fluoro-2-deoxy-D-glucose Positron Emission Tomography Research Articles

2-[18f]-Fluoro–2-deoxy-d-glucose positron emission tomography in the evaluation of breast lesions and axillary involvement: a comparison with mammography and histopathological diagnosis

The objective of this prospective study was to evaluate the potential role of 2-[18f]-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in the differentiation of malignant and benign breast masses and the evaluation of axillary lymph node involvement. The secondary objective of this study was to assess the value of FDG PET in the initial staging of patients with breast cancer. Materials and methods: We evaluated 82 lesions in 79 consecutive patients (mean age of 54.4 ± 13.0; age range: 25-82 years) with FDG PET. While ultrasounds were performed in all cases, of the 79 patients, 72 had mammography and 58 had whole-body bone scintigraphy. All patients had a histopathological diagnosis made by 2 experienced pathologists. Results: The sensitivity and positive predictive value of FDG PET in the differentiation of breast masses was found as 78% and 98%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET in the detection of metastatic axillary invasion was 50%, 76%, 53%, and 64%, respectively. FDG PET changed the stage of 41 patients (52%) by either downstaging [33 (41%) patients] or upstaging [8 (11%) patients], respectively. Conclusion: Our results suggest that FDG PET has limited value in differentiating between malignant and benign breast lesions and in the detection of metastatic axillary lymph nodes. However, FDG PET appears to have great impact in the initial staging of patients with breast cancer and could be very helpful in the management of selected cases.

Role of FDG‐PET as a biological marker for predicting the hypoxic status of tongue cancer

To determine whether 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) could serve as a useful technique predicting tumor hypoxia and prognosis in tongue cancer, we assessed the relationship between FDG uptake and the levels of hypoxia-related markers. Tumor uptake of FDG in 33 patients with T2 tongue cancer was assessed by measuring maximum standardized uptake values (SUVmax). Expression of hypoxia-inducible factor (HIF)-1α, carbonic anhydrase (CA)-9, glucose transporter (GLUT)-1, and erythropoietin receptor (EPOR), was determined by immunohistochemical staining. Correlation between SUVmax and the expression of hypoxia-related markers was assessed and multivariate analysis was performed to determine what parameters affected clinical outcomes. We observed strong correlations between SUVmax and expression of HIF-1α (p < .05), CA-9 (p < .01), and GLUT-1 (p < .01). SUVmax, HIF-1α expression, and tumor grade were significant independent predictors of disease-free survival (DFS). SUVmax may be a good noninvasive biomarker for prediction of hypoxic status and prognosis of patients with T2 tongue cancer.

Evidence-based Guideline Recommendations on the use of Positron Emission Tomography Imaging in Oesophageal Cancer

AimsTo provide evidence-based practice guideline recommendations on the use of fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) for diagnosis, staging, assessing treatment response, liver metastasis and restaging or recurrence of oesophageal cancer. Materials and methodsA systematic review by Facey et al. (Health Technology Assessment 2007;11(44):iii–iv, xi–267) was used as the evidence base for recommendation development. As the review was limited to August 2005, the evidence base was updated to May 2010 using the same search strategies for MEDLINE and EMBASE used in the original review. The authors of the current systematic review drafted recommendations, which were reviewed, adapted and accepted by consensus by the Ontario provincial Gastrointestinal Disease Site Group and a special meeting of clinical experts. ResultsThe results from the Facey et al. review for oesophageal cancer included four other systematic reviews and six primary studies. The 2005 to 2010 updated search included two additional systematic reviews and 29 primary studies. Recommendations were developed based on this evidence and accepted by consensus. ConclusionsPET is recommended to improve the accuracy of M staging for the staging work-up of patients with oesophageal cancer who are potential candidates for curative therapy. Due to insufficient evidence, no recommendation was made for or against the use of PET for the assessment of treatment response and the evaluation of suspected recurrence.

Pitfalls in PET/CT imaging

PET with 2-[fluorine 18] fluoro-2-deoxy-d-glucose (FDG), has been a clinical tool for the evaluation of various cancers providing valuable metabolic information clinically helpful in the diagnosis, initial staging, therapy monitoring and restaging. However, FDG is not specific for neoplastic processes. Unless anatomic correlation is available to delineate normal structures, pathologic sites of FDG accumulation can easily be confused with normal physiological uptake, leading to false-positive or false-negative findings. Coregistration of PET scans (functional and morphologic information) with computed tomographic (CT) scans (anatomic information) using a combined PET-CT scanner improves the overall sensitivity and specificity of information provided by PET or CT alone. In this paper, we discuss the probable causes of false negative images and pitfalls due to technical reasons, inflammatory processes or benign lesions as well as the utility of PET-CT in differentiating malignant from inflammatory and benign processes, since in some cases such differentiation cannot be made, with certainty, using FDG PET alone.

The use of dual-phase 18F-FDG PET in characterizing thyroid incidentalomas

To examine the usefulness of dual-phase 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) for the evaluation of thyroid incidentalomas. In this retrospective study, cases with focal thyroid lesions seen incidentally at FDG PET in which the histopathological diagnosis was available and in which dual-phase FDG PET imaging was performed at 1 and 2 h after FDG injection were reviewed. In the included cases, the 1 and 2 h maximal standard uptake value (1-hour maximal SUV and 2-hour maximal SUV, respectively) and retention index (RI) were calculated, and the differences between benign and malignant thyroid incidentalomas were analysed. Receiver operating characteristic (ROC) analysis was performed to evaluate the ability of 1-hour maximal SUV, 2-hour maximal SUV, and RI to discriminate benign from malignant lesions. A total of 39 patients (25 females, 14 males) with 45 lesions (17 malignant, 28 benign) were included. In malignant thyroid incidentalomas, the average 1-hour maximal SUV, 2-hour maximal SUV, and RI were 5.20, 5.72, and 7.67%, respectively, and in benign thyroid incidentalomas the values were 4.67, 4.97, and 7.38%, respectively. There were no significant differences in 1-hour maximal SUV, 2-hour maximal SUV, and RI between benign and malignant lesions. The area under the ROC curve did not differ from 0.5. Dual-phase FDG PET is not useful for differentiating benign from malignant thyroid incidentalomas.

The Frequency and Spectrum of Thymus 2-[Fluorine-18] Fluoro-2-deoxy-D-glucose Uptake Patterns in Hyperthyroidism Patients

Thymic hyperplasia is associated with hyperthyroidism. Increased thymus 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) uptake in hyperthyroidism patients has been reported. The aim of this study was to analyze the FDG positron emission tomography (PET) thymus uptake spectrum in patients with active hyperthyroidism with correlation with serum hormones. The prospective study included FDG PET scans from 65 hyperthyroidism patients and 30 subjects with euthyroid status as control group. The intensity of FDG uptake in thyroid and thymus regions was graded subjectively on a five-point scale and semi-quantitatively by measuring standard uptake value (SUV). Correlation coefficient between thymus SUV and serum thyroxine, triiodothyronine, thyrotropin, thyroid peroxidase antibodies (TPO Ab), thyrotropin receptor autoantibody (TR Ab), and thymulin were analyzed. Among 65 hyperthyroidism patients, 30 (46.2%) and 39 (60%) patients showed thyroid and thymus FDG uptake, respectively. The frequency of thymus uptake FDG was high in patients younger than age 40 (28/31, 90.3%). The patterns of the thymic FDG uptake include inverted V or triangular, separated triangular, united nontriangular, unilateral right or left extension, and focal midline. Focal midline FDG uptake was the most common pattern (15/39, 38.5%). None of the control group showed thymus FDG uptake. The correlation coefficient between the FDG uptake SUV levels in thymus and serum hormones, thyrotropin, TPO Ab, TR Ab, and thymulin levels were all low (P > .05). In FDG PET scan, thymus activity was common in hyperthyroidism patients; this should not be misdiagnosed as a malignancy in patients exhibiting weight loss.

Two cases of benign esophageal schwannoma with positive FDG-PET findings

We report two cases of rare benign esophageal schwannoma showing high uptake of radiotracer on [18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET). Case 1 was a 78-year-old woman with a tumor (50 × 30 × 30 mm) located on the right side of the upper thoracic esophagus. Case 2 was a 70-year-old woman with a tumor (40 × 35 × 27 mm) located in the left anterior wall of the thoracic-to-cervical esophagus. Both tumors were enucleated and histologically diagnosed as benign esophageal schwannoma with nuclear palisading and lymphoid cuffing (Antoni A type). Immunohistochemical staining showed positivity for S-100 protein. There have been five reported cases of esophageal schwannoma with FDG-PET findings, including the present two cases. All five tumors were FDG-PET positive and presented histologically as benign esophageal schwannoma. There was no association between histological malignancy and FDG uptake. We therefore propose that the malignant potential of esophageal schwannomas cannot be evaluated using FDG-PET.

Consistency of FDG-PET Accuracy and Cost-Effectiveness in Initial Staging of Patients With Hodgkin Lymphoma Across Jurisdictions

Two hundred ten patients with newly diagnosed Hodgkin's lymphoma (HL) were consecutively enrolled in this prospective trial to evaluate the cost-effectiveness of fluorine-18 ((18)F)-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) scan in initial staging of patients with HL. All 210 patients were staged with conventional clinical staging (CCS) methods, including computed tomography (CT), bone marrow biopsy (BMB), and laboratory tests. Patients were also submitted to metabolic staging (MS) with whole-body FDG-PET scan before the beginning of treatment. A standard of reference for staging was determined with all staging procedures, histologic examination, and follow-up examinations. The accuracy of the CCS was compared with the MS. Local unit costs of procedures and tests were evaluated. Incremental cost-effectiveness ratio (ICER) was calculated for both strategies. In the 210 patients with HL, the sensitivity for initial staging of FDG-PET was higher than that of CT and BMB in initial staging (97.9% vs. 87.3%; P < .001 and 94.2% vs. 71.4%, P < 0.003, respectively). The incorporation of FDG-PET in the staging procedure upstaged disease in 50 (24%) patients and downstaged disease in 17 (8%) patients. Changes in treatment would be seen in 32 (15%) patients. Cumulative cost for staging procedures was $3751/patient for CCS compared to $5081 for CCS + PET and $4588 for PET/CT. The ICER of PET/CT strategy was $16,215 per patient with modified treatment. PET/CT costs at the beginning and end of treatment would increase total costs of HL staging and first-line treatment by only 2%. FDG-PET is more accurate than CT and BMB in HL staging. Given observed probabilities, FDG-PET is highly cost-effective in the public health care program in Brazil.

Pilot study to evaluate the effect of erlotinib (E) administered before surgery in operable patients with squamous cell carcinoma of the head and neck (SCCHN).

5568 Background: Strategies for early detection of cellular response to EGFR inhibitors are critical to personalizing therapy for SCCHN. The glycolytic enzymes responsible for uptake of the positron emission tomography (PET) tracer [18F] 2- fluoro-2-deoxy-d-glucose (FDG) are regulated by intermediates of the EGFR pathway such as AKT, mTOR and MAPK. It was hypothesized that the inhibition of these EGFR pathway markers could be read by the 18[F]-FDG uptake by tumor. It is also possible that the EGFR pathway is aberrantly activated in some cancers and that glycolysis and downstream effects are not always linked. Previous in vitro and in vivo studies showed that 18[F]-FDG uptake changes very early in SCCHN tumor models responsive to EGFR inhibition. We developed a pilot clinical protocol to investigate this further in patients with SCCHN. Methods: Patients with operable SCCHN with a window of at least 15 days between the time of initial biopsy and established surgery will receive E 150 mg/day or 300 mg/day if the patient is actively smoking. Smokers metabolize E rapidly with an MTD that is twice that of non-smokers. Patients must have additional biopsy tissue for laboratory research studies. 18[F]-FDG PET scan and neck CT with contrast are performed before treatment, 4-6 days through treatment and at the end of E administration. Results: 11 patients have been treated to date with an average of 18.6 days of treatment. Of the 10 evaluable patients, 7 showed partial response (PR) and 3 patients showed stable disease (SD). 8 patients received E 300 mg. No grade 3 or 4 toxicities. Early (4-6 days)18[F]-FDG PET scans showed a decrease in SUV max to 93.25% +/- 18% in patients with SD and to 51% +/- 22% in patients with PR (defined as at least 20% reduction in maximum diameter). This pilot trial will continue to enroll patients to address the primary laboratory research correlative aim. Pre-and post-treatment tumor tissue is available in all patients. Conclusions: Short course treatment with E in a dose adjusted per smoking status is very active in previously untreated patients with SCCHN. Early changes in the 18[F]-FDG PET scan uptake can be used as a marker predictive of response to EGFR inhibition.

A mass originating from chronic pyothorax in the pleural cavity

A 71-year-old male with a past history of tuberculous pleuritis was referred to our hospital in 2008 because of right chest pain. Chest computed tomography (CT) demonstrated a huge mass originated from chronic pyothorax in the right pleural cavity, invading the chest wall. 2-[F]fluoro-2-deoxy-D-glucose Positron Emission Tomography (FDG-PET) imaging showed strong uptake only in the tumor of the right chest wall (Image 1A). Immunohistochemical staining and Southern blot hybridization of biopsied specimens revealed that the diagnosis was CD20 negative pyothorax-associated diffuse large B cell lymphoma. In situ hybridization for Epstein-Barr virus (EBV) disclosed EBV-encoded small RNA expression in the lymphoma cells. Clinical stage was IE, and international prognostic index was low intermediate. First, three courses of pirarubicin-cyclophosphamide, vincristine, prednisolone (COP) were administered. Then confirming that FDG-PET became negative (Image 1B), involved-field radiotherapy of 50 Gy was added. No sign of relapse has been found for more than 2 years. Pyothorax-associated lymphoma (PAL) is defined as nonHodgkin’s lymphoma of exclusively B-cell phenotype developing in the pleural cavity of patients with chronic pyothorax [1,2]. Most of PAL cases express CD20; however, there are a small proportion of cases which do not express B cell antigens such as CD20 and CD79a [3,4]. It is suggested that PAL is strongly associated with EBV [5,6]. A mass in the pleural cavity with a history of tuberculosis should cause one to consider PAL in the differential diagnosis.

F-18-FDG-PET Confined Radiotherapy of Locally Advanced NSCLC With Concomitant Chemotherapy: Results of the PET-PLAN Pilot Trial

The integration of fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) in the process of radiotherapy (RT) planning of locally advanced non-small-cell lung cancer (NSCLC) may improve diagnostic accuracy and minimize interobserver variability compared with target volume definition solely based on computed tomography. Furthermore, irradiating only FDG-PET-positive findings and omitting elective nodal regions may allow dose escalation by treating smaller volumes. The aim of this prospective pilot trial was to evaluate the therapeutic safety of FDG-PET-based RT treatment planning with an autocontour-derived delineation of the primary tumor. Eligible patients had Stages II-III inoperable NSCLC, and simultaneous, platinum-based radiochemotherapy was indicated. FDG-PET and computed tomography acquisitions in RT treatment planning position were coregistered. The clinical target volume (CTV) included the FDG-PET-defined primary tumor, which was autodelineated with a source-to-background algorithm, plus FDG-PET-positive lymph node stations. Limited by dose restrictions for normal tissues, prescribed total doses were in the range of 66.6 to 73.8 Gy. The primary endpoint was the rate of out-of-field isolated nodal recurrences (INR). As per intent to treat, 32 patients received radiochemotherapy. In 15 of these patients, dose escalation above 66.6 Gy was achieved. No Grade 4 toxicities occurred. After a median follow-up time of 27.2 months, the estimated median survival time was 19.3 months. During the observation period, one INR was observed in 23 evaluable patients. FDG-PET-confined target volume definition in radiochemotherapy of NSCLC, based on a contrast-oriented source-to-background algorithm, was associated with a low risk of INR. It might provide improved tumor control because of dose escalation.

A Comparative Study of F-18 FDG PET and 201Tl Scintigraphy for Detection of Primary Malignant Bone and Soft-Tissue Tumors

The purpose of this study was to compare 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) and Tl-201 chloride (Tl) scintigraphy for detection of primary malignant bone and soft-tissue tumors. A total of 40 patients with suspicion of malignant bone and soft-tissue tumors were examined. FDG PET imaging was performed at 1-hour post-FDG injection. Tl planar and single photon emission computed tomography images were acquired 10 minutes (early) and 2 hours (delayed) after injection of Tl. We evaluated FDG and Tl uptake visually and semiquantitatively using standardized uptake value and tumor to contralateral normal tissue ratio on planar images, respectively. Of the 33 patients with malignant tumors, all but 2 liposarcomas showed positive accumulation on FDG PET. However, all 7 benign lesions were also positive on FDG PET. Both early and delayed Tl images were positive for 27 of the 33 malignant tumors. Of the 6 false-negative cases on Tl images, 5 were liposarcomas. Both early and delayed Tl images were negative for 5 of the 7 benign lesions. The sensitivity of FDG PET for detection of primary malignant bone and soft-tissue tumors was 94% and the specificity, 0%. The corresponding values for Tl scintigraphy were 82% and 71%. The mean FDG standardized uptake value in malignant tumors was higher than that in benign lesions, but this difference was not statistically significant. Statistically significant differences were observed between malignant and benign lesions for both early and delayed tumor to contralateral normal tissue ratios. FDG PET was found to be more sensitive than Tl scintigraphy for primary malignant bone and soft-tissue tumors, although it was less specific.

Clinical usefulness of dual-time FDG PET–CT in assessment of esophageal squamous cell carcinoma

We conducted this study to investigate the value of the dual-time 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography-computed tomography (PET-CT) in assessment of the primary tumor, loco-regional lymph node and distant metastasis in patients with esophageal squamous cell carcinoma. Twenty-six patients with histologically proved esophageal squamous cell carcinoma underwent dual-time FDG PET-CT before radical surgery. The standardized uptake values (SUV(max)) were obtained including early SUV(max) and delayed SUV(max), respectively. The retention index (RI) was also calculated. The results were evaluated retrospectively according to the final pathologic findings. Four diagnostic criteria including (1) early SUV(max)≧ 2.5 alone, (2) RI ≧ 10% alone, (3) a combination of early SUV(max)≧ 2.5 and RI ≧ 10%, and (4) a combination of early SUV(max)≧ 2.5 or RI ≧ 10% were used for differentiating malignancy from a benign lesion, respectively. The sensitivity of FDG PET-CT in detecting the primary tumor with combination of early SUV(max)≧ 2.5 or RI ≧ 10% was 96.2%. It was statistically significantly higher than the results using the other three criteria (p<0.0001). For loco-regional lymph node detection, there was no significant difference among the 4 criteria. For distal metastases, the significantly higher specificity (100%) was found when using combination of early SUV(max)≧ 2.5 and RI ≧ 10% or using early SUV(max)≧ 2.5 alone than using the other two criteria (p=0.0058). With regard to accuracy, no significant correlations were observed among primary tumor, loco-regional lymph nodes and distant metastasis (p>0.05). The preliminary result of this study demonstrated that dual-time point FDG PET-CT had limited value in detection of primary tumor and loco-regional lymph nodes metastasis. For the distant metastasis, the sensitivity and specificity would be improved if RI ≧ 10% is used as a supplemental criterion. Efforts should be made to improve the ability of the dual-time FDG PET-CT technique to assess primary tumor and loco-regional lymph nodes metastasis.

Personalized Treatment of Lymphoma: Promise and Reality

Lymphoma comprises two groups of diseases: Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL). Within both subsets are numerous variations with distinct biologic, molecular, and cytogenetic characteristics. The World Health Organization (WHO) classification of NHL, for example, now identifies several dozen broad entities and nearly 60 unique clinicopathologic subtypes. In addition to pathologic heterogeneity, there is clinical diversity within lymphomas, with some patients achieving cure, others having prolonged disease stabilization, and still others experiencing a rapidly fulminant decline and death. It is increasingly appreciated that both clinical and biological features strongly influence outcome. Practical implementation of a personalized approach to treatment is urgently needed, but efforts thus far have focused primarily on prognostication, with much less emphasis on determining therapeutic options. Nevertheless, better prognostic tools will facilitate the design of "risk-stratified" trials that will ultimately benefit patients. Thus far, the development of personalized treatment in lymphomas clusters into several broad approaches: refinement of clinical prognostic models for better risk stratification, use of high-throughput technology to identify biologic subtypes within pathologically similar diseases, "response-adapted" changes in therapy via imaging with [(18)F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET), and anti-idiotype vaccines. An important unmet need is the implementation of these tools into treatment choices for individual patients, and this is the focus of intense ongoing research.

FDG-PET for the diagnosis of fever of unknown origin: a Japanese multi-center study

To evaluate the clinical value of 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) for the diagnosis of fever of unknown origin (FUO), we performed a Japanese multi-center retrospective survey. A total of 81 consecutive patients with FUO who underwent FDG-PET at 6 institutions between July 2006 and December 2007 were retrospectively evaluated. FDG uptake was visually evaluated using a 4-grade scale. The efficacy of FDG-PET for the evaluation of FUO, the provision of additional diagnostic information, the clinical impact on therapeutic decisions (4-grade scale), and the diagnostic performance compared with the final diagnosis were evaluated. The diagnostic results were analyzed according to 4 groups of final diagnoses: infection, arthritis/vasculitis/autoimmune/collagen disease (A/V), tumor/granuloma (T/G), and other/unknown (O/U). Sensitivity was highest in T/G, followed by infection, A/V and O/U [100%(7/7), 89%(24/27), 65%(11/17), 0%(0/1) respectively]. Clinical impact and mean FDG score showed the same tendency. Additional information was highest in infection followed by T/G, A/V, and O/U [76%(22/29), 75%(6/8), 43%(9/21), 23%(5/22), respectively]. The O/U group showed a high specificity (84%, 16/19) and accurately excluded active focal inflammatory diseases and malignancy. The use of steroids for the treatment of fever seemed to mask the lesions and modified the results, especially in the A/V group (4 false negatives in 8 steroid users out of 21 A/V patients). The prevalence of each disease in each hospital significantly affected the effectiveness of FDG-PET for the diagnosis of FUO. The mean FDG uptake score and additional information (70%, 31/44 vs. 30%, 11/37, respectively) in national hospital (NH) was significantly higher than in university hospitals (UH). A Grade 3 clinical impact, in which the FDG PET results changed the clinical decision, was seen in 50% (22/44) of the patients in the NH group and 13.5% (5/37) of the patients in the UH group. The sensitivity (91%, 30/33; 63%, 12/19) and specificity (60%, 6/10; 86%, 12/14) of the results in the NH and UH groups differed. The total sensitivity was 81% (42/52), specificity was 75% (18/24). The NH group included a large number of cases with infectious diseases (50%, 23/44), while the UH group included a large number of A/V cases (38%, 14/37) and O/U cases (41%, 15/37). FDG-PET for the diagnosis of FUO provided additional diagnostic information and had a high clinical impact, especially among patients with infectious diseases. It was also helpful in cases with unknown or other miscellaneous diseases by allowing the exclusion of focally active diseases. The prevalence of diseases in hospitals significantly affected the effectiveness of FDG-PET for the diagnosis of FUO. FDG-PET is a useful examination providing various degrees of clinical impact for the management of FUO, depending on the characteristics of the patient and the hospital.

A visual [18F]FDG-PET rating scale for the differential diagnosis of frontotemporal lobar degeneration

This study presents a visual rating scale for the assessment of cerebral [(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) scans to characterize typical findings in dementias associated with frontotemporal lobar degeneration (FTLD) and to differentiate individual patients with FTLD compared to Alzheimer's disease (AD) and mild cognitive impairment (MCI). A total of 43 cerebral PET scans from patients with FTLD (n = 16, mean age 58.4 years), AD (n = 16, 59.9 years) and MCI (n = 11, 57.9 years) were analysed. Every PET data set was visually rated for seven brain regions on each hemisphere (frontal lobe, temporal lobe, parietal lobe, occipital lobe, basal ganglia, thalamus and cerebellum). The extent of the impairment in metabolism was classified as absent, mild, medium or strong. Using this four-stage visual rating scale, characteristic profiles of metabolic impairment in FTLD, AD, MCI and the FTLD-subgroup FTD (n = 9) could be demonstrated. Patients with FTLD showed a significantly lower metabolism in the left frontal lobe and in the left basal ganglia when compared to AD and to MCI. Complementary analyses using statistical parametric mapping (SPM2) supported the findings of the visual analysis. In detecting FTLD with visual rating, sensitivity/specificity was 81/94% compared to AD and 81/64% compared to MCI. Patients with FTD were correctly attributed to a diagnosis of FTLD with a sensitivity of 89%. This visual rating scale may facilitate the differential diagnosis of FTLD in clinical routine.

Diagnostic Usefulness of 3’-Deoxy-3’-[18F]Fluorothymidine Positron Emission Tomography in Recurrent Brain Tumor

We evaluated the diagnostic usefulness of 3'-deoxy-3'-[F]fluorothymidine (FLT) compared with 2-[F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in recurrent brain tumors. Twenty patients with suspected recurrence after surgical removal of primary tumors were studied. The uptake was assessed visually and quantified by standardized uptake value (SUV) and SUV ratio of tumor to white matter, tumor to gray matter, and tumor to normal tissue. Final diagnoses were made by histopathology or clinical and radiological follow-up. Of 20 lesions, 15 were recurrences. 3'-Deoxy-3'-[F]fluorothymidine PET showed high diagnostic sensitivity (15/15 [100%]) and moderate specificity (3/5 [60.0%]). 2-[F]fluoro-2-deoxy-D-glucose PET showed moderate diagnostic sensitivity (11/15 [73.3%]) and specificity (4/5 [80%]). All of 4 recurrent tumors without FDG uptake showed FLT uptake. Tumor-to-normal tissue ratios (3.99 ± 1.72) of recurrent tumors on FLT PET were significantly higher than tumor-to-white matter ratios (1.96 ± 0.93) and tumor-to-gray matter ratios (1.32 ± 0.33) on FDG PET (P < 0.001), although SUVs (0.62 ± 0.32) of recurrent tumors on FLT PET were lower than those (2.44 ± 1.02) on FDG PET (P < 0.001). 3'-Deoxy-3'-[F]fluorothymidine PET has a high sensitivity but a lower specificity, which has a limited role in the diagnosis of recurrent brain tumors as a complimentary tool of magnetic resonance imaging.

The role of dual time point FDG PET imaging in the evaluation of solitary pulmonary nodules with an initial standard uptake value less than 2.5

To evaluate the accuracy of dual time point 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET) imaging in the evaluation of the mildly metabolic solitary pulmonary nodule (SPN) and to assess whether accuracy could be improved by delaying second image acquisition to 180 minutes. Fifty-four patients were included in the study. Thirty-six had an SUV(max) <2.5 at 60 min. For these patients, two methods of interpreting the subsequent delayed FDG PET imaging at 180 min were investigated. The first method analysed the SUV(max) of SPNs on delayed imaging, in which an SUV(max) of 2.5 or more was regarded as a criterion for malignancy. The second method was retention index (RI) analysis, in which an increase of 10% or more in SUV(max) between the initial and delayed images, was regarded as an indication of malignancy. For the group as a whole (n=54), the sensitivity, specificity and accuracy of using an SUV(max) of 2.5 or more as an indication of malignancy at the time of initial image acquisition (60 min) was 58, 89, and 74%, respectively. For SPNs that had an initial SUV(max) <2.5 (n=36), the sensitivity, specificity, and accuracy of using an SUV(max) of 2.5 or more as a criterion for malignancy on the delayed image acquisition (180 min), was 36, 96, and 78% respectively. However, if an RI of >10% was used as a criterion for malignancy between the initial and delayed images, the sensitivity, specificity, and accuracy was 73, 80, and 78%, respectively. These results are similar to a recent paper, where image acquisition occurred at 60 and 120 min post-tracer injection. Dual time point FDG PET imaging with RI analysis, is a useful technique in evaluating SPN with an initial SUV(max) <2.5. Prolonging second image acquisition from 120 to 180 min does not appear to improve the accuracy of this technique. However, given that maximal FDG uptake by lung carcinomas is thought to be in the region of 5h, it may be that improving the accuracy of dual time point FDG PET imaging requires a more significant delay in second image acquisition in this specific subgroup.

Early stage non-small-cell lung cancer: challenges in staging and adjuvant treatment: evidence-based staging

Staging of non-small-cell lung cancer is a multidisciplinary process involving imaging, endoscopic and surgical techniques. Accuracy is vital in order to avoid false-positive interpretations leading to a false stage III or IV diagnosis in early stage patients, or false-negative findings leading to a false early stage diagnosis in patients with mediastinal lymph node disease. CT scan offers great anatomical detail of tumour spread, but radiological imaging lacks information on the biological nature of the lesions. The latter is brought in by 2-[fluorine-18] fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) scan as a metabolic imaging tool, which, however, has clearly lower spatial resolution. Therefore, contemporary staging relies on the combination of both, preferably in a fusion PET-CT scan. Absence of suspected lymph node metastasis on both CT and PET has a high negative predictive value, and these patients may in general proceed to surgery. In most others, tissue confirmation of the locoregional lymph node status is needed. The historical standard of mediastinoscopy is nowadays complemented by endoscopic techniques by the bronchial or esophageal approach. Each of these techniques remains important in modern staging algorithms. A practical scheme for rational staging in clinical practice is discussed.

GLUCOSE METABOLISM IN PROGRESSIVE NONFLUENT APHASIA WITH AND WITHOUT PARKINSONISM

Progressive nonfluent aphasia (PNFA) is one of the language variants of frontotemporal dementia.1 Previously, PNFA, corticobasal degeneration (CBD), and progressive supranuclear palsy (PSP) were regarded as separate disease entities because of their distinctive clinical features and different anatomic involvement: left perisylvian area in PNFA,2 basal ganglia and dorsal midbrain in PSP, and perirolandic area in CBD.3 However, recent studies show that the 3 disorders share tauopathy and clinical features such as language disturbance and parkinsonism in common.4 Furthermore, one disorder even evolves into others along the course of disease progression.5 One of the typical examples of this evolution is that PNFA can develop into CBD or PSP.6 Therefore, we hypothesized that the topography of glucose hypometabolism in patients with PNFA with parkinsonism (PNFA+P) would differ from those without parkinsonism (PNFA-P), even before evolving into PSP or CBD. That is, PNFA+P would have more glucose hypometabolism in the basal ganglia, midbrain, or perirolandic areas that are known to be affected in PSP or CBD. ### Methods. #### Subjects. We retrospectively found a total of 21 patients with PNFA who underwent clinical evaluations, including neuropsychological tests and [18F]fluoro-2-deoxy-d-glucose PET (FDG-PET) within a 3-month interval at a university-affiliated hospital. All patients fulfilled the diagnostic criteria for PNFA proposed …