Administration Of Gadopentetate Dimeglumine Research Articles

Assessment of Semiquantitative Parameters of Dynamic Contrast-Enhanced Perfusion MR Imaging in Differentiation of Subtypes of Renal Cell Carcinoma.

SummaryBackgroundTo assess semiquantitative parameters of dynamic contrast-enhanced perfusion MR imaging (DCE) in differentiation of subtypes of renal cell carcinoma (RCC).Material/MethodsProspective study conducted upon 34 patients (27 M, 7 F, aged 25–72 ys: mean 45 ys) with RCC. Abdominal dynamic contrast-enhanced gradient-recalled echo MR sequence after administration of gadopentetate dimeglumine was obtained. The time signal intensity curve (TIC) of the lesion was created with calculation of enhancement ratio (ER), and washout ratio (WR).ResultsThe subtypes of RCC were as follows: clear cell carcinomas (n=23), papillary carcinomas (n=6), and chromophobe carcinomas (n=5). The mean ER of clear cell, papillary and chromophobe RCC were 188±49.7, 35±8.9, and 120±41.6 respectively. The mean WR of clear cell, papillary and chromophobe RCCs were 28.6±6.8, 47.6±5.7 and 42.7±10, respectively. There was a significant difference in ER (P=0.001) and WR (P=0.001) between clear cell RCC and other subtypes of RCC. The threshold values of ER and WR used for differentiating clear cell RCC from other subtypes of RCC were 142 and 38 with areas under the curve of 0.937 and 0.895, respectively.ConclusionsWe concluded that ER and WR are semiquantitative perfusion parameters useful in differentiation of clear cell RCC from chromophobe and papillary RCCs.

"Central vessel sign" on 3T FLAIR* MRI for the differentiation of multiple sclerosis from migraine.

The diagnosis of multiple sclerosis (MS) presently relies on radiographic assessments of imperfect specificity. Recent data using T2* methodology for the detection of the "central vessel sign" (CVS) in MS lesions suggests this novel MRI technique may distinguish MS from other disorders. Our aim was to determine if evaluation for CVS on 3T FLAIR* MRI differentiates MS from migraine. Patients with MS or migraine and a prior brain MRI demonstrating at least two hyperintense lesions ≥3mm were recruited. Exclusion criteria included any additional comorbidity known to cause brain MRI abnormalities. 3T MRI was performed in each participant with administration of gadopentetate dimeglumine, and FLAIR* images were generated in postprocessing. The total number of discrete ovoid lesions ≥3mm were counted on FLAIR, per participant, and subsequently evaluated for presence of CVS on FLAIR*. An exploratory method evaluating for CVS in a maximum of 12 lesions per subject was also completed. Ten participants with MS and 10 with migraine completed the study. The median percentage (quartiles) of lesions in MS participants with CVS was 84 (79, 94) compared to 22 (15, 54) in migraine (P=0.008). In a subanalysis by brain region, in the subcortical and deep white matter, the median percentage (quartiles) of lesions in MS participants with CVS was 88 (81, 100) compared to 19 (11, 54) in migraine (P=0.004). This difference was not identified in juxtacortical, periventricular, or infratentorial regions. Identification of CVS using FLAIR* on 3T MRI helps differentiate MS from migraine, particularly in the subcortical and deep white matter.

Effect of gadolinium on hepatic fat quantification using multi-echo reconstruction technique with T2* correction and estimation.

To determine whether hepatic fat quantification is affected by administration of gadolinium using a multiecho reconstruction technique with T2* correction and estimation. Forty-eight patients underwent the investigational sequence for hepatic fat quantification at 3.0T MRI once before and twice after administration of gadopentetate dimeglumine (0.1mmol/kg). A one-way repeated-measures analysis of variance with pairwise comparisons was conducted to evaluate the systematic bias of fat fraction (FF) and R2* measurements between three acquisitions. Bland-Altman plots were used to assess the agreements between pre- and post-contrast FF measurements in the liver. A P value <0.05 indicated statistically significant difference. FF measurements of liver, spleen and spine revealed no significant systematic bias between the three measurements (P > 0.05 for all). Good agreements (95% confidence interval) of FF measurements were demonstrated between pre-contrast and post-contrast1 (-0.49%, 0.52%) and post-contrast2 (-0.83%, 0.77%). R2* increased in liver and spleen (P = 0.039, P = 0.01) after administration of gadolinium. Although under the impact of an increased R2* in liver and spleen post-contrast, the investigational sequence can still obtain stable fat quantification. Therefore, it could be applied post-contrast to substantially increase the efficiency of MR examination and also provide a backup for the occasional failure of FF measurements pre-contrast. • Fat quantification with IDEAL-based investigational sequence remains stable after gadolinium administration. • It can be integrated into tri-phase liver MRI without adding scan time. • This helps optimize MR protocols and provides more useful information for clinicians.

Imaging Features of Pilocytic Astrocytoma in Cerebral Ventricles.

Our aim was to identify imaging characteristics of pilocytic astrocytomas (PAs) in the cerebral ventricles to help radiologists distinguish PAs from other brain tumors preoperatively. Twelve postsurgery patients with a pathological PA diagnosis were included. Among them, 10 had submitted to surgery based on 3.0-T magnetic resonance imaging sequences and 7 because of computed tomography (CT) results. We analyzed their clinical and radiological records retrospectively. The 12 patients (7 were male) had 13 lesions (11 with a single focus, 1 with multiple foci). Average age was 26.5 years (range, 6-49 years). Clinical symptoms included headache, dizziness, vomiting, and unstable gait. Tumor locations were the lateral ventricle (4), fourth ventricle (7), or both ventricles (1, but multifocal). One tumor had disseminated. PA diameters were 18.7-63.0mm (mean ± standard deviation, 36.5 ± 12.4mm). Nine had a round margin, and four had irregular margins. Two were cystic lesions. Eleven were mixed cystic and solid. CT showed the tumors as low-density masses. Two had calcifications. Their cystic portions showed low signal intensity (SI) on T1-weighted imaging (T1WI) and high SI on T2-weighted imaging (T2WI). The cystic walls and solid portions of the PAs showed slightly low SI on T1WI and slightly high SI on T2WI. After gadopentetate dimeglumine administration, the solid portion showed heterogeneous enhancement, whereas the cystic portion showed no enhancement. Radiological features of intraventricular and extraventricular PAs were similar to typical ones, including enhanced nodules within cysts. Radiological findings can usually diagnose PAs correctly.

Effective performance of contrast enhanced SPACE imaging in clearly depicting the margin of pituitary adenoma.

The aim of this study is to determine if contrast enhanced (CE) sampling perfection with application-optimized contrasts using different flip-angle evolutions (SPACE) images can provide clearer pituitary adenoma margin than conventional CE T1-weighted spin echo (T1-SE) sequence for cavernous sinus (CS) invasion evaluation. 21 healthy volunteers were preformed with SPACE scans before and after administration of gadopentetate dimeglumine at different time points (1, 7 and 13 min). Signal intensity (SI) of regions of interest was plotted in SI/time curves for bilateral CS, pituitary and temporal lobe. 35 patients with pituitary adenoma (≥1 cm) were performed CE T1-SE and CE SPACE scans. Two observers made the visual assessment of the tumor margin delineation and CS invasion evaluation on both SPACE and T1-SE images. Surgical findings were compared with the invasion assessment results. At 1, 7 and 13 min after enhancement, SI of left CS increased 6.7, 9.5 and 11.2% respectively compared with unenhanced images (all p < 0.05). Right CS increased 7.2, 9.3 and 11.3% (all p < 0.05%). Within pituitary, a decline (6.3%, p < 0.05) of SI was measured at 1 min after enhancement. CE SPACE performed superior to those of CE T1-SE sequence in visual assessment of tumor edge (assessment score, 1.66 ± 0.42 vs. 1.23 ± 0.65, p < 0.05), as well as the specificity (86.8 vs. 66.0%, p < 0.05) and accuracy (85.7 vs. 68.6%, p < 0.05) for CS invasion evaluation. CE SPACE could provide better contrast of pituitary adenoma with surrounding CS and clear demonstration of tumor edge for CS invasion evaluation than conventional CE T1-SE sequence.

Cell layers and neuropil: contrast‐enhanced MRI of mouse brain in vivo

Contrast-enhanced T₁- and T₂-weighted MRI at 9.4 T and in-plane resolutions of 25 and 30 µm has been demonstrated to differentiate between neural tissues in mouse brain in vivo, including granule cell layers, principal cell layers, general neuropil, specialized neuropil and white matter. In T₁-weighted MRI of the olfactory bulb, hippocampus and cerebellum, contrast obtained by the intracranial administration of gadopentetate dimeglumine (Gd-DTPA) reflects the extra- and intracellular spaces of gray matter in agreement with histological data. General neuropil areas are highlighted, whereas other tissues present with lower signal intensities. The induced contrast is similar to that in plain T₂-weighted MRI, but offers a 16-30-fold higher contrast-to-noise ratio. Systemic administration of manganese chloride increases the signal-to-noise ratio in T₁-weighted MRI to a significantly greater extent in principal cell layers and specialized neuropil than in granule cell layers, whereas gadolinium-enhanced MRI indicates no larger intracellular spaces in these tissues. Granule cell layers are enhanced no more than general neuropil by manganese, whereas gadolinium-enhanced MRI indicates significantly larger intracellular spaces in the cell layers. These discrepancies suggest that the signal increase after manganese administration reflects cellular activity which is disproportionate to the intracellular space. As a result, principal cell layers and specialized neuropil become highlighted, whereas granule cell layers, general neuropil and white matter present with lower signal intensities.

The effect of gadolinium chelate contrast agent on diffusion-weighted imaging of pancreatic ductal adenocarcinoma

There are only two studies that discuss the effect of a gadolinium chelate contrast agent on pancreatic diffusion-weighted imaging (DWI). However, both studies only included normal pancreas and/or pancreas with pancreatitis and did not include pancreatic ductal adenocarcinoma (PDA). To investigate the effect of gadolinium chelate contrast agent on DWI of PDA. Twenty-two patients (13 men, 9 women; mean age 62 years) with histopathologically proven PDA were included in this study. DWI was acquired before and after administration of gadopentetate dimeglumine (Magnevist) with two b-values: 0 and 1000 s/mm(2). The signal intensity (SI), signal-to-noise ratio (SNR), and the apparent diffusion coefficient (ADC) of the lesion were recorded for comparison. The mean time interval between the initiation of contrast administration and the start of the postcontrast DWI series was 393 s (range, 350-510 s). The SIs and SNRs of lesions of b1000 and b0 images of enhanced images were significantly higher than non-enhanced images (P < 0.001, P < 0.001 for b1000 s/mm(2); P = 0.001, P = 0.001 for b0 s/mm(2)). The ADC of all PDAs revealed no statistically significant difference between non-enhanced and enhanced images (P = 0.709). There was also no significant difference between non-enhanced and enhanced images in subgroups based on grades of differentiation and locations of lesion. With increasing SI and SNR of PDA, intravenous contrast administration does not result in a significant difference in quantitative ADC measurements when comparing precontrast to postcontrast DWI when acquired approximately 6-7 min after administration.

FREE-BREATHING 3D LATE GADOLINIUM ENHANCEMENT CARDIAC MR FOR THE EVALUATION OF LEFT VENTRICULAR INFARCTION IN A SWINE MYOCARDIAL INFARCTION MODEL

ObjectivesThe purpose of this study was to evaluate a new free-breathing 3D phase sensitive inversion-recovery (PSIR) turbo FLASH pulse sequence for the detection of left ventricular myocardial scar in a...

Myelin mapping in the central nervous system of living mice using contrast-enhanced magnetization transfer MRI

This work compares magnetization transfer (MT) MRI of living mice with contrast-enhanced MT MRI using intraventricular administration of gadopentetate dimeglumine (Gd-DTPA), systemic administration of MnCl2, and both. In MT MRI at 9.4 T, the contrast-to-noise ratio (CNR) between white matter (WM) and gray matter (GM) increased by 85% after Gd-DTPA injection into the lateral ventricle. When applied in conjunction with manganese-enhanced MT MRI (117 μm isotropic resolution, 6 min measuring time), Gd-DTPA boosted the CNR increase from +56% to +117%. Additional T1 measurements at 2.35 T revealed that intraventricular Gd-DTPA shortens the T1 of GM much more than that of WM, which corresponds to estimated extracellular spaces of 26% in GM and only 15% in WM. These results explain the additional MT contrast enhancement by Gd-DTPA and demonstrate that the T1 shortening by intracellular Mn2+ is well complemented by extracellular Gd-DTPA. The data suggest a high myelin and low water content to hinder access of hydrophilic paramagnetic agents, so that the resulting differential accumulation effectively reduces the MT saturation in water-rich tissues and thereby facilitates the mapping of myelin-rich tissues. Finally, a 156% CNR increase between GM and WM for contrast-enhanced MT MRI at 9.4T using both Gd-DTPA and manganese allowed for 60μm isotropic resolution (102 min measuring time), which delineated myelinated fibers and layers even within GM areas such as the thalamus and cerebellar cortex. Improved MT contrasts were also seen in the cervical spinal cord.

Gadobutrol for Magnetic Resonance Imaging of Chronic Myocardial Infarction

To compare 0.15 mmol/kg gadobutrol with 0.20 mmol/kg gadopentetate dimeglumine with regard to late gadolinium enhancement (LGE) of infarcted myocardium at magnetic resonance (MR) imaging. Twenty patients with history of chronic myocardial infarction underwent 2 cardiac MR examinations at 1.5 Tesla. For the evaluation of myocardial infarction, late gadolinium enhancement (LGE) imaging was performed with an inversion recovery-prepared gradient-echo sequence 15 minutes after administration of either gadobutrol (r1 = 5.2 mmol(-1)s(-1)) or gadopentetate dimeglumine (r1 = 4.1 mmol(-1)s(-1)). The dose of the contrast agents was adjusted based on the relaxivity of both contrast agents. Hence, gadobutrol and gadopentetate dimeglumine were administered at 0.15 mmol/kg and 0.20 mmol/kg, respectively. Contrast-to-noise ratios (CNR) between infarcted myocardium and remote myocardium (CNR remote) and between infarcted myocardium and left ventricular lumen (CNR lumen) were assessed by 2 independent readers. Additionally, infarct size was assessed semiautomatically by using a threshold of 5 standard deviations above the mean signal intensity of remote myocardium. Subendocardial or transmural LGE was present in 16 of 20 (80%) patients. The optimal inversion time for LGE imaging did not differ significantly between gadobutrol and gadopentetate dimeglumine (275 ± 21 milliseconds [range, 240-320 milliseconds] and 282 ± 23 milliseconds [range, 240-330 milliseconds], respectively; P = 0.32). The CNR remote after administration of gadobutrol (40.0 ± 4.6; 95% confidence interval [CI]: 30.3; 49.7) and gadopentetate dimeglumine (40.6 ± 4.6; 95% CI: 30.9; 50.3) did not show significant differences (P = 0.90), whereas gadobutrol yielded a significantly higher CNR lumen (6.2 ± 3.6; 95% CI: -1.5; 13.9) compared with gadopentetate dimeglumine (0.8 ± 3.6; 95% CI: -6.9; 8.5). Infarct size after administration of gadobutrol (23.7 ± 4.7 mL; 95% CI: 13.6; 33.7) and gadopentetate dimeglumine (23.7 ± 4.7 mL;95% CI: 13.7; 33.8) was not statistically different (P = 0.94). There was an excellent correlation between gadobutrol- and gadopentetate dimeglumine-enhanced assessment of infarct size (Spearman r = 0.99 and r = 0.97 for reader 1 and 2, respectively). This pilot study shows that 0.15 mmol/kg gadobutrol is an effective contrast agent for LGE imaging with better delineation of infarcted myocardium from left ventricular lumen than 0.20 mmol/kg gadopentetate dimeglumine.

MRI Features of Ovarian Fibroma and Fibrothecoma With Histopathologic Correlation

The purpose of this article is to evaluate MRI features of ovarian fibroma and fibrothecoma with histopathologic correlation. In this retrospective study, preoperative MRI examinations of 35 women (mean age, 49 years; range, 24-86 years) with pathologically proven ovarian fibroma (n = 25) or fibrothecoma (n = 10) were reviewed by two radiologists in consensus. MRI features, including visibility of ovaries, presence of capsule, degeneration, T1 and T2 signal, and enhancement pattern, were recorded and correlated with histopathologic features. After administration of gadopentetate dimeglumine, the maximum percentages of enhancement of fibroma or fibrothecoma, myometrium, and, if present, uterine fibroids (11/35 patients) were compared. All fibromas and fibrothecomas appeared well defined, with a mean size of 6.36 × 4.81 cm. Ipsilateral and contralateral ovaries were each seen in 89% (31/35) of patients. Most fibromas and fibrothecomas were isointense to hypointense compared with myometrium on T1-weighted (91% [32/35]) and T2-weighted (77% [27/35]) images. Capsule was noted in 63% (22/35) and degenerative changes were noted in 66% (23/35) of patients. Fibromas and fibrothecomas larger than 6 cm more likely showed capsule (p < 0.0001, Fisher exact probability test), degenerative changes (p = 0.003), peripheral subcapsular cystic areas (p < 0.0001), heterogeneous T2 signal (p = 0.001), and heterogeneous enhancement (p = 0.005). At least four of the above five characteristics were present in 93% (14/15) of fibromas and fibrothecomas larger than 6 cm (p < 0.0001). The maximum percentage of enhancement for fibromas and fibrothecomas (63%) was significantly lower than those for myometrium (131%; p < 0.0001) and fibroids (103%; p < 0.0001), without a statistically significant difference between the maximum percentage enhancement of myometrium and fibroids. A maximum percentage of enhancement less than 75% yielded 92% positive predictive value in differentiating fibromas and fibrothecomas from fibroids. Fibrothecomas had a higher maximum percentage of enhancement than did fibromas (p = 0.01). MRI features of ovarian fibromas and fibrothecomas depend on size, with capsule and degenerative changes common with fibromas and fibrothecomas larger than 6 cm. Fibromas and fibrothecomas enhance less than myometrium and fibroids do, and less than 75% maximum percentage enhancement can help in differentiating fibromas and fibrothecomas from fibroids.

Solitary necrotic nodule of the liver: MR findings in 33 pathologically proved lesions

To determine characteristic magnetic resonance (MR) imaging features of solitary necrotic nodule of the liver. MR images features of thirty-two patients (17 men, 15 women; mean age, 43 years; range, 24-76 years) with pathologically proved solitary necrotic nodule of the liver were retrospectively analyzed for number, size, signal intensity features and enhancement patterns. A total of 33 lesions were identified. The mean diameter was 2.3cm (range 1.0-4.5cm). Thirty lesions (90.9%) were 1.0-3.0cm in diameter and only 3 lesions (9.1%) were larger than 3.0cm. On T1-weighted images, solitary necrotic nodule of the liver appeared hypointense in 31 lesions (93.9%) and isointense in 2 lesions (6.1%). On T2-weighted images, 12 (36.4%) lesions were hyperintense, 15 (45.4%) were isointense or invisible and 6 (18.2%) were hypointense. After injection of gadopentetate dimeglumine, all lesions were hypointense and none of them showed enhancement. Solitary necrotic nodule of the liver is usually small with the size not exceed 3.0cm in diameter. Absence of enhancement on all dynamic phase after gadopentetate dimeglumine administration may be most characteristic feature of solitary necrotic nodule of the liver on MR images, which may help discriminate this entity from metastatic liver tumors and intrahepatic cholangiocarcinoma.

Irreversible Electroporation in the Liver: Contrast-enhanced Inversion-Recovery MR Imaging Approaches to Differentiate Reversibly Electroporated Penumbra from Irreversibly Electroporated Ablation Zones

To evaluate the use of contrast material-enhanced magnetic resonance (MR) imaging with conventional T1-weighted gradient-recalled echo (GRE) and inversion-recovery (IR)-prepared GRE methods to quantitatively measure the size of irreversible electroporation (IRE) ablation zones in the liver in a rat model. All studies were approved by the institutional animal care and use committee and were performed in accordance with institutional guidelines. Seventeen adult male Sprague-Dawley rats were divided into four groups. Rats in groups 1-3 (n = 15 total) underwent IRE performed by using different IRE parameters after gadopentetate dimeglumine administration. Rats in group 4 (n = 2) underwent IRE ablation without prior gadopentetate dimeglumine injection to serve as control animals. MR imaging measurements (with conventional T1-weighted GRE and IR-prepared GRE methods) were performed 2 hours after IRE to predict the IRE ablation zones, which were correlated with pathology-confirmed necrosis areas 24 hours after IRE by using the Spearman correlation coefficient. Bland-Altman plots were also generated to investigate the agreement between MR imaging-measured ablation zones and reference standard histologic measurements of corresponding ablation zones. The necrotic areas measured on the pathology images were well correlated with the hyperintense regions measured on T1-weighted GRE images (r = 0.891, P < .001) and normal tissue-nulled IR images (r = 0.874, P < .001); pathology measurements were also well correlated with the smaller hyperintense regions measured on those IR images with inversion times specifically selected to null signal from the peripheral penumbra surrounding the ablation zone (r = 0.939, P < .001). Bland-Altman plots indicated that these penumbra-nulled IR images provided more accurate predictions of IRE ablation zones, with T1-weighted GRE measurements tending to overestimate ablation zone sizes. Contrast-enhanced MR imaging permits accurate depiction of ablated tissue zones after IRE procedures. IR-prepared contrast-enhanced MR imaging can be used to quantitatively measure IRE ablation zones in the liver. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100645/-/DC1.

E0701 Comparison of free-breathing 3D and conventional 2D late gadolinium enhancement cardiac MR for the evaluation of left ventricular infarction

PurposeTo compare a new free-breathing 3D late gadolinium enhancement (LGE) cardiovascular magnetic resonance with conventional 2D LGE in patients with prior myocardial infarction.MethodsPatients with prior myocardial infarction were studied using...

Imaging Diagnosis of Spinal Intramedullary Tuberculoma: Case Reports and Literature Review

Background/Objective: Spinal intramedullary tuberculoma is rare, accounting for 2/100,000 of cases of tuberculosis and only 2% of all cases of tuberculosis of the central nervous system. Diagnostic imaging is essential to improving diagnosis and management of this disease.Methods: The clinical profile, radiological data, and histological slides of 2 cases of intramedullary tuberculomas confirmed by pathologic examinations were reviewed.Results: In 2 cases, magnetic resonance imaging (MRI) showed thickening of the spinal cord and oval lesions with a low T1-weighted image signal and a typical “target sign” T2-weighted image signal. After gadopentetate dimeglumine administration, the lesion's rim shape was enhanced, showing uneven wall thickness and sharp margins.Conclusions: MRI findings of spinal intramedullary tuberculoma were specific, and accurate diagnosis could be obtained. MRI is the optimal measure because it shows location, size, and number of lesions and the presence of degeneration and necrosis.

Neurotoxic Manifestations of an Overdose Intrathecal Injection of Gadopentetate Dimeglumine

The intravenous administration of gadopentetate dimeglumine (GD) is relatively safe and rarely causes systemic toxicity in the course of routine imaging studies. However, the general safety of intrathecal GD has not been established. We report a very rare case of an overdose intrathecal GD injection presenting with neurotoxic manifestations, including a decreased level of consciousness, global aphasia, rigidity, and visual disturbance.

Three-Dimensional Phase-Sensitive Inversion-Recovery Turbo FLASH Sequence for the Evaluation of Left Ventricular Myocardial Scar

The purpose of this study was to evaluate a new free-breathing 3D phase-sensitive inversion-recovery (PSIR) turbo FLASH pulse sequence for the detection of left ventricular myocardial scar. Patients with suspected myocardial scar were examined on a 1.5-T MR scanner for myocardial late enhancement after the administration of gadopentetate dimeglumine using a segmented 2D PSIR turbo FLASH sequence followed by a navigator-gated 3D PSIR turbo FLASH sequence. Image quality was scored by two independent readers using a 4-point Likert scale (0 = poor, nondiagnostic; 1 = fair, diagnostics may be impaired; 2 = good, some artifacts but not interfering in diagnostics; 3 = excellent, no artifacts). Scars were compared quantitatively in volume and graded qualitatively on the basis of size (area) and location. Thirty-three patients were scanned using both techniques. In 25 patients, the quality of the 3D PSIR images was acceptable. Scars were detected in 12 patients. Hyperenhanced scar volumes (p = 0.43), qualitative analysis of scar area (p = 0.78), and scar location (p = 0.68) were similar for both techniques. More small hyperenhanced scars, corresponding mostly to nonischemic distribution patterns, were detected using 3D PSIR than 2D PSIR. Although 2D and 3D results were found to be highly correlated for scar volume, Bland-Altman analysis indicated a systematic smaller infarct volume on the 2D PSIR scans (R(2) = 0.84). Free-breathing 3D PSIR turbo FLASH imaging is a promising technique for the assessment of left ventricular scar particularly for scar quantification and the detection of small nonischemic scars in the myocardium.

Intestinal Permeability to Glucose after Experimental Traumatic Brain Injury: Effect of Gadopentetate Dimeglumine Administration

Traumatic injuries are the leading cause of mortality in individuals aged 1-44 years, and brain injury significantly contributes to the outcome in nearly one half of all deaths from trauma. At the intestinal level, traumatic brain injury (TBI) induces profound effects, including gastrointestinal mucosa ischaemia and motility dysfunction. However, nothing is known concerning the effect of TBI on the intestinal absorption of glucose. Hence, the aim of this study was to investigate the effect of TBI on the intestinal absorption of glucose by investigating the effect of TBI on the jejunal mucosal-to-serosal apparent permeability (AP-to-BL P(app)) to two glucose model substrates, (3)H-2-deoxy-D-glucose ((3)H-DG) and (3)H-3-O-methyl-D-glucose ((3)H-OMG), and to (14)C-sorbitol. Additionally, we tested if gadopentetate dimeglumine administration could prevent any of the changes observed after TBI. Traumatic brain injury induced an increase in the AP-to-BL P(app) to (3)H-DG. After a 100-min. perfusion of the jejunum, the AP-to-BL P(app) to (3)H-DG in TBI rats was almost 70% higher than in the control rats. There was no change, however, in the AP-to-BL P(app) to neither (3)H-OMG nor (14)C-sorbitol. Interestingly enough, gadopentetate dimeglumine was able to prevent the increase in the AP-to-BL P(app) to (3)H-DG observed after TBI. Given the differences in transport characteristics between (3)H-DG and (3)H-OMG, our results point to the possibility of the Na(+)-independent glucose transporter 2 (GLUT2) being activated by TBI (as the P(app) to (3)H-DG, a GLUT2 substrate, was increased) and the Na(+)-dependent glucose co-transporter (SGLT1) being inhibited by TBI (as the P(app) to (3)H-OMG, a GLUT2 and SGLT1 substrate, remained unchanged). Moreover, gadopentetate dimeglumine prevented these changes associated with TBI.

Effect of gadopentetate dimeglumine administration on intestinal permeability to glucose after traumatic brain injury

We studied the effects of traumatic brain injury (TBI) and gadopentetate dimeglumine (GAD) administration on intestinal glucose absorption. Male Wistar rats were i.p. anaesthetised with ketamine and medetomidine. Thirty minutes after TBI (closed head trauma model) one group of rats (TBIGAD, n = 7) was administered GAD (70 mg.kg−1i.v.) and another group (TBI, n = 7) received saline. Control groups (CONT, n=7) were sham operated and received no weight drop and GAD (n = 7) group was administered GAD. Flat sheets of jejunal tissue in Ussing chambers were used to study mucosal‐to‐serosal permeability (AP‐to‐BL Papp) to two glucose model substrates, 3H‐2‐deoxy‐D‐glucose (3H‐DG) and 3H‐3‐O‐methyl‐D‐glucose (3H‐OMG), and to 14C‐sorbitol. Student's t‐test was used. TBI induced an increase in the AP‐to‐BL Papp to 3H‐DG. After a 100‐min perfusion of the jejunum, the AP‐to‐BL Papp to 3H‐DG in TBI rats was almost 70% higher than in control rats. There was no change in the AP‐to‐BL Papp to neither 3H‐OMG nor 14C‐sorbitol. Interestingly enough, GAD was able to prevent the increase in the AP‐to‐BL Papp to 3H‐DG observed after TBI. Our results suggest that GLUT2 is activated by TBI (as the Papp to DG, a GLUT2 substrate, was increased) and SGLT1 is inhibited by TBI (as the Papp to OMG, a GLUT2 and SGLT1 substrate, remained unchanged). GAD prevented these changes associated with TBI. Acknowledgements: FCT ‐ PTDC/SAU‐FCF/67805/2006

MR Imaging of Prostate after Treatment with High-Intensity Focused Ultrasound

To prospectively evaluate magnetic resonance (MR) imaging findings after high-intensity focused ultrasound (HIFU) treatment of the prostate and to correlate them with clinical and histologic findings. Local ethics committee approval and informed consent were obtained. Fifteen consecutive men aged 46-70 years with organ-confined prostate cancer underwent ultrasonographically guided ablation of the whole prostate. Postoperative MR images were obtained within 1 month (12 patients), at 1-3 months (five patients), and in all patients at 6 months. Prostate volume was measured on T2-weighted images, and enhancing tissue was measured on dynamic images after intravenous administration of gadopentetate dimeglumine. Prostate-specific antigen (PSA) level was measured at regular intervals, and transrectal biopsy was performed in each patient at 6 months after treatment. Initial post-HIFU images showed a central nonenhancing area, surrounded by an enhancing rim. At 6 months, the prostate was small (median volume reduction, 61%) and was of predominantly low signal intensity on T2-weighted images. The volume of prostate enhancing on the initial posttreatment image correlated well with serum PSA level nadir (Spearman r = 0.90, P < .001) and with volume at 6 months (Pearson r = 0.80, P = .001). The three patients with the highest volume of enhancing prostate at the initial posttreatment acquisition had persistent cancer at 6-month biopsy. MR imaging results of the prostate show a consistent sequence of changes after treatment with HIFU and can provide information to the operator about completeness of treatment.