Bone marrow uptake of fluorine-18-fluorodeoxyglucose following treatment with hematopoietic growth factors: initial evaluation

Imaging haemopoietic stem cells and microenvironment dynamics through transplantation

Understanding the subclinical pathway to cellular engraftment following haemopoietic stem cell transplantation (HSCT) has historically been limited by infrequent marrow biopsies, which increase the risk of infections and might poorly represent the health of the marrow space. Nuclear imaging could represent an opportunity to evaluate the entire medullary space non-invasively, yielding information about cell number, proliferation, or metabolism. Because imaging is not associated with infectious risk, it permits assessment of neutropenic timepoints that were previously inaccessible. This Viewpoint summarises the data regarding the use of nuclear medicine techniques to assess the phases of HSCT: pre-transplant homoeostasis, induced aplasia, early settling and engraftment of infused cells, and later recovery of lymphocytes that target cancers or mediate tolerance. Although these data are newly emerging and preliminary, nuclear medicine imaging approaches might advance our understanding of HSCT events and lead to novel recommendations to enhance outcomes.

Diffuse Skeletal Uptake on 18F-Fluoro-2-Deoxy-d-glucose Positron Emission Tomography/Computed Tomography Scan in a Patient with Acute Lymphoblastic Leukemia: A Typical Superscan Pattern Resembling NaF Positron Emission Tomography Scan

A 65-year-old patient with acute lymphoblastic leukemia presented for an 18fluoro-2-deoxy-d-glucose positron emission tomography computed tomography (18FDG PET) after several courses of chemotherapy for metastatic evaluation. Unexpectedly, on 18FDG PET scan, no discernible uptake was observed in the visceral organs, but instead, the skeleton/bone marrow showed homogenously intense metabolic activity. The distribution of 18FDG observed on the scan was remarkably similar to that on the NaF PET scan, indicating a superscan appearance.

18F-FDG PET/CT Radiomic Analysis with Machine Learning for Identifying Bone Marrow Involvement in the Patients with Suspected Relapsed Acute Leukemia

¹⁸F-FDG PET / CT is used clinically for the detection of extramedullary lesions in patients with relapsed acute leukemia (AL). However, the visual analysis of ¹⁸F-FDG diffuse bone marrow uptake in detecting bone marrow involvement (BMI) in routine clinical practice is still challenging. This study aims to improve the diagnostic performance of ¹⁸F-FDG PET/CT in detecting BMI for patients with suspected relapsed AL.

Methods: Forty-one patients (35 in training group and 6 in independent validation group) with suspected relapsed AL were retrospectively included in this study. All patients underwent both bone marrow biopsy (BMB) and ¹⁸F-FDG PET/CT within one week. The BMB results were used as the gold standard or real “truth” for BMI. The bone marrow ¹⁸F-FDG uptake was visually diagnosed as positive and negative by three nuclear medicine physicians. The skeletal volumes of interest were manually drawn on PET/CT images. A total of 781 PET and 1045 CT radiomic features were automatically extracted to provide a more comprehensive understanding of the embedded pattern. To select the most important and predictive features, an unsupervised consensus clustering method was first performed to analyze the feature correlations and then used to guide a random forest supervised machine learning model for feature importance analysis. Cross-validation and independent validation were conducted to justify the performance of our model.

Results: The training group involved 16 BMB positive and 19 BMB negative patients. Based on the visual analysis of ¹⁸F-FDG PET, 3 patients had focal uptake, 8 patients had normal uptake, and 24 patients had diffuse uptake. The sensitivity, specificity, and accuracy of visual analysis for BMI diagnosis were 62.5%, 73.7%, and 68.6%, respectively. With the cross-validation on the training group, the machine learning model correctly predicted 31 patients in BMI. The sensitivity, specificity, and accuracy of the machine learning model in BMI detection were 87.5%, 89.5%, and 88.6%, respectively, significantly higher than the ones in visual analysis (P < 0.05). The evaluation on the independent validation group showed that the machine learning model could achieve 83.3% accuracy.

Conclusions:¹⁸F-FDG PET/CT radiomic analysis with machine learning model provided a quantitative, objective and efficient mechanism for identifying BMI in the patients with suspected relapsed AL. It is suggested in particular for the diagnosis of BMI in the patients with ¹⁸F-FDG diffuse uptake patterns.

Increased bone marrow SUVmax on 18F-FDG PET is associated with higher pelvic treatment failure in patients with cervical cancer treated by chemoradiotherapy and brachytherapy

The aim of this study was to evaluate if bone marrow (BM) SUVmax measured on pre-treatment 18F-FDG PET/CT predicts the clinical outcome of locally advanced cervical cancer (LACC). We recruited retrospectively patients with LACC who underwent staging 18F-FDG PET/CT and had baseline blood tests, then treated by chemoradiation therapy (CRT), followed by image-guided adaptive brachytherapy (IGABT). BM SUVmax was calculated and correlated to inflammatory blood markers. Tumor size and pelvic lymph node involvement were evaluated on baseline MRI. Prognostic value of SUV uptake and blood markers regarding overall survival (OS), pelvic and extra-pelvic recurrence-free survival (PRFS and EPRFS respectively) was assessed using Cox models with adjusted p-values. 116 patients with FIGO stage Ib-IVa cervical cancer, treated between 2005 and 2014, were analyzed. The median follow-up was 75.5 months. BM SUVmax was significantly correlated to tumor SUVmax. In multivariate analysis, PRFS was significantly poorer in patients with high BM SUVmax (>2.8) and neutrophilia (p < .05). Tumor size (>5 vs ≤5 cm) could predict PRFS, EPRFS and OS (p < .05). In our cohort, FIGO stage (I-II vs III-IV), pelvic lymph node involvement and tumor SUVmax (>12 vs ≤12) were not prognostic for OS or pelvic and extra-pelvic relapses. Patients with LACC and high BM SUVmax on 18F-FDG PET have worse PFRS following CRT plus IGABT. These results can be potentially explained by the pro-inflammatory role of the tumor microenvironment and G-CSF expressed by tumor cells. These data support the role of PET as a potential indicator of disease aggressiveness beyond tumor staging.

Is it sufficient to evaluate bone marrow involvement in newly diagnosed lymphomas using 18F-FDG PET/CT and/or routine iliac crest biopsy? A new approach of PET/CT-guided targeted bone marrow biopsy

BACKGROUND

To investigate whether PET/CT-guided bone marrow biopsy adds complementary information for evaluation of bone marrow involvement (BMI) in newly diagnosed lymphomas.

METHODS

Patients with newly diagnosed lymphomas that received both ¹⁸F-FDG PET/CT and bone marrow biopsy (BMB) were included in this retrospective study. PET/CT classification of bone lesions was classified as isolated, multifocal (2 lesions or more), diffuse (homogeneous uptake of the entire axial skeleton), or negative. BMBs included PET/CT-guided targeted BMB and/or the routine unilateral iliac crest biopsy. Of 34 patients with focal lesions on PET/CT scan, 30 received both PET/CT-guided targeted BMB and iliac crest biopsy, and 4 patients received targeted biopsy without iliac crest biopsy. The final diagnosis of BMI depends on BMB results.

RESULTS

A total of 299 patients with lymphomas were included. PET/CT classification of bone lesions was isolated (16/5.4%), multifocal (67/22.4%), diffuse (52/17.4%), and negative (164/54.8%). If only positive iliac crest biopsy was considered as the reference standard, the sensitivity of ¹⁸F-FDG PET/CT for identifying focal and diffuse BMI was 48 and 56%, respectively, and the respective specificities were 70 and 83%. Three of 30 patients (10.0%) with focal lesions on PET/CT were confirmed to be false-positive by targeted BMB, and 25 of 30 patients (83.3%) with focal lesions on PET/CT were confirmed as false-negative by iliac crest biopsy.

CONCLUSION

It is insufficient to evaluate BMI in newly diagnosed lymphomas using both ¹⁸F-FDG PET/CT and routine iliac crest biopsy. ¹⁸F-FDG PET/CT imaging should be performed before BMB. In focal bone lesions, PET/CT-guided targeted BMB may complement the results of possible false-positive PET/CT and false-negative iliac crest biopsy findings. However, in diffuse and negative lesions, iliac crest biopsy cannot be safely omitted.

Benign Bone Conditions That May Be FDG-avid and Mimic Malignancy

Positron emission tomography with the radiotracer ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) plays an important role in the evaluation of bone pathology. However, FDG is not a cancer-specific agent, and knowledge of the differential diagnosis of benign FDG-avid bone alterations that may resemble malignancy is important for correct patient management, including the avoidance of unnecessary additional invasive tests such as bone biopsy. This review summarizes and illustrates the spectrum of benign bone conditions that may be FDG-avid and mimic malignancy, including osteomyelitis, bone lesions due to benign systemic diseases (Brown tumor, Erdheim-Chester disease, Gaucher disease, gout and other types of arthritis, Langerhans cell histiocytosis, and sarcoidosis), benign primary bone lesions (bone cysts, chondroblastoma, chondromyxoid fibroma, desmoplastic fibroma, enchondroma, giant cell tumor and granuloma, hemangioma, nonossifying fibroma, and osteoid osteoma and osteoblastoma), and a group of miscellaneous benign bone conditions (post bone marrow biopsy or harvest status, bone marrow hyperplasia, fibrous dysplasia, fractures, osteonecrosis, Paget disease of bone, particle disease, and Schmorl nodes). Several ancillary clinical and imaging findings may be helpful in discriminating benign from malignant FDG-avid bone lesions. However, this distinction is sometimes difficult or even impossible, and tissue acquisition will be required to establish the final diagnosis.

Metabolic Skeletal Superscan on 18F-FDG PET/CT in a Case of Acute Lymphoblastic Leukemia

Superscan is a well-known finding described in skeletal scintigraphy characterized by intense radiotracer uptake in axial skeleton and decreased uptake in soft tissues and kidneys. Metabolic skeletal superscan has also been described in ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in various conditions. We describe here a case of 12-year-old boy who presented with a scalp swelling, progressive pallor, easy fatigability, poor appetite, and fever for 6 months. The initial diagnosis was inconclusive. ¹⁸F-FDG PET/CT revealed metabolic skeletal superscan and the final histopathological diagnosis was acute lymphoblastic leukemia.

Opportunities and limitations of bone marrow biopsy and bone marrow FDG-PET in lymphoma

Bone marrow involvement in lymphoma may have prognostic and therapeutic consequences. Bone marrow biopsy (BMB) is the established method for the evaluation of the bone marrow. (18)F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) plays an important role in lymphoma staging, but its value in the assessment of the bone marrow and whether it can replace BMB is still a topic of debate and investigation. The purpose of this scientific communication is to provide an evidence-based overview about the opportunities and limitations of BMB and FDG-PET in the evaluation of the bone marrow in patients with lymphoma. This article first reviews the basic properties, opportunities and limitations of BMB and bone marrow FDG-PET, and then focuses on the clinical utility of BMB and bone marrow FDG-PET in three major lymphoma subtypes including Hodgkin lymphoma, diffuse large B-cell lymphoma, and follicular lymphoma.

Allogeneic cell transplant expands bone marrow distribution by colonizing previously abandoned areas: an FDG PET/CT analysis

Mechanisms of hematopoietic reconstitution after bone marrow (BM) transplantation remain largely unknown. We applied a computational quantification software application to hybrid 18F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) images to assess activity and distribution of the hematopoietic system throughout the whole skeleton of recently transplanted patients. Thirty-four patients underwent PET/CT 30 days after either adult stem cell transplantation (allogeneic cell transplantation [ACT]; n = 18) or cord blood transplantation (CBT; n = 16). Our software automatically recognized compact bone volume and trabecular bone volume (IBV) in CT slices. Within IBV, coregistered PET data were extracted to identify the active BM (ABM) from the inactive tissue. Patients were compared with 34 matched controls chosen among a published normalcy database. Whole body ABM increased in ACT and CBT when compared with controls (12.4 ± 3 and 12.8 ± 6.8 vs 8.1 ± 2.6 mL/kg of ideal body weight [IBW], P < .001). In long bones, ABM increased three- and sixfold in CBT and ACT, respectively, compared with controls (0.9 ± 0.9 and 1.7 ± 2.5 vs 0.3 ± 0.3 mL/kg IBW, P < .01). These data document an unexpected distribution of transplanted BM into previously abandoned BM sites.

F-18 FDG uptake of bone marrow on PET/CT scan: it's correlation with CD38/CD138 expressing myeloma cells in bone marrow of patients with multiple myeloma

The percentage of myeloma cells in bone marrow is subsequently an important index of disease in patients with multiple myeloma (MM). Bone marrow myeloma cells can be detected by strong CD38/CD138 positivity and light scatter characteristics using flow cytometry. The aim of the study was to evaluate the relationship between the degree of F-18 fluorodeoxyglucose (F-18 FDG) uptake and the percentage of CD38/CD138 expressing myeloma cells in the bone marrow of patients with MM. A total of 31 patients with MM (14 females and 17 males, mean age 59.5 ± 1.9 years, range 29-80 years) were included in the study. All patients underwent FDG-positron emission tomography/computed tomography (PET/CT) scan within 2 weeks after the completion of the usual staging workup for MM, consisting of X-ray skeletal survey and hematological/biochemical parameters including complete blood count, liver and kidney function test, erythrocyte sedimentation rate, serum immunoglobulins, urine light chain excretion, C-reactive protein, β2-microglobulin, and bone marrow plasma cell infiltration. In all patients, flow cytometry was performed for assessing the percentage of CD38/CD138 expressing myeloma cells in the bone marrow samples. The extent of bone marrow FDG uptake on PET/CT scans was visually graduated using a qualitative scoring system as extension score (E-score) and also a semiquantitative scoring system defined as mean standardized uptake value (mSUV) of both femora. There was a statistically significant positive correlation between the percentage of CD38/CD138 expressing plasma cells in bone marrow and both mean qualitative (r = 0.616) and semiquantitative (r = 0.755) results of F-18 FDG uptakes. mSUV and E-score of bone marrow FDG uptake values were also correlated with serum beta-2-microglobulin levels (r = 0.523 and r = 479, respectively). mSUV of bone marrow FDG uptake values were also negatively correlated with serum albumin levels (r = -0.424), whereas there was no correlation between E-score and albumin levels. In conclusion, our results indicate that increased F-18 FDG uptake of bone marrow is related to the percentage of plasma cell infiltration of bone marrow in patients with MM. Therefore, F-18 FDG-PET/CT study may be a useful tool for predicting the levels of myeloma cells in bone marrow, and an additional analysis of FDG uptake of bone marrow on FDG-PET/CT scans should be performed in patients undergoing PET studies during the initial staging, evaluating the therapy response, and monitoring patients with MM.

Radionuclide imaging of bone marrow disorders

Noninvasive imaging techniques have been used in the past for visualization the functional activity of the bone marrow compartment. Imaging with radiolabelled compounds may allow different bone marrow disorders to be distinguished. These imaging techniques, almost all of which use radionuclide-labelled tracers, such as ^99mTc-nanocolloid, ^99mTc-sulphur colloid, ¹¹¹In-chloride, and radiolabelled white blood cells, have been used in nuclear medicine for several decades. With these techniques three separate compartments can be recognized including the reticuloendothelial system, the erythroid compartment and the myeloid compartment. Recent developments in research and the clinical use of PET tracers have made possible the analysis of additional properties such as cellular metabolism and proliferative activity, using ¹⁸F-FDG and ¹⁸F-FLT. These tracers may lead to better quantification and targeting of different cell systems in the bone marrow. In this review the imaging of different bone marrow targets with radionuclides including PET tracers in various bone marrow diseases are discussed.

Time-dependent changes in 18F-FDG activity in the thymus and bone marrow following combination chemotherapy in paediatric patients with lymphoma

PURPOSE

To investigate the time-dependent changes in (18)F-FDG uptake by the thymus and marrow following combination chemotherapy for lymphoma in a paediatric study population.

METHODS

Included in the study were 27 paediatric patients who were in complete metabolic remission after chemotherapy and who underwent off-therapy follow-up with serial whole-body PET-CT scans. A total of 142 PET-CT scans were recorded. (18)F-FDG uptake by the thymus and marrow was assessed both visually and semiquantitatively. Visual uptake was scored on the three-dimensional maximum intensity projection of the whole-body PET image according to a three-point scale. For the semiquantitative assessment, standard uptake values were measured. To find a pattern in the (18)F-FDG uptake by the thymus and marrow a moving average technique was applied.

RESULTS

Our time series analysis indicated that the marrow activity was highest at cessation of chemotherapy and declined thereafter. During an off-chemotherapy period of on average 6 months, marrow activity decreased quickly. From 6 months onward, the activity declined more slowly. The posttherapy changes in (18)F-FDG uptake by the thymus were quite different from the changes in uptake by the marrow. The lowest thymic FDG uptake was found at cessation of chemotherapy. Thereafter, thymic activity steadily increased, reached a peak on average 10 months after therapy, and then slowly decreased.

CONCLUSION

Knowledge of the time-dependent changes in metabolic activity in the thymus and marrow is important to avoid misinterpretation of increased (18)F-FDG uptake as disease in the off-therapy setting.

Correcting tumour SUV for enhanced bone marrow uptake: retrospective 18F-FDG PET/CT studies

PURPOSE

The concentration of F-FDG in the bone marrow is usually low. One common cause of high uptake is due to bone marrow stimulating drugs administered in conjunction with chemotherapy or radiation therapy. It has been hypothesized that the sequestration of F-FDG to the bone marrow may reduce the standardized uptake value (SUV) of a tumour. We tested this hypothesis by quantifying total F-FDG uptake in the bone marrow of patients with visibly enhanced bone marrow uptake and computing its effect on tumour SUV.

METHODS

Total F-FDG in bone marrow was measured in two groups of PET/CT studies: one (n=19) with visibly enhanced bone marrow, the other (n=5), a baseline group with 'normal' levels of uptake. To measure the F-FDG in bone marrow, the entire skeleton in the CT was segmented from surrounding tissue, and the resulting volume applied to the PET image. Using kinetic analysis we show that the predicted correction factor to tumour SUV is given by (1-q0/Q)/(1-q/Q), where Q is the injected dose, and q and q0 are enhanced and baseline bone marrow uptake (MBq).

RESULTS

The enhanced bone marrow uptake averaged 8.9+/-3.2% of injected dose (15.2% max) vs. 4.2+/-0.4% (4.6% max) at baseline. This resulted in a predicted artificial decrease in tumour SUV of up to 11.5% (4.9+/-4.3%, on average).

CONCLUSION

Enhanced bone marrow uptake is predicted to reduce tumour SUVs by as much as 11.5% in our patient group and is a potential confounding factor in using SUV for monitoring tumour response to therapy.

Correlations between 18F-FDG uptake by bone marrow and hematological parameters: measurements by PET/CT

The aim of this study was to investigate the correlations between (18)F-FDG uptake by bone marrow and various hematological parameters. Forty-eight patients who underwent FDG-PET/CT studies and also received hematological examinations within 5 days before or after the PET study were included in this study. All patients had not received chemotherapy. FDG uptake by bone marrow was measured as a standardized uptake value (SUV) on three-dimensional PET/CT fusion images, and the uptake ratio (UR) of the SUV of bone marrow to the SUV of longitudinal dorsal muscle was calculated. The correlations between the SUV and the UR of bone marrow and various hematological parameters were evaluated. Bone marrow FDG uptake was strongly correlated with the white blood cell counts but was not significantly correlated with the red blood cell and platelet counts. The neutrophil count was significantly correlated with bone marrow FDG uptake but the lymphocyte count was not. FDG uptake by bone marrow was specifically correlated with the neutrophil count, suggesting that the FDG uptake by bone marrow reflects marrow metabolism that is mainly regulated by granulocyte progenitors and stimulated by endogenous hematopoietic growth factors. They may also be helpful in interpreting PET images, especially for diagnosing bone marrow involvement by malignancy.

Effect of colony-stimulating factor and conventional- or high-dose chemotherapy on FDG uptake in bone marrow

PURPOSE

Granulocyte or granulocyte-macrophage colony stimulating factor (CSF), usually used in conjunction with chemotherapy, may interfere with the( 18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) reading. The purpose of this study is to evaluate the effects of CSF, conventional-or high-dose chemotherapy on bone marrow FDG uptake.

METHODS

Two hundred and forty-one FDG PET scans obtained in 163 patients with lymphoma and no pathologically and radiologically proven bone marrow involvement were analyzed. The standardized uptake value (SUV) of each patient's spine was measured.

RESULTS

Among patients with no recent history of CSF use, the average SUV in 36 patients with no history of chemotherapy was 1.60+/-0.34, that in 49 patients with a history of conventional-dose chemotherapy was 1.37+/-0.32, and that in 12 patients with a history of high-dose chemotherapy was 1.26+/-0.25 (P=0.008 and 0.002, respectively by Mann-Whitney U test). In 80 patients treated with conventional-dose chemotherapy and CSF, the average SUV after discontinuation of CSF was as follows: 0-7 days, 2.37+/-1.19; 8-14 days: 2.04+/-0.67; 15-21 days: 1.87+/-0.52; 22-30 days: 1.59+/-0.18; 31-90 days: 1.54+/-0.36. In 45 patients treated with high-dose chemotherapy and CSF, no significant increase in bone marrow uptake was seen in most of them.

CONCLUSION

Bone marrow FDG uptake may be increased by CSF treatment and may be decreased by chemotherapy. In patients treated with conventional-dose chemotherapy and CSF, increased marrow uptake will return to the pretreatment value approximately 1 month after discontinuation of CSF.

[Correlation of hematologic parameters with bone marrow and spleen uptake in FDG PET]

OBJECTIVE

To assess the relationship between various hematologic parameters and bone marrow (BM) and splenic uptake of FDG in PET imaging.

MATERIAL AND METHODS

29 patients with Hodgkin's disease (HD) referred for baseline FDG PET imaging before treatment and without evidence of bone marrow (BM) involvement were included in the study. Splenic uptake also was analyzed in 18 patients without splenic involvement. BM and splenic activity were visually graded on a 3 point scale. Activity pattern was classified as homogeneous or heterogeneous. Semi-quantitative analysis was also performed by drawing regions of interest (ROI) over the spine and spleen. ROIs also were drawn over right lung and liver. FDG uptake ratios for the spine and spleen in comparison with the lung and liver were generated. Visual scoring of marrow and splenic uptake, and the various ratios were correlated with hemoglobin (Hb), white blood cell (WBC), and platelet counts, and correlation coefficients were calculated.

RESULTS

In 27/29 patients (93 %) BM and in 18/18 patients (100 %) spleen uptake was diffuse. There was a direct correlation between BM and spleen uptake of FDG with increasing WBC, which was stronger than the inverse correlation seen with Hb (the lower the Hb the greater the uptake). Correlation with platelet counts was weaker.

CONCLUSION

There is a correlation between hematologic parameters such as Hb, WBC and platelet counts and the uptake of FDG in BM and spleen in PET imaging. Knowledge of this correlation should help to better interpret and understand PET imaging.

Iatrogenic artifacts on whole-body F-18 FDG PET imaging

PURPOSE

Whole-body F-18 FDG PET images frequently show artifacts related to medical and surgical interventions. We present some of the common artifact patterns in this atlas article.

MATERIALS AND METHODS

We studied whole-body F-18 FDG PET images of 30 adult patients (17 males and 13 females). Of these, 9 patients had lymphoma, 7 had colon cancer, 6 had lung cancer, 3 had lung nodules, 2 each had breast and bladder cancer, and 1 patient had brain cancer. All patients had a history of some surgical or medical intervention for malignant or some other associated disease.

RESULTS

PET images of 8 patients showed artifacts related to implanted prostheses and ports and 9 patients showed artifacts related to percutaneous insertion or opening of catheters, tubes, and stomas. Six patients had artifacts from previous surgery, 3 from previous radiation therapy, 3 from previous chemotherapy, and 1 from changes in glucose metabolism.

CONCLUSIONS

Medical and surgical interventions can give rise to artifacts on whole-body F-18 FDG PET images. The possibilities and patterns of these artifacts should be kept in mind while reporting these studies.

Molecular imaging in breast cancer

Since the 1960s, bone scanning has played a major role in the management of breast cancer. In the last decade, however, the role of radionuclide molecular imaging has expanded significantly in the clinical management of breast cancer because of fluorodeoxyglucose positron emission tomography, mammoscintigraphy, and sentinel lymph node techniques. Molecular imaging also is instrumental in drug development,gene therapy, and in basic science research of breast cancer. This article provides a comprehensive review of the role of molecular imaging of breast cancer in clinical practice and reports on the current state of research in this field.

Predictive value of early 18F-fluoro-deoxyglucose positron emission tomography in chemosensitive relapsed lymphoma

18F-fluoro-deoxyglucose (FDG) positron emission tomography (PET) might be a better tool than computerized tomography (CT) in predicting long-term treatment outcome in patients with relapsed chemosensitive lymphoma who are candidates for autologous stem cell transplantation (ASCT). We studied patients with recurrent or persistent aggressive non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), who were treated with three courses of second-line induction chemotherapy [DHAP-VIM (dexamethasone, cytarabine, cisplatin followed by etoposide, iphosphamide and methotrexate)-DHAP], followed by myeloablative therapy and ASCT if chemosensitive. FDG-PET was performed in parallel to conventional diagnostic methods before starting, and after two courses of, second-line therapy. Of 68 relapsed lymphoma patients, 46 chemosensitive patients (33 NHL and 13 HD) were included, of whom 39 were transplanted. After DHAP-VIM, the second PET scan was normalized in 15/46 patients; progression-free survival at 2 years was 62% for PET-negative patients versus 32% for PET-positive patients (P = 0.048). The relative risk for progressive disease in patients with < 90% intensity reduction was 2.85 (95% confidence interval 1.15-7.05, P = 0.018). Early FDG-PET may help to predict the long-term treatment outcome of ASCT in chemosensitive patients with relapsed lymphoma and identify those patients who need extra or alternative treatment. Disappearance or > 90% reduction of intensity of abnormal FDG uptake after two courses of reinduction therapy was correlated with a favourable outcome.

Diffusely increased F-18 FDG uptake in bone marrow in a patient with acute anemia and recent erythropoietin therapy

Diffuse uptake of F-18 fluorodeoxyglucose (FDG) by the whole skeleton has been described in case of bone marrow stimulation resulting from treatment with colony-stimulating factors (CSFs): granulocyte CSF or granulocyte-macrophage CSF. The authors describe such an aspect of diffuse FDG uptake by the bone marrow during the follow-up of rectal cancer in a patient with anemia and recently treated thrice weekly by erythropoietin. To their knowledge, such an aspect of diffuse FDG uptake by the skeleton, revealing the bone marrow stimulation by erythropoietin, has not yet been reported.

Interaction of colony-stimulating factors and fluorodeoxyglucose f(18) positron emission tomography

OBJECTIVE

To evaluate reports of altered diagnostic images with fluorodeoxyglucose F(18) (FDG) positron emission tomography (PET) after treatment with colony-stimulating factors (CSFs).

DATA SOURCES

Literature was identified by a MEDLINE search (1966-December 2001). Key search terms included granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor, fluorodeoxyglucose, and emission-computed tomography. English language literature was reviewed.

DATA SYNTHESIS

Reports have suggested altered FDG PET images following CSF treatment. Studies that assessed the effect of CSF administration on FDG PET imaging of the bone and bone marrow were reviewed.

CONCLUSIONS

Administration of CSFs may interfere with accurate FDG PET imaging. Separating FDG PET imaging from CSF therapy by >/=5 days may diminish this interference.

Whole body FDG-PET for the evaluation and staging of small cell lung cancer: a preliminary study

[F18]-2-deoxy-2fluoro-D-glucose positron emission tomography (FDG-PET) is increasingly used in the diagnosis and staging of lung cancer. Despite its positive performance characteristics in non-small cell lung cancer (NSCLC), the role of FDG-PET in the staging of small cell lung cancer (SCLC) remains to be determined. We designed a prospective study to address this question. Eighteen patients with SCLC were enrolled prospectively to undergo total body FDG-PET in addition to conventional staging procedures (chest computed tomography (CT), abdominal CT, cranial CT or magnetic resonance imaging (MRI), and bone scan/bone marrow biopsy). The agreement between FDG-PET and conventional staging modalities in identifying the presence or absence of metastatic disease was compared using the Veterans Administration (VA) cooperative staging system for staging. Overall staging by FDG-PET agreed with conventional staging exams in 15/18 (83%) patients (kappa=0.67), which included eight extensive and seven limited cases. FDG-PET showed more extensive disease in two of the three patients for which FDG-PET and conventional staging disagreed. These data suggest that total body FDG-PET may be useful in the staging, treatment planning, and prognostication of SCLC. Whether FDG-PET will replace other more established staging modalities remains to be determined by larger prospective randomized controlled studies.

Positron emission tomography in the staging of small-cell lung cancer : a preliminary study

STUDY OBJECTIVES

Small-cell lung cancer (SCLC) has an unfavorable prognosis, especially when the disease is extensive at presentation. Accurate staging procedures are therefore needed for treatment planning. Positron emission tomography (PET) is a modern noninvasive imaging technique, the value of which for the staging of SCLC was investigated in the present study.

SETTING

University hospital.

PATIENTS

Thirty-one patients with suspected lung cancer were investigated for staging purposes using chest radiography, CT of the thorax and abdomen, abdominal ultrasound, and bone scanning. Twenty-five patients also received PET examinations during the staging procedures. Five of these patients were found to have SCLC, while two patients had mixed lesion types. Further analysis of the latter group was carried out.

RESULTS

PET detected the primary tumor in all patients, and lymph nodes in five patients. All lymph nodes were proved to be malignant by endoscopic ultrasonography-guided fine-needle aspiration. Only one patient had distant metastases, which were detected by both CT and PET.

CONCLUSIONS

PET appears be a suitable imaging method in SCLC. A potential role for the technique as a standard staging procedure will need to be tested by investigating a larger number of patients in a prospective study.

Hematopoietic cytokine-mediated FDG uptake simulates the appearance of diffuse metastatic disease on whole-body PET imaging

FDG-PET is increasingly being used to assess malignant tumors. However, leukocyte colony-stimulating factors (CSFs), which promote the expansion of hematopoietic bone marrow, have also been demonstrated to cause increased bone-marrow FDG uptake. Three hundred FDG-PET studies conducted over a 1-year period were reviewed for diffuse bone-marrow uptake. Elevated bone-marrow uptake on PET was correlated with pathological findings and courses of granulocyte-CSF (G-CSF) therapy. These results demonstrate that G-CSF mediated FDG uptake in bone marrow is often indistinguishable from that caused by disseminated metastatic disease. However, the bone-marrow response to G-CSF decreases rapidly following the last CSF administration. Therefore, FDG-PET in patients receiving G-CSF should be delayed, when possible, until 5 days after the end of G-CSF therapy.