Contrast-enhanced T1-weighted Magnetic Resonance Imaging Research Articles

Diagnostic Performance and Safety of Positron Emission Tomography Using 18F-Fluciclovine in Patients with Clinically Suspected High- or Low-grade Gliomas: A Multicenter Phase IIb Trial.

Objective(s):The study objective was to assess the diagnostic performance of positron emission tomography (PET) for gliomas using the novel tracer 18F-fluciclovine (anti-[18F]FACBC) and to evaluate the safety of this tracer in patients with clinically suspected gliomas.Methods:Anti-[18F]FACBC was administered to 40 patients with clinically suspected high- or low-grade gliomas, followed by PET imaging. T1-weighted, contrast-enhanced T1-weighted, and fluid-attenuated inversion recovery (or T2-weighted) magnetic resonance imaging (MRI) scans were obtained to plan for the tissue collection. Tissues were collected from either “areas visualized using anti-[18F]FACBC PET imaging but not using contrast-enhanced T1-weighted imaging” or “areas visualized using both anti-[18F]FACBC-PET imaging and contrast-enhanced T1-weighted imaging” and were histopathologically examined to assess the diagnostic accuracy of anti-[18F]FACBC-PET for gliomas.Results:The positive predictive value of anti-[18F]FACBC-PET imaging for glioma in areas visualized using anti-[18F]FACBC-PET imaging, but not visualized using contrast-enhanced T1-weighted images, was 100.0% (26/26), and the value in areas visualized using both contrast-enhanced T1-weighted imaging and anti-[18F]FACBC-PET imaging was 87.5% (7/8). Twelve adverse events occurred in 7 (17.5%) of the 40 patients who received anti-[18F]FACBC. Five events in five patients were considered to be adverse drug reactions; however, none of the events were serious, and all except one resolved spontaneously without treatment.Conclusion:This Phase IIb trial showed that anti-[18F]FACBC-PET imaging was effective for the detection of gliomas in areas not visualized using contrast-enhanced T1-weighted MRI and the tracer was well tolerated.

Hepatic hydatid cyst.

A 58-year-old man was admitted for the evaluation of an incidentally detected hepatic mass. Intravenous contrast-enhanced abdominal computed tomography scan in conjunction with contrast-enhanced T1-weighted magnetic resonance imaging (MRI) showed a smooth-margined cyst in the left lateral hepatic segment, which measured 8.5 cm in diameter at the widest point, and contained several other small cysts. There was also another sizable cyst in right hepatic lobe, measuring roughly 3.3 cm in diameter, with a small calcification along the wall (Fig. 1). T2-weighted MRI showed additional small low signal intensity tubular lesions within the large cyst (Fig. 2). Figure 1 Contrast-enhanced abdominal computed tomography scan shows a smooth-margined large cyst in left lateral hepatic segment (white arrow), containing several small daughter cysts (arrowheads) and another cyst in the right hepatic lobe, with a small calcification ... Figure 2 T2-weighted magnetic resonance imaging shows a high signal intensity large cyst containing multiple smaller bright signal intensity cysts, and a few small hypointensity tubular lesions (arrows). At the time, the patient's laboratory findings, including white blood cell count, differential eosinophil count, C-reactive protein, and liver function test, were within normal range. He often ate canine flesh and pork; however, his stool examination was negative for parasite egg. The patient underwent left lateral hepatic sectionectomy and right hepatic tumorectomy. The gross morphology of the large cyst in the left lateral hepatic segment showed fibrotic material, several small gelatinous fluid collections, serous fluid, and a few small dead tubular worms. They were identified pathologically as Echinococcus granulosus. The other cyst in right hepatic lobe was also considered as a hepatic hydatid cyst. Echinococcosis in humans is a zoonotic secondary infection by the larval stages of the cestode species of the genus Echinococcus. Cystic echinococcosis (CE) is caused by E. granulosus. The intermediate host, humans, enter the organism's life cycle through exposure to infected canine feces. If the cyst contains a living worm, peripheral eosinophilia can be frequently seen. The liver is the most common organ of CE. In the case of hepatic CE, the right hepatic lobe is more frequently involved, and the morphological form, about 75% of cases, is a unilocular simple cyst. However, a large mother cyst containing multiple small daughter cysts in the liver is considered relatively typical and highly specific imaging finding for the diagnosis of hepatic hydatid cyst. In this case, there were a few small tubular structures within the cyst on MRI were regarded as dead worms in the pathologic specimen. A second cyst with a small calcification is non-specific imaging finding. In the presented case, it was another hepatic hydatid cyst. According to the classification of a hepatic hydatid cyst, a cyst with calcification is considered a dead cyst.

Assessment of Arterial Wall Enhancement for Differentiation of Parent Artery Disease from Small Artery Disease: Comparison between Histogram Analysis and Visual Analysis on 3-Dimensional Contrast-Enhanced T1-Weighted Turbo Spin Echo MR Images at 3T

ObjectiveThe purpose of this study was to compare the histogram analysis and visual scores in 3T MRI assessment of middle cerebral arterial wall enhancement in patients with acute stroke, for the differentiation of parent artery disease (PAD) from small artery disease (SAD).Materials and MethodsAmong the 82 consecutive patients in a tertiary hospital for one year, 25 patients with acute infarcts in middle cerebral artery (MCA) territory were included in this study including 15 patients with PAD and 10 patients with SAD. Three-dimensional contrast-enhanced T1-weighted turbo spin echo MR images with black-blood preparation at 3T were analyzed both qualitatively and quantitatively. The degree of MCA stenosis, and visual and histogram assessments on MCA wall enhancement were evaluated. A statistical analysis was performed to compare diagnostic accuracy between qualitative and quantitative metrics.ResultsThe degree of stenosis, visual enhancement score, geometric mean (GM), and the 90th percentile (90P) value from the histogram analysis were significantly higher in PAD than in SAD (p = 0.006 for stenosis, < 0.001 for others). The receiver operating characteristic curve area of GM and 90P were 1 (95% confidence interval [CI], 0.86–1.00).ConclusionA histogram analysis of a relevant arterial wall enhancement allows differentiation between PAD and SAD in patients with acute stroke within the MCA territory.

Differences In High-Intensity Signal Volume Between Arterial Spin Labeling And Contrast-Enhanced T1-Weighted Imaging May Be Useful For Differentiating Glioblastoma From Brain Metastasis.

To determine whether differences in tumor volume between arterial spin labeling (ASL) and contrast-enhanced T1-weighted MR images (CE+T1WI) can help differentiate glioblastoma (GBM) from brain metastasis. Patients with a diagnosis of GBM (n=25) or brain metastasis (n=13) were examined by both conventional and ASL MR imaging. Volumes of interest with high signal intensity on ASL and CE+T1WI were defined using three dimensional analysis software. Tumor volume difference (ASL-CE) and tumor volume ratio (ASL/CE) were obtained. Absolute maximal tumor blood flow (TBF) and TBF ratio (normalized to white matter) were also measured. The Mann-Whitney U test and receiver operating characteristic curve analysis were performed to compare measurements between the tumor groups. Both tumor volume difference and tumor volume ratio were significantly higher in GBM than in metastasis. Both TBF and TBF ratio were higher for GBM than for metastasis, but the differences were not significant. The difference in tumor volume as measured by ASL high signal intensity and CE+T1WI might be useful for differentiating GBM from metastasis, whereas ASL-derived TBF is insufficient. J. Med. Invest. 64: 58-63, February, 2017.

Automatic metastatic brain tumor segmentation for stereotactic radiosurgery applications

The objective of this study is to develop an automatic segmentation strategy for efficient and accurate metastatic brain tumor delineation on contrast-enhanced T1-weighted (T1c) magnetic resonance images (MRI) for stereotactic radiosurgery (SRS) applications. The proposed four-step automatic brain metastases segmentation strategy is comprised of pre-processing, initial contouring, contour evolution, and contour triage. First, T1c brain images are preprocessed to remove the skull. Second, an initial tumor contour is created using a multi-scaled adaptive threshold-based bounding box and a super-voxel clustering technique. Third, the initial contours are evolved to the tumor boundary using a regional active contour technique. Fourth, all detected false-positive contours are removed with geometric characterization. The segmentation process was validated on a realistic virtual phantom containing Gaussian or Rician noise. For each type of noise distribution, five different noise levels were tested. Twenty-one cases from the multimodal brain tumor image segmentation (BRATS) challenge dataset and fifteen clinical metastases cases were also included in validation. Segmentation performance was quantified by the Dice coefficient (DC), normalized mutual information (NMI), structural similarity (SSIM), Hausdorff distance (HD), mean value of surface-to-surface distance (MSSD) and standard deviation of surface-to-surface distance (SDSSD). In the numerical phantom study, the evaluation yielded a DC of 0.98 ± 0.01, an NMI of 0.97 ± 0.01, an SSIM of 0.999 ± 0.001, an HD of 2.2 ± 0.8 mm, an MSSD of 0.1 ± 0.1 mm, and an SDSSD of 0.3 ± 0.1 mm. The validation on the BRATS data resulted in a DC of 0.89 ± 0.08, which outperform the BRATS challenge algorithms. Evaluation on clinical datasets gave a DC of 0.86 ± 0.09, an NMI of 0.80 ± 0.11, an SSIM of 0.999 ± 0.001, an HD of 8.8 ± 12.6 mm, an MSSD of 1.5 ± 3.2 mm, and an SDSSD of 1.8 ± 3.4 mm when comparing to the physician drawn ground truth. The result indicated that the developed automatic segmentation strategy yielded accurate brain tumor delineation and presented as a useful clinical tool for SRS applications.

C2 dumbbell-shaped peripheral nerve sheath tumors: Surgical management and relationship with venous structures

ObjectivesThis study focuses on the adjacent venous structures of tumors and their treatment in patients with second cervical (C2) dumbbell-shaped peripheral nerve sheath tumors (PNSTs). Patients and methodsThe authors retrospectively analyzed the clinical outcome and the venous structures involved with tumors in 16 patients with C2 dumbbell-shaped PNSTs treated surgically between 2008 and 2015. ResultsThe venous structures at the craniocervical junction could be visualized in all 16 patients on contrast-enhanced T1-weighted magnetic resonance imaging. The venous structures could be identified during surgery. The common locations of venous structures were noted as follows: the suboccipital cavernous sinus was located anterolateral and toward the top of the tumor; the vertebral venous plexus was located ventral to the tumor; and the vertebral artery venous plexus was shifted anteriorly and laterally by the tumor. Total excision was achieved in all 16 patients. Clinical improvements were observed in all 16 patients postoperatively. ConclusionsThe C2 dumbbell-shaped PNSTs were closely related to the suboccipital venous structures. Understanding and proper management of these venous structures is critical for reduced bleeding and successful surgery.

Signal intensity ratio on magnetic resonance imaging as a prognostic factor in patients with cervical compressive myelopathy.

Patients with intramedullary signal intensity (SI) changes have a poor prognosis after surgical decompression in cervical compressive myelopathy (CCM); however, some patients show no clear relationship between the SI and postsurgical prognosis. This discrepancy may be because no comprehensive and proper quantitative evaluation exists to assess SI on magnetic resonance imaging (MRI). The purpose of this study was prospectively to evaluate the correlation between the clinical features, neurological outcome of patients with CCM, and the quantitative assessment of SI changes preoperatively and postoperatively, and the correlation with SI severity.A total of 112 patients with CCM at 1 or 2 levels underwent anterior cervical discectomy and fusion. We quantitatively analyzed MR signal changes on T1-weighted MR images (T1WI), gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) contrast-enhanced T1WI, and T2-weighted MR images (T2WI) using the signal intensity ratio (SIR). We evaluated the correlations between various variables and neurological outcome using the Japanese Orthopedic Association (JOA) scale, and the severity of SI change by grade (i.e., grade 0 ["none"], grade 1 ["light"], and grade 2 ["bright on T2WI"]).Significant differences between the 3 grades existed in symptom duration, preoperative JOA score, SIR on T2WI, and JOA recovery ratio. The JOA recovery ratio was negatively correlated with symptom duration and the SIR on T2WI, and positively correlated with the preoperative JOA score and cord compression ratio, but not with the SIR on T1WI and contrast-enhanced T1WI. On the postoperative 12-month follow-up MRI, the JOA recovery ratio and SIR on T2WI of the SI reversal patients were better than those of the nonreversal patients. On multiple regression analysis, the SIR on T2WI was the main significant prognostic factor of surgical outcome.The grading system on T2WI provided reliable predictive information for neurological outcome. Quantitative alterations in the SI on preoperative and postoperative T2WI, but not T1WI or contrast-enhanced T1WI, reflected the clinical features, surgical outcomes, and the correlation with SI severity. The patients with a longer duration of symptoms, lower cord compression ratio, severe myelopathy, intense signal change (i.e., grade 2) on the spinal cord, and an SIR greater than 1.55 had a poor recovery after a surgical operation.

Growth inhibition in a brain metastasis model by antibody delivery using focused ultrasound-mediated blood-brain barrier disruption

HER2-targeting antibodies (i.e. trastuzumab and pertuzumab) prolong survival in HER2-positive breast cancer patients with extracranial metastases. However, the response of brain metastases to these drugs is poor, and it is hypothesized that the blood-brain barrier (BBB) limits drug delivery to the brain. We investigated whether we could improve the response by temporary disruption of the BBB using focused ultrasound in combination with microbubbles. To study this, we inoculated 30 nude rats with HER2-positive cells derived from a brain metastasis of a breast cancer patient (MDA-MB-361). The animals were divided into three groups: a control-group that received no treatment; an antibody-only group that received six weekly treatments of trastuzumab and pertuzumab; and an ultrasound+antibody group that received trastuzumab and pertuzumab in combination with six weekly sessions of BBB disruption using focused ultrasound. In two animals, the leakiness of the tumors before disruption was evaluated using contrast-enhanced T1-weighted magnetic resonance imaging and found that the tumors were not leaky. The same technique was used to evaluate the effectiveness of BBB disruption, which was successful in all sessions.The tumor in the control animals grew exponentially with a growth constant of 0.042±0.011mm3/day. None of the antibody-only animals responded to the treatment and the growth constant was 0.033±0.009mm3/day during the treatment period. Four of the ten animals in the ultrasound+antibody-group showed a response to the treatment with an average growth constant of 0.010±0.007mm3/day, compared to a growth constant 0.043±0.013mm3/day for the six non-responders. After the treatment period, the tumors in all groups grew at similar rates. As the tumors were not leaky before BBB disruption and there were no responders in the antibody-only group, these results show that at least in some cases disruption of the BBB is necessary for a response to the antibodies in these brain metastases. Interestingly, only some of the rats responded to the treatment. We did not observe a difference in tumor volume at the start of the treatment, nor in HER2 expression or in contrast-enhancement on MRI between the responders and non-responders to explain this. Better understanding of why certain animals respond is needed and will help in translating this technique to the clinic. In conclusion, we demonstrate that BBB disruption using focused ultrasound in combination with antibody therapy can inhibit growth of breast cancer brain metastasis.

Bioluminescence and MR Imaging of the Safety and Efficacy of Vascular Disruption in Gliomas.

The goal of the present study was to examine the safety and efficacy of the vascular disrupting agent (VDA) EPC2407 (Crolibulin™) in experimental glioma models using bioluminescence imaging (BLI) and magnetic resonance imaging (MRI). Experimental imaging studies were performed in subcutaneous human U87 glioma xenografts and orthotopic murine gliomas established by intracranial implantation of luciferase-transfected glioma cells (GL261-luc). Correlative histopathology and long-term survival analysis was also performed. Treatment with EPC2407 decreased tumor perfusion and increased necrosis and tumor doubling times in subcutaneous U87 xenografts. Dynamic BLI and T1-weighted contrast-enhanced MRI showed reduction in blood flow of intracranial GL261-luc gliomas within a few hours of VDA treatment. T2-weighted MRI did not show any evidence of hemorrhaging or edema in uninvolved brain tissue of EPC2407-treated animals. A significant increase in median survival (p < 0.05) was observed in the orthotopic GL261-luc model following VDA treatment compared to untreated controls. We demonstrate, for the first time, the biological activity of EPC2407 in experimental gliomas. Further investigation into the potential of VDAs in combination with chemoradiation therapy against gliomas is warranted.

Effect of gadolinium contrast-enhanced T1-weighted magnetic resonance imaging for detecting extramural venous invasion in rectal cancer.

To evaluate the performance of gadolinium contrast-enhanced T1-weighted magnetic resonance imaging (CET1WI) in addition to high-resolution T2-weighted imaging (HRT2WI) for preoperative detection of extramural venous invasion (EMVI) in rectal cancer. Fifty-nine patients with rectal cancer who underwent preoperative MRI were included in this study. The likelihood of EMVI was retrospectively scored by two readers on CET1WI, HRT2WI, and HRT2WI+CET1WI, using a subjective five-point scale ranging from 0 to 4. The pathological status of EMVI was used as a standard reference. Diagnostic parameters, including area under the receiver operating curve (AUC), sensitivity, and specificity, were calculated, and the diagnostic performances of HRT2WI and HRT2WI+CET1WI were compared. Interobserver variance was also evaluated. Eighteen (30.5%) patients showed pathological EMVI. During EMVI detection, reader A obtained an AUC of 0.768, sensitivity of 72.5%, and specificity of 73.2% from HRT2WI alone; after combination with CET1WI, these values improved to 0.864, 83.3%, and 75.6%, respectively. Differences in AUC between these techniques were not significant (p=0.056). Reader B obtained an AUC of 0.833, sensitivity of 77.8%, and specificity of 73.2% from HRT2WI alone; after combination with CET1W1, these figures were adjusted to 0.720, 50%, and 78%; differences in AUC between techniques were significant (p=0.027). Interobserver agreement during EMVI scoring was good for HRT2WI (κ=0.603) and moderate for HRT2WI+CET1WI (κ=0.413). Although interobserver agreement decreased, combination of CET1WI with HRT2WI could improve EMVI detection.

Brain Metastases Detection Algorithms in Magnetic Resonance Imaging

Early detection of brain metastases increases survival in patients with cancer, since image-guided radiosurgery is the most widely used treatment. As support for the qualitative diagnosis made by radiologists, Computer Assisted Diagnosis provides a quantitative and reproducible analysis. This article reviews the methods for an automatic detection of brain metastases in contrast-enhanced T1-weighted magnetic resonance imaging. Model-based methods detect metastases due to their high degree of similarity with models representing their morphology, mainly templates. On the other hand, methods based on brain symmetry and intensity search intensity differences between both brain hemispheres with respect to the symmetry axis. Model-based methods are more commonly used because they allow the detection of metastases of a wider range of measures.

Acute Myositis of the Tibialis Anterior Muscle after Performance of 108 Prostrations

Exercise-induced muscle damage (EIMD) can be caused by novel or unaccustomed exercise resulting in a temporary decrease in muscle function, increased muscle soreness and swelling, and an increase in muscle proteins in blood. A 38-year-old female presented with a 2-week history of bilateral lower leg pain and swelling that developed suddenly after performing 108 prostrations. Fat-suppressed contrastenhanced T1-weighted magnetic resonance imaging showed bilateral symmetric high signal intensity of the tibialis anterior muscles. Our patient was diagnosed with acute myositis and treated with naproxen. History of physical exertion and acute onset of typical clinical findings of myositis were key elements in the diagnosis. Acute myositis related to exercise is a common and self-limiting condition which fully resolves after 2 to 3 weeks. However, other causes of myositis should be excluded in patients with atypical clinical features.

Assessment the Optimal Effect of Time of Repetition: Extrinsic Pulse Parameter on Gd-DTPA Enhanced, Spin-Echo T1-Weighted MR Images under Low Magnetic Field Strength

The contrast agent concentration, the time of repetition (TR) and magnetic field strength are significant parameters that influence for the accurate signal intensity (SI) in quantitative Magnetic Resonance Imaging (MRI). Therefore, this study was conducted to investigate and refine the dependence and the optimal effect of Time of Repetition (TR) on the relationship between signal intensity and Gd-DTPA (Gadolinium-diethylene-triaminepenta-acetic acid) concentration, after applying two-dimensional (2D) Spin Echo (SE) pulse sequence under low-field MRI. In addition to that, the optimal concentration of Gd-DTPA at given sequence parameters at low-field MRI was also evaluated. A water-filled phantom was constructed for a range of Gd-DTPA concentrations (0 - 6 mmol/L) and the mean signal intensities (SIs) were assessed in the defined region of interest on T1-weighted images with different TR values (40 - 2000 ms). The generated signal-concentration curves for Gd-DTPA revealed that increasing TR was associated with the increase of the overall SIs and the maximum relationship between SI to concentration. Moreover, the required Gd-DTPA concentration to produce the maximum SI was associated to decrease with the increase of TR. In addition to this, the application of beyond 100 ms TR values in this study with relatively higher concentrations (beyond 1 - 2 mmol/L) has resulted predominantly non-linear patterns in the signal-concentration curves and it appears the saturation or decay of the SIs due to T2 effect. From these results, it can be suggested that the selection of relatively lower Gd-DTPA concentration ( mmol/L) with less than 800 ms (<800 ms) TR values can produce a better linear relationship between the concertation and SIs in T1-weighted SE low field contrast-enhanced MRI. Furthermore, this study also outlined the significance and necessity of the optimization of TR in SE sequence in low field MRI prior to a particular examination.

Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment.

To use magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU), magnetic resonance imaging (MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue. Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication (n = 24) using a 3T-MRg-HIFU (1.1 MHz frequency and 3000J-4400J energies). T2-weighted fast spin echo (T2-W), perfusion saturation recovery gradient echo and contrast enhanced (CE) T1-weighted (T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student's t-test was used and a P-value < 0.05 was considered statistically significant. Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or non-CE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images in vivo (0.12-0.36 cm(3) for single sonication 3000J, 0.50-0.84 cm(3), for double 3000J, 0.75-0.78 cm(3) for single 4400J and 0.12-2.65 cm(3) for double 4400J) and at postmortem (0.23-0.52 cm(3), 0.25-0.82 cm(3), 0.45-0.68 cm(3) and 0.29-1.80 cm(3), respectively) were comparable. The ablated volumes on 3000J and 4400J double sonication were significantly larger than single (P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively. Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI.

Texture Analysis of T2-Weighted MR Images to Assess Acute Inflammation in Brain MS Lesions

Brain blood barrier breakdown as assessed by contrast-enhanced (CE) T1-weighted MR imaging is currently the standard radiological marker of inflammatory activity in multiple sclerosis (MS) patients. Our objective was to evaluate the performance of an alternative model assessing the inflammatory activity of MS lesions by texture analysis of T2-weighted MR images. Twenty-one patients with definite MS were examined on the same 3.0T MR system by T2-weighted, FLAIR, diffusion-weighted and CE-T1 sequences. Lesions and mirrored contralateral areas within the normal appearing white matter (NAWM) were characterized by texture parameters computed from the gray level co-occurrence and run length matrices, and by the apparent diffusion coefficient (ADC). Statistical differences between MS lesions and NAWM were analyzed. ROC analysis and leave-one-out cross-validation were performed to evaluate the performance of individual parameters, and multi-parametric models using linear discriminant analysis (LDA), partial least squares (PLS) and logistic regression (LR) in the identification of CE lesions. ADC and all but one texture parameter were significantly different within white matter lesions compared to within NAWM (p < 0.0167). Using LDA, an 8-texture parameter model identified CE lesions with a sensitivity Se = 70% and a specificity Sp = 76%. Using LR, a 10-texture parameter model performed better with Se = 86% / Sp = 84%. Using PLS, a 6-texture parameter model achieved the highest accuracy with Se = 88% / Sp = 81%. Texture parameter from T2-weighted images can assess brain inflammatory activity with sufficient accuracy to be considered as a potential alternative to enhancement on CE T1-weighted images.

Application of contrast-enhanced T1-weighted MRI-based 3D reconstruction of the dural tail sign in meningioma resection.

OBJECT The goal of this study was to investigate the significance of contrast-enhanced T1-weighted (T1W) MRI-based 3D reconstruction of dural tail sign (DTS) in meningioma resection. METHODS Between May 2013 and August 2014, 18 cases of convexity and parasagittal meningiomas showing DTS on contrast-enhanced T1W MRI were selected. Contrast-enhanced T1W MRI-based 3D reconstruction of DTS was conducted before surgical treatment. The vertical and anteroposterior diameters of DTS on the contrast-enhanced T1W MR images and 3D reconstruction images were measured and compared. Surgical incisions were designed by referring to the 3D reconstruction and MR images, and then the efficiency of the 2 methods was evaluated with assistance of neuronavigation. RESULTS Three-dimensional reconstruction of DTS can reveal its overall picture. In most cases, the DTS around the tumor is uneven, whereas the DTS around the dural vessels presents longer extensions. There was no significant difference (p > 0.05) between the vertical and anteroposterior diameters of DTS measured on the contrast-enhanced T1W MR and 3D reconstruction images. The 3D images of DTS were more intuitive, and the overall picture of DTS could be revealed in 1 image, which made it easier to design the incision than by using the MR images. Meanwhile, assessment showed that the incisions designed using 3D images were more accurate than those designed using MR images (ridit analysis by SAS, F = 7.95; p = 0.008). Pathological examination showed that 34 dural specimens (except 2 specimens from 1 tumor) displayed tumor invasion. The distance of tumor cell invasion was 1.0-21.6 mm (5.4 ± 4.41 mm [mean ± SD]). Tumor cell invasion was not observed at the dural resection margin in all 36 specimens. CONCLUSIONS Contrast-enhanced T1W MRI-based 3D reconstruction can intuitively and accurately reveal the size and shape of DTS, and thus provides guidance for designing meningioma incisions.

Values of apparent diffusion coefficients in staging the lesions of multiple sclerosis

Objective To explore the values of apparent diffusion coefficients(ADC) in staging the lesions of multiple sclerosis(MS) through analysing the differences of ADC in different types of lesions. Methods 137 lesions identified in 29 patients with MS, were characterized by their enhancement pattern on contrast-enhanced T1-weighted MR images and whether they were changing in appearance, size or signal. The lesions were classified into four groups: homogeneously enhancing lesions (HELs), ring-enhancing lesions (RELs), active nonenhancing lesions (ANELs), and inactive nonenhancing lesions(INELs). The mean ADC values for each type of lesions were calculated and compared. Results The ADC values for HELs, RELs, ANELs and INELs were (91.09±13.63)×10-5·m2·s-1, (105.66±9.92)×10-5·m2·s-1, (136.80±20.31)×10-5·m2·s-1 and (127.46±13.65)×10-5·m2·s-1. There were significant differences between the ADC values of any two groups in the four groups except the ADC values between ANELs and INELs. Conclusion ADC values are useful to differentiate each type of lesion, which can help stage the lesions of MS. Key words: Multiple sclerosis; Lesion staging; Apparent diffusion coefficients; Diffusion-weighted imaging

Imaging Inflammation in Cerebrovascular Disease.

Imaging inflammation in large intracranial artery pathology may play an important role in the diagnosis of and risk stratification for a variety of cerebrovascular diseases. Looking beyond the lumen has already generated widespread excitement in the stroke community, and the potential to unveil molecular processes in the vessel wall is a natural evolution to develop a more comprehensive understanding of the pathogenesis of diseases, such as ICAD and brain aneurysms.

Contrast-enhanced MRI of the knee in children unaffected by clinical arthritis compared to clinically active juvenile idiopathic arthritis patients.

ObjectivesTo evaluate enhancing synovial thickness upon contrast-enhanced magnetic resonance imaging (MRI) of the knee in children unaffected by clinical arthritis compared with clinically active juvenile idiopathic arthritis (JIA) patients. A secondary objective was optimization of the scoring method based on maximizing differences on MRI between these groups.MethodsTwenty-five children without history of joint complaints nor any clinical signs of joint inflammation were age/sex-matched with 25 clinically active JIA patients with arthritis of at least one knee. Two trained radiologists, blinded for clinical status, independently evaluated location and extent of enhancing synovial thickness with the validated Juvenile Arthritis MRI Scoring system (JAMRIS) on contrast-enhanced axial fat-saturated T1-weighted MRI of the knee.ResultsEnhancing synovium (≥2 mm) was present in 13 (52 %) unaffected children. Using the total JAMRIS score for synovial thickening, no significant difference was found between unaffected children and active JIA patients (p = 0.091). Additional weighting of synovial thickening at the JIA-specific locations enabled more sensitive discrimination (p = 0.011).ConclusionsMild synovial thickening is commonly present in the knee of children unaffected by clinical arthritis. The infrapatellar and cruciate ligament synovial involvement were specific for JIA, which—in a revised JAMRIS—increases the ability to discriminate between JIA and unaffected children.Key Points• Synovial inflammation is the primary disease feature in juvenile idiopathic arthritis (JIA).• Appearance of the synovium on contrast-enhanced MRI in unaffected children is unknown.• Validation of existing scoring methods requires comparison between JIA and unaffected children.• Mild enhancing synovial thickening was detected in half of the unaffected children.• Location-weighting for JIA-specific locations increased discriminative value of the scoring methods (p = 0.011).Electronic supplementary materialThe online version of this article (doi:10.1007/s00330-015-3912-z) contains supplementary material, which is available to authorized users.

Somatostatin receptor subtype 2 in high-grade gliomas: PET/CT with (68)Ga-DOTA-peptides, correlation to prognostic markers, and implications for targeted radiotherapy.

BackgroundHigh-grade gliomas (HGGs) express somatostatin receptors (SSTR), rendering them candidates for peptide receptor radionuclide therapy (PRRT). Our purpose was to evaluate the potential of 68Ga-DOTA-1-Nal3-octreotide (68Ga-DOTANOC) or 68Ga-DOTA-Tyr3-octreotide (68Ga-DOTATOC) to target SSTR subtype 2 (SSTR2) in HGGs, and to study the association between SSTR2 expression and established biomarkers.MethodsTwenty-seven patients (mean age 52 years) with primary or recurrent HGG prospectively underwent 68Ga-DOTA-peptide positron emission tomography/computed tomography (PET/CT) before resection. Maximum standardized uptake values (SUVmax) and receptor binding potential (BP) were calculated on PET/CT and disruption of blood–brain barrier (BBB) from contrast-enhanced T1-weighted magnetic resonance imaging (MRI-T1-Gad). Tumor volume concordance between PET and MRI-T1-Gad was assessed by Dice similarity coefficient (DC) and correlation by Spearman’s rank. Immunohistochemically determined SSTR2 status was compared to receptor imaging findings, prognostic biomarkers, and survival with Kruskal-Wallis, Pearson chi-square, and multivariate Cox regression, respectively.ResultsAll 19 HGGs with disrupted BBB demonstrated tracer uptake. Tumor SUVmax (2.25 ± 1.33) correlated with MRI-T1-Gad (r = 0.713, P = 0.001) although DC 0.41 ± 0.19 suggested limited concordance. SSTR2 immunohistochemistry was regarded as positive in nine HGGs (32%) but no correlation with SUVmax or BP was found. By contrast, SSTR2 expression was associated with IDH1 mutation (P = 0.007), oligodendroglioma component (P = 0.010), lower grade (P = 0.005), absence of EGFR amplification (P = 0.021), and longer progression-free survival (HR 0.161, CI 0.037 to 0.704, P = 0.015).ConclusionsIn HGGs, uptake of 68Ga-DOTA-peptides is associated with disrupted BBB and cannot be predicted by SSTR2 immunohistochemistry. Thus, PET/CT shows limited value to detect HGGs suitable for PRRT. However, high SSTR2 expression portends favorable outcome along with established biomarkers such as IDH1 mutation.Trial registrationClinicalTrials.gov NCT01460706