Contrast enhancement of intracranial lesions at 1.5 T: comparison among 2D spin echo, black-blood (BB) Cube, and BB Cube-FLAIR sequences.

OBJECTIVES: The purpose of this study was to investigate the usefulness of T1W black-blood Cube (BB Cube) and T1W BB Cube fluid-attenuated inversion recovery (BB Cube-FLAIR) sequences for contrast-enhanced brain imaging, by evaluating flow-related artefacts, detectability, and contrast ratio (CR) of intracranial lesions among these sequences and T1W-SE. METHODS: Phantom studies were performed to determine the optimal parameters of BB Cube and BB Cube-FLAIR. A clinical study in 23 patients with intracranial lesions was performed to evaluate the usefulness of these two sequences for the diagnosis of intracranial lesions compared with the conventional 2D T1W-SE sequence. RESULTS: The phantom study revealed that the optimal parameters for contrast-enhanced T1W imaging were TR/TE = 500 ms/minimum in BB Cube and TR/TE/TI = 600 ms/minimum/300 ms in BB Cube-FLAIR imaging. In the clinical study, the degree of flow-related artefacts was significantly lower in BB Cube and BB Cube-FLAIR than in T1W-SE. Regarding tumour detection, BB Cube showed the best detectability; however, there were no significant differences in CR among the sequences. CONCLUSIONS: At 1.5 T, contrast-enhanced BB Cube was a better imaging sequence for detecting brain lesions than T1W-SE or BB Cube-FLAIR. KEY POINTS: • Cube is a single-slab 3D FSE imaging sequence. • We applied a black-blood (BB) imaging technique to T1W Cube. • At 1.5 T, contrast-enhanced T1W BB Cube was valuable for detecting brain lesions.

Uterine diverticulum mimicking endometriotic cyst of the ovary.

Uterine diverticulum is a rare congenital malformation caused by abnormal fusion of the Müllerian ducts. The diagnosis of uterine diverticulum is difficult, and it is often misdiagnosed as a Müllerian duct anomaly, degenerated uterine fibroid, or ovarian cyst. We herein report a case of uterine diverticulum mimicking an ovarian endometriotic cyst. A multiparous woman with a history of normal vaginal delivery underwent magnetic resonance imaging for investigation of lower abdominal pain and fever. A 155-mm cystic lesion was observed on the ventral side of the uterus. The content of the cyst showed high signal intensity on T1- and T2-weighted images with precipitates of low signal intensity on the dorsal side, suggesting an endometriotic cyst of the ovary. Surgical and pathological findings revealed that the cyst was pedunculated from the anterior uterine body and composed of 3 layers: CD10-positive endometrium, a smooth muscle layer, and serosa. A uterine diverticulum was definitively diagnosed.

Time-synchronized 2-deoxy-2-[18F]fluoro-D-glucose PET/MRI with MR-active trigger and Bayesian penalized likelihood reconstruction: Diagnostic utility for locoregional extension of endometrial cancer.

PURPOSE: Minimal misregistration of fused PET and MRI images can be achieved with simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI). However, the acquisition of multiple MRI sequences during a single PET emission scan may impair fusion precision of each sequence. This study evaluated the diagnostic utility of time-synchronized PET/MRI using an MR active trigger and a Bayesian penalized likelihood reconstruction algorithm (BPL) to assess the locoregional extension of endometrial cancer. METHODS: Fifty-five patients with endometrial cancer who underwent pelvic 2-deoxy-2-[18F]fluoro-D-glucose PET/MRI were retrospectively evaluated. The PET emission time for the BPL reconstruction was determined by the MR active trigger of each MR sequence. The concordance rates of image interpretation with pathological T-staging, diagnostic performance for deep myometrial invasion (MI), and diagnostic confidence levels were evaluated by two readers and compared between time-synchronized, overlapping (conventional and simultaneous, but not time-synchronized), and sequential (not simultaneous) PET/MRI and MRI with diffusion-weighted imaging. Misregistration of the PET/MRI-fused images was determined by evaluating the differences in bladder dimensions. RESULTS: The T classification by time-synchronized PET/MRI was the most concordant with the pathological T classification for the two readers. Time-synchronized PET/MRI had a significantly higher diagnostic performance for deep MI and higher confidence level scores than overlapping PET/MRI for the novice reader (p = 0.033 and p = 0.038, respectively). The differences in bladder dimension on sequential PET/MRI were significantly larger than those on overlapping and time-synchronized PET/MRI (p <0.001). CONCLUSION: Time-synchronized PET/MRI is superior to conventional PET/MRI for assessing the locoregional extension of endometrial cancer.

Endometrial cancer: preoperative staging using three-dimensional T2-weighted turbo spin-echo and diffusion-weighted MR imaging at 3.0 T: a prospective comparative study.

OBJECTIVES: To prospectively assess the efficacy of 3-T magnetic resonance (MR) imaging using the three-dimensional turbo spin-echo T2-weighted and diffusion-weighted technique (3D-TSE/DW) compared with that of conventional imaging using the two-dimensional turbo spin-echo T2-weighted and dynamic contrast-enhanced technique (2D-TSE/DCE) for the preoperative staging of endometrial cancer, with pathological analysis as the reference standard. METHODS: Seventy-one women with endometrial cancer underwent MR imaging using 3D-TSE/DW (b = 1,000 s/mm(2)) and 2D-TSE/DCE. Two radiologists independently assessed the two imaging sets. Accuracy, sensitivity, and specificity for staging were analysed with the McNemar test; the areas under the receiver operating characteristic curve (Az) were compared with a univariate z-score test. RESULTS: The results for assessing deep myometrial invasion, accuracy, sensitivity, specificity and Az, respectively, were as follows: 3D-TSE/DW-observer 1, 87 %, 95 %, 85 % and 0.96; observer 2, 92 %, 84 %, 94 % and 0.95; 2D-TSE/DCE-observer 1, 80 %, 79 %, 81 % and 0.89; observer 2, 86 %, 84 %, 87 % and 0.86. Most of the values were higher with 3D-TSE/DW without significant differences (P > 0.12). For assessing cervical stromal invasion, there were no significant differences in those values for both observers (P > 0.6). CONCLUSIONS: Accuracy of 3D-TSE/DW was at least equivalent to that of the conventional technique for the preoperative assessment of endometrial cancer. KEY POINTS: • New techniques in MR imaging help assess patients with endometrial cancer. • A 3D T2-weighted TSE sequence seems equally as accurate as conventional techniques. • Three-dimensional TSE/DW imaging does not require intravenous contrast material and is relatively quick. • Tumour extent of endometrial cancer can be clearly shown on diffusion-weighted images. • Junctional zone can be visualised well on 3D-TSE T2-weighted images.

T2* relaxometry mapping of the uterine zones.

BACKGROUND: Previous literature demonstrated that the T2* value of the uterine junctional zone was lower than that of peripheral myometrium by using BOLD MR imaging. We expect T2* mapping image may add more information to T2-weighted images of the uterine myometrium. PURPOSE: To evaluate whether T2* mapping software would reproduce the result of previous report, and to apply the software to benign uterine diseases. MATERIAL AND METHODS: Five healthy volunteers and 19 patients clinically suspected of having benign pelvic disease were imaged using a 1.5T MR system. All women were of reproductive age, and all provided informed consent. Sagittal T2* images using a multishot EPI sequence were obtained. T2* values were calculated and color T2* maps reconstructed using a T2* fitting tool. RESULTS: The uterine zones could be identified in all 24 examinations on the T2* maps. In addition, a thin "4th zone" was seen between the endometrium and the JZ (junctional zone) in 19 of 24 examinations. The T2* value of JZ was significantly lower than that of peripheral myometrium (PM) (P < 0.001). No significant difference in the T2* value of the JZ or of PM was noted between normal uterus and uterus with leiomyomas and/or adenomyosis. CONCLUSION: A quantitative T2* map can easily be obtained using the PRIDE software T2* fitting tool, and the software reproduces the result from previous report. T2* value of the junctional zone was lower than that of peripheral myometrium regardless of having benign myometrial diseases.

Primary adenomyoma of the fallopian tube mimicking tubal malignant tumor.

We report a rare case of adenomyoma localized only in the left fallopian tube mimicking tubal malignant tumor. A 45-year-old woman presented with mild pelvic pain, dysmenorrhea and left adnexal mass. Magnetic resonance imaging showed a solid tumor, suspected primary cancer of the fallopian tube, and serum carbohydrate antigen 125 was elevated to 72 U/mL (normal; 0-35). At surgery, the tumor was revealed as a left fallopian tube tumor without torsion. Postoperative histopathology showed that the tumor included bundle-like growing non-atypical leiomyoma cells and ectopic normal endometrium accompanied with endometrial stroma and we diagnosed primary adenomyoma of the left fallopian tube. Adenomyoma localized only in the fallopian tube is a rare entity and it can occur only in the fallopian tube.

Carcinomatous meningitis during systematic chemotherapy in a patient with advanced small-cell neuroendocrine carcinoma of the uterine cervix.

Carcinoma meningitis with uterine cervical cancer is an extremely rare event. We present the clinicopathologic characteristics and diagnostic imaging findings of a patient with advanced small-cell neuroendocrine carcinoma of the cervix who had developed carcinoma meningitis during systematic chemotherapy.

Optimal scanning protocol of arterial dominant phase for hypervascular hepatocellular carcinoma with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced MR.

PURPOSE: To investigate optimal delay time of hepatic arterial phase in Gadoxetate-enhanced MR for detecting hypervascular hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-five patients with 85 hypervascular HCCs and 9 patients with 16 hypervascular HCCs underwent Gadoxetate- and Gd-DTPA-enhanced MR at 1.5 Tesla (T) system, respectively. All HCCs were analyzed 10-38 s after injection using a time-resolved dynamic MR sequence with keyhole data sampling. Seven sequential phase images (1 phase = 4 s) were obtained during a single breath hold of 28 s. Time-intensity curves of the abdominal aorta, liver parenchyma, and HCC were obtained, then aortic contrast arrival time, time of peak HCC enhancement, duration time of HCC and aortic enhancement, and time delay from aortic contrast arrival to peak enhancement of HCC were measured. RESULTS: Aortic contrast arrival time was 15.1 ± 2.9 s, time of peak HCC enhancement 29.9 ± 4.6 s, duration time of HCC enhancement 17.4 ± 6.4 s postinjection of Gadoxetate. Duration of aortic enhancement (23.6 ± 3.5 s) of Gadoxetate-enhanced MR was significantly less than that of Gd-DTPA-enhanced MR (26.3 ± 2.8 s) (P < 0.0059). CONCLUSION: Peak enhancement time of HCC on Gadoxetate-enhanced MR imaging occurred at 14.6 ± 4.6 s after aortic contrast arrival.

Unenhanced fat fraction ratios obtained by MR and enhanced T2* values with liver-specific MR contrast agents for diagnosis of non-alcoholic steatohepatitis in rats.

BACKGROUND: Non-invasive MR imaging is expected to be used for accurate diagnosis and quantification of non-alcoholic steatohepatitis (NASH), because NASH is a progressive fatty liver disease. New MR techniques, such as fat fraction ratio (FFR) and T2* value measurement, have attracted an increasing attention, because those techniques can measure quantitative parameters of fibrosis, fat and iron deposition in the liver. PURPOSE: To investigate the potential of FFR and T2* value in NASH with pre-enhancement, gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) or super-paramagnetic iron oxide (SPIO)-enhanced MRI. MATERIAL AND METHODS: Twenty-eight rats were divided equally into four groups (one control group and three NASH groups). All rats underwent unenhanced, Gd-EOB-DTPA, and SPIO-enhanced MRI. The T2* value of the liver was measured for each image sequence, and then changes in T2* values before and after each injection were analyzed using Dunnett's test. The reduction rate of T2* value before and 13 min after injection of Gd-EOB-DTPA or SPIO was analyzed using Mann-Whitney's U test. Moreover, FFR of the liver was measured before enhancement, and the relationship between fat fraction and the calculated fat area percentage on a pathological specimen was examined using Spearman's correlation test. RESULTS: On pre-enhancement, FFR and T2* value were 26.0% ± 12.0% and 21.5 ± 4.2 ms for all NASH groups, and 0.9% ± 0.5% and 30.8 ±-5.5 ms for control, respectively. Both FFR and T2* values were significantly different between the NASH and control groups. The reduction rate of T2* value was significantly lower in the NASH groups than in the control group on SPIO-enhanced MRI, though there was no significant difference on Gd-EOB-DTPA-enhanced MRI. FFR was correlated with the calculated fat area percentage for the pathological specimen. CONCLUSION: Pre-enhancement FFR, T2* value measurement and reduction rate of T2* value on SPIO-enhanced MRI may help estimate the progress of liver fat deposition and fibrosis in NASH.

Uterine cervical carcinoma: preoperative staging with 3.0-T MR imaging--comparison with 1.5-T MR imaging.

PURPOSE: To prospectively evaluate the efficacy of 3.0-T magnetic resonance (MR) imaging in the preoperative staging of cervical carcinoma compared with that at 1.5-T imaging, with surgery and pathologic analysis as the reference standards. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Thirty-one consecutive patients (age range, 27-71 years; mean age, 51.1 years) underwent 3.0- and 1.5-T MR imaging. Quantitative and qualitative analyses were performed. Two radiologists independently evaluated images in terms of local-regional staging. MR findings were compared with surgicopathologic findings. RESULTS: Mean tumor signal-to-noise ratios, mean cervical stroma signal-to-noise ratios, and mean tumor-to-cervical stroma contrast-to-noise ratios at 3.0-T imaging were significantly higher than those at 1.5-T imaging (P = 9.1 x 10(-6), P = 1.8 x 10(-6), and P = .008, respectively). Image homogeneity at 3.0-T imaging was significantly inferior to that at 1.5-T imaging (P = .005). There were no significant differences in terms of the degree of susceptibility artifacts. Interobserver agreement between the two radiologists for local-regional staging was good or excellent (kappa = 0.65-0.89). Sensitivity, specificity, and area under the receiver operating characteristic curve for radiologist 1 in the evaluation of parametrial invasion were (a) 75% for both 3.0- and 1.5-T imaging, (b) 70% for both 3.0- and 1.5-T imaging, and (c) 0.82 for 3.0-T imaging and 0.85 for 1.5-T imaging, respectively. Corresponding values for vaginal invasion were (a) 67% for both 3.0- and 1.5-T imaging, (b) 68% for 3.0-T imaging and 72% for 1.5-T imaging, and (c) 0.62 for 3.0-T imaging and 0.67 for 1.5-T imaging, respectively. Corresponding values for lymph node metastases were (a) 57% for both 3.0- and 1.5-T imaging, (b) 83% for 3.0-T imaging and 88% for 1.5-T imaging, and (c) 0.72 for 3.0-T imaging and 0.78 for 1.5-T imaging, respectively. Neither radiologist noted significant differences between values obtained with 3.0-T imaging and those obtained with 1.5-T imaging (P > .5 for all comparison pairs). CONCLUSION: In this study, 3.0-T MR imaging was characterized by high diagnostic accuracy in the presurgical evaluation of patients with cervical carcinoma, although 3.0-T imaging was not significantly superior to 1.5-T imaging.

Ring-shaped lateral ventricular nodules: an incidental finding on brain magnetic resonance imaging.

INTRODUCTION: We have occasionally seen ring-shaped lateral ventricular nodules <1 cm in diameter during routine brain magnetic resonance imaging (MRI). We investigated retrospectively clinical and MRI findings of the nodules. MATERIALS AND METHODS: Review of radiological records was performed for 39,607 patients who underwent brain MRI between January 2001 and April 2008. Nodules were assessed for number, location, shape, and signal intensity, which was determined based on the range of signal intensity from gray to white matter on T1- and T2-weighted imaging. Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI), contrast enhancement characteristics, and serial MRI changes of nodules were assessed when available. RESULTS: Nine of 39,607 patients (0.023%) showed the nodules. No symptoms associated with the nodules. Among the nine patients, 11 nodules were identified (one nodule in seven patients (77.8%) and two nodules in two patients (22.2%)). Location was limited to the roof of the body for six nodules (54.5%) and the frontal horn for five patients (45.5%). All nodules (100%) were round and isointense on T1- and T2-weighted imaging. On FLAIR imaging of eight nodules, six (75%) were hyperintense, and two (25%) were isointense. On DWI of seven nodules, all nodules (100%) were isointense. None of seven nodules (0%) examined using postcontrast MRI showed enhancement. None of eight nodules (0%) examined using serial MRI (range, 4-60 months) showed changes in morphology over time. CONCLUSION: These nodules were incidentally encountered and shared similar MRI features. Although pathological confirmation was lacking in our cases, these nodules may be of nonaggressive nature.

Adrenal masses: the value of additional fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) in differentiating between benign and malignant lesions.

OBJECTIVE: To investigate whether integrated fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) can differentiate benign from adrenal malignant lesions on the basis of maximum standardized uptake value (SUV(max)), tumor/liver (T/L) SUV(max) ratio, and CT attenuation value (Hounsfield Units; HU) of unenhanced CT obtained from FDG-PET/CT data. METHODS: We studied 30 patients with 35 adrenal lesions (16 adrenal benign lesions, size 16 +/- 5 mm, in 15 patients; and 19 adrenal malignant lesions, 24 +/- 12 mm, in 15 patients) who had confirmed primary malignancies (lung cancer in 23 patients, lymphoma in 2, esophageal cancer in 2, hypopharyngeal cancer in 1, prostate cancer in 1, and 1 patient in whom lesions were detected at cancer screening). All patients underwent PET/CT at 1 h post FDG injection. Diagnosis of adrenal malignant lesions was based on interval growth or reduction after chemotherapy. An adrenal mass that remained unchanged for over 1 year was the standard used to diagnose adrenal benign lesions. Values of FDG uptake and CT attenuation were measured by placing volumetric regions of interest over PET/CT images. Adrenal uptake of SUV(max) >/= 2.5 was considered to indicate a malignant lesion; SUV(max) < 2.5 was considered to indicate a benign lesion. In further analysis, 1.8 was employed as the threshold for the T/L SUV(max) ratio. Unenhanced CT obtained from PET/CT data was considered positive for adrenal malignant lesions based on a CT attenuation value >/= 10 HU; lesions with a value < 10 HU were considered adrenal benign lesions. Mann-Whitney's U test was used for statistical analyses. RESULTS: SUV(max) in adrenal malignant lesions (7.4 +/- 3.5) was higher than that in adrenal benign lesions (2.1 +/- 0.5, p < 0.05). The CT attenuation value of adrenal malignant lesions (27.6 +/- 11.9 HU) was higher than that of adrenal benign lesions (10.1 +/- 12.3 HU, p < 0.05). In differentiating between adrenal benign and malignant lesions, a CT threshold of 10 HU corresponded to a sensitivity of 57%, specificity of 94%, accuracy of 74%, positive predictive value of 92% and negative predictive value of 65%. An SUV(max) cut-off value of 2.5 corresponded to a sensitivity of 89%, specificity of 94%, accuracy of 91%, positive predictive value of 94% and negative predictive value of 88%. The T/L SUV(max) ratio was 1.0 +/- 0.2 for adrenal benign lesions and 4.5 +/- 3.0 for adrenal malignant lesions. And T/L SUV(max) ratio cut-off value of 1.8 corresponded to a sensitivity of 85%, specificity of 100%, accuracy of 91%, positive predictive value of 100% and negative predictive value of 83%. CONCLUSIONS: FDG-PET/CT with additional SUV(max) analysis improves the diagnostic accuracy of adrenal lesions in cancer patients.

Comparison between one-route and two-route injection for liver and aortic enhancement using MDCT.

OBJECTIVE: The purpose of our study was to evaluate whether simultaneous injection into cubital veins bilaterally at one half of the standard injection rate achieves similar hepatic and aortic enhancement on MDCT as the conventional injection rate into a single cubital vein. MATERIALS AND METHODS: Thirty-two patients underwent multiphase MDCT because they were suspected of having a hepatic tumor. Patients were assigned to one of the following two groups: group A, 100 mL of 370 mg I/mL of contrast medium injected into a unilateral cubital vein (one-route) via a 20-gauge cannula at a rate of 4 mL/s; or group B, 50 mL of contrast medium injected into the cubital veins bilaterally (two-route) via 24-gauge cannulas at 2 mL/s. Peak contrast enhancement of the liver and abdominal aorta for groups A and B was measured using regions of interest and compared; arrival time of the contrast media was also compared using a bolus-tracking system. Analysis was performed using Wilcoxon's signed rank test. RESULTS: Peak aortic enhancement of groups A and B was 367 +/- 67 H and 361 +/- 113 H (p = 0.61, not significant), respectively, and peak hepatic enhancement of groups A and B was 56 +/- 11 H and 56 +/- 16 H (p = 0.88, not significant), respectively. Mean arrival time to the aorta of group B (19.4 +/- 3.4 seconds) was significantly later compared with that of group A (15.5 +/- 3.5 seconds) (p = 0.005). CONCLUSION: The slower two-route injection produced the same aortic and hepatic enhancement as the faster one-route method with faster injection, but the arrival time of the contrast medium was later using the two-route method.

Discordance of motion artifacts on magnetic resonance imaging in Creutzfeldt-Jakob disease: comparison of diffusion-weighted and conventional imaging sequences.

PURPOSE: Motion artifact is problematic in the diagnosis of Creutzfeldt-Jakob disease (CJD) because of dementia. The purpose was to compare the occurrence of this artifact between a diffusion-weighted (DW) magnetic resonance (MR) imaging sequence and conventional sequences. MATERIALS AND METHODS: Ten MR examinations comprising T2-weighted, T1-weighted, DW, and fluid-attenuated inversion recovery imaging in seven CJD patients were retrospectively evaluated. The occurrence of motion artifacts on each sequence were assessed, and the examination was classified into four groups as follows: group A, motion artifact not revealed on DW imaging but revealed on one or more other sequences; group B, revealed on DW imaging and one or more other sequences; group C, not revealed on any sequences; and group D, revealed on DW imaging but not on any other sequences. RESULTS: The 10 MR examinations were classified as eight group A (80%), one B (10%), one C (10%), and zero D (0%). CONCLUSION: Motion artifacts are likely to occur in any conventional imaging sequences in CJD, but the fast-imaging ability of DW imaging can reduce this artifact. The combination of an absence of motion artifact on DW imaging and the presence on conventional sequences may be one of the frequent findings of CJD.

T2*-sensitized high-resolution magnetic resonance venography using 3D-PRESTO technique.

PURPOSE: We evaluated the ability of the PRESTO (principles of echo shifting with a train of observations) technique to reveal small veins and microbleeds in the human brain. MATERIALS AND METHODS: In an experimental study, we calculated contrast-to-noise ratio (CNR) between a cerebral parenchymal phantom and human venous blood using 3 sequences of 3-dimensional (3D)-PRESTO, 3D-gradient recalled echo (GRE), and 3D-GRE echo-planar imaging (EPI). Then, we examined 7 healthy volunteers and 5 patients with venous angiomas or traumatic brain injuries using the 3D-PRESTO technique. In volunteer studies, MR venographies were reconstructed from 10-mm, 15-mm, and 20-mm thickness data using the minimum-intensity-projection (MinIP) technique. Three radiologists identified deep brain venous anatomy and counted the visible left medullary veins. In clinical studies, we evaluated the lesion conspicuity of small venous diseases and microbleeds. RESULTS: In the phantom study, 3D-PRESTO showed the highest CNR. In all volunteer studies, the deep brain venous anatomy was readily identified in the MinIP images at each thickness. The mean numbers of counted left medullary veins were 5.1 for 10 mm, 5.9 for 15 mm, and 6.7 for 20 mm in the MinIP images. The difference was significant between 10-mm and 20-mm MinIP images (P=0.02). In patient studies, abnormal small veins and microbleeds were clearly revealed. CONCLUSION: High-resolution MR venography using 3D-PRESTO technique can clearly depict small veins and microbleeds in the human brain.

[Advancement of the imaging for hepatic malignancies].

The development of CT and MR imaging technology represents a significant advancement. On CT imaging,the advent of multi-detector row CT (MDCT) scanners enables an increase in both scanning speed and spatial resolution. Multiphasic dynamic study is useful for the detection of hepatocellular carcinomas (HCCs) which are demonstrated as hyperattenuated lesions during the hepatic arterial phase. Many investigators assess the optimal timing for detection of HCCs by using the evolving MDCT, and have demonstrated the high detection rate for HCCs. Thanks to the increase in spatial resolution along the z-axis,we are now able to generate high-quality CT angiography and multiplanar reformations without complicated interpolation steps. These CT angiography and MPR images of patients with malignant hepatic tumors (e.g., HCCs, cholangiocellular carcinomas) are very useful for preoperative evaluation. On the other hand, the development of MR fast imaging techniques allows rapid breath-hold, whole-liver imaging. Superparamagnetic iron oxide (SPIO) is a liver-specific particulate magnetic resonance (MR) imaging contrast agent that is taken up by the reticuloendothelial system of the liver. SPIOenhanced MR imaging is useful for the detection of hepatic metastases. The advent of parallel imaging techniques improves the quality of images obtained with diffusion weighted (DW) imaging of the liver. DW imaging demonstrates high accuracy in the detection of hepatic metastases. Recently, in Japan, positron emission tomography (PET)-CT has also been employed for evaluation of hepatic metastases.

Magnetic resonance elastography in the assessment of hepatic fibrosis: a study comparing transient elastography and histological data in the same patients.

PURPOSE: To evaluate the quantitative measurement of liver stiffness (LS), compare the diagnostic performance of magnetic resonance elastography (MRE) and ultrasound-based transient elastography (TE), and evaluate two different MRE-based LS measurement methods. METHODS: Between October 2013 and January 2015, 116 consecutive patients with chronic liver disease underwent MRE to measure LS (kilopascals; kPa). Of the 116 patients, 51 patients underwent both TE and liver biopsy, and the interval between the liver biopsy and both the MRE and TE was less than 90 days. MRE-derived LS values were measured on the anterior segment of the right lobe (single small round regions of interest per slice; srROIs) and whole right lobe of the liver (free hand region of interest; fhROI), and these values were correlated with pathological fibrosis grades and diagnostic performance. RESULTS: Pathological fibrosis stage was significantly correlated with srROIs (r = 0.87, p < 0.001), fhROI (r = 0.80, p < 0.001), and TE (r = 0.73, p < 0.001). For detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis, the area under the curve (AUC) associated with the srROIs was largest, and there was a significant difference between srROIs and TE (0.93 vs. 0.82, p = 0.006), srROIs and fhROI (0.93 vs. 0.89, p = 0.04) for detection of ≥F2. For advanced fibrosis and cirrhosis detection, AUCs were not significant (0.92-0.96). CONCLUSIONS: MRE and TE detected liver fibrosis with comparable accuracy. In particular, the srROIs method was effective for detecting of significant fibrosis.

Developing an MR imaging strategy for diagnosis of ovarian masses.

Magnetic resonance (MR) imaging provides useful information for characterization of various ovarian masses as neoplastic or nonneoplastic and, when neoplastic, on a spectrum from benign to malignant. The use of MR imaging for diagnosis of ovarian masses includes consideration of morphologic characteristics and signal intensity characteristics on T1- and T2-weighted images. The morphologic characteristics of cystic masses, cystic and solid masses, and predominantly solid masses provide important information. In general, cystic masses represent benign tumors, whereas cystic and solid masses are strongly associated with malignancy. Predominantly solid masses include benign, borderline malignant, and malignant tumors. T1-weighted images provide useful information for characterization because hemorrhagic adnexal masses (eg, endometriotic cyst) and cystic teratomas can be correctly diagnosed when the mass has high signal intensity. Significant low signal intensity in solid masses on T2-weighted images is indicative of fibrothecomas and Brenner tumors because extensive fibrous tissue produces significant low signal intensity on T2-weighted images. A strategy for diagnosis of ovarian masses with MR imaging incorporates signal intensity characteristics into morphologic characteristics.

Imaging of metastases from breast cancer to uncommon sites: a pictorial review.

There are three types of breast cancer recurrence which can occur after initial treatment: local, regional, and distant. Distant metastases are more frequent than local and regional recurrences. It usually occurs several years after the primary breast cancer, although it is sometimes diagnosed at the same time as the primary breast cancer. Although the common distant metastases are bone, lung and liver, breast cancer has the potential to metastasize to almost any region of the body. Early detection and treatment of distant metastases improves the prognosis, therefore radiologists and clinicians should recognize the possibility of metastasis from breast cancer and grasp the imaging characteristics. In this report, we demonstrate the imaging characteristics of metastases from breast cancer to uncommon sites.

MR imaging of disorders associated with female infertility: use in diagnosis, treatment, and management.

Magnetic resonance (MR) imaging has extended the usefulness of imaging in evaluation of pelvic disorders associated with female infertility. The causes of female infertility include ovulatory disorders (ie, pituitary adenoma and polycystic ovarian syndrome), disorders of the fallopian tubes (ie, hydrosalpinx and pelvic inflammatory disease), uterine disorders (ie, müllerian duct anomaly, adenomyosis, and leiomyoma), and pelvic endometriosis. Although laparoscopy, hysteroscopy, hysterosalpingography, and transvaginal ultrasonography are the most effective techniques for evaluation of pelvic disorders related to female infertility, MR imaging is used in a variety of clinical settings in diagnosis, treatment, and management. The applications of MR imaging include evaluation of the functioning uterus and ovaries, visualization of pituitary adenomas, differentiation of müllerian duct anomalies, and accurate noninvasive diagnosis of adenomyosis, leiomyoma, and endometriosis. In addition, MR imaging helps predict the outcome of conservative treatment for adenomyosis, leiomyoma, and endometriosis and may lead to selection of better treatment plans and management. Finally, MR imaging may serve as an adjunct to diagnostic laparoscopy and hysterosalpingography in patients with hydrosalpinx, peritubal adhesions, or pelvic adhesions related to endometriosis.