New observations concerning the interpretation of magnetic resonance spectroscopy of meningioma

This study was aimed to clarify some ambiguities in the interpretation of proton magnetic resonance spectroscopy (1H-MRS) of meningiomas. The cases of 31 meningioma patients (27 benign and 4 nonbenign meningiomas) that underwent single-voxel 1H-MRS (PRESS sequence, TR/TE = 2,000 ms/68, 136, 272 ms) were retrospectively analyzed. To verify the findings of in-vivo study, phantoms were measured, and pathological sections of 11 patients were reviewed. All meningiomas demonstrated increased choline and decreased creatine, except for a lipomatous meningioma that only displayed a prominent lipid (Lip) peak. Alanine (Ala) and lactate (Lac) coexisted in eight cases, indicating an alternative pathway of energy metabolism in meningiomas. They partially overlapped with each other and demonstrated a triplet-like spectral pattern, which was consistent with phantom study. Glutamine/glutamate (Glx) was helpful for the recognition of meningioma when Ala was absent. N-acetyl compounds(NACs) were observed in nine cases whose voxels were completely limited within the tumors, indicating that meningiomas might have endogenous NACs. Lac was indicative of an aggressive meningioma, although not always a nonbenign one. Lip not only represented micronecrosis in nonbenign meningiomas, but also reflected microcystic changes or fatty degeneration in benign meningiomas. 1H-MRS reflects some distinctive biochemical and pathological changes of meningiomas that might be misinterpreted. Grant: This study was supported by the Japan-China Sasakawa Medical Fellowship (Nippon Foundation, Japan)     

Single voxel proton MR spectroscopy findings of typical and atypical intracranial meningiomas

PURPOSE: To prospectively define proton magnetic resonance spectroscopy (MRS) findings of meningiomas, and describe the ability or inability of short- and long-echo MRS to differentiate typical and atypical meningiomas in vivo. MATERIAL AND METHODS: Seventeen patients with pathologically confirmed typical meningiomas and six with atypical meningiomas were evaluated with conventional MR imaging and MRS before resection. MRS studies using point-resolved spectroscopy (PRESS) localisation, at short- and long-echo time (TR 2000 ms, TE: 30 and 144 ms, 64-96 acquisition) were acquired on a 1.5 T scanner. MRS data obtained from these patients were compared with histopathological findings. Mean cellular proliferation (MIB-1) antibody staining against the Ki-67 antigen was also determined in all meningiomas. RESULTS: Prominent choline (Cho) was present in all meningiomas. Alanine (Ala) was observed in 21 cases of the 23 meningiomas. Acetylaspartate (NAA) and creatine (Cr) were either not observed or detected in minimal amounts in at all both groups of meningiomas on long TE (144 ms) spectra. The mean Cho/Cr values in the four atypical meningiomas were 4.44+/-0.30 (mean+/-standard deviation) and 3.39+/-0.52 in the 12 typical meningiomas on short TE spectra. Cho/Cr ratio could not be determined in the other seven cases because of a lack of creatine peak. Of the five meningiomas in which a lactate peak was detected, four were in typical cases and only one was in atypical meningioma. Mean MIB-1 proliferation index was 3.7% in typical meningiomas and 10% in atypical meningiomas. CONCLUSION: Prominent Cho, absence or low amount of NAA and Cr, and presence of Ala were common characteristics of spectral pattern of both atypical and typical meningiomas on MRS. MRS cannot reliably differentiate typical intracranial meningiomas from atypical meningiomas preoperatively. Mean MIB-1 proliferation index was well correlated with histopathology findings.     

Preoperative subtyping of meningiomas by perfusion MR imaging

Introduction  This paper aims to evaluate the value of perfusion magnetic resonance (MR) imaging in the preoperative subtyping of meningiomas by analyzing the relative cerebral blood volume (rCBV) of three benign subtypes and anaplastic meningiomas separately. Materials and methods  Thirty-seven meningiomas with peritumoral edema (15 meningothelial, ten fibrous, four angiomatous, and eight anaplastic) underwent perfusion MR imaging by using a gradient echo echo-planar sequence. The maximal rCBV (compared with contralateral normal white matter) in both tumoral parenchyma and peritumoral edema of each tumor was measured. The mean rCBVs of each two histological subtypes were compared using one-way analysis of variance and least significant difference tests. A p value less than 0.05 indicated a statistically significant difference. Results  The mean rCBV of meningothelial, fibrous, angiomatous, and anaplastic meningiomas in tumoral parenchyma were 6.93 ± 3.75, 5.61 ± 4.03, 11.86 ± 1.93, and 5.89 ± 3.85, respectively, and in the peritumoral edema 0.87 ± 0.62, 1.38 ± 1.44, 0.87 ± 0.30, and 3.28 ± 1.39, respectively. The mean rCBV in tumoral parenchyma of angiomatous meningiomas and in the peritumoral edema of anaplastic meningiomas were statistically different (p < 0.05) from the other types of meningiomas. Conclusion  Perfusion MR imaging can provide useful functional information on meningiomas and help in the preoperative diagnosis of some subtypes of meningiomas.     

Studying neonatal bilirubin encephalopathy with conventional MRI,MRS, and DWI

Introduction  The purpose of this study was to evaluate the diagnostic value of conventional magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy (¹H-MRS), and diffusion-weighted imaging (DWI) for neonatal bilirubin encephalopathy. Methods  We collected conventional MRI in 24 neonates with neonatal bilirubin encephalopathy. We performed ¹H-MRS and DWI sequences to nine of the 24 patients and seven age-matched healthy control subjects. Multiple-voxel ¹H-MRS data were acquired using PRESS pulse sequence with TE = 135 ms and TR = 1500 ms. The spectroscopic regions of interest were the bilateral basal ganglia and thalamus with a 1.0 mL spatial resolution. The data from DWI were collected by using a single shot-spin echo-echo planar imaging sequence with TR/TE: 2900/98, and imaging regions were also focused on the bilateral basal ganglia and thalamus. Results  Nineteen of the 24 patients had abnormal T₁-weighted image hyperintensity in the globus pallidus, but these lesions appeared as normal T₂-weighted image intensity in the same region. Ten of the 24 patients had T₁-weighted image high signal intensity in the subthalamic nucleus and appeared as normal intensity in the region for the T₂-weighted images. The peak area ratios of NAA/Cho and NAA/Cr were significantly decreased (t-test, P < 0.05) in the patients compared to the controls in the basal ganglia. Conclusion  Conventional MR imaging and ¹H-MRS are important complementary tools in the diagnosis of neonatal bilirubin encephalopathy. The study provides important information for applying these MR modalities to evaluate neonates with bilirubin encephalopathy.     

Peritumoral edema of meningiomas and metastatic brain tumors: differences in diffusion characteristics evaluated with diffusion-tensor MR imaging

Introduction We prospectively compared the fractional anisotropy (FA) and mean diffusivity (MD) of the peritumoral edema of meningiomas and metastatic brain tumors with diffusion-tensor magnetic resonance (MR) imaging. Methods The study protocol was approved by the local ethics committee, and written informed consent was obtained. Preoperative diffusion-tensor MR imaging was performed in 15 patients with meningiomas and 11 patients with metastatic brain tumors. Regions of interest (ROI) were placed in the peritumoral edema and normal-appearing white matter (NAWM) of the contralateral hemisphere to measure the FA and MD. The FA and MD ratios were calculated for each ROI in relation to the NAWM of the contralateral hemisphere. Changes in peritumoral MD and FA, in terms of primary values and ratios, were compared using a two-sample t-test; P < 0.05 was taken as indicating statistical significance. Results The mean MD values (×10⁻³ mm²/s) of the peritumoral edema for metastases and meningiomas, respectively, were 0.902 ± 0.057 and 0.820 ± 0.094, the mean MD ratios were 220.3 ± 22.6 and 193.1 ± 23.4, the mean FA values were 0.146 ± 0.026 and 0.199 ± 0.052, and the mean FA ratios were 32.3 ± 5.9 and 46.0 ± 12.1. All the values were significantly different between metastases and meningiomas (MD values P = 0.016, MD ratios P = 0.006, FA values P = 0.005, FA ratios P = 0.002). Conclusion The peritumoral edema of metastatic brain tumors and meningiomas show different MD and FA on diffusion-tensor MR imaging.     

<Superscript>18</Superscript>F-FDG PET analysis of schwannoma: increase of SUVmax in the delayed scan is correlated with elevated VEGF/VPF expression in the tumors

Objective  In order to clarify the increased 2-deoxy-2-fluoro-¹⁸F-d-glucopyranose (¹⁸F-FDG) accumulation in schwannoma by positron emission tomography (PET) analysis, immunohistochemical analysis for the factors involved in glucose transportation and vascular formation was performed. Materials and methods  Twenty-six patients with schwannoma (13 men and 13 women) with ages ranging from 27 to 75 years, who received whole body ¹⁸F-FDG PET scan, were enrolled for the present study. The retention index (RI) was calculated by dividing the increase in the standardized uptake value (SUVmax) at the delayed scan by the SUVmax in the early scan. SUVmax and RI were compared with the histologic variables, including the expression of glucose transporters 1 and 3, hexokinase II, vascular endothelial growth factor/vascular permeability factor (VEGF/VPF), and microvascular density shown by CD31 immunohistochemistry. Results  Mean SUVmax values in the early and delayed scans were 2.64 ± 1.47 and 2.71 ± 1.57 (mean ± SD), respectively. RI was −2.5 ± 21 (percentage). SUVmax showed a positive correlation with the tumor size (tumor size <5 cm, 2.06 ± 0.72; >5 cm, 3.95 ± 1.89; p < 0.05) and the microvascular density (negative density, 2.16 ± 1.12; positive density, 3.56 ± 1.67; p < 0.05). RI correlated with VEGF/VPF expression in the tumors (negative expression, −11 ± 6.1; positive expression, 13 ± 8.1; p < 0.05). Other factors showed no correlation with SUVmax or RI. Conclusions  Microvascular density and vascular permeability of the tumor are suggested to affect the enhanced ¹⁸F-FDG accumulation in schwannoma.     

A practical predictor of the growth potential of benign meningiomas: Hypointensity of surface layer in T2-weighted magnetic resonance imaging

BackgroundAccurate evaluation of proliferative potential is particularly important in the clinical management of individual patients with meningiomas. We introduce a new feature in the parenchyma of meningioma, namely, hypointensity of the surface layer (HSL), on T2-weighted MR images and compare it with a cellular proliferation index and growth speed.Materials and methodsWe retrospectively analyzed the records of consecutive patients with WHO grade I meningiomas in two institutes: an operated group with 124 meningiomas resected in one institute, and an observed group with 89 meningiomas monitored without surgery in the other. Proliferative potential was evaluated using the MIB-1 labeling index (MIB-1 LI) for the operated group and using the relative growth rate on serial MR images for the observed group.ResultsIn the operated group, 60 (48.4%) meningiomas exhibited HSL. HSL-positive meningiomas were significantly smaller in size and more often calcified than HSL-negative ones. Univariate analysis showed that HSL negativity, large size, no calcification, and surrounding brain edema were significantly associated with high MIB-1 LI (p < 0.05). Multivariate analysis demonstrated that only HSL was significantly related to MIB-1 LI (p = 0.001). HSL did not correlate with tumor recurrence after resection. In the observed group, 43 (48.3%) meningiomas exhibited HSL and they presented a significantly slow relative growth rate.ConclusionsHSL is a simple and new radiological feature indicative of low proliferative potential and a low risk of enlargement of meningiomas. The presence or absence of HSL may serve as a key parameter for the selection of aggressive treatment or active observation.     

Structural alterations of the coronary arterial wall are associated with myocardial flow heterogeneity in type 2 diabetes mellitus

Purpose  To determine the relationship between carotid intima–media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM). Methods  In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined with electron beam tomography (EBT). Global and regional MBF was determined in milliliters per gram per minute with ¹³N-ammonia and positron emission tomography (PET) at rest, during cold pressor testing (CPT), and during adenosine (ADO) stimulation. Results  There was neither a relationship between carotid IMT and CAC (r = 0.10, p = 0.32) nor between carotid IMT and coronary circulatory function in response to CPT and during ADO (r = −0.18, p = 0.25 and r = 0.10, p = 0.54, respectively). In 33 individuals, EBT detected CAC with a mean Agatston-derived calcium score of 44 ± 18. There was a significant difference in regional MBFs between territories with and without CAC at rest and during ADO-stimulated hyperemia (0.69 ± 0.24 vs. 0.74 ± 0.23 and 1.82 ± 0.50 vs. 1.95 ± 0.51 ml/g/min; p ≤ 0.05, respectively) and also during CPT in DM but less pronounced (0.81 ± 0.24 vs. 0.83 ± 0.23 ml/g/min; p = ns). The increase in CAC was paralleled with a progressive regional decrease in resting as well as in CPT- and ADO-related MBFs (r = −0.36, p ≤ 0.014; r = −0.46, p ≤ 0.007; and r = −0.33, p ≤ 0.041, respectively). Conclusions  The absence of any correlation between carotid IMT and coronary circulatory function in type 2 DM suggests different features and stages of early atherosclerosis in the peripheral and coronary circulation. PET-measured MBF heterogeneity at rest and during vasomotor stress may reflect downstream fluid dynamic effects of coronary artery disease (CAD)-related early structural alterations of the arterial wall.     

Oral administration of choline does not affect metabolic characteristics of gliomas and normal-appearing white matter, as detected with single-voxel 1H-MRS at 1.5 T

Introduction  The present study was done for evaluation of the possible influence of the oral administration of choline on metabolic characteristics of gliomas detected with proton magnetic resonance spectroscopy (¹H-MRS). Materials and methods  Thirty patients (22 men and eight women; mean age 38 ± 15 years) with suspicious intracranial gliomas underwent single-voxel long-echo (TR 2,000 ms, TE 136 ms, 128–256 acquisitions) ¹H-MRS of the tumor, peritumoral brain tissue, and distant normal-appearing white matter before and several hours (median, 3 h; range, 1.2–3.7 h) after ingestion of choline with prescribed dose of 50 mg/kg (median actual dose, 52 mg/kg; range, 48–78 mg/kg). Investigations were done using 1.5 T clinical magnetic resonance imager. The volume of the rectangular ¹H-MRS voxel was either 3.4 or 8 cm³. At the time of both spectroscopic examinations, similar voxels’ positioning and size and technical parameters of ¹H-MRS were used. Surgery was done in 27 patients within 1 to 68 days thereafter. In all cases, more than 80% resection of the neoplasm was attained. Results  There were 12 low-grade gliomas and 15 high-grade gliomas. MIB-1 index varied from 0% to 51.7% (median, 13.8%). Statistical analysis did not disclose significant differences of any investigated metabolic parameter of the tumor, peritumoral brain tissue and distant normal-appearing white matter between two spectroscopic examinations. Conclusion  Single-voxel ¹H-MRS at 1.5 T could not detect significant changes of the metabolic characteristics of gliomas, peritumoral brain tissue, and distant normal-appearing white matter after oral administration of choline.     

Evaluation of right ventricular function with multidetector computed tomography: comparison with magnetic resonance imaging and analysis of inter- and intraobserver variability

This study was performed to prospectively compare multidetector computed tomography (MDCT) with 16 simultaneous sections and magnetic resonance imaging (MRI) for the assessment of global right ventricular function in 50 patients. MDCT using a semiautomatic analysis tool showed good correlation with MRI for end-diastolic volume (EDV, r = 0.83, p < 0.001), end-systolic volume (ESV, r = 0.86, p < 0.001) and stroke volume (SV, r = 0.74, p < 0.001), but only a moderate correlation for the ejection fraction (EF, r = 0.67, p < 0.001). Bland Altman analysis revealed a slight, but insignificant overestimation of EDV (4.0 ml, p = 0.08) and ESV (2.4 ml, p = 0.07), and underestimation of EF (0.1%, p = 0.92) with MDCT compared with MRI. All limits of agreement between both modalities (EF: ±15.7%, EDV: ±31.0 ml, ESV: ±18.0 ml) were in a moderate but acceptable range. Interobserver variability of MDCT was not significantly different from that of MRI. For MDCT software, the post-processing time was significantly longer (19.6 ± 5.8 min) than for MRI (11.8 ± 2.6 min, p < 0.001). Accurate assessment of right ventricular volumes by 16-detector CT is feasible but still rather time-consuming.     

Incidental head and neck <Superscript>18</Superscript>F-FDG uptake on PET/CT without corresponding morphological lesion: early predictor of cancer development?

Purpose  To retrospectively determine whether increased/asymmetric FDG uptake on PET without a correlating morphological lesion on fully diagnostic CT indicates the development of a head and neck malignancy. Methods  In 590 patients (mean age 55.4 ± 13.3 years) without a head and neck malignancy/inflammation FDG uptake was measured at (a) Waldeyer’s ring, (b) the oral floor, (c) the larynx, and (d) the thyroid gland, and rated as absent (group A), present (group B), symmetric (group B1) or asymmetric (group B2). Differences between groups A and B and between B1 and B2 were tested for significance with the U-test (p < 0.05). An average follow-up of about 2.5 years (mean 29.5 ± 13.9 months) served as the reference period to determine whether patients developed a head and neck malignancy. Results  Of the 590 patients, 235 (40%) showed no evidence of enhanced FDG uptake in any investigated site, and 355 (60%) showed qualitatively elevated FDG uptake in at least one site. FDG uptake values (SUV_max, mean±SD) for Waldeyer’s ring were 3.0 ± 0.89 in group A (n = 326), 4.5 ± 2.18 in group B (n = 264; p < 0.01), 5.4 ± 3.35 in group B1 (n = 177), and 4.1 ± 1.7 in group B2 (n = 87; p < 0.01). Values for the oral floor were 2.8 ± 0.74 in group A (n = 362), 4.7 ± 2.55 in group B (n = 228; p < 0.01), 4.4 ± 3.39 in group B1 (n = 130), and 5.1 ± 2.69 in group B2 (n = 98, p = 0.01). Values for the larynx were 2.8 ± 0.76 in group A (n = 353), 4.2 ± 2.05 in group B (n = 237; p < 0.01), 4.0 ± 2.02 in group B1 (n = 165), and 4.6 ± 2.8 in group B2 (n = 72; p = 0.027). Values for the thyroid were 2.4 ± 0.63 in group A (n = 404), 3.0 ± 1.01 in group B (n = 186; p < 0.01), 2.6 ± 0.39 in group B1 (n = 130), and 4.0 ± 1.24 in group B2 (n = 56; p < 0.01). One patient developed a palatine tonsil carcinoma (group B1, SUV_max 3.2), and one patient developed an oral floor carcinoma (group B1, SUV_max 3.7). Conclusion  Elevated/asymmetric head and neck FDG accumulation without a correlating morphological lesion can frequently be found and does not predict cancer development. In populations in which goitre is endemic, FDG uptake by the thyroid is common and not associated with thyroid cancer.     

Associations between the uptake of <Superscript>111</Superscript>In-DTPA-trastuzumab,HER2 density and response to trastuzumab (Herceptin) in athymic mice bearing subcutaneous human tumour xenografts

Purpose  The purpose of the study was to investigate the associations between uptake of ¹¹¹In-DTPA-trastuzumab, tumour HER2 density and response to trastuzumab (Herceptin) of human breast cancer (BC) xenografts in athymic mice. Materials and methods  The tumour uptake of ¹¹¹In-DTPA-trastuzumab in athymic mice bearing BC xenografts with increasing HER2 density (0 to 3+) was evaluated. Specific uptake ratios were established in biodistribution (SUR) and imaging studies (ROI-SUR) using ¹¹¹In-labeled mouse IgG (¹¹¹In-DTPA-mIgG). Further corrections were made for circulating radioactivity using tumour-to-blood ratios defined as a localization index (LI) and region-of-interest localization index (ROI-LI), respectively. Mice were treated with trastuzumab (Herceptin). A tumour growth inhibition index (TGI) was calculated and relative TGIs calculated by dividing the TGI of control by that of trastuzumab-treated mice. Results  Strong, nonlinear associations with HER2 density were obtained if the uptake of ¹¹¹In-DTPA-trastuzumab was corrected for nonspecific IgG localization (i.e., SUR; r ² = 0.99) and circulating radioactivity (i.e., LI; r ² = 0.87), but without these corrections, the association between HER2 density and tumour uptake was poor (r ² = 0.22). There was a strong association between ROI-SUR and ROI-LI values and HER2 expression (r ² = 0.90 and r ² = 0.95, respectively. All tumours were imaged. Relative TGI values were associated with increasing uncorrected tumour uptake of ¹¹¹In-DTPA-trastuzumab but not always with HER2 density (i.e., MCF-HER2-18 cells with trastuzumab-resistance). Conclusion  HER2 expression (0 to 3+) can be differentiated using ¹¹¹In-DTPA-trastuzumab, but requires correction of tumour uptake for nonspecific IgG localization and circulating radioactivity. The uncorrected uptake of ¹¹¹In-DTPA-trastuzumab was associated with tumour response to trastuzumab.     

Diffusion-weighted imaging and proton MR spectroscopy in the characterization of acute disseminated encephalomyelitis

Introduction Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. Methods Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). Results ADC values in NAWM were in the range 0.7–1.24×10⁻³ mm/s² (mean 0.937 ± 0.17 mm/s²). ADC values of ADEM lesions in the acute stage were in the range 0.37–0.68×10⁻³ mm/s² (mean 0.56 ± 0.16 mm/s²) and 1.01–1.31×10⁻³ mm/s² (mean 1.24 ± 0.13 mm/s²) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1–3.5 (mean 1.93 ± 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63–1.48 (mean 1.18 ± 0.48) and 0.29–0.84 (mean 0.49 ± 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). Conclusion ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios. Restricted diffusion and progressive decrease in NAA/Cho ratios may help in staging the disease.     

Deceleration in maturation of bone during adolescent age in achondroplasia—a retrospective study using RUS scoring system

Objectives  Knowledge of bone age in achondroplasia is required for the prediction of adult height, timings of limb lengthening, and epiphysiodesis procedures. The purpose of this investigation was to determine the differences in skeletal age in achondroplasia and a control population with the Tanner–Whitehouse 3 method using the RUS score and to determine the right age for the interventional procedure for limb lengthening procedure or deformity correction in these patients. Materials and methods  Left hand radiographs of 34 patients (age range, 5–18 years) with achondroplasia were evaluated for skeletal age using the RUS scoring system, which were compared with the left hand radiographs of 41 patients (age range, 5–18 years) without achondroplasia measuring skeletal age. The difference in chronological age and RUS bone age were evaluated statistically according to gender and age group. Results  In the achondroplasia group, chronological age were 10.5 ± 4.3 years for males and 10.1 ± 3.6 years for females and RUS bone age were 9.2 ± 4.0 years for males and 8.9 ± 3.4 years for females, which showed statistically significantly difference (males p = 0.0003 and females p < 0.0001), while in the control group, chronological age were 11.1 ± 2.9 years for males and 10.7 ± 3.4 years for females and RUS bone age were 11.2 ± 3.4 years for males and 10.7 ± 3.3 years for females, which did not show statistically significantly difference (males p = 0.54 and females p = 0.76). Our finding suggested a delay of 1.4 years for males and 1.2 years for females in the maturation of bone in achondroplasia patients. Difference between chronological age and RUS bone age was 0.9 ± 1.1 for <10 years and 1.6 ± 0.9 for >10 years in the study group, while 0.1 ± 1.1 for <10 years and −0.2 ± 0.6 for >10 years in the control group, which also showed >statistically significant difference (<10 years p = 0.04 and >10 years p < 0.0001). These differences indicate that there was a delay in the maturation of bones by 1 year in the group <10 years and 1.8 years in the group >10 years in achondroplasia patients compared to nonachondroplasia patients. Conclusion  We recommend the use of the Tanner–Whitehouse 3 method especially the radius, ulna, short bone score to measure the skeletal age and to wait for a longer time before interventional procedures in achondroplasia patients. Each author certifies that he has no commercial associations (e.g., consultancies, stock ownership, equity interests, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.     

MR elastography of liver fibrosis: preliminary results comparing spin-echo and echo-planar imaging

The purpose of this study was to prospectively compare the performance of magnetic resonance (MR) elastography using echo-planar and spin-echo imaging for staging of hepatic fibrosis. Twenty-four patients who had liver biopsy for suspicion of chronic liver disease had MR elastography performed with both spin-echo and echo-planar sequences. At histology, the fibrosis stage was assessed according to METAVIR. The data acquisition time was about 20 min using spin-echo, and only 2 min using echo-planar imaging. The hepatic signal-to-noise ratios were similar on both images (22.51 ± 5.37 for spin-echo versus 21.02 ± 4.76 for echo-planar, p = 0.33). The elasticity measurements and the fibrosis stages were strongly correlated. The Spearman correlation coefficients were r = 0.91 (p < 0.01) with spin-echo and r = 0.84 (p < 0.01) with echo-planar sequences. These correlation coefficients did not differ significantly (p = 0.17). A strong correlation was also observed between spin-echo and echo-planar elasticity (r = 0.83, p < 0.001), without systematic bias. The results of our study showed that echo-planar imaging substantially decreased the data acquisition time of MR elastography, while maintaining the image quality and diagnostic performance for staging of liver fibrosis. This suggests that echo-planar MR elastography could replace spin-echo MR elastography in clinical practice. This work was supported by grants FRSM 3.4578.00 and 3.4580.06 from the Fonds National de la Recherche Scientifique, Belgium.     

Utilization of glutamate/creatine ratios for proton spectroscopic diagnosis of meningiomas

Introduction Our purpose was to determine the potential of metabolites other than alanine to diagnose intracranial meningiomas on proton magnetic resonance spectroscopy (MRS). Methods Using a 1.5-T MR system the lesions were initially identified on FLAIR, and T1- and T2-weighted images. Employing standard point-resolved spectroscopy (PRESS) for single voxel proton MRS (TR 1500 ms, TE 30 ms, 128 acquisitions, voxel size 2 × 2 × 2 cm, acquisition time 3.12 min), MR spectra were obtained from 5 patients with meningiomas, from 20 with other intracranial lesions, and from 4 normal controls. Peak heights of nine resonances, including lipid, lactate, alanine, NAA (N-acetylaspartate), β/γ-Glx (glutamate + glutamine), creatine, choline, myo-inositol, and α-Glx/glutathione, were measured in all spectra. The relative quantity of each metabolite was measured as the ratio of its peak height to the peak height of creatine. Results Relative quantities of α-Glx/glutathione, β/γ-Glx, and total Glx/glutathione were significantly elevated in meningiomas compared to the 20 other intracranial lesions and the normal control brains. Alanine was found in four of five meningiomas, but lactate partially masked the alanine in three meningiomas. None of the other lesions or control brains showed an alanine peak. The one meningioma with no alanine and the three others with lactate had elevated Glx. Conclusion While alanine is a relatively unique marker for meningioma, our results support the hypothesis that the combination of glutamate/creatine ratios and alanine on proton MRS is more specific and reliable for the diagnosis of meningiomas than alanine alone.     

ACCURATUM: improved calcium volume scoring using a mesh-based algorithm—a phantom study

To overcome the limitations of the classical volume scoring method for quantifying coronary calcifications, including accuracy, variability between examinations, and dependency on plaque density and acquisition parameters, a mesh-based volume measurement method has been developed. It was evaluated and compared with the classical volume scoring method for accuracy, i.e., the normalized volume (measured volume/ground-truthed volume), and for variability between examinations (standard deviation of accuracy). A cardiac computed-tomography (CT) phantom containing various cylindrical calcifications was scanned using different tube voltages and reconstruction kernels, at various positions and orientations on the CT table and using different slice thicknesses. Mean accuracy for all plaques was significantly higher (p < 0.0001) for the proposed method (1.220 ± 0.507) than for the classical volume score (1.896 ± 1.095). In contrast to the classical volume score, plaque density (p = 0.84), reconstruction kernel (p = 0.19), and tube voltage (p = 0.27) had no impact on the accuracy of the developed method. In conclusion, the method presented herein is more accurate than classical calcium scoring and is less dependent on tube voltage, reconstruction kernel, and plaque density. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Infarct size in primary angioplasty without on-site cardiac surgical backup versus transferal to a tertiary center: a single photon emission computed tomography study

Background  Primary percutaneous coronary intervention (PCI) performed in large community hospitals without cardiac surgery back-up facilities (off-site) reduces door-to-balloon time compared with emergency transferal to tertiary interventional centers (on-site). The present study was performed to explore whether off-site PCI for acute myocardial infarction results in reduced infarct size. Methods and results  One hundred twenty-eight patients with acute ST-segment elevation myocardial infarction were randomly assigned to undergo primary PCI at the off-site center (n = 68) or to transferal to an on-site center (n = 60). Three days after PCI, ^99mTc-sestamibi SPECT was performed to estimate infarct size. Off-site PCI significantly reduced door-to-balloon time compared with on-site PCI (94 ± 54 versus 125 ± 59 min, respectively, p < 0.01), although symptoms-to-treatment time was only insignificantly reduced (257 ± 211 versus 286 ± 146 min, respectively, p = 0.39). Infarct size was comparable between treatment centers (16 ± 15 versus 14 ± 12%, respectively p = 0.35). Multivariate analysis revealed that TIMI 0/1 flow grade at initial coronary angiography (OR 3.125, 95% CI 1.17–8.33, p = 0.023), anterior wall localization of the myocardial infarction (OR 3.44, 95% CI 1.38–8.55, p < 0.01), and development of pathological Q-waves (OR 5.07, 95% CI 2.10–12.25, p < 0.01) were independent predictors of an infarct size > 12%. Conclusions  Off-site PCI reduces door-to-balloon time compared with transferal to a remote on-site interventional center but does not reduce infarct size. Instead, pre-PCI TIMI 0/1 flow, anterior wall infarct localization, and development of Q-waves are more important predictors of infarct size.     

<Superscript>11</Superscript>C-methionine (MET) and <Superscript>18</Superscript>F-fluorothymidine (FLT) PET in patients with newly diagnosed glioma

Purpose  The purpose of this prospective study was to clarify the individual and combined role of l-methyl-¹¹C-methionine-positron emission tomography (MET-PET) and 3′-deoxy-3′-[¹⁸F]fluorothymidine (FLT)-PET in tumor detection, noninvasive grading, and assessment of the cellular proliferation rate in newly diagnosed histologically verified gliomas of different grades. Materials and methods  Forty-one patients with newly diagnosed gliomas were investigated with MET-PET before surgery. Eighteen patients were also examined with FLT-PET. MET and FLT uptakes were assessed by standardized uptake value of the tumor showing the maximum uptake (SUV_max), and the ratio to uptake in the normal brain parenchyma (T/N ratio). All tumors were graded by the WHO grading system using surgical specimens, and the proliferation activity of the tumors were determined by measuring the Ki-67 index obtained by immunohistochemical staining. Results  On semiquantitative analysis, MET exhibited a slightly higher sensitivity (87.8%) in tumor detection than FLT (83.3%), and both tracers were 100% sensitive for malignant gliomas. Low-grade gliomas that were false negative on MET-PET also were false negative on FLT-PET. Although the difference of MET SUV_max and T/N ratio between grades II and IV gliomas was statistically significant (P < 0.001), there was a significant overlap of MET uptake in the tumors. The difference of MET SUV_max and T/N ratio between grades II and III gliomas was not statistically significant. Low-grade gliomas with oligodendroglial components had relatively high MET uptake. The difference of FLT SUV_max and T/N ratio between grades III and IV gliomas was statistically significant (P < 0.01). Again, the difference of FLT SUV_max and T/N ratio between grades II and III gliomas was not statistically significant. Grade III gliomas with non-contrast enhancement on MR images had very low FLT uptake. In 18 patients who underwent PET examination with both tracers, a significant but relatively weak correlation was observed between the individual SUV_max of MET and FLT (r = 0.54, P < 0.05) and T/N ratio of MET and FLT (r = 0.56, P < 0.05). Total FLT uptake in the tumor had a higher correlation (r = 0.89, P < 0.001) with Ki-67 proliferation index than MET uptake (r = 0.49, P < 0.01). Conclusions  PET studies using MET and FLT are useful for tumor detection in newly diagnosed gliomas. However, there is no complimentary information in tumor detection with simultaneous measurements of MET- and FLT-PET in low grade gliomas. FLT-PET seems to be superior than MET-PET in noninvasive tumor grading and assessment of proliferation activity in gliomas of different grades.