Biomedical subjects

Pia C Sundgren

Publications and source records attributed to Pia C Sundgren.

10 recordsLinked to original sources

PubMed2006

Differentiation of recurrent brain tumor versus radiation injury using diffusion tensor imaging in patients with new contrast-enhancing lesions.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the use of diffusion tensor imaging (DTI) in the evaluation of new contrast-enhancing lesions and perilesional edema in patients previously treated for brain neoplasm in the differentiation of recurrent neoplasm from treatment-related injury. METHODS: Twenty-eight patients with new contrast-enhancing lesions and perilesional edema at the site of previously treated brain neoplasms were retrospectively reviewed. Nine directional echoplanar DTIs with b=1000 s/mm(2) were obtained using a single-shot spin-echo echoplanar imaging. Standardized regions of interest were manually drawn in several regions. Mean apparent diffusion coefficient (ADC), fractional anisotropy (FA) and eigenvalue indices (lambda( parallel) and lambda( perpendicular)) and their ratios relative to the contralateral side were compared in patients with recurrent neoplasm versus patients with radiation injury, as established by histological examination or by clinical course, including long-term imaging studies and magnetic resonance spectroscopy. RESULTS: The ADC values in the contrast-enhancing lesions were significantly higher (P=.01) for the recurrence group (range=1.01 x 10(-3) to 1.66 x 10(-3) mm(2)/s; mean+/-S.D.=1.27+/-0.15) than for the nonrecurrence group (range=0.9 x 10(-3) to 1.31 x 10(-3) mm(2)/s; mean+/-S.D.=1.12+/-0.14). The ADC ratios in the white matter tracts in perilesional edema trended higher (P=.09) in treatment-related injury than in recurrent neoplasm (mean+/-S.D.=1.85+/-0.30 vs. 1.60+/-0.27, respectively). FA ratios were significantly higher in normal-appearing white matter (NAWM) tracts adjacent to the edema in the nonrecurrence group (mean+/-S.D.=0.89+/-0.15) than in those in the recurrence group (mean+/-S.D.=0.74+/-0.14; P=.03). Both eigenvalue indices lambda( parallel) and lambda( perpendicular) were significantly higher in contrast-enhancing lesions in the recurrence group than in those in the nonrecurrence group (P=.02). As well, both eigenvalue indices lambda( parallel) and lambda( perpendicular) were significantly higher in perilesional edema than in normal white matter (P<.01 and P<.001, respectively) in both groups. CONCLUSION: The assessment of diffusion properties, especially ADC values and ADC ratios, in contrast-enhancing lesions, perilesional edema and NAWM adjacent to the edema in the follow-up of new contrast-enhancing lesions at the site of previously treated brain neoplasms may add to the information obtained by other imaging techniques in the differentiation of radiation injury from tumor recurrence.

Adolescent↗

PubMed2006

Physiologic and metabolic magnetic resonance imaging in gliomas.

Magnetic resonance (MR) imaging provides excellent soft tissue differentiation and in vivo assessment of physiologic and metabolic properties of tissue. As new and more aggressive treatment modalities and combined modalities are being investigated for brain tumor treatment, it is becoming more important to accurately define tumor volumes for treatment planning, to determine the most aggressive tumor regions for intensified radiation treatment, to identify early regional response to therapy for reoptimization of treatment, and to detect early indicators of developing normal tissue toxicity. Readily available MR techniques of physiologic and metabolic imaging can currently provide useful information regarding tumor tissue properties including chemical composition, cerebral blood volume, perfusion, vascular permeability, and water mobility. This article will focus on the potential value of MR physiologic and metabolic imaging in the clinical management of malignant gliomas.

Central Nervous System Neoplasms↗

PubMed2006

Diffusion imaging: insight to cell status and cytoarchitecture.

Diffusion MR imaging techniques are based on the molecular mobility of water, which is sensitive to interaction with intracellular elements, macromolecules, cell membranes, the density of cells, and microstructural organization. Disease processes that alter cell-water homeostasis, cell density, and cytoarchitecture affect water mobility and are quantifiable by diffusion MR imaging methodologies. Similarly, therapeutic intervention that alters these properties may be monitored for efficacy via diffusion MR imaging. This article outlines basic technical concepts and applications of diffusion imaging with an emphasis on oncology.

Brain↗

PubMed2006

Value of gadolinium in brain MRI examinations for developmental delay.

The aim of this study was to evaluate the added utility of gadolinium administration in the magnetic resonance imaging evaluation of developmental delay in children less than 2 years of age. A computerized retrospective study identified all brain magnetic resonance imaging examinations using gadolinium performed at our institution from 1995-2002 for children under the age of 2 years. Review of the clinical records and magnetic resonance imaging reports identified 170 brain magnetic resonance imaging examinations that were performed for developmental delay. Magnetic resonance imaging studies with enhancing lesions were reviewed by two staff neuroradiologists and two radiology residents. Contrast administration was rated as essential, helpful, or not helpful for each study. In the 107 patients in whom developmental delay was the primary concern, there were no cases in which the findings would have been missed without gadolinium administration. In the 63 patients in whom developmental delay was a secondary concern, there were several cases (11%) where contrast was helpful but not essential in reaching a radiologic diagnosis. In conclusion, intravenous gadolinium has an extremely low yield in children under the age of 2 where developmental delay is the primary concern. In young children for whom developmental delay is a secondary concern, we advocate the use of gadolinium particularly where tumor or infection is clinically suspected.

Age Factors↗

PubMed2006

Diffusion tensor magnetic resonance imaging.

Molecular diffusion plays an important role in many biologic phenomena. The ability to study diffusion, therefore, is extremely useful in physiology and medicine. MRI offers a non-invasive window to diffusion, particularly water self-diffusion. MRI techniques, which provide diffusion sensitivity or quantitation (diffusion tensor MRI [DTI]), have found widespread application in neuroscience and medicine, including the evaluation of stroke, brain development, tumor imaging, and demyelinating disorders. We discuss the tensor nature of diffusion and provide an overview of how DTI offers unique information on tissue organization, water mobility, and disease states, particularly those of neuro-ophthalmologic interest.

Brain↗

PubMed2005

Brain glutamine by MRS in a patient with urea cycle disorder and coma.

In patients who undergo metabolic decompensation from urea cycle disorders, cerebrospinal fluid glutamine level may be a better marker of cerebral dysfunction than blood ammonia or glutamine levels. However, obtaining cerebrospinal fluid by lumbar puncture carries risk in these acutely ill patients with cerebral edema. Using magnetic resonance single voxel spectroscopy as an alternative to cerebrospinal fluid analysis, elevated brain glutamine/glutamate complex levels were detected in a patient with carbamyl phosphate synthetase deficiency, who had been comatose for many days after normalization of blood ammonia and improvement in blood glutamine levels. Brain glutamine by single voxel spectroscopy decreased toward normal with neurologic recovery. We conclude that brain glutamine may be a better marker than serum ammonia for the management of urea cycle disorders, particularly in patients with prolonged mental status changes.

Adolescent↗

PubMed2005

Magnetic resonance spectroscopy.

Magnetic resonance spectroscopy (MRS) complements magnetic resonance imaging (MRI) as a non-invasive means for the characterization of tissue. While MRI uses the signal from hydrogen protons to form anatomic images, proton MRS uses this information to determine the concentration of brain metabolites such as N-acetyl aspartate (NAA), choline (Cho), creatine (Cr) and lactate in the tissue examined. The most widely used clinical application of MRS has been in the evaluation of central nervous system disorders.MRS has its limitations and is not always specific but, with good technique and in combination with clinical information and conventional MRI, can be very helpful in diagnosing certain entities. For example, a specific pattern of metabolites can be seen in disorders such as Canavan's disease, creatine deficiency, and untreated bacterial brain abscess. MRS may also be helpful in the differentiation of high grade from low grade brain tumors, and perhaps in separating recurrent brain neoplasm from radiation injury.

Aspartic Acid↗

PubMed2005

Differentiation between brain tumor recurrence and radiation injury using MR spectroscopy.

OBJECTIVE: The purpose of our study was to explore the feasibility and utility of 2D chemical shift imaging (CSI) MR spectroscopy in the evaluation of new areas of contrast enhancement at the site of a previously treated brain neoplasm. MATERIALS AND METHODS: Two-dimensional CSI (point-resolved spectroscopy sequence [PRESS]; TR/TE, 1,500/144) was performed in 29 consecutive patients (4-54 years old; mean age, 34 years) who had a new contrast-enhancing lesion in the vicinity of a previously diagnosed and treated brain neoplasm. Clinical and imaging follow-up, and histopathology in 16 patients, were used as indicators of the identity of a lesion. RESULTS: Diagnostic-quality spectra were obtained in 97% of the patients. The Cho/Cr (choline/creatine) and Cho/NAA (choline/N-acetyl aspartate) ratios were significantly higher, and the NAA/Cr ratios significantly lower, in tumor than in radiation injury (all three differences, p < 0.0001). The Cho/Cr and Cho/NAA ratios were significantly higher in radiation injury than in normal-appearing white matter (p < 0.0003 and p < 0.0001, respectively), whereas NAA/Cr ratios were not different (p = 0.075). Mean Cho/Cr ratios were 2.52 for tumor, 1.57 for radiation injury, and 1.14 for normal-appearing white matter. Mean Cho/NAA ratios were 3.48, 1.31, 0.79, and mean NAA/Cr ratios were 0.79, 1.22, and 1.38, respectively. When values greater than 1.8 for either Cho/Cr or Cho/NAA ratios were considered evidence of tumor, 27 of 28 patients could be correctly classified. CONCLUSION: Two-dimensional CSI MR spectroscopy can differentiate tumor from radiation injury in patients with recurrent contrast-enhancing intracranial lesions. In these lesions, the Cho/NAA and Cho/Cr ratios may be the best numeric discriminators.

Adolescent↗

PubMed2005

Diffusion-tensor MR imaging of the brain in human immunodeficiency virus-positive patients.

BACKGROUND AND PURPOSE: There is early evidence that diffusion-tensor imaging (DTI) is useful in demonstrating subtle white matter alterations in different diseases of brain. We hypothesize that DTI in several brain regions in human immunodeficiency virus-positive (HIV+) patients is useful in the early detection of HIV-related brain injury. METHODS: MR imaging and DTI were performed in 60 HIV+ patients and in 30 controls. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC; mm/s(2)) maps were generated and coregistered on T2-weighted images. Regions of interest were placed in the splenium and genu of the callosum, the frontal white matter, and the hippocampus. HIV+ patients were divided into those whose CD4 count were <250 cells/mm(3) or >250 cells/mm(3). According to plasma viral loads, patients were divided into those whose viral loads were <50 copies/mL, 50-100,000 copies/mL, or >100,000 copies/mL. RESULTS: Statistically significant decrease of FA was found in the genu of the corpus callosum in HIV+ patients compared with controls. FA was reduced in the frontal white matter and hippocampi in HIV+ patients compared with controls. Differences, however, were not statistically significant. No statistically significant differences were found between the HIV+ groups for FA of the splenium or between these groups and the controls. ADC values were significantly increased in the genu of HIV+ patients when compared with controls and were also increased in other locations, but without statistical significance. CONCLUSION: As used in this study, DTI was not helpful in identifying patients with early HIV infection.

Adolescent↗

PubMedDate not supplied

High incidence of chest malignancy detected by FDG PET in patients suspected of recurrent squamous cell carcinoma of the upper aerodigestive tract.

OBJECTIVE: To determine the incidence of chest neoplasms detected by FDG PET in patients with previously treated squamous cell head and neck cancer (HNC), being evaluated for possible recurrent disease. METHODS: This is a retrospective review of 41 patients (M = 29, F = 12: average age = 58 years) with previously treated HNC who underwent FDG PET of the neck and chest as part of routine evaluation for locoregional and/or distant recurrence. Thirty-four of 41 patients had advanced stage III or IV HNC. All FDG PET studies were reviewed by dedicated nuclear medicine physicians, including evaluation for abnormal uptake in the chest. The chest FDG findings were correlated with serial chest radiographs or chest CT. The occurrence rate of incidental chest malignancy was determined and based on characteristic imaging findings, biopsy, and/or clinical course. RESULTS: Twelve of 41 patients had abnormal FDG uptake in the lungs and/or mediastinum. Ten of 12 patients were found to have neoplasms that could represent either metastases or a new lung primary. Five of these 10 were unsuspected neoplasms prior to FDG PET. The other 2/12 FDG PET scans in the chest were false positive. There was one false-negative FDG PET, with subsequent PET and CT demonstrating pulmonary metastases. Overall, there was a 27% incidence of chest malignancies in patients with advanced HNC being evaluated for possible recurrence. CONCLUSION: Our study demonstrated a chest malignancy in 1 out of 4 patients with advanced HNC being evaluated for locoregional and/or distant spread. Fifty percent were unsuspected prior to FDG PET. This result suggests that FDG PET of the lungs should be routinely included in the evaluation of high-risk patients.

Adult↗