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Objectives: Recently, T1-weighted DCE-MRI was proposed as an alternative to T2*-weighted DSC-MRI for the quantification of perfusion and permeability in brain tumors. The aim of the present feasibility study was to explore the clinical potential of the technique in different tumor types using a case-based review of initial results. Patients and methods: The method for data analysis was adapted from cerebral perfusion CT and applied in this study to a small group of patients with grade IV glioma and other brain tumors. The possible use of the proposed methodology was also explored for characterizing, following-up and planning the therapy of brain tumors. Results: Parametric maps clearly differentiated tumor from the surrounding brain tissue, and also distinguished areas within the tumor presenting with different characteristics, thereby allowing identification of significant target areas for biopsy and/or treatment. Differences in cerebral blood flow (CBF) and lower extraction fractions (E) were observed in various tumors. Progression from a grade II to grade IV glioma over the course of a year was characterized by an increase in CBF and a decrease in E. Conclusion: DCE-MRI-based quantitative perfusion and permeability may be helpful for tumor-grade characterization, biopsy guidance, radiotherapy planning, radiotherapy monitoring and clinical follow-up, thereby improving the non-invasive characterization of brain tumors. (C) 2011 Elsevier Masson SAS. All rights reserved.

Transcranial magnetic stimulation (TMS) is currently used as a non-invasive treatment for depression. In most clinical trials, the left dorsolateral prefrontal cortex (DLPFC) has been selected as the target site for TMS treatment and this region is commonly determined by a "standard procedure", using a fixed position with respect to the motor cortex. In this study, to evaluate the relevance of using individual anatomical data during coil positioning, we used a more individualized localization method, based on three-dimensional magnetic resonance imaging of the head (3D-MRI). We wanted to examine the intra-individual variability of the localization of the stimulation area using a method taking into account individual brain anatomy by 3D-MRI, by comparing this method to the "standard procedure". As expected, even in a gender-controlled sample, our results demonstrate that the difference between the anatomical localization and the standard procedure of a well-defined part of the prefrontal cortex varies within subjects. Therefore, our results confirm the need for a TMS-coil positioning method which incorporates individual anatomical information.

The recent reports confirm the idea that the selection of cerebral stroke patients for thrombolysis should be performed by MRI. These studies suggested that DWI/PWI/MRA may be able to identify patients who are most likely to benefit from thrombolytics, and that the PWI>DWI pattern in particular is associated with an improved outcome from thrombolytic therapy. However, many questions remain unanswered and a lot of work is necessary before MRI guided thrombolysis in acute cerebral stroke becomes a part of the standard care.

Calcifications are uncommon in metastases. Adenocarcinoma, osteopenic, osteosarcoma, lung and breast carcinoma can be the origin. A rare case of calcified cystic brain metastasis deriving from papillary cystadenocarcinoma is reported.

Purpose: To prospectively evaluate whether dose reduction and the application of a prebolus technique can effectively alleviate signal saturation effects in T1 dynamic contrast enhanced (T1-DCE) magnetic resonance imaging (MRI) data in breast tumors and lead to increased diagnostic efficacy of the regional tumor blood flow (TBF) values obtained with deconvolution of T1-DCE MRI data. Materials and Methods: After obtaining informed consent, 23 women (32–80 years) with histologically proven breast tumors underwent MR mammography that included a whole-breast T1 DCE sequence. In the slice where the tumor enhanced maximally, a prebolus protocol was applied. One mL of Gd-DTPA solution at 2 mL/s was injected at the beginning of a dynamic axial single slice inversion-prepared turbo field echo acquisition. At the 400th dynamic, a high dose of either 20 mL (15 patients) or 10 mL (8 patients) of contrast agent was injected at 2 mL/s and a further 400 dynamics were acquired. From the aortic prebolus curve an arterial input function (AIF) was reconstructed by time-shifting and adding the prebolus data. The relative enhancement time course from the tumor region of interest was deconvolved with the reconstructed AIF to generate the impulse response function, the maximum of which yielded the TBF. The institutional ethical committee approved the study. Results: Reducing the contrast dose by a factor of 2 led to an increase in diagnostic contrast for the TBF values of malignant and benign tumors by a factor of slightly more than 2. Addition of the prebolus technique improved this further by 45%. receiver operating characteristic analysis showed a significant increase of diagnostic yield related to the combined use of a prebolus and minimal dose. Conclusion: Using a prebolus approach provides an estimate of the unsaturated AIF, while reduction of the high-dose bolus minimizes possible saturation effects in the tumor time course. J. Magn. Reson. Imaging 2010;31:556–561. ©2010 Wiley-Liss, Inc.

Purpose To determine the association between renal cortical perfusion parameters from T1-DCE magnetic resonance imaging (MRI) and age in human kidney. Materials and Methods Thirty-five patients (mean age: 53 years, SD = 15 years) were imaged using inversion recovery (IR)-prepared FLASH (pulse repitition time [TR] = 4.4 msec, echo time [TE] 2.2 msec, inversion time [TI] = 180 msec, FA 50°, matrix 128 × 256, 0.3 sec/slice) during the injection of Gadolinium-DTPA. Tissue concentration–time courses were deconvolved. Renal blood flow (RBF), volume of distribution (RVD), and mean transit time (MTT) were derived from the resulting impulse response function. Results Mean RBF, RVD, and MTT were 127 mL/min/100 mL (SD = 81 mL/min/100 mL), 40 mL/100 mL (SD 23 mL/100 mL), and 22 sec (SD = 9 sec). A significant moderately negative correlation was found between RBF and age (R = −0.447, P = 0.007), RVD and age (R = −0.420, P = 0.012). MTT and age did not show a significant correlation (R = 0.017, P = 0.924). Repeating this analysis for each gender revealed a moderate age dependence of RBF (R = −0.600 with P = 0.009) and RVD (R = −0.540 with P = 0.021) in the male group only. Conclusion T1-DCE quantitative perfusion MRI was sufficiently sensitive to demonstrate a significant negative correlation of RBF and RVD with patient age. This was due to a moderate age dependence of these quantities in males that seems to be absent in females. J. Magn. Reson. Imaging 2009;29:398–403. © 2009 Wiley-Liss, Inc.

Postmastectomy edema is a current complication after axillary lymph node dissection in cases of breast cancer treatment. Staging is important in order to select those patients who can benefit from complex physical therapy (CPT). Different imaging techniques can be used to evaluate the edema. Ultrasonography (US) is a harmless, cheap, and easily applicable technique to visualize the dermal and subcutaneous tissue, but interpretation of the obtained images is not always evident. The aim of this study was to compare ultrasound images of irreversible edema with tissue histology, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Ultrasonographic images of the edematous dermis show an homogeneous hypoechogenic dermal layer that appears on tissue histology to be less compact, due to the excess of fluid in the interstitium separating the collagen fibres and making it more transparent on light microscopy. MRI of the dermis gives a hyperintense signal, indicating the presence of fluid. In the subcutis, increase of the adipose tissue could be observed on US, MRI, and tissue histology. In the case of lymphedema, the area and perimeter of fat cells is significantly (p < 0.05) increased. Hypoechogenic areas near the muscle fascia are registered on US corresponding with epifascial fluid on MRI, and hyperechogenic branches are embedded within the adipose tissue, on tissue histology seen as large fibrotic septa enclosing adipose cells. MRI has a honeycomb picture corresponding with fluid bound to fibrosis.

✓ A case of solitary dorsal intramedullary schwannoma diagnosed by magnetic resonance imaging and treated surgically is reported. The authors review the previously published cases. The possible etiology of the tumor as well as some difficulties encountered in the diagnostic procedure and treatment are discussed.

Purpose/Introduction: An accurate assessment of the Tumor Blood Flow (TBF) can become crucial for breast cancer management. Earlier studies have demonstrated the feasibility of quantifying perfusion parameters in human breast tumors using a deconvolution analysis of DCE-MRI. However, the TBF values were on average higher than the literature PET values. Earlier in myocardium, it has been shown that a prebolus method will allow the use of high concentrations of contrast agent for tissue analysis, in combination with a lower concentration bolus to maintain the linearity of AIF signal intensity. The aim of the present study was to evaluate the use of the prebolus technique in a small cohort of breast tumors. Subjects and Methods: In vivo perfusion measurements were performed in 23 women with breast tumors on a 1.5 T scanner. The routine MR mammography protocol was applied first. At the slice where tumor enhances maximally, the prebolus protocol was applied 10 minutes later. 1ml of Gd- DTPA solution at 2ml/s was injected at the beginning of a dynamic axial single slice inversion-prepared (IR prepared) TFE acquisition (800 dynamics with a temporal resolution of 0.3s). At the 400th dynamic, a high dose of either 10ml (8 patients, 5 malignant and 3 benign) or 20ml (15 patients, 11 malignant and 4 benign) of contrast agent was injected at 2ml/s and a further 400 dynamics were acquired. ROIs were placed manually over the aorta and the region within the breast lesion with highest enhancement. From the prebolus curve, AIFs were reconstructed by time-shifting and adding the prebolus response curve until the relevant high dose equivalent was reached. The RE time course from the tumor ROI was then deconvolved to generate the parametric maps. Results: Whether the TBF calculation was performed with or without prebolus AIF estimation, the median TBF was higher in malignant tumors compared to the benign ones (p

Introduction: MR derived Tumor Blood Flow (TBF) has the potential to become a noninvasive angiogenic marker that could also be explored in the context of anti-angiogenic therapies for which in vivo biomarkers are currently lacking [1]. Thus, an accurate assessment of TBF can become crucial in deciding the best management for breast cancer patients. We have recently shown the feasibility of quantifying perfusion parameters in human breast tumors using a deconvolution analysis of second bolus Dynamic Contrast Enhanced MR (DCE MR) data [2,3]. In these studies, after locating the lesion on low temporal resolution first bolus post contrast subtracted images, a second bolus injection of the same dose was administered during a single slice high temporal resolution dynamic inversion-prepared turbo field echo sequence. However, the mean TBF values reported in these studies were higher than the results from PET studies [4]. We believe that the methodology described in these reports establishes only a baseline for further improvements in either acquisition or post processing schemes. Factors presumed to affect the TBF estimation are given in Figure 1. In this work, we explore three different key aspects of acquisition/ post processing strategies to improve the accuracy of TBF assessment namely contrast bolus dose, Flip Angle (FA) and tracer concentration C(t) estimation. Materials & Methods: The slice where the tumor enhanced maximally was identified on the subtracted low temporal resolution whole breast first bolus dynamic data on a 1.5 T scanner (Philips Intera). High temporal resolution (360 ms) DCE MR data were acquired during the passage of a second bolus at that slice position using an inversion-prepared turbo field echo sequence (TR/TE/TI 4.9ms/2.4ms/196ms 128x67 matrix reconstructed at 256x204, FOV 230x183 mm2, slice thickness 6 mm, 600 images). The three key aspects in the acquisition/ post processing strategies that were evaluated were (1) Effect of contrast dose reduction on signal saturation and Signal to Noise Ratio (SNR) [5]. (2) Effect of varying FAs in the context of inflow effects and signal saturation [6]. (3) R1 calibration either with a two point method (two FA, 5° & 50°; local calibration) or with a phantom of known concentration (global calibration). Image post-processing was performed on a personal computer using software written inhouse in IDL [7]. Results: The main results of the optimization studies are: (1) At low FA (12°) there is virtually no first-pass peak in the AIF at higher doses, but, as the dose is reduced, a clear peak appears with signs of saturation even at the lowest second bolus dose (5ml). However inflow fluctuations are minimal. At high FA (50°) on the other hand, in spite of the presence of a first pass peak in the AIF at all concentrations, severe inflow fluctuations obscure the intensity curve.(2) Reduction of the contrast dose from the 20 ml standard injection greatly impairs the SNR in the tumor tissue using both FAs. (3) The two point calibration method yields inaccurate R1 estimation due to adding up of errors in multiple steps of R1 quantification. Global calibration in combination with using the body coil reduces the already compromised SNR and also suffers from B1 inhomogeneity due to the simultaneous presence of the breast coil. Relative enhancement (RE) can be accepted as an alternative if local concentrations stay low. Conclusion: In breast tumors, with the existing second bolus method, simultaneous accomplishment of an unsaturated AIF curve and a tissue curve with adequate SNR are diverging demands. To achieve an accurate TBF quantification within these constraints, use can be made of a prebolus technique [8] in a low FA sequence with RE as the tracer concentration estimate (Figure 1). In the prebolus technique, a low dose prebolus provides data that permit reconstruction of an accurate AIF, while a subsequent high dose bolus allows acceptable tumor SNR (Figure 2). Our preliminary results in a small cohort of breast tumors suggest that TBF values comparable to PET based literature values can be obtained by this approach (data not shown). References [1] Pollitt et al. [2005] Oncol Rep.;13(5):931-6. [2] Makkat al [2007] J Magn Reson Imaging;25(6):1159-67. [3] Makkat et al [2007] ISMRM 15:280. [4] Vaupel et al [2000] Int J Oncol 17 869-79 [5] Makkat et al. [2006] ESMRMB 23 783 [6] Sourbron et al [2005] ESMRMB 22 518 [7] Sourbron et al. [2007] Phys Med Biol ;52:429-447. [8] Kostler et al. [2004] Magn Reson Med.;52:296-299

A 63-year old woman was admitted to our hospital for neurological reevaluation and MR-imaging. She had unsuccessfully tried to commit suicide by methanol ingestion on at least two known occasions earlier in life. After the first attempt in 1985, she presented limited visual impairment, followed by a nearly total blindness after the second non-recent ingestion. Clinical examination revealed bipyramidal dysfunction and major visual impairment. MR-imaging was performed on a 1.5-T system. T1 weighted FFE-images in the transverse plane as well as T2-weighted images in the transverse and coronal plane, Flair and T1-weighted FFE-images post Gadolinium contrast administration were obtained. Diffusion weighted imaging (TR 3919 ms, Ted 95, EPI Factor 77) was performed using spin echo multislice single-shot echo-planar imaging (EPI) sequences and ADC map was calculated.

Purpose/Introduction: Renal MRI has the potential to provide anatomical and functional information [1-3]. The aim of this study was to determine the age dependence of T1-DCE MRI based renal blood flow heterogeneity in normal kidneys and to compare it with the results obtained in some examples of renal pathology. Subjects and Methods: Imaging was performed in 15 subjects without known renal disease and in three pathological cases. Average normal patient age was 50 years (SD 18). The pathological cases included an acute renal failure (ARF) at week 0 and 3, an end stage glomerulonephritis (GN) and a significant left renal artery stenosis (RAS) with mild right RAS. All experiments were approved by the local ethical board. Single slice IR-prepared Flash (TR 4.4 ms/ TE 2.2 ms/ TI 180 ms/ FA 50°/ matrix 128*256/ dynamics 400, temporal resolution 0.3 s/slice) was performed during the injection of 10 ml Gd-DTPA. Perfusion post-processing was performed offline using software written in-house in IDL. Signals were converted to tracer concentrations and deconvolved with an aorta AIF with a optimized deconvolution procedure [4]. Parametric maps of renal blood flow (RBF) were calculated. The parameter renal blood flow heterogeneity H(RBF) was introduced in analogy with the approach in histopathology as the standard deviation of the cortex RBF divided by RBF and calculated in each patient. The age dependence of H(RBF) in the normal group was studied. Results: Figure 1 presents a plot of H(RBF) versus age in the normal group. The data did not allow a significant correlation between these two parameters to be established (Pearson r = 0.3 , p = 0.1). The values of H(RBF) in the pathological cases (as well as the average results in the normal group for comparison) are presented in the figure 2. The bar graph indicates an increased H(RBF) in the glomerulonephritis case and a slightly lowered value in the acute phase of renal failure. No difference with normal values was found for the acute renal failure after recovery and in the patient with RAS. Discussion/Conclusion: While at first glance there does seem to be a tendency for H(RBF) to increase with age, this tendency cannot be established statistically on the basis of the present data. It would, however, be consistent with literature on aging [5] and with findings on heterogeneity of cortical circulation based on semi-quantitative measurements in CT [6]. The sensitivity of the technique to demonstrate altered blood flow heterogeneity in the cases of some significant pathology was shown in the pathological examples. The observed reduction in the case of ARF could be explained by the need to access somnolent glomeruli in kidney failure. At present, there is no obvious explanation for the increase in case of GN. More data are needed to confirm these preliminary findings. References: [1] Hermoye L. (2004) MRM 51: 1017-1025 [4] Sourbron S. (2004) PMB 49: 3307-3324 [2] Schoenberg S. (2003) MRM 49: 288-298 [5] Ueda K. (1974) NRIZ 11:147-156 [3] Dujardin M. (2005) MRM 54: 841-9 [6] Kojima S. (2000) AJH 13:346-352

Purpose: Dynamic Contrast Enhanced MRI is a promising non-invasive method for imaging renal perfusion and function [1-5]. The feasibility of voxel-by-voxel perfusion mapping based on deconvolved T1-DCE renal data has already been shown by our group [5]. This study compares the values of perfusion with this method between three different age groups. Methods: Measurements were performed in the supine position at 1.5 T on 15 humans without known or suspected renal disease. The three different age groups were: 20 to 35 years (group A, 5 patients), 50 to 60 years (group B, 6 patients) and above 70 years (group C, 4 patients). Average age was 28 years (SD 7) , 53 years (SD 3) and 72 years (SD 1) respectively in group A, B and C. All experiments were approved by the local ethical board. The first pass of 10 ml Gd-DTPA, injected by power injector at 2cc/s, was acquired using single slice axial IR-prepared Flash (FA 50 °, TI 172 ms, TR 4.4 ms, TE 2.2 ms, slice thickness of 4 mm, matrix size of 128*256, temporal resolution 0.3s/slice ). Postprocessing was performed offline on a personal computer using software written in-house in IDL for Linux (Research Systems, Boulder, CO). Signals were calibrated by using a test tube containing 2mM Gadolinium in saline solution placed in the FOV during the measurement. Signals were converted to tracer concentratios and an arterial input function (AIF) was selected manually in the aorta. The tissue time courses were deconvolved using standard-form Tikhonov regularization and the L-curve criterion for selection of the regularisation parameter [6]. A simple inflow correction was applied. Parametric maps of renal blood flow (RBF), renal blood volume (RBV) and mean transit time (MTT) were calculated as the maximum of the impulse response function (IRF) , the time integral of the IRF and the ratio RBV/ RBF. Only the vascular part of the data (manual cut of at the start of the plateau following the vascular peak in the tracer time courses) was used for calculation in order to estimate RBV.Whole cortical measures of RBF, RBV and MTT were calculated of whole left and right cortex ROIs, drawn on the RBF images. Results: Parametric images with sufficient contrast to noise were obtained in all patients. Figure 1 illustrates a typical result for the quantitative parametric maps of RBF in a patient from each age group. The average results of RBF, RBV and MTT for the different age groups are given in figure 2. Average RBF was 2.1 ml/min/ml with SD 0.5 ml/min/ml (group A), 1.3 ml/min/ml with SD 0.5 ml/min/ml (group B) and 1.5 ml/min/ml with SD 0.7 ml/min/ml (group C). Average RBV and MTT were 0.3 ml/ml SD 0.1 ml/ml and 9s SD 3s (A), 0.3 ml/ml SD 0.2 ml/ml and 11s SD 2 s (B) and 0.3 ml/ml SD 0.06 ml/ml and 13 s SD 4s (C). Based on non parametric statistics (Mann-Whitney), the difference in RBF of age group A and B (p=0.004) and A and C (p=0.03) is significant, while RBF of group B and C (p=0.7) is not significantly different. When we compare RBV, we found no difference between group A and B (p=0.7), group A and C (p=0.6) and B and C (p=1), respectively. For MTT, the results indicate a significant difference between group A and B (p=0.02) and A and C (p=0.004),respectively and no significant difference between group B and C (p=0.8). Conclusion: RBF values are lower than those found in the literature [2,3,8]. This is presumably due to dispersion and/or remaining inflow effects on the AIF estimate: flow related enhancement causes an overestimation of the arterial input function and therefore an underestimation of the perfusion values [9]. The results in these preliminary data suggest a significant difference between RBF and MTT in young patients compared to patients of >50 years, which seems in agreement with physiological considerations since especially in the age group of over 50, more sclerotic glomeruli are found in the healthy population [10]. Although preliminary and highly speculative, study of such physiological mechanisms of pathology with this patient friendly technique seems interesting. References: [1] Hermoye L. et al (2004) MRM 51: 1017- 1025 [2] Schoenberg S. et al (2003) MRM 49:288-298 [3] Aumann S. et al (2003), MRM 49: 276- 287 [4] Pedersen M. et al (2004) Proc. ISMRM 11:879 [5] Dujardin M. et al (2005) MRM 54(4):841-9 [6] Sourbron S. et al (2004) PMB 49:3307-3324 [8] Hierholzer K (1999) Physiologie des Menschen:737-776 [9] Ivancevic M. et al (2003) Proc. ISMRM 11:149 [10]Kaplan C. et al (1975) Am J. Pathol 80(2): 227-34

Background: Myxopapillary ependymoma commonly affects the filum terminale. They are usually well-circumscribed lesions; making complete removal is possible in most cases. Subarachnoidal seeding has been reported months or years after partial or subtotal resection, and more rarely infratentorial metastases. We report an exceptional case presenting with diffuse metastases along the spinal and intracranial subarachnoidal space from the sacral level up to the lateral sulci. Methods: This 25-year-old Caucasian male presented with a 2.5-month history of severe back pain when lying and dysesthesia in both legs. Neurological examination showed only some fasciculations in both quadriceps muscles and was further normal. MR imaging revealed numerous enhancing nodular lesions, varying from 1 to 3 cm in size, scattered throughout the whole spinal cord, around the brainstem and in the Sylvian sulci.We performed a dorsal laminectomy at D4 level because of severe spinal cord compression. Pathological examination demonstrated a myxopapillary ependymoma. Oral chemotherapy was started to avoid radiotherapy regarding the important tumour extent. Despite stable MR imaging, the patient complained of increased back pain and bilateral leg dysesthesia after 2 cycles of Temozolamide and was subsequently treated by radiation therapy. Discussion: Myxopillary ependymoma is considered to be a benign tumour (WHO grade I) arising from the medullar conus and filum terminale involving the whole CNS. The tumour tends to grow slowly, without infiltration of the surrounding neural tissue with seldom metastasis. Intracranial seeding has been reported several months or years after subtotal or partial removal, but spontaneously intracranial seeding at diagnosis is extremely rare.

Estimates of the incidence of arm swelling after axillary lymph node dissection for breast cancer range from 10 to 37%. Yet the subjective sensation of edema is described in at least 54% of patients. The purpose of this research was to examine the structural changes occurring in the subcutaneous tissue that might explain these subjective complaints using multiple imaging modalities. Two female cadavers with unilateral breast amputation and axillary dissection were studied. The dermal and subcutaneous layers of both arms were visualized with high frequency ultrasonography, and magnetic resonance imaging and spectroscopy (MRS), and tissue biopsies were taken for histological evaluation. On the operated side, ultrasound imaging showed a hyperechogenic subcutis and the fat-to-water relationship in adipose cells was higher as measured by MRS. Dissection of the arms revealed structural adipose tissue changes, which were confirmed by microscopic evaluation.

The use of computed tomography (CT) for screening of targeted diseases is gaining much interest in the international medical community. An important aspect in the justification of screening with such a high dose examination is the radiation dose to the patient. The objective of this study was to perform a prospective assessment of the radiation dose and associated risk for deleterious effects from a CT screening programme. The excess lifetime risk of fatal cancer for various screening strategies was quantified by estimating the effective dose and by using age dependent mortality risk factors. The accrued data shows that the excess mortality risk due to screening with CT could be substantial. It ranges from 0.01% up to a few percent, strongly depending on the type and method of screening. Consequently, radiation dose and associate risk should be included as fundamental parameters for outlining and deciding a screening approach with CT. Recent technical developments, such as tube current modulation, are promising tools for dose reduction within the constraint of desired image quality.

no abstract available

Open skull surgery of deeply located intracerebral lesions requires precise determination of the treatment area in 3-dimensional (3-D) space. 3-D MRI can give important additional information in presurgical determination of the surgical approach to the target, taking into account highly functional brain areas and important vascular structures. The day before surgery, a grid composed of 9 tubings intersecting at 90 degrees at 1 cm intervals and filled with a CuSO4 solution is firmly attached to the skin of the patient's head in the presumed region of the craniotomy. A 3-D turbo-FLASH sequence is then performed in the sagittal plane after intravenous Gd-DOTA injection on a 1T Magneton. 3-D surface reconstruction of the cortical gyri and sulci is performed. Once the gyri are identified, the 3-D program is then implemented in order to perform a color display of the cortical veins and of the tumor boundaries. The surgical access is then chosen by the surgeon, taking into account highly functional areas. Finally, the boundaries of the tumor are projected on the cortex reconstruction and on the external reference placed on the skin. The entry place for surgery as well as the size of craniotomy are drawn on the skin and the tubed grid is removed. The accuracy of this method tested in 9 patients with deeply located brain tumors or arteriovenous malformations was very satisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

Purpose: Relative perfusion values measured with DSC-MRI are frequently used in the initial clinical work-up and the follow up of brain tumors [1-3]. However, absolute quantification may not be feasible due to the unknown difference in relaxivity between artery and tissue [4]. In this study, we compare the cerebral blood flow (CBF) values in glioblastoma multiforme, contralateral white as well as grey matter from T1-DCE-based [CBFT1] and T2*-DSC-based [CBFT2*] perfusion, as well as the lesion-to-normal-white matter CBF ratios from both techniques. Methods: All experiments were approved by the local ethical board. 9 measurements were performed in 5 anatomopathologically proven recurrent glioblastma multiforme patients in the supine position at 1.5T using the quadrature head coil (patient 2 to 5 had a baseline and a follow up scan after antiangiogenic therapy; average time between the two scans in the same patient was 29 days). An IR-prepared-FLASH sequence acquiring 3 slices per second (TR 2.4 ms/ TE 2 ms/ TI 190 ms/ FA 50°/ matrix 146*256/ FOV 219-270 mm/ dynamics 250, temporal resolution 0.3s per slice, slice thickness 5 mm) was performed during the injection of 15 ml of a Gd-DTPA solution (Magnevist®) at 2ml/sec. Ten minutes later, a second measurement using T2*-weighted GE EPI perfusion with three slices at the same imaging position as the DCE-based perfusion (12 slices, slice thickness 5 mm, TR 1590ms, TE 52ms, 50 dynamics, temporal resolution 1.43s per 12 slices) was performed with a second bolus of 20 ml Gd-DTPA solution injected at 4ml/sec. Post-processing was performed offline on a personal computer using the software PMI 0.2 written in-house in IDL (Research Systems, Boulder, CO)[5]. Signals were transformed into concentrations by using a test tube containing 2mM Gadolinium in saline solution placed in the FOV during the easurement. Tracer concentrations were deconvolved with an AIF obtained close to the tumor. In each patient the same AIF region was chosen for DCE- and DSC-MRI. A simple inflow correction was applied to the DCE data. Parametric maps of CBF from T1-DCE-based [CBFT1] and T2*-DSC-based perfusion [CBFT2*] were calculated as the maximum of the impulse response function. In each patient similar regions of interest were manually drawn by a radiologist (MD) on the CBFT1 and CBFT2* maps. CBFT1 and CBFT2* values were calculated for tumor, contralateral white and grey matter. These average CBF values were compared, as well as lesion-to-normal CBF ratio for DCE-based (CBFLTN,T1) and DSCbased (CBFLTN,T2*) perfusion. Results: Figure 1 illustrates a parametric map of CBFT1 (top) and CBFT2* (bottom) at the same tumor location. Figure 2 shows a scatter plot of CBFT1 and CBFT2* values for tumor as well as for grey and white matter and a scatter plot of CBFLTN,T1 and CBFLTN,T2*. No significant correlation was found between CBFT1 and CBFT2* in tumor (R= -0.6, p=0.07), in white (R= -0.07, p=0.9) and grey matter (R= -0.5, p=0.2). However, CBFLTN,T1 and CBFLTN,T2* showed a significant correlation (R=0.8, p=0.008). Conclusion: The CBF measures from DSC-based perfusion were systematically higher compared to the CBF from DCEbased perfusion and CBF measures from both techniques did not show any correlation. Overestimation of DSCMRI values was reported earlier [6]. The observation is consistent with the overestimation expected by the difference in relaxivity between artery and tissue [4]. In view of the observed correlations between the relative values, DSC-MRI CBF values may be reliable when normalized to a reference tissue type. However, since values of CBFT1 are more in line with the findings for grey and white matter CBF from PET[7], DCE-based perfusion measures of CBF seem to be preferable in tumor perfusion work-up and follow up. References: [1] Akella et al (2004) JMRI 20 (6): 913-22 [2] Hakyemez et al (2005) Clin Radiol 60(4): 493-502 [3] Hakyemez et al (2006) JMRI 24(4): 817-24 [4] Kiselev (2001) MRM 46: 1113-1122 [5] Sourbron et al (2007) PMB 52:429-447 [6] Smith et al (2000) JMRI 12: 400-410 [7] Grandin et al (2005) Neuroimage 26: 525-535

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Purpose: To prospectively determine whether breast carcinomas possess characteristic values of tumor blood flow (TBF) that correlate with pathologic and molecular prognostic markers. Materials and Methods: The institutional ethics committee approved this study. After informed consent was obtained, 57 women (age range, 31-80 years) with histologically proved breast cancer underwent routine magnetic resonance (MR) mammography, which included a whole-breast dynamic contrast material-enhanced (DCE) sequence. A second contrast material bolus was injected during dynamic single-section turbo field-echo imaging of the section where the lesion was maximally enhanced. The relative signal intensity changes were deconvolved in a pixelwise fashion to yield the TBF. Formalin-fixed paraffin-embedded tumor specimens on slides were evaluated for histologic size and grade, as well as for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) protein. In patients with a HER2 protein score of 2+ or 3+, HER2 gene status was assessed. For all prognostic parameters, the Mann-Whitney U test was used to compare median TBF in the HER2-positive group with that in the HER2-negative group. Results: Significantly higher TBF was observed in tumors larger than 2 cm in diameter and in PR-negative and HER2 gene-amplified tumors (P

BACKGROUND AND PURPOSE: The purposes of this study were to find the role of diffusion-weighted MR imaging in characterizing intracerebral masses and to find a correlation, if any, between the different parameters of diffusion-weighted imaging and histologic analysis of tumors. The usefulness of diffusion-weighted imaging and apparent diffusion coefficient (ADC) maps in tumor delineation was evaluated. Contrast with white matter and ADC values for tumor components with available histology were also evaluated. METHODS: Twenty patients with clinical and routine MR imaging/CT evidence of intracerebral neoplasm were examined with routine MR imaging and echo-planar diffusion-weighted imaging. The routine MR imaging included at least the axial T2-weighted fast spin-echo and axial T1-weighted spin-echo sequences before and after contrast enhancement. The diffusion-weighted imaging included an echo-planar spin-echo sequence with three b values (0, 300, and 1200 s/mm), sensitizing gradient in the z direction, and calculated ADC maps. The visual comparison of routine MR images with diffusion-weighted images for tumor delineation aas performed as was the statistical analysis of quantitative diffusion-weighted imaging parameters with histologic evaluation. RESULTS: For tumors, the diffusion-weighted images and,IDC maps of gliomas mere less useful than the T2-weighted spin-echo and contrast-enhanced T1-weighted spin-echo images in definition of tumor boundaries, Additionally:, in six cases of gliomas, neither T2-weighted spin-echo nor diffusion-weighted images were able to show a boundary between tumor and edema, which was present on contrast-enhanced TI-weighted and/or perfusion echo-planar images. The ADC values of solid gliomas, metastases, and meningioma were in the same range, In two cases of lymphomas, there was a good contrast with white matter, with strongly reduced ADC values, For infection, the highest contrast on diffusion-weighted images and lowest ADC values were observed in association with inflammatory granuloma and abscess, CONCLUSION: Contrary to the findings of previous studies, we found no clear advantage of diffusion-weighted echo-planar imaging in the evaluation of tumor extension. The contrast between gliomas, metastases, meningioma, and white matter was generally lower on diffusion- weighted images and ADC maps compared with conventional MR imaging. Unlike gliomas, the two cases of lymphomas shelved hyperintense signal on diffusion-weighted images whereas the case of cerebral abscess showed the highest contrast on diffusion-weighted images with very low ABC values, Further study is required to find out whether this may be useful in the differentiation of gliomas and metastasis from lymphoma and abscess.

Introduction: In breast tumors, a prebolus first pass perfusion method was recently proposed for improved perfusion quantification. This method enables simultaneous accomplishment of an unsaturated AIF curve with the initial prebolus and a tissue curve with adequate SNR with the subsequent high dose. However, an important concern in the prebolus technique in breast tumors remains the selection of a suitable contrast dose protocol. In this study we investigated the effect of dose reduction in the context of prebolus DCE MRI. Materials & Methods: In vivo perfusion measurements were performed in 23 women with breast tumors on a 1.5 T scanner. The routine MR mammography protocol was applied first. In the slice where the tumor enhanced maximally, 10 minutes later prebolus protocol was applied. 1ml of Gd-DTPA solution at 2ml/s was injected at the beginning of a dynamic axial single slice inversion-prepared (IR prepared) TFE acquisition (800 dynamics at a temporal resolution of 0.3s). At the 400th dynamic, a high dose of either 10ml (8 patients, 5 malignant and 3 benign) or 20ml (15 patients, 11 malignant and 4 benign) of contrast agent was injected at 2ml/s and a further 400 dynamics were acquired. ROIs were placed manually over the central part of the aorta and the breast lesion with highest enhancement. From the prebolus curve, AIFs were reconstructed by time-shifting and adding the prebolus response curve until the relevant high dose equivalent is reached. The RE time course from the tumor ROI was then deconvolved. Finally, parametric values were calculated from the impulse response function. Results: Comparison of the tumor RE curves with 10ml and 20ml in two separate patients with same histopathological diagnosis shows a less noisy time intensity curve with the 20ml bolus. The median values of TBF are presented separately for the malignant and benign tumors for both injection protocols, indicating that the median TBF for both malignant and benign tumors are in a matching range. On the other hand, the 1-10 ml protocol achieves a significant difference in the median TBF between benign and malignant tumors (P

Purpose: Renal MRI has the potential to provide anatomical and functional information [1-5]. The feasibility of voxel-by-voxel perfusion mapping based on deconvolved DCE renal data has already been shown by our group [5], but renal blood flow values with this technique are lower than those found in the literature [6]. Possible causes of perfusion underestimation are dispersion (the magnitude of this error is significant in stroke [7]) and partial volume effects from small arterial input functions (AIFs). This study tries to estimate the influence of dispersion and partial volume effects by comparing the perfusion results in renal transplant data deconvolved with two different arterial input functions. In transplants the smaller lobar artery near to the transplant as well as the larger iliac artery further away can be imaged in an axial slice. Methods: Imaging was performed on 5 renal transplant patients in the supine position at 1.5T. All experiments were approved by the local ethical board. Single slice IR-prepared Flash (TR 4.4 ms/ TE 2.2 ms/ TI 180 ms/ FA 50°/ matrix 128*256/ FOV 450-490 mm/ dynamics 400, temporal resolution 0.3 s) was performed during the injection of 10 ml Gd-DTPA injected by power injector at 2ml/s. Post-processing was performed offline on a personal computer using the software PMI 0.2 written in-house in IDL (Research Systems, Boulder, CO). Signals were calibrated by using a test tube containing 2mM Gadolinium in saline solution placed in the FOV during the measurement. Signals were converted to tracer concentrations and deconvolved with an AIF with an optimized deconvolution procedure [8]. A simple inflow correction was applied. Parametric maps of renal blood flow (RBF), renal volume of distribution (RVD) and mean transit time (MTT) were calculated as the maximum of the impulse response function (IRF), the time integral of the IRF and the ratio RVD/ RBF. The tissue time concentrations were deconvolved twice: once with an AIF (pixel ROI) selected manually in a small lobar artery very near to the transplant (resulting in RBFlob, RVDlob and MTTlob) and once with an AIF drawn as a ROI in the much larger iliac artery further away from the target organ (leading to RBFil, RVDil and MTTil).Whole cortical measures of perfusion were calculated of transplant cortex ROIs, drawn on the RBF images. RBFlob, RVDlob and MTTlob were compared to RBFil, RVDil and MTTil, respectively. Results: The average results of RBF, RVD and MTT for the two AIF selections are given in figure 1. Average RBFlob, RVDlob and MTTlob for the 5 transplants were 4.6 ml/min/ml with SD 1.7 ml/min/ml , 1.3 ml/ml with SD 0.7 ml/ml and 21 s with SD 13 s. Average RBFil, RVDil and MTTil were 2.5 ml/min/ml SD 1.0 ml/min/ml, 1.0 ml/ml SD 0.4 ml/ml and 27 s SD 14 s. RBFlob is higher than RBFil in each transplant. RVDlob is higher than RVDil, with one exception (Pat2) where the difference is small. MTTlob is always shorter than MTTil. Conclusion: RVDlob values are higher than RVDil, which cannot be explained by bolus dispersion but is consistent with AIF underestimations due to partial volume effects in the smaller artery. In MTT partial volume effects play no role, so that the trend in the data (MTTlob

Introduction Recent studies have shown that both angiogenesis and HER-2 gene amplification are independent prognostic factors in primary breast cancer [1]. Upregulation of angiogenesis increases both permeability and the number of microvessels in tumors [2]. Characterization of angiogenesis has been performed mostly by in-vitro immunohistochemical evaluation of angiogenic tumor markers. Non-invasive measurement of blood flow in tumors has potential for assessing changes in angiogenic vasculature because the blood flow in tumors is usually abnormal [3]. Previously we demonstrated that the T1-weighted dynamic contrast enhanced MR (DCE-MR), in which the uptake and washout of contrast in tissues is monitored with time and suitably quantified can assist in the diagnosis of breast tumors and can provide information on vascular permeability and perfusion [4]. The aim of our study was to test whether breast carcinomas possess characteristic values of tumor blood flow that depend on HER-2 gene amplification and hormonal receptor status. Materials and Methods: 57 patients with carcinoma of the breast (age range 3180 years; mean 51 years) who underwent mastectomy or wide excision after MR imaging at our institution were studied by in-vivo perfusion measurements on a 1.5 T scanner (Philips Intera). The routine MR mammography protocol was first applied, which included whole breast DCE MR and high-resolution fat suppressed gradient echo sequence. The slice in which the lesion enhanced maximally was located by visual inspection of the subtracted DCE MR images. A second bolus of 0.1 mmol/kg Gd-DTPA was injected and a dynamic single slice IR prepared FLASH acquisition (400 dynamics with a temporal resolution of 0.3s) was performed at that slice position. In this second bolus sequence, the AIF was selected manually in the aorta and the flow-induced signal fluctuations were removed by filtering of the arterial signal-time courses [5]. The relative enhancement time courses were deconvolved pixel-by-pixel, using standardform Tikhonov regularization and an optimized minimization scheme for the L-curve criterion [6]. Finally, the parametric maps of tumor blood flow (TBF), tumor extracellular volume (TEV) and mean transit time (MTT) were generated from the Impulse Response Function (IRF) [4]. Quantitative values for each patient were derived as an average over a ROI covering the whole lesion. The definitive diagnosis was obtained histologically after excisional biopsy or mastectomy. Formalin-fixed, paraffin-embedded slides were reviewed by senior pathologists to evaluate histological size, lymph node status and histological grade and Nottingham prognostic index. Tumor samples were stained for estrogen receptor (ER), progesterone receptor (PR) and HER-2 protein by immunohistochemistry (IHC). Tumors were considered hormone receptor positive if a nuclear staining was observed in at least 5% of the tumor cells. For the HER-2 protein, the slides were scored as 0, 1+, 2+, or 3+ according to DAKO guidelines. For an HER-2 protein DAKO scoreof 2+ and 3+, HER-2 gene status was assessed by fluorescence in-situ hybridization. For both hormone receptors and HER2 gene status, mean TBF was compared beween positive and negative groups. Results: Mean TBF was lower in patients above 50 years, in tumors less than 2 cm in size, low-grade tumors (0-2) and in lymph node negative cases. TBF showed a statistically significant difference between the PR+ and the PR- groups (p value Conclusion: Our preliminary results show that a pixel wise deconvolution analysis of DCE MR data in malignant breast tumors can provide preoperative information regarding the angiogenic status as assessed by the blood flow. Since accurate preoperative rediction regarding high-risk patients is required for neoadjuvant chemotherapy, this noninvasive MR based assessment of TBF and its pattern can provide prognostic and predictive information The trend of increased blood flow in poor prognostic (HER-2 amplified and hormone receptor negative) tumors support the literature findings [1]. Further validation of perfusion data against the biological markers of malignant breast tumors is needed [3] References [1]Blackwell KL et al. (2004) MRM 52:420-429 [2]Miller JC et al. (2005) J Natl Cancer Inst 97:172-187 [3]Pollitt MJK et al. (2005) Oncology reports 13:931-936 [4]Makkat S (2005) ISMRM 13:743 [5]Makkat S (2006) ISMRM 14:1797 [6]Sourbron S et al. (2004) MRM 52:209-213

The efficacy and the minimally invasive nature of the fully transnasal endoscopic procedure in the treatment of pituitary adenomas and other lesions of the sellar area have been widely reported in the literature. Many authors observed similar results in terms of the correction of hormonal hypersecretion in functioning pituitary adenomas using endoscopic endonasal surgery or the traditional microscopic technique. We report the endocrinologic outcome in 2 series of patients operated on at the same institution for functioning pituitary adenomas using these 2 different techniques.This study includes 2 successive series of 60 consecutive patients presenting with a hormonally active pituitary adenoma operated on by the same surgeon. The surgical results obtained in the most recently operated group using a fully endoscopic endonasal technique were compared with those obtained previously using the traditional microsurgical transsphenoidal procedure. The classification of tumors into 4 grades according to Hardy was based on modern MRI and intraoperative findings.The overall remission rate of hypersecretion was 63% in the endoscopic group compared with 50% in the microsurgical group. The most obvious difference between the 2 groups was observed in noninvasive macroadenomas. In this specific grade of tumors, the remission rate of hypersecretion obtained using endoscopy was 78% compared with 43% using microsurgery. The endocrinologic results achieved for microadenomas were similar in the 2 groups. Postoperative CSF leaks occurred more frequently (6 cases) in the endoscopic group.In our experience, fully endoscopic transsphenoidal surgery for functioning pituitary adenomas leads to a better endocrinologic outcome for noninvasive macroadenomas compared to the traditional microsurgical technique. However, morbidity with the endoscopic technique was higher in terms of the rate of postoperative CSF leaks.