Hyperpolarized helium-3 MR imaging of pulmonary function.
Recent advances in HP MR imaging contrast agents have led to novel tests of pulmonary function. Many of these tests show promise in the clinical arena.
Diffusion↗
Biomedical subjects
Abass Alavi
Publications and source records attributed to Abass Alavi.
Fluorodeoxyglucose-PET in the management of malignant melanoma.
FDG-PET is of limited use in patients with early-stage disease without nodal or distant metastases (stage I-II), because sentinel node biopsy is much more sensitive in detecting microscopic lymph node metastases. Because of the high tumor-to-background ratio, FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. PET has been shown to have a strong role in detecting metastatic disease. FDG-PET is more sensitive than CT for detecting metastatic lesions in skin, lymph nodes, and abdomen, but CT is equivalent to or more sensitive than FDG-PET for detecting small pulmonary lesions. FDG-PET identifies the location and number of metastatic lesions in stage III and IV disease and therefore is important for surgical planning. Most of the false-negative FDG-PET results are caused by micrometastases and lesion smaller than 10 mm. Postsurgical inflammation, other inflammatory lesions, and some benign tumors cause some false-positive FDG-PET results.
Fluorodeoxyglucose F18↗
PET imaging in the assessment of normal and impaired cognitive function.
PET has been used to directly quantify several processes relevant to the status of cerebral health and function, including cerebral blood flow, cerebral blood volume, cerebral rate of oxygen metabolism, and cerebral glucose use. Clinically, the most commonly performed PET studies of the brain are performed with fluorine-18-fluorodeoxyglucose as the imaged radiopharmaceutical. Such scans have demonstrated diagnostic and prognostic use in evaluating patients who have cognitive impairment, and in distinguishing among primary neurodegenerative dementias and other causes of cognitive decline. In certain pathologic circumstances, the normal coupling between blood flow and metabolic needs may be disturbed, and changes in oxygen extraction fraction can have significant prognostic value.
Alzheimer Disease↗
Regression of pulmonary MALT lymphoma after treatment with rituximab.
We describe a patient with extranodal (pulmonary) marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) who was refractory to treatment with cytotoxic chemotherapy. After a single four-week course of rituximab she had significant regression of pulmonary lesions and remains progression free 19 months after finishing her treatment. This case report demonstrates the potential efficacy of rituximab as a single therapeutic agent in patients with pulmonary MALT lymphoma.
Adult↗
Demonstration of excessive metabolic activity of thoracic and abdominal muscles on FDG-PET in patients with chronic obstructive pulmonary disease.
PURPOSE: The purpose of this study was to determine if an FDG-PET study was able to visualize muscle uptake of the chest and abdomen in patients with chronic obstructive pulmonary disease (COPD). METHODS: This study included 25 patients with COPD and 25 patients without COPD who had undergone a FDG-PET study. The nonattenuation-corrected images were used to determine the degree of FDG uptake in the intercostals, subscapular, abdominal rectus, and abdominal oblique muscles. The intensity of uptake in the muscles was rated on a 4-point grading scale with 1 being less, 2 the same, 3 slightly more, and 4 markedly more intense than the sternum. RESULTS: Thirteen patients with COPD demonstrated FDG activity in the intercostal muscles that was equal to or greater than the sternum and the tracer was demonstrated predominantly in the inferolateral chest wall (n = 8), the entire lateral chest wall (n = 2), the posteroinferior chest wall (n = 2), and the entire chest wall (n = 1). In all 13 patients with COPD who demonstrated FDG activity in the abdominal oblique muscles, the site of muscle activity was predominantly in the anteroinferior abdominal wall (n = 8), the lateral wall (n = 4), and the anterior wall (n = 1). In patients without known COPD, the frequency and intensity of uptake in the muscles were less than those with the disease. CONCLUSION: This study demonstrates the ability of FDG-PET imaging to assess muscle function in respiratory disorders and may prove to be of some value in further characterizing this disorder.
Abdominal Muscles↗
Reflux esophagitis secondary to chemotherapy detected by serial FDG-PET.
Explore the source record for details and available documents.
Aged↗
Sarcoidosis demonstrated by FDG PET imaging with negative findings on gallium scintigraphy.
Explore the source record for details and available documents.
Adult↗
Stability of cerebral blood flow measures using a split-dose technique with (99m)Tc-exametazime SPECT.
AIM: To determine whether there is stability of cerebral blood flow (CBF) measures using single photon emission computed tomography (SPECT) imaging in healthy controls in a test-retest split-dose paradigm. Such a paradigm is frequently used in the clinical and research setting to assess various brain states. METHODS: Five healthy volunteers underwent two brain SPECT scans after the administration of low and high doses of (99m)Tc-exametazime. The first SPECT scan was acquired approximately 30 min after the intravenous injection of approximately 259 MBq of (99m)Tc-exametazime. The second SPECT scan was acquired approximately 30 min after the intravenous injection of 925 MBq of (99m)Tc-exametazime. Both scans were acquired over approximately 30-45 min and the images were reconstructed using filtered backprojection, a low-pass filter and Chang's first-order attenuation correction. Values were obtained for regions of interest (ROIs) in major brain structures and normalized to whole brain activity. Counts on the second SPECT scan were also decay corrected for activity from the first scan. RESULTS: The results demonstrated a strong correlation between the low-dose and high-dose scans for all regions (r = 0.86, P<0.0001). Symmetries were preserved with a strong correlation between low-dose and high-dose scans (r = 0.70, P<0.0001). Finally, most regions demonstrated less than a 5% difference between the low-dose and high-dose scans. CONCLUSIONS: The results of this study demonstrate that the split-dose technique can be employed for clinical and research applications to measure CBF in different brain states using two SPECT scans on the same day.
Adult↗
Clinical applications of fluorodeoxyglucose--positron emission tomography in the management of malignant melanoma.
PURPOSE OF REVIEW: Malignant melanoma is the seventh most common newly diagnosed cancer among Americans. In most cases, melanoma is curable by means of surgical excision if diagnosed in early stages of the disease. The prognosis is linked directly to the initial stage at the time of diagnosis. Early diagnosis and accurate disease staging is important for appropriate treatment planning. This review focuses on clinical applications of positron emission tomography (PET) using F-fluorodeoxyglucose (FDG) in the management of patients with malignant melanoma. RECENT FINDINGS: Many investigators have studied the role of FDG-PET in the management of malignant melanoma. PET has been shown to have a strong role in detection of metastatic disease. FDG-PET can highlight metastases at unusual sites that are easily missed with conventional imaging modalities. It is more sensitive than computed tomography (CT) for detection of metastatic lesions in skin, lymph nodes, and abdomen. Despite the overall superiority of FDG-PET in the detection of melanoma metastases, it has limitations in detection of early-stage disease (stage I-II), small lung nodules, and brain metastases. Most of the false-negative FDG-PET results are due to micrometastases and lesions small than 10 mm. False-positive FDG-PET results are due to postsurgical inflammation, other inflammatory lesions, and some benign tumors. SUMMARY: FDG-PET is a metabolic, noninvasive imaging modality for detecting distant metastatic and recurrent melanoma. FDG-PET is of limited use in patients with early-stage disease and cannot replace sentinel node biopsy, which is much more sensitive in detecting microscopic lymph node metastases.
Fluorodeoxyglucose F18↗
FDG-PET imaging in primary bilateral adrenal lymphoma: a case report and review of the literature.
Primary adrenal lymphoma is an extremely rare entity. Only 70 cases have been reported in the English literature. Most of the patients are elderly men with bilateral adrenal masses without extraadrenal involvement. The most common presenting symptoms are fever, weight loss, lumbar pain, and/or symptoms of adrenal insufficiency. Of the cases reported, CT, ultrasound, and MRI were the imaging modalities used to describe the lesions. FDG PET has been used successfully to differentiate benign and malignant adrenal masses. The authors report a 67-year-old man diagnosed as having primary bilateral adrenal lymphoma and having no evidence of extraadrenal spread who was evaluated from the time of diagnosis to complete remission with FDG PET scanning. The literature of this unusual neoplasm is reviewed in detail.
Adrenal Gland Neoplasms↗
F-18 FDG positron emission tomography in non-Hodgkin lymphoma of the breast.
The breast is an uncommon site of development of extranodal non-Hodgkin lymphoma (NHL). Both primary and secondary involvement of the breast have been reported. A 36-year-old woman diagnosed with NHL underwent multimodality imaging for staging of the disease. CT of the chest revealed no significant abnormalities. Whole-body FDG PET imaging showed intense FDG uptake in the left breast. Cytologic examination confirmed breast involvement by diffuse large B-cell NHL. Although rare, breast involvement characterized by increased FDG uptake can occur in patients with lymphoma. This case highlights the role of FDG PET in patients with suspected lymphoma in dense breasts that can be missed by CT scan and mammogram.
Adult↗
Pelvic horseshoe kidney mimics sacral metastases on bone scan.
Explore the source record for details and available documents.
Bone Neoplasms↗
Radiation myelopathy visualized as increased FDG uptake on positron emission tomography.
A woman with a history of desmoid tumor involving the T9-T10 vertebrae was treated with local irradiation. After treatment, she developed tingling sensations in both legs. An FDG PET study demonstrated focally increased activity posterior to the vertebral bodies at the levels of T9-T10, which was vertical in orientation, corresponding to the location of the spinal cord at this level. This finding is consistent with the clinical suspicion of radiation myelopathy.
Adult↗
Detection of bone marrow metastases by FDG-PET and missed by bone scintigraphy in widespread melanoma.
The optimal management of patients with melanoma requires accurate imaging techniques that can screen the entire body for metastases. One of the most used tests for this purpose is bone scintigraphy. PET has been reported to be more sensitive than bone scintigraphy in some malignancies. In our case, FDG-PET was also superior to bone scintigraphy in detecting the extent of skeletal disease in a patient with melanoma. This is likely the result of the fact that metastasis to bone marrow may not result in bone reaction in certain conditions and therefore bone scans may remain negative despite skeletal involvement.
Adult↗
Intense esophageal FDG activity caused by Candida infection obscured the concurrent primary esophageal cancer on PET imaging.
Esophageal cancer frequently causes a focal intense FDG uptake on positron emission tomography (PET) imaging while esophagitis often results in a mild to moderate degree of FDG activity in a diffuse pattern. However, detection of an esophageal cancer can become difficult in the presence of a diffuse esophageal activity because of esophagitis. We present such case in which esophageal cancer superimposed by Candidal esophagitis is difficult to recognize on FDG PET images.
Candidiasis↗
Transiently increased MDP activity in the soft tissue of lower extremity caused by iliofemoral venous thrombosis.
Explore the source record for details and available documents.
Adolescent↗
Cerebral blood flow effects of pain and acupuncture: a preliminary single-photon emission computed tomography imaging study.
BACKGROUND: The purpose of this study was to investigate the cerebral blood flow changes associated with the analgesic effect of acupuncture in patients with chronic pain. METHODS: Seven patients presenting with a chronic pain syndrome and 5 healthy controls were included. All single-photon emission computed tomography (SPECT) scans were acquired with a uniform protocol. The patient group was injected with the radioisotope hexamethyl propyleneamine oxime (HMPAO) while experiencing their usual level of pain. A baseline scan was acquired approximately 20 minutes after administration of the HMPAO. The patient then underwent acupuncture therapy with needles placed in points specifically selected to relieve pain. When the pain improved, as determined by a 10-digit score for pain assessment, the patient was reinjected with HMPAO and imaged 20 minutes later for the acupuncture scan. The reference group also had a baseline and acupuncture scan, although the acupuncture itself was performed using a standardized set of needle points. RESULTS: The reference group participants were found to have significant increases in the thalamic and prefrontal cortex activity on the acupuncture scan compared to the baseline. The baseline scans of the pain patients showed significant asymmetric uptake in the thalami compared to controls. This asymmetry reversed or normalized after the acupuncture therapy. Significant correlations were observed between the change of activity in the prefrontal cortex and ipsilateral sensorimotor area. CONCLUSION: The results from these cases show that HMPAO-SPECT is capable of detecting changes in cerebral blood flow associated with pain and that acupuncture analgesia is associated with changes in the activity of the frontal lobes, brain stem, and thalami.
Acupuncture Analgesia↗
Small urine leak after renal transplantation: detection by delayed 99mTc-DTPA renography--a case report.
This case report involves a 45-y-old woman after cadaveric renal transplantation. The initial renal scan on the first postsurgical day showed normal findings. Subsequently, on the sixth postsurgical day, the patient had decreased urine output; 99mTc-diethylenetriaminepentaacetic acid renal scanning was performed again and did not show definite scintigraphic evidence of a urine leak. The patient's condition was not improving; renal scanning was repeated on day 20 and demonstrated a large photopenic region surrounding the superior, medial, and inferior aspects of the kidney. Delayed imaging was performed 2.5 h after injection of radiotracer, and activity was observed in the previously cold region.
Female↗