Nagaaki Marugami

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.

“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.

Integrative Assessment of Pretreatment Inflammation-, Nutrition-, and Muscle-Based Prognostic Markers in Patients with Muscle-Invasive Bladder Cancer Undergoing Radical Cystectomy

Objective: The present study evaluated the clinical relevance of an integrative preoperative assessment of inflammation-, nutrition-, and muscle-based markers for patients with muscle-invasive bladder cancer (MIBC) undergoing curative radical cystectomy (RC). Methods: The analysis enrolled 117 patients and the variables included age, body mass index (BMI), neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio, modified Glasgow Prognostic Score (mGPS), prognostic nutritional index (PNI), Controlling Nutritional Status score, psoas muscle index (PMI), and peak expiratory flow (PEF). The correlations among the variables were evaluated and their prognostic values after RC were tested. Results: Three inflammation markers (ratios of blood cell counts) were positively correlated (p < 0.0001). The PNI and the BMI were positively correlated (p = 0.04), although they were inversely correlated with the three inflammation markers (p < 0.0001). Age was not significantly correlated with the inflammation markers and PMI, although older age was associated with lower PNI and lower PEF. The disease-specific survival was independently predicted by T4 tumor, positive N status, and decreased PNI. Overall survival was independently predicted by T4 tumor, mGPS, and pretreatment sarcopenia status. Conclusions: The inflammation-, nutrition-, and muscle-based markers would be useful risk assessment tools for MIBC.

Isolated fat-containing pancreatic metastasis from hepatocellular carcinoma

We report a case of a 50-year-old male with isolated pancreatic metastasis from hepatocellular carcinoma (HCC), in which chemical shift magnetic resonance imaging detected the presence of fat, and which mimicked fatty replacement. A solitary metastatic pancreatic tumor originating from HCC is very rare. Furthermore, we believe that this is the first report of fat-containing pancreatic metastasis from HCC.

MRI Findings of Inverted Urothelial Papilloma of the Bladder

OBJECTIVE The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder. MATERIALS AND METHODS Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images. RESULTS The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%). CONCLUSION On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.

Ultrasound follow-up of infantile hypertrophic pyloric stenosis (IHPS) during conservative therapy: ultrasound findings as criteria for diagnosis and cure

PurposeDuring conservative therapy of infantile hypertrophic pyloric stenosis (IHPS) with atropine sulfate, there are many patients who do not achieve normal values of pyloric wall thickness and canal length even though they are clinically cured (vomiting has ceased); an objective criterion for cure has not yet been established. The aim of this study was to examine whether the appearance of pyloric wall stratification can be used as a criterion for cure.MethodsTwenty infants with IHPS who were treated conservatively were enrolled. Two of them ultimately required surgery. Ultrasound examinations were done serially and the pyloric wall thickness and canal length were measured. The echogenicity of the pyloric wall and the presence of wall stratification were noted.ResultsOn admission, all infants satisfied the ultrasound criteria for IHPS and had a heterogeneous pyloric wall without stratification. With conservative therapy, symptoms disappeared, the pyloric wall thickness and the canal length gradually decreased, the echogenicity gradually became homogeneous and hypoechoic, and wall stratification appeared (in most cases before the pyloric wall thickness and the canal length had normalized). The absence of wall stratification suggests that cellular interstitial changes, such as edema or inflammation, are present in the pyloric wall in the acute stage.ConclusionPyloric wall stratification was absent during the acute stage, but it appeared after initiation of treatment but before the pyloric wall thickness and the canal length had normalized. The presence of pyloric wall stratification can be used as a criterion for cure; the absence of wall stratification can be added to ultrasound diagnostic criteria for IHPS.

Uterine endometrial carcinoma with DNA mismatch repair deficiency: magnetic resonance imaging findings and clinical features

PurposeThe purpose of this study was to identify the magnetic resonance imaging (MRI) features of uterine endometrial carcinoma (EC) with DNA mismatch repair (MMR) deficiency.Materials and methodsThis was a retrospective study approved by our institutional review board. The study included 118 patients pathologically diagnosed as having EC in our institution from April 2014 to December 2016. Of 118 patients, 8 were excluded because of insufficient data. Immunohistochemical analysis of MMR was performed retrospectively to observe the expressions of MLH1, MSH2, MSH6, and PMS2. A tumor with MMR deficiency was detected in 17 of 110 cases (15%). Clinical background characteristics and MRI findings were reviewed. These findings were compared between MMR deficiency group and the other group as a control group. Statistical significance was determined using the Fisher’s exact test and the Mann–Whitney U test, as appropriate.ResultsThe clinical background characteristics of patients with EC with MMR deficiency were not significantly different from those of other patients. On MRI, the tumor was significantly more often located in the lower uterine site (MMR(−) vs. MMR(+): 29.4 vs. 8.9% [p = 0.0366]).ConclusionEC with MMR deficiency tends to be located lower in the uterus, though most other findings were not significantly different from those of EC without MMR deficiency.