18p-FDG PET is superior to67Ga SPECT in the staging of non-Hodgkin’s lymphoma

Maximum standardized uptake value in 11C-methionine positron emission tomography may predict the prognosis of patients with oral squamous cell carcinoma

The present study aimed to elucidate the correlation between the uptake of 11C-methionine (MET) by a primary tumor and the survival of patients with oral squamous cell carcinoma (OSCC). This study enrolled 31 patients who underwent radical surgery for OSCC. The patients underwent pretreatment MET-positron emission tomography (PET) scanning. We analyzed correlations between the maximum standardized uptake value (SUVmax) of MET-PET in a primary tumor and the clinicopathological features. Further, we compared overall survival (OS), disease-specific survival (DSS), and loco-regional recurrence (LRR) rates between the two groups according to SUVmax of MET-PET. SUVmax of MET-PET in a primary tumor was higher in patients with advanced T-classification and advanced clinical stage, with significant differences (P = 0.001 and P = 0.016, respectively). The patients with SUVmax of MET-PET ≥ 4.4 showed significantly lower DSS rates and higher LRR rates than those with SUVmax of < 4.4 (P = 0.015 and P = 0.016, respectively). SUVmax of MET-PET and OS rates showed no significant correlation (P = 0.073). The present study revealed that SUVmax of MET-PET may predict clinical outcomes and prognosis in patients with OSCC who underwent radical surgery.

Role of Artificial Intelligence in PET/CT Imaging for Management of Lymphoma

Our review shows that AI-based analysis of lymphoma whole-body FDG-PET/CT can inform all phases of clinical management including staging, prognostication, treatment planning, and treatment response evaluation. We highlight advancements in the role of neural networks for performing automated image segmentation to calculate PET-based imaging biomarkers such as the total metabolic tumor volume (TMTV). AI-based image segmentation methods are at levels where they can be semi-automatically implemented with minimal human inputs and nearing the level of a second-opinion radiologist. Advances in automated segmentation methods are particularly apparent in the discrimination of lymphomatous vs non-lymphomatous FDG-avid regions, which carries through to automated staging. Automated TMTV calculators, in addition to automated calculation of measures such as Dmax are informing robust models of progression-free survival which can then feed into improved treatment planning.

The Evolving Role of Medical Imaging in Lymphoma Management: The Clinician's Perspective

Hodgkin and non-Hodgkin lymphomas are a heterogeneous group of hematologic neoplasms which arise from malignant lymphocytes. Imaging plays an important role in management of lymphoma patients during diagnosis, staging, and response assessment. Functional imaging may also provide prognostic information and improve the ability to detect extranodal disease. This article provides an overview of the evolving role of various imaging techniques in lymphoma from the clinician's perspective. It serves as an introduction to the other articles in this issue that focus on specific areas of lymphoma imaging.

[Quantitative and qualitative evaluation of the interim PET/CT in lymphoma treatment in the prediction of complete metabolic response]

OBJECTIVE

To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et).

MATERIAL AND METHODS

Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria.

RESULTS

We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942).

CONCLUSION

We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study.

Impact of FDG-PET/CT in the management of lymphoma

Since the introduction of (67)Gallium-citrate 30 years ago, nuclear medicine has played an important role in the evaluation of malignant lymphoma. During that time, several radiotracers were evaluated as potential alternatives for the diagnosis of lymphoma, but the introduction of (18)F-fluorodeoxyglucose PET (FDG-PET) marked a major turning point. FDG-PET took over most of the role of gallium, and is now an essential tool in the diagnosis of lymphoma. FDG-PET is increasingly being used for assessment of the tumor staging prior to treatment, for evaluating the response to treatment, and for monitoring the early reactions to therapy to predict the final outcome. FDG-PET has been shown to have more accurate diagnostic capability than conventional CT and MRI for distinguishing the tumor necrosis and residual masses frequently seen after therapy in lymphoma patients without any clinical and biochemical manifestation. Malignant lymphoma is the first disease for which FDG-PET was adopted as a tool for response assessment in the international standard criteria. However, lymphoma does not always display a clear high uptake, and there are some pitfalls in assessing the response to therapy. This review will highlight the most important applications of FDG-PET in lymphoma, focusing on the advantages and pitfalls of this imaging, and past and ongoing efforts to standardize the use of FDG-PET, particularly in response to assessment and therapy monitoring.

Underperformance of gallium-67 scan is greater in relapse than in initial staging, compared with FDG PET

PURPOSE

The purpose of this study is to evaluate the performance of gallium-67 scan (GS) and F-18 fluorodeoxyglucose (FDG) PET scan in lymphoma staging and recurrence detection by comparing the 2 imaging studies in the same patient.

MATERIALS AND METHODS

A total of 42 patients from the period between July 2002 and May 2006 were included in this study. Of the 42 patients, 6 had Hodgkin disease and 36 had non-Hodgkin lymphomas. All of them underwent one or more FDG PET scans and also underwent corresponding GS performed within 7 days of FDG PET, for staging or detection of lymphoma recurrence. Among the non-Hodgkin lymphoma cases, 18 were diffuse large B-cell lymphoma, 10 were follicular center cell lymphoma, and 8 were of other types. Of the total 46 pairs of imaging performed in these 42 patients, 27 were for staging, and 19 for restaging after recurrence.

RESULTS

In all these studies, FDG PET detected 230 lesion sites, whereas GS detected 85 lesion sites. All of the lesions detected by GS were noted on FDG PET, whereas GS detected only 37.0% of the lesions detected by FDG PET. Among the 27 studies for staging, FDG PET detected 120 lesions, whereas GS detected 68 lesions (56.7%). In the 19 images taken for relapse, FDG PET detected 110 lesions, whereas GS detected only 17 (15.5%).

CONCLUSIONS

FDG PET is superior to GS in staging and detecting all types of lymphoma. The difference is notably more significant in recurrence detection.

PET imaging in lymphoma

PET has become a cornerstone procedure in modern lymphoma management. This paper reviews, from a clinical point of view, the evidence for using PET in the different subtypes of lymphoma and the different steps of their management. The reader is given an overview of the current PET-based interventional lymphoma trials and an insight into possible future developments in the field, including new PET tracers.

Imaging of pediatric lymphomas

Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) represent 10% to 15% of all malignancies occurring in children younger than 20 years of age. Advances in cross-sectional imaging and the availability of positron emission tomography (PET) and PET-CT have had a major impact on imaging and management of pediatric patients. This article reviews the clinical features of lymphoma, focusing on the spectrum of imaging findings seen in diagnosis, staging, and follow-up of HL and NHL. Pediatric NHL has four major histologic subtypes: Burkitt lymphoma, diffuse large B-cell lymphoma, anaplastic large cell lymphoma, and lymphoblastic lymphoma. The most important subtype of HL is nodular sclerosis.

Prognostic impact of pre-transplantation computed tomography and 67gallium scanning in chemosensitive diffuse large B cell lymphoma patients undergoing hematopoietic stem-cell transplantation

OBJECTIVE

In the present study, we evaluated computed tomography (CT) and (67)gallium scanning ((67)Ga scan) pre-transplant as prognostic factors for overall survival (OS) and event-free survival (EFS) in patients with diffuse large B cell lymphoma, undergoing high-dose chemotherapy and stem-cell transplantation.

PATIENTS AND METHODS

Forty-two patients were included. Of these, 9 (21%) had both positive CT and (67)Ga scans, 17 (41%) negative results with both techniques, and 16 (38%) positive CT/negative (67)Ga scan. Whole-body planar imaging and single-photon emission computed tomography (SPECT) were performed 72 h after an intravenous administration of (67)Ga citrate measuring between 7 mCi and 10 mCi (259-370 MBq).

RESULTS

Patients with positive CT/positive (67)Ga scan had a significantly worse EFS and OS at 5 years than those with negative (67)Ga scan regardless of whether it was associated with a positive or a negative CT scan (29% and 16% vs. 81% and 93% vs. 88% and 100%, respectively, P < 0.001). After a median follow-up of 43 months (range 4-130 months), no differences were observed between patients with negative CT/negative (67)Ga scan and those with positive CT/negative (67)Ga scan, with an EFS and OS at 5 years of 88% versus 81% and 100% versus 93%, respectively. In multivariate analysis, the presence of a pre-transplant positive CT/(67)Ga scans adversely influenced both EFS and OS [HR 8, 95% confidence interval (CI) (1.4-38), P = 0.03 and HR 2; 95% CI (1.3-8), P = 0.02, respectively].

CONCLUSIONS

(67)Ga scan helps to identify, in the pre-transplant evaluation, two groups with a different outcome: one group of patients with positive CT and negative (67)Ga scans pre-transplant, who showed a favorable outcome with a low rate of relapse, and the other group of patients with both positive CT and (67)Ga scans pre-transplant, who showed a poor prognosis and did not benefit from autologous stem-cell transplantation. They should have been offered other therapeutic strategies.

Cross-sectional imaging of extranodal involvement in abdominopelvic lymphoproliferative malignancies

Extranodal lymphoproliferative diseases are common, and their prevalence is increasing. Non-Hodgkin lymphomas and Hodgkin disease, in particular, frequently involve extranodal structures in the abdomen and pelvis, including both the solid organs (liver, spleen, kidneys, and pancreas) and the hollow organs of the gastrointestinal tract. Because virtually any abdominopelvic tissue may be involved, many different imaging manifestations are possible, and lymphoproliferative diseases may mimic other disorders. Familiarity with the imaging manifestations that are diagnostically specific for extranodal lymphoproliferative diseases is important because imaging plays an important role in the noninvasive management of disease. However, a definitive diagnosis requires a biopsy (of bone marrow, a lymph node, or a mass), a peripheral blood analysis, and other laboratory tests. In patients with known disease, the goals of imaging are staging, evaluation of response to therapy, and identification of new or recurrent disease or of complications of therapy. In patients without known disease, imaging permits a provisional diagnosis.

2-[18F]fluoro-2-deoxyglucose positron-emission tomography in staging, response evaluation, and treatment planning of lymphomas

2-[18F]fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) is used increasingly in the clinical management of lymphomas. With regard to staging, FDG-PET is more sensitive and specific than conventional staging methods in FDG avid lymphomas (ie, Hodgkin lymphoma and most aggressive non-Hodgkin lymphomas). Despite methodological problems, in particular the lack of a valid reference test, FDG-PET is approved and generally used for this purpose. With regard to response evaluation, FDG-PET at the end of treatment seems to aid considerably in differentiating between residual masses with or without residual lymphoma. Hence, new revised response criteria have been proposed, incorporating the result of FDG-PET at the end of treatment. An early interim FDG-PET scan after 1 to 3 cycles of chemotherapy is a very strong predictor of outcome, and trials are now in progress testing treatment modifications on this basis. With regard to treatment planning, in the context of combined-modality therapy, radiotherapy for lymphomas is moving toward more conformal techniques reducing the irradiated volume to include only the macroscopic lymphoma. In this situation, accurate imaging is essential, and FDG-PET coregistered with the planning computed tomography (CT) scan is used increasingly. The availability of PET/CT scanners suited for virtual simulation has aided this process. However, clinical data evaluating this technique are at present sparse.

Comparison of MET-PET and FDG-PET for differentiation between benign lesions and lung cancer in pneumoconiosis

OBJECTIVE

The aim of this study was to evaluate and compare the ability of C-11-methionine (MET) and F-18 fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) to diagnose lung cancer in patients with pneumoconiosis.

METHODS

Twenty-six subjects underwent both whole-body MET-PET and FDG-PET on the same day. The first group was a lung cancer group, which consisted of 15 patients, and included those with pneumoconiosis with increased nodules (13 cases), hemoptysis (1 case), and positive sputum cytology (1 case). The second group was a no-malignancy control group, consisting of 11 patients with pneumoconiosis.

RESULTS

Significant correlations between nodule size and the maximum standardized uptake value (SUV(max)) of the two PET tracers were observed in the control group. The larger the nodule size, the greater were the amounts of these tracers accumulated (MET: r = 0.771, P < 0.0001; FDG: r = 0.903, P < 0.0001). The SUV(max) of MET was significantly lower than that of FDG in the pneumoconiotic nodules (P < 0.0001). Lung cancer was found in 5 of 19 nodules (two with adenocarcinoma, one with squamous cell carcinoma, one with small cell carcinoma, and one with large cell carcinoma) in the first group. As for nodules equal to or less than 3 cm in diameter, the SUV(max) of MET was significantly higher in the lung cancer than in the pneumoconiotic nodules, with 3.48 +/- 1.18 (mean +/- SE) for the lung cancer and 1.48 +/- 0.08 for the pneumoconiotic nodules (P < 0.01), similar to the SUV(max) of FDG, with 7.12 +/- 2.36 and 2.85 +/- 0.24 (P < 0.05), respectively. On the basis of the criteria for the control group, FDG and MET identified lung cancer with sensitivities of 60% and 80%, specificities of 100% and 93%, accuracies of 90% and 90%, positive predictive values of 100% and 80%, and negative predictive values of 88% and 93%, respectively.

CONCLUSIONS

Our results indicate that nodules with an intense uptake of MET and FDG relative to their size should be carefully observed because of a high risk for lung cancer.

Positron emission tomography imaging for lymphoma

PURPOSE OF REVIEW

To review the current role and the limitations of F-fluorodeoxygenase positron emission tomography in the management of lymphoma, with a particular focus on studies published since January 2004.

RECENT FINDINGS

F-fluorodeoxygenase positron emission tomography should be routinely performed at the initial diagnosis of patients with suffering from Hodgkin's disease because it adds useful informations to conventional staging techniques. Residual F-fluorodeoxygenase uptake is an important prognostic factor after one or a few cycles of chemotherapy, but it is clearly too early to change patient treatment on the basis of F-fluorodeoxygenase positron emission tomography results. F-fluorodeoxygenase positron emission tomography is the best noninvasive imaging technique after treatment; however, it is always indicated to correlate positron emission tomography findings with clinical data, other imaging modalities, a biopsy, or all three to reduce the risk of false positive results. There are some concerns about the positive predictive value of positron emission tomography after treatment, especially in childhood lymphoma. Clinicians should be aware of positron emission tomography findings in specific clinical conditions in this patient population. F-fluorodeoxygenase positron emission tomography combined with computed tomography offers advantages over the two used separately and read side by side. It may be particularly useful for the planning of radiation therapy or for the planning of a surgical biopsy. Several studies have shown that F-fluorodeoxygenase positron emission tomography is definitively superior to Ga scintigraphy. New radiotracers such as F-fluorothymidine may be useful for the noninvasive assessment of proliferation in vivo.

SUMMARY

F-fluorodeoxygenase positron emission tomography has become the most important nuclear medicine imaging modality in the field of lymphoma. It should be routinely used in the treatment of lymphoma patients.

PET/CT today: System and its impact on cancer diagnosis

Over the past six years, PET/CT has spread rapidly and replaced conventional PET. Although PET/CT is a combination of PET for functional information and CT for morphological information, their combination is synergistic. PET/CT fusion images result in higher diagnostic accuracy with fewer equivocal findings. This results in a greater impact on cancer diagnosis. With attenuation correction performed by the CT component, PET/CT can provide higher quality images over shorter examination times than conventional PET. As with all modalities, PET/CT has several characteristic artifacts such as misregistration due to respiration, overattenuation correction due to metals, etc. Awareness of these pitfalls will help the imaging physician use PET/CT effectively in daily practice.

Detection of aortic graft infection by fluorodeoxyglucose positron emission tomography: Comparison with computed tomographic findings

OBJECTIVE

Radionuclide imaging with fluorodeoxyglucose (FDG) and positron emission tomography (PET) has been proposed for the identification of vascular graft infection; however, its accuracy has not been determined. We performed this prospective study to compare the usefulness of FDG-PET in the assessment of vascular graft infection relative to computed tomography (CT).

METHODS

FDG-PET was performed for 33 consecutive patients with a suspected arterial prosthetic graft infection. The PET images were then assessed visually in terms of the density of uptake. In cases with positive uptake, the pattern of accumulation was also defined, such as focal or diffuse uptake. We compared the diagnostic efficiency of PET with contemporaneous CT in detection of infection of the arterial prosthetic graft.

RESULTS

On the basis of the surgical, microbiological, and clinical follow-up findings, the aortic grafts were considered infected in 11 patients and not infected in 22 patients. Although the sensitivity of PET (91%) was higher than that of CT (64%), its specificity (64%) was lower than that of CT (86%). When focal uptake was set as the positive criterion in FDG, the specificity and positive predictive value of PET for the diagnosis of aortic graft infection improved significantly to 95% (P < .05 for both).

CONCLUSIONS

Although both techniques are useful in evaluation of patients with suspected aortic graft infection, using the characteristic FDG uptake pattern described previously as a diagnostic criterion made the efficacy of FDG superior to that of CT in the diagnostic assessment of patients with suspected aortic graft infection.