肺部单发结节在~(18)氟脱氧葡萄糖-正电子发射体层显像检查后外科决策

目的探讨肺部单发结节(SPN)患者在18氟脱氧葡萄糖-正电子发射体层显像(FDG-PET)检查后的外科决策。方法 1998年10月—2006年4月对375例直径1.0～3.0 cm的SPN患者行FDG-PET检查,采用目测法结合半定量分析判读。结果 FDG-PET定性诊断的敏感度、特异度、准确率分别为73.7%(188/255)、71.7%(86/120)、73.1%(274/375);FDG-PET无法区别良性显影病变与腺癌;对于肺外病灶FDG-PET也存在假阳性。结论 PET检查阳性的SPN,除非抗感染或抗结核治疗有效,否则都应当通过手术切除等途径确诊;对PET检查阴性的SPN患者,或手术切除,或定期随访。     

Carbon-11 choline positron emission tomography in musculoskeletal tumors: comparison with fluorine-18 fluorodeoxyglucose positron emission tomography

PURPOSE: Recently, a new positron emission tomography (PET) tracer, carbon-11 choline, has been introduced in oncology investigations, but the role of choline PET in musculoskeletal tumor evaluation has not been previously examined. This is the first trial to investigate the utility of choline PET in evaluating musculoskeletal tumors in comparison with fluorine-18 fluoro-2-deoxy-D-glucose (FDG) PET. METHOD: Thirty-three patients were examined with both choline PET and FDG PET, of which standardized uptake values (SUVs) were used for evaluation of the lesions. To decide the appropriate cutoff value and compare the two PET studies, receiver operating characteristic curve analysis was used. The binomial test was used for comparison of sensitivities between choline PET and FDG PET. RESULTS: A significant correlation (r = 0.537, P = 0.0013) between choline and FDG SUVs was noted for all lesions (n = 33). Mean SUVs for malignant tumors were significantly higher than those for benign lesions in both choline PET and FDG PET. Using a cutoff value of 2.7 for choline SUVs, the sensitivity for correctly diagnosing malignancy was 92.3% (12/13) with a specificity of 90.0% (18/20), resulting in an accuracy rate of 90.9%. With use of a cutoff value of 3.3 for SUVs in FDG PET, the sensitivity was 84.6% (11/13) with a specificity of 80.0% (16/20), resulting in an accuracy rate of 81.8%. The receiver operating characteristic curves of two analyses showed that the mean area under the curve value of choline PET (0.9577 +/- 0.041) was significantly greater (P = 0.0488) than that of FDG PET (0.8192 +/- 0.0806). There was no significant difference in sensitivity and specificity between choline PET and FDG PET analysis using either the binomial test (P = 0.4531) or McNemar test (P = 0.371). CONCLUSION: Choline PET analysis may not be inferior to FDG PET analysis for differentiating malignant from benign musculoskeletal tumors. The advantages of choline PET were shorter examination time and little retention in the bladder; therefore, this modality may be useful for preoperative planning for musculoskeletal tumors, especially for lesions around the hip joints.     

Significance of fill-in after thallium-201 reinjection following delayed imaging: comparison with regional wall motion and angiographic findings

To identify reversible defects, reinjection of a small amount of thallium-201 (201Tl) following 3-hr delayed imaging was performed in 60 patients with coronary artery disease who had perfusion abnormalities on their post-exercise 201Tl images. Thallium-201 uptake was visually scored and judged as normal (Group 1), reversible defect (Group II), new fill-in after reinjection (Group IIIa) and no fill-in even after reinjection (Group IIIb). New fill-in after reinjection was observed in 27 segments of the 85 segments (32%), showing persistent defect on the stress and delayed images. The wall motion in Group IIIa was worse than Group II but better than Group IIIb. Group IIIa showed Q-wave on ECG more often (69%) than Group II (27%) (p less than 0.01), but less often than Group IIIb (85%) (p less than 0.05). These data indicate that the reinjection 201Tl imaging often identifies new fill-in in the areas of no redistribution on the delayed images and it may hold promise for assessing tissue viability which the conventional imaging may underestimate.     

The role of positron emission tomography with fluorine-18-deoxyglucose in identifying colorectal cancer metastases to liver

Liver metastasis is a common consequence of colorectal carcinoma. Early and accurate detection of liver metastasis is crucial for a decision about partial hepatectomy, which is considered a standard and potentially curative therapy in such a setting. The presence of extrahepatic metastases will exclude surgical resection as a therapeutic option. Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) has been successful in detecting and staging a variety of malignancies. The purpose of this study was to assess the utility of FDG-PET in the accurate detection of liver and distal metastases from colorectal cancer. The results of 80 PET and computed tomography (CT) scans were compared with surgical pathology and clinical outcome. FDG-PET detected liver metastases in 28 patients, with a sensitivity of 100%. CT detected metastasis in 20 patients, giving a sensitivity of 71.4%. In addition, in one patient with negative CT findings, PET detected a focus of hypermetabolism in the region adjacent to liver, which was proven to be a second focus of primary colon carcinoma. In six patients with liver metastases, PET correctly detected extrahepatic lesions, while CT only detected hepatic lesions. In conclusion, FDG-PET is an excellent imaging modality for the detection and staging of liver metastases in patients with colorectal carcinomas.     

Oncological applications of positron emission tomography with fluorine-18 fluorodeoxyglucose

Positron emission tomography (PET) is now primarily used in oncological indication owing to the successful application of fluorine-18 fluorodeoxyglucose (FDG) in an increasing number of clinical indications at different stages of diagnosis, and for staging and follow-up. This review first considers the biological characteristics of FDG and then discusses methodological considerations regarding its use. Clinical indications are considered, and the results achieved in respect of various organs and tumour types are reviewed in depth. The review concludes with a brief consideration of the ways in which clinical PET might be improved.     

Roles of positron emission tomography with fluorine-18-deoxyglucose in the detection of local recurrent and distant metastatic sarcoma

Sarcomas are a heterogeneous group of tumors comprising approximately 1% of all malignancies. Definitive treatment of sarcoma is surgical resection. However, after surgical removal, 40% to 60% of the patients will develop local or distant recurrence. Therefore, the early detection and treatment of recurrence is an important part of modern sarcoma therapy. Positron emission tomography with fluorine-18-deoxyglucose (FDG-PET) has been highly successful in detecting and staging a variety of malignancies. However, its use in the management of patients with sarcoma is less defined. The purpose of our study was to assess the potential roles of FDG-PET in the detection of local recurrence and distant metastases. In this retrospective study, the images of 33 FDG-PET scans, reports of 29 computed tomography (CT) scans, and 8 magnetic resonance imaging (MRI) scans from 28 patients were compared with surgical pathology or clinical follow up for at least 6 months. FDG-PET detected all 25 cases of local and distant recurrences with 100% sensitivity. CT was able to detect 18 of the 22 possible cases of recurrent disease, whereas MRI was able to detect 5 of 7 cases of recurrent disease. PET was particularly useful in patients with extensive histories of surgery and radiation therapy, precisely the setting in which CT and MRI have the lowest specificity and sensitivity. In conclusion, FDG-PET was a sensitive test to detect local and distant recurrences of sarcoma and this warrants further investigation.     

Positron emission tomography using fluorine-18-fluorodeoxyglucose in malignant lymphoma: a comparison with proliferative activity.

To evaluate the relationship between PET using 18F-fluorodeoxyglucose (FDG) and pathological findings and to compare indices obtained by FDG-PET, FDG-PET was performed in 23 patients with untreated malignant lymphoma. Three indices obtained by FDG-PET, tumor-to-normal contrast ratio (TCR), distribution absorption ratio (DAR), k1k2/(k2 + k3), correlated with proliferative activity which was pathologically estimated both by mitotic count and by proportion of cells in all phases of the cell cycle. The relationship did not significantly change according to which of the three indices was chosen. FDG-PET, which shows the proliferative activity of tumors, is considered to be a useful method for managing tumors.     

Sclerosing mediastinitis: findings on fluorine-18 fluorodeoxyglucose positron emission tomography

Whole-body serial positron emission tomography scanning was done using fluorine-18 fluorodeoxyglucose (F-18 FDG) in a patient with a mediastinal mass. Uptake correlated well with the clinical symptoms and aggressiveness of the disease. Based on the F-18 FDG findings, a biopsy specimen was taken from the active region of the mass, which confirmed the diagnosis of sclerosing mediastinitis.     

Assessment of malignancy of glioma by positron emission tomography with 18F-fluorodeoxyglucose and single photon emission computed tomography with thallium-201 chloride

The histological diagnosis and proliferative potential measured by bromodeoxyuridine (BrdU) labelling index (LI) were corelated with preoperative CT and contrast-enhanced, MRI, ¹⁸F-flurodeoxyglucose positron emission tomography (PET) and ²⁰¹T1 single photon emission computed tomography (SPECT) in 43 patients with various grades of glioma. ²⁰¹T1 SPECT had slightly higher sensitivity to tumours with BrdU LI N 5 % (showing 10/10) than ¹⁸F-FDG PET (7/8 tumours). ¹⁸F-FDG PET was better for identifying tumours of BrdU LI < 1 % (13/15) than ²⁰¹T1 SPECT (13/22). Accumulation of ²⁰¹T1 in the tumour was slightly different from contrast enhancement on CT and/or MRI, and gave “false-postive” results in some low-grade gliomas. However, ²⁰¹T1 SPECT, which is available in many hospitals and may cost less, provided useful information to supplement that from CT and MRI. Received: 25 November 1996 Accepted: 8 September 1997     

Role of positron emission tomography using fluorine-18 fluoro-2-deoxyglucose in predicting improvement in left ventricular function in patients with idiopathic dilated cardiomyopathy

Improvement in left ventricular (LV) function in patients with idiopathic dilated cardiomyopathy (DCM) by medical treatment has been suggested. Thus, it is important to evaluate which patients will respond to medical therapy. Positron emission tomography (PET) with fluorine-18 fluoro-2-deoxyglucose (FDG) and cardiac catheterization were performed in 20 patients with DCM before the initiation of medical therapy. The regional myocardial glucose utilization rate (rMGU) was measured with FDG PET. Subjects were divided into two groups, group 1 (event-free patients, n=10) and group 2 (clinical cardiac events, n=10). Haemodynamic and PET parameters before the initiation of medication were compared between the two groups and between patients with and patients without improvement in LV function. Ejection fraction (EF) was significantly higher in group 1 (35.8%±9.0%) than in group 2 (24.8%±7.0%) and LV end-diastolic pressure (LVEDP) was significantly lower in group 1 (8.4±1.7 mmHg) than in group 2 (11.6±3.5 mmHg). Average rMGU (mg min^–1 100 g^–1) was similar in group 1 (11.2±2.5 mg min^–1 100 g^–1) and group 2 (11.2±2.9 mg min^–1 100 g^–1), while %CV of rMGU was significantly lower in group 1 (11.1%±6.3%) than in group 2 (29.9%±13.9%, P<0.01). Furthermore, LV function normalized in seven patients in group 1. In these seven patients, EF (35.1%±10.9%), LVEDP (8.2±2.0 mmHg) and average rMGU (11.8±2.7 mg min^–1 100 g^–1) were comparable with those in patients without LV functional improvement (EF: 31.6%±9.1%; LVEDP: 10.7±3.3 mmHg; average rMGU: 10.8± 2.7 mg min^–1 100 g^–1). However,% CV of rMGU in patients with LV functional improvement (9.6%±5.6%) was significantly lower than in those without such improvement (26.3%±14.1%, P<0.01). %CV of rMGU <13.6% predicted prognosis with a sensitivity of 80%, a specificity of 100% and an accuracy of 90%. %CV of rMGU <13.6% also predicted improvement in LV function, with a sensitivity of 75%, a specificity of 92% and an accuracy of 85%. However, EF failed to predict improvement of LV function. In is concluded that homogeneous myocardial glucose utilization rate can predict both prognosis and improvement in LV function achieved by medical therapy in patients with DCM. Received 9 December 1997 and in revised form 11 March 1998     

Value and limitation of stress thallium-201 single photon emission computed tomography: comparison with nitrogen-13 ammonia positron tomography

The diagnostic value of exercise 201Tl single photon emission computed tomography (SPECT) for assessing coronary artery disease (CAD) was comparatively evaluated with exercise [13N] ammonia positron emission tomography (PET). Fifty-one patients underwent both stress-delayed SPECT imaging using a rotational gamma camera and stress-rest PET imaging using a high resolution PET camera. Of 48 CAD patients, SPECT showed abnormal perfusion in 46 patients (96%), while PET detected perfusion abnormalities in 47 (98%). The sensitivity for detecting disease in individual coronary arteries (greater than 50% stenosis) was also similar for SPECT (81%) and PET (88%). When their interpretations were classified as normal, transient defect, and fixed defect in 765 myocardial segments, SPECT and PET findings were concordant in 606 segments (79%). However, 66 segments showed a fixed defect by SPECT but a transient defect by PET, whereas there were only nine segments showing a transient defect by SPECT and a fixed defect by PET. PET identified transient defects in 34% of the myocardial segments showing a fixed defect by SPECT. We conclude that both stress SPECT and PET showed high and similar sensitivities for detecting CAD and individual stenosed vessels. Since stress-delayed SPECT with single tracer injection detected fewer transient defects, it may underestimate the presence of myocardial ischemia, compared with high resolution PET imaging with two tracer injections.     

Evaluation of pancreatic islet cell tumors by fluorine-18 fluorodeoxyglucose positron emission tomography: comparison with other modalities

PURPOSE: Pancreatic islet cell tumors are potentially malignant tumors and are often difficult to detect with current imaging modalities. Positron emission tomography (PET) using fluorine-18-labeled fluorodeoxyglucose (FDG) is an imaging technique with high sensitivity for malignant tumors. The aim of this study was to assess the feasibility of FDG PET to detect pancreatic islet cell tumors. METHODS: Nineteen lesions of histologically proved islet cell tumors were evaluated in 12 patients (5 men, 7 women; ages 22 to 77 years). FDG uptake was analyzed semiquantitatively as a standardized uptake value. The diagnostic accuracy of PET was compared with that of US, CT, and MRI. RESULTS: Of 19 lesions, 8 showed positive PET results (standardized uptake value > 2.3), and localization was indicated in 2 lesions. In nine tumors that were not detected by PET, seven were small tumors ranging from 1.5 to 8 mm in diameter and were not identified by other imaging methods. The sensitivity rate of PET was 53%, whereas those of US, CT, and MRI were 53%, 50%, and 53%, respectively. CONCLUSION: Our data suggest that FDG PET has a limitation in that it does not detect some small-sized islet cell tumors, mainly depending on their size, but it has potential utility as a complementary modality for other imaging techniques.     

Assessment of response to cancer therapy using fluorine-18-fluorodeoxyglucose and positron emission tomography

In order to evaluate the usefulness of 18F-FDG PET in the assessment of therapeutic effects, FDG-PET studies were performed both before and after therapy in 26 patients with miscellaneous malignant tumors. The change in FDG uptake by therapy was compared with the change in tumor size and prognosis. All 26 lesions had a high FDG uptake before therapy. Five of seven lesions which had a relatively low FDG uptake before therapy showed no change or increase in tumor size by therapy. The decreased FDG uptake after therapy was more prominent in the partial response group than in the no change group. FDG uptake before therapy in the non-relapse group was higher than that in the relapse group. However, a decreased FDG uptake did not necessarily indicate a good prognosis. One patient with no change in tumor size and a decreased FDG uptake had no recurrence. This suggests that FDG-PET has a complementary role in the assessment of therapeutic effects.     

Noninvasive detection of hypoxic myocardium using fluorine-18-fluoromisonidazole and positron emission tomography.

Fluoromisonidazole (FMISO) is metabolically trapped in viable cells as a function of reduced cellular pO2. Therefore [18F]-FMISO is potentially useful for evaluating patients with hypoxic but viable myocardium. The goal of this study was to investigate [18F]FMISO uptake in ischemic myocardium non-invasively using positron emission tomography (PET). Studies were performed in 10 open-chest dogs subjected to either complete (Group 1, n = 5) or partial (Group 2, n = 5) occlusion of the left anterior descending coronary artery. The tracer was administered by intravenous bolus following the onset of ischemia and serial PET images were acquired for the next 4 hr. In Group 1, viability was assessed using histochemical staining (nitroblue tetrazolium, NBT) and 99mTc-pyrophosphate (Tc-PYP). In Group 2, viability was assessed using measurements of regional wall motion, histochemical staining and histology (two animals). In each study, PET images obtained at times between 2 and 4 hr postinjection showed specific enhancement of tracer activity in the distal anterior wall and apex of the left ventricle. At 4 hr, the tissue-to-blood pool count ratio was significantly higher in ischemic regions; 1.8 +/- 0.4 for Group 1 and 1.6 +/- 0.2 for Group 2 versus 1.0 +/- 0.1 in nonischemic regions. Postmortem tissue sampling of Group 1 hearts showed significant FMISO retention in samples without evidence for infarction, either by NBT or Tc-PYP deposition, as well as in more severely ischemic regions. In Group 2 animals, FMISO was retained in myocardial regions with reduced blood flow (microspheres), which exhibited improved contraction following reperfusion. We conclude that PET imaging of [18F]FMISO is a promising technique for the noninvasive identification of viable hypoxic myocardium.     

Relation between myocardial uptake of thallium-201 chloride and fluorine-18 fluorodeoxyglucose imaged with single-photon emission tomography in normal individuals

Recently, we have demonstrated the feasibility of imaging myocardial uptake of fluorine-18 fluorodeoxyglucose (FDG) with single-photon emission tomography (SPET) using a specially designed collimator. Thallium-201 was used to determine distribution of perfusion for comparison with FDG uptake. However, regional²⁰¹Tl and FDG activities may be different, based on differences in tracer attenuation and the use of different collimators. To study the relation between tracer activities imaged with SPET, nine healthy individuals underwent resting²⁰¹Tl SPET and FDG SPET during a hyperinsulinaemic euglycaemic clamp. The SPET data were analysed semiquantitatively, using circumferential profiles. Mean profiles of midventricular short-axis slices showed no significant difference between²⁰¹Tl and FDG activity. Regional fluctuations were similar for FDG and²⁰¹Tl; the highest tracer activities were observed in the lateral wall and the lowest activities in the septum. Finally, pooled data (n=1620 segmental activities) in nine individuals showed a linear correlation (P<0.0001) between²⁰¹Tl and FDG activity: FDG=0.76²⁰¹Tl + 0.23 (r=0.70). These data demonstrate the absence of major differences between regional²⁰¹Tl and FDG activity in normal myocardium, suggesting that no separate²⁰¹Tl and FDG SPET reference values are needed for comparison with patient studies.     

Comparison of fluorine-18 and bromine-76 imaging in positron emission tomography

State of the art positron emission tomography (PET) systems allow for scatter and attenuation correction. However, the size of the structure being studied and the region of interest (ROI) chosen also influence the accuracy of measurements of radioactive concentration. Furthermore, the limited spatial resolution of PET tomographs, which depends, among other factors, on the range of positrons in matter, can also contribute to a loss in quantitation accuracy. In this paper we address the influence of positron range, structure size and ROI size on the quantitation of radioactive concentration using PET. ECAT EXACT HR+ (HR+) and ECAT 953B/31 (ECAT 953B) PET systems were used in phantom acquisitions performed with two radioisotopes with different positron ranges. The 3D Hoffman phantom was scanned on both scanners with both radioisotopes, to visually analyse the image quality. A resolution phantom having six spheres of different diameters in a Plexiglas cylinder was used to calculate the values of the contrast recovery coefficient or hot spot recovery coefficient and of the spill-over or cold spot recovery coefficient under different imaging conditions used in clinical routine at our institution. Activity ratios were varied between 2 and 30 or between 0.4 and 200 by filling the spheres with fluorine-18 or bromine-76 respectively and the cylinder with ¹¹C. Dynamic scans were performed on each scanner. Data were reconstructed using the same parameters as are used in clinical protocols. The variations in sphere and cylinder activities with time were fitted using the function M(t)=k ₁·A(t)+k ₂.B(t), where M(t) is the radioactivity concentration measured in an ROI placed on each sphere and A(t) and B(t) represent the true radioactivity concentrations present at time t in the spheres and in the cylinder respectively. k ₁ and k ₂ are factors representing the contrast recovery coefficient and the spill-over from surrounding activity on measurements respectively. The visual analysis of images obtained using a 3D Hoffman phantom showed that image resolution and image contrast between different regions are radioisotope dependent and clearly better when using ¹⁸F. Linear profiles taken on these images confirmed the visual assessment. For a given scanner, the k ₁ values obtained with ¹⁸F were systematically higher than those measured using ⁷⁶Br in the same machine (especially for the smaller spheres) when using the same ROI. For a sphere of a particular diameter, the use of a wider ROI resulted in lower quantitative accuracy when using the same isotope and the same camera. Lower quantitative accuracy was found for smaller spheres for all ROI sizes used in image analysis. For the same scanner and for a similar imaging situation (same sphere and same ROI), it was found that k ₁ and k ₂ values depend on the radioisotope used. For the same isotope and tomograph, the k ₁ values obtained decreased with the size of the structures imaged, as well as with the increase in ROI size. The use of a tomograph with better spatial resolution (HR+, rather than ECAT 953B) greatly increased the k ₁ values for ¹⁸F while only a mild improvement in these values was observed for ⁷⁶Br. The use of ⁷⁶Br led to k ₂ values that were slightly higher than those measured using ¹⁸F. These differences may have been due to the difference in the range of the positrons emitted by the radioisotopes used in this study. The measurements performed in this study show that the comparison of studies obtained on the same camera depends on the radioisotope used and may require the adaptation of ROI size between examinations. Marked differences are visible if the positron ranges of such radioisotopes are very different. Therefore, when employing commercially available tomographs and imaging protocols used in clinical routine, the effects of differences in positron range on image quality and quantitation are noticeable and correction for these effects may be of importance. With the arrival of PET imaging systems with better spatial resolution (close to 2 mm full-width at half-maximum for animal PET systems), positron range will have an increasing influence on the image quality and on the choice of radioisotope for a given application. Received 30 January and in revised form 18 March 1999     

Metabolic imaging of the brain stem and spinal cord: studies with positron emission tomography using 18F-2-deoxyglucose in normal and pathological cases

A new high resolution positron emission scanner (Neuro-PET) has made possible clear visualization and quantitation of glucose metabolism in the brain stem and upper cervical cord (above C4) using 18F-2-deoxyglucose. The following mean measurements of the glucose utilization rate are based on studies of 34 normal volunteers and patients with no apparent pathology in the brain stem or cord: 5.0 +/- 1.0 (SD) mg Glu/100 g/min for the mesencephalon-upper pons, 3.2 +/- 1.0 for the pons-medulla, and 1.7 +/- 0.6 for the upper cervical cord. (The first value also includes studies done with the ECAT-II scanner.) Resolution of white-gray matter within these structures was not possible. Whenever possible, a correlation was made with autoradiographic data in monkeys, and good agreement was found. The glucose utilization in cases showing brain stem and cord pathology was altered, with marked elevation (as high as 8.2 mg/100 g/min) in cases of high-grade gliomas, and reduction in cases of low-grade gliomas and one pontine hematoma.     

Diagnosis of a cardiac angiosarcoma by fluorine-18 fluordeoxyglucose positron emission tomography

Cardiac angiosarcoma is a rare tumour entity with a poor prognosis. Early detection is difficult but important for the further course of the disease. We report on a young patient with a tumour of unknown origin and dignity of the right atrium. Magnetic resonance imaging, CT and echocardiography were sufficient in localisation, but no statement on the dignity was possible. Furthermore, staging led to ambiguous results. Malignancy could be proved by fluorine-18 fluordeoxyglucose positron emission tomography, leading to early surgery. Histology revealed a poorly differentiated angiosarcoma.