sign” and “dent internal-capsule sign”) for the recognition of subthalamic nucleus (STN).Materials and methodsFive Parkinson’s disease cases in which there was a successful placement of deep brain stimulation (DBS) electrodes at the STN were retrospectively reviewed. Five radiologists who were not engaged in localization of STNs in clinical practice were asked to locate the STNs before and after instructions on the signs. We evaluated the deviation between the reader-located points and the location of the DBS electrode for which there had been a successful installation.ResultsAfter instruction, there was a significant reduction in the deviation between the reader-located points and the DBS electrode. The time required for localization was also reduced after the instructions.ConclusionSukeroku sign and dent internal-capsule sign are feasible indicators of STN and seem to be useful in helping to identify the STN.

Polypoid endometriosis of the ureter mimicking fibroepithelial polyps

We present a case of polypoid endometriosis of the ureter that showed bilateral polypoid intraluminal masses in the lower part of the ureter mimicking ureteral fibroepithelial polyps, arising with a background of pelvic endometriosis and a history of gonadotropin releasing hormone (GnRH) therapy. Magnetic resonance imaging revealed the masses to have high signal intensity on T2-weighted imaging. The location and bilaterality of the polypoid intraluminal masses are considered useful points in the differential diagnosis of fibroepithelial polyps.

Prominent signal intensity of T1/T2 prolongation in subcortical white matter of the anterior temporal region on conventional screening MRI of late preterm infants with normal development

PURPOSE This study discusses prominent signal intensity of T(1)/T(2) prolongation of subcortical white matter within the anterior temporal region in premature infant brains that radiologists may encounter when interpreting conventional screening MRIs. MATERIALS AND METHODS T(1)- and T(2)-weighted images of 69 preterm and term infants with no neurological abnormalities or developmental delays were evaluated retrospectively for areas of prominent signal intensity of T(1)/T(2) prolongation in white matter. We measured signal intensities of anterior temporal white matter, deep temporal white matter, frontopolar white matter and subcortical white matter of the precentral gyrus. We accessed chronological changes in signal intensity in the anterior and deep temporal white matter. We also analyzed variance tests among the signal intensity ratios to the ipsilateral thalamus of white matter areas by gestational age. RESULTS There was high frequency of prominent signal intensity of T(1)/T(2) prolongation in the temporal tip, particularly at a gestational age of 36-38 weeks. Signal intensity ratio of the anterior temporal white matter was lower on T(1)-weighted images and higher on T(2)-weighted images, and the finding became less prominent with increasing gestational age. The signal intensity ratios of anterior temporal white matter at a gestational age of 36-37 weeks and 38-39 weeks were significantly different from other regions. CONCLUSION Prominent signal intensity of T(1)/T(2) prolongation of subcortical white matter of the anterior temporal region is seen in normal premature infants, especially those at 36-39 gestational weeks. Although it is a prominent finding, radiologists should understand that these findings do not represent a pathological condition.