Karl Heimberger

Magnetic resonance imaging contrast enhancement of brain tumors at 3 tesla versus 1.5 tesla

Nöbauer-Huhmann IM, Ba-Ssalamah A, Mlynarik V, et al. Magnetic Resonance Imaging Contrast Enhancement of Brain Tumors at 3 Tesla Versus 1.5 Tesla. Invest Radiol 2002;37:114–119. rationale and objectives. To compare the diagnostic efficacy of a standard dose of MRI contrast agent in the evaluation of primary brain tumors and metastases using a high-field 3 tesla MR unit versus a 1.5 tesla MR unit. methods. Sixteen patients with brain tumors were examined at both field strengths using identical axial T1-SE protocols pre- and postcontrast (0.1 mmol/kg gadolinium), and postcontrast coronal 3D GRE with magnetization preparation (MP-RAGE), which was adjusted separately for each field strength. Evaluation of the images was performed quantitatively and, in the case of T1-SE images, also by visual assessment. results. Tumor-to-brain-contrast after gadolinium administration using statistical evaluation of MP-RAGE scans was significantly higher at 3 tesla (97.5) than at 1.5 tesla (46.3). The same was true for T1-SE sequences (93.0 vs. 72.1). Signal enhancement of the lesions in T1-SE sequences was not significantly different between both field strengths. conclusions. Administration of a gadolinium contrast agent produces higher contrast between tumor and normal brain at 3 tesla than at 1.5 tesla.

Effect of contrast dose and field strength in the magnetic resonance detection of brain metastases.

PurposeTo compare the diagnostic efficacy of a standard and cumulative triple dose of magnetic resonance (MR) imaging contrast agent in the evaluation of brain metastases using a high-field 3.0 T MR unit versus a standard field 1.5 T MR unit. MethodsTwenty-two patients with suspected brain metastases were examined at both field strengths using identical postcontrast coronal 3D gradient echo with magnetization preparation, which was adjusted separately for each field strength. In both groups initially, iv injection of 0.1 mmol/kg body weight gadolinium chelate (gadodiamide) and thereafter, 0.2 mmol/kg body weight gadodiamide were administered. Subjective assessment of the images was performed independently by 3 neuroradiologists. Objective measurement of signal-to-noise and contrast-to-noise ratios was obtained. ResultsThe subjective assessment of cumulative triple-dose 3.0 T images obtained the best results compared with other sequences, detecting 84 metastases, followed by 1.5 T cumulative triple-dose enhanced images with 81 brain metastases. The objective assessment confirmed those results, showing significantly higher signal-to-noise and contrast-to-noise ratios with 3.0 T than with 1.5 T. ConclusionsCumulative triple-dose images of both field strengths were superior to standard field strengths. However, administration of gadodiamide contrast agent produces higher contrast between tumor and normal brain on 3.0 T than on 1.5 T, resulting in better detection of brain metastases and leptomeningeal involvement.

Ultrafast magnetic resonance imaging of the brain

The purpose of this study was to compare the diagnostic efficacy of single shot fast spin echo sequence (SSh-FSE), and single shot GRASE-sequence (SSh-GRASE) to the conventional T(2)-weighted fast spin echo-sequence (T(2)-FSE) in the imaging of brain disorders. Thirty three patients with high signal intensity lesions on T(2)-weighted images (n = 28), or intracerebral hemorrhage (n = 5), were examined on a 1.0 T MR scanner, with 23 mT/m gradient strength. The scan time for the conventional T(2)-FSE-sequence was 2 min 57 s, the scan time for the single shot-FSE-, and single shot-GRASE-sequences was 11 sec, and 17 sec, respectively. Twenty-one patients remained still during the examination, whereas 12 could not stay still with consecutive marked motion artifacts. Images were reviewed by three radiologists. Lesion conspicuity, image quality, and artifacts were scored on a subjective scale. Signal-to-noise ratios of lesions and normal tissue and contrast-to-noise ratios (CNR) were measured by region of interest (ROI). In the patient group without motion artifacts conspicuity for lesions > or =5 mm did not show a significant difference on conventional T(2)-FSE, single shot-FSE and single shot-GRASE. Detectability of the smaller lesions was significantly inferior on single shot-FSE-, and single shot-GRASE-sequences in artifact free images. For the patient group with motion artifacts SSh-FSE and SSh-GRASE were markedly superior to the conventional T(2)-FSE. Grey-white differentiation was better on conventional T(2)-FSE. Physiologic ferritin as well as pathologic hemosiderin depositions were slightly darker and therefore better visible on SSh-GRASE than on SSh-FSE. Conventional T(2)-FSE showed significantly more artifacts. In conclusion, SSh-FSE and SSh-GRASE imaging can be used for rapid imaging of the brain in those patients who are claustrophobic or in patients with involuntary movements due to extrapyramidal disorders, as well as in children in whom anesthesia is contraindicated or sedation is not possible.

Extra-CNS metastases of glioblastoma: CT and MR studies.

The case of a 29-year-old man with glioblastoma and multiple metastases outside the CNS is presented. Cervical lymph node involvement was ascertained with CT and magnetic resonance (MR), and numerous bone metastases were detected with skeletal scintigraphy. The extent of the cervical tumor and its relationship to the carotid artery could be better assessed with MR than with CT. The patient died despite repeat operations, radiotherapy, and intraarterial systemic chemotherapy. The importance of radiological screening for detecting glioblastoma metastases in patients with long survival is discussed.

Tension headache and the cervical spine plain X-ray findings

The aim of the present study was to investigate if there is any causal connection between plain X-ray findings of the cervical spine and tension headache. We evaluated the X-rays of the cervical spine of 243 patients, in 91 of which the diagnosis was “tension headache”, in 102 “headache not fulfilling the criteria of tension headache” and in 50 “spondylogenic complaints without headache”. We compared these three groups with regard to frequency and severity of radiologically assessable changes of the cervical spine and found that patients with tension headache had normal findings significantly more often and significantly less often functional or organic changes or both than patients of the other two groups. The radiologically assessable changes of the cervical spine are unlikely to have an essential role in the cause or mechanism of tension headache.