MR Imaging in Eclampsia

Background : The aim of this study is to determine the distribution and nature of Cranial MRI findings in eclamptic patients, and to correlate them with clinical and laboratory data. Materials and Methods : This study was conducted in the Department of Obstetrics and Gynecology in Sri Ramachandra Institute of Higher Education and Research. A total number of 35 Eclamptic patients were included in this study and they were analyzed retrospectively. Laboratory parameters, Blood Pressure and Cranial MRI was performed for all and the same were analyzed statistically. Results : Out of 35 Eclamptic patients, MR Imaging was normal in 6 patients. Among the 29 patients with abnormal MRI, Cortical-subcortical Lesion, appeared iso/hypo-intense in T-1 weighted images and hyper intense in T-2 weighted images. In most of the patients, occipital lobe was involved followed by involvement of other lobes such as Parietal, Frontal, Temporal, Basal Ganglia and Cerebellum. When patients with and without positive MRI findings were compared regarding clinical features such as Headache, Blurred Vision, Nausea and Vomiting, Epigastric Pain, Loss of Consciousness, Reduced Urine Output there was no statistically significant difference between the two groups. Similarly, there was no statistical difference in mean arterial pressures between MRI positive and MRI negative patients (p=0.218) however, it was found that those with MR imaging positive features had a higher Blood Pressure than those with MRI negative findings. Among the laboratory parameters, in the patients with abnormal MRI findings Fibrinogen was found to be significantly low than those with normal MRI findings (p=0.0002).

Real-time SERS monitoring anticancer drug release along with SERS/MR imaging for pH-sensitive chemo-phototherapy

In situ and real-time monitoring of responsive drug release is critical for the assessment of pharmacodynamics in chemotherapy. In this study, a novel pH-responsive nanosystem is proposed for real-time monitoring of drug release and chemo-phototherapy by surface-enhanced Raman spectroscopy (SERS). The Fe3O4@Au@Ag nanoparticles (NPs) deposited graphene oxide (GO) nanocomposites with a high SERS activity and stability are synthesized and labeled with a Raman reporter 4-mercaptophenylboronic acid (4-MPBA) to form SERS probes (GO-Fe3O4@Au@Ag-MPBA). Furthermore, doxorubicin (DOX) is attached to SERS probes through a pH-responsive linker boronic ester (GO-Fe3O4@Au@Ag-MPBA-DOX), accompanying the 4-MPBA signal change in SERS. After the entry into tumor, the breakage of boronic ester in the acidic environment gives rise to the release of DOX and the recovery of 4-MPBA SERS signal. Thus, the DOX dynamic release can be monitored by the real-time changes of 4-MPBA SERS spectra. Additionally, the strong T2 magnetic resonance (MR) signal and NIR photothermal transduction efficiency of the nanocomposites make it available for MR imaging and photothermal therapy (PTT). Altogether, this GO-Fe3O4@Au@Ag-MPBA-DOX can simultaneously fulfill the synergistic combination of cancer cell targeting, pH-sensitive drug release, SERS-traceable detection and MR imaging, endowing it great potential for SERS/MR imaging-guided efficient chemo-phototherapy on cancer treatment.

Evaluation of non-contrast magnetic resonance imaging as an imaging surveillance tool for hepatocellular carcinoma in at-risk patients

INTRODUCTION@#This study aimed to evaluate the potential of non-contrast-enhanced magnetic resonance (MR) imaging as an imaging surveillance tool for detection of hepatocellular carcinoma (HCC) in at-risk patients and to compare the performance of non-contrast MR imaging with ultrasonography (US) as a screening modality for the same.@*METHODS@#In this retrospective study, patients diagnosed with HCC between 1 January 2010 and 31 December 2015 were selected from our institution's cancer registry. Patients who underwent MR imaging and had US performed within three months of the MR imaging were included. For each MR imaging, two non-contrast MR imaging sequences - T2-weighted fat-saturated (T2-W FS) sequence and diffusion-weighted imaging (DWI) - were reviewed for the presence of suspicious lesions. A non-contrast MR image was considered positive if the lesion was seen on both sequences. The performance of non-contrast MR imaging was compared to that of hepatobiliary US for the detection of HCC.@*RESULTS@#A total of 73 patients with 108 HCCs were evaluated. Sensitivity of non-contrast MR imaging for the detection of HCC using T2-W FS and DWI was 93.2%, which was significantly higher than that of US, which was 79.5% (p = 0.02). In a subgroup of 55 patients with imaging features of liver cirrhosis, the sensitivity of non-contrast MR imaging was 90.9%, which was also significantly higher than that of US, which was 74.5% (p = 0.02).@*CONCLUSION@#Our pilot study showed that non-contrast MR imaging, using a combination of T2-W FS and DWI, is a potential alternative to US as a screening tool for surveillance of patients at risk for HCC.

Texture analysis of diffusion-weighted magnetic resonance imaging to identify atypically enhanced small hepatocellular carcinoma and dysplastic nodules under the background of cirrhosis / 中华肝脏病杂志

Objective@#To investigate the value of texture analysis based on diffusion-weighted magnetic resonance imaging (DWI) in the differential diagnosis of atypically enhanced small hepatocellular carcinoma (sHCC) and dysplastic nodules (DNs) in liver cirrhosis.@*Methods@#Data of 59 cases with atypical enhancement and solitary cirrhotic nodule (≤2 cm) confirmed by dynamic contrast enhanced MRI and surgical pathology specimen were analyzed retrospectively. Among them, 37 cases were of atypically enhanced sHCC and 22 cases of DNS. The DWI signal characteristics of the lesions were analyzed to measure the average apparent diffusion coefficient (ADC) value of the lesions, and the ADC ratio of the lesion to the liver parenchyma. MaZda software was used to manually draw the region of interest to extract the texture parameters of DWI lesions. The three sets (combination of Fisher coefficient, classification of error probability combined with average correlation coefficient and interactive information) were used to select the thirty optimal texture parameters. Raw data analysis (RDA), principal component analysis (PCA), linear discriminant analysis (LDA) and non-linear discriminant analysis (NDA) were performed for texture classification. The difference of ADC value and ADC ratio between sHCC and DNS group was compared by independent sample t-test, and χ2 test was used to compare the count data (or rate). ROC curve analysis was used to evaluate the diagnostic efficiency.@*Results@#The sensitivity, specificity and accuracy of DWI high-signal in the identification of atypically enhanced sHCC and DNs were 94.6% (35/37), 68.2% (15/22), and 84.7% (50/59), respectively. The ADC ratio of atypically enhanced sHCC was significantly lower than DNs, and the difference was statistically significant (t = 2.99, P = 0.002). The sensitivity, specificity, and accuracy for the diagnosis of atypically enhanced sHCC were 73.0% (27/37), 72.7% (16/22) and 72.9% (43/59), respectively. The sensitivity, specificity and accuracy of DWI texture analysis in diagnosing atypically enhanced sHCC were 94.6% (35/37), 95.5% (21/22) and 94.9% (56/59).The diagnostic efficiency of DWI texture analysis (AUC = 0.94) was significantly higher than DWI high-signal (AUC = 0.81) and ADC ratio (AUC = 0.72).@*Conclusion@#The texture analysis based on DWI can identify atypically enhanced sHCC and dysplastic nodules under the background of cirrhosis, and its efficacy is better than qualitative and quantitative DWI.

Predictive value of dynamic contrast-enhanced MRI of original plaque on carotid artery in-stent restenosis / 上海交通大学学报（医学版）

Objective: To explore the value of dynamic contrast-enhanced MR imaging (DCE-MRI) of original plaque to predict carotid artery in-stent restenosis (ISR). Methods: Forty cases of the patients with carotid atherosclerosis who were to undergo the carotid artery stenting (CAS) were included in this study. All participants underwent vessel wall MR imaging (VW-MRI) and DCE-MRI within one week before CAS. Carotid digital subtraction angiography (DSA) were performed at the sixth month to reassess the stenosis of stent. The correlation between DCE-MRI and ISR was evaluated. Results: The level of Ktran in ISR group was significantly higher than that in non-ISR group (P=0.000), and so was the vP (P=0.037). Ktrans could independently predict ISR (OR=1.43, 95%CI 1.17-1.56, P=0.012), and the cut-off value of Ktrans was 0.09 min-1 (sensitivity=100%, specificity=87.5%). Conclusion: Intraplaque inflammation may lead to excessive intimal hyperplasia after ISR. Ktrans could be a risk predictor of ISR with high sensitivity and specificity. DCE-MRI could be an effective tool to predict ISR.

Magnetic Resonance Imaging of Knee Injuries and It’s Correlation with Arthroscopic Findings

The knee joint is one of the most vulnerable and frequently injured joints of the body. X-ray, arthrographic, scintigraphic, ultrasound examinations hold their place in diagnosing knee injuries, but they are loosing precedence to computerised tomography (CT), magnetic resonance imaging (MRI) and arthroscopy. Role of magnetic resonance imaging (MRI) in the diagnosis of knee lesions has now become more evident. To find out the efficacy of MRI in diagnosing various ligamentous and meniscal injuries in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Methods: In this prospective interventional comparative study patients of all age group of either sex attending the orthopaedic OPD of IPGMER & SSKM Hospital with clinical features suggestive of soft tissue around knee were included in the study during the period of Feb 2008 to Aug 2009. MR imaging with GE make of 1.5 tesla (super conductive in nature) was used. The patients was evaluated in sagital, coronal and axial imaging planes. Results: In the present study 100 cases of knee evaluated based on the clinical history and examination a provisional diagnosis was made. About 44% of the patients were subjected to MRI within 10 weeks after the onset of their sufferings. Most common structure being injured was medial meniscus in about 64% cases. In our study, arthroscopy had been taken as gold standard but arthroscopy is useful for intraarticular structures and its injuries only. So the correlation of intraarticular structures i.e. meniscus & cruciates can be done only. Out of 100 patients, 48 cases showed ACL tears, 22 patients showed PCL tear arthroscopically. Out of 48 ACL tears confirmed by arthroscopy the diagnosis 5543by MRI was 48. Conclusions: MR is highly specific and highly sensitive in detection of cruciate ligament injuries in patients with acute as well as chronic injury. MR is more sensitive in detection of multiple meniscal tear that may be overlooked on sonography or arthroscopy.

Magnetic Resonance Imaging in Focal Liver Lesions with Diffusion Weighted Imaging (DWI) and Pathological Correlation

Background: Magnetic resonance signal intensity of focal liver lesions is affected by numerous pathologic factors. Lesion histologic features, such as cellularity, vascularity, stromal component, and intratumoral necrosis or hemorrhage, strongly affect T1 and T2 relaxation times. Aim and objectives: To assess the lesion characterization potential of MRI by evaluating unenhanced and dynamic gadolinium enhanced sequences, Histopathological correlation of the lesions to explain the major MRI findings and Assessment of the lesions by diffusion weighted imaging and investigating the role of b value in differentiating malignant and benign lesions Materials and methods: The study was done on 42 patients where contrast was given in 38 members. Focal liver lesions were analyzed based on clinical findings, laboratory investigations and MR imaging. Sonographically detected focal lesions were included in the study. Tissue diagnosis (FNAC/ Biopsy), surgery were done in feasible cases. In other cases, where surgery/ tissue diagnosis is not possible, follow up was done (range 3 months - 12 months, average 7.2 months). Results: MRI features of forty two patients with focal liver lesions were studied and morphological features and signal intensities of the masses were described. Contrast study was done in 39 cases. Of the 42 cases, 24 lesions were benign and 18 lesions were malignant. The mean age group ranged from 18 to 74 years with majority between 40 to 60 years. 61% of the lesions were located in right lobe of the liver. Contrast enhancement was done in 39 cases. Contrast enhancement was able to better delineate the cases. Specific pattern of contrast enhancement was typical of certain lesions as Karuna V, R Vikash Babu. Magnetic Resonance Imaging in Focal Liver Lesions with Diffusion Weighted Imaging (DWI) and Pathological Correlation. IAIM, 2019; 6(11): 81-93. Page 82 homogenous early arterial phase enhancement for hepatocellular carcinoma and ring enhancement in arterial phase for metastases. Delayed enhancement was specific for cholangiocarcinoma. Hemangiomas showed peripheral puddling and delayed central enhancement. Diffusion weighted imaging can be used as an additional tool in differentiating benign and malignant focal liver lesions. ADC value using a cut-off of 1.43 X 10 – 3 sec/ mm2 was a useful adjunct for determining benign cystic lesions and hemangiomas from malignant lesions. Conclusion: MRI was able to predict diagnosis in 38 of the 42 tumors. It could suggest the nature of all lesions in benign cysts, hemangiomas, focal nodular hyperplasia and metastases. But it was not possible to achieve a specific diagnosis in two early abscesses, one multifocal hepatocellular carcinoma and one case of regenerative nodules. This accounted for a detection rate of 90%. Thus MR imaging is a powerful tool for the evaluation of focal liver lesions. Pre contrast T1 weighted gradient echo images, T2 weighted images, in phase and out phase imaging, EPI – DWI and gadolinium enhanced T1 weighted images provide accurate characterization of the lesions.

Review of magnetic resonance imaging features of complications after anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) is an important stabiliser of the knee and is commonly torn in sports injuries. Common indications for imaging after ACL reconstruction include persistent symptoms, limitation of motion and re-injury. Important postoperative complications include graft failure, impingement, arthrofibrosis and graft degeneration. This article aimed to familiarise the radiologist with magnetic resonance (MR) imaging appearances of properly positioned intact ACL grafts and to provide a comprehensive review of MR imaging features of complications following ACL reconstruction.

Collison Tumor of Adenocarcinoma and Diffuse Large B-Cell Lymphoma in the Rectum: a Case Report and Literature Review

Collision tumor is a synchronous neoplasm wherein two histologically distinct tumors co-exist within the same anastomosis site. Collision tumor can occur in any organ, but the incidence is markedly rare. Additionally, preoperative diagnosis can be challenging to the radiologist. Herein, we report an age 60 male with collision tumor of rectal adenocarcinoma and diffuse large B-cell lymphoma, presented as a semi-annular wall thickening and bulky exophytic mass on MR imaging.

Efficacy, Efficiency, and Safety of Magnetic Resonance-Guided High-Intensity Focused Ultrasound for Ablation of Uterine Fibroids: Comparison with Ultrasound-Guided Method

OBJECTIVE: The purpose of this study was to compare efficacy, sonication energy efficiency, treatment time and safety of magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) and those of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for ablation of uterine fibroids. MATERIALS AND METHODS: This study included 43 patients with 44 symptomatic uterine fibroids treated with MRgHIFU and 51 patients with 68 symptomatic uterine fibroids treated with USgHIFU. After therapy, contrast-enhanced MRI was conducted and complete ablation was defined as 100% non-perfused volume (NPV) of fibroids. Patients with completely ablated fibroids were selected for the comparison of the treatment data and sonication parameters between MRgHIFU and USgHIFU treated groups. RESULTS: Thirteen completely ablated fibroids in 10 patients (23.3%, 10/43) were achieved with MRgHIFU and 28 completely ablated fibroids in 22 patients (43.1%, 22/51) were achieved with USgHIFU. In completely ablated fibroids, the energy-efficiency factor (EEF) was 5.1 ± 3.0 J/mm3 and 4.7 ± 2.5 J/mm3 in the MRgHIFU and USgHIFU, respectively (p = 0.165). There was a negative linear correlation between EEF and the NPV of fibroids for MRgHIFU (p = 0.016) and USgHIFU (p = 0.001). The mean treatment time was 174.5 ± 42.2 minutes and 114.4 ± 39.2 minutes in the MRgHIFU and USgHIFU procedures, respectively (p = 0.021). There were no severe adverse events and major complications after treatment. CONCLUSION: MRgHIFU and USgHIFU are safe and effective with the equivalent energy efficiency for complete ablation of fibroids. USgHIFU has shorter treatment time than MRgHIFU.

Early Changes in Apparent Diffusion Coefficient for Salivary Glands during Radiotherapy for Nasopharyngeal Carcinoma Associated with Xerostomia

OBJECTIVE: To evaluate the early changes in the apparent diffusion coefficient (ADC) of the salivary glands during radiotherapy (RT) and their association with the degree of xerostomia at 6 months after RT in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: We enrolled 26 patients with NPC who underwent RT. Each patient underwent diffusion-weighted MRI of the salivary glands at rest and with gustatory stimulation within 1 week before RT and 2 weeks after the beginning of RT. The ADC at rest (ADCR) and increase and increase rate with stimulation (ADCI, ADCIR) of the submandibular and parotid glands were calculated. The differences in the variables' values between 2 weeks after the beginning of RT and baseline (ΔADCR, ΔADCI, and ΔADCIR) were compared to the degree of xerostomia at 6 months after RT. RESULTS: The ADCR of the submandibular and parotid glands were both significantly higher at 2 weeks after the beginning of RT than found at baseline (both p < 0.01). The ADCI and ADCIR for the parotid glands were both significantly lower at 2 weeks after the beginning of RT than found at baseline (both p < 0.01). ΔADCI and ΔADCIR of the parotid glands were associated with the degree of xerostomia at 6 months after RT (r = −0.61 and −0.72, both p < 0.01). CONCLUSION: The ADCs of the salivary glands change early during RT. The differences in the ADC increase and increase rate of the parotid glands between 2 weeks after the beginning of RT and baseline were associated with the degree of xerostomia at 6 months after RT.

Clinics in diagnostic imaging (193). Sporadic Creutzfeldt-Jakob disease (sCJD)

A 68-year-old man presented with a three-week history of rapidly progressive dementia, gait ataxia and myoclonus. Subsequent electroencephalography showed periodic sharp wave complexes, and cerebrospinal fluid assay revealed the presence of a 14-3-3 protein. A probable diagnosis of sporadic Creutzfeldt-Jakob disease was made, which was further supported by magnetic resonance (MR) imaging of the brain showing asymmetric signal abnormality in the cerebral cortices and basal ganglia. The aetiology, clinical features, diagnostic criteria, various MR imaging patterns and radiologic differential diagnosis of sporadic Creutzfeldt-Jakob disease are discussed in this article.

Diffusion-Weighted MR Imaging of Unicystic Odontogenic Tumors for Differentiation of Unicystic Ameloblastomas from Keratocystic Odontogenic Tumors

OBJECTIVE: Differentiating unicystic ameloblastomas from keratocystic odontogenic tumors (KCOT) is necessary for the planning of different treatment strategies; however, it is difficult based on conventional CT and MR sequences alone. The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADCs) in the differentiation of the two tumors. MATERIALS AND METHODS: We prospectively studied 40 patients with odontogenic cysts and tumors of the maxillomandibular region using conventional MR imaging and DWI. ADCs were measured using 2 b factors (500 and 1000). RESULTS: Unicystic ameloblastomas (n = 11) showed free diffusion on DWI and a mean ADC value of 2.309 ± 0.17 × 10-3 mm2/s. KCOT (n = 15) showed restricted diffusion on DWI with a mean ADC value of 0.923 ± 0.20 × 10-3 mm2/s. The ADC values of unicystic ameloblastomas were significantly higher than those of KCOT (p < 0.001, Mann-Whitney U-test). An ADC cut-off value of 2.0 × 10-3 mm2/s to differentiate KCOT and unicystic ameloblastomas resulted in a 100% sensitivity and 100% specificity. Dentigerous cysts (n = 3) showed restricted diffusion on DWI and similar ADC values (1.257 ± 0.05 × 10-3 mm2/s) to those of KCOT. CONCLUSION: Diffusion-weighted imaging and ADC determination can be used as an adjuvant tool to differentiate between unicystic ameloblastomas and KCOT, although the ADC values of dentigerous cysts overlap with those of KCOT.

Detection of hypothalamic infarction in intraluminal middle cerebral artery occlusion model rat by DWI scanning / 上海交通大学学报（医学版）

Objective: To detect and evaluate the hypothalamic infarction in middle cerebral artery occlusion (MCAO) model rat. Methods: For 15 Sprague-Dawley rats weighed 200-250 g, aged 6-8 months, their right middle cerebral artery was occluded for 90 min by a silicon-coated 4-0 nylon filament and reperfused. Sprague-Dawley rats underwent diffusion weighted MR imaging (DWI) scanning (at 1 h and 24 h after reperfusion) and 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining (at 24 h after reperfusion) to determine the hypothalamic and cerebral infarct volume. The relationship between hypothalamic infarct volume and cerebral infarction volume was analyzed by DWI scanning. The results of TTC staining were compared with those of 24 h DWI scanning. Results: Fifteen Sprague-Dawley rats successfully received intraluminal MCAO/reperfusion procedures. The incidences of hypothalamic infarction on brain DWI scanning and TTC staining were 100% and 40% at 24 h after reperfusion, respectively. Therefore, DWI scanning was more sensitive than TTC staining to detect hypothalamic injury (P=0.001). The hypothalamic infarct volume on DWI scanning was (8.59±2.89) mm3 and (11.65±3.19) mm3 at 1 h and 24 h after reperfusion, respectively. On DWI scanning, hypothalamic and cerebral infarct volume at 24 h after reperfusion were correlated with each other significantly (r=0.573, P=0.025), so were the increases of hypothalamic and cerebral infarct volume (r=0.554, P=0.032) from 1 h to 24 h. Conclusion: DWI scanning was more sensitive than TTC staining to detect hypothalamic injury in intraluminal transient MCAO model. Hypothalamic and cerebral infarct volume were correlated with each other.

Multiparametric MRI in differentiation between sinonasal inverted papilloma and malignant transformation of inverted papilloma / 中华放射学杂志

Objective To identify the value of multiparametric MR imaging features including diffusion weighted (DW) and dynamic contrast-enhanced (DCE) MR imaging features in differentiation between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region.Methods Seventy-seven patients were included in this study,including 12 malignant transformation of inverted papilloma and 65 inverted papillomas.Conventional MRI including nonenhanced and static contrast-enhanced imaging,DCE-and the DW-MRI were analyzed.Differences in conventional MRI features,ADCs and DCE-MRI parameters between the two entities were determined by Fisher exact test,independent samples t-test and Mann-Whitney U test,respectively.Results There were significant differences in convoluted cerebriform pattern (P=0.045),necrosis (P=0.003) and orbit involvement (P＜ 0.01) between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region.The ADCs of inverted papilloma were significantly lower than those of malignant transformation of inverted papilloma (P＜0.01).There were significant differences in time to peak enhancement (P＜0.01),maximum contrast index (P=0.004) and time intensity curve types (P＜0.01) between the two entities.Conclusions A multiparametric approach using conventional MR imaging with added ADCs and DCE-MRI parameters had the potential to improve the differentiation between inverted papilloma and malignant transformation of inverted papilloma in the sinonasal region.

The value of magnetic resonance diffusion weighted imaging in early diagnosis for central gland prostate cancer / 中华内分泌外科杂志

Objective To investigate the value of magnetic resonance diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) in detection of central gland prostate cancer (CGPCa).Methods Routine MRI and DWI examination were performed in 25 CGPCa patients and 30 benign prostate heperplasia (BPH) patients.Then the ADC value was measured according to the image of the lesion after DWI,and the receiver op erating characteristic (ROC) curve was analyzed to select the best ADC value for diagnosis of CGPCa.Results The ADC value of CGPCa (0.89±0.12×10-3 mm2/s) was smaller than that of BHP (1.43±0.12x10-3 mm2/s),and the dif ference was statistically significant (P＜0.05).When the cut off point of ADC value was set at 1.192×10-3 mm2/s,the sensitivity was 80.0％ and the specificity was 85.0％.Conclusion DWI and ADC have clinical application value in diagnosis of CGPCa.

Differentiation between Glioblastoma and Primary Central Nervous System Lymphoma Using Dynamic Susceptibility Contrast-Enhanced Perfusion MR Imaging: Comparison Study of the Manual versus Semiautomatic Segmentation Method

BACKGROUND: Normalized cerebral blood volume (nCBV) can be measured using manual or semiautomatic segmentation method. However, the difference in diagnostic performance on brain tumor differentiation between differently measured nCBV has not been evaluated. PURPOSE: To compare the diagnostic performance of manually obtained nCBV to that of semiautomatically obtained nCBV on glioblastoma (GBM) and primary central nervous system lymphoma (PCNSL) differentiation. MATERIALS AND METHODS: Histopathologically confirmed forty GBM and eleven PCNSL patients underwent 3T MR imaging with dynamic susceptibility contrast-enhanced perfusion MR imaging before any treatment or biopsy. Based on the contrast-enhanced T1-weighted imaging, the mean nCBV (mCBV) was measured using the manual method (manual mCBV), random regions of interest (ROIs) placement by the observer, or the semiautomatic segmentation method (semiautomatic mCBV). The volume of enhancing portion of the tumor was also measured during semiautomatic segmentation process. T-test, ROC curve analysis, Fisher's exact test and multivariate regression analysis were performed to compare the value and evaluate the diagnostic performance of each parameter. RESULTS: GBM showed a higher enhancing volume (P = 0.0307), a higher manual mCBV (P = 0.018) and a higher semiautomatic mCBV (P = 0.0111) than that of the PCNSL. Semiautomatic mCBV had the highest value (0.815) for the area under the curve (AUC), however, the AUCs of the three parameters were not significantly different from each other. The semiautomatic mCBV was the best independent predictor for the GBM and PCNSL differential diagnosis according to the stepwise multiple regression analysis. CONCLUSION: We found that the semiautomatic mCBV could be a better predictor than the manual mCBV for the GBM and PCNSL differentiation. We believe that the semiautomatic segmentation method can contribute to the advancement of perfusion based brain tumor evaluation.

Anatomical Variants of Lister's Tubercle: A New Morphological Classification Based on Magnetic Resonance Imaging

OBJECTIVE: Lister's tubercle is used as a standard anatomical landmark in hand surgery and arthroscopy procedures. In this study, we aimed to evaluate and propose a classification for anatomical variants of Lister's tubercle. MATERIALS AND METHODS: Between September 2011 and July 2014, 360 MRI examinations for wrists performed using 1.5T scanners in a single institution were retrospectively evaluated. The prevalence of anatomical variants of Lister's tubercle based on the heights and morphology of its radial and ulnar peaks was assessed. These were classified into three distinct types: radial peak larger than ulnar peak (Type 1), similar radial and ulnar peaks (Type 2) and ulnar peak larger than radial peak (Type 3). Each type was further divided into 2 subtypes (A and B) based on the morphology of the peaks. RESULTS: The proportions of Type 1, Type 2, and Type 3 variants in the study population were 69.2, 21.4, and 9.5%, respectively. For the subtypes, the Type 1A variant was the most common (41.4%) and conformed to the classical appearance of Lister's tubercle; whereas, Type 3A and 3B variants were rare configurations (6.4% and 3.1%, respectively) wherein the extensor pollicis longus tendon coursed along the radial aspect of Lister's tubercle. CONCLUSION: Anatomical variations of Lister's tubercle have potential clinical implications for certain pathological conditions and pre-procedural planning. The proposed classification system facilitates a better understanding of these anatomical variations and easier identification of at-risk and rare variants.

The Effectiveness of Ferritin as a Contrast Agent for Cell Tracking MRI in Mouse Cancer Models

PURPOSE: We aimed to investigate the effectiveness of ferritin as a contrast agent and a potential reporter gene for tracking tumor cells or macrophages in mouse cancer models. MATERIALS AND METHODS: Adenoviral human ferritin heavy chain (Ad-hFTH) was administrated to orthotopic glioma models and subcutaneous colon cancer mouse models using U87MG and HCT116 cells, respectively. Brain MR images were acquired before and daily for up to 6 days after the intracranial injection of Ad-hFTH. In the HCT116 tumor model, MR examinations were performed before and at 6, 24, and 48 h after intratumoral injection of Ad-hFTH, as well as before and every two days after intravenous injection of ferritin-labeled macrophages. The contrast effect of ferritin in vitro was measured by MR imaging of cell pellets. MRI examinations using a 7T MR scanner comprised a T1-weighted (T1w) spin-echo sequence, T2-weighted (T2w) relaxation enhancement sequence, and T2*-weighted (T2*w) fast low angle shot sequence. RESULTS: Cell pellet imaging of Ad-hFTH in vitro showed a strong negatively enhanced contrast in T2w and T2*w images, presenting with darker signal intensity in high concentrations of Fe. T2w images of glioma and subcutaneous HCT116 tumor models showed a dark signal intensity around or within the Ad-hFTH tumor, which was distinct with time and apparent in T2*w images. After injection of ferritin-labeled macrophages, negative contrast enhancement was identified within the tumor. CONCLUSION: Ferritin could be a good candidate as an endogenous MR contrast agent and a potential reporter gene that is capable of maintaining cell labeling stability and cellular safety.

Evaluation of the Differences of Myocardial Fibers between Acute and Chronic Myocardial Infarction: Application of Diffusion Tensor Magnetic Resonance Imaging in a Rhesus Monkey Model

OBJECTIVE: To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. MATERIALS AND METHODS: Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). RESULTS: Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10(-4) mm2/s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10(-4) mm2/s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°-11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°-53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°-66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°-64.9 ± 4.3°). CONCLUSION: Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models.