fluoro-D-glucose Positron Emission Tomography/computed Tomography Research Articles

OGC P01 Evaluating the use of FDG PET-CT for restaging patients with oesophageal adenocarcinoma treated with neoadjuvant chemotherapy

Abstract Background 2-deoxy-2[18F]fluoro-D-glucose positron emission tomography-computed tomography (FDG-PET-CT) is routinely used for staging oesophageal cancer and has an emerging role in evaluating response to neoadjuvant chemotherapy (NACT). This study aimed to evaluate the clinical utility of FDG-PET-CT and contrast-enhanced CT (CECT) in restaging patients with oesophageal adenocarcinoma treated with NACT. The accuracy for evaluating depth of tumour invasion (ypT stage), pathological nodal disease (ypN stage) and identifying distant metastases compared with CECT was assessed. The ability of FDG-PET-CT to predict pathological response in the primary tumour (pTR) and LNs (pNR) was also evaluated. Methods Cohort study of 104 patients with locally advanced oesophageal or oesophago-gastric junctional adenocarcinoma who underwent FDG-PET-CT and CECT before and after NACT at Guy’s and St Thomas’ NHS Foundation Trust, London, UK, between 2017–2020. SUV metrics related to the primary tumour and loco-regional LNs were derived on pre- and post- treatment FDG-PET-CT. pTR and pNR were evaluated using the Mandard classification. Receiver operator characteristic analysis was performed and area under the curve (AUC) calculated to evaluate the discriminatory ability of FDG-PET-CT and CECT to predict ypT3-4 or pN positive disease. Clinicopathological characteristics were compared using the Chi-squared test. Results 91/104 patients underwent surgical resection following NACT. Four patients (3.8%) had metastatic disease identified on FDG-PET-CT only. None had metastatic disease identified on CECT only. The ability of FDG-PET-CT and CECT to predict ypT stage was comparable. However, FDG-PET-CT demonstrated better discriminatory ability (FDG-PET-CT; AUC 0.71, CECT; AUC 0.62, p=0.210). FDG-PET-CT was more accurate for ypT0-2 tumours (p=0.022), whilst CECT was superior for ypT3-4 tumours (p=0.002). The ability of both modalities to predict ypN1-3 disease was poor (FDG-PET-CT; AUC 0.55, CECT; AUC 0.53, p=1.00). Metabolic response on FDG-PET-CT was predictive of pTR (AUC 0.71, p<0.001) and pNR (AUC 0.75, p=0.010). Conclusions FDG-PET-CT after NACT identified occult metastatic disease undetected by CECT in a number of patients in this cohort, preventing futile surgery. The accuracy of FDG-PET-CT and CECT to predict ypT and ypN stage were comparable. However, CECT was more accurate for advanced tumours and FDG-PET-CT was superior for early tumours. Metabolic response on FDG-PET-CT after NACT was predictive of pathological response in both the primary tumour and LNs which may support pre-operative prognostication. These results suggest that concurrent CECT and FDG-PET-CT may be complementary for restaging and response assessment following completion of NACT prior to surgical resection.

Additional Primary Tumors Detected Incidentally on FDG PET/CT at Staging in Patients with First Diagnosis of NSCLC: Frequency, Impact on Patient Management and Survival.

We aimed to assess the frequency of additional primary malignancies detected incidentally on [18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) at staging in NSCLC patients. Moreover, their impact on patient management and survival was assessed. Consecutive NSCLC patients with available staging FDG-PET/CT between 2020 and 2021 were retrospectively enrolled. We reported whether further investigations of suspicious findings presumably not related to NSCLC were recommended and performed after FDG-PET/CT. Any additional imaging, surgery or multimodal management was considered as an impact on patient management. Patient survival was defined using overall survival OS and progression-free survival PFS. A total of 125 NSCLC patients were included, while 26 findings in 26 different patients were suspicious for an additional malignancy on FDG-PET/CT at staging. The most frequent anatomical site was the colon. A total of 54.2% of all additional suspicious lesions turned out to be malignant. Almost every malignant finding had an impact on patient management. No significant differences were found between NSCLC patients with suspicious findings versus no suspicious findings with regards to their survival. FDG-PET/CT performed for staging might be a valuable tool to identify additional primary tumors in NSCLC patients. Identification of additional primary tumors might have substantial implications for patient management. An early detection together with interdisciplinary patient management could prevent a worsening of survival compared to patients with NSCLC only.

Predictive Value of Baseline FDG-PET/CT for the Durable Response to Immune Checkpoint Inhibition in NSCLC Patients Using the Morphological and Metabolic Features of Primary Tumors.

We aimed to investigate the predictive value of baseline 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) for durable responses to immune checkpoint inhibitors (ICIs) by linking the morphological and metabolic features of primary tumors (PTs) in nonsmall cell lung cancer (NSCLC) patients. For the purpose of this single-center study, the imaging data of the patients with a first diagnosis of NSCLC and an available baseline FDG-PET/CT between 2020 and 2021 were retrospectively assessed. The baseline characteristics were collected based on clinical reports and interdisciplinary tumor board documentation. The metabolic (such as standardized uptake value SUV maximum and mean (SUVmax, SUV mean), metabolic tumor volume (MTV), total lesion glycolysis (TLG)) and morphological (such as volume, morphology, margin, and presence of lymphangiosis through imaging) features of all the PTs were retrospectively assessed using FDG-PET/CT. Overall survival (OS), progression-free survival (PFS), clinical benefit (CB) and mortality rate were used as endpoints to define the long-term response to therapy. A backward, stepwise logistic regression analysis was performed in order to define the best model for predicting lasting responses to treatment. Statistical significance was assumed at p < 0.05. A total of 125 patients (median age ± standard deviation (SD) 72.0 ± 9.5 years) were enrolled: 64 men (51.2%) and 61 women (48.8%). Adenocarcinoma was by far the most common histological subtype of NSCLC (47.2%). At the initial diagnosis, the vast majority of all the included patients showed either locally advanced disease (34.4%) or metastatic disease (36.8%). Fifty patients were treated with ICIs either as a first-line (20%) or second-line (20%) therapy, while 75 patients did not receive ICIs. The median values ± SD of PT SUVmax, mean, MTV, and TLG were respectively 10.1 ± 6.0, 6.1 ± 3.5, 13.5 ± 30.7, and 71.4 ± 247.7. The median volume of PT ± SD was 13.7 ± 30.7 cm3. The PTs were most frequently solid (86.4%) with irregular margins (76.8%). Furthermore, in one out of five cases, the morphological evidence of lymphangiosis was seen through imaging (n = 25). The median follow-up ± SD was 18.93 ± 6.98 months. The median values ± SD of OS and PFS were, respectively, 14.80 ± 8.68 months and 14.03 ± 9.02 months. Age, PT volume, SUVmax, TLG, the presence of lymphangiosis features through imaging, and clinical stage IV were very strong long-term outcome predictors of patients treated with ICIs, while no significant outcome predictors could be found for the cohort with no ICI treatment. The optimal cut-off values were determined for PT volume (26.94 cm3) and SUVmax (15.05). Finally, 58% of NSCLC patients treated with ICIs had a CB vs. 78.7% of patients in the cohort with no ICI treatment. However, almost all patients treated with ICIs and with disease progression over time died (mortality in the case of disease progression 95% vs. 62.5% in the cohort without ICIs). Conclusion: Baseline FDG-PET/CT could be used to predict a durable response to ICIs in NSCLC patients. Age, clinical stage IV, lymphangiosis features through imaging, PT volume (thus PT MTV due to a previously demonstrated linear correlation), PT SUVmax, and TLG were very strong long-term outcome predictors. Our results highlight the importance of linking clinical data, as much as morphological features, to the metabolic parameters of primary tumors in a multivariate outcome-predicting model using baseline FDG-PET/CT.

577. FDG PT-CT METABOLIC TUMOUR AND NODAL RESPONSE AS A PREDICTOR OF PATHOLOGICAL RESPONSE AND SURVIVAL IN PATIENTS WITH OESOPHAGEAL ADENOCARCINOMA

Abstract 2-deoxy-2[18F]fluoro-D-glucose positron emission tomography-computed tomography (FDG-PET-CT) is routinely used for staging of oesophageal cancer and has an emerging role in assessing response to neoadjuvant therapy. The primary aim of this study was to evaluate the ability of FDG-PET-CT to predict pathological response in the primary tumour (pTR) and lymph nodes (pNR) in patients with oesophageal adenocarcinoma undergoing neoadjuvant chemotherapy before surgery. The secondary aim was to assess the prognostic effect of metabolic and pathological response. Cohort study of 75 patients with locally advanced oesophageal or oesophago-gastric junctional adenocarcinoma who underwent FDG-PET-CT before and after neo-adjuvant chemotherapy, prior to surgical resection at a tertiary referral centre in the United Kingdom, between 2017-2020. Standardised uptake value (SUV) metrics related to the primary tumour and loco-regional lymph nodes were derived. pTR and pNR were evaluated using the Mandard classification. Receiver operator characteristic (ROC) analysis was performed and area under the curve (AUC) calculated to determine optimum SUVmax thresholds for metabolic response in the primary tumour (mTR) and lymph nodes (mNR). Survival was assessed using multivariable Cox regression. ROC analysis demonstrated an optimum tumour SUVmax decrease of 51.2% for predicting pTR. A pragmatic 50% cut-off provided better prediction of pTR (AUC 0.714, sensitivity 73.5%, specificity 69.2%, p<0.001) than PERCIST (30% reduction) and MUNICON (35% reduction) criteria. Using a 30% SUVmax threshold and excluding metabolically negative nodes, mNR demonstrated high sensitivity but low specificity (sensitivity 92.6%, specificity 57.1%, p=0.010) for predicting pNR. pTR, mTR, pNR and mNR were independent prognostic factors (pTR responder HR 0.10 95% CI 0.03-0.34; mTR responder HR 0.17 95% CI 0.06-0.48; pNR responder HR 0.17 95% CI 0.06-0.54; mNR responder HR 0.13 95% CI 0.02-0.66). Metabolic response predicted pathological response in both the primary tumour and lymph nodes in this cohort of patients with locally advanced oesophageal adenocarcinoma treated with neo-adjuvant chemotherapy. Metabolic tumour response, pathological tumour response, metabolic nodal response and pathological nodal response were all independent prognostic factors for survival. Currently utilised metabolic response criteria may not be optimal for this tumour group.

Enhanced immune reaction resulting from co-vaccination of WT1 helper peptide assessed on PET-CT.

It has become evident that positron emission tomography/computed tomography (PET-CT) using 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) (FDG PET-CT) can detect anti-tumor immune response induced by various immunotherapies. To evaluate whether FDG PET-CT could detect anti-cancer immune response caused by cancer vaccine therapy, we performed a retrospective analysis of FDG PET-CT imaging of patients who were treated with Wilms Tumor 1 (WT1) vaccine therapy in Osaka University during July 2008 and June 2018. Increased FDG uptakes were detected in WT1-vaccinated skin and their draining lymph nodes during the repeated vaccination. While the FDG uptakes seemed to decrease with time after the cessation of WT1 peptide vaccinations, persistence of FDG uptakes for years in WT1-vaccinated skin were also observed in 2 cases who showed good clinical course. Moreover, the FDG uptakes of patients treated with the combination vaccine of WT1 specific cytotoxic T cell (CTL) and helper peptides were significantly stronger than of those treated with the WT1 CTL peptide alone. Since it is evident that the combination vaccine can induce a more robust anti-tumor immunity than can CTL peptide vaccine alone, the FDG uptakes in WT1-vaccinated skin might reflect the degree of immune response. These results suggest that PET-CT might be a good tool for prediction of anti-tumor immune response induced by WT1 vaccine therapy. Larger scale prospective studies therefore seem to be warranted.

Monitoring and management of lung cancer patients following curative-intent treatment: clinical utility of 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography.

A large number of studies have demonstrated that 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) is superior to conventional modalities for the diagnosis of lung cancer and the evaluation of the extent of the disease. However, the efficacy of PET/CT in a follow-up surveillance setting following curative-intent treatments for lung cancer has not yet been established. We reviewed previous papers and evaluated the potential efficacy of PET-CT in the setting of follow-up surveillance. The following are our findings: 1) PET/CT is considered to be superior or equivalent to conventional modalities for the detection of local recurrence. However, inflammatory changes and fibrosis after treatments in local areas often result in false-positive findings; 2) the detection of asymptomatic distant metastasis is considered to be an advantage of PET/CT in a follow-up setting. However, it should be noted that detection of brain metastasis with PET/CT has some limitation, similar to its use in pretreatment staging; 3) additional radiation exposure and higher medical cost arising from the use of PET/CT should be taken into consideration, particularly in patients who might not have cancer after curative-intent treatment and are expected to have a long lifespan. The absence of any data regarding survival benefits and/or improvements in quality of life is another critical issue. In summary, PET/CT is considered to be more accurate and sensitive than conventional modalities for the detection of asymptomatic recurrence after curative-intent treatments. These advantages could modify subsequent management in patients with suspected recurrence and might contribute to the selection of appropriate treatments for recurrence. Therefore, PET/CT may be an alternative to conventional follow-up modalities. However, several important issues remain to be solved. PET/CT in a follow-up surveillance setting is generally not recommended in clinical practice at the moment.

The Importance of FDG-PET/CT in Cogan's Syndrome.

The present study gives a detailed report of a patient with atypical Cogan’s syndrome with uveitis and sensorineural hearing loss. Cogan’s syndrome is characterized by nonsyphilitic interstitial keratitis and audiovestibular dysfunction. This syndrome can be divided into two groups, typical and atypical, based on the presence of interstitial keratitis. It may sometimes be associated with systemic vasculitis. Fluoro-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) scanning was used to investigate the presence of vasculitis. With FDG-PET/CT scanning, there is no pathological involvement in the walls of the arteries; thus the patient is protected from aggressive and long term immunosuppressive treatment’s side effects. Hence, we can conclude that FDG-PET/CT may play an important role in excluding the presence of vasculitis.

Use of positron emission tomography-computed tomography in the management of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) cells typically have low 2-deoxy-2-[18F]fluoro-d-glucose (FDG) avidity, and patients with CLL have an increased risk of developing FDG-avid aggressive lymphomas, second malignancies and infections. We hypothesized that FDG positron emission tomography-computed tomography (PET-CT) of the trunk is a sensitive method of detecting these complications in patients with CLL. Of the of 2299 patients with CLL seen in the Division of Hematology at Mayo Clinic Rochester between 1 January 2006 and 31 December 2011, 272 (11.8%) had 526 PET-CT scans and 472 (89.7%) of these were reported as abnormal. Among the 293 (55.7%) PET-CT scans used for routine evaluation of CLL, the PET component was of clinical value in only one instance. In contrast, in 83 (30.5%) patients, PET-CT scans used to evaluate new clinical complications localized high FDG-avidity lesions for biopsies. This resulted in clinically relevant new diagnoses in 32 patients, including those with more aggressive lymphoma (n = 16), non-hematological malignancies (n = 8) and opportunistic infections (n = 3). Twenty-seven patients had high FDG-avidity CLL, which was associated with prominent lymph node proliferation centers, an increased frequency of poor prognostic factors (17p13 deletion, unmutated immunoglobulin heavy chain variable gene [IGHV], expression of ZAP-70 and CD38) and a shorter overall survival. We conclude that FDG PET scans should not be used for routine surveillance of patients with CLL. However PET-CT scans are sensitive, but not specific, for detection of aggressive lymphomas, other cancers and systemic infections in patients with CLL.

Clinical Utility of PET/CT Scanning in Patients with Chronic Lymphocytic Leukemia

AbstractAbstract ▪3903▪This icon denotes a clinically relevant abstractThe clinical utility of 2-deoxy-2-[18F] fluoro-D-glucose (FDG) positron emission tomography-computed tomography (PET-CT) scans in the management of patients with chronic lymphocytic leukemia (CLL) has not been clearly defined. CLL cells typically have low FDG avidity and the addition of the PET component has not been shown to improve the utility of CT scans in the management of patients with CLL. However, patients with CLL are at increased risk of developing FDG avid complications including more aggressive lymphomas, other second malignancies, and infections for which FDG PET-CT scans are a useful imaging modality. We hypothesized that FDG PET-CT scans are sensitive tests for evaluation of these complications in patients with CLL. Patients and Methods:This observational study was performed with IRB approval. We studied all 4030 CLL patients seen at least once in the Division of Hematology at Mayo Clinic Rochester between January 1, 2006 and December 31, 2011 using data prospectively collected into the Mayo Clinic CLL database. We reviewed the clinical and radiological records of the 272 (7%) patients who underwent 526 FDG PET-CT scans of the trunk during this time period to determine the indication for PET-CT scan, results of imaging, and the effects of the use of PET/CT scan on management. Results:Four hundred and seventy two (90%) of the 526 PET-CT scans were reported as abnormal. Of these, 78 (17%) scans were useful in directing a tissue biopsy of high FDG avidity lesions. Of the 37 (8%) positive PET-CT scans that facilitated the diagnosis of new complications of CLL, 21 (4%) scans led to a diagnosis of diffuse large B cell lymphoma and 9 (2%) scans led to a diagnosis of a solid malignancy. The FDG component of 22 PET-CT scans done because of clinical suspicion of complications of CLL were negative, and thus useful in management of these patients. PET-CT scans showed progressive CLL in 138 (29%) studies but in these patients, the PET component of the scan did not provide additional information about the status of the patients' CLL compared to the CT component alone. Conclusions:FDG PET-CT scans are not of proven value in staging CLL or determining response to treatment. However, our data suggest that they could be of considerable value in evaluation for complications, especially more aggressive lymphomas, other cancers, and infections that complicate the course of CLL. Disclosures:Off Label Use: Phase I study using PGG beta glucan in CLL. Zent:Biothera: Research Funding; Genzyme: Research Funding; Genentech: Research Funding; Novartis: Research Funding; GlaxoSmithKline: Research Funding.

F-18 FDG-PET/CT in aseptic abscesses with recurrent febrile abdominal pain

Objective. Mendelian and complex autoinflammatory disorders frequently manifest as recurrent abdominal pain and fever. Diagnosis may be difficult and scant data are available about the interest of 2-deoxy-2-[18F]fluoro-d-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in such conditions, particularly aseptic abscesses (AA). Material and methods. We analyzed five cases of AA in which FDG-PET/CT was performed at diagnosis (n = 2) and after a suspected relapse (n = 5). Follow-up FDG-PET/CT was performed in two patients 9 days and 6 weeks after the initiation of oral corticosteroids. Results. FDG-PET/CT showed intense uptake foci in the abdominal lymph nodes (n = 4), liver (n = 2) and spleen (n = 4) before treatment. A marked metabolic response was observed while patients were being treated. In a relapsing patient with abdominal pain but no raised CRP, although CT scan was unchanged, abnormal uptake of FDG was observed. By contrast, some lesions previously observed on CT scan displayed no fixation on new FDG-PET/CT and were suggestive of sequelae in three patients. Conclusion. Although nonspecific, FDG-PET/CT may be an interesting tool for the diagnosis and management of recurrent and febrile abdominal pain in AA. At the time of relapse, it can differentiate between a sequela of previous flares and a new localization. It can be used for whole-body screening to look for other asymptomatic disease localizations.

Quantitative Assessment of Diffusion-Weighted MR Imaging in Patients with Primary Rectal Cancer: Correlation with FDG-PET/CT

PurposeThe aim of the study was to assess correlations between parameters on diffusion-weighted imaging and 2-deoxy-2-[18F]fluoro-d-glucose–positron emission tomography/computed tomography (FDG-PET/CT) in rectal cancer.ProceduresThirty-three consecutive patients with pathologically confirmed rectal adenocarcinoma were included in this study. Apparent diffusion coefficient (ADC) maps were generated to calculate ADCmean (average ADC), ADCmin (lowest ADC), tumor volume, and total diffusivity index (TDI). PET/CT exams were performed within 1 week of magnetic resonance imaging. Standardized uptake values (SUVs) were normalized to the injected FDG dose and body weight. SUVmax (maximum SUV), SUVmean (average SUV), tumor volume, and total lesion glycolysis (TLG) were calculated using a 50% threshold.ResultsSignificant negative correlations were found between ADCmin and SUVmax (r = −0.450, p = 0.009), and between ADCmean and SUVmean (r = −0.402, p = 0.020). A significant positive correlation was found between TDI and TLG (r = 0.634, p < 0.001).ConclusionThe significant negative correlations between ADC and SUV suggest an association between tumor cellularity and metabolic activity in primary rectal adenocarcinoma.

Sequential FDG-PET/CT after Neoadjuvant Chemotherapy is a Predictor of Histopathologic Response in Patients with Head and Neck Squamous Cell Carcinoma

To evaluate whether 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) more accurately predicts the histopathologic response to neoadjuvant chemotherapy (NAC) than magnetic resonance imaging (MRI) in patients with head and neck squamous cell carcinoma (HNSCC). Sixteen patients with HNSCC underwent FDG-PET/CT and MRI scans before and after one cycle of NAC, followed by surgical resection. The 26 surgically resected specimens of the 16 patients were analyzed. Decreases in maximum standardized uptake value (SUV(max)) or in tumor maximum size (diameter(max)) were calculated, and their accuracies for the prediction of histopathologic response were evaluated. In histopathologic responders (n = 7), percent decreases in SUV(max) were significantly higher (P < 0.001) than in non-responders (n = 19). Applying a cut-off point of 55.5%, the histopathologic response could be predicted with a sensitivity and specificity of 86% and 95%, respectively. FDG-PET/CT can predict histopathologic NAC responses with higher accuracy than MRI in HNSCC patients.

Integrated FDG-PET-CT: its role in the assessment of bone and soft tissue tumors

The purpose of this study was to evaluate prospectively, whether integrated 2-deoxy-2-[(18)F]fluoro-D: -glucose positron emission tomography-computed tomography (FDG-PET-CT) is more accurate for determination musculoskeletal tumors compared with separate interpretation of CT and FDG-PET, because most of the current clinical data come from patients studied with PET. Eighty patients with newly diagnosed musculoskeletal tumors underwent FDG-PET-CT. CT, FDG-PET, and FDG-PET-CT were interpreted separately to determine the performance of each imaging modality. Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity and accuracy for CT alone was 81, 84, 83%, for PET 71, 82, 76, and for PET-CT 80, 83 and 86%. Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 61, 100, 70%, for PET 69, 100, 79, and for PET-CT 69, 100 and 79%. Combined FDG-PET-CT reliably differentiates soft tissue and bone tumors from benign lesions. The value of the information provided by FDG-PET-CT for planning surgical procedures must be evaluated in further studies.

Prognostic Value of 18F-FDG PET/CT in Patients with Malignant Pleural Mesothelioma

To evaluate prognostic value of integrated 2-deoxy-2-[F-18]fluoro-D: -glucose-positron emission tomography/computed tomography (FDG-PET/CT) and correlate histopathological subtype with maximum standardized uptake value (SUV(max)) and survival in patients with malignant mesothelioma (MM). Retrospective review of FDG-PET/CT scans, with derivation of SUV(max) of FDG-avid lesions, was performed in patients with biopsy-proven MM. Clinical follow-up and Kaplan-Meier survival analysis was performed. Forty-six patients (37 M:9 F; mean age 61 years) with MM had a FDG-PET/CT scan in a 30-month period. Follow-up was available on 44/46 (96%) patients. Metastatic disease was detected in 9/46 (20%) patients on FDG-PET/CT, where 8/9 were previously undetected. Better survival was found in patients without metastases (p value < 0.05). Mean SUV(max) of primary pleural lesions in patients with metastatic disease was significantly higher than in patients without metastatic disease (p value < 0.05). Progression-free survival was significantly better in the epithelioid histology group compared to the biphasic group (p value 0.015). Detection of extrathoracic metastases on FDG-PET/CT and nonepithelioid histopathology are poor prognostic indicators in patients with MM.

Radioisotopic Localization of 90Yttrium–Ibritumomab Tiuxetan in Patients with CD20+ Non-Hodgkin’s Lymphoma

(90)Yttrium-ibritumomab-tiuxetan (Zevalin) is an effective treatment for relapsed or refractory low-grade, follicular, or transformed B-cell NHL. The purpose of this study is to assess whether tissue and cellular localization of (90)Y-ibritumomab-tiuxetan determined by autoradiography and radioactivity localized to tumor tissue might enhance our understanding of the mechanism of action of radioimmunotherapy. Eight eligible patients had CD20+ NHL, a bulky peripheral lymph node, and were scheduled for (90)Y-ibritumomab-tiuxetan treatment. 2-Deoxy-2-[F-18]fluoro-D: -glucose-positron emission tomography/computed tomography (FDG-PET/CT) was performed prior to treatment and at 12 weeks after therapy for assessment of response. Bone marrow, lymph node, and blood samples were collected 114 +/- 3 h after 14.8 MBq/kg (90)Y-ibritumomab-tiuxetan and processed for histology, scintillation counting, and microscopic autoradiography. Pericellular membrane localization of (90)Y-ibritumomab-tiuxetan to lymphoma cells was observed by autoradiography in the involved areas of lymph node with absence of significant localization in histologically normal sections of bone marrow. Pericellular radioactivity and the highest quantitative radioactivity were observed in lymph node samples of responding patients. (90)Y-ibritumomab-tiuxetan localizes to the surface membrane of CD20+ lymphoma cells in affected lymph nodes. The patients with the highest quantitative concentration of radioactivity to the lymph node as determined by scintillation counting were observed to have a clinical and FDG-PET/CT response.

Performance of Integrated FDG-PET/CT for Differentiating Benign and Malignant Lung Lesions -Results from a Large Prospective Clinical Trial

The purpose of the study was to evaluate prospectively whether integrated 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) is more accurate for determination of malignancy in newly diagnosed pulmonary lesions compared to separate interpretation of CT and FDG-PET. Two hundred and seventy-six patients with newly diagnosed lung lesions underwent FDG-PET/CT. Helical CT, FDG-PET, and FDG-PET/CT were interpreted separately to determine the performance of each imaging modality. Histopathology served as reference in all patients, and in further 60 patients, a benign lesion was verified at follow-up (mean follow-up of 1,040 days). Histology revealed malignant lung tumors in 216 of 276 patients. With PET and PET/CT, a significantly lower number of lesions were classified as equivocal compared to CT alone (p < 0.001). Assuming that equivocal lesions are benign, performance of diagnostic tests was as follows: sensitivity, specificity, and accuracy for CT was 94, 75, and 90%, for PET 97, 83, and 94% (p = 0.021), and for PET/CT 96, 87, and 94% (p = 0.010). Assuming that equivocal lesions are malignant, sensitivity, specificity, and accuracy for CT was 99, 37, and 86%, for PET 99, 77, and 94% (p < 0.001), and for PET/CT 98, 68, and 92% (p = 0.002). PET and PET/CT showed the highest concordance (K = 0.912; confidence interval 0.866-0.958). In lesions less than or equal to 3 cm, there was a significant difference in the performance of PET alone and multidetector row CT as well as PET/CT and multidetector row CT (p = 0.007), irrespective if equivocal findings were judged as malignant or benign. For differentiation of benign from malignant lung lesions, integrated FDG-PET/CT imaging was significantly more accurate than CT but not FDG-PET. The addition of metabolic imaging (FDG-PET) to morphological imaging (CT) leads to an increase in specificity and significantly reduced equivocal findings and is therefore recommended to further specify newly diagnosed lung lesions.

Chronic bronchitis mimicking metastases from thyroid medullary carcinoma demonstrated by indium-111 pentetreotide scintigraphy

We present a case of medullary thyroid carcinoma (MTC) with pulmonary symptoms, elevated calcitonin and CEA levels. Both [111In]pentetreotide (Octreoscan) scintigraphy and 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) scan revealed mild increased uptake of radionuclides in the upper lobe of the right lung compatible with metastases. Histopathological analysis showed it to be chronic bronchitis. The patient was followed without any treatment. Three months later, no pathological uptake on [111In]pentetreotide (Octreoscan) was observed. False positive [111In]pentetreotide uptake in the lungs was likely related to acute exacervation of the chronic bronchitis.

123I MIBG Mapping with Intraoperative Gamma Probe for Recurrent Neuroblastoma

Intraoperative gamma probe guidance has become widely utilized for sentinel lymph node dissection in patients with breast cancer and melanoma, using (99m)Tc sulfur colloid. However, new indications are possible and need to continue to be investigated. We report the use during a wedge liver biopsy of a new hand-held gamma probe designed for (123)I intraoperative guidance. The patient studied is a 5-year-old boy with history of stage 4 high-risk neuroblastoma. Anatomic imaging (CT, MRI), (99m)Tc bone scintigraphy and 2-deoxy-2-[F-18]fluoro-d-glucose-positron emission tomography/computed tomography (FDG-PET/CT) were negative, but the (123)I MIBG scintigraphy suggested recurrent liver disease. A decision was made to biopsy these lesions to obtain histopathological confirmation. Intraoperative gamma probe mapping of the liver identified areas with signal above the background, but these were prove to be hemosiderin deposits on histo-pathology examination.

Recurrence of head and neck cancer after surgery or irradiation: prospective comparison of 2-deoxy-2-[F-18]fluoro-D-glucose PET and MR imaging diagnoses.

To evaluate the diagnostic accuracy of positron emission tomography (PET) with administration of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) relative to that of magnetic resonance (MR) imaging and/or computed tomography (CT) in recurrent head and neck cancers. Twelve adult patients (mean age, 63 years) with previously treated head and neck cancers and clinical suspicion of recurrence underwent FDG PET and MR imaging and/or CT. All images were blindly and independently interpreted without histopathologic findings (obtained within 1 week of imaging). The level of confidence in image interpretation was graded by using a five-point rating system (0 = definitely no recurrence to 4 = definite recurrence). Recurrence was confirmed in eight patients. With a rating of 4 as a positive finding, FDG PET yielded a sensitivity and specificity of 88% (seven of eight) and 100% (four of four), respectively; MR imaging and/or CT, 25% (two of eight) and 75% (three of four), respectively. Receiver-operating characteristic analysis showed significantly better diagnostic accuracy with FDG PET than with MR imaging and/or CT (area under curve = 0.96 vs 0.55, P < .03). These data indicate that PET metabolic imaging, as compared with anatomic methods, has improved diagnostic accuracy for recurrent head and neck cancer.