Enhancing Brain Lesions Research Articles

Differentiation of brain metastases by percentagewise quantification of intratumoral-susceptibility-signals at 3 Tesla

IntroductionEvaluation of intratumoral-susceptibility-signals (ITSS) in susceptibility-weighted-imaging (SWI) has been reported to improve diagnostic performance for solitary enhancing brain lesions. Due to the distinct morphologic variability of ITSS, standardized evaluation proved to be difficult. We analyzed, if a new postprocessing method using percentagewise quantification (PQ) of ITSS enables differentiation between different entities of cerebral metastases and may thus improve differential diagnosis in cases of unknown primary. Materials and methodsSWI and contrast enhanced T1-weighted MR images were acquired from 84 patients with intracerebral metastases (20 patients with mamma carcinoma (MC), 15 patients with malignant melanoma (MM), 49 patients with bronchial carcinoma (BC)) at 3Tesla MR. Images were co-registered and enhancing lesions were delineated on T1-weighted images and the outline transferred to the corresponding SWI map. All voxels within the lesion presenting values below a reference value placed in the ventricular system were determined and percentagewise calculated. ResultsDiagnostic performance of percentagewise quantification (PQ) of ITSS, as determined with area under the receiver operating characteristic curve (AUC) was excellent (AUC=0.96; 95% confidence interval (CI) 0.90, 1.00) to discriminate MM from MC, good for the discrimination of MM and BC (AUC=0.81, 95% CI 0.70, 0.92) and poor for the discrimination of MC and BC (AUC=0.60; 95% CI 0.47, 0.73). ConclusionPQ is a new approach for the assessment of SWI that can be used for differential diagnosis of intracerebral metastases. Metastases of MM and MC or BC can be distinguished with high sensitivity and specificity.

Crystal-storing histiocytosis: An unusual relapsing inflammatory CNS disorder

The differential diagnosis of acute leukoencephalopathy often focuses on central nervous system idiopathic inflammatory demyelinating diseases (IIDDs) such as multiple sclerosis (MS). However, a spectrum of conditions mimic IIDDs, therefore it is critical to consider whether symptoms, signs, imaging and/or response to therapies are compatible with the diagnosis. We describe a 32-year-old previously healthy woman presenting with a 2 year history of steroid-responsive relapsing episodes lasting 2–10 days characterized by transient visual blurring, right-hemiparesis, and spells of aphasia. MRI demonstrated multifocal, relapsing, predominantly white matter enhancing brain lesions, a longitudinally extensive cord lesion, and abnormal visual evoked potentials. Notably, some lesions persistently enhanced whereas others demonstrated progressive T2W hypointensity. Brain biopsy revealed an atypical plasma cell infiltrate and crystal-storing histiocytosis, which by mass spectrometry confirmed the presence of macrophages containing intracellular kappa-light chain restricted crystals. Bone marrow was negative. The patient did well for several years on pulse dexamethasone, however subsequent scans demonstrated increasing enhancement. Repeat biopsy demonstrated a clonal plasma cell proliferation. She was treated with melphalan, and has remained stable. Although this patient initially met McDonald criteria, atypical imaging prompted further workup, and advanced proteomic technology helped secured an accurate diagnosis. Crystal-storing histiocytosis should be considered in the differential diagnosis of inflammatory CNS disorders.

Rare Cerebral and Pulmonary Metastases From Low-Grade Basal Cell Adenocarcinoma of the Parotid Gland

Basal cell adenocarcinoma of the parotid gland is a low-grade malignancy that rarely metastasizes. We described a 32-year-old man with history of a right total parotidectomy for basal cell adenocarcinoma of the parotid gland 5 years ago, presenting with severe headache. A brain MRI revealed enhancing brain lesions that were confirmed as metastases from the parotid gland malignancy. A body FDG PET/CT demonstrated 2 mildly hypermetabolic lesions in the lungs, with pathology showing metastatic basal cell adenocarcinoma of the parotid gland.

Modeling MR Imaging Enhancing-Lesion Volumes in Multiple Sclerosis: Application in Clinical Trials

Although the number of enhancing lesions is the typical outcome measure of choice in clinical trials in MS, a potentially more sensitive and statistically more powerful outcome measure is the volume of enhancing lesions. In this study, we assessed the distribution and statistical power of the volume of enhancing brain lesions as an outcome measure by means of their required sample size, and we compared the results with the number of enhancing lesions. First, a literature search was performed to compare the effects of treatment on the number and volume of enhancing lesions. Then, a statistical model was proposed to describe the distribution of the volume of enhancing lesions in 2 datasets of patients with RRMS, and sample sizes for enhancing-lesion volume as primary outcome measure were calculated. A mixture of the binomial and Weibull distribution was determined to model enhancing-lesion volumes in patients. Sample size calculations for enhancing-lesion volumes showed that approximately 94 patients per arm would be required to detect a combination of 20% decrease in lesion volume and 20% increase in patients without enhancing lesions, whereas calculations for enhancing-lesion counts showed that approximately 129 patients would be required to detect a 50% decrease. The mixture of the binomial and Weibull distribution is a suitable approach in modeling new enhancing-lesion volumes in MS and yielded feasible sample size estimates for clinical trials, showing lesion volumes to be an advantageous outcome measure compared with lesion counts in terms of statistical power.

Endogenous endophthalmitis and Horner's syndrome secondary to brain abscess in HIV patient

A 39–year-old Malay gentleman was presented with sudden onset of blurring of vision, associated with pain, redness and partial ptosis in the left eye (LE) for 2 weeks. It was also associated with headache and drowsiness that were progressively worsened. On examination, the vision was hand movement LE. There was partial upper lid ptosis with injected conjunctiva and mild anterior chamber reaction. The view of the posterior segment was hazy on LE. The right eye was essentially normal. On investigation, B-scan ultrasound was suggestive of LE vitreous opacity. CT scan and MRI of the orbit and brain showed multiple enhancing brain lesions. Toxoplasma IgG, anti-HCV and anti-HIV were reactive and the patient was treated with toxoplasma infection.

Clinical Signs, Imaging Features, Neuropathology, and Outcome in Cats and Dogs with Central Nervous System Cryptococcosis from California

Cryptococcus spp. is a fungal pathogen with a predilection for the central nervous system (CNS). To compare the clinical, advanced imaging, and neuropathologic findings in dogs and cats with CNS cryptococcosis, and to evaluate outcome of treatment in these animals. Twenty-six cats and 21 dogs with CNS cryptococcosis. Medical records were reviewed for clinical findings and results of CNS imaging. Archived cerebrospinal fluid and CNS tissue specimens were reviewed for pathology. Findings in cats were compared with those in dogs and the effects of variables on survival were determined by survival curve analysis. When present, pain was localized to the cervical region in dogs and was generalized or localized to the thoracolumbar spine or pelvic limbs in cats. Magnetic resonance imaging (MRI) findings were variable but correlated with CNS histopathological findings of meningitis, meningitis with gelatinous pseudocyst formation, and granulomatous mass lesions. Peripherally enhancing brain lesions were seen only in cats. Histopathologically, the inflammatory response was milder in cats compared with dogs. Remissions of ≥1 year occurred in 32% of treated animals. Altered mentation was associated with negative outcome. Glucocorticoid use after diagnosis was associated with improved survival in the first 10 days. Lesions seen on MRI reflected neuropathological findings and were similar to those reported in human patients. The immune response to infection may differ between cats and dogs, or relate to the infecting cryptococcal species. Long-term (>6 month median survival time) survival may be possible in animals surviving ≥4 days after diagnosis.

Spinal Cord Ring Enhancement in Multiple Sclerosis

To describe the clinical and imaging characteristics of spinal cord ring enhancement in multiple sclerosis (MS). Clinical case series. Academic referral center. Twenty patients with MS who had spinal cord ring enhancement were retrospectively identified from 322 cervical and thoracic spinal cord magnetic resonance imaging studies during a 3-year period. Demographics, disability, and pattern of enhancement on spinal cord and concomitant brain magnetic resonance imaging results. Ring enhancement was seen in 20 patients with spinal cord enhancement, most commonly in the cervical cord. Incomplete or "open" ring enhancement was the dominant pattern in 19 of the 20 patients (95%). Concurrent enhancing brain lesions were present in 14 patients, 8 of which (57%) exhibited a ring pattern of enhancement. At the time of imaging, the Expanded Disability Status Scale scores ranged from 1.0 to 7.0 (median score, 3.0). Ring enhancement is not an uncommon pattern for spinal cord lesions in MS, occurring with a prevalence of 6.2% (20 of 322 imaging studies). The most common pattern is incomplete ring enhancement in the cervical spinal cord. Recognition of this pattern may improve and expedite the diagnosis of MS and preclude the need for invasive diagnostic interventions.

Erlotinib therapy for central nervous system hemangioblastomatosis associated with von Hippel-Lindau disease: a case report

There is a need for effective systemic therapy for central nervous system (CNS) hemangioblastomas (HBs). We report a case of erlotinib therapy for CNS HBs in a patient with von Hippel-Lindau disease, in whom the HBs were associated with diffuse leptomeningeal seeding. We provide the first report of paired serum and cerebrospinal fluid (CSF) levels of erlotinib while on standard dosing. The patient exhibited neurologic and imaging signs of recurrent CNS HBs and progressive leptomeningeal metastasis following surgery, radiation, and stereotactic radiosurgery. The patient was treated with erlotinib 150 mg daily. The patient achieved a minor response to erlotinib therapy, including clinical improvement, reduction in size of two enhancing brain lesions (one of which, however, proved at autopsy to be radiation necrosis) and stabilization of leptomeningeal enhancement. In addition, the CSF white count improved. The duration of response was 9 months. The median plasma and CSF levels of erlotinib while on treatment were 1146.06 and 247.83 ng/ml, respectively (CSF 21.6% of plasma). Erlotinib may have antitumor activity in CNS HBs.

Low-dose contrast-enhanced magnetic resonance imaging of brain metastases at 3.0t using high-relaxivity contrast agents

Lesion-to-brain contrast after gadolinium administration is significantly higher at 3.0 Tesla (T) compared to 1.5 T. The high in vivo relaxivity of gadobenate dimeglumine (Gd-BOPTA) may permit the use of lower-dose contrast agents. To investigate whether low-dose contrast-enhanced MRI at 3.0 T using a high-relaxivity contrast agent (Gd-BOPTA) can achieve a comparable or improved contrast-to-noise ratio (CNR) for the detection of brain metastases compared with examination of the same patient at 1.5 T using a standard dose of gadopentetate dimeglumine (Gd-DTPA). A total of 18 patients with known brain metastases were first imaged at 1.5 T with 0.1 mmol/kg Gd-DTPA. Patients returned at least 24 hours later for imaging at 3.0 T with Gd-BOPTA at cumulative doses of 0.025 mmol/kg, 0.05 mmol/kg, 0.075 mmol/kg, and 0.1 mmol/kg (0.1 mmol/kg body weight overall). The CNR of enhancing brain lesions compared to the normal contralateral white matter was calculated. For the 3.0 T study using different cumulative doses of Gd-BOPTA, the CNR of lesions was compared with CNR of the same lesions imaged at 1.5 T using 0.1 mmol/kg Gd-DTPA, by using the Wilcoxon matched-pairs signed-rank test. At 1.5 T with 0.1 mmol/kg Gd-DTPA, the mean CNR between enhanced lesions and cerebral white matter was 12.01 +/- 2.53. With 3.0 T imaging using different cumulative doses of Gd-BOPTA, the mean CNRs were 7.19 +/- 4.06, 15.31 +/- 6.37, 25.44 +/- 11.02, and 31.88 +/- 13.21. At 3.0 T with 0.05 mmol/kg Gd-BOPTA, CNR was 1.34-fold higher compared to CNR at 1.5 T with 0.1 mmol/kg Gd-DTPA (P <0.01). Comparable contrast enhancement of brain metastases can be achieved with a 0.05-mmol/kg dose of Gd-BOPTA at 3.0 T compared to imaging at 1.5 T using 0.1 mmol/kg Gd-DTPA.

Added Value and Diagnostic Performance of Intratumoral Susceptibility Signals in the Differential Diagnosis of Solitary Enhancing Brain Lesions: Preliminary Study

It has been reported that high-resolution susceptibility-weighted imaging (HR-SWI) is a promising tool for assessing brain tumor characterization noninvasively. The purpose of this study was to determine the added value and diagnostic performance of HR-SWI for differentiating solitary enhancing brain lesions (SELs) by assessing intratumoral susceptibility signals (ITSSs). Sixty-four consecutive patients with SELs, without previous surgery, were retrospectively reviewed. We performed 2 consensus reviews, by using conventional MR images alone and with adjunctive HR-SWI. We applied an ITSS grading system based on the degree of the ITSS. Then, we compared the presence and grade of the ITSSs among specific pathologic types of SELs. Two observers diagnosed tumor pathology accurately in 43 (67%) of 64 SELs after reviewing the conventional images alone and 50 (78%) of 64 SELs after reviewing the adjunctive HR-SWI (P = .016, McNemar test). ITSSs were seen in 25 (100%) of 25 glioblastoma multiformes (GBMs), in 2 (40%) of 5 anaplastic astrocytomas, and in 11 (73%) of 15 metastatic tumors. Although the ITSSs were unable to distinguish between GBMs and solitary metastatic tumors, differentiation between GBMs and solitary metastatic tumors was achieved (P = .01) by using a high ITSS degree (grade 3). Moreover, the ITSSs could discriminate high-grade gliomas from lymphomas and nontumorous lesions with a specificity of 100% (P < .0001). The use of ITSSs on HR-SWIs significantly improves the accuracy for the differential diagnosis of SELs compared with the use of conventional MR imaging alone.

Aspiration biopsy cytomorphology of primary pulmonary germ cell tumor metastatic to the brain

Extragonadal germ cell tumors are uncommon and such tumors originating from the lung parenchyma are extremely rare. This is a case of 68-year-old female who was admitted with complaints of right-sided weakness, inability to maintain her balance, right-sided headache, and bloody sputum. Her workup revealed two enhancing brain lesions and large lung mass involving the left lower lobe. Fine-needle aspiration (FNA) of the lung followed by craniotomy was performed and the patient was initially diagnosed with lung adenocarcinoma metastatic to the brain based on the cytomorphology of the lung FNA and histology of the brain mass. However, retrospective investigation revealed markedly elevated alpha fetoprotein (AFP) of which the cytopathologist was unaware at the time of diagnosis. A review of the cytology and surgical specimen slides, as well as immunohistochemistry (IHC) on the brain tumor and FNA cell block were preformed. On the basis of the slides review, clinical findings, and immunostaining results, a diagnosis of primary pulmonary mixed germ cell tumor, containing choriocarcinoma and yolk sac elements, with brain metastases, was retrospectively made.

Spin-Echo Echo-Planar Perfusion MR Imaging in the Differential Diagnosis of Solitary Enhancing Brain Lesions: Distinguishing Solitary Metastases from Primary Glioma

Unlike the more widely reported gradient-echo echo-planar perfusion-weighted imaging (EPI-PWI) technique, spin-echo (SE) EPI relative cerebral blood volume maps select for blood volume in microvessels <8 microm in diameter. This first report of SE-EPI PWI for distinguishing brain metastasis from high-grade glioma demonstrated 88% sensitivity and 72% specificity in 83 patients. We discuss differences in microvessel architecture between high-grade glioma and brain metastasis that may explain the surprising success of SE-EPI in this application and may deserve further investigation.

CONTRAST‐ENHANCED FLUID‐ATTENUATED INVERSION RECOVERY VS. CONTRAST‐ENHANCED SPIN ECHO T1‐WEIGHTED BRAIN IMAGING

In humans, contrast-enhanced fluid-attenuated inversion recovery (FLAIR) imaging plays an important role in detecting brain disease. The aim of this study was to define the clinical utility of contrast-enhanced FLAIR imaging by comparing the results with those with contrast-enhanced spin echo T1-weighted images (SE T1WI) in animals with different brain disorders. Forty-one dogs and five cats with a clinical suspicion of brain disease and 30 normal animals (25 dogs and five cats) were evaluated using a 0.2 T permanent magnet. Before contrast medium injection, spin echo T1-weighted, SE T1WI, and FLAIR sequences were acquired in three planes. SE T1WI and FLAIR images were also acquired after gadolinium injection. Sensitivity in detecting the number, location, margin, and enhancement pattern and rate were evaluated. No lesions were found in a normal animal. In affected animals, 48 lesions in 34 patients were detected in contrast-enhanced SE T1WI whereas 81 lesions in 44 patients were detected in contrast-enhanced FLAIR images. There was no difference in the characteristics of the margins or enhancement pattern of the detected lesions. The objective enhancement rate, the mean value between lesion-to-white matter ratio and lesion-to-gray matter ratio, although representing an overlap of T1 and T2 effects and not pure contrast medium shortening of T1 relaxation, was better in contrast-enhanced FLAIR images. These results suggest a superiority of contrast-enhanced FLAIR images as compared with contrast-enhanced SE T1WI in detecting enhancing brain lesions.

Multiple ring enhancing brain lesions on computed tomography: An Indian perspective

Background Multiple enhancing computed tomography (CT) brain lesions are common neuroimaging abnormalities in India. Several published case reports suggest that multiple enhancing lesions of the brain can occur with a wide variety of infective and non-infective etiologies. Methods In this prospective follow up study, 110 consecutive patients with two or more than two enhancing brain lesions were subjected to a clinical evaluation and a battery of common investigative tests. Results Infective pathologies were the most common etiology for multiple enhancing lesions of the brain. Tuberculosis was the commonest infective pathology, followed by neurocysticercosis. Neoplastic diseases were common non-infective causes. In majority, brain lesions were metastatic manifestation of a systemic neoplastic disorder. Lung carcinoma was the commonest primary malignancy. One patient each had multiple brain abscesses, Behcet's syndrome and systemic lupus erythematosus. Among 4 human immunodeficiency virus-infected patients, one had toxoplasmosis and two patients were diagnosed to have cryptococcal meningitis. In 45 patients, after initial work up, etiological diagnosis could not be ascertained. These undiagnosed patients were empirically treated with antituberculous drugs and corticosteroids. Six undiagnosed patients showed pulmonary metastasis on repeat X-ray chest. In 10 patients CT lesions completely disappeared. In 5 patients number of CT lesions decreased. Six patients died. However, in majority of the undiagnosed patients follow up CT scans of brain remained unaltered. Conclusion A large number of infectious and non-infectious diseases can cause multiple enhancing lesions of the brain. The work up of these patients should include clinical evaluation, imaging and a battery of laboratory tests. The specific diagnosis may remain a challenge in several cases.

The neuroradiological findings in a case of Revesz syndrome

Revesz syndrome is a variant of dyskeratosis congenita characterized by aplastic anemia, retinopathy, and central nervous system abnormalities. We describe a 3-year-old boy in whom the spectrum of neuroimaging findings, including intracranial calcifications, cerebellar hypoplasia and unusual brain lesions were found by biopsy to be gliosis despite their enhancement and progression. In patients with dyskeratosis-related syndromes, non-neoplastic parenchymal brain lesions occur and gliosis should be considered in the differential diagnosis for progressive enhancing brain lesions. Should this finding be confirmed consistently in additional cases, brain biopsy could potentially be avoided.

Differentiation of recurrent astrocytoma from radiation necrosis: a pilot study with 13N-NH3 PET

Differentiation of posttherapy radiation necrosis from recurrent brain tumor remains a challenging diagnostic problem. The combination of the imaging modalities on the basis of different physiologic mechanisms could improve diagnostic accuracy. The present study assessed the role of (13)N-NH(3) PET in differentiating recurrent cerebral astrocytoma from radiation necrosis. Seven patients, who were previously treated with conventional external-beam radiation therapy after surgical resection for cerebral astrocytomas, and showed the enhancing brain lesions on T1-weighted gadiolinium-enhanced MR studies performed in 6 months or above after the radiotherapies, were examined prospectively with (13)N-NH(3) and FDG PET. Five lesions with tumor recurrence and two with radiation necrosis were histologically verified by either surgical resection or stereotactic biopsy. One lesion of radiation necrosis was confirmed clinicoradiologically. In all eight lesions the (13)N-NH(3) PET scans were concordant with the final diagnosis (100%, 8/8). The lesions with recurrent tumor showed moderately to markedly increased (13)N-NH(3) uptake (grade = 4-5). The lesions with radiation necrosis showed absent or less (13)N-NH(3) uptake than surrounding area (grade = 1-2). The FDG PET scans were concordant with the final diagnosis in six of eight lesions (75%, 6/8), and there were one false-negative result and one false-positive result. The diagnostic result of (13)N-NH(3) PET was discordant with FDG PET in two lesions. One lesion with gliosis and radiation necrosis showed slightly increased FDG uptake (grade = 4), but less (13)N-NH(3) uptake (grade = 2). The other lesion with anaplastic astrocytoma showed moderately increased (13)N-NH(3) uptake (grade = 4), but slightly less FDG uptake than surrounding area (grade = 2). The recurrent astrocytomas showed increased (13)N-NH(3) uptake, and the radiation necrosis showed absent or less (13)N-NH(3) uptake, and (13)N-NH(3) seem superior to (18)F-FDG for this purpose, suggesting that (13)N-NH(3) is a promising tracer for separating radiation necrosis from astrocytoma recurrence. However, the patient population in this study was small. Thus, the further studies are needed to settle this issue.

FDG-PET versus Thallium-201 SPECT in the evaluation of putative CNS lymphoma in AIDS patients

1537 Background: The evaluation of CNS lesions in AIDS patients is challenging as both CNS lymphoma and non-neoplastic lesions can have similar clinical presentations and imaging findings. Both Tl-201 SPECT and FDG PET imaging have been used to differentiate malignancy from infection. This study investigates the accuracy of FDG PET compared to Tl-201 SPECT in the diagnosis of CNS lymphoma in patients with AIDS-associated CNS lesions. Methods: Nine patients with AIDS who were found to have rim enhancing brain lesions on MRI underwent both Tl-201 SPECT and FDG PET imaging prior to diagnosis. Diagnosis was made by stereotactic brain biopsy in 6 pts and clinical follow-up in the remaining 3. FDG PET of the brain was performed using a dedicated PET/CT instrument (GE Discovery) 1 hour after 444 MBq FDG. Brain SPECT was performed on a dual head gamma camera (GE Hawkeye) with 185 MBq Tl-201. Images were reviewed along with MRI for anatomic correlation by 2 experienced nuclear medicine physicians blinded to the diagnosis. Results: 43 MRI lesions in 9 patients were evaluated. Clinically, 5 pts (18 lesions) were diagnosed with lymphoma (4 biopsy proven, 1 with known history of lymphoma), and 4 pts (25 lesions) were diagnosed with toxoplasmosis (2 with negative biopsies for malignancy, 2 with clinical course consistent with toxoplasmosis). FDG PET had true positive results for lymphoma in 5 of 5 pts, while Tl-201 SPECT was true positive in only 2 of 5. FDG PET had true negative results in 4 of 4 pts with toxoplasmosis, while Tl-201 had false positive results in 2 of 4. FDG PET had positive and negative predictive values of 100%, while Tl-201 SPECT had PPV 50% and NPV 40%. On a lesion basis, PET showed increased uptake of FDG in 8 of 18 brain lesions in patients with lymphoma, while SPECT showed increased uptake of Tl-201 in 4 of 18 lesions. Tl-201 was positive in 2 lesions in patients diagnosed with toxoplasmosis, while FDG had no false positive lesions. Conclusion: In this limited study, FDG PET proved to be superior to Tl-201 SPECT in the differentiation of CNS lymphoma from toxoplasmosis (overall accuracy 100% vs 44%, respectively). With the increasing availability of FDG PET, this test should probably supplant Tl-201 SPECT as the study of choice following conventional imaging (CT, MRI) of CNS lesions in AIDS patients. No significant financial relationships to disclose.

Enhancing Lesions of the Brain: Intraindividual Crossover Comparison of Contrast Enhancement After Gadobenate Dimeglumine Versus Established Gadolinium Comparators

Gadobenate dimeglumine (Gd-BOPTA) possesses a two-fold higher T1 relaxivity compared to other available gadolinium contrast agents. The study was conducted to evaluate the benefits of this increased relaxivity for MR imaging of intracranial enhancing brain lesions. Forty-five patients (31 males, 14 females) with suspected glioma or cerebral metastases were evaluated. Patients received Gd-BOPTA and either Gd-DTPA (n = 23) or Gd-DOTA (n = 22) in fully randomized order at 0.1 mmol/kg body weight and at a flow rate of 2 ml/s. The second agent was administered 1-14 days after the first agent. Images were acquired precontrast (T1wSE, T2wFSE sequences) and at sequential postcontrast time-points (T1wSE sequences at 0, 2, 4, 6, and 8 and 15 min and a T1wSE-MT sequence at 12 min) at 1.0 or 1.5 T using a head coil. Determination of contrast enhancement was performed quantitatively (lesion-to-brain ratio, contrast-to-noise ratio, and percent enhancement) and qualitatively (border delineation, internal morphology, contrast enhancement, and diagnostic preference) by two independent, fully blinded readers. Images from 43/45 patients were available for quantitative assessment. After correction for precontrast values, significantly greater lesion-to-brain ratio (P < .003), contrast-to-noise ratio (P < .03), and percent enhancement (P < .0001) was noted by both readers for Gd-BOPTA-enhanced images at all time-points from 2 min postcontrast. Qualitative assessment of all patients similarly revealed significant preference for Gd-BOPTA for lesion border delineation (P < .004), lesion internal morphology (P < .008), contrast enhancement (P < .0001), and diagnostic preference (P < .0005). The greater T1 relaxivity of Gd-BOPTA permits improved visualization of intracranial enhancing lesions compared to conventional gadolinium agents.

Brain Tumors: Full- and Half-Dose Contrast-enhanced MR Imaging at 3.0 T Compared with 1.5 T—Initial Experience

To prospectively and intraindividually compare the effect of magnetic resonance (MR) imaging at a higher magnetic field strength (3.0 T) on contrast-to-noise ratio (CNR) at different doses of a T1-shortening contrast agent in patients with contrast-enhancing brain lesions, with 1.5-T MR imaging as a reference standard. Institutional review board approval and informed consent were obtained for all patient and volunteer studies. Twelve patients (six women, six men; mean age, 58 years; range, 29-76 years) with 12 enhancing brain lesions (11 patients with primary brain tumors and one with a solitary cerebral metastasis) underwent contrast material-enhanced MR imaging three times, on three separate days: once at 1.5 T with a full dose of 0.10 mmol/kg gadopentetate dimeglumine, once at 3.0 T with a full dose, and once at 3.0 T with half that dose, 0.05 mmol/kg. The same contrast-enhanced T1-weighted spin-echo images (repetition time msec/echo time msec, 500/12; section thickness, 5 mm; matrix, 256 x 205) were obtained at both 3.0 T and 1.5 T after prior optimization of parameters at 3.0 T. The number and conspicuity of enhancing brain lesions were assessed with blinded clinical image reading. Signal-to-noise ratio and CNR were determined with region of interest analysis of enhancing lesions and normal contralateral white matter. For 3.0 T with half the standard dose and with the full dose, CNR of lesions was intraindividually compared with CNR at 1.5 T with the full dose by using the Wilcoxon matched-pairs signed rank test. At 3.0 T and full dose, CNR was 2.8-fold higher than that at 1.5 T and full dose (P < .001). At the same time, higher lesion conspicuity at clinical image reading was observed. With only half the standard dose, MR imaging at 3.0 T still yielded higher CNR (1.3-fold higher) than that with full dose at 1.5 T (P < .01). With the same amount of contrast agent, MR imaging at 3.0 T offered a significantly higher CNR of enhancing cerebral lesions, compared with that at 1.5 T; even with the dose reduced by half, CNR was still higher at 3.0 T.

Is inflammation important in early PPMS? a longitudinal MRI study

Background: Magnetic resonance imaging (MRI) studies in primary progressive multiple sclerosis (PPMS) have shown a reduced frequency of enhancement with the contrast agent gadolinium-DTPA (Gd-DTPA), in comparison with relapsing-remitting multiple...