Attenuation-Corrected vs. Nonattenuation-Corrected 2-Deoxy-2-[F-18]fluoro-d-glucose-Positron Emission Tomography in Oncology, A Systematic Review

Purpose: To perform a systematic review and meta-analysis to determine the diagnostic accuracy of attenuation-corrected (AC) vs. nonattenuation-corrected (NAC) 2-deoxy-2-[F-18] fluoro-D-glucose-positron emission tomography (FDG-PET) in oncological patients. Procedures: Following a comprehensive search of the literature, two reviewers independently assessed the methodological quality of eligible studies. The diagnostic value of AC was studied through its sensitivity/specificity compared to histology, and by comparing the relative lesion detection rate reported with NAC-PET vs. AC, for full-ring and dual-head coincidence PET (FRand DH-PET, respectively). Results: Twelve studies were included. For FR-PET, the pooled sensitivity/specificity on a patient basis was 64/97 % for AC and 62/99 % for NAC, respectively. Pooled lesion detection with NAC vs. AC was 98 % [95 % confidence interval (95 % CI): 96Y99%, n=1,012 lesions] for FR-PET, and 88 % (95 % CI:81Y94%, n=288 lesions) for DH-PET. Conclusions: Findings suggest similar sensitivity/specificity and lesion detection for NAC vs. AC FR-PET and significantly higher lesion detection for NAC vs. AC DH-PET

Bone metabolic activity in hyperostosis cranialis interna measured with 18F-fluoride PET

F-18-Fluoride PET/CT is a relatively undervalued diagnostic test to measure bone metabolism in bone diseases. Hyperostosis cranialis interna (HCI) is a (hereditary) bone disease characterised by endosteal hyperostosis and osteosclerosis of the skull and the skull base. Bone overgrowth causes entrapment and dysfunction of several cranial nerves. The aim of this study is to compare standardised uptake values (SUVs) at different sites in order to quantify bone metabolism in the affected anatomical regions in HCI patients. Nine affected family members, seven non-affected family members and nine non-HCI non-family members underwent F-18-fluoride PET/CT scans. SUVs were systematically measured in the different regions of interest: frontal bone, sphenoid bone, petrous bone and clivus. Moreover, the average F-18-fluoride uptake in the entire skull was measured by assessing the uptake in axial slides. Visual assessment of the PET scans of affected individuals was performed to discover the process of disturbed bone metabolism in HCI. F-18-Fluoride uptake is statistically significantly higher in the sphenoid bone and clivus regions of affected family members. Visual assessment of the scans of HCI patients is relevant in detecting disease severity and the pattern of disturbed bone metabolism throughout life. F-18-Fluoride PET/CT is useful in quantifying the metabolic activity in HCI and provides information about the process of disturbed bone metabolism in this specific disorder. Limitations are a narrow window between normal and pathological activity and the influence of age. This study emphasises that F-18-fluoride PET/CT may also be a promising diagnostic tool for other metabolic bone disorders, even those with an indolent course

Blocking the Saphenofemoral Junction During Ultrasound-Guided Foam Sclerotherapy - Assessment of a Presumed Safety-measure Procedure

AbstractObjectivesUltrasound-guided foam sclerotherapy (UGFS) is a technique in which a mixture of sclerosing drug and gas is used to treat varicose veins. Several authors have demonstrated transient systemic effects after UGFS. These effects are not well understood but probably originate from a systemic distribution of the sclerosing foam. Therefore, safety measures have been developed to prevent foam from flowing into the deep venous system. The aim of the study is to evaluate whether blockage of the saphenofemoral (SF) junction by either manual compression or surgical ligation prevents microbubbles from leaking into the deep venous circulation.MethodsTo detect the distribution of microbubbles, radioactive pertechnetate (99mTcO4−) was added to the foam solution. Initially, in vitro trials were performed in the laboratory to investigate the effect of 99mTc on foam stability. The time taken for foam to liquefy was measured for foam alone and for the mixture with 99mTc. In subsequent research, eight varicose great saphenous veins (GSVs) were treated by UGFS. In three patients, this treatment was preceded by surgical ligation of the SF junction. In three patients, the groin was manually compressed during UGFS. In two patients, UGFS was performed without compression of the groin.ResultsIn vitro, 99mTc did not influence foam stability; after 2.6 min all foam had reduced to liquid, regardless of whether 99mTc had been added or not. In vivo trials showed that all patients showed a decrease in the cumulative amount of 99mTc detected in the GSV following polidocanol-99mTc mixture injection. However, the decrease of radioactivity was slightly reduced when compression or ligation of the SF junction was performed.ConclusionsBlocking the SF junction during UGFS using either manual compression or ligation does not prevent, but may reduce the flow of foam into the femoral vein

Early response monitoring in malignant lymphoma using fluorine-18 fluorodeoxyglucose single-photon emission tomography

Metabolic response monitoring early during chemotherapy may have a major impact on clinical management of patients with malignant lymphoma. In two patients with non-Hodgkin's lymphoma fluorine-18 fluorodeoxyglucose (IgFDG) single-photon emission tomography (SPET) studies were performed during the first two chemotherapeutic cycles. Persisting uptake predicted treatment failure whereas a sharp reduction of 18FDG uptake was demonstrated in the case of a responsive tumour. Qualitative analysis of conventional 18FDG imaging may thus serve to identify patients with a non-responding tumour. The potential of this technique in the determination of the initial response remains to be established. Imaging with 18FDG and SPET appears promising as a more easily available methodology than 18FDG positron emission tomography

The performance of 18F-fluorodeoxyglucose positron emission tomography in small solitary pulmonary nodules

Solitary pulmonary nodule (SPN, intraparenchymal lung mass <3 cm) is often a diagnostic challenge. This study was performed to evaluate the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography (FDG PET) in radiologically indeterminate SPN ≤10 mm on spiral CT. Between August 1997 and March 2001, we identified all patients with radiologically indeterminate SPNs ≤10 mm who were referred for FDG PET imaging at the VU University Medical Centre. All PET scans were retrospectively reviewed by an experienced nuclear medicine physician. PET was considered positive in cases with at least moderately enhanced focal uptake, and otherwise as negative. Lesions were considered benign on the basis of histology, no growth during 1.5 years or disappearance within at least 6 months. Thirty-five patients with 36 SPNs ≤10 mm in diameter at clinical presentation were identified (one patient had two metachronous lesions). In 13 of 14 malignant nodules and in two of 22 benign nodules, diagnosis was confirmed by histology. Prevalence of malignancy was 39%. PET imaging correctly identified 30 of 36 small lesions. One lesion proved to be false negative on PET (CT: 10 mm), and in five lesions, PET scans proved to be false positive. Specificity was 77% (17/22; 95% CI: 0.55-0.92), sensitivity 93% (13/14; 95% CI: 0.66-1.0), positive predictive value 72% (13/18; 95% CI: 0.46-0.90) and negative predictive value 94% (17/18; 95% CI: 0.73-1.0). This retrospective study suggests that FDG PET imaging could be a useful tool in differentiating benign from malignant SPNs ≤10 mm in diameter at clinical presentation. Such results may help in the design of larger prospective trials with structured clinical work-up

How to use a gestalt interpretation for ventilation-perfusion lung scintigraphy

The use of a so-called gestalt interpretation, an integration of different sets of criteria and the physician's own experience, has been advocated in the interpretation of lung scintigraphs of patients with clinically suspected pulmonary embolism. However, data on the reliability of this approach are limited. The aim of this study was to investigate the observer variability and accuracy of the gestalt interpretation of perfusion scintigraphy (combined with chest radiography) as well as the impact of adding ventilation scintigraphy and clinical pretest information. Methods: Three experienced observers independently reviewed the chest radiograph and ventilation-perfusion scans of 101 consecutive patients with clinically suspected pulmonary embolism. All datasets were reviewed twice by each observer, using a visual analog scale to indicate the estimated probability of pulmonary embolism. The results of the gestalt interpretations were analyzed against the presence or absence of pulmonary embolism. Results: All 3 gestalt interpretations had a good-to-excellent interobserver variability (intraclass correlation coefficient [ICC], 0.73-0.89), with similar intraobserver agreement (ICC, 0.76-0.95). The performance of all 3 readers was comparable. The areas under the curve (AUCs) of all 3 observers were high and similar (for observer 1, the AUCs were 0.96 [95% confidence interval (CI)], 0.93-1.00), 0.96 (95% CI, 0.93-1.00), and 0.95 (95% CI, 0.90-1.00), respectively, for the 3 gestalt interpretations). Conclusion: A gestalt interpretation is a useful classification scheme with good-to-excellent intra- and interobserver variability. However, the interpretation and the consequences of this result are dependent on the observer. Unexpectedly, the addition of information on ventilation scintigraphy and clinical information did not affect the overall assessment

Impact of lymphoscintigraphy on sentinel node identification with technetium-99m-colloidal albumin in breast cancer

Identification of the sentinel node by using colloidal tracers and a gamma probe or lymphoscintigraphy could be an effective alternative for the complicated original dye-oriented approach. We studied the sentinel node detection rate using early and delayed imaging in breast cancer patients. Methods: Thirty-seven patients were imaged 2 hr and 18 hr after peritumoral injection of 99mTc-colloidal albumin. Preoperatively, axillary loci were located with a handheld gamma probe that was also used to isolate radiolabeled nodes from the axillary dissection specimens. The predictive value of the sentinel node for the axillary tumorstatus was evaluated with histological examination. Results: Two and 18 hr after injection, lymphoscintigraphy revealed one to three separate axillary lymph nodes in 33 and 34 patients, respectively. In 30 patients the axillary foci were easily localized with the gamma probe preoperatively. In all 34 patients (92%), with visualized axillary foci, at least one radioactive sample could be retrieved using the gamma probe (total 53 samples). Metastases were found in the sentinel nodes of 11 patients, in seven of 11 being the only tumor-positive lymph node in the axilla. There were no false-negative sentinel nodes. Conclusion: The selective targeting and prolonged intranodal retention of 99mTC-colloidal albumin allows successful sentinel node identification in most (92%) patients

Predictive value of planar 18F-fluorodeoxyglucose imaging for cardiac events in patients after acute myocardial infarction

This long-term study examines the predictive value of planar myocardial 18F-fluorodeoxyglucose (FDG) imaging far cardiac events after acute myocardial infarction (AMI). From December 1989 to April 1991, 59 consecutive patients with AMI had undergone planar rest thallium-201 (TI-201)/FDG imaging far viability assessment; 53 (42 men) were included in this study. Mean fallow-up was 47 ± 15 months. Cardiac events were defined as cardiac- related death, reinfarction, late revascularization, and unstable angina pectoris. A mismatch pattern was defined as a FDG uptake exceeding TI-201 uptake by ≤20%. A concordant reduction in flow and metabolism was defined as a match. In the mismatch group (n = 39) were 19 events versus 1 event in the match group (n = 14) (p <0.009). In the mismatch group were 5 cardiac deaths, 3 reinfarctions, 7 late revascularizations, and 4 patients had unstable angina pectoris. There was 1 cardiac death in the match group. The event- free rote estimated using Kaplan Meier curves for patients with and without a mismatch was significantly different (p = 0.018). The relative risk for patients with a mismatch far developing a future cardiac event was estimated at 7.8 versus patients with a match. Thus, planar myocardial FDG imaging shortly after AMI has important prognostic significance far prediction of future cardiac events. Patients with a mismatch shortly after AMI have a high risk for future cardiac events on medical therapy