Biomedical subjects
Publications and source records attributed to Ravinder K Grewal.
Lung cancer is the most frequently occurring cancer in the world, and in the United States it is the second most common cancer diagnosed. Accurate staging by imaging can have a significant impact on appropriate treatment and surgical options. Familiarity with the different histologic subtypes of lung cancer and the typical and atypical appearances of lung cancer is vital. Radiologists serve a critical role in the diagnosis, staging, and follow-up of patients with lung cancer.
BACKGROUND: Complete staging of rhabdomyosarcoma is critical to deliver appropriate therapy. We evaluated the role of F-fluorodeoxyglucose positron emission tomography (PET) in the staging of patients with rhabdomyosarcoma. METHODS: Twenty-four patients with rhabdomyosarcoma had a PET scan during staging evaluation, before or within 13 days of initiation of therapy. PET was compared with computed tomography (CT), magnetic resonance imaging (MRI), bone scan, and pathology. RESULTS: Ninety-six sites were evaluated. All patients had positive PET scans at the primary site. Thirty-one PET positive sites at primary, regional, or distant sites were biopsied. Pathology in all 31 confirmed disease. Standardized uptake value for the primary site at diagnosis ranged from 2.4 to 12.7 (mean 6.4). At 23 sites, CT or MRI was equivocal for the detection of regional or distant spread. In these cases, a negative PET helped to exclude disease in 21 of 23 patients. PET failed to capture sites of disease visualized by CT, MRI, or bone scan at 10 sites. When comparing PET with the final clinical determination of disease extent, PET was 77% sensitive and 95% specific. CONCLUSIONS: These preliminary data indicate that PET is a useful adjunct in staging rhabdomyosarcoma. A prospective study of PET for staging of rhabdomyosarcoma is warranted.
Higher incidences of osteoporosis and osteopenia are found in cancer patients, particularly in women receiving aromatase inhibitors or with chemotherapy-induced ovarian failure, or in men with prostate cancer and androgen deprivation therapy. Therefore, management of long-term bone health is emerging as an important aspect of comprehensive cancer care. Patients with cancer typically have a number of additional risk factors for osteoporosis that should prompt screening, regardless of patient age or sex. Maintaining bone health requires a broad knowledge base, including understanding underlying bone metabolism and how it is affected by both cancer itself and the drugs used to treat cancer, the effect of chemotherapy-induced menopause on bone health, bone markers and imaging techniques used to assess bone health, therapeutic strategies to maintain bone health, and treatment of bone metastases, including surgery for pathologic fractures. Multiple members of the healthcare team may need to be involved in education and care of the patient. This report summarizes discussion of these and other issues regarding bone health and cancer care from the NCCN Bone Health and Cancer Care Task Force meeting in early 2006.
CONTEXT/OBJECTIVE: Approximately 15% of thyroid cancer patients develop subsequent metastases. The clinical course of patients with metastatic thyroid carcinoma is highly variable. We hypothesized that the metabolic activity of metastatic lesions, as defined by retention of 2-[(18)F]fluoro-2-deoxyglucose (FDG), would correlate with prognosis. DESIGN/PATIENTS: The initial FDG-positron emission tomography (PET) scans from 400 thyroid cancer patients were retrospectively reviewed and compared with overall survival (median follow-up, 7.9 yr). We examined the prognostic value of clinical information such as gender, age, serum thyroglobulin, American Joint Committee on Cancer (AJCC) stage, histology, radioiodine avidity, FDG-PET positivity, number of FDG-avid lesions, and the glycolytic rate of the most active lesion. RESULTS: Age, initial stage, histology, thyroglobulin, radioiodine uptake, and PET outcomes all correlated with survival by univariate analysis. However, only age and PET results continued to be strong predictors of survival under multivariate analysis. The initial American Joint Committee on Cancer stage was not a significant predictor of survival by multivariate analysis. There were significant inverse relationships between survival and both the glycolytic rate of the most active lesion and the number of FDG-avid lesions. CONCLUSIONS: FDG-PET scanning is a simple, expensive, but powerful means to restage thyroid cancer patients who develop subsequent metastases, assigning them to groups that are either at low (FDG negative) or high (FDG positive) risk of cancer-associated mortality. We propose that the aggressiveness of therapy for metastases should match the FDG-PET status.
UNLABELLED: The concentration of (18)F-FDG in the gastroesophageal junction (GEJ) and gastric antrum (GA) varies significantly from patient to patient. To document the reference range of uptake in patients, we reviewed the (18)F-FDG PET scans of patients with no documented gastroesophageal disease. METHODS: The medical records of patients undergoing PET/CT were reviewed. Patients with known gastric, pancreatic, or liver pathology were excluded. The peak standardized uptake value (SUV) for the GEJ and GA were measured in the remaining patients. The clinical record was also reviewed for gastroesophageal reflux disease (GERD) and previous chemotherapy. RESULTS: A total of 763 patients met the inclusion criteria (388 male and 375 female; mean age +/- SD, 57.4 +/- 17 y; range, 15-95 y). Images were recorded 68.2 +/- 11.8 min after injection of 558.7 +/- 35.1 MBq of (18)F-FDG. PET/CT was performed on a Discovery LS scanner for 373 patients and on a Biograph scanner for 390. The maximum SUV was less than 4 in 94.4% of patients. GEJ SUV measurements on the Discovery LS and on the Biograph did not significantly differ. During the 6 mo before the scan, 515 patients received no antineoplastic chemotherapy. Of the remaining 248, 137 received chemotherapy within 1 mo before the scan; 65, between 1 and 3 mo before the scan; and 46, between 3 and 6 mo before the scan. No significant differences were found between groups. GERD was documented in the records of 75 patients. Only 58 of these patients were treated with an antacid regimen. In 552 patients, GERD was not known to be present nor was antacid treatment used. An additional 136 patients had antacid treatment without specified gastric symptomatology. Patients with a history of GERD had a slightly higher but not statistically significant SUV peak in the stomach and particularly in the GEJ, except when compared with the group without associated antacid treatment (P = 0.049). CONCLUSION: In patients without a specific history of esophagogastric disease, a gastroesophageal maximum SUV less than 4 is usually not associated with gastroesophageal neoplasia.
State-of-the-art techniques have been used to measure key aspects of cardiovascular pathophysiology from the birth of radionuclide cardiovascular imaging. However, during the last 30 years, there have been few innovative imaging advances to further our understanding of the complex physiologic processes. Molecular imaging now offers an array of tools to develop advanced diagnostic approaches and therapies for patients with coronary artery disease and heart failure. For example, the enhanced understanding of the pathophysiology of atheroma makes it possible to identify vulnerable plaque based on its metabolic signature or the presence of excessive apoptosis. Because the metabolic and apoptotic signals are large, it is likely that even small lesions will be visible. Of the many approaches that are being developed, 2 tracers appear most likely to be tested in the near future: (1) [18F]-fluorodeoxyglucose, to determine macrophage metabolism; and (2) radiolabeled annexin, to measure apoptosis of the inflammatory cells. Using existing techniques such as perfusion imaging, appropriate patients can be selected for treatment with novel therapies, such as stem cell transplantation or vascular gene therapy. Using positron tomography in place of single photon imaging adds the capability for the measurement of absolute perfusion and perfusion reserve to the information on regional perfusion. Flow reserve detects global decreases in perfusion and refines the determination of lesion severity available from perfusion imaging.
UNLABELLED: The routine use of PET/CT fusion imaging in a large oncology practice has led to the realization that (18)F-FDG uptake into normal fat and muscle can be a common source of potentially misleading false-positive PET imaging in the neck, thorax, and abdomen. The goal of this study was to characterize this normal variant of (18)F-FDG uptake in terms of incidence and characteristic extent. METHODS: All body scans done on our PET/CT scanners in July and August 2002 were retrospectively reviewed. All cases in which increased (18)F-FDG uptake in the neck was not localized to lymph nodes or other obvious anatomic sites on the CT scans were included in this study. Sites of any unexplained (18)F-FDG uptake in the rest of the body were also recorded. RESULTS: A total of 863 PET scans (476 males, 387 females; age, 2-88 y; mean age, 57 y) were reviewed. The following distinctive patterns of nonpathologic (18)F-FDG activity were observed: (a) neck fat, 20 patients (2.3%); (b) paravertebral uptake, 12 patients (1.4%); (c) perinephric fat, 7 patients (0.8%); (d) mediastinal fat, 8 patients (0.9%); (e) normal musculature, 12 patients (1.4%). Patients showing paravertebral uptake, perinephric fat, and mediastinal fat were all associated with the neck fat pattern, singly or in combination. On the other hand, patients showing the normal musculature pattern did not show any of the other uptake. In this analysis, the incidence of (18)F-FDG uptake in sites other than the neck is restricted to the patient population with neck fat uptake and may be an underestimation of the true incidence. Neck fat is found predominantly in females, whereas normal musculature is usually seen in males (P < 0.01, Fisher exact test). Neck fat is also seen significantly more in the pediatric population (4/26 = 15%) than in the adult population (16/837 = 1.9%) (P < 0.01, Fisher exact test). CONCLUSION: Increased (18)F-FDG uptake is sometimes seen in individual muscles and in adipose tissue in the neck and shoulder region, axillae, mediastinum, and perinephric regions. There is also associated (18)F-FDG uptake in the intercostal spaces in the paravertebral regions. (18)F-FDG uptake in neck fat is more commonly seen in female patients and the pediatric population. The pattern of uptake as well as the age and sex distribution suggest that the (18)F-FDG in fat is in the brown adipose tissue. It is important to recognize this uptake pattern to avoid false interpretation of this benign normal variant as a malignant finding on (18)F-FDG PET scans.
PURPOSE: Tc-99m depreotide is a peptide analogue of a somatostatin receptor that preferentially binds to somatostatin receptors 2, 3, and 5. Many lung tumors may express these receptors to a greater extent than normal tissue. Tc 99m depreotide study is a noninvasive, receptor-specific imaging agent that is used to assess malignant versus benign single pulmonary nodules before biopsy. MATERIALS AND METHODS: Thirty-nine consecutive patients (15 men, 24 women), with mean age 56.6 years (range 39-86) underwent 42 studies. The single-photon emission computed tomographic scan of the chest and whole-body imaging were performed 2 hours after intravenous injection of Tc 99m depreotide (average dose, 24 mCi). The region of interest was drawn around each lesion, and the tumor-to-background ratio was measured. Images were classified as true positive when the tumor uptake and histopathology were concordant. The results were classified as true negative when there was no uptake in the absence of malignancy. The results were classified as false positive when there was uptake in areas other than tumor and were false negative when no uptake in the tumor was identified. The computed tomographic and pathological correlations were performed. RESULTS: The comparison of technetium Tc 99m depreotide imaging with computed tomographic study revealed a sensitivity of 1.0 versus 0.9, a specificity 0.43 versus 0.19, accuracy 0.71 versus 0.55, positive predictive value 0.64 versus 0.53, and negative predictive value 1.0 versus 0.67,. The tumor-to-background ratio ranged from 1.15 to 3.77. There was no relationship between the histology and the intensity of tumor uptake. The tumor uptake was high in sites of acute and active inflammation. CONCLUSION: Technetium Tc 99m depreotide imaging is a sensitive imaging modality with better specificity and negative predictive value than computed tomography. There is no relationship between tumor uptake and differentiation of the tumor. We recommend a technetium Tc 99m depreotide study forthe evaluation of solitary pulmonary nodules, especially when positron emission tomography is not available before biopsy.
PURPOSE: The role of Ga 67 in the evaluation of Hodgkin's disease has been widely established. Tl 201 has been used to evaluate a wide variety of malignant lesions. This prospective study was performed to evaluate the role of Tl 201 imaging in Hodgkin's disease at the time of initial presentation and in the assessment of response to therapy, relapse, and remission. METHODS: Fifty-one consecutive patients (23 female, 28 male) with known Hodgkin's disease underwent 111 Tl 201 and Ga 67 studies. The age range was 16-56 years (mean age, 34.7 years). The histopathologies included nodular sclerosis (in 31 cases), mixed cellularity (in 12), lymphocytic predominant (in five), lymphocytic depletion (in one), and unknown (in two). All patients underwent whole-body imaging after intravenous injection of 3 mCi of Tl 201 chloride and 10 mCi of Ga 67 citrate. Comparison with Ga 67 imaging, anatomical imaging (computed tomography and/or magnetic resonance imaging), and clinical correlation were performed. RESULTS: The combined analysis of all various histologies demonstrated that a comparison of Tl 201 with Ga 67 scintigraphy revealed a sensitivity of 0.76 versus 0.89; a specificity of 0.96 versus 0.73, an accuracy of 0.86 versus 0.81, a positive predictive value of 0.95 versus 0.77, and a negative predictive value of 0.81 versus 0.87. Tl 201 imaging was similar in sensitivity, specificity, and accuracy among the nodular sclerosis and the mixed-cellularity Hodgkin's disease. CONCLUSION: Tl 201 imaging offers more specificity with a higher positive predictive value in the diagnosis of Hodgkin's disease. The Ga 67 study is more sensitive than Tl 201 in the detection of disease. There is no significant difference in accuracy and negative predictive value between the two studies. Therefore, we recommend Tl 201 imaging in the initial evaluation and assessment of patients' response to radiation therapy and/or chemotherapy.