Gadolinium Contrast Injection Research Articles

Extracardiac applications of MR blood pool contrast agent in children.

Magnetic resonance (MR) angiography has significantly reduced the need for diagnostic conventional angiography and is preferred over CT angiography in children because of its lack of ionizing radiation. The availability of gadofosveset trisodium (the only clinically approved blood pool MR contrast agent) has led to an increase in applications of MR for vascular imaging and an improvement in diagnostic quality of MR angiography. Gadofosveset is a gadolinium-based contrast agent that binds reversibly to albumin, resulting in increased paramagnetic effect and longer intravascular residence. This allows for high-resolution arterial and venous MR angiography, assessment of flow characteristics of vascular malformations, dynamic vascular imaging, and multi-station imaging with a single low-dose gadolinium contrast injection. The purpose of this pictorial essay is to facilitate understanding of the kinetics and safety profile of gadofosveset trisodium, discuss technical aspects of imaging, and illustrate advantages and extracardiac applications in pediatric body imaging.

Neuronavigation using susceptibility-weighted venography: application to deep brain stimulation and comparison with gadolinium contrast.

Careful trajectory planning on preoperative vascular imaging is an essential step in deep brain stimulation (DBS) to minimize risks of hemorrhagic complications and postoperative neurological deficits. This paper compares 2 MRI methods for visualizing cerebral vasculature and planning DBS probe trajectories: a single data set T1-weighted scan with double-dose gadolinium contrast (T1w-Gd) and a multi-data set protocol consisting of a T1-weighted structural, susceptibility-weighted venography, and time-of-flight angiography (T1w-SWI-TOF). Two neurosurgeons who specialize in neuromodulation surgery planned bilateral STN DBS in 18 patients with Parkinson's disease (36 hemispheres) using each protocol separately. Planned trajectories were then evaluated across all vascular data sets (T1w-Gd, SWI, and TOF) to detect possible intersection with blood vessels along the entire path via an objective vesselness measure. The authors' results show that trajectories planned on T1w-SWI-TOF successfully avoided the cerebral vasculature imaged by conventional T1w-Gd and did not suffer from missing vascular information or imprecise data set registration. Furthermore, with appropriate planning and visualization software, trajectory corridors planned on T1w-SWI-TOF intersected significantly less fine vasculature that was not detected on the T1w-Gd (p < 0.01 within 2 mm and p < 0.001 within 4 mm of the track centerline). The proposed T1w-SWI-TOF protocol comes with minimal effects on the imaging and surgical workflow, improves vessel avoidance, and provides a safe cost-effective alternative to injection of gadolinium contrast.

Impairment of Subendocardial Perfusion Reserve and Oxidative Metabolism in Nonischemic Dilated Cardiomyopathy

BackgroundCardiac magnetic resonance (CMR) and [11C]acetate positron emission tomography (PET) were used to assess the hypothesis that patients with nonischemic dilated cardiomyopathy (NIDCM) have decreased subendocardial perfusion reserve and impaired oxidative metabolism, consistent with the concept of “energy starvation” in heart failure (HF). Methods and ResultsCMR myocardial perfusion was evaluated in 13 NIDCM patients and 15 control subjects with coronary risk factors and normal myocardial perfusion. The NIDCM patients underwent [11C]acetate PET. The myocardial perfusion index (MPI) was calculated as the normalized rate of myocardial signal augmentation following gadolinium contrast injection. Hyperemic transmural, subendocardial, and subepicardial MPI were reduced in NIDCM compared with control subjects [0.13 vs 0.18 (P < .001), 0.13 vs 0.17 (P < .001), and 0.13 vs 0.17 (P = .008), respectively]. The subendocardial perfusion reserve was 1.59 ± 0.21 vs 1.86 ± 0.32 for the subepicardium (P = .002), demonstrating reduced perfusion reserve. The myocardial oxidative metabolic rate (kmono) per unit demand (rate-pressure product) was reduced in proportion to perfusion reserve (P = .02) ConclusionsImpaired subendocardial perfusion reserve in NIDCM confirmed results previously attained only in animal models. Impaired perfusion and impaired oxidative metabolism are consistent with subendocardial energy starvation in HF.

Seven‐tesla phase imaging of acute multiple sclerosis lesions: A new window into the inflammatory process

In multiple sclerosis (MS), accurate, in vivo characterization of dynamic inflammatory pathological changes occurring in newly forming lesions could have major implications for understanding disease pathogenesis and mechanisms of tissue destruction. Here, we investigated the potential of ultrahigh-field magnetic resonance imaging (MRI; 7T), particularly phase imaging combined with dynamic contrast enhancement, to provide new insights in acute MS lesions. Sixteen active MS patients were studied at 7T. Noncontrast, high-resolution T2* magnitude and phase scans, T1 scans before/after gadolinium contrast injection, and dynamic contrast-enhanced (DCE) T1 scans were acquired. T2*/phase features and DCE pattern were determined for acute and chronic lesions. When possible, 1-year follow-up 7T MRI was performed. Of 49 contrast-enhancing lesions, 44 could be analyzed. Centrifugal DCE lesions appeared isointense or hypointense on phase images, whereas centripetal DCE lesions showed thin, hypointense phase rims that clearly colocalized with the initial site of contrast enhancement. This pattern generally disappeared once enhancement resolved. Conversely, in 43 chronic lesions also selected for the presence of hypointense phase rims, the findings were stable over time, and the rims were typically thicker and darker. These considerations suggest different underlying pathological processes in the 2 lesion types. Ultrahigh-field MRI and, especially, phase contrast, are highly sensitive to tissue changes in acute MS lesions, which differ from the patterns seen in chronic lesions. In acute lesions, the hypointense phase rim reflects the expanding inflammatory edge and may directly correspond to inflammatory byproducts and sequelae of blood-brain barrier opening.

Multiple sclerosis presenting initially with a worsening of migraine symptoms

Multiple sclerosis (MS) is a chronic autoimmune disease that targets myelinated axons in the central nervous system. Headache has been reported as a subtle symptom of the onset of MS, with a variable frequency of 1.6–28.5%; however, it remains unclear whether headache is a true symptom of MS onset. Here, we report the case of a female patient who had a history of migraine without aura and experienced worsening of migraine-headache symptoms as the initial manifestation of MS. Three similar cases were reported previously; however, unlike this case, those cases had no history of migraine without aura. In our case, we excluded factors that could trigger migraine attacks, such as changes in weather, drugs, alcohol, caffeine withdrawal, stress, fatigue, lack of sleep, hormonal therapy, diet, and hunger. The patient had one episode of MS attack with the simultaneous presence of asymptomatic gadolinium-enhancing and non-enhancing lesions, including hyperintense lesions in the bilateral periventricular white matter, body of the corpus callosum, and periaqueductal grey matter, as observed on the T2-weighted images obtained at the first brain magnetic resonance imaging. In addition, after the injection of gadolinium contrast, ring enhancement over these lesions was noted in T1-weighted images, which was suggestive of active demyelination. MS was diagnosed according to the McDonald criteria (2010 revision). We conclude that MS with periaqueductal grey matter involvement may present with worsening migraine. It is important to be cautious if any secondary causes exist, especially when the patient has a history of migraine without aura. MS should be one of the differential diagnoses in young women showing a change in headache pattern or poor clinical drug response to migraine treatment accompanied by episodes of focal neurological deficit. Failure to recognize MS may lead to inappropriate treatment and worse prognosis; early diagnosis in patients with MS is essential to improve their clinical outcomes and quality of life.

039 PREVALENCE AND EXTENT OF INFARCT AND MICROVASCULAR OBSTRUCTION FOLLOWING A RANGE OF REPERFUSION TECHNIQUES IN ST-ELEVATION MYOCARDIAL INFARCTION (STEMI): Table 1

Introduction Cardiac MRI (CMR) provides unique characterisation of myocardial injury post acute STEMI. It is the gold standard for non-invasive measurement of Infarct Size (IS) and tissue perfusion during STEMI. Microvascular obstruction (MVO) describes suboptimal tissue perfusion despite restoration of flow in the infarct-related artery (IRA). IS and MVO are independent predictors of adverse remodelling and prognosis post STEMI. MVO is generally assumed to be related primarily to reperfusion. CMR extent of IS and MVO decreases after 48 h post STEMI. There is a dearth of data on the prevalence and extent of MVO in clinical practice using different reperfusion methods, in particular in those without reperfusion. We hypothesise that the extent and presence of MVO are primarily related to the extent of ischaemic injury rather than reperfusion injury. Method 94 acute STEMI subjects were studied. 75 were prospectively recruited into a study of ventricular remodelling post STEMI. 19 subjects were routine clinical CMR examinations undertaken in non-reperfused, late-presenting patients (>12 h symptoms) to assess viability. Subjects were assessed on a Siemens Avanto 1.5T system. LV function and volumes were assessed using SSFP. Ten minutes after intravenous injection of gadolinium contrast (0.2 mmol/kg), delayed contrast-enhanced images were acquired using a segmented inversion-recovery gradient-echo sequence. IS was defined as areas of hyperenhancement with signal intensity (SI) >50% of peak SI in the infarct core (Full-Width Half-Maximum technique). MVO was defined as hypointensity within areas of infarct. Independent T Test and Mann-Whitney U Test analyses were used for normally and non-parametrically distributed data respectively. Statistical significance was taken at p Results There was no significant difference in age, sex, prevalence of angina, proportion of STEMI with left anterior descending artery IRA, TIMI score or Rentrop (degree of collateralization) score in early reperfused (PCI or Thrombolysis 2 Analysis showed a trend towards higher prevalence of MVO in non-reperfused STEMI (71.4% vs 55.2%). Late PCI patients (n=6) demonstrated a trend towards higher volumes and greater extent of IS and MVO compared with non-reperfused and rescue PCI (n=8) patients. No differences were seen between rescue PCI and non-reperfused patients. Conclusions The prevalence and extent of myocardial and microvascular injury (IS, MVO) on CMR in non-reperfused STEMI is at least as much as that occurring in those undergoing early reperfusion therapy. This is despite a significantly longer time to CMR in non-reperfused patients, which would be expected to result in a reduction in IS and MVO. MVO is not exclusive to reperfusion and may represent the degree of ischaemic injury. Median (25th–75th quartiles) where non-normally distributed. Total study group (n=94) consists of early reperfused, non-reperfused, late PCI and rescue PCI patients.

AIDS-related primary cardiac lymphoma with right-sided heart failure and high-grade AV block: Insights from magnetic resonance imaging

A 44-year-old patient, with personal history of AIDS, was referred to our emergency unit with tachycardia and moderate signs of right-sided heart failure. The cardiac MRI study showed an impairment of the right ventricular free and inferior wall and the interventricular septum. The mass was characterized by notable heterogeneity with mixed areas of hypo- and hypersignal intensity in SSFP and T2-weighted images with fat saturation. There was global hyperenhancement of the mass after gadolinium contrast injection on T1-weighted images with and without fat saturation. The entire right coronary artery was included into the infiltrative mass. One day after the admission, the patient suddenly presented a paroxysmal third degree atrioventricular block, permanently corrected by an implanted cardiac pacemaker. Endomyocardial biopsy conformed the diagnosis of B-cell lymphoma. The patient died 4months after the diagnosis of acute heart failure with multi-organ dysfunction, after a short period of improvement under chemotherapy. We present this case to highlight the importance to consider that a large, solitary, right atrial mass in conjunction with pericardial effusion in a patient with HIV infection should lead to consider, as soon as possible, the diagnosis of lymphoma. MRI has explained the conduction disorders by showing the septal extension of the mass, and by demonstrating right coronary artery involvement.

Myocardial T1 and T2 mapping at 3T: reference values, influencing factors and implications.

BackgroundMyocardial T1 and T2 mapping using cardiovascular magnetic resonance (CMR) are promising to improve tissue characterization and early disease detection. This study aimed at analyzing the feasibility of T1 and T2 mapping at 3 T and providing reference values.MethodsSixty healthy volunteers (30 males/females, each 20 from 20–39 years, 40–59 years, 60–80 years) underwent left-ventricular T1 and T2 mapping in 3 short-axis slices at 3 T. For T2 mapping, 3 single-shot steady-state free precession (SSFP) images with different T2 preparation times were acquired. For T1 mapping, modified Look-Locker inversion recovery technique with 11 single shot SSFP images was used before and after injection of gadolinium contrast. T1 and T2 relaxation times were quantified for each slice and each myocardial segment.ResultsMean T2 and T1 (pre-/post-contrast) times were: 44.1 ms/1157.1 ms/427.3 ms (base), 45.1 ms/1158.7 ms/411.2 ms (middle), 46.9 ms/1180.6 ms/399.7 ms (apex). T2 and pre-contrast T1 increased from base to apex, post-contrast T1 decreased. Relevant inter-subject variability was apparent (scatter factor 1.08/1.05/1.11 for T2/pre-contrast T1/post-contrast T1). T2 and post-contrast T1 were influenced by heart rate (p < 0.0001, p = 0.0020), pre-contrast T1 by age (p < 0.0001). Inter- and intra-observer agreement of T2 (r = 0.95; r = 0.95) and T1 (r = 0.91; r = 0.93) were high. T2 maps: 97.7% of all segments were diagnostic and 2.3% were excluded (susceptibility artifact). T1 maps (pre-/post-contrast): 91.6%/93.9% were diagnostic, 8.4%/6.1% were excluded (predominantly susceptibility artifact 7.7%/3.2%).ConclusionsMyocardial T2 and T1 reference values for the specific CMR setting are provided. The diagnostic impact of the high inter-subject variability of T2 and T1 relaxation times requires further investigation.

Segment-based myocardial T1 and T2 mapping at 3T: feasibility and normal values

Methods Sixty healthy volunteers (30 males / 30 females, 20 in each age group: 20-39 years, 40-59 years, 60-80 years) underwent T1 and T2 mapping of the left ventricle in 3 short axis slices. For T2 maps, 3 single shot steady state free precession (SSFP) images with different T2 preparation times (0, 24, 55ms) were acquired (TE 1.0 ms, TR 2.4 ms, voxel 1.9 x 1.9x6 mm). For T1 maps, Modified Look-Locker Inversion Recovery (MOLLI) technique with 11 single shot SSFP images was used before and after injection of gadolinium contrast (pre-contrast: TE 1.0 ms, TR 2.6 ms, voxel size 1.4-1.7 x 1.4-1.7 x 6 mm). T1 and T2 relaxation times were quantified for each slice and each myocardial segment.

TEP/TDM au FDG et hibernome : à propos d’un cas

Hibernoma is a rare benign tumour of soft tissue, generally asymptomatic, usually discovered in young adults. It is a form of lipoma that originates from brown adipose tissue. Its diagnosis is based on histology, the main differential diagnoses being lipoma and liposarcoma. Its appearance on FDG PET/CT has being described only in few case reports. We report here the case of a 68-year-old patient with ENT cancer in whom an adipose tumour in the left axilla has been discovered on CT performed for staging. The diagnosis of hibernoma was suggested in the report of FDG PET/CT examination and was consistent with results of other imaging modalities. On MRI, contrast enhancement was observed after gadolinium contrast injection, which was not typical for a lipoma. On PET/CT, the FDG uptake by the adipose tumour was very intense (SUVmax=16), which is characteristic for hibernoma that derives from brown adipose tissue. Imaging was unable to distinguish between hibernoma and liposarcoma. The diagnosis of benign mixed hibernoma-lipoma was ascertained on histopathology after complete resection of the tumour. Elements favouring hibernoma over liposarcoma are present in this observation: high avidity for FDG (SUVmax>10) and a fluctuating intensity of uptake, SUVmax of the tumour increasing from 16 to 48 within 16months in the presented case. A high SUVmax on FDG PET in an adipose tumour on CT seems to be more suggestive of a benign tumour, hibernoma, than of its malignant counterpart, liposarcoma.

118 First pass vasodilator-stress myocardial perfusion CMR in mice on a clinical whole-body 3 Tesla scanner: validation against microspheres

BackgroundAnimal models are important to develop our understanding of the pathophysiology of cardiovascular disease and for the development of new therapies. While coronary autoregulation maintains resting MBF constant over a...

Injection of gadolinium contrast through pediatric central venous catheters: a safety study

Catheter rupture during CT angiography has prompted policies prohibiting the use of electronic injectors with peripherally inserted central venous catheters (PICCs) not only for CT but also for MRI. Consequently, many institutions mandate hand injection for MR angiography, limiting precision of infusion rates and durations of delivery. To determine whether electronic injection of gadolinium-based contrast media through a range of small-caliber, single-lumen PICCs would be safe without risk of catheter rupture over the range of clinical protocols and determine whether programmed flow rates and volumes were realized when using PICCs for contrast delivery. Experiments were performed and recorded using the Medrad Spectris Solaris EP MR Injection System. PICC sizes, contrast media and flow rates were based on common institutional protocols. No catheters were damaged during any experiments. Mean difference between programmed and delivered volume was 0.07 ± 0.10mL for all experiments. Reduced flow rates and prolonged injection durations were observed when the injector's pressure-limiting algorithm was triggered, only in protocols outside the clinical range. PICCs commonly used in children can withstand in vitro power injection of gadolinium-based contrast media at protocols significantly above clinical levels.

Extracellular volume imaging by magnetic resonance imaging provides insights into overt and sub-clinical myocardial pathology

Conventional late gadolinium enhancement (LGE) cardiac magnetic resonance can detect myocardial infarction and some forms of non-ischaemic myocardial fibrosis. However, quantitative imaging of extracellular volume fraction (ECV) may be able to detect subtle abnormalities such as diffuse fibrosis or post-infarct remodelling of remote myocardium. The aims were (1) to measure ECV in myocardial infarction and non-ischaemic myocardial fibrosis, (2) to determine whether ECV varies with age, and (3) to detect sub-clinical abnormalities in 'normal appearing' myocardium remote from regions of infarction. Cardiac magnetic resonance ECV imaging was performed in 126 patients with T1 mapping before and after injection of gadolinium contrast. Conventional LGE images were acquired for the left ventricle. In patients with a prior myocardial infarction, the infarct region had an ECV of 51 ± 8% which did not overlap with the remote 'normal appearing' myocardium that had an ECV of 27 ± 3% (P < 0.001, n = 36). In patients with non-ischaemic cardiomyopathy, the ECV of atypical LGE was 37 ± 6%, whereas the 'normal appearing' myocardium had an ECV of 26 ± 3% (P < 0.001, n = 30). The ECV of 'normal appearing' myocardium increased with age (r = 0.28, P = 0.01, n = 60). The ECV of 'normal appearing' myocardium remote from myocardial infarctions increased as left ventricular ejection fraction decreased (r = -0.50, P = 0.02). Extracellular volume fraction imaging can quantitatively characterize myocardial infarction, atypical diffuse fibrosis, and subtle myocardial abnormalities not clinically apparent on LGE images. Taken within the context of prior literature, these subtle ECV abnormalities are consistent with diffuse fibrosis related to age and changes remote from infarction.

A Case of Anaphylactoid Reaction to Gadolinium Contrast Media and Propranolol Complicated with Acute Respiratory Distress Syndrome (ARDS) - A Case Report -

Anaphylaxis/anaphylactoid reaction is a medical emergency. In rare cases, acute respiratory distress syndrome (ARDS) can complicate this disorder. This is a case report of an anaphylactoid reaction complicated with ARDS that was successfully treated using extracorporeal membrane oxygenation (ECMO). A 52-year-old female patient developed sudden dyspnea immediately after she received gadolinium contrast injection and 80 mg of oral propranolol. She progressed rapidly to a state of shock and her chest radiograph showed pulmonary edema. The shock and pulmonary edema did not respond to epinephrine or steroid injection. On the next day, the permeability edema worsened and laboratory test revealed extreme hemoconcentration. The oxygenation goal was not achieved with mechanical ventilation alone, thus ECMO was applied as well. The patient showed clinical improvements on the 3rd day and was weaned from ECMO on the 4th day. She was completely recovered from shock and respiratory distress by day 5. The patient was discharged from hospital without further complications.

The Role of MR Myelography with Intrathecal Gadolinium in Localization of Spinal CSF Leaks in Patients with Spontaneous Intracranial Hypotension

Localization of spinal CSF leaks in CSF hypovolemia is critical in directing focal therapy. In this retrospective review, our aim was to determine whether GdM was helpful in confirming and localizing spinal CSF leaks in patients in whom no leak was identified on a prior CTM. Forty-one symptomatic patients with clinical suspicion of SIH were referred for GdM after undergoing at least 1 CTM between February 2002 and August 2010. A retrospective review of the imaging and electronic medical records was performed on each patient. In 17 of the 41 patients (41%), GdM was performed for follow-up of a previously documented leak at CTM. In the remaining 24 patients (59%), in whom GdM was performed for a suspected CSF leak, which was not identified on CTM, GdM localized the CSF leak in 5 of 24 patients (21%). In 1 of these 5 patients, GdM detected the site of leak despite negative findings on brain MR imaging, spine MR imaging, and CTM of the entire spine. Sixteen of 17 patients with previously identified leaks underwent interval treatment, and leaks were again identified in 12 of 17 (71%). GdM is a useful technique in the highly select group of patients who have debilitating symptoms of SIH, a high clinical index of suspicion of spinal CSF leak, and no demonstrated leak on conventional CTM. Intrathecal injection of gadolinium contrast remains an off-label use and should be reserved for those patients who fail conventional CTM.

Free-Breathing Radial 3D Fat-Suppressed T1-Weighted Gradient Echo Sequence

: To compare free-breathing radially sampled 3D fat suppressed T1-weighted gradient-echo acquisitions (radial volumetric interpolated breath-hold examination [VIBE]) with breath-hold (BH) and free-breathing conventional (rectilinearly sampled k-space) VIBE acquisitions for postcontrast imaging of the liver. : Eighteen consecutive patients referred for clinically indicated liver magnetic resonance imaging were imaged at 3 T. Three minutes after a single dose of gadolinium contrast injection, free-breathing radial VIBE, BH VIBE, and free-breathing VIBE with 4 averages were acquired in random order with matching sequence parameters. Radial VIBE was acquired with the "stack-of-stars" scheme, which uses conventional sampling in the slice direction and radial sampling in-plane.All image data sets were evaluated independently by 3 radiologists blinded to patient and sequence information. Each reader scored the following parameters: overall image quality, respiratory motion artifact, pulsation artifact, liver edge sharpness, and hepatic vessel clarity using a 5-point scale, with the highest score indicating the most optimum examination. Mixed model analysis of variance was used to compare sequences in terms of each measure of image quality. : When scores were averaged over readers, there was no statistically significant difference between radial VIBE and BH VIBE regarding overall image quality (P = 0.1015), respiratory motion artifact (P = 1.0), and liver edge sharpness (P = 0.2955). Radial VIBE demonstrated significantly lower pulsation artifact (P < 0.0001), but had lower hepatic vessel clarity (P = 0.0176), when compared with BH VIBE. Radial VIBE had significantly higher image quality scores for all parameters when compared with free-breathing VIBE (P < 0.0001). Acquisition time for BH VIBE was 14 seconds and that of free-breathing radial VIBE and conventional VIBE with multiple averages was 56 seconds each. : Radial VIBE can be performed during free breathing for contrast-enhanced imaging of the liver with comparable image quality to BH VIBE. However, further work is necessary to shorten the acquisition time to perform dynamic imaging.

Does heart rate influence CMR image quality of the coronary vessel wall?

Does heart rate influence CMR image quality of the coronary vessel wall?

Arterial imaging in patients with lower extremity ischemia and diabetes mellitus

Precise, comprehensive imaging of the arterial circulation is the cornerstone of successful revascularization of the ischemic extremity in patients with diabetes mellitus. Arterial imaging is challenging in these patients because the disease is often multisegmental with a predilection for the distal tibial and peroneal arteries. Occlusive lesions and the arterial wall itself are often calcified and patients presenting with ischemic complications frequently have underlying renal insufficiency. Intra-arterial digital subtraction angiography (DSA), contrast enhanced magnetic resonance angiography (MRA), and more recently, computerized tomographic angiography (CTA) have been used as imaging modalities in lower extremity ischemia. Each has specific advantages and shortcomings in this patient population, which will be summarized and contrasted in this review. DSA is an invasive technique most often performed from a femoral arterial puncture and requires the injection of arterial contrast, which can occasionally cause allergic reactions. In patients with pre-existing renal insufficiency, contrast infusion can result in worsening renal failure; although usually self-limited, it may occasionally require hemodialysis, especially in patients with diabetes. However, DSA provides the highest degree of spatial resolution and image quality. It is also the only modality in which the diagnosis and treatment of arterial disease can be performed simultaneously. MRA is noninvasive, and when enhanced with gadolinium contrast injection provides arterial images of comparable quality to DSA and in some circumstances may uncover distal arterial targets not visualized on DSA. However, spatial resolution is inferior to DSA and erroneous interpretations due to acquisition artifacts are common. Specialized equipment and imaging techniques are necessary to minimize their occurrence in the distal lower extremity. In addition, due to the risk of inducing nephrogenic systemic fibrosis, gadolinium-enhanced MRA cannot be used in patients with renal insufficiency. CTA is noninvasive and rapidly performed, with better spatial resolution than MRA, but requires the largest volume of contrast infusion, exposes patients to high-doses of radiation, and is subject to interpretive error due to reconstruction artifacts especially in heavily calcified arteries, limiting its usefulness in many patients with diabetes. For patients in whom the planned intervention is a surgical bypass, DSA and MRA will provide high quality images of the lower extremity arterial anatomy. For patients in whom a catheter-based intervention is the likely treatment, a diagnostic DSA immediately followed by a catheter-based treatment in the same procedure is the preferred approach. In patients with pre-existing renal dysfunction, in which gadolinium-enhanced MRA is contraindicated, DSA or CTA can be performed. However, patients should have an infusion of intravenous normal saline solution or sodium bicarbonate before the procedure to reduce the incidence of contrast-induced nephropathy.

Oligodendroglial hamartoma: a potential source of misdiagnosis for oligodendroglioma

Various subtypes of intracerebral hamartomas, associated with seizure disorders, have long been described. We describe a cerebral hamartoma placed in the left frontal lobe, associated with drug-resistant epilepsy, composed exclusively of mature oligodendroglial cells. The patient was a 27-year-old right-handed male presenting with severe epileptic encephalopathy and symptoms of behavior dysfunction (disinhibition, rage attacks) associated with a left frontal lesion. Magnetic resonance imaging revealed a small area iso-hypointense compared to the gray matter in T1-weighted sequences not enhancing after gadolinium contrast injection in the left frontal site. On histology, a cortical lesion composed of large aggregates of oligodendroglial cells, with round central nuclei and clear perinuclear halos, was observed. Neither mitotic figures nor necrosis were present. Reactivity for Ki67 and P53 was not found. The lesion was well demarcated from the adjacent brain parenchyma and perineuronal satellitosis was not observed in the cortex. In conclusion, albeit extremely rare, recognition of oligodendroglial hamartoma and its distinction from other epileptogenic lesions as dysembryoplastic neuroepithelial tumor or above all oligodendroglioma have important therapeutic and prognostic implications.

003 Comparison of Visual Scoring and Quantitative Planimetry Methods for Estimation of Global Infarct Size on Delayed Enhanced Cardiac MRI and Validation with Myocardial Enzymes

Although delayed enhanced CMR has become a reference method for infarct size quantification, there is no ideal method to quantify total infarct size in a routine clinical practice. In a prospective study we compared the performance and post-processing time of a global visual scoring method to standard quantitative planimetry and we compared both methods to the peak values of myocardial biomarkers. This study had local ethics committee approval; all patients gave written informed consent. 136 patients admitted with reperfused AMI to our intensive care unit had a complete CMR study with Gadolinium-contrast injection 4±2 days after admission. A global visual score was defined on a 17-segment model and compared with the quntitative planimetric evaluation of hyperenhancement. The peak values of serum troponin I (TnI) and creatine kinase (CK) release were measured in each patient. The mean percentage of hyperenhanced myocardium determined by the quantitative planimetry method was (21.3 ± 14.1) with a range of 0-68,6%. There was an excellent correlation between quantitative planimetry and visual global scoring for the hyperenhancement extent's measurement (r=0.91; y=1.04x+3,2; SEE=1.2; P<0.001) The Bland-Altman plot showed a good concordance between the two approaches (mean of the differences = –4.04% with a standard deviation of 6.9). Mean post-processing time for quantitative planimetry was significantly longer than visual scoring post-processing time (23.7± 5.7 minutes VS 5.0 ± 1.1 minutes respectively, P<0.001). Correlation between peak CK and quantitative planimetry was r=0.71 (P<0.001) and r=0.75 (P<0.001) with visual global scoring. Correlation between peak troponin I and quantitative planimetry was r= 0.69 (P<0.001) and r= 0.70 (P<0.001) with visual global scoring. A visual approach based on a 17-segment model allows a rapid and accurate assessment of the myocardial global delayed enhancement. This scoring method could be used on a daily practice and useful for the management strategy of post-MI patients.