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Abass Alavi

Publications and source records attributed to Abass Alavi.

At least 91 records · Page 5Linked to original sources
PubMed2004

Visual processing impairments and decrements in regional brain activity in Alzheimer's disease.

The relationships between intermediate visual processes, involving object and space perception, and regional brain activity using positron emission tomography and single photon emission tomography were investigated in 16 patients with Alzheimer's disease. Significant region specific correlations were found between unfamiliar face matching and cerebral activity in the left occipito-temporal region and middle/inferior temporal regions bilaterally. Letter-word identification correlated significantly with brain activity in the angular gyri and occipital association cortices bilaterally, as well as a broad region of activation in the left hemisphere temporal, parietal and occipital lobes. Additionally, a significant correlation was found between ratings of performance of instrumental activities of daily living and brain activity in occipito-temporal and middle/inferior temporal regions. The present study demonstrates that the neuropathological distribution typically seen in Alzheimer's disease corresponds to impairments in specific aspects of intermediate visual perceptual processing, and it is related to the daily living skills of patients with Alzheimer's disease.

Activities of Daily Living↗
PubMed2004

Use of iodine 131I-tositumomab radioimmunotherapy in a patient with Waldenstrom's macroglobulinemia.

Waldenstrom's macroglobulinemia is an indolent B-cell malignancy that is characterized by high levels of IgM paraprotein production and is incurable with standard chemotherapy. Iodine 131I-Tositumomab (iodine-131-labeled murine anti-CD20 monoclonal antibody; Bexxar) is a novel radioimmunotherapeutic agent that has a high response rate in relapsed or chemotherapy refractory, CD20-positive, low grade or transformed B-cell non-Hodgkin's lymphomas. There are no data on the use of radioimmunotherapy in Waldenstrom's macroglobulinemia. We report a patient with Waldenstrom's macroglobulinemia with transformation to a large B-cell lymphoma, who was treated successfully with iodine 131I-tositumomab. The patient had a complete response to the treatment, including disappearance of any detectable IgM paraprotein. This case report demonstrates the potential for radioimmunotherapy in CD20 positive B-cell malignancies.

Aged↗
PubMed2004

FDG-PET findings in patients with suspected encephalitis.

PURPOSE: Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) may be used to establish a diagnosis of encephalitis, yet prior descriptions are mainly limited to small case reports. We explore the role of FDG-PET in the diagnostic evaluation of encephalitis. METHODS: Brain FDG-PET was acquired in a consecutive case series of 10 cases of suspected encephalitis over a 5-year-period. Cases with positive Lyme serology were excluded. Two expert reviewers graded the FDG-PET studies in blinded fashion with respect to the clinical history. Retrospective review of the clinical history and examination, laboratory findings, electroencephalogram (EEG), and magnetic resonance imaging (MRI) studies was performed. A diagnosis of encephalitis was based on a combination of the clinical and diagnostic examination findings in each case. RESULTS: Encephalitis was diagnosed in 6 of 10 cases. FDG-PET hypermetabolism was demonstrated in 5 cases of encephalitis, most frequently involving the medial temporal lobes. Multifocal hypometabolism was noted in at least 2 regions in all 6 cases of encephalitis, with at least 4 regions of hypometabolism noted in 5 of 6 cases. Nonencephalitis cases revealed hypermetabolism in only 1 of 4 cases, ascribed to status epilepticus. Hypometabolism was evident in all nonencephalitis cases. CONCLUSION: Encephalitis frequently manifests as FDG-PET hypermetabolism, but focal hypometabolism can also be observed. Seizure activity must be excluded as a possible cause of hypermetabolism in patients suspected of having encephalitis. Because other conditions that can cause hypometabolism may mimic encephalitis clinically, FDG-PET is more likely to serve as an adjunct to lumbar puncture, EEG, and clinical findings rather than a primary diagnostic tool in the management of patients suspected of having encephalitis.

Adolescent↗
PubMed2004

Spontaneous regression of follicular, mantle cell, and diffuse large B-cell non-Hodgkin's lymphomas detected by FDG-PET imaging.

Spontaneous regression of non-Hodgkin lymphoma (NHL) has been reported in low-grade tumors but is an extremely rare event in intermediate- and high-grade disease. Documentation of spontaneous regression by serial fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging has not been reported in the literature. We present 3 cases of spontaneous regression, 1 each of follicular lymphoma (FL), mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL), which showed spontaneous regression on serial FDG-PET imaging. All patients underwent serial whole-body FDG-PET scans 60 minutes after intravenous injection of 9-11 mCi of this radiotracer. None of them had any chemotherapy, radiotherapy, or surgery after the baseline PET scan. Spontaneous regression of disease in all 3 cases was correlated with conventional imaging and clinical course. All 3 patients had positive FDG-PET results on their baseline scan. There was complete disappearance of FDG uptake on a follow-up PET scan for the patient with follicular lymphoma. These results suggest complete regression. The patients with MCL and DLBCL both showed a significant reduction in FDG uptake on serial whole-body PET scans, suggesting partial regression in both cases. Although spontaneous regression of lymphoma is uncommon, this phenomenon can be successfully demonstrated by FDG-PET imaging. Therefore, serial PET imaging may play an important role in detecting this unusual event and may further enhance our understanding of the biologic behavior of this malignancy.

Aged↗
PubMed2004

Clinical validation of fully 3-D versus 2.5-D RAMLA reconstruction on the Philips-ADAC CPET PET scanner.

INTRODUCTION: Fully three-dimensional (3-D) reconstruction algorithms have the potential to better utilize PET data acquired in true 3-D acquisition modes, as compared to 2-D approaches involving data reduction through rebinning procedures followed by a 2-D or 2.5-D reconstruction. Our previous studies, involving simulated and real phantom data from PET scanners working purely in 3-D acquisition mode, showed that the fully 3-D reconstruction approaches bring appreciable improvement on physical measures and visual image quality as well. Reconstruction procedures utilized in those studies were based upon the row action maximum likelihood algorithm (RAMLA) implemented on our clinical scanners. The purpose of this study was to investigate if the fully 3-D RAMLA reconstruction software brings an appreciable improvement in clinical image quality and reader confidence. MATERIALS AND METHODS: Ninety patient scans acquired on the Philips CPET scanner at our institution were reconstructed using 2.5-D RAMLA and 3-D RAMLA with differing reconstruction parameters. These scans were blindly presented to four experienced PET scan readers who graded various aspects of image quality. RESULTS: Our study concluded that 3-D RAMLA on the CPET scanner reduces artifacts and image noise and improves clinical confidence in interpreting PET images. CONCLUSION: This study led to the routine use of 3-D RAMLA reconstruction on the CPET scanner at our institution.

Algorithms↗
PubMed2004

Catheter-related focal FDG activity on whole body PET imaging.

INTRODUCTION: Whole body FDG positron emission tomography (PET) scan is increasingly being used in the management of a variety of cancers and infections. Cancer patients and other very sick patients have central venous catheters, which could be associated with common complications like thrombosis and infections. We describe catheter-related focal FDG uptake on whole body FDG PET scans in 4 patients. MATERIALS AND METHODS: Four patients underwent whole body FDG-PET scanning 60 minutes after intravenous injection of F18-FDG (2 for localization of site of infection, 1 for primary cancer site localization, and 1 for restaging of colon cancer). The whole body PET images were compared and correlated with the patients' history, radiology and laboratory tests. RESULTS: Focal and intense FDG activity is seen in all 4 patients at the distal end of the intravenous catheter. The average SUV of this activity was 6.3 (n = 3). Catheter-related thrombosis was identified as the cause of FDG activity in 3 patients, whereas catheter-related infection was considered in one patient. CONCLUSION: Focal and intense FDG activity, in relation to the distal end of a central venous catheter, has a benign etiology, usually seen with catheter-related venous thrombosis and can be seen with catheter related infection.

Aged↗
PubMed2004

Iatrogenic artifacts on whole-body F-18 FDG PET imaging.

PURPOSE: Whole-body F-18 FDG PET images frequently show artifacts related to medical and surgical interventions. We present some of the common artifact patterns in this atlas article. MATERIALS AND METHODS: We studied whole-body F-18 FDG PET images of 30 adult patients (17 males and 13 females). Of these, 9 patients had lymphoma, 7 had colon cancer, 6 had lung cancer, 3 had lung nodules, 2 each had breast and bladder cancer, and 1 patient had brain cancer. All patients had a history of some surgical or medical intervention for malignant or some other associated disease. RESULTS: PET images of 8 patients showed artifacts related to implanted prostheses and ports and 9 patients showed artifacts related to percutaneous insertion or opening of catheters, tubes, and stomas. Six patients had artifacts from previous surgery, 3 from previous radiation therapy, 3 from previous chemotherapy, and 1 from changes in glucose metabolism. CONCLUSIONS: Medical and surgical interventions can give rise to artifacts on whole-body F-18 FDG PET images. The possibilities and patterns of these artifacts should be kept in mind while reporting these studies.

Adult↗
PubMed2004

Enhanced marrow [18F]fluorodeoxyglucose uptake related to myeloid hyperplasia in Hodgkin's lymphoma can simulate lymphoma involvement in marrow.

[18F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used for the clinical staging of lymphomas and for assessment of response to therapy. We report the case of a woman with classic Hodgkin's lymphoma who had marked FDG uptake by tumor and bone marrow suggestive of diffuse marrow involvement by lymphoma. However, iliac crest bone marrow examination showed marked myeloid hyperplasia without evidence of lymphoma involvement. We discuss the implications for interpretation of FDG-PET imaging of bone marrow in lymphomas.

Biological Transport↗