[show abstract][hide abstract] ABSTRACT: The objective of this study was to determine if a correlation exists between the effective renal plasma flow (ERPF) and the extraction fraction (EF) using 99mTc MAG3 in children. This EF has been previously described with 9mTc DTPA. However, the renal imaging agent of choice has become 9mTc MAG3.
The study was approved by The Children's Hospital of Philadelphia's institutional review board. Informed consent was also obtained A retrospective study of 29 children (16 males, 13 females) of ages 1 month to 19.5 years who underwent 99mTc MAG3 renal scintigraphy from September 2001 to December 2001 was analysed. EF values were calculated with and without attenuation correction in each kidney by determining the counts in a region of interest, correcting for background and comparing the counts with the injected dose. The EF was compared to the ERPF calculated using the Schlegel's method. The correlation between the EF and the ERPF corrected and non-corrected for soft tissue attenuation, were determined and were identified by using linear regression analysis.
There was significant correlation between the ERPF and the EF with (r = 0.62, p < 0.05 on the left, r = 0.51, p = 0.005 on the right) than without attenuation correction (r = 0.54, p = 0.003 on the left, r = 0.42, p = 0.022 on the right).
These results indicate a correlation of the ERPF calculated using the Schlegel's method with EF obtained from a 99mTc MAG3 renal scintigraphy. The EF may be the good alternative parameter for calculation of renal function, potentially more practical in pediatric patient and the ERPF for 99mTc MAG3 using the established software program based on Schlegel's formula.
Journal of the Medical Association of Thailand = Chotmaihet thangphaet 10/2006; 89(9):1479-86.
[show abstract][hide abstract] ABSTRACT: 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).
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.
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.
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.
Clinical Nuclear Medicine 04/2005; 30(3):159-64. · 2.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: There are reports and controversy in the literature of supranormal (defined as >55%) differential renal function (DRF) in the hydronephrotic kidney in children with unilateral hydronephrosis. It is not confirmed whether supranormal DRF is an artifact or a true finding. In patients in whom the relative renal function deteriorates, relief of obstruction becomes surgically necessary and if this artifact can be removed. Supranormal function in an obstructed kidney is confusing and there is no consensus on how to manage these patients. There is no agreement if this is a true entity or an artifact. We wanted to address this issue by reporting our experience.
We reviewed all the consecutive cases from August 2000 to October 2001 who were studied in our center with the diagnosis of unilateral renal obstruction for confirmation or evaluation of DRF. All patients had MAG-3 studies that were interpreted by experienced nuclear medicine physicians. The DRF were measured within the first to second minute of the MAG-3 injection. Regions of interest were drawn by the imaging software and the images were corrected for background counts by drawing regions of interest 2 pixels away from the edge of the renal cortex.
Fifty-seven patients were confirmed to be obstructed unilaterally; 41 (72%) patients had obstructive lesions in the left kidney and 16 (28%) in the right kidney. There was no case of supranormal DRF in the obstructed kidneys in our study.
The supranormal renal function, as noted in some reports in the literature, was not seen in any patients at our institution. We believe that this entity is an artifact and can be avoided by using MAG-3 and projecting regions of interest by computer software; we plan to start analyzing multiple algorithms in phantoms with different ROI selection for background analysis.
Clinical Nuclear Medicine 07/2004; 29(7):410-4. · 2.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: To evaluate the biodistribution of therapeutic (131)I-metaiodobenzylguanidine (MIBG) and assess the sensitivity of diagnostic versus therapeutic (131)I-MIBG scans to detect metastatic disease.
This retrospective study included 44 diagnostic and post-therapy scans (PTS) in 18 children with neuroblastoma treated with (131)I-MIBG (2.0-33.1 GBq). The findings of diagnostic scans (DS) (2.6-44.4 MBq) were compared to those of corresponding PTS.
In terms of biodistribution, the PTS identified (131)I-MIBG activity in one or more patients in the following regions not detected on the DS: nasal mucosa, cerebellum, central brain, adrenals, spleen, kidneys, thyroid, salivary glands, lower halves of the lungs, bladder, bowel, and an incisional scar. Conversely, the DS identified activity in the thorax, heart, kidneys, and bladder each in one patient without being visualized on the PTS. In terms of sensitivity to detect metastatic disease, 210 lesions were seen on the PTS compared to 151 on the DS. The PTS demonstrated sites of disease not evident in the DS in 16 cases.
The biodistribution of (131)I-MIBG is different using therapeutic doses as compared to pre-therapy doses. (131)I-MIBG imaging following high therapeutic doses often reveals sites of occult metastatic disease that may be clinically relevant.
Pediatric Blood & Cancer 04/2004; 42(3):268-74. · 2.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: It is known that following a traumatic fracture or surgical intervention, bone scintigraphy reveals positive results for an extended period of time, posing a challenge when evaluating patients for possible malignancy or superimposed osteomyelitis. Previous reports indicate that acute fractures can also result in increased fluorine-18 fluorodeoxyglucose (FDG) accumulation and therefore cause difficulties when patients are evaluated for other indications by FDG-PET. The purpose of this study was to assess the pattern and time course of abnormal FDG uptake following traumatic or surgical fracture. A total of 1,517 consecutive patients who underwent whole-body FDG-PET imaging were retrospectively studied. A history of fractures or orthopedic intervention was obtained from an interview prior to scanning. The FDG-PET results were compared with the results of other imaging studies, including bone scans, radiographs, CT, and MRI, as well as surgical pathology reports. Thirty-seven patients with a known date of traumatic or surgical fracture were identified. Among these, 14 had fractures or surgery within 3 months prior to FDG-PET, while 23 had fractures or surgical intervention greater than 3 months prior to FDG-PET. FDG-PET showed no abnormally increased uptake at the known fracture or surgical sites in 30 of these patients. Notably, in the 23 patients with fractures more than 3 months old, all but one showed no abnormally increased uptake. Furthermore, the positive FDG uptake in this exception was a result of complicating osteomyelitis. In the 14 patients with a history of fracture less than 3 months old, only six had abnormally increased FDG uptake. Following traumatic or surgical fractures, FDG uptake is expected to be normal within 3 months unless the process is complicated by infection or malignancy.
European journal of nuclear medicine and molecular imaging 09/2003; 30(8):1096-103. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to determine the actual standardized uptake value (SUV) by using the lesion size from computer tomography (CT) scan to correct for resolution and partial volume effects in positron emission tomography (PET) imaging. This retrospective study included 47 patients with lung lesions seen on CT scan whose diagnoses were confirmed by biopsy or by follow up CT scan when the PET result was considered negative for malignancy. Each lesion's FDG uptake was quantified by the SUV using two methods: by measuring the maximum voxel SUV (maxSUV) and by using the lesion's size on CT to calculate the actual SUV (corSUV). Among small lesions (2.0 cm or smaller on CT scan), ten were benign and 17 were malignant. The average maxSUV was 1.43+/-0.77 and 3.02+/-1.74 for benign and malignant lesions respectively. When using an SUV of 2.0 as the cutoff to differentiate benignity and malignancy, the sensitivity, specificity, and accuracy were 65%, 70%, and 67% respectively. When an SUV of 2.5 was used for cutoff, the sensitivity, specificity, and accuracy were 47%, 80%, and 59% respectively. The average corSUV was 1.65+/-1.09 and 5.28+/-2.71 for benign and malignant lesions respectively. Whether an SUV of either 2.0 or 2.5 was used for cutoff, the sensitivity, specificity, and accuracy remained 94%, 70%, and 85% respectively. The only malignant lesion that was falsely considered benign with both methods was a bronchioalveolar carcinoma which did not reveal any elevated uptake of fluorine-18 fluorodeoxyglucose (FDG). Of the large lesions (more than 2.0 cm and less than 6.0 cm), one was benign and 19 were malignant and the corSUV technique did not significantly change the accuracy. It is concluded that measuring the SUV by using the CT size to correct for resolution and partial volume effects offers potential value in differentiating malignant from benign lesions in this population. This approach appears to improve the accuracy of FDG-PET for optimal characterization of small lung nodules.
European journal of nuclear medicine and molecular imaging 01/2003; 29(12):1639-47. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: The role of the fluorodeoxyglucose (FDG) technique positron emission tomography (PET) is well established in the management of patients with lung cancer. Increasingly, it is becoming evident that FDG-PET can be effectively employed to diagnose a variety of benign pulmonary disorders. Knowledge of such applications further expands the domain of this powerful modality and further improves the ability to differentiate benign from malignant diseases of the chest. We describe pertinent technical factors that substantially contribute to optimal imaging of the thoracic structures. Particularly, the complementary role of attenuation correction (AC) to that of non-AC images is emphasized. We further outline the need for and the state of the art for co-registration of PET and anatomic images for diagnostic and therapeutic purposes. We then review patterns of physiologic uptake of FDG in thoracic structures, including the lung, the heart, the aorta and large arteries, esophagus, thymus, trachea, thoracic muscles, bone marrow, and joints and alterations following radiation therapy to the thorax. A great deal of information is provided with regard to differentiating benign from malignant nodules and in particular, we emphasize the role of dual time point imaging and partial volume correction for accurate assessment of such lesions. Following a brief review of the diagnostic issues related to the assessment of mediastinal adenopathies, the role of FDG-PET imaging in environment-induced lung diseases, including pneumoconiosis, smoking, and asthma are described. A large body of information is provided about the role of this technology in the management of patients with suspected infection and inflammation of the lungs such as acquired immunodeficiency syndrome, fever of unknown origin, sarcoidosis, chronic granulomatous disease and monitoring the disease process and response to therapy. Finally, the value of FDG-PET in differentiating benign from malignant diseases of the pleura including asbestosis-related disorders is described at the conclusion of this comprehensive review.
Seminars in Nuclear Medicine 11/2002; 32(4):293-321. · 3.82 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hip arthroplasty is a common surgical procedure, but the diagnosis of infection associated with hip arthroplasty remains challenging. Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown to be a promising imaging modality in settings where infection is suspected. However, inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations, which may erroneously be interpreted as sites of infection. The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time. Firstly, in a prospective study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time. Three FDG-PET scans were performed in each patient at about 3, 6 and 12 months post arthroplasty. Secondly, in a retrospective analysis, the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were reviewed. The history of arthroplasty and FDG-PET findings in the hip region were reviewed for this study. Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis. During the entire study period, all nine patients enrolled in the prospective study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur. Among the patients reviewed in the retrospective study, 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion. The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months (mean+/-SD: 80.4+/-86.2 months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be noted around the femoral head or neck portion of the prosthesis. The average time interval between arthroplasty and FDG-PET scan in these patients was 71.3 months. In only four prostheses (19%, 4 of 21) was no abnormally increased FDG uptake seen around the prostheses or adjacent sites. The average time interval in these patients was 114.8 months. It is concluded that following hip arthroplasty, non-specifically increased FDG uptake around the head or neck of the prosthesis persists for many years, even in patients without any complications. Therefore, to minimize the number of false-positive results for infection with PET studies obtained to evaluate a painful hip prosthesis, caution should be exercised when interpreting FDG uptake around the head or neck portion of the prosthesis.
European journal of nuclear medicine and molecular imaging 11/2002; 29(10):1328-33. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Fluorodeoxyglucose (FDG) positron emission tomographic (PET) imaging has been used extensively to diagnose cancer with high rates of sensitivity and specificity. One of its applications is to distinguish benign from malignant pulmonary nodules. It is common to observe colonic uptake on whole-body FDG-PET images. Because patients with lung cancer also tend to be in the age group with the highest incidence of colon cancer, the authors tried to assess the efficacy of FDG-PET for detecting occult colon cancer in patients referred for the evaluation of lung nodules.
The records of 500 consecutive patients referred for the evaluation of pulmonary nodules were reviewed retrospectively. Among the patients, 197 had no previous clinical or radiographic evidence of abnormalities in the gastrointestinal tract, and none had been found to have any cancer before undergoing an FDG-PET study. All colon lesions were verified either by histologic analysis or by clinical course.
Among the 197 patients analyzed, 59 had diffuse colonic uptake in various segments of the colon. Seventeen of the patients had focal colonic uptake, five of which were proved to be colon cancer.
The routine use of FDG PET to characterize lung lesions significantly increases the probability of detecting unexpected extrathoracic disease. In these patients, the incidental finding of colon cancer had an important effect on their treatment and may prove to be very cost-effective.
Clinical Nuclear Medicine 10/2002; 27(9):628-32. · 2.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: 18F-FDG PET has reached widespread application in the assessment of pulmonary nodules. This study compares the diagnostic accuracy of standard 18F-FDG PET scanning with those of dual time point 18F-FDG PET scanning.
Thirty-six patients (21 women, 15 men; mean age, 67 y; range, 36-88 y) with 38 known or suspected malignant pulmonary nodules underwent PET of the thorax at 2 time points: scan 1 at 70 min (range, 56-110 min) and scan 2 at 123 min (range, 100-163 min) after the intravenous injection of 2.5 MBq 18F-FDG per kilogram of body weight. All scanning was performed on a dedicated C-PET scanner. The mean interval between the scans was 56 min (range, 49-64 min). Regions of interest were overlaid onto each fully corrected image in the areas of the radiographically known lung densities. The standardized uptake values (SUVs) were calculated for both time points.
Surgical pathology and follow-up revealed 19 patients with 20 malignant tumors, whereas 16 patients had benign lesions. The tumor SUVs (mean +/- SD) were 3.66 +/- 1.95 (scan 1) and 4.43 +/- 2.43 (scan 2) (20.5% +/- 8.1% increase; P < 0.01). Four of 20 malignant tumors had SUVs of <2.5 on scan 1 (range, 1.12-1.69). Benign lesions had SUVs of 1.14 +/- 0.64 (scan 1) and 1.11 +/- 0.70 (scan 2) (P = not significant). Standard PET scanning (single time point) with a threshold SUV of 2.5 (at time point 1) reached a sensitivity of 80% and a specificity of 94%; dual time point scanning with a threshold value of 10% increase between scan 1 and scan 2 reached a sensitivity of 100% with a specificity of 89%.
Dual time point 18F-FDG PET results in a very high sensitivity and specificity for detection of malignant lung tumors.
Journal of Nuclear Medicine 07/2002; 43(7):871-5. · 5.77 Impact Factor