Conventional MR Findings Research Articles

New Enhancement beyond Radiation Field Improves Survival Prediction in Patients with Post-Treatment High-Grade Glioma.

The imaging signs which can accurately predict survival prognosis after standard treatment of high-grade glioma (HGG) are highly desirable. This study aims to explore the role of new enhancement beyond radiation field (NERF) in the survival prediction in patients with post-treatment HGG. The present study included 142 pathologically confirmed HGG patients who had received standard treatment. NERF, as well as other conventional MR findings and clinical variables, were included in univariate and multivariate analyses for evaluating their impactions on progression-free survival (PFS) and overall survival (OS). Univariate analysis showed that histological grade (p=0.008) and NERF (p=0.001) were the prognostic variables for poor PFS, whereas histological grade (p=0.017), NERF (p=0.001), and new subventricular zone enhancement (nSVZE) (p=0.001) were prognostic variables for poor OS. The multivariate analysis showed that NERF (HR 3.93; 95% CI 1.93–8.01; p=0.001) and nSVZE (HR 3.92; 95% CI 1.95–7.89; p=0.001) were the prognostic variables for poor OS. However, only nSVZE was (HR 3.29; 95% CI 2.04–5.28; p=0.001) the prognostic variable for poor PFS. When combining the NERF with the clinical and other MR variables, the highest AUC (0.924) and specificity (0.899) for predicting poor OS were achieved. The location of new developed enhancements relevant to high dose radiation field appears to be the main determinant of their prognostic value. Our results suggest that the new enhancement beyond radiation field can improve the survival prediction in patients with HGG after standard treatment.

Evaluation of perinatal hypoxic encephalopathy with advanced MR sequences

Perinatal hypoxic ischemic encephalopathy (HIE) among important causes of neurological morbidity and mortality in full-term neonates. Identifying ischemic injury clinically usually is difficult in the immediate postnatal period, nonspecific clinical features are present and consid-erations regarding initiation of active life preserving therapies are needed. MR imaging is the most sensitive and specific imaging tech-nique available for the assessment of perinatal birth asphyxia related brain injury in term-born neonates. This study investigates the utility of MR spectroscopy peak ratios, ADC values along with conventional MRI. To compare the association of encephalopathy following hypoxia in term neonates with proton MRS ratios and ADC values. Conventional MRI (T1 and T2) along with DWI followed by MR Spectroscopy was done in 25 term neonates with clinical and neurological features of en-cephalopathy following perinatal asphyxia. MRS peak ratios, DWI with ADC values and conventional MRI findings were compared with each grade of HIE. Among 25 patients suspected cases of hypoxic enceph-alopathy, 15 patients had early positive conventional MR findings, 16 patients had late positive conventional MR findings, 19 patients had positive DWI, and 22 patients had positive MRS with high lac-tate/choline and lactate/NAA ratio. Higher association was found be-tween spectroscopy findings and hypoxic ischemic injury compared to MR imaging and ADC. The combination of MRS, DWI with ADC values and conventional MRI may assist in localizing and predicting the severi-ty of ischemic injury in HIE patients.

Conventional MR and diffusion-weighted imaging of musculoskeletal soft tissue malignancy: correlation with histologic grading.

To evaluate proven soft tissue musculoskeletal malignancies blinded to their Fédération Nationale des Centres de Lutte Contre le Cancer histologic grades to identify the predictive values of conventional MR findings and best fit region of interest (ROI) apparent diffusion coefficient (ADC) measurements. Fifty-one consecutive patients with different histologic grades were evaluated by four readers (R1-4) of different experience levels. Quantitatively, the maximum longitudinal size, tumor to muscle signal intensity ratios, and ADC measurements and, qualitatively, the spatial location of the tumor, its signal alterations, heterogeneity, intralesional hemorrhage or fat, and types of enhancement were assessed. Intraclass correlation, weighted kappa, ANOVA, and Fisher exact tests were used. There were 22/51 (43%) men (mean age ± SD = 52 ± 16years) and 29/51 (57%) women (mean age ± SD = 54± 17years), with the majority of tumors 38/51 (75%) in the lower extremities. Histologic grades were I in 8/51 (16%), II in 17/51 (33%), and III in 26/51 (51%), respectively. The longitudinal dimensions were different among three grades (p = 0.0015), largest with grade I. More central enhancements and deep locations were seen in grade III tumors (p = 0.0191, 0.0246). The ADC mean was significantly lower in grade III than in grade I or II (p < 0.0001 and p = 0.04). The ADC min was significantly lower in grade III than in grade I (p = 0.02). Good to excellent agreements were seen for T1/T2 tumor/muscle ratios, longitudinal dimension, and ADC (ICC = 0.60-0.98). Longitudinal tumor dimension, central enhancement, and ADC values differentiate histology grades in musculoskeletal soft tissue malignancy with good to excellent inter-reader reliability. • The longitudinal tumor dimension of grade III malignancy is smaller than that of grade I (p < 0.0001), and higher-grade tumors are located deeper (p = 0.0246). • The ADC mean is significantly lower in grade III than in grade I or grade II (p < 0.0001 and p = 0.04). • The ADC minimum is significantly lower in grade III than in grade I (p = 0.02).

Conventional, diffusion, and permeability MR findings in ocular medulloepithelioma.

To describe the neuroradiological features of intraocular medulloepithelioma. We retrospectively analyzed the clinical, histopathological, and MRI data of five children with medulloepithelioma. In addition to conventional images, DWI was performed in four patients and mean ADC was calculated; this was limited to the technique of this cohort of patients. DCE was performed in all patients. This is the first paper that presents diffusion and perfusion characteristics of medulloepithelioma. Four tumors were malignant teratoid variants, two non-teratoid variants. Tumors were hyperintense on T1-weighted images and hypointense on T2-weighted images. Calcifications were detectable in two out of five tumors. Cavities were detectable in three out of five tumors. All tumors showed some degree of enhancement. The mean ADC of all four patients was 1.156 ± 242.75 × 10-3mm2/s. Mean ktrans, Ve, Kep, TME, AUC, SER, and peak enhancement were 0.082 ± 0.054, 0.19 ± 0.076, 0.31 ± 0.084, 0.97 ± 0.0784, 1.22 ± 0.81, 67.34 ± 31.7, and 14.84 ± 7.34 respectively. TICs showed a very high ratio of slow increase, > 50% persistence and some degree of wash out. Teratoid variants showed higher K-trans, AUC, VE, TME, and persistent TIC pattern than non-teratoid ones, while plateau pattern ratio was lower. Conventional MR findings were similar to previously reported cases. Mean ADCs were moderately high. TICs showed slow increase and presence of wash out. K-trans, AUC, VE, and TME were higher in teratoid variants. Permeability parameters in differential diagnosis with lesions mimicking medulloepithelioma need further investigations.

CT and MR imaging of non-cavernous cranial dural arteriovenous fistulas: Findings associated with cortical venous reflux

PurposeTo compare the conventional CT and MR findings of DAVFs in relation to the venous drainage pattern on digital subtraction angiography (DSA). Materials and MethodsCross-sectional imaging findings (CT and/or MR) in 92 patients were compared to the presence of cortical venous reflux (CVR) on DSA. ResultsImaging features significantly more prevalent in patients with CVR included: abnormally dilated and tortuous leptomeningeal vessels (92% vs. 4%, p<0.001) or medullary vessels (69% vs. 0%, p<0.001), venous ectasias (45% vs. 0%, p<0.001) and focal vasogenic edema (38% vs. 0%, p<0.001). The following findings trended towards association but did not reach the p value established following Bonferroni correction: dilated external carotid artery branches (71% vs. 38%, p=0.005), cluster of vessels surrounding dural venous sinus (50% vs. 19%, p=0.009), presence of hemorrhage (33 vs. 12%, p=0.040), and parenchymal enhancement (21% vs. 0%, p=0.030). ConclusionIn the appropriate clinical setting, recognition of ancillary signs presumably related to venous arterialization and congestion as well as arterial feeder hypertrophy should prompt DSA confirmation to identify DAVFs associated with CVR.

Evaluation of apparent diffusion coefficient associated with pathological grade of lung carcinoma, before therapy.

To investigate the feasibility and utility of apparent diffusion coefficient (ADC) in predicting the tumor cellular density and grades of lung cancers. Forty-one consecutive patients (26 men and 15 women; mean age, 59.9 years) with histologically proven lung cancers were enrolled in the study and underwent MR examination. ADC values and tumor cellular density of different histological grades were analyzed. The relationship of the ADC with tumor cellular density and grades were also evaluated. The ADC values of lung cancer in grade III was significantly lower than those in grade I and grade II (P = 0.008 and 0.011, respectively). The cellular density in grade III was significantly higher than other two grades (P = 0.029 and 0.022, respectively). ADC value of lung cancer correlated negatively with grades and tumor cellular density (P = 0.001 and P = 0.001, respectively). According to the ROC analysis, the cutoff value of ADC was 1.175 × 10(-3) mm(2) /s with the optimal sensitivity (88.2%) and specificity (62.5%), respectively. ADC measurement of lung cancer was a helpful method to evaluate the pathological grade and tumor cellular density. The quantitative analysis of ADC in conjunction with conventional MR findings could provide more valuable information for the assessment of pulmonary tumor. J

Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee.

This study assesses the accuracy of 3-Tesla (3-T) conventional MR imaging, 3-T MR arthrography, and the combined use of conventional MR and MR arthrography in the diagnosis of meniscal retears as compared with arthroscopy. The study also assess whether there are false-negative cases in which injected contrast does not extend into the meniscus despite a meniscal retear being seen on arthroscopy. One hundred consecutive knee MR arthrograms performed on patients with previous knee surgery were reviewed retrospectively. 3-T conventional MR imaging, 3-T MR arthrography, and the combined use of conventional MR and MR arthrography were assessed for meniscal retears as compared with arthroscopy. The criterion used to diagnose a meniscal retear on MR arthrogram was injected contrast tracking into the meniscus. All patients underwent second-look arthroscopy. Seventy-four patients had conventional MR findings consistent with a meniscal retear. In 83 of the 100 patients, intraarticular contrast helped in demonstrating a retear. In ten patients, there were MR findings consistent with a meniscal retear despite intra-articular contrast not tracking into the meniscus. Ninety-four of the 100 patients had meniscal retears on second-look arthroscopy. Three-Tesla conventional MR examination was 78% sensitive and 75% specific, MR arthrogram examination was 88% sensitive and 100% specific, and the combined use of MR and MR arthrogram imaging was 98% sensitive and 75% specific in the diagnosis of a meniscal retear. The combined use of 3-T MR and MR arthrography allows for high sensitivity and specificity in meniscal retear detection. In some patients, intraarticular contrast will not track into a meniscal retear. When MR findings are consistent with a meniscal retear but contrast does not extend into the meniscus, a meniscal retear is likely.

MR imaging of intracranial hemangiopericytomas

To describe the MR features of primary intracranial hemangiopericytomas (HPCs) on conventional imaging, diffusion and MR spectroscopy and aim to determinate distinguishing features from meningiomas. From 2006 to 2012, seven patients with pathologically confirmed primary intracranial HPCs were included. The clinical data, conventional MR findings (n=7), DWI features (n=7) and MR spectroscopy (n=5) were retrospectively analyzed. ADC values of the HPCs (n=7) were measured on ADC map and were compared with that of contralateral normal white matter. Of the seven HPCs, four were anaplastic HPCs (WHO grade III) and three were HPCs (WHO grade II). MR pattern consisted in lobulated or irregular margin tumors in all cases with cross-leaf growth on both side of the falx in two cases. The lesions showed mainly iso signal (n=4) on T1 WI and heterogeneous high signal (n=5) on T2 WI. Heterogenity was mainly related to intra tumoral hemorrhage (n=4), and proeminent intratumoral flow voids (n=3). Marked heterogeneous enhancement (n=5) with dural tail (n=4) was noted. All tumours showed significant peritumoral edema. ADC values of the tumor tissue component range between 0.638 and 1.50×10(-3)mm/s(2) (average=1,02). Three grade II HPCs showed higher values compared to normal parenchyma ADC (range between 0.772 and 0.930×10(-3)mm/s(2) with average of 0.830), whereas grade III HPCs showed either equal (three cases) or decreased ADC values (one case). MRS showed in all cases markedly increased Cho with lip/lac peak, decreased Cr and almost absent NAA. High mI peak with large glutamine/glutamate were noted in the three grade II HPCs. Conventional MR pattern when combined with DWI and MRS findings are highly suggestive of HPC and appear valuable data to differentiate HPCs from meningiomas.

Use of conventional MR imaging and diffusion‐weighted imaging for evaluating the risk grade of gastrointestinal stromal tumors

To study the risk grade of gastrointestinal stromal tumors (GISTs) with conventional MR imaging and diffusion-weighted imaging (DWI). The abdominal MR images with DWI of 23 patients with pathologically proven GISTs during January 2010 to May 2011 were retrospectively reviewed. The conventional MR imaging findings and apparent diffusion coefficient (ADC) values of the tumors related to the risk grade were analyzed. In the 23 patients, there were 13 patients with high-risk, 5 with medium-risk, 5 with low-risk, and 0 with very low-risk GISTs. Most of the conventional MR findings of the tumors did not correlate with the risk grade. The only exception to this was the correlation between risk grade and the enhancement degree of the tumor after Gd-DTPA. The ADC values were, respectively, (1.04 ± 0.13) × 10(-3) mm(2) ·s(-1) , (1.59 ± 0.06) × 10(-3) mm(2) ·s(-1) and (1.94 ± 0.08) × 10(-3) mm(2) ·s(-1) (P < 0.05) in the high-, medium-, and low-risk grade groups. The ADC values of GISTs decreased with the increase of the risk grade of the tumors (r = -0.957; P < 0.05). DWI can be used to assess the risk grade of GISTs, but conventional MR imaging is of limited use.

MRI with Magnetic Resonance Spectroscopy of multiple brain abscesses secondary to Scedosporium apiospermum in two immunocompromised patients

Scedosporium apiospermum is a deadly fungal infection that can infect the central nervous system, particularly in immunocompromised patients. We present two cases of Scedosporium brain abscesses. The first case was fatal and relevant conventional MRI and MR spectroscopy findings are discussed. To our knowledge, this is the first reported case of MR spectroscopy in Scedosporium apiospermum abscesses. In the second case, the patient recovered and conventional MR findings are followed over several months. In the appropriate clinical setting, conventional MR imaging and MR spectroscopy may facilitate diagnosis, earlier initiation of antifungal pharmacotherapy and surgical intervention in this frequently fatal infection.

Morphometry and diffusion MR imaging years after childhood traumatic brain injury

Objective Our goal was to detect possible unrecognized injury in cerebral white matter (WM) in adult survivors of traumatic brain injury (TBI) during childhood, who showed no detectable axonal injury or chronic contusion on late conventional MRI. Material and methods We used voxel-based morphometry (VBM) to detect subtle structural changes in brain morphology and diffusion-tensor imaging (DTI) to non-invasively probe WM integrity. By means of VBM and DTI we examined a group of 12 adult patients who suffered from childhood closed head injury without axonal injury on late conventional MRI. Results Patients sustained complicated mild or moderate-to-severe TBI with a mean of 7 points based on the Glasgow Coma Scale. The mean time after trauma was 19 years (range 7–31 years). For VBM, group comparisons of segmented T1-weighted grey matter and WM images were performed, while for DTI we compared the fractional anisotropy and mean diffusivity (MD) between the groups. Patients presented with higher MD in the right cerebral white matter, bilaterally in the forceps major and in the body and splenium of the corpus callosum. These findings were supported by VBM, which showed reduced WM volume bilaterally, mainly along the callosal splenium. Conclusion Our results indicate that persistent focal long-term volume reduction and underlying WM structural changes may occur after TBI during childhood and that their effects extend into adulthood. Normal late conventional MR findings after childhood TBI do not rule out non-apparent axonal injury.

Active Crohn's Disease in the small bowel: Evaluation by diffusion weighted imaging and quantitative dynamic contrast enhanced MR imaging

To determine relative diagnostic value of MR diffusion and perfusion parameters in detection of active small bowel inflammation in patients with Crohn's disease (CD). We reviewed 18 patients with active CD of terminal ileum (TI) who underwent MR enterography (MRE; including dynamic contrast enhanced MRI and diffusion-weighted MRI). Conventional MRI findings of TI were recorded. Regions of interest were drawn over TI and normal ileum to calculate apparent diffusion coefficient (ADC), the volume transfer constant (K(trans)) and the contrast media distribution volume (v(e)). Receiver operating characteristic analysis was used to determine their diagnostic performance. Among conventional MR findings, mural thickening and increased enhancement were present in all actively inflamed small bowel. K(trans), v(e), and ADC values differed significantly between actively inflamed TI and normal ileum (0.92 s(-1) versus 0.36 s(-1); 0.31 versus 0.15 ± 0.08; 0.00198 mm(2)/s versus 0.00311 mm(2)/s; P < 0.001). Area under the curve (AUC) for K(trans), v(e), and ADC values ranged from 0.88 to 0.92 for detection of active inflammation. Combining K(trans) and ADC data provided an AUC value of 0.95. Dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) provide quantitative measures of small bowel inflammation that can differentiate actively inflamed small bowel segments from normal small bowel in CD. DWI provides better sensitivity compared with DCE-MRI and combination of ADC and K(trans) parameters for analysis can potentially improve specificity.

Contralateral hemimicrencephaly in neonatal hemimegalencephaly

Identification of abnormalities in the contralateral hemisphere in patients with hemimegalencephaly is critical in their management. In this report, we present a 5-day-old neonate with hemimegalencephaly who demonstrated an enlarged ipsilateral cerebral hemisphere and diffuse volume loss in the contralateral hemisphere on conventional MR imaging sequences. The ipsilateral frontal white matter demonstrated relatively increased NAA, fractional anistropy, and cerebral blood volume values compared to published normative data. In addition, the white matter of the contralateral hemisphere demonstrated elevated lactate and increased mean diffusivity compared to published normative data, supporting the abnormal conventional MR findings. Advanced MR neuroimaging techniques may help further confirm and characterize abnormalities in the smaller contralateral hemisphere in neonatal hemimegalencephaly.

A Case of Isolated Focal Cerebellar Heterotopia in a Patient Affected by HHT: MR and MR Spectroscopy Findings

We describe the MR study of an isolated cerebellar heterotopia , incidentally found in a 17 year-old girl affected by hereditary hemorrhagic teleangectasia. Conventional MR, DWI and MR spectroscopy findings are described; at the best of our knowledge, spectroscopic findings have not been previously reported in this setting. A possible relation between a microvascular damage due to HHT and the cerebellar malformation is hypotised.

Foramen of Monro meningioma with atypical appearance: CT and conventional MR findings

Intraventricular meningiomas have often been reported; however, literature reveals very few cases localized within foramen of Monro. Herein we report a 57-year-old woman admitted with obstructive hydrocephalus-related symptoms. Strikingly, the lesion was completely calcified in CT and had no marked solid component on MRI. The lesion was completely removed by surgical resection with a transfrontal intraventricular approach. The resected mass was histopathologically diagnosed as meningioma. The patient's symptoms resolved immediately after the operation.

MR cholangiopancreatography in malignant biliary obstruction

Malignant lesions of the biliary tract are a frequent occurrence, typically presenting with clinical findings of obstructive jaundice. The authors discuss the role of MR cholangiopancreatography (MRCP) as a second level diagnostic technique, which can provide information regarding not only the location, but also the cause of the obstruction. This can be obtained if MRCP is considered as part of a complete study of the upper abdomen, with acquisition of T1- and T2-weighted images. The “all-in-one” approach may provide the identification, characterization, and staging of the lesion, giving the clinician all the information necessary for the planning of adequate treatment. Typical MR features of cholangiocarcinoma are provided, as well as conventional MR and MRCP findings in pancreatic carcinoma, periampullary carcinoma, and biliary obstruction secondary to hilar lymphadenopathy and metastatic lesions.