18F-FDG positron emission tomography CT (FDG PET-CT) in the management of pancreatic cancer: initial experience in 12 patients.

INTRODUCTION: Staging and restaging of pancreatic malignancy can be demanding. Often, there are liver lesions seen on diagnostic CT suspicious for secondary deposits. Positron emission tomography (PET)-CT may have a great potential in confirming or ruling out actual malignancy in those areas. METHODS: We prospectively studied 12 pancreatic adenocarcinoma patients, who had undergone PET-CT imaging as part of their staging or restaging process. Imaging was performed after intravenous administration of 10 mCi F-18 FDG. Results were compared with CT, histopathological findings and/or clinical follow up. RESULTS: PET-CT correctly identified 11 lesions and ruled the absence of disease in 4 out of 4 patients (PPV 92%, NPV of 100%, and accuracy 94%), compared to CT which had (PPV 79%, NPV 50% and accuracy 75%). CT identified 4 metastatic liver lesions in 12 patients of which 3 were actually benign processes. CONCLUSION: FDG-PET detects pancreatic malignancy and metastatic disease with higher accuracy than conventional CT. The ability of PET-CT to rule out or correctly identify metastases greatly enhances the physician's decision-making process to choose the right therapeutic intervention.

Functional imaging: II. Prediction of epilepsy surgery outcome.

OBJECTIVE: To gain information on the value of magnetic source imaging (MSI), 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), and ictal single photon emission computed tomography (SPECT) to predict seizure-free outcome following epilepsy surgery in patients who require intracranial electroencephalography (ICEEG). METHODS: This work was part of a prospective observation study of epilepsy surgery candidates not sufficiently localized with scalp EEG and MRI. Of 160 patients enrolled 62 completed ICEEG and subsequent surgical resection. Sixty-one percent resulted in an Engel I seizure-free outcome at a minimum of one-year follow-up (mean = 3.4 years). Sensitivity, specificity, and predictive values were computed for each modality. Multivariate logistical regression was used to identify prediction of surgical outcome by imaging test. RESULTS: MSI sensitivity for a conclusively localized study was 55% with a positive predictive value of 78%. Eliminating non-diagnostic MSI cases (no spikes captured during recording) yielded a corrected negative predictive value of 64%. With available comparison subgroups FDG-PET and ictal SPECT values were similar to MSI. The OR (adjusted for epilepsy and MRI classification) for MSI prediction of seizure-free outcome was 4.4 (p =0.01). In cases with both PET and MSI, the adjusted OR for PET was 7.1 (p <0.01) and for MSI was 6.4 (p = 0.01). In the cases with all three tests (n = 27), ictal SPECT had the highest OR of 9.1 (p = 0.05). INTERPRETATION: MSI, FDG-PET, and ictal SPECT each have clinical value in predicting seizure-free surgical outcome in epilepsy surgery candidates who typically require ICEEG.

Functional imaging: I. Relative predictive value of intracranial electroencephalography.

OBJECTIVE: To gain information on the predictive and prognostic value of magnetic source imaging (MSI), 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography ((18)FDG-PET), and ictal single-photon emission computed tomography (SPECT) as compared with intracranial electroencephalography (ICEEG) localization in epilepsy surgery. METHODS: This work was part of a cohort study of epilepsy surgery candidates not sufficiently localized with noninvasive studies. Of 160 patients enrolled over 4 years, 77 completed ICEEG seizure monitoring. Sensitivity, specificity, and predictive values relative to ICEEG were computed for each modality. RESULTS: Seizures were not captured in five patients. Of the 72 diagnostic ICEEG studies, seizure localization results were 74% localized, 10% multifocal, and 17% nonlocalized. Sixty-one percent were localized to neocortical regions. Depending on patient subgroup pairs, sensitivity ranged from 58 to 64% (MSI), 22 to 40% (PET), and 39 to 48% (SPECT); specificity ranges were 79 to 88% (MSI), 53 to 63% (PET), and 44 to 50% (SPECT). Gains in diagnostic yield were seen only with the combination of MSI and PET or MSI and ictal SPECT. Localization concordance with ICEEG was greatest with MSI, but a significant difference was demonstrated only between MSI and PET. Moderate redundancy was seen between PET and ictal SPECT (kappa = 0.452; p = 0.011). INTERPRETATION: Conclusively positive MSI has a high predictive value for seizures localized with ICEEG. Diagnostic gain may be achieved with addition of either PET or ictal SPECT to MSI. Diagnostic values for imaging tests are lower than "true values" because of the limitations of ICEEG as a gold standard.

Radiation safety protocol for high dose 131I therapy of thyroid carcinoma in patients on hemodialysis for chronic renal failure.

Iodine ablation therapy for thyroid cancer on patients receiving dialysis poses unique radiation safety challenges. Exposure to gamma and beta negative particles by the hemodialysis (HD) staff is a concern that has not been well studied. A 53-y-old male patient on HD for chronic renal failure was scheduled for 131I high dose therapy as treatment for thyroid papillary carcinoma. The patient was on HD every other day, prior to ablation. A high dose of 131I (3,607.5 MBq) was required. The patient was admitted for 131I therapy, and continued HD. Thyroid cancer ablation therapy was administered according to our institutional protocol. New radiation safety measures were developed and implemented in order to give the patient an optimal treatment dose, reduce radiation to the patient (critical organs and whole body), and to protect the HD personnel. This included placing two lead shields between the patient and the HD nurse, and HD monitoring by two alternating nurses to reduce their radiation exposure. Film badges were used to measure radiation exposure to the nursing staff. Dosimetry calculations were obtained to determine radiation absorbed doses by the optic lens, skin, and whole body. Quality control verification for this shielding arrangement proved to be effective in protecting the HD staff against gamma and beta negative radiation from recent 131I high dose therapy. Implementation of this model proved to be an effective and adequate radiation safety protocol for limiting radiation exposure to the HD staff. The patient was given 3607.5 MBq for optimal treatment after HD. Hemodialysis was repeated after approximately 48 and 96 h to remove excess 131I and reduce radiation to the patient.

Maximum standard uptake value of mediastinal lymph nodes on integrated FDG-PET-CT predicts pathology in patients with non-small cell lung cancer.

BACKGROUND: Positron emission tomography (PET) scans often help direct biopsies of mediastinal lymph nodes in patients with non-small cell lung cancer (NSCLC), but the maximum standard uptake value (maxSUV) of individual nodes has not been evaluated. METHODS: This is a prospective study of consecutive patients with NSCLC, all of whom underwent integrated fluorodeoxyglucose-positron emission-computed tomography (FDG-PET-CT) and had biopsy or resection of their mediastinal lymph nodes. RESULTS: There were 397 patients. One-hundred and forty-three patients had N2 disease and 1,252 N2 nodes were pathologically examined. The median maxSUV of the nodes that had metastatic disease were the following: for the 2R node, 10.4 (range, 0-18.6); for 4R, 8.6 (range, 0-18.3); for 5, 8.9 (range, 0-26.3); for 6, 7.6 (range, 0-19.6); for 7, 7.7 (range, 0-14); for 8 and 9, 5.4 (range, 0-8.9). The median maxSUV for all of the N2 nodes that were benign was 0 (range, 0-18.8) (p < 0.05 for all stations except for nodes 8 and 9). When a maxSUV of 5.3 is used the accuracy of integrated FDG-PET-CT for each N2 nodal station is maximized and is at least 92% for each. CONCLUSIONS: The maxSUV of individual mediastinal lymph nodes is a predictor of malignancy. There is overlap between false and true positives. Definitive biopsies are required to prove cancer irrespective of the maxSUV value. However, when a maxSUV of 5.3 is used instead of the traditional value of 2.5, the accuracy for FDG-PET-CT for each N2 nodal station increases to at least 92%.

Restaging patients with N2 (stage IIIa) non-small cell lung cancer after neoadjuvant chemoradiotherapy: a prospective study.

BACKGROUND: The accuracy of restaging in patients with stage IIIa non-small cell lung cancer after neoadjuvant chemoradiotherapy is unknown. METHODS: A prospective trial of patients with biopsy-proven N2 disease who underwent initial clinical staging with mediastinoscopy, integrated positron emission tomography/computed tomography (PET/CT), and CT. Patients then were clinically restaged by the same imaging techniques 4 to 12 weeks after their induction chemoradiation therapy and then underwent definitive pathologic staging. RESULTS: Ninety-three patients had their lymph nodes pathologically restaged. Repeat PET/CT after neoadjuvant therapy missed residual N2 disease in 13/65 (20%) patients and falsely suggested it in 7 of 28 (25%). It was more accurate than repeat CT for restaging at all pathologic stages (stage 0, 92% vs 39%, P = .03; and stage I 89% vs 36%, P = .04). When the maximum standardized uptake value of the primary tumor is decreased by 75% or more, it is highly likely (likelihood ratio, +LR, 6.1) the patient is a complete responder; when it decreased by 55% or more, it is highly likely (+LR, 9.1) the patient is a partial responder. When the maximum standardized uptake value of the N2 node initially involved with metastatic cancer is decreased by more than 50%, it is highly likely (+LR, 7.9) the node is now benign. CONCLUSION: Repeat integrated PET/CT is superior to repeat CT for the restaging of patients with stage IIIa non-small cell lung cancer. The percent decrease in the maximum standardized uptake value of the primary and of the involved lymph node is predictive of pathology; however, nodal biopsies are required since a persistently high maximum standardized uptake value does not equate to residual cancer.

Improving the inaccuracies of clinical staging of patients with NSCLC: a prospective trial.

BACKGROUND: Clinical stage affects the care of patients with nonsmall cell lung cancer. METHODS: This is a prospective trial on patients with suspected resectable nonsmall cell lung cancer. All patients underwent integrated positron emission tomographic scanning and computed tomographic scanning, and all suspicious metastatic sites were investigated. A, T, N, and M status was assigned. If N2, N3 and M1 were negative, patients underwent thoracotomy and complete thoracic lymphadenectomy. RESULTS: There were 383 patients. The accuracy of clinical staging using positron emission tomographic scanning and computed tomographic scanning was 68% and 66% for stage I, 84% and 82% for stage II, 74% and 69% for stage III, and 93% and 92% for stage IV, respectively. N2 disease was discovered in 115 patients (30%) and was most common in the subcarinal lymph node (30%). Unsuspected N2 disease occurred in 28 patients (14%) and was most common in the posterior mediastinal lymph nodes (subcarinal, 38%; posterior aortopulmonary, 15%). It was found in 9% of patients who were clinically staged I (58% in the posterior mediastinal lymph nodes) and in 26% of patients clinically staged II (86% in posterior mediastinal lymph nodes). CONCLUSIONS: Despite integrated positron emission tomographic scanning and computed tomographic scanning, clinical staging remains relatively inaccurate for patients with nonsmall cell lung cancer. Recent studies suggest adjuvant therapy for stage Ib and II nonsmall cell lung cancer; thus the impact on preoperative care is to find unsuspected N2 disease. Unsuspected N2 disease is most common in posterior mediastinal lymph nodes inaccessible by mediastinoscopy. Thus one should consider endoscopic ultrasound fine-needle aspiration, especially for patients clinically staged as I and II, even if the nodes are negative on positron emission tomographic scanning and computed tomographic scanning.

Endoscopic ultrasound-guided fine needle aspiration of mediastinal lymph node in patients with suspected lung cancer after positron emission tomography and computed tomography scans.

BACKGROUND: The treatment of patients with non-small cell lung cancer (NSCLC) depends on the stage. Positron emission and computed tomography (CT) scans can identify suspicious lymph nodes that require biopsy. We prospectively evaluated the yield and accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in sampling mediastinal lymph nodes and compared its accuracy to that of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and CT in staging NSCLC. METHODS: A consecutive series of patients with suspicious nodes on PET or CT scan in the posterior mediastinal lymph node stations (#5, 7, 8, or 9) were prospectively evaluated by EUS-FNA. The reference standard included thoracotomy with complete lymphadenectomy in patients with lung cancer or if EUS-FNA was benign, repeat clinical imaging, or long-term follow-up. RESULTS: There were 104 patients (63 men) with 125 lesions (117 lymph nodes, 8 left adrenal glands) who underwent EUS-FNA. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EUS-FNA were 92.5%, 100%, 100%, 94%, and 97%, respectively. EUS-FNA was more accurate and had a higher positive predictive value than the PET or CT (p < 0.001) scan in confirming cancer in the posterior mediastinal lymph nodes. EUS-FNA documented metastatic cancer to the left adrenal in all 4 patients with advanced disease. No deaths resulted from EUS-FNA. One patient experienced self-limited stridor. CONCLUSIONS: EUS-FNA is a safe, accurate, and minimally invasive technique that improves the staging of patients with NSCLC. It is more accurate and has a higher predictive value than either the PET scan or CT scan for posterior mediastinal lymph nodes.

The role of FDG-PET scan in staging patients with nonsmall cell carcinoma.

BACKGROUND: To assess the role of flourodeoxyglucose-positron-emission tomography (FDG-PET) scan in staging patients with nonsmall cell lung cancer (NSCLC). METHODS: We prospectively studied 400 patients with NSCLC. Each patient underwent a computed tomography (CT) scan of the chest and upper abdomen, other conventional staging studies and had a FDG-PET scan within 1 month before surgery. All suspicious N2 lymph nodes by either chest CT or by FDG-PET scan were biopsied. Patients that were N2 and M1 negative underwent pulmonary resection and complete thoracic lymphadenectomy. RESULTS: The FDG-PET had a higher sensitivity (71% vs 43%, p < 0.001), positive predictive value (44% vs 31%, p < 0.001), negative predictive value (91% vs 84%, p = 0.006), and accuracy (76% vs 68%, p = 0.037) than CT scan for N2 lymph nodes. Similarly, FDG-PET had a higher sensitivity (67% vs 41%, p < 0.001), but lower specificity (78% vs 88%, p = 0.009) than CT scan for N1 lymph nodes. FDG-PET led to unnecessary mediastinoscopy in 38 patients. FDG-PET was most commonly falsely negative in the subcarinal (#7) station and the aortopulmonary window lymph node (#5, #6) stations. It accurately upstaged 28 patients (7%) with unsuspected metastasis and it accurately downstaged 23 patients (6%). CONCLUSIONS: The FDG-PET scan allows for improved patient selection. It more accurately stages the mediastinum, however there are many false positives lymph nodes and it may be more likely to miss N2 disease in the #5, #6, and #7 stations. A positive FDG-PET scan means a tissue biopsy is indicated in that location.

Positron emission tomography scanning with 2-fluoro-2-deoxy-d-glucose as a predictor of response of neoadjuvant treatment for non-small cell carcinoma.

OBJECTIVES: Surgical resection after preoperative chemotherapy in patients with non-small cell lung cancer might only be best for patients who are responders. We compared positron emission tomographic scanning with 2-fluoro-2-deoxy-d-glucose (FDP-PET scanning) with computed tomographic scanning to evaluate their ability to predict this response for the primary tumor, N1 and N2 lymph nodes. METHODS: All patients with non-small cell lung cancer who had an initial FDP-PET scan staging with tissue biopsy, neoadjuvant chemotherapy, repeat FDP-PET scanning, and repeat biopsies were prospectively studied. RESULTS: There were 34 patients (24 men; median age, 64 years). Eleven patients had N2 disease, and 7 had N1 disease. Twenty-seven patients received chemotherapy, and 7 patients received chemotherapy and radiation. All but 9 patients underwent resection. Statistical analysis showed FDP-PET scanning to be more specific (P <.0001), to have a higher positive predictive value (P =.0018), and to have a higher negative predictive value (P <.0001) than computed tomographic scanning for predicting residual tumor at the primary site. FDP-PET scanning was more sensitive (P <.0001) and more accurate (P <.0001), had a higher positive predictive value (P <.0001), and had a higher negative predictive value (P =.0002) than computed tomographic scanning for paratracheal nodes (number 2 and 4 lymph nodes). FDP-PET scanning had a higher positive predictive value (P <.0001) than computed tomographic scanning for the other N2 (numbers 5, 6, 7, 8, and 9) lymph nodes. CONCLUSIONS: Repeat FDP-PET scanning is more specific and has a higher positive predictive value and negative predictive value than computed tomographic scanning for detecting residual tumor in the lung in patients with non-small cell lung cancer who have received preoperative chemotherapy. It is more sensitive and accurate for paratracheal N2 nodes as well. However, there is no significant difference in its detection of N1 lymph nodes.

Recurrent lymphoma detected on F-18 FDG coincidence imaging with negative findings on Ga-67 citrate scintigraphy.

Ga-67 citrate scintigraphy and computer tomography have been used in tumor staging, to determine disease extent, and for the pre- and post-therapeutic management of Hodgkin's and non-Hodgkin's lymphoma. Today, localization of hypermetabolic tissue using F-18 FDG is beginning to play a role in the staging and restaging of lymphoma. The authors report a case of recurrent Hodgkin's lymphoma in a 31-year-old man detected by F-18 FDG. Findings of the Ga-67 citrate scintigram were negative. Palpable right axillary adenopathy was found on routine physical examination follow-up. Comparison with previous negative findings obtained with Ga-67 citrate was unchanged. However, computed tomography revealed new right axilla lymphadenopathy, prompting further investigation with F-18 FDG SPECT, which showed hypermetabolic activity corresponding to the region of the right axilla involvement. Pathologic examination showed changes indicative of interfollicular recurrence of Hodgkin's lymphoma.