Anatomical distribution and sclerotic activity of bone metastases from thyroid cancer assessed with F-18 sodium fluoride positron emission tomography.

Currently, bone scintigraphy (BS) is considered to lack sensitivity in detecting bone metastases (BM) from thyroid cancer. We evaluated the anatomical distribution and metabolic behavior of BM as well as the accuracy of BS with and without combination of whole-body iodine scintigraphy (WBI) in detecting metastatic bone disease in thyroid carcinoma. F-18 positron emission tomography (PET), x-ray, BS, and WBI were performed in 35 patients with known or suspected bone metastases from papillary (9 patients) or follicular (26 patients) thyroid carcinoma. Twenty-two metastases were previously known in 14 patients. The indication was staging in 21 patients with high risk for BM, elevated thyroglobulin (Tg)-levels or evaluation of exact extent of BM (14 patients). In addition, results of WBI (35 patients), X-ray (35 patients) F-18 PET (35 patients), MRI of the spine (13 patients), and FDG-PET (15 patients) as well as the clinical course (1.5-4 years) were correlated. BM were detected in 18 patients. Solitary, bifocal, or multiple lesions were present in 9, 2, and 7 patients, respectively. The anatomical distribution of BM (n = 43) was as follows: spine, 42%; skull, 2%; thorax, 16%; femur, 9%; pelvis, 26%; humerus and clavicle, 5%. Sensitivity of BS in interpreting patients as positive or negative for having BM was 64%-85% (specificity, 95%-81%). The combination of BS and WBI was 100% sensitive in detecting metastatic bone disease. One patient had a single BM that was positive at BS but negative on WBI. All metastases were osteolytic on x-ray and two-thirds presented a missing or very limited osteosclerotic bone reaction on F-18 PET. Our data confirm the limited sensitivity of planar BS in detecting BM from thyroid cancer. The combination of BS and WBI, however, was highly accurate. Compared to other malignancies, the distribution pattern of BM presented a lower percentage of vertebral metastases and more patients with single metastases. Those findings in combination with a missing or only slight osteosclerotic bone reaction explain the limited sensitivity of planar BS alone.

Fluorine-18 2-deoxy-2-fluoro-D-glucose PET in the preoperative staging of breast cancer: comparison with the standard staging procedures.

The present study compared the diagnostic accuracy of fluorine-18 2-deoxy-2-fluoro-D-glucose positron emission tomography (FDG-PET) with conventional staging techniques. The differentiation between malignant and benign lesions and the detection of multifocal disease, axillary and internal lymph node involvement, and distant metastases were evaluated. One hundred and seventeen female patients were prospectively examined using FDG-PET and conventional staging methods such as chest X-ray, ultrasonography of the breast and liver, mammography and bone scintigraphy. All patients were examined on a modern full-ring PET scanner. Histopathological analysis of resected specimens was employed as the reference method. The readers of FDG-PET were blinded to the results of the other imaging methods and to the site of the breast tumour. The sensitivity and specificity of FDG-PET in detecting malignant breast lesions were 93% and 75% respectively. FDG-PET was twofold more sensitive (sensitivity 63%, specificity 95%) in detecting multifocal lesions than the combination of mammography and ultrasonography (sensitivity 32%, specificity 93%). Sensitivity and specificity of FDG-PET in detecting axillary lymph node metastases were 79% and 92% (41% and 96% for clinical evaluation). FDG-PET correctly indicated distant metastases in seven patients. False-positive or false-negative findings were not encountered with FDG-PET. Chest X-ray was false-negative in three of five patients with lung metastases. Bone scintigraphy was false-positive in four patients. Three patients were upstaged since FDG-PET detected distant metastases missed with the standard staging procedure. It is concluded that, compared with the imaging methods currently employed for initial staging, FDG-PET is as accurate in interpreting the primary tumour and more accurate in screening for lymph node metastases and distant metastases. Due to a false-negative rate of 20% in detecting axillary lymph node metastases, FDG-PET cannot replace histological evaluation of axillary status.

Grading of tumors and tumorlike lesions of bone: evaluation by FDG PET.

UNLABELLED: Clinical diagnosis of skeletal tumors can be difficult, because such lesions compose a large, heterogeneous group of entities with different biologic behaviors. The aim of this prospective study was to assess the value of PET in grading tumors and tumorlike lesions of bone. METHODS: Two hundred two patients with suspected primary bone tumors were investigated using FDG PET. Uptake of FDG was evaluated semiquantitatively by determining the tumor-to-background ratio (T/B). All patients underwent biopsy, resulting in the histologic detection of 70 high-grade sarcomas, 21 low-grade sarcomas, 40 benign tumors, 47 tumorlike lesions, 6 osseous lymphomas, 6 plasmacytomas, and 12 metastases of an unknown primary tumor. RESULTS: All lesions, with the exception of 3 benign tumors, were detected by increased FDG uptake. Although sarcomas showed significantly higher T/Bs than did latent or active benign lesions (P < 0.001), aggressive benign lesions could not be distinguished from sarcomas. Using a T/B cutoff level for malignancy of 3.0, the sensitivity of FDG PET was 93.0%, the specificity was 66.7%, and the accuracy was 81.7%. CONCLUSION: FDG PET provides a promising tool for estimating the biologic activity of skeletal lesions, implicating consequences for the choice of surgical strategy.

FDG positron emission tomography in the diagnosis of peripheral pulmonary focal lesions.

Positron emission tomography (PET) using fluoride-18-marked fluoride deoxyglucose (FDG) represents a metabolically based imaging technique capable of providing information on the potential malignancy of peripheral pulmonary focal lesions. In the present prospective study, we investigated the effectiveness of FDG-PET in determining the dignities of 67 such lesions in 35 patients. Findings of FDG-PET were compared with those of computed tomography (CT), as well as with surgical and histological reports, and the value of FDG-PET as a diagnostic method evaluated. FDG-PET correctly identified 38 lesions as positive for malignancy, 18 correctly as negative, 7 incorrectly as negative, and 4 incorrectly as positive. Based on lesions, this yields a sensitivity of 84.4% and a specificity of 81.8%. All malignant focal lesions with a diameter of over 1.2 cm were correctly identified (sensitivity: 100%). In cases of intense FDG uptake, differentiation between a primary lesion, a metastasis, and an acute inflammation is often not possible.

How useful is positron emission tomography for lymphnode staging in non-small-cell lung cancer?

UNLABELLED: The introduction of positron emission tomography (PET) raises the question of the new method's capabilities in the staging of mediastinal lymphnodes, since PET differentiates between metabolically active and inactive tissues. 80 patients with histologically confirmed non-small-cell lung cancer (NSCLC) underwent PET scanning with 18-F-marked fluorodeoxyglucose (FDG). Extensive dissection of mediastinal lymphnodes (18-28 lymphnodes recovered) was performed in 78 cases. Metastasis to mediastinal lymphnodes were observed in 25 patients (N2: 22; N3: 3). RESULTS: Primary Tumor: FDG-PET showed significant enhancement of the primary tumor in 78 of 80 patients (sensitivity: 97%). Lymphnode Involvement: FDG-PET was positive in 23 of 25 patients with surgically confirmed lymphnode involvement (sensitivity: 92%). After a median follow up interval of 18 months, 11 patients with false positive lymphnode uptake were still alive; 10 of them showed no tumor recurrency. On the basis of these findings, enlarged mediastinal lymphnodes visualized at CT, but negative at FDG-PET are free of metastatic involvement with a sensitivity of 92%. FDG uptake of mediastinal lymphnodes at PET, however, should not be interpreted as proof of malignancy.

Experience with carbon-11 choline positron emission tomography in prostate carcinoma.

We investigated the potential of carbon-11 choline positron emission tomography (PET) for the detection of lymph node and bone metastases in prostate cancer. A total of 23 patients were studied (known metastases: 8; suspicion of metastases: 3; primary staging: 12). Whole-body PET imaging was performed 5 min after injection of the tracer and completed within 1 h. Focally increased tracer uptake in bone or abdominal lymph node regions was interpreted as representing tumour involvement. All known bone and lymph node metastases could be recognized by [11C]choline PET. One out of ten negative scans for primary staging was false-negative (lymph node <1 cm) and one out of two positive scans was false-positive with regard to lymph node involvement (focal bowel activity). It is concluded that [11C]choline PET is a promising new tool for the primary staging of prostate cancer, with lymph node and bone metastases demonstrating high tracer uptake. Therapeutic management could be influenced by these results in that the technique may permit avoidance of surgical lymph node exploration.

Early detection and accurate description of extent of metastatic bone disease in breast cancer with fluoride ion and positron emission tomography.

PURPOSE: Previous studies have shown that bone metastases are revealed by magnetic resonance imaging (MRI) or bone marrow scintigraphy several months before they are visible by conventional bone scintigraphy (BS). We present a new approach for detecting bone metastases in patients with breast cancer. We compared findings obtained with fluoride ion (F-18) and positron emission tomography (PET) with those obtained with conventional BS. PATIENTS AND METHODS: Thirty-four breast cancer patients were prospectively examined using F-18-PET and conventional BS. F-18-PET and BS were performed within 3 weeks of each other. Metastatic bone disease was previously known to be present in six patients and was suspected (bone pain or increasing levels of tumor markers, Ca(2+), alkaline phosphatase) in 28 patients. Both imaging modalities were compared by patient-by-patient analysis and lesion-by-lesion analysis, using a five-point scale for receiver operating characteristic (ROC) curve analysis. A panel of reference methods was used, including MRI (28 patients), planar x-ray (17 patients), and spiral computed tomography (four patients). RESULTS: With F-18-PET, 64 bone metastases were detected in 17 patients. Only 29 metastases were detected in 11 patients with BS. As a result of F-18-PET imaging, clinical management was changed in four patients (11.7%). For F-18-PET, the area under the ROC curve was 0.99 on a lesion basis (for BS, it was 0.74; P <.05) and 1.00 on a patient basis (for BS, it was 0.82; P <.05). CONCLUSION: F-18-PET demonstrates a very early bone reaction when small bone marrow metastases are present, allowing accurate detection of breast cancer bone metastases. This accurate detection has a significant effect on clinical management, compared with the effect on management brought about by detection with conventional BS.

Sensitivity in detecting osseous lesions depends on anatomic localization: planar bone scintigraphy versus 18F PET.

UNLABELLED: Radionuclide bone scanning (RNB) is considered to be the most practical screening technique for assessing the entire skeleton for skeletal metastases. However, RNB has been shown to be of lower sensitivity than MRI and CT in detecting osteolytic metastases. A prospective study was designed to evaluate the accuracy of planar RNB versus tomographic bone imaging with 18F-labeled NaF and PET (18F PET) in detecting osteolytic and osteoblastic metastases and its dependency on their anatomic localization. METHODS: Forty-four patients with known prostate, lung or thyroid carcinoma were examined with both planar RNB and 18F PET. A panel of reference methods including MRI of the spine, 1311 scintigraphy, conventional radiography and spiral CT was used as the gold standard. RNB and 18F PET were compared by a lesion-by-lesion analysis using a five-point score for receiver operating characteristic (ROC) curve analysis. RESULTS: 18F PET showed 96 metastases (67 of prostate carcinoma and 29 of lung or thyroid cancer), whereas RNB revealed 46 metastases (33 of prostate carcinoma and 13 of lung or thyroid cancer). All lesions found with RNB were also detected with 18F PET. Compared with 18F PET and the reference methods, RNB had a sensitivity of 82.8% in detecting malignant and benign osseous lesions in the skull, thorax and extremities and a sensitivity of 40% in the spine and pelvis. The area under the ROC curve was 0.99 for 18F PET and 0.64 for RNB. CONCLUSION: 18F PET is more sensitive than RNB in detecting osseous lesions. With RNB, sensitivity in detecting osseous metastases is highly dependent on anatomic localization of these lesions, whereas detection rates of osteoblastic and osteolytic metastases are similar. Higher detection rates and more accurate differentiation between benign and malignant lesions with 18F PET suggest the use of 18F PET when possible.

Evaluation of neoadjuvant therapy response of osteogenic sarcoma using FDG PET.

UNLABELLED: According to the current treatment protocol of the Cooperative Osteosarcoma Study (COSS), monitoring preoperative chemotherapy response and estimating grade of tumor regression in patients with osteosarcoma is mandatory before surgical removal of the tumor, particularly if a limb salvage procedure is intended. In addition, response to neoadjuvant chemotherapy is considered as an important prognostic indicator. The aim of this prospective study was to assess the usefulness of 2-(18F) fluoro-2-deoxy-D-glucose (FDG) PET in the noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. METHODS: In 27 patients with osteosarcoma, we determined tumor-to-background ratios (TBRs) of FDG uptake with PET, before and after neoadjuvant chemotherapy according to COSS 86c or COSS 96 protocols, respectively. We compared changes in glucose metabolism of osteosarcomas with the histologic grade of regression in the resected specimen, according to Salzer-Kuntschik, discriminating responders (grades I-III; n = 17) and nonresponders (grades IV-VI; n = 10). RESULTS: The decrease of FDG uptake in osteosarcomas expressed as a ratio of posttherapeutic and pretherapeutic TBRs showed a close correlation to the amount of tumor necrosis induced by polychemotherapy (P < 0.001; Spearman). With a TBR ratio cutoff level of 0.6, all responders and 8 of 10 nonresponders could be identified by PET. In addition, lung metastases of osteosarcoma were detected with FDG PET in 4 patients. CONCLUSION: FDG PET provides a promising tool for noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. This could imply consequences for the choice of surgical strategy, because a limb salvage procedure cannot be recommended in patients nonresponsive to preoperative chemotherapy unless wide surgical margins can safely be achieved.

Fluorodeoxyglucose positron emission tomography of soft tissue tumours: is a non-invasive determination of biological activity possible?

Since musculoskeletal tumours comprise a large heterogeneous group of entities with different biological behaviour, clinical diagnosis of such lesions can be very difficult. The aim of this prospective study was to assess the usefulness of 2-[F-18]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in the non-invasive evaluation of soft tissue tumours. One hundred and two patients with suspected soft tissue neoplasms were investigated by FDG-PET. The uptake of FDG was evaluated semiquantitatively by determining the tumour to background ratio (TBR). All patients underwent biopsy, resulting in the histological detection of 39 high-grade sarcomas, 16 intermediate-grade sarcomas, 11 low-grade sarcomas, 25 benign tumours, 10 tumour-like lesions such as spontaneous myositis ossificans (n = 6) and one non-Hodgkin lymphoma. All lesions except for two lipomas disclosed an increased FDG uptake. Sarcomas showed significantly higher TBR values than latent or active benign lesions (P<0.001) and aggressive benign lesions (P<0.05). Using a TBR cut-off level of 3.0 for malignancy, sensitivity of FDG-PET was 97.0%, specificity 65.7% and accuracy 86. 3%. From our data there are three main conclusions: (1) Except for patients with pseudotumoral myositis ossificans, lesions with a TBR >3 were sarcomas (91.7%) or aggressive benign tumours (8.3%). (2) Tumours with a TBR <1.5 were latent or active benign lesions, exclusively. (3) The group with intermediate TBR values (<3 and >1. 5) comprised primarily latent or active benign lesions, but also four aggressive benign tumours and two low-grade sarcomas. Our data suggest that FDG-PET represents a useful tool for the evaluation of the biological activity of soft tissue neoplasms.

Role of attenuation correction for fluorine-18 fluorodeoxyglucose positron emission tomography in the primary staging of malignant lymphoma.

Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has been shown to improve the diagnostic accuracy in the staging of malignant lymphomas, based on the metabolic signal of the lesions. This study was undertaken to determine the effect of attenuation correction in the detection of nodal and extranodal lesions in the primary staging of malignant lymphomas. Fifty-one untreated patients with either non-Hodgkin lymphoma (NHL, n=29) or Hodgkin's disease (n=22) were retrospectively evaluated. Static FDG-PET imaging of the trunk was performed following administration of 250-350 MBq FDG. Attenuation correction was performed in all patients. Images were reconstructed iteratively with or without transmission scans. Image evaluation was performed independently by two observers, who each examined one set of images (i.e. attenuation-corrected or uncorrected). The final decision as to whether results were discordant was reached by consensus of both observers. Out of 593 evaluated lymph node regions, 187 regions of increased FDG uptake were identified by both techniques. Differences between the readers concerned mainly the anatomical assignment of lesions (n=33) or the status (benign/malignant) of individual lesions (n=24). However, direct comparison of the two sets of images demonstrated very similar lesion contrast on attenuation-corrected and non-attenuation-corrected images. Real differences could be determined only in five regions (neck, 1; mediastinum, 1; upper abdomen, 3). Thirty-seven extranodal lesions (including lung, liver, spleen, bone marrow and soft tissue) were detected by both techniques without significant differences. It is concluded that in this study, attenuation correction did not improve the diagnostic accuracy of FDG-PET in the detection of lymph node or organ involvement during the primary staging of malignant lymphomas. Of more importance seemed to be the experience of the reader regarding the classification of a lesion's status the anatomical assignment, knowledge of physiological uptake and artefacts, and systematic and skillful examination of all regions scanned.

Fluorine-18-FDG PET and technetium-99m antigranulocyte antibody scintigraphy in chronic osteomyelitis.

UNLABELLED: The aim of this study was to assess the usefulness of PET with 2-18F-fluoro-2-deoxy-D-glucose (FDG), as compared to immunoscintigraphy (IS) with 99mTc-labeled monoclonal antigranulocyte antibodies (AGAbs), in the detection of chronic osteomyelitis. METHODS: Fifty-one patients suspected of having chronic osteomyelitis in the peripheral (n = 36) or central (n = 15) skeleton were evaluated prospectively with static FDG PET imaging and combined 99mTc-AGAb/99mTc-methylene diphosphonate (MDP) bone scanning within 5 days. FDG PET and IS were evaluated in a blinded and independent manner by visual interpretation, which was graded on a five-point scale of two observers' confident diagnosis of osteomyelitis. Receiver operating characteristic (ROC) curve analysis was performed for both imaging modalities. The final diagnosis was established by means of bacteriologic culture of surgical specimens and histopathologic analysis (n = 31) or by biopsy and clinical follow-up over 2 yr (n = 20). RESULTS: Of 51 patients, 28 had osteomyelitis and 23 did not. According to the unanimous evaluation of both readers, FDG PET correctly identified 27 of the 28 positives and 22 of the 23 negatives (IS identified 15 of 28 positives and 17 of 23 negatives, respectively). The area under the ROC curve was 0.97/0.97 (reader 1/reader 2) for FDG PET and 0.87/0.90 for IS, with a high degree of interobserver concordance (K-values were 0.96 for FDG PET and 0.91 for IS). In the central skeleton, the ROC curve area was 0.98/1.00 for FDG PET and 0.71/0.77 for IS (p<0.05). On the basis of ROC analysis, the overall accuracies of FDG PET and IS in the detection of chronic osteomyelitis were 96%/96% and 82%/ 88%, respectively. With regard to the optimal threshold values, sensitivity and specificity were 100%/97% and 95%/95% with FDG PET, compared to 86%/92% and 77%/82% with IS, respectively. CONCLUSION: In the peripheral skeleton, both FDG PET and combined 99mTc-AGAb/99mTc-MDP scanning are appropriate imaging modalities to diagnose chronic osteomyelitis. FDG PET additionally allows reliable differentiation between osteomyelitis and infection of the surrounding soft tissue. In the central skeleton within active bone marrow, FDG PET is highly accurate and superior to AGAb imaging in the diagnosis of chronic osteomyelitis, which frequently presents as a nonspecific photopenic lesion at scintigraphy with labeled white blood cells.

Pharmacokinetics of 99Tcm-pertechnetate and 188Re-perrhenate after oral administration of perchlorate: option for subsequent care after the use of liquid 188Re in a balloon catheter.

Radioactive wires and other linear sources are currently being used in clinical trials as endovascular brachytherapy to prevent restenosis after percutaneous transluminal coronary angioplasty. A new concept is the use of a liquid-filled balloon containing a beta-emitting radioisotope. A major advantage is optimal delivery of the radioactivity to the vessel wall. Rhenium-188 (188Re) is a high-energy beta-emitter that is routinely available from a 188W/188Re generator in liquid form. Since 188Re-perrhenate could be released in the unlikely event of balloon rupture, we investigated whether, in analogy to pertechnetate, subsequent use of perchlorate can reduce the uptake of perrhenate in the thyroid. We performed static (n = 9) and dynamic (n = 11) thyroid scintigraphy with 99Tcm-pertechnetate to estimate the overall reduction in activity within 30 min and the washout from the thyroid after oral administration of 600 mg perchlorate (T1/2). In two patients, 188Re was injected to estimate the whole-body distribution and the discharge of thyroid activity after perchlorate use. Based on MIRD Dose Estimate Report No. 8 (valid for 99Tcm-pertechnetate), the radiation burden was calculated for intravenous administration of 188Re and competitive blocking with perchlorate. In 20 patients, 99Tcm uptake by the thyroid was reduced by 85% within 30 min by perchlorate. The mean (+/- S.D.) washout rate (T1/2) was 8 +/- 2 min in 11 patients. Perrhenate showed a whole-body distribution similar to that of pertechnetate and the thyroid activity could be displaced (T1/2 = 6.3 and 9.3 min, respectively) by oral administration of perchlorate, with reductions in uptake of 83% and 75% within 30 min, respectively. Whole-body scanning demonstrated no regional accumulation of 188Re-perrhenate with excretion by urine. Dose estimates gave an effective dose equivalent of 0.42 mSv MBq-1, which decreased to 0.16 mSv MBq-1 after perchlorate blocking. 188Re has favourable properties for endovascular brachytherapy via a balloon catheter and, in the unlikely event of balloon rupture, whole-body radiation can be reduced to 38% by subsequent oral administration of perchlorate.

[Positron-emission tomography in the diagnosis of abdominal tumors]. / Positronen-Emissions-Tomographie in der Diagnostik abdomineller Tumore.

PET is recognized as a powerful imaging research tool. Its clinical application has been increasing significantly in recent years. Based on pathophysiological and biochemical principles, functional PET imaging makes it possible to assess parameters of tumor biology not easily accessible to conventional imaging, such as metabolic activity, proliferation, adrenergic transmitter uptake or accumulation of cytostatics in individual tumor manifestations. For clinical application, PET imaging with 2-[F-18]fluorodeoxyglucose (FDG) is of paramount importance. This article reviews recent developments in the use of PET in the diagnosis of abdominal malignant tumors. Diagnosis of pancreatic carcinoma and related liver metastases, locoregional and distant recurrence, as well as therapy control of colorectal cancer, nodal and extranodal staging and therapy monitoring of malignant lymphoma, can be reliably performed with PET. Several appropriately labeled adrenergic transmitters are currently being developed for specific imaging of neuroendocrine tumors. Radiolabeled cytostatics such as F-18 5-FU will shortly be available for clinical use as probes for primary or secondary cytostatic resistance. Encouraging clinical results and attractive new imaging concepts promise increasing use and importance for PET for imaging of abdominal malignancies.

Chronic osteomyelitis: detection with FDG PET and correlation with histopathologic findings.

PURPOSE: To evaluate use of positron emission tomography (PET) with 2-(fluorine-18) fluoro-2-deoxy-D-glucose (FDG) in detection of chronic osteomyelitis. MATERIALS AND METHODS: Thirty-one patients suspected to have chronic osteomyelitis in the peripheral (n = 21) or central (n = 10) skeleton were evaluated prospectively with FDG PET. Analysis of the receiver operating characteristic curve was performed. The final diagnosis was made by means of bacteriologic culture of surgical specimens and histopathologic analysis. RESULTS: FDG PET allowed identification of 17 of 18 patients with osteomyelitis and 12 of 13 without osteomyelitis. There was one false-positive and one equivocal result. The area under the ROC curve was 0.96 for all patients, 1.00 for patients suspected to have osteomyelitis in the peripheral skeleton, and 0.88 for patients suspected to have osteomyelitis in the central skeleton. The overall accuracy of FDG PET was 97% with a high degree of interobserver concordance (kappa = 0.93). The overall sensitivity and specificity were 100% and 92%, respectively. CONCLUSION: FDG PET enables noninvasive detection and demonstration of the extent of chronic osteomyelitis with a high degree of accuracy. Especially in the central skeleton within active bone marrow, FDG PET is highly accurate and shows great promise in diagnosis of chronic osteomyelitis.

18-F-fluorodeoxyglucose-positron emission tomography as a new approach to detect lymphomatous bone marrow.

PURPOSE: Bone marrow involvement in patients with malignant lymphoma is considered a sign of generalized disease with less favorable prognosis. Bone marrow biopsy (BMB), which represents the standard diagnostic procedure, however, is associated with a high rate of false-negative findings, which may lead to errors in management. The present study was undertaken to investigate the efficacy of positron emission tomography (PET) with 18-F-fluorodeoxyglucose (FDG-PET) as a new method to evaluate bone marrow involvement in patients with malignant lymphoma. METHODS: Seventy-eight consecutive, untreated patients with either non-Hodgkin's lymphoma (NHL; n = 39) or Hodgkin's disease (HD; n = 39) were prospectively evaluated. Static FDG-PET imaging was performed following application of 270 MBq (F-18)-FDG. Attenuation correction was performed in 63 of 78 patients. Visual evaluation was performed by two examiners unaware of the clinical data. Material for BMB (70 bilateral, 8 unilateral) was obtained from the posterior iliac crest. Discordant results of PET and biopsy were settled, when possible, on the basis of further biopsy or magnetic resonance imaging (MRI). RESULTS: In addition to seven concordant positive and 57 concordant negative findings, biopsy revealed another four cases with bone marrow involvement not detectable by FDG-PET analysis (+5.1%). On the contrary, PET showed bone marrow areas of intensive FDG uptake that suggested bone marrow lymphoma in 10 patients with negative biopsies (+12.8%). In eight patients, FDG-PET findings were confirmed by either histologic verification (n = 4), MRI (n = 2), polymerase chain reaction (PCR) for rearranged immunoglobulin H sequences (n = 1), or clinical presentation (n = 1). Two cases remained unresolved. CONCLUSION: The results indicate that FDG-PET has a high potential to detect bone marrow involvement in malignant lymphoma. Besides confirming lesions found at BMB, FDG-PET provided additional information, which, in eight of 78 patients (10.3%), led to an upgrade of the tumor stage.

Extranodal malignant lymphoma: detection with FDG PET versus CT.

PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesions not visualized at FDG PET were identified at CT, six of which were verified with biopsy (n = 2) or follow-up (n = 4) results. Five of these six CT findings were found to be erroneous. In 13 patients, PET findings led to changes in tumor staging. CONCLUSION: PET may provide more information about extranodal lymphoma than does incremental CT.

Lymphoma: role of whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) PET in nodal staging.

PURPOSE: To compare 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET) with computed tomography (CT) in primary nodal staging of malignant lymphoma. MATERIALS AND METHODS: Sixty consecutive patients with untreated, histopathologically proved malignant lymphoma (aged 7-72 years; 33 with non-Hodgkin lymphoma, 27 with Hodgkin disease) underwent FDG PET and contrast material-enhanced CT for nodal staging. Lymph node regions identified at both CT and PET were regarded as actual locations of disease. Discordant results were verified with biopsy or clinical follow-up whenever possible. RESULTS: One hundred sixty of 740 evaluated lymph node regions were identified as diseased at both CT and PET. Of the 25 additional regions seen with PET, seven were true-positive; two, false-positive; and 16, unresolved. CT showed six additional disease manifestations; three were false-positive, and three were unresolved. Staging was changed in the four patients with the seven confirmed additional PET findings: from stage I to II in one patient and from stage II to III in three patients. Staging was changed from stage II to I in one of the three patients with false-positive CT findings. CONCLUSION: FDG PET may be more accurate for detecting nodal lymphoma than incremental CT.

Lymph node staging in non-small cell lung cancer: evaluation by [18F]FDG positron emission tomography (PET).

BACKGROUND: A study was undertaken to investigate the accuracy of positron emission tomography (PET) with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) in the thoracic lymph node staging of non-small cell lung cancer (NSCLC). METHODS: Forty six patients with focal pulmonary tumours who underwent preoperative computed tomographic (CT) and FDG-PET scanning were evaluated retrospectively. Thirty two patients had NSCLC and 14 patients had a benign process. The final diagnosis was established by means of histopathological examination at thoracotomy, and the nodal classification in patients with lung cancer was performed by thorough dissection of the mediastinal nodes at surgery. RESULTS: FDG-PET was 80% sensitive, 100% specific, and 87.5% accurate in staging thoracic lymph nodes in patients with NSCLC, whereas CT scanning was 50% sensitive, 75% specific, and 59.4% accurate. The absence of lymph node tumour involvement was identified by FDG-PET in all 12 patients with NO disease compared with nine by CT scanning. Lymph node metastases were correctly detected by FDG-PET in three of five patients with N1 disease compared with two by CT scanning, in nine of 11 with N2 disease compared with six by CT scanning, an in all four with N3 nodes compared with two by CT scanning. CONCLUSIONS: FDG-PET provides a new and effective method for staging thoracic lymph nodes in patients with lung cancer and is superior to CT scanning in the assessment of hilar and mediastinal nodal metastases. With regard to resectability, FDG-PET could differentiate reliably between patients with N1/N2 disease and those with unresectable N3 disease.

[Clinical value of positron emission tomography (PET) in oncologic questions: results of an interdisciplinary consensus conference. Schirmerreschaft der Deutschen Gesellschaft for Nuklearmedizin]. / Klinische Wertigkeit der Positronen-Emissions-Tomographie (PET) bei onkologischen Fragestellungen: Ergebnisse einer interdisziplinären Konsensuskonferenz.

AIM: The purpose of the present paper is to assess clinical value of PET in oncology on the basis of published studies. METHODS: Clinical value of PET in oncology was evaluated by a panel of recognized experts in the framework of an interdisciplinary consensus conference. On the basis of PET studies, well documented in the international literature, the value of PET for solving clinical questions was classified according to the following categories (classes 1a, 1b, 2a, 2b, 3): "appropriate" (1a), "mostly acceptable" (1b), "helpful" (2a), "value as yet unknown" (2b), "useless" (3). RESULTS: 2-fluorodeoxyglucose (FDG) acts as the radiopharmaceutical of choice for PET in clinical oncology. PET is indicated (1a) for diagnosing relapse in high grade glioma (FDG) or low grade glioma (C-11 methionine or F-18 fluorotyrosine), differential diagnosis of solitary peripheral pulmonary nodules in high risk patients and for diagnosis of pancreatic carcinoma. PET may be clinically used (1b): In "low-grade" glioma, search for unknown primary in head and neck tumors, suspicion of relapse in non-small cell bronchial carcinoma (NSCBC) and colorectal carcinoma, lymphnode staging in NSCBC, pancreatic carcinoma, muscle invasive bladder carcinoma and testicular cancer. Staging of Hodgkin's disease (HD, stage I/II vs III), early therapy control in patients with a residual mass or suspicion of relapse in HD and in high grade NHL, lymph node staging and search for distant metastases in malignant melanoma (Breslow > 1.5 mm), search for lymph node or distant metastases in differentiated thyroid cancer with elevated hTG and a negative radioiodide whole body scan. Many further indications are emerging, but are not yet sufficiently well documented in the literature. For most indications beside scientific studies, an individual cost benefit utility evaluation by the responsible physician is recommended. CONCLUSION: Metabolic imaging of PET provides for many principle advantages compared to conventional anatomically based cross sectional imaging. For routine use in oncology a detailed assessment of specific efficiency of PET is indicated.