A case of atypical meningioma presenting spontaneous infarction: the findings of magnetic resonance imaging, including amide proton transfer-chemical exchange saturation transfer imaging.

We report the MRI findings of a patient with an atypical meningioma who presented with spontaneous infarction. A 67-year-old man with histories of recurrent meningioma complained of left ocular protrusion and a subsequent biopsy revealed atypical meningioma. Contrast-enhanced CT showed a uniformly enhancing tumour in the left ethmoid sinus, but MRI 2 days later showed no enhancement on Gd-T1WI and severe diffusion restriction on DWI, indicating spontaneous infarction. APT-CEST imaging showed slight hypointensity in comparison to the normal brain with a mean MTR asymmetry value of 0.48%. Tumour regrowth was confirmed on MRI after 2 months. The recurrent tumour showed moderate diffusion restriction on DWI and hyperintensity with a mean MTR asymmetry value of 2.59% on APT-CEST imaging. The decreased signal on APT-CEST at the time of spontaneous infarction may have been attributed to intratumoral acidosis and loss of viable tumour. APT-CEST imaging is useful for evaluating the intratumoral condition and tumour viability of the infarcted or ischemic tumour.

Breath-hold High-resolution T1-weighted Gradient Echo Liver MR Imaging with Compressed Sensing Obtained during the Gadoxetic Acid-enhanced Hepatobiliary Phase: Image Quality and Lesion Visibility Compared with a Standard T1-weighted Sequence.

PURPOSE: To evaluate the feasibility of breath-hold (BH) high-resolution (HR) T1-weighted gradient echo hepatobiliary phase (HBP) imaging using compressed sensing (CS) in gadoxetic acid-enhanced liver MRI in comparison with standard HBP imaging using parallel imaging (PI). METHODS: The study included 122 patients with liver tumors with hypointensity in the HBP who underwent both HR HBP imaging with CS and standard HBP imaging with PI. Two radiologists evaluated the liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, image noise, and overall image quality, as well as the lesion conspicuity on HR and standard HBP imaging and the contrast-enhanced (CE) MR cholangiography (MRC) image quality reconstructed from HBP images. As a quantitative analysis, the SNR of the liver and the liver to lesion signal intensity ratio (LLSIR) were also determined. RESULTS: The liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, and overall image quality as well as the lesion conspicuity and the LLSIR on HR HBP imaging with CS were significantly higher than those on standard HBP imaging (all of P < 0.001). The image quality of CE-MRC reconstructed from HR HBP imaging with CS was also significantly higher than that from standard HBP imaging (P < 0.001). Conversely, the SNR of liver in standard HBP was significantly higher than that in HR HBP with CS (P < 0.001). CONCLUSION: BH HR HBP imaging with CS provided an improved overall image quality, lesion conspicuity, and CE-MRC visualization when compared with standard HBP imaging without extending the acquisition time.

Three-Dimensional (3D) Breath-Hold Zoomed MR Cholangiopancreatography (MRCP): Evaluation of Additive Value to Conventional 3D Navigator Triggering MRCP in Patients With Branch Duct Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: To resolve drawbacks of navigator triggering (NT) three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP), several approaches were proposed to obtain 3D MRCP within a single breath-hold (BH). However, reduced field-of-view technique in the phase-encoding direction combined with two-dimensional spatially selective radiofrequency excitation pulses has not yet been applied to 3D BH MRCP. PURPOSE: To investigate the feasibility and the complementary value of 3D BH zoomed MRCP to conventional 3D NT MRCP in patients with branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) of the pancreas. STUDY TYPE: Retrospective. POPULATION: A total of 221 patients (116 male and 105 female, median age 73 years) with BD-IPMNs. FIELD STRENGTH/SEQUENCE: 3.0 T/3D turbo spin echo ASSESSMENT: MR images were analyzed by three radiologists (R.M., H.O., M.T., with 1, 13, and 17 years of experience) to compare blurring and motion artifacts, background suppression, visualization of main pancreatic duct (MPD), conspicuity of BD-IPMN, and overall image quality. STATISTICAL TESTS: Wilcoxon-signed rank, Mann-Whitney U, chi-squared or Fisher's exact tests (P < 0.05). RESULTS: Image quality was significantly higher on 3D NT MRCP images than on 3D BH zoomed MRCP (median (interquartile range); background suppression, 4 (4-4) vs. 3 (3-4); visualization of MPD, 4 (3-4) vs. 4 (3-4), conspicuity of BD-IPMN, 4 (3-4) vs. 3 (3-4); and overall image quality, 3 (3-4) vs. 3 (3-3)). However, in 32 (14%) patients, 3D NT MRCP showed a score of 1 or 2 in overall image quality. Regarding the conspicuity of BD-IPMN, a conspicuity score of 1 or 2 was rendered in 31 (14%) patients in 3D NT MRCP group. Conversely, 3D BH zoomed MRCP showed a score of 3 or 4 in 29 (94%) of these 31 patients. DATA CONCLUSION: 3D BH zoomed MRCP plays a complementary role to 3D NT MRCP, and may improve the conspicuity of BD-IPMNs in patients with irregular breathing pattern. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Assessment of the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase and hepatic signal changes in free-breathing continuous multiphasic dynamic EOB-MRI.

PURPOSE: To investigate the relationship between the hepatic contrast enhancement effect in the hepatobiliary phase (HBP) and the contrast enhancement parameters based on the data of continuous signal changes in free-breathing multiphasic dynamic EOB-MR imaging using a compressed sensing (CS) and the self-gating technique, and to clarify which contrast enhancement parameters are useful for estimating the hepatic enhancement effect in the HPB. METHOD: This study included 96 patients. The contrast enhancement ratio (CER) of the liver parenchyma from phase x to phase y was calculated as follows: CERy-x: (SIy -SIx)/SIx. The gradient of the regression line (GRL) was also calculated. Patients can be divided into two groups with sufficient or insufficient liver enhancement in the HBP, then each parameter was compared between these two groups. RESULTS: In the analysis of the arterioportal phases, CER7-pre in the sufficient HBP enhancement group was significantly higher than that in the insufficient HBP enhancement group (0.50 vs 0.44, p < 0.001). Regarding 5 min early hepatocyte phase (phases 1-28) analysis, significant differences were observed in CER28-pre, CER28-7 and Gradient28-7 between the two groups (0.64 vs 0.47, 0.10 vs 0.03, 1.27 vs 0.27, all p < 0.001). For the strength of correlation, CER7-pre, CER28-pre, CER28-7, and GRL28-7 had higher correlation coefficients, compared with the blood sampling data. CONCLUSION: CER in the arterio-portal phase and 5 min early hepatocyte phase had significant correlation with hepatic contrast enhancement effects in the 20 min HBP, suggesting that sufficient 20 min HBP enhancement may be estimated by the CER in the portal phase and 5 min early hepatocyte phase.

The kinetic analysis of breast cancer: An investigation of the optimal temporal resolution for dynamic contrast-enhanced MR imaging.

INTRODUCTION: There is wide agreement that morphologic features and enhancement kinetics should be evaluated for MRI of the breast, although there has been no clear consensus concerning optimal temporal resolutions. The objective of this study was to investigate the optimal temporal resolution for the kinetic analysis of breast cancers. METHODS: Thirty-four patients with 34 enhancing lesions of breast cancer who underwent dynamic contrast-enhanced MRI (DCE-MRI) on a 3.0-T scanner were included in this retrospective study. DCE-MRI was performed with an original temporal resolution of 10-s, and the values of pharmacokinetic parameters (Ktrans, Ve, Kep, and area under the curve (AUC)) were compared with selected data of 30-s and 60-s time intervals. RESULTS: Among the 34 lesions, 10 showed a wash out pattern, 16 showed a plateau pattern, and 8 showed a persistent enhancement pattern. The Ktrans value in the wash-out pattern was significantly higher than that of other time-intensity curve patterns (p < 0.01). The Kep and AUC also showed significant differences between the wash-out pattern and other types (p < 0.01). On comparing the perfusion parameters among different temporal resolutions, simulations showed that only the AUC differed significantly between the data acquired at a 10-s temporal resolution and that acquired at a 60-s time interval (p < 0.01). Although the comparison of the AUC between the 30-s and 60-s data also showed significant differences (p = 0.01), there was no significant difference between the 10-s and 30-s data (p = 0.17). CONCLUSIONS: DCE-MRI with a temporal resolution of 30-s preserves the kinetic information. Further prospective studies will be needed to investigate the trade-off between temporal and spatial resolution in DCE-MRI.

Influence of fat deposition on T1 mapping of the pancreas: evaluation by dual-flip-angle MR imaging with and without fat suppression.

PURPOSE: To evaluate the influence of fat deposition on T1 relaxation time of pancreatic parenchyma using dual-flip-angle T1 mapping with and without fat suppression. METHODS: Forty-five patients who underwent abdominal MR imaging including T1 mapping with dual-flip-angle method on 3T MRI were included. We measured T1 relaxation time of pancreatic parenchyma on the T1 map images with and without fat suppression. T1 relaxation time of bone marrow was also measured as a reference organ with abundant fat deposition. Fat signal fraction (FSF) was also measured at the same location as T1 map images. Then, the correlation between T1 relaxation time and FSF was assessed. RESULTS: T1 relaxation times of pancreatic parenchyma and bone marrow on the T1 map images without fat suppression showed significantly negative correlation with FSF (pancreas, r = - 0.394, P = 0.007; bone marrow, r = - 0.550, P < 0.001), while there were no significant correlations between them on the T1 map images with fat suppression. On the T1 map images without fat suppression, T1 relaxation times of pancreatic parenchyma as well as bone marrow in patients with FSF ≥ 10% were significantly shorter than those in patients with FSF < 10% (pancreas, P = 0.041; bone marrow, P = 0.005). Conversely, on the T1 map images with fat suppression, no significant differences in T1 relaxation times were found between two groups. CONCLUSION: T1 relaxation time of the pancreas on T1 mapping was influenced by the presence of fat deposition. Therefore, fat suppression technique in T1 mapping will be essential for evaluating T1 relaxation time of pancreatic parenchyma.

Incidentally detected pancreatic adenocarcinomas on computed tomography obtained during the follow-up for other diseases.

PURPOSE: To determine imaging findings of pancreatic adenocarcinomas incidentally detected on contrast-enhanced multiphasic dynamic computed tomography (CT) obtained during the follow-up for other diseases. METHODS: From January 2007 to December 2018, 14 patients with pancreatic adenocarcinomas incidentally detected on CT obtained during the follow-up for other diseases (incidental group) and 105 patients with pancreatic adenocarcinomas symptomatically detected on ultrasound or CT (non-incidental group) were included. Imaging characteristics of the tumor were compared between the two groups. Additionally, imaging findings prior to the detection of a tumor on previous CT images in the incidental group were also assessed. RESULTS: In cancers of the pancreas body/tail, there was a significantly smaller tumor size (median, 17 mm vs. 42 mm, p < 0.001), a significantly lower incidence of loss of fatty marbling (p = 0.025), vascular involvement (p < 0.001), lymph node metastasis (p = 0.046) and distant metastasis (p = 0.017), and a significantly higher incidence of preserved lobulation (p < 0.001) in the incidental group than in the non-incidental group. Regarding the cancers of the pancreas head, there were no significant differences in the radiological findings between the two groups. On previous CT images, small pancreatic nodules, secondary signs, and loss of fatty marbling tended to be the preceding findings of incidental pancreatic adenocarcinomas. CONCLUSION: Incidentally detected pancreatic adenocarcinomas in the pancreas body/tail were characterized by an earlier tumor stage than in cases of symptomatically detected pancreatic adenocarcinoma. Several CT findings prior to the detection of a tumor may be useful for the early detection of pancreatic adenocarcinoma during the follow-up for other diseases.

Liver imaging reporting and data system (LI-RADS) v2018: comparison between computed tomography and gadoxetic acid-enhanced magnetic resonance imaging.

PURPOSE: To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI. MATERIALS AND METHODS: Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images. RESULTS: Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P < 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P < 0.001) CONCLUSION: The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

Bilateral parotid oncocytoma with spontaneous intratumoral hemorrhage: a rare hypervascular parotid tumor with ASL perfusion.

We present a rare case of bilateral parotid oncocytoma with spontaneous intratumoral hemorrhage. Magnetic resonance imaging revealed multiple, bilateral, well-defined masses within the parotid glands with increased vascularity based on arterial spin labeling Magnetic Resonance (MR) perfusion imaging and restricted diffusion on diffusion-weighted imaging. During the clinical follow-up, the patient developed extensive hemorrhage from the largest tumor, presumably due to a combination of the hypervascular nature of oncocytoma and hemodialysis.

MRI of giant cell tumour of larynx: marked T 2 hypointensity due to abundant haemosiderin deposition.

Giant cell tumours (GCTs) are benign tumours commonly found in the long bones. Rarely, they may occur in the larynx, often resulting in hoarseness and anterior neck swelling. Since Wessely reported the first case of laryngeal GCT in 1940, 35 cases have been identified. Herein, we present a case of a 53-year-old male with GCT of the larynx that showed T 1 and T 2 hypointense signal on MRI, presumably owing to abundant haemosiderin deposition. We also discuss the imaging findings of CT and 18F-fludeoxyglucose positron emission tomography scans, as well as the pathological correlation.

Multi-modality imaging findings of methotrexate-related Epstein-Barr virus-associated hepatic tumor.

Methotrexate (MTX)-associated lymphoproliferative disorders (MTX-LPDs) that occur in rheumatoid arthritis patients who were administered MTX for long periods are well known. However, studies on their pathology in forming hepatic tumors are rare. An approach using diagnostic imaging modalities, mainly computed tomography (CT), is considered a very useful tool for the differential diagnosis of various hepatic tumors. In the present study, detailed findings of dynamic CT, magnetic resonance (MR) imaging, and contrast-enhanced ultrasonography of a hepatic tumor that was confirmed as infected by Epstein-Barr virus, in a rheumatoid arthritis patient administered MTX are presented.

Radiological image-guided placement of covered Niti-S stent for palliation of dysphagia in patients with cervical esophageal cancer.

The aim of this study was to evaluate the clinical effectiveness of covered Niti-S stent placement under multidetector CT and fluoroscopy guidance for the palliation of dysphagia in patients with cervical esophageal cancer. Under radiological imaging guidance using axial and sagittal CT scans, and fluoroscopy, Niti-S esophageal stents were placed in ten consecutive patients with complete obstruction caused by cervical esophageal cancer (9 men and 1 woman; age range = 54-79 years; mean age = 68.1 years) between February 2010 and December 2011. The procedure time and technical success rate were evaluated. Swallowing improvement was assessed by the following items: ability to eat and/or swallow (graded as follows: 3 = ability to eat normal diet, 2 = ability to eat semisolids, 1 = ability to swallow liquids, 0 = complete obstruction). Procedural and post-procedural complications were also evaluated. Survival (mean ± SD) was examined. The mean (±SD) procedure time was 40 ± 19 min (range = 21-69 min). Stent placement was technically successful in all patients; inadequate stent deployment did not occur in any case. Ability to eat and/or swallow was improved and scored 2.4 (score 3 in 5 cases, score 2 in 4 cases, score 1 in 1 case, and score 0 in no case) after stent placement. No major or post-procedural complications were encountered. The mean survival time was 131 ± 77 days (range = 31-259 days). Niti-S stents appeared to be a safe and effective device for the palliation of dysphagia caused by advanced cervical esophageal cancer. Multidetector CT and fluoroscopy image guidance helped the operators accurately place the stents in the cervical esophagus.

Percutaneous gastrostomy tube placement using a balloon catheter in patients with head and neck cancer.

BACKGROUND: Patients with head and neck cancer frequently require gastrostomy feeding. The aim of this study was to evaluate the safety and feasibility of percutaneous radiologic gastrostomy with push-type gastrostomy tubes using a rupture-free balloon (RFB) catheter under computed tomography (CT) and fluoroscopic guidance in patients with head and neck cancer with swallowing disturbance or trismus. METHODS: Percutaneous CT and fluoroscopic gastrostomy placement of push-type gastrostomy tubes using a RFB catheter was performed in consecutive patients with head and neck cancer between April 2007 and July 2010. The technical success, procedure duration, and major or minor complications were evaluated. RESULTS: Twenty-one patients (14 men, 7 women; age range, 55-78 years; mean age, 69.3 years) underwent gastrostomy tube placement. The tumor location was the pharynx (n = 8), oral cavity (n = 7), and gingiva (n = 6). Gastrostomy was performed in 15 patients during treatment and 6 patients after treatment. Percutaneous radiologic gastrostomy was technically successful in all patients. The median procedure time was 35 ± 19 (interquartile range) minutes (range, 25-75). The average follow-up time interval was 221 days (range, 10-920 days). No major complications related to the procedure were encountered. No tubes failed because of blockage, and neither tube dislodgement nor intraperitoneal leakage occurred during the follow-up periods. CONCLUSION: Percutaneous CT and fluoroscopic-guided gastrostomy with push-type tubes using a RFB catheter is a relatively safe and effective means of gastric feeding, with high success and low complication rates in patients with head and neck cancer in whom endoscopy was not feasible.

Superselective intra-arterial chemotherapy for advanced maxillary sinus cancer: an evaluation of arterial perfusion with computed tomographic arteriography and of tumor response.

OBJECTIVE: The purpose of our study was to elucidate the relationship between arterial perfusion in advanced maxillary sinus cancer which was opacified by superselective intra-arterial computed tomographic arteriography (IA-CTA) and the tumor response to intra-arterial chemotherapy. METHODS: Superselective IA-CTA was performed to identify the feeding arteries and their perfusion in advanced maxillary sinus cancer in 10 patients. Cisplatin was selectively infused into these feeding arteries, except for the internal carotid artery. RESULTS: The results were assessed in 9 of the 10 patients, and a complete response was achieved in 5 patients in whom either the entire tumor, or most of the tumor, was perfused by the branches of the external carotid artery. In 4 patients with a partial response, the residual tumors were seen in the territory of the perfusion defect or in the perfusion territory of the internal carotid artery. CONCLUSION: Superselective IA-CTA is a useful technique to correctly identify the intratumoral perfusion and to predict tumor response to the intra-arterial chemotherapy of advanced maxillary sinus cancer.