Biomedical subjects

D Delbeke

Publications and source records attributed to D Delbeke.

At least 37 records · Page 2Linked to original sources

PubMed1998

Prospective investigation of positron emission tomography in lung nodules.

PURPOSE: Solitary pulmonary nodules (SPNs) are commonly identified by chest radiographs and computed tomography (CT). Biopsies are often performed to evaluate the nodules further. An accurate, noninvasive diagnostic test could avoid the morbidity and costs of invasive tissue sampling. We evaluated the ability of fluorine-18 deoxyglucose positron emission tomography (FDG-PET) to discriminate between benign and malignant pulmonary nodules in a prospective, multicenter trial. METHODS: Eighty-nine patients who had newly identified indeterminate SPNs on chest radiographs and CT were evaluated with FDG-PET. PET data were analyzed semiquantitatively by calculating standardized uptake values (SUVs) as an index of FDG accumulation and also by a visual scoring method. PET results were compared with pathology results. RESULTS: Sixty SPNs were malignant and 29 were benign. Using SUV data, PET had an overall sensitivity and specificity for detection of malignant nodules of 92% and 90%. Visual analysis provided a slightly higher, but not statistically significant, sensitivity of 98% and lower specificity of 69%. For SPNs < or = 1.5 cm (34 of 89), the sensitivity and specificity of SUV and visual analysis were 80% and 95% and 100% and 74%, respectively. CONCLUSION: FDG-PET can accurately characterize indeterminate SPNs. PET imaging provides a noninvasive method to evaluate indeterminate SPNs, which can reduce the need for invasive tissue biopsy.

Aged↗

PubMed1998

Hepatocellular carcinoma outcomes based on indicated treatment strategy.

Hepatocellular carcinoma (HCC) in Western populations historically has been associated with poor survival. In this study, we conducted a 7-year retrospective analysis of patients evaluated at our institution with HCC to determine the effects of newer treatment strategies on outcome. During the period of study, 117 patients [86 (74%) male; mean age, 59 years (range, 16-85)] were evaluated with treatment as follows: surgical resection in 22 (19%), chemoembolization with or without systemic chemotherapy in 40 (35%), systemic treatment alone in 16 (13%), orthotopic liver transplantation in 8 (7%), and supportive care only in 31 (26%). Sixty-nine patients (59%) had documented cirrhosis, with hepatitis C being the most common cause in 27 of 69 (39%). In patients receiving no treatment, median survival was just under 3 months, with only two 1-year survivors. Patients with orthotopic liver transplantation had 1-, 2-, and 3-year survival rates of 87, 87, and 58 per cent compared with 69, 52, and 43 per cent in surgically resected patients. Survival after chemoembolization was 35, 20, and 11 per cent at 1, 2, and 3 years, whereas survival after systemic chemotherapy was 30 and 15 per cent at 1 and 2 years, respectively. One-year survival was improved in noncirrhotic patients compared with cirrhotics (47% vs 29%; P < 0.05) but was no different in patients younger than 55 years compared with older patients (38% vs 38%). When possible, surgical treatment strategies offer superior survival.

Adolescent↗

PubMed1997

A simplified intravenous glucose loading protocol for fluorine-18 fluorodeoxyglucose cardiac single-photon emission tomography.

The myocardial uptake of fluorine-18 fluorodeoxyglucose (FDG) has emerged as the most sensitive and specific technique for the assessment of myocardial viability. With the development of FDG single-photon emission tomography (SPET) and dual head coincidence imaging, a hindrance to the widespread clinical use of FDG cardiac imaging is the complexity of the preinjection glucose loading necessary for obtaining interpretable myocardial FDG scans. In a population of 209 patients undergoing dual-isotope single acquisition (DISA) FDG/sestamibi (MIBI) SPET, we describe the improvements in both image quality and time efficiency using a new short, simple glucose/insulin/potassium (GIK) infusion protocol prior to FDG injection as compared to a conventional oral glucose loading protocol. DISA FDG/MIBI SPET scans were performed in 111 nondiabetic patients after oral loading with 50 g of glucose (group 1). Ninety-eight consecutive nondiabetic patients were subsequently scanned following preparation with a fixed-concentration GIK infusion administered at a standardized rate (group 2). A three-point grading scale was used to assess image quality. The time to FDG injection following glucose administration was significantly shorter for the group 2 patients (39.9+/-15.6 min; range 20-105 min) than for the group 1 patients (99.5+/-30.3 min; range 56-270 min) (P<0.0001), representing a 1-h decrease in patient preparation time. More of the group 1 patients (n=30; 27%) required supplemental intravenous boluses of regular insulin than did the group 2 patients (n=13; 13%) (P<0.02). There were more excellent and good quality graded images using the GIK method (group 2) than the more traditional oral loading protocol (group 1) (P<0.02). Nine of 111 scans (8%) in group 1 were uninterpretable, whereas only one of 98 scans (1%) in group 2 was uninterpretable. Standardized infusion of a fixed concentration of GIK prior to FDG administration and continued during myocardial FDG uptake is an effective yet simple method of obtaining consistently good to excellent quality FDG SPET cardiac scans. It is preferable to conventional oral glucose loading due to decreased patient preparation time and improved image quality. The technique is safe and should improve both the clinical use and the cost-effectiveness of FDG SPET imaging for the identification of injured but viable myocardium.

Case-Control Studies↗

PubMed1997

Recurrent gallbladder carcinoma at laparoscopy port sites diagnosed by positron emission tomography: implications for primary and radical second operations.

Inapparent gallbladder carcinoma discovered by histologic examination following 1 per cent of cholecystectomies generates a difficult clinical problem. There is evidence that radical resection can prolong survival, especially for locally advanced (> or = PT2, according to the Union International Centre Cancer pathologic T classification) lesions. Case reports of recurrence at port sites after laparoscopic cholecystectomy add another aspect to the management difficulty. A 64-year-old woman underwent laparoscopic cholecystectomy for biliary colic. Histologic evaluation revealed an incidental adenocarcinoma, stage pT3. Radical resection with curative intent occurred 11 days later, including mesohepatectomy, skeletonization resection of the common bile duct with en bloc lymph node dissection, and bilateral Roux-en-Y hepaticojejunostomies. There was no tumor identified in the re-excision specimen (T3N0M0). At 7-month follow-up, the patient presented with nodules in the right subcostal area and in the periumbilical incision. Positron emission tomography demonstrated carcinoma at both sites. Biopsy confirmed metastatic gallbladder carcinoma. This case emphasizes the significance of tumor seeding at port sites during laparoscopy. An open technique is indicated if carcinoma is suspected. To avoid dissemination of unsuspected carcinoma during routine laparoscopic procedures, isolation techniques must be applied. The benefit of radical resection was clearly thwarted in this case, and resection of port sites at the time of reoperation is warranted. Finally, positron emission tomography scan is useful in delineating the recurrence of gallbladder carcinoma and its extent.

Adenocarcinoma↗

PubMed1997

Staging recurrent metastatic colorectal carcinoma with PET.

UNLABELLED: Accurate detection of recurrent colorectal carcinoma remains a diagnostic challenge. The purposes of this study were to assess the accuracy of 18FDG-PET in patients with recurrent colorectal carcinoma in detecting liver metastases compared with computed tomography (CT) and CT portography, detecting extrahepatic metastases compared with CT and evaluating the impact on patient management. METHODS: Fifty-two patients previously treated for colorectal carcinoma presented on 61 occasions with suspected recurrence and underwent 18FDG-PET of the entire body. PET, CT and CT portography images were analyzed visually. The final diagnosis was obtained by pathology (n = 44) or clinical and radiological follow-up (n = 17). The impact on management was reviewed retrospectively. RESULTS: A total of 166 suspicious lesions were identified. Of the 127 intrahepatic lesions, 104 were malignant, and of the 39 extrahepatic lesions, 34 were malignant. Fluorine-18-fluorodeoxyglucose imaging was more accurate (92%) than CT and CT portography (78% and 80%, respectively) in detecting liver metastases and more accurate than CT for extrahepatic metastases (92% and 71%, respectively). Fluorine-18-fluorodeoxyglucose detected unsuspected metastases in 17 patients and altered surgical management in 28% of patients. CONCLUSION: These data identify that 18FDG-PET is the most accurate noninvasive method for staging patients with recurrent metastatic colorectal carcinoma and plays an important role in management decisions in this setting.

Adenocarcinoma↗

PubMed1996

Positron emission tomography with F-18-fluorodeoxyglucose to evaluate the results of hepatic chemoembolization.

BACKGROUND: Positron emission tomography (PET) using F-18-flurodeoxyglucose (18FDG) is an imaging modality allowing direct evaluation of cellular glucose metabolism. The purpose of this study was to examine the role of 18FDG-PET in monitoring chemoembolization therapy of patients with liver metastases from adenocarcinoma. METHODS: Thirty-four hepatic lesions in 4 patients were evaluated with 18FDG-PET before and 2-3 months after interventional therapy. All patients underwent transcatheter arterial chemoembolization. A total of nine PET studies were performed. Semiquantitative measurement of the metabolic activity of the lesions was performed using the standard uptake value (SUV) of 18FDG. Comparison was performed between sequential PET scans using Student's t test for paired data analysis. The PET findings were also compared with tumor marker levels measured at the time of the PET scans. RESULTS: Twenty-five of 34 lesions had decreased 18FDG uptake (SUV = 8 +/- 2 vs. 3 +/- 1; P < 0.00001), as expected in successful tumor chemoembolization. These findings were associated with a significant decrease in serum tumor marker levels (86 +/- 4%; P < 0.05) after treatment. However, there were 3 new lesions, and 6 of the 34 lesions demonstrated persistent or increased 18FDG uptake after treatment (SUV = 8 +/- 2 vs. 13 +/- 3; P < 0.05), consistent with the presence of residual viable tumor. These findings led to further interventional therapy in all patients. CONCLUSIONS: 18FDG-PET allows monitoring of response to treatment with hepatic chemoembolization in patients with liver metastases from adenocarcinoma. PET is a useful diagnostic tool and has the potential to be used to guide further interventional therapy.

Adenocarcinoma↗

PubMed1996

Positron emission tomography to stage suspected metastatic colorectal carcinoma to the liver.

BACKGROUND: Accurate detection of recurrent colorectal carcinoma remains a clinical challenge. Positron emission tomography (PET) using 18F-fluorodeoxyglucose (18FDG) is an imaging technique that allows direct evaluation of cellular metabolism. 18F-fluorodeoxyglucose PET was compared to computed tomography (CT) and CT portography for staging metastatic colorectal carcinoma. PATIENTS AND METHODS: Twenty-four patients previously treated for colorectal carcinoma who had suspected recurrence to the liver underwent an 18FDG PET scan of the entire body. All patients had either a CT scan of the abdomen (n = 17), a CT portogram (n = 18), or both (n = 11). The final diagnosis was obtained by tissue pathology in 19 patients and clinical follow-up in 5 patients. RESULTS: A total of 60 suspicious lesions were identified. Of the 55 intrahepatic lesions, 39 were malignant and 16 were benign. Of the 5 extra-hepatic lesions, 4 were malignant. The 18FDG PET imaging had a higher accuracy (93%) than CT and CT portography (both 76%) in detecting metastatic disease to the liver, and detected unsuspected extrahepatic recurrence in 4 patients. Although the sensitivity of 18FDG PET (90%) was slightly lower than that of CT portography (97%), the specificity was much higher (100% versus 9%), including postsurgical sites. 18FDG PET altered surgical plans in 6 (25%) of 24 patients. CONCLUSIONS: 18FDG PET is extremely useful in staging patients with suspected metastatic colorectal carcinoma to the liver.

Colorectal Neoplasms↗

PubMed1996

Postsurgical outcome of patients with uncontrolled complex partial seizures and temporal lobe hypometabolism on 18FDG-positron emission tomography.

RATIONAL AND OBJECTIVE: The purpose of this study is to evaluate the relation between a focus of temporal lobe hypometabolism, including comparison between mesial and lateral asymmetry on fluorine-18-labeled-deoxyglucose-positron emission tomography (18FDG-PET) and surgical outcome in patients with uncontrolled partial seizures. METHODS: Case histories, electroencephalogram (EEG) findings, radiographic findings, and surgical outcome (36 +/- 11 months of follow-up) were reviewed in 38 consecutive patients who had a interictal 18FDG-PET scan and subsequent temporal resection. RESULTS: Among the 36 patients who had a temporal lobe focus of hypometabolism (more than 15% asymmetry to contralateral side), 61% (22 of 36) became seizure-free, 33% (12 of 36) markedly improved and 6% (2 of 36) did not improve. The focus of hypometabolism on PET was in agreement with the epileptic focus on the noninvasive EEG in 30 of 36 patients and in 19 of the 22 patients who underwent an invasive EEG. The asymmetry index for the mesial temporal lobe was significantly higher in the group of patients who became seizure-free compared with the other patients. CONCLUSION: This study confirms that a focus of interictal temporal hypometabolism on PET is associated with marked improvement of seizure control after surgery in 94% (34 of 36) of the patients. Hypometabolism in the mesial temporal lobe appears to be associated with a seizure-free outcome.

Adolescent↗

PubMed1996

Detection of malignancies with SPECT versus PET, with 2-[fluorine-18]fluoro-2-deoxy-D-glucose.

PURPOSE: To compare single photon emission computed tomography (SPECT) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) and positron emission tomography (PET) with FDG to evaluate malignancies. MATERIALS AND METHODS: PET and SPECT, with fluorine-18 sodium fluoride, were performed sequentially in a cylindric phantom that contained different size spheres with activity ratios of 5:1, 10:1, and 15:1. PET and SPECT were also performed in 24 patients with known or suspected malignancies. RESULTS: Sensitivities of PET and SPECT were 2,238 cpm/microCi (82.8 cpm/MBq) and 129 cpm/microCi (4.8 cpm/MBq), respectively (reconstructed spatial resolution, 7 and 17 mm, respectively [13-cm radius of rotation]). In the phantom studies, lesions of 1.5 and 1.3 cm or more in diameter were detected with a ratio of 5:1 and 10:1, respectively, and an information density of 150 counts per square centimeter. At FDG PET, 46 hypermetabolic lesions consistent with tumor were depicted in patients; at FDG SPECT, 36 (78%) were depicted. Sensitivity of FDG SPECT was 92% for detection of malignancies 1.8 cm or more in diameter seen at FDG PET. CONCLUSION: Findings at FDG SPECT can help differentiate benign from malignant lesions.

Adult↗

PubMed1996

Somatostatin receptor imaging: predictive and prognostic considerations.

Compared with other imaging modalities and clinical investigation, the 111In-pentetreotide scan identified additional metastatic disease sites in 12 carcinoid patients and 2 occult primaries, and influenced the therapeutic outcome in 36 patients [29 carcinoids, 2 atypical carcinoids, 3 cancers of unknown primaries (CUPs) and 2 medullary thyroid carcinomas (MCTs)]. No adverse reactions were noted. Somatostatin receptors were detected in 59/60 carcinoid patients, 3/4 atypical carcinoid patients, 0/2 MCT patients, and 0/3 cases of CUP. Somatostatin receptor presence is underestimated in some patients using standard hormonal response criteria rather than scintigraphy. 18 patients with metastatic carcinoids who underwent 111In-pentetreotide scanning were all somatostatin receptor positive. Their mean (+/- SE) 5-hydroxyindoleacetic acid (5-HIAA) suppression with octreotide therapy was -53% (+/- 6%). 8 patients had < 50% and 10 had > 50% 5-HIAA suppression (ranges: -4 to -47% and -58 to -94%, respectively). To investigate the effect of somatostatin analogues on survival, 90 consecutive cases of carcinoid syndrome patients treated during the somatostatin analogue era were reviewed. Survival according to primary site was 12.01, 18.29 and 6.05 years (overall median 12.01 years) for patients with foregut, midgut and unknown primaries, respectively. The difference from historical controls is substantial (67 vs. 18% 5-year survival), although our series is neither prospective nor randomised. The heterogeneity in patient and tumour response to somatostatin analogue therapy is discussed.

Carcinoid Tumor↗

PubMed1996

Evaluation of pulmonary lesions with FDG-PET. Comparison of findings in patients with and without a history of prior malignancy.

STUDY OBJECTIVE: The purpose of this study was to evaluate the accuracy of positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) in differentiating benign from malignant pulmonary lesions both in patients with and without a history of prior malignancy. DESIGN: Forty-eight consecutive patients with pulmonary lesions suspicious for malignancy underwent FDG-PET scanning. Group 1 included 27 patients without and group 2 included 21 patients with a history of malignancy. Pathologic proof of diagnosis was obtained for 32 patients and 16 patients were followed up clinically and radiographically for at least 6 month. The standard uptake ratio (SUR) and the lesion to background (L/B) ratio were determined in 45 patients. SETTING: Vanderbilt University Medical Center. RESULTS: In group 1, the average SUR and L/B ratio for malignant lesions (n=14) were 8.9 +/- 4.9 and 20.6 +/- 14.2, respectively. For benign lesions (n=12), the average SUR was 3.3 +/- 3.2 and L/B ratio was 5.2 +/- 5.5. In group 2, the average SUR and L/B ratio for malignant lesions were not significantly different from group 1. Using either a SUR greater than 2.5 or L/B ratio greater than 5 as an cutoff level to differentiate benign and malignant lesions, the sensitivity and negative predictive value in both groups were 100%. There were five false-positive studies in group 1 and one in group 2, including tuberculosis (n=2), a granulomatous lesion (n=1), an inflammatory lesion (n=1), a schwannoma (n=1), and a fibrous mesothelioma (n=1). The overall accuracy was 88%, 81% in group 1, and 95% in group 2. CONCLUSION: FDG-PET can identify malignant pulmonary lesions both in patients without and with a history of prior malignancy with a high sensitivity and negative predictive value for lesions greater than 1 cm (100% in this study). High FDG uptake by some inflammatory processes and benign tumors may cause false-positive results. Semiquantitative evaluation using SUR or L/B ratio provides similar accuracy.

Adult↗

PubMed1995

Evaluation of myocardial ischemia using a rest metabolism/stress perfusion protocol with fluorine-18 deoxyglucose/technetium-99m MIBI and dual-isotope simultaneous-acquisition single-photon emission computed tomography.

OBJECTIVES: This study sought to develop a dual-isotope single-acquisition single-photon emission computed tomographic (SPECT) protocol using a multihead SPECT camera equipped with an ultra-high energy collimator to evaluate rest metabolism/stress perfusion simultaneously with fluorine-18 (F-18) deoxyglucose/technetium-99m (Tc-99m) 2-hexakis-2-methoxy-2-methylpropyl isonitrile (MIBI). BACKGROUND: The most accurate and logistic method of identifying injured but viable myocardium remains a diagnostic challenge. METHODS: Sixty-five patients were given 25 to 50 g of glucose and, after approximately 60 min, an injection of 370 MBq (10 mCi) of F-18 fluorodeoxyglucose. After a 35-min distribution phase, patients underwent exercise or pharmacologic stress followed by administration of 925 MBq (25 mCi) of Tc-99m MIBI. Five patients underwent F-18 fluorodeoxyglucose position emission tomography before dual-isotope SPECT: RESULTS: With a window of 20% for both photopeaks and a technetium-99m/fluorine-18 concentration of 3.2:1, the "spillover" from fluorine-18 into the technetium-99m window is < 6% of the total counts in the window in patients with a normal distribution of both radiopharmaceuticals. Phantom images clearly demonstrated cardiac defects measuring 2 x 1 and 2 x 0.5 cm. There was no significant difference in the images of the five patients who underwent both positron emission tomography and SPECT: Fifty-seven patients (mean [+/- SD] age 55 +/- 15 years, range 25 to 83; 38 men, 19 women) had satisfactory images and were included in the study. Twenty-one patients had normal study results; 15 had mismatched defects; 14 had matched defects; and 7 had both matched and mismatched defects. Twenty-three patients (mean age 54 +/- 6 years, range 30 to 83; 14 men, 9 women) underwent coronary angiography within 3 months of dual-isotope SPECT: There were seven normal studies, eight with mismatched defects, one with a matched defect and seven with matched and mismatched defects. When stenosis > 70% was used as the criterion for a diagnosis of coronary artery disease, dual-isotope SPECT had a sensitivity of 100%, specificity of 88%, positive predictive value of 93%, negative predictive value of 100% and an accuracy of 96%. CONCLUSIONS: Dual-isotope SPECT may provide an alternative, accurate, cost-effective method to nitrogen-13 ammonia/F-18 fluorodeoxyglucose positron emission tomography or thallium-201 reinjection for identifying injured or dysfunctional but viable myocardium.

Coronary Angiography↗

PubMed1995

Optimal cutoff levels of F-18 fluorodeoxyglucose uptake in the differentiation of low-grade from high-grade brain tumors with PET.

PURPOSE: To determine the optimal cutoff level of fluorine-18-labeled fluorodeoxyglucose (FDG) uptake in the differentiation of low-grade from high-grade cerebral tumors at position emission tomography (PET). MATERIALS AND METHODS: The authors retrospectively reviewed images from PET, magnetic resonance imaging, and computed tomography performed in 58 consecutive patients with histologically proved brain tumors. There were 32 high-grade tumors (20 gliomas) and 26 low-grade tumors (18 gliomas). RESULTS: The best cutoff level of FDG uptake ratios in the differentiation of high-grade from low-grade tumors was 1.5 for tumor-to-white matter (T/WM) ratios and 0.6 for tumor-to-cortex (T/C) ratios. These levels were the same when only gliomas were analyzed and when all tumors were analyzed. When a T/WM ratio of more than 1.5 was considered indicative of a high-grade tumor, the sensitivity and specificity were 94% and 77%, respectively. The results were similar for the T/C ratio. CONCLUSION: Cutoff levels of 1.5 for the T/WM FDG uptake ratio and 0.6 for the T/C ratio are useful in the differentiation of low-grade from high-grade gliomas with PET.

Adult↗

PubMed1995

Rest myocardial perfusion/metabolism imaging using simultaneous dual-isotope acquisition SPECT with technetium-99m-MIBI/fluorine-18-FDG.

UNLABELLED: The purpose of this study was to develop a dual-isotope simultaneous acquisition (DISA) protocol using a multihead SPECT camera equipped with an ultrahigh-energy (UHE) collimator to evaluate simultaneously rest cardiac perfusion and metabolism with 99mTc-MIBI/18FDG. METHODS: Physical measurements were first performed with phantoms to develop the acquisition protocol. Fifteen patients underwent DISA-SPECT with 99mTc-MIBI/18FDG to validate the protocol. To evaluate the quality of the 99mTc-MIBI images acquired with the UHE collimator, four patients underwent a resting 99mTc-MIBI scan acquired with a high-resolution, low-energy collimator prior to DISA-SPECT. RESULTS: With a window of 20% for both photopeaks and a 99mTc/18F concentration ratio of 3.2:1, the spillover from 18F into the 99mTc window is 6% of the counts in the window for normal subjects. Phantom images clearly demonstrated defects measuring 2 x 1 and 2 x 0.5 cm. Technetium-99m-MIBI images obtained with the UHE and high-resolution collimators provided similar diagnostic information. Using a stenosis of > 70% as criteria to diagnose coronary artery disease, DISA-SPECT had a sensitivity of 100% and a positive predictive value of 93%. CONCLUSION: Simultaneous evaluation of rest myocardial perfusion/metabolism with a multihead SPECT camera equipped with an UHE collimator is possible using 99mTc-MIBI/18FDG with a dual-isotope simultaneous acquisition protocol.

Deoxyglucose↗

PubMed1995

Nitrogen-13-ammonia and PET to detect allograft coronary artery disease after heart transplantation: comparison with coronary angiography.

UNLABELLED: The diffuse nature of allograft coronary artery disease (CAD) suggests that global myocardial blood flow (MBF) may decrease with time after transplantation; therefore the diagnosis of this disease remains problematic. METHODS: To investigate whether PET detects a fall in allograft MBF over time, PET scans (108) were obtained from 43 heart transplant recipients. Thirty-five patients underwent two serial PET scans 1 yr apart. MBF was measured by PET using 13N-ammonia as a tracer. Coronary angiography was performed parallel with PET imaging and compared with perfusion rates measured by PET scans. RESULTS: MBF measured by PET decreased sequentially with time. The mean MBF was 73 +/- 21, 56 +/- 13, 51 +/- 11 and 51 +/- 27 ml/min/100 g of tissue in patients surviving 3 mo, 1, 2 and 3 yr after transplantation, respectively. Significant MBF decrease occurred within 1 yr after transplantation. Sequential PET studies showed a decrease in MBF in 22 of 35 patients (63%). Mean MBF for the first and second scans was 65 +/- 18 and 54 +/- 16, respectively. MBF decrease was more profound in patients (n = 11) angiographic evidence of CAD. There was a trend towards increased rejection and CMV infection rates in patients with decreased MBF. CONCLUSION: With time, PET detects a decrease in MBF in cardiac allografts. The frequency of MBF decrease detected by PET is concordant with the true incidence of allograft CAD, suggesting that sequential PET is a more sensitive modality for monitoring allograft CAD than angiography.

Ammonia↗

PubMed1995

FDG-SPECT: correlation with FDG-PET.

UNLABELLED: The clinical utility of FDG-PET imaging in the evaluation of patients with cardiac, oncologic and neurologic diseases is well documented. The major disadvantages of PET continue to be its high cost and limited availability. METHODS: With the goal of providing equivalent diagnostic information using a widely available, less expensive modality, we evaluated the clinical utility of FDG-SPECT imaging with a conventional dual-headed camera as compared to PET in 21 patients. RESULTS: To compare the image quality of the two modalities, major physical parameters and phantom determinations were obtained. By using the 511-keV collimators, we achieved resolution and system volume sensitivity that were less than those for PET by factors of 2.6 and 8, respectively. The SPECT system, on the other hand, could easily resolve 2 x 0.5-cm cold defects in the heart phantom and 2-cm hot lesions in a 22-cm cylindrical phantom with a target-to-background ratio of 5:1. FDG-SPECT imaging of nine patients with heart disease yielded similar diagnostic information of the amount of viable myocardium present when compared to PET. In seven of eight patients, malignant tissue visualized with FDG-PET was seen equally well with SPECT. The lesions not visualized with FDG-SPECT were either small (< or = 1.5 cm) or benign. SPECT imaging of four patients with cerebral lesions was inconclusive due to the small sample size but seemed promising. CONCLUSION: FDG-SPECT with 511-keV collimation is less expensive, more available and technically simpler than PET. We believe that FDG-SPECT has achieved sufficient sensitivity and resolution to detect myocardial viability and diagnose malignant tumors > or = 2 cm in diameter.

Adult↗

PubMed1994

Magnetic resonance imaging of Carney's triad.

Carney's triad, a rare disorder affecting young females, is characterized by the presence of at least two of the three following neoplasms: gastric epithelioid leiomyosarcoma, extra-adrenal paraganglioma, and pulmonary chondroma. Diagnosis and follow-up evaluation of cases of Carney's triad may require an approach that uses a combination of modalities, including magnetic resonance imaging (MRI), metaiodobenzyl-guanidine (MIBG) I 131 scintigraphy, and computed tomography. MRI is as effective as MIBG scintigraphy in detecting functioning paragangliomas. In the evaluation of suspected cases of Carney's triad in which there is clinical and biochemical evidence of a paraganglioma, MRI is the modality of choice for screening and follow-up. We report a case of gastric leiomyosarcoma and extra-adrenal paraganglioma in a young woman whose initial presentation was at 7 years of age. To our knowledge, this is the earliest presentation of this disorder.

Adult↗

PubMed1993

Carcinoma in a transplanted kidney detected with MAG3 scintigraphy.

We report on two cases of infiltrative renal tumor developing in two kidney transplant recipients from a single cadaveric donor source. Interestingly, while this is only the second case of a de novo renal allograft tumor, both were morphologically infiltrative. The fact that both tumors were infiltrative may be secondary to immunosuppression therapy. While computed tomography (CT) evaluation of suspected renal pathology provides excellent anatomical detail, renal transplant recipients are initially evaluated using ultrasound and renal scintigraphy to avoid contrast reagents which could further impair renal function, as well as to reduce the image procedure cost and the patient radiation dose. Unfortunately, infiltrative tumors may be isoechoic on ultrasound, providing a confusing or conflicting report when compared to scintigraphic findings. This case report is significant radiographically because the original neoplasm was initially detected using technetium-99m-labeled mercaptoacetyltriglycine (99mTc-MAG3) scintigraphy and was not appreciated by sonographic studies, even retrospectively. This case demonstrates the usefulness of 99mTc-MAG3 scintigraphy to follow-up evaluations of renal transplants by providing detailed anatomical information as well as functional analysis of the kidney.

Adult↗