Usefulness of 18F-FDG PET/CT for the Evaluation of Bone Marrow Involvement in Patients with High-Grade Non-Hodgkin’s Lymphoma

Purpose

To assess the usefulness of ¹⁸F-fluorodeoxyglucose PET/CT in the detection of bone marrow (BM) involvement of high-grade non-Hodgkin’s lymphoma (NHL).

Methods

One hundred twenty patients with newly diagnosed diffuse large B-cell lymphoma or peripheral T-cell lymphoma between January 2007 and June 2011, who received BM trephine biopsy and ¹⁸F-FDG PET/CT before chemotherapy, were included in this retrospective study. We reviewed their ¹⁸F-FDG PET/CT images and bone marrow biopsy (BMB) results. After reviewing the images, we reviewed the medical records and radiological findings of interesting patients.

Results

There were 23 ¹⁸F-FDG PET/CT scans in which the marrow was considered to be abnormal (either positive or equivocal), and 97 ¹⁸F-FDG PET/CT scans were regarded as having negative FDG uptake. Of 120 patients, 100 (83.3 %) had a concordant result of BM interpretation between ¹⁸F-FDG PET/CT and BMB, and the remaining 20 patients had discordant results. Among 23 patients with either positive or equivocal ¹⁸F-FDG PET/CT scans, 1 of 12 patients with ‘positive’ ¹⁸F-FDG PET/CT had a lymphomatous involvement on BMB. In contrast, 10 of 11 patients with ‘equivocal’ BM hypermetabolism were reported as having positive involvement by BMB. Patients with abnormal ¹⁸F-FDG PET/CT had significantly higher mSUV_highest than those with normal FDG-PET/CT.

Conclusions

¹⁸F-FDG PET/CT and BMB are complementary techniques in assessing the presence of BM involvement in patients with high-grade NHL. The increasing availability of ¹⁸F-FDG PET/CT will raise the need for additional biopsy for FDG-avid lesions, especially in patients with negative standard BMBs. ¹⁸F-FDG PET/CT can be useful as a decision-making tool for determining whether to perform a standard BMB or targeted biopsy to the FDG-avid lesion as an initial staging procedure. A direct bone biopsy for FDGpositive bone lesions should be included in staging guidelines in future. In ¹⁸F-FDG PET/CT-negative cases, BMB is still a powerful procedure, but BMB alone is insufficient for full evaluation of BM.     

Findings of fluorine-18-FDG PET in extranodal origin lymphoma —In three cases of diffuse large B cell type lymphoma—

F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is an excellent modality for non-invasive functional imaging of malignant lymphoma and is highly sensitive and specific for the detection of lymphoma lesions. Here, we report the findings of FDG-PET for three cases of diffuse large B cell type lymphoma (DLBCL) with extranodal tumors in the breast, stomach, and liver plus spleen, respectively. The whole body FDG-PET findings showed no evidence of lymph node (LN) involvement or distant metastasis. Strong FDG accumulations were observed in the only extranodal sites by whole body FDG-PET. Therefore, we could confirm that these cases were extranodal primary origins. Whole body PET is useful to determine the primary sites, that is, extranodal origin DLBCL with its clear images.     

FDG PET/CT for the detection of bone marrow involvement in diffuse large B-cell lymphoma: systematic review and meta-analysis

Purpose

To systematically review and meta-analyse published data on the diagnostic performance of ¹⁸F-FDG PET/CT in detecting bone marrow involvement in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL).

Methods

PubMed/MEDLINE and Embase were systematically searched for relevant studies. The methodological quality of each study was assessed. Sensitivities and specificities of FDG PET/CT in individual studies were calculated and meta-analysed with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. Weighted summary proportions of discrepancies between the FDG PET/CT and (blind) bone marrow biopsy (BMB) results among all patients were calculated.

Results

Seven studies, with a total of 654 patients with newly diagnosed DLBCL, were included. Overall, the quality of the included studies was moderate. The sensitivity and specificity of FDG PET/CT for detecting bone marrow involvement ranged from 70.8 % to 95.8 % and from 99.0 % to 100 %, with pooled estimates of 88.7 % (95 % confidence interval, CI, 82.5 – 93.3 %) and 99.8 % (95 % CI 98.8 – 100 %), respectively. The area under the sROC curve was 0.9983. The weighted summary proportion of FDG PET/CT-negative patients with positive BMB findings among all patients was 3.1 % (95 % CI 1.8 – 5.0 %) and the weighted summary proportion of FDG PET/CT-positive patients with negative BMB findings among all patients was 12.5 % (95 % CI 8.4 – 17.3 %).

Conclusion

FDG PET/CT is accurate and complementary to BMB for detecting bone marrow involvement in patients with newly diagnosed DLBCL. A negative FDG PET/CT scan cannot rule out the presence of bone marrow involvement, but positive FDG PET/CT findings obviate the need for BMB for the detection of bone marrow involvement in these patients.     

Spontaneous regression of follicular, mantle cell, and diffuse large B-cell non-Hodgkin's lymphomas detected by FDG-PET imaging

Spontaneous regression of non-Hodgkin lymphoma (NHL) has been reported in low-grade tumors but is an extremely rare event in intermediate- and high-grade disease. Documentation of spontaneous regression by serial fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging has not been reported in the literature. We present 3 cases of spontaneous regression, 1 each of follicular lymphoma (FL), mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL), which showed spontaneous regression on serial FDG-PET imaging. All patients underwent serial whole-body FDG-PET scans 60 minutes after intravenous injection of 9-11 mCi of this radiotracer. None of them had any chemotherapy, radiotherapy, or surgery after the baseline PET scan. Spontaneous regression of disease in all 3 cases was correlated with conventional imaging and clinical course. All 3 patients had positive FDG-PET results on their baseline scan. There was complete disappearance of FDG uptake on a follow-up PET scan for the patient with follicular lymphoma. These results suggest complete regression. The patients with MCL and DLBCL both showed a significant reduction in FDG uptake on serial whole-body PET scans, suggesting partial regression in both cases. Although spontaneous regression of lymphoma is uncommon, this phenomenon can be successfully demonstrated by FDG-PET imaging. Therefore, serial PET imaging may play an important role in detecting this unusual event and may further enhance our understanding of the biologic behavior of this malignancy.     

Clinical impact of whole body FDG-PET on the staging and therapeutic decision making for malignant lymphoma

OBJECTIVES: The aim of this study is to evaluate the clinical impact of whole-body FDG-PET for the pre-therapeutic evaluation of malignant lymphoma and compared to that of 67Ga-scintigraphy when added to non-RI examinations. METHODS: We examined 46 patients with malignant lymphoma including 42 newly diagnosed cases and 4 relapsed cases. Whole-body FDG-PET was started 63 minutes after the administration of FDG with ECAT EXACT HR+. The clinical stage of each patient was determined based on the results of a non-RI examination (consisting of physical examination, CT, gastrointestinal studies and bone marrow aspiration), 67Ga planar images and FDG-PET. Discrepant findings were verified based on the response to treatment and the findings of a follow-up examination more than 6 months after treatment. Finally, 152 nodal regions and 19 extranodal tissues were found to be involved by disease. RESULTS: In the 152 nodal lesions, FDG-PET detected 54 nodal lesions in addition to 98 lesions detected by non-RI examinations, whereas 67Ga-scintigraphy detected 14 additional lesions. The sensitivity of non-RI, non-RI + 67Ga and non-RI + FDG was 64.5%, 73.7% and 100.0%, respectively. In 19 extranodal lesions, FDG-PET detected 5 extranodal lesions in addition to 13 lesions detected by non-RI examinations, whereas 67Ga-scintigraphy detected 1 additional lesion. The sensitivity of non-RI, non-RI + 67Ga and non-RI + FDG was 68.4%, 73.7% and 94.7%, respectively. When combining the FDG-PET findings with the non-RI findings, the improvement of the detectability was much higher than that when 67Ga findings were combined to the non-RI findings. For the staging of lymphoma, the non-RI and non-RI + 67Ga findings accurately diagnosed 76.1% and 80.4%, respectively, whereas the non-RI + FDG findings accurately diagnosed 82.6%. Finally, FDG-PET resulted in changes in the clinical management of 8 patients (17.4%). CONCLUSIONS: FDG-PET offers more information in addition to the findings of conventional diagnostic methods than 67Ga-scintigraphy in order to accurately detect malignant lymphoma. FDG-PET can therefore play an important role in therapeutic decision making on lymphoma.     

A <Superscript>18</Superscript>F-FDG-positive, <Superscript>67</Superscript>Ga-negative,and transferrin receptor expression-negative patient with diffuse large B-cell lymphoma

We recently experienced a case with uveitis suffering from fever of unknown origin suspected of being caused by sarcoidosis. Chest computed tomography showed right supraclavicular, bilateral mediastinal, and right hilar lymphadenopathy, and intensive abnormal uptake of 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) was observed on positron emission tomography with ¹⁸F-FDG (FDG-PET). On the other hand, ⁶⁷Ga scintigraphy showed almost no abnormal findings. Histopathological examination revealed the lesion to be a diffuse large B-cell lymphoma (DLBCL), namely, an aggressive non-Hodgkin lymphoma from a right supraclavicular lymph node biopsy specimen. Additional immunohistochemical analysis showed the negative expression of transferrin receptor (TfR) on the formalin-fixed paraffin-embedded specimen. Although DLBCL is generally considered to be a ⁶⁷Ga-avid tumor, it does not always have a large number of TfRs and that leads to a discrepancy between the ⁶⁷Ga scintigraphy and FDG-PET findings. FDG-PET should be more appropriate for the initial staging of DLBCL than ⁶⁷Ga scintigraphy, whereas ⁶⁷Ga scintigraphy might be able to provide additional information including prognostic factors and to support strategies that target TfR for cancer therapy.     

Characterizing bone marrow involvement in Hodgkin’s lymphoma by FDG-PET/CT

Purpose

Fluoro-deoxyglucose positron emmission tomography combined with computed tomography (FDG-PET/CT) is superior to iliac bone marrow biopsy (iBMB) for detection of bone marrow involvement (BMI) in staging of Hodgkin’s lymphoma (HL). The present study aims to characterize the patterns and distribution of BMI in HL as determined by FDG-PET/CT.

Methods

Reports of FDG-PET/CT studies performed for staging of HL were reviewed. BMI was defined as positive iBMB and/or foci of pathological FDG uptake in the skeleton that behaved in concordance with other sites of lymphoma in studies following chemotherapy. Number of FDG uptake foci, their specific location in the skeleton and the presence of corresponding lesions in the CT component of the study, and stage according to the Ann Arbor staging system, were recorded.

Results

The study included 473 patients. iBMB was performed in 336 patients. Nine patients had positive iBMB (9/336, 3 %). Seventy-three patients (73/473, 15 %) had FDG-PET/CT-defined BMI. The BM was the only extranodal site of HL in 52/473 patients (11 %). Forty-five patients had three or more foci of pathological skeletal FDG uptake (45/73, 62 %). Sixty-four patients (64/73, 88 %) had at least one uptake focus in the pelvis or vertebrae. In 60 patients (60/73, 82 %), the number of skeletal FDG uptake foci without corresponding CT lesions was equal to or higher than the number of foci with morphological abnormalities.

Conclusion

FDG-PET/CT demonstrated BMI in 15 % of patients with newly diagnosed HL. Diagnosis of BMI in HL by FDG-PET/CT was more sensitive than iBMB with potential upstage in 11 % of patients. The most common pattern of FDG-PET/CT BMI was multifocal (at least three foci) skeletal FDG uptake, with at least one focus in the pelvis or vertebrae and no corresponding CT lesions.     

Tumor Burden Assessed by the Maximum Standardized Uptake Value and Greatest Diameter on FDG-PET Predicts Prognosis in Untreated Diffuse Large B-cell Lymphoma

Purpose

It is uncertain whether the tumor burden as assessed using FDG-PET has prognostic significance in newly diagnosed diffuse large B-cell lymphoma (DLBCL). The authors undertook this study to determine whether a parameter that reflects both FDG uptake magnitude and the greatest tumor diameter is a prognostic indicator in DLBCL.

Materials and Methods

Forty-two DLBCL patients (age, 57.4 ± 15.5 years; male/female = 25/17; stage I/II/III/IV=5/17/10/10) who underwent FDG-PET before chemotherapy were enrolled. A lesion with the highest maximum standardized uptake value (MaxSUV) on the PET image was selected, and size-incorporated MaxSUV (SIMaxSUV) of mass was calculated as MaxSUV × greatest diameter (mm) on the transaxial PET image. Median follow-up duration was 20.0 months.

Results

Twelve (28.6% = 12/42) patients experienced disease progression, and 10 (23.8% = 10/42) died during follow-up. Among six variables [Ann Arbor stage, %Ki-67 expression, International Prognostic Index (IPI), MaxSUV, greatest diameter, and SIMaxSUV] investigated, only SIMaxSUV was found to be a single determinant of progression-free and overall survivals by multivariate analyses (p < 0.05).

Conclusion

These results suggest that SIMaxSUV, a new FDG-PET parameter that incorporates FDG uptake magnitude and the greatest tumor diameter, may be a useful indicator of prognosis in untreated DLBCL.     

Differential FDG accumulation associated with GLUT-1 expression in a patient with lymphoma

We herein report a case of malignant lymphoma that showed differential FDG accumulation associated with the degree of glucose transporter 1 (GLUT-1) expression. For clinical staging purpose, FDG-PET was performed on a 47-year-old male who had been diagnosed to have malignant lymphoma, diffuse medium B-cell type. Although an X-ray CT showed multiple and bulky lymphadenopathy including bilateral submandibular, deep cervical, supraclavicular, axillar, hilar, mesenteric and paraaortic regions, FDG-PET showed a high accumulation only in the bilateral submandibular and deep cervical region. An immunohistochemical analysis demonstrated a high GLUT-1 expression in the right cervical lymph node, which showed a high FDG uptake. On the other hand, a bone marrow specimen with diffuse lymphoma cell involvement indicated showed no FDG accumulation and also revealed a negative GLUT-1 expression. This case suggests that the differential FDG accumulation shown by lesions is associated with the degree of GLUT-1 expression in patients with lymphoma.     

Biopsy versus FDG PET/CT in the initial evaluation of bone marrow involvement in pediatric lymphoma patients

Purpose  

The objective is to assess the role of ¹⁸F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/CT versus bone marrow biopsy (BMB) in the initial evaluation of bone marrow (BM) involvement in pediatric lymphoma patients.     

Whole-body MRI for the detection of bone marrow involvement in lymphoma: prospective study in 116 patients and comparison with FDG-PET

Objective

To assess and compare the value of whole-body MRI with FDG-PET for detecting bone marrow involvement in lymphoma.

Methods

A total of 116 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and blind bone marrow biopsy (BMB) of the posterior iliac crest. Of 116 patients, 80 also underwent FDG-PET. Patient-based sensitivities of whole-body MRI for detecting bone marrow involvement were calculated using BMB as reference standard and compared with FDG-PET in aggressive and indolent lymphomas separately.

Results

Sensitivity of whole-body MRI in all lymphomas was 45.5 % [95 % confidence interval (CI): 29.8–62.0 %]. Sensitivity of whole-body MRI in aggressive lymphoma [88.9 % (95 % CI: 54.3–100 %)] was significantly higher (P?=?0.0029) than that in indolent lymphoma [23.5 % (95 % CI: 9.1–47.8 %)]. Sensitivity of FDG-PET in aggressive lymphoma [83.3 % (95 % CI: 41.8–98.9 %)] was also significantly higher (P?=?0.026) than that in indolent lymphoma [12.5 % (95 % CI: 0–49.2 %)]. There were no significant differences in sensitivity between whole-body MRI and FDG-PET (P?=?1.00)

Conclusion

Sensitivity of whole-body MRI for detecting lymphomatous bone marrow involvement is too low to (partially) replace BMB. Sensitivity of whole-body MRI is significantly higher in aggressive lymphoma than in indolent lymphoma and is equal to FDG-PET in both entities.

Key Points

? Bone marrow involvement in lymphoma has prognostic and therapeutic implications. ? Blind bone marrow biopsy (BMB) is standard for bone marrow assessment. ? Neither whole-body MRI nor FDG-PET can yet replace BMB. ? Both techniques have higher sensitivity in aggressive than in indolent lymphoma. ? Both imaging techniques are complementary to BMB.     

Dual-phase 18F-fluoro-2-deoxy-d-glucose positron emission tomography as a prognostic parameter in patients with pancreatic cancer

Purpose Recently, dual-phase ¹⁸F-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) was shown to be useful in the differentiation between malignant and benign pancreatic lesions. The aim of this prospective study was to evaluate the value of dual-phase FDG-PET as a prognostic parameter in patients with pancreatic cancer.Methods Sixty-five consecutive patients with pancreatic cancer underwent dual-phase FDG-PET. Standardised uptake values at 1 h (SUV1) and 2 h (SUV2) following the injection of FDG were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1. The prognostic value of SUV1, SUV2 and RI was analysed, along with the various clinical and biochemical parameters.Results Multivariate analysis showed that only three factors had an independent association with longer patient survival: female gender (p<0.01), TNM stage I–III (p<0.05) and RI>10% (p<0.01). Neither SUV1 nor SUV2 showed any prognostic significance. Combination of tumour stage and RI allowed more accurate prognostic evaluation. Patients at stage I–III with RI>10% survived longer than did patients at the same stage with RI<10% (15.3 vs 11.5 months, p<0.01). Patients at stage IV with RI>10% had an intermediate prognosis, with a median survival of 9.5 months; patients at stage IV with RI<10% showed the worst prognosis, with a median survival of 4.9 months (p<0.05).Conclusion RI calculated with dual-phase FDG-PET can be used not only as a tool for initial diagnosis and staging of pancreatic cancer but also as a strong independent prognostic parameter that can allow accurate identification of those patients who will benefit from intensive anticancer treatment at different stages of the disease.     

18FDG uptake associated with CT density on PET/CT in lungs with and without chronic interstitial lung diseases

Objective  The dependent-density of computed tomography (CT) images of positron emission tomography (PET)/CT is sometimes difficult to distinguish from chronic interstitial lung disease (ILD) when it accompanies increased ¹⁸F-fluorodeoxy-d-glucose (¹⁸FDG) uptake. Though the possible utility of ¹⁸FDG-PET for the diagnosis of active ILD has been reported, the clinical relevance of mild lung ¹⁸FDG uptake in ILD cases without signs and symptoms suggesting acute progression has not been described. This study aimed to test relationships between ¹⁸FDG uptake and lung density on CT using PET/CT in patients with normal lung as well as clinically stable chronic ILD. Methods  Thirty-six patients with normal lungs (controls) and 28 patients with chronic ILD (ILD cases) without acute exacerbation were retrospectively selected from ¹⁸FDG-PET/CT scans performed in examination of malignant neoplasms. Elliptical regions of interest (ROIs) were placed on the lung. The relationships between CT density and ¹⁸FDG uptake between the control and ILD cases were tested. Results  The CT density and ¹⁸FDG uptake had a linear correlation in both the controls and the ILD cases without a difference in their regression slopes, and they were overlapped between the controls and the ILD cases with higher mean values in the ILD cases. Conclusions  Lung ¹⁸FDG uptake was considered to reflect a gravity-dependent tissue density in the normal lung. Though the lung ¹⁸FDG uptake as well as the CT density tended to be higher in chronic ILD patients, it may be difficult to distinguish them in normal dependent regions from those related to chronic ILD in some cases.     

Bone involvement in patients with lymphoma: the role of FDG-PET/CT

Purpose To evaluate the diagnostic impact and clinical significance of FDG-avid bone lesions detected by FDG-PET/CT in patients with lymphoma. Methods The study population comprised 50 consecutive patients (mean age 41.7±15.5 years; 27 female, 23 male; 41 staging, 9 restaging) with Hodgkin’s disease (n=22) or aggressive non-Hodgkin’s lymphoma (n=28) in whom FDG-avid bone lesions were detected by FDG-PET/CT. All patients had either direct biopsy of the FDG-avid bone lesion (n=18), standard bone marrow biopsy at the iliac crest (BMB; n=43) or both procedures (n=11). In 15 patients, additional MRI of the bone lesions was performed. All patients underwent FDG-PET/CT after the end of treatment. All CT images of FDG-PET/CT scans were analysed independently regarding morphological osseous changes and compared with FDG-PET results. Results In the 50 patients, 193 FDG-avid lesions were found by PET/CT. The mean standardised uptake value was 6.26 (±3.22). All direct bone biopsies (n=18) of the FDG-avid lesions proved the presence of lymphomatous infiltration. BMB (n=43) was positive in 12 patients (27.9%). In CT, 32 of 193 (16.6%) lesions were detected without the PET information. No additional morphological bone infiltration was detected on CT compared with FDG-PET. All morphological bone alterations on CT scans persisted after the end of therapy. Additional PET/CT information regarding uni- or multifocal bone involvement resulted in lymphoma upstaging in 21 (42%) patients compared with the combined information provided by CT and BMB. Conclusion In patients with FDG-avid bone lesions, FDG-PET is superior to CT alone or in combination with unilateral BMB in detecting bone marrow involvement, leading to upstaging in a relevant proportion of patients.     

Usefulness of FDG PET for diagnosis and radiotherapy of the patient with malignant lymphoma involving bone marrow

We experienced a case of relapsed malignant lymphoma with multiple bone marrow or bone lesions. The case was diagnosed as follicular lymphoma by cytological biopsy of the right iliac bone, with ⁶⁷Ga scintigraphy showing abnormal, intense uptake in multiple bones. After about 10 months of systemic chemotherapy, a relapse was suspected because of pain in the bilateral legs and a high level of lactate dehydrogenase. Assessment of the lesions in the patient was difficult by computed tomography because the affected sites were localized mainly in the bone marrow. ¹⁸F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) was useful for detecting accurately the relapse sites in the bone marrow and enabled us to determine the field for radiotherapy. There are only a few reports of FDG-PET findings for such bone marrow malignant lymphomas. Therefore, we report the findings of FDG-PET for this case and review some of the literature about bone marrow lymphomas.     

Clinical significance of 18F-FDG uptake by primary sites in patients with diffuse large B cell lymphoma in the head and neck: a pilot study

Objective  This pilot study was launched to explore the utility of positron emission tomography scans, at the time of diagnosis, for clinical outcomes in patients with primary extranodal non-Hodgkin’s lymphoma (PENHL) in the head and neck, retrospectively. Methods  Twenty-two patients with a diffuse large B cell lymphoma (DLBCL) among those with a PENHL were included. We retrospectively evaluated the clinical outcomes of patients according to the maximum standardized ¹⁸F-fluoro-2-deoxy-glucose (¹⁸F-FDG) uptake value of the primary lesion (SUV_p). The SUV_p was initially analyzed as a continuous variable. The cut-offvalue of SUV_p was obtained from receiver-operating characteristic analysis to predict event-free survival. Using this value, patients were divided into those with a low and high SUV. Results  Seventeen patients (59%) were men and the median age was 50 years. Most primary sites were in Waldeyer’s ring (73%). The SUV_p ranged from 3.3 to 23.7. The international prognostic index (IPI < 2 vs. ≥ 2) was associated with the SUV_p (P = 0.014). Patients with low SUV_p showed favorable survival (P = 0.015). After IPI scores were stratified, the survival difference remained significant (P = 0.029). Conclusions  The results of this pilot investigation indicate that ¹⁸F-FDG uptake of the primary lesion may be related with survival outcomes in patients with extranodal DLBCL in the head and neck. Further studies are needed to confirm and extend these results. I.I. Na and G.J. Cheon contributed equally to this work.     

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 ¹⁸F-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.     

Post transplant lymphoproliferative disease in pediatric solid organ transplant patients: a possible role for [18F]-FDG-PET(/CT) in initial staging and therapy monitoring

Post transplant lymphoproliferative disease (PTLD) is a severe complication after solid organ or bone marrow transplantation. In pediatric transplant recipients PTLD is the most common malignancy. The aim of this study was to evaluate a possible role for positron emission tomography with [18F]-2-fluoro-2-desoxy-glucose (FDG) in the initial staging and in therapy monitoring of pediatric patients suffering from biopsy-proven CD20-positive PTLD after solid organ transplantation. Seven pediatric patients were included. All available imaging studies - CT (n=15), MRI (n=16) and PET/PETCT (n=16) - were reviewed on a lesion by lesion base. The performance of FDG-PET in the initial staging and during therapy with a chimeric anti-CD20 antibody was compared to conventional cross sectional imaging and correlated with the clinical outcome. FDG-PET identified all sites of disease as shown by CT/MRI and helped to clarify the significance of equivocal findings. The initial stage of disease was correctly identified by FDG-PET alone when compared to CT/MRI. During therapy, FDG-PET was superior to conventional cross-sectional imaging in the early evaluation of response.     

Mucosa-associated lymphoid tissue lymphoma studied with FDG-PET: a comparison with CT and endoscopic findings

OBJECTIVE: We investigated the accumulation of 2-deoxy-2-[(18)F] fluoro-D: -glucose positron emission tomography (FDG-PET) in patients with mucosa-associated lymphoid tissue (MALT) lymphoma patients as compared with computerized tomography (CT) and endoscopic imaging. METHODS: FDG-PET was performed on 13 untreated patients with MALT lymphoma. CT scanning of the affected areas was performed in all the patients to compare with the FDG-PET images. In five patients with gastric MALT lymphoma, comparison was also made with the endoscopic findings. RESULTS: Of the 13 untreated MALT lymphoma patients, all 8 non-gastric MALT lymphoma patients exhibited abnormal accumulation of FDG. However, in the five gastric MALT lymphoma patients, no abnormal FDG accumulation was observed. Although lesions could be confirmed on CT images from the patients other than those with gastric MALT lymphoma, the mucosal lesions of gastric MALT lymphoma could be observed only by endoscopy. CONCLUSIONS: FDG-PET can be used to detect MALT lymphoma when it forms mass lesions, whereas it is difficult to detect non-massive MALT lymphoma of gastrointestinal origin.     

From tumor biology to clinical PET: A review of positron emission tomography (PET) in oncology

Cancer cells show increased metabolism of both glucose and amino acids, which can be monitored with 18F-2-deoxy-2-fluoro-D-glucose (FDG), a glucose analogue, and 11C-L-methionine (Met), respectively. FDG uptake is higher in fast-growing than in slow-growing tumors. FDG uptake is considered to be a good marker of the grade of malignancy. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as a prognostic indicator. Differential diagnosis of lung tumors has been studied extensively with both computed tomography (CT) and positron emission tomography (PET). It has been established that FDG-PET is clinically very useful and that its diagnostic accuracy is higher than that of CT. Detection of lymph node or distant metastases in known cancer patients using a whole-body imaging technique with FDG-PET has become a good indication for PET. FDG uptake may be seen in a variety of tissues due to physiological glucose consumption. Also FDG uptake is not specific for cancer. Various types of active inflammation showed FDG uptake to a certain high level. Understanding of the physiological and benign causes of FDG uptake is important for accurate interpretation of FDG-PET. In monitoring radio/chemotherapy, changes in FDG uptake correlate with the number of viable cancer cells, whereas Met is a marker of proliferation. Reduction of FDG uptake is a sensitive marker of viable tissue, preceding necrotic extension and volumetric shrinkage. FDG-PET is useful for the detection of recurrence and for monitoring the therapeutic response of tumor tissues in various cancers, including those of the lung, colon, and head and neck. Thus, PET, particularly with FDG, is effective in monitoring cancer cell viability, and is clinically very useful for the diagnosis and detection of recurrence of lung and other cancers.