18F-2-deoxy-2-fluoro-glucose Positron Emission Tomography (FDG-PET) has been recently proposed as a promising cancer-screening test. However, the validity of FDG-PET in cancer screening has not been evaluated. We investigated the sensitivity of FDG-PET compared with upper gastric endoscopy in gastric cancer screening for asymptomatic individuals. A total of 2861 consecutive subjects (1600 men and 1261 women) who were asymptomatic and who underwent both FDG-PET and upper gastrointestinal endoscopy between 1 February 2004 and 31 January 2005 were included in this study. Both endoscopists and a radiologist were unaware of the results of the other diagnostic tests. The FDG-PET images were examined using criteria determined by the pattern of FDG accumulation. Sensitivity and specificity of FDG-PET were calculated compared with endoscopic diagnosis as the gold standard. Among 2861 subjects enrolled in the study, there were 20 subjects with gastric cancer, of whom 18 were T1 in depth of cancer invasion. Positive FDG-PET results were obtained only in 2 of the 20 cancer subjects. The calculated sensitivity and specificity for overall gastric cancers were 10.0% (95% confidence interval (CI): 1.2–31.7%) and 99.2% (95% CI: 98.8–99.5%), respectively. 18F-2-deoxy-2-fluoro-glucose Positron Emission Tomography was poorly sensitive for detection of gastric cancer in the early stages.
gastric cancer; screening; endoscopy; FDG-PET; sensitivity
Positron emission tomography with 2-deoxy-2-[18F]fluoro-d-glucose (FDG-PET) is available for evaluation of patients with melanoma. This study evaluates the potential of FDG-PET to improve on conventional imaging (CI) in patients with stage IV melanoma undergoing metastasectomy.
This was a prospective study comparing radiological evaluation of patients who underwent metastasectomy for palliation or cure. Patients underwent preoperative evaluation by physical examination, CI by computed tomography and/or magnetic resonance imaging, and FDG-PET. Independent observers performed three separate analyses of CI alone, FDG-PET alone, or FDG-PET read with knowledge of CI (FDG-PET + CI). Abnormalities were reported as benign or malignant and assessed by pathologic analysis or by clinical outcome determined by disease progression detected on serial evaluations.
Ninety-four lesions were noted in 18 patients who underwent preoperative assessment, metastasectomy, and long-term follow up (median, 24 months). Lesion-by-lesion analysis for CI demonstrated a sensitivity of 76%, a specificity of 87%, a positive predictive value (PPV) of 86%, and a negative predictive value (NPV) of 76%. FDG-PET demonstrated a sensitivity of 79%, a specificity of 87%, a PPV of 86%, and an NPV of 80%. For FDG-PET + CI, the sensitivity was 88%, specificity was 91%, and PPV and NPV were 91% and 88%, respectively.
Combined use of FDG-PET and CI may be an accurate strategy to identify sites of disease in patients with stage IV melanoma being considered for metastasectomy. Interpreted independently, FDG-PET and CI seemed to be equivalent modalities. FDG-PET + CI had both the highest sensitivity on lesion-by-lesion analysis and the best accuracy on patient-by-patient analysis.
Melanoma; Cancer; FDG-PET; Imaging; Metastasectomy; Surgery
The role of positron emission tomography with the glucose analogue [18F] fluoro‐2‐deoxy‐D‐glucose (FDG‐PET) in the initial staging of disease in patients with primary colorectal cancer (CRC) has not been adequately assessed.
To evaluate the additional value of FDG‐PET as a staging modality, complementary to routine multidetector row computed tomography (MDCT) in patients with CRC.
Forty four patients with CRC underwent preoperative MDCT and FDG‐PET. The accuracy of intraoperative macroscopic staging was also investigated compared with histopathological diagnosis. All FDG‐PET images were evaluated with respect to detectability of the primary tumour, lymph node involvement, and distant metastases. Both MDCT and FDG‐PET diagnoses and treatment plan were compared with surgical and histopathological results.
Thirty seven patients underwent surgery. Tumour detection rate was 95% (42/44) for MDCT, 100% (44/44) for FDG‐PET, and 100% (37/37) for intraoperative macroscopic diagnosis. Pathological diagnosis of T factor was T1 in five, T2 in four, T3 in 24, and T4 in four cases. Concordance rate with pathological findings of T factor was 57% (21/37) for MDCT and 62% (23/37) for macroscopic diagnosis. Lymph node involvement was pathologically positive in 19 cases. Regarding N factor, overall accuracy was 62% (23/37) for MDCT, 59% (22/37) for FDG‐PET, and 70% (26/37) for macroscopic diagnosis. For all 44 patients, FDG‐PET findings resulted in treatment changes in only one (2%) patient.
FDG‐PET is not superior to routine MDCT in the initial staging of primary CRC.
positron emission tomography; colorectal surgery; spiral computed tomography; colorectal neoplasms; neoplasm staging
The case reported here was that of an old woman characterized by pancytopenia, chromosome clonal abnormality, fluctuation of the percent of blast cells at 20%, and negative evidence of malignancy in whole-body 2-[F18] fluoro-2-deoxy-d-glucose positron emission tomography (F18-FDG PET). After about 10 months, the blast cells accounted for about 25%, the morphology of which was similar to that of previous ones, and F18-FDG PET demonstrated diffusing increased uptake in the right upper leg and lymph nodes and patchy high uptake of bone marrow. 2-[F18]-fluoro-2-deoxyglucose can reflect extramedullary infiltration and bone marrow cellularity of the whole body, compared with invasive, regional biopsies and aspirations. The value of 2-[F18]-fluoro-2-deoxyglucose or 3’-deoxy-3’-[F18]-fluorothymidine positron emission tomography as an indicator in predicting the transformation of myelodysplastic syndrome to acute myeloid leukemia needs to be explored in the future.
Acute myeloid leukemia; extramedullary infiltration; F18-FDG PET; myelodysplastic syndrome
AIMS—To compare whole body positron
emission tomography (PET) using
fluorine-18-fluoro-2-deoxy-D-glucose (FDG) with computed
tomography (CT) in detecting active infective foci in children with
chronic granulomatous disease.
METHODS—We performed 22 whole body
FDG PET studies in seven children with X linked (n = 6) or autosomal
recessive (n = 1) CGD. All had clinical signs of infection and/or
were evaluated prior to bone marrow transplantation (BMT). Nineteen PET
studies were also correlated with chest and/or abdominal CT. All PET
scans were interpreted blinded to the CT findings. Diagnoses were
confirmed histologically and bacteriologically.
RESULTS—We detected 116 lesions in
22 FGD PETs and 126 lesions on 19 CTs. Only two of the latter could be
classified reliably as active lesions by virtue of contrast enhancement
suggesting abscess formation. PET excluded 59 lesions suspicious for
active infection on CT and revealed 49 infective lesions not seen on
CT. All seven active infective lesions were identified by PET, allowing
targeted biopsy and identification of the infective agent followed by
specific antimicrobial treatment, surgery, or subsequent BMT.
infective organisms is more precise if active lesions are biopsied. CT
does not discriminate between active and inactive lesions. Whole body
FDG PET can be used to screen for active infective lesions in CGD patients.
To compare the interobserver agreement and degree of confidence in anatomical localisation of lesions using 2-[fluorine-18]fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) and 18F-FDG PET alone in patients with head and neck tumours. A prospective study of 24 patients (16 male, eight female, median age 59 years) with head and neck tumours was undertaken. 18F-FDG PET/CT was performed for staging purposes. 2D images were acquired over the head and neck area using a GE Discovery LS™ PET/CT scanner. 18F-FDG PET images were interpreted by three independent observers. The observers were asked to localise abnormal 18F-FDG activity to an anatomical territory and score the degree of confidence in localisation on a scale from 1 to 3 (1=exact region unknown; 2=probable; 3=definite). For all 18F-FDG-avid lesions, standardised uptake values (SUVs) were also calculated. After 3 weeks, the same exercise was carried out using 18F-FDG PET/CT images, where CT and fused volume data were made available to observers. The degree of interobserver agreement was measured in both instances. A total of six primary lesions with abnormal 18F-FDG uptake (SUV range 7.2–22) were identified on 18F-FDG PET alone and on 18F-FDG PET/CT. In all, 15 nonprimary tumour sites were identified with 18F-FDG PET only (SUV range 4.5–11.7), while 17 were identified on 18F-FDG PET/CT. Using 18F-FDG PET only, correct localisation was documented in three of six primary lesions, while 18F-FDG PET/CT correctly identified all primary sites. In nonprimary tumour sites, 18F-FDG PET/CT improved the degree of confidence in anatomical localisation by 51%. Interobserver agreement in assigning primary and nonprimary lesions to anatomical territories was moderate using 18F-FDG PET alone (kappa coefficients of 0.45 and 0.54, respectively), but almost perfect with 18F-FDG PET/CT (kappa coefficients of 0.90 and 0.93, respectively). We conclude that 18F-FDG PET/CT significantly increases interobserver agreement and confidence in disease localisation of 18F-FDG-avid lesions in patients with head and neck cancers.
18F-FDG PET/CT; imaging; head and neck cancers; squamous cell carcinoma
It has been suggested that glucose metabolism within the brain's default network is directly associated with—and may even cause—the amyloid pathology of Alzheimer's disease (AD). Here we performed 2-[18F]fluoro-2-deoxy-D-glucose (FDG) and [11C]-labeled Pittsburgh Compound B (PIB) positron emission tomography (PET) on cognitively normal elderly subjects and on AD patients and conducted quantitative regional analysis of FDG- and PIB-PET images using an automated region of interest technique. We confirmed that resting glucose metabolism within the posterior components of the brain's default network is high in normal elderly subjects and low in AD patients, which is partially in agreement with the regional pattern of PIB uptake within the default network of AD patients. However, in several regions outside the default network, glucose metabolism was high in normal elderly subjects but was not depressed in AD patients, who exhibited significantly increased PIB uptakes in these regions. In contrast, the level of resting glucose metabolism in the default network and in regions outside the default network in normal elderly subjects was significantly correlated with the level of regional PIB uptake in AD patients. These results are discussed with experimental evidence suggesting that beta amyloid production and amyloid precursor protein regulation are dependent on neuronal activity.
The association between antemortem [11C]-Pittsburgh Compound B (PiB) retention and β-amyloid (Aβ) load, Lewy body (LB) and neurofibrillary tangle (NFT) densities were investigated in a pathologically confirmed case of dementia with LB (DLB). 76-year-old man presenting with a clinical diagnosis of DLB had undergone PiB–positron emission tomography (PET), 18F FDG-PET and MRI 18 months before death. The pathologic diagnosis was DLB neocortical-type with low-likelihood of Alzheimer's disease by NIA-Reagan criteria. Sections from regions of interest (ROI) on post-mortem examination were studied. A significant correlation was found between cortical Aβ density and PiB retention in the 17 corresponding ROIs (r=0.899; p<0.0001). Bielschowsky silver stain revealed mostly sparse neocortical neuritic plaques; whereas diffuse plaques were frequent. There was no correlation between LB density and PiB retention (r=0.13; p=0.66); nor between NFT density and PiB retention (r=−0.36; p=0.17). The ROI-based analysis of imaging and histopathological data confirms that PiB uptake on PET is a specific marker for Aβ density, but cannot differentiate neuritic from diffuse amyloid plaques in this case with DLB.
Dementia with Lewy bodies; amyloid imaging; PET; pathology; amyloid
The 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.
Thirty-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.
Significant 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).
The significant negative correlations between ADC and SUV suggest an association between tumor cellularity and metabolic activity in primary rectal adenocarcinoma.
ADC; DWI; SUV; PET/CT; Primary rectal adenocarcinoma; TDI; TLG
Flourine-18 fluoro-2-deoxy-glucose (18F-FDG) positron emission tomography combined with computed tomography (PET/CT) is a useful test for the management of malignant conditions. Inflammatory and infectious processes, however, can cause increased uptake on PET scanning, often causing diagnostic dilemmas. This knowledge is important to the rheumatologist not only because of the inflammatory conditions we treat but also because certain rheumatic diseases impose an increased risk of malignancy either due to the disease itself or as a consequence of medications used to treat the rheumatic diseases. There is an increasing body of evidence investigating the role of PET scans in inflammatory conditions. This paper describes a patient with rheumatoid arthritis who developed pulmonary nodules that showed increased uptake on PET/CT scan and reviews the use of PET scanning in the diagnosis and management of rheumatoid arthritis.
Fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been approved for imaging in many malignancies but not for bladder cancer. This study investigated the value of FDG-PET/CT imaging in the management of patients with advanced bladder cancer.
Patients and Methods
Between May 2006 and February 2008, 57 patients with bladder cancer at our center underwent FDG-PET/CT after CT (n = 52) or magnetic resonance imaging (MRI; n = 5). The accuracy of FDG-PET/CT was assessed using both organ-based and patient-based analyses. FDG-PET/CT findings were validated by either biopsy or serial CT/MRI. Clinician questionnaires performed before and after FDG-PET/CT assessed whether those scan results affected management.
One hundred thirty-five individual lesions were evaluable in 47 patients for the organ-based analysis. Overall sensitivity and specificity were 87% (95% CI, 76% to 94%) and 88% (95% CI, 78% to 95%), respectively. In the patient-based analysis, malignant disease was correctly diagnosed in 25 of 31 patients, resulting in a sensitivity of 81% (95% CI, 63% to 93%). FDG-PET/CT was negative in 15 of 16 patients without malignant lesions for a specificity of 94% (95% CI, 71% to 100%). Pre- and post-PET surveys revealed that FDG-PET/CT detected more malignant disease than conventional CT/MRI in 40% of patients. Post-PET surveys showed that clinicians changed their planned management in 68% of patients based on the FDG-PET/CT results.
FDG-PET/CT has excellent sensitivity and specificity in the detection of metastatic bladder cancer and provides additional diagnostic information that enhances clinical management more than CT/MRI alone. FDG-PET/CT scans may provide better accuracy in clinical information for directing therapy.
Recent data confirmed the importance of 18-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) in the selection of patients with colorectal hepatic metastases for surgery. Neoadjuvant chemotherapy before hepatic resection in selected cases may improve outcome. The influence of chemotherapy on the sensitivity of FDG-PET and CT in detecting liver metastases is not known.
Patients were assigned to either neoadjuvant treatment or immediate hepatic resection according to resectability, risk of recurrence, extrahepatic disease, and patient preference. Two-thirds of them underwent FDG-PET/CT before chemotherapy; all underwent preoperative contrast-enhanced CT and FDG-PET/CT. Those without extensive extrahepatic disease underwent open exploration and resection of all the metastases according to original imaging findings. Operative and pathological findings were compared to imaging results.
Twenty-seven patients (33 lesions) underwent immediate hepatic resection (group 1), and 48 patients (122 lesions) received preoperative neoadjuvant chemotherapy (group 2). Sensitivity of FDG-PET and CT in detecting colorectal (CR) metastases was significantly higher in group 1 than in group 2 (FDG-PET: 93.3 vs 49%, P < 0.0001; CT: 87.5 vs 65.3, P = 0.038). CT had a higher sensitivity than FDG-PET in detecting CR metastases following neoadjuvant therapy (65.3 vs 49%, P < 0.0001). Sensitivity of FDG-PET, but not of CT, was lower in group 2 patients whose chemotherapy included bevacizumab compared to patients who did not receive bevacizumab (39 vs 59%, P = 0.068).
FDG-PET/CT sensitivity is lowered by neoadjuvant chemotherapy. CT is more sensitive than FDG-PET in detecting CR metastases following neoadjuvant therapy. Surgical decision-making requires information from multiple imaging modalities and pretreatment findings. Baseline FDG-PET and CT before neoadjuvant therapy are mandatory.
Colorectal liver metastases; FDG-PET; Neoadjuvant chemotherapy
In cardiac 2-[F-18]fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET) examination, interpretation of myocardial viability in the low uptake region (LUR) has been difficult without additional perfusion imaging. We evaluated distribution patterns of FDG at the border zone of the LUR in the cardiac FDG-PET and established a novel parameter for diagnosing myocardial viability and for discriminating the LUR of normal variants.
Materials and Methods
Cardiac FDG-PET was performed in patients with a myocardial ischemic event (n = 22) and in healthy volunteers (n = 22). Whether the myocardium was not a viable myocardium (not-VM) or an ischemic but viable myocardium (isch-VM) was defined by an echocardiogram under a low dose of dobutamine infusion as the gold standard. FDG images were displayed as gray scaled-bull's eye mappings. FDG-plot profiles for LUR (= true ischemic region in the patients or normal variant region in healthy subjects) were calculated. Maximal values of FDG change at the LUR border zone (a steepness index; Smax scale/pixel) were compared among not-VM, isch-VM, and normal myocardium.
Smax was significantly higher for n-VM compared to those with isch-VM or normal myocardium (ANOVA). A cut-off value of 0.30 in Smax demonstrated 100% sensitivity and 83% specificity for diagnosing n-VM and isch-VM. Smax less than 0.23 discriminated LUR in normal myocardium from the LUR in patients with both n-VM and isch-VM with a 94% sensitivity and a 93% specificity.
Smax of the LUR in cardiac FDG-PET is a simple and useful parameter to diagnose n-VM and isch-VM, as well as to discriminate thr LUR of normal variants.
Fluorodeoxyglucose; myocardial infarction; organ viability; image processing; echocardiography
We report the findings of [18F] fluoro-deoxy-glucose (FDG) positron emission tomography (PET) performed in a 67-year-old female with suspicion of gastric carcinoma. Intense FDG uptake was noted in the thickened gastric wall. Subsequent laparotomy showed diffuse involvement of the gastric wall by signet ring cell adenocarcinoma. This report highlights FDG PET/CT pattern in linitis plastica of the stomach caused by primary signet cell adenocarcinoma.
F-18 FDG; linitis plastica; PET/CT; stomach cancer
To assess the impact on clinical management of introducing 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)-computed tomography (CT) in to the work-up of patients with primary and recurrent biliary malignancy.
Consecutive patients with primary biliary tumours undergoing FDG PET-CT at a single large tertiary referral centre between November 2007 and September 2010 were retrospectively analysed. Findings on FDG PET-CT compared with CT/magnetic resonance imaging (MRI) and impact on subsequent patient management were evaluated. Impact was divided into: (1) major—detection of occult disease or characterisation of indeterminate lesion(s) on CT/MRI; (2) minor—confirmation of suspected metastases seen on CT/MRI; (3) no impact.
One hundred and eleven patients underwent 118 FDG PET-CT scans, including 30 with suspected gallbladder carcinoma and 81 with cholangiocarcinoma. Eighty-nine scans were performed for initial staging, five for restaging following neoadjuvant chemotherapy and 24 for suspected disease recurrence. In 33 cases (28 %), FDG PET-CT had a major impact on subsequent patient management (39 % gallbladder carcinoma, 26 % intrahepatic cholangiocarcinoma and 21 % extrahepatic cholangiocarcinoma). FDG PET-CT had a minor impact in 20 cases (17 %) and no impact in 65 cases (55 %).
By detecting occult metastatic disease and characterising indeterminate lesions, FDG PET-CT can have a major influence on clinical decision-making in primary and recurrent biliary malignancy.
Gallbladder carcinoma; Cholangiocarcinoma; Biliary tumours; 18F-fluoro-2-deoxy-D-glucose positron emission tomography-computed tomography
Cancer of unknown primary origin (CUP) is an aggressive disease with a poor prognosis. Metastatic brain tumors occur in approximately 15% of all cancer patients. F-18 2′-deoxy-2fluoro-D-glucose (FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) contributes to the evaluation of cancer staging, although the benefits of PET/CT for detection of CUP origins has yet to be determined. In this study, we present a 37-year-old man with a brain tumor detected by magnetic resonance imaging. Surgical biopsy indicated a metastatic undifferentiated carcinoma, while clinical examination and a CT scan did not detect any abnormalities, with the exception of brain metastases. PET/CT did not reveal abnormal FDG uptake. PET/CT revealed abnormal intense FDG uptake in a small nodular lesion in the right lung 1 year following the detection of brain metastasis, and no other abnormal FDG uptake was observed elsewhere in the body. Right upper lobectomy and dissection of mediastinal lymph nodes were performed. The pathological diagnosis was poorly differentiated adenocarcinoma, which was similar to the brain metastatic lesion, and there was no lymph node metastasis. This case revealed an extremely rare lung cancer with primary lesions demonstrated by PET/CT 1 year after the detection of brain metastasis. This case reveals that F-18 FDG PET/CT imaging of CUP origin is capable of positively impacting on the identification of small primary tumor foci.
PET/CT; metastatic brain tumor; lung cancer; unknown primary origin
Previous positron emission tomography (PET) studies have shown increased 2-deoxy-2-[18F]fluoro-d-glucose (FDG) uptake in joints of patients with osteoarthritis (OA) and inflamed joints of patients with rheumatoid arthritis (RA). This study compares FDG uptake in joints of RA and OA patients and FDG-uptake with clinical signs of inflammation.
FDG-PET scans of hands and wrists were performed in patients with RA and primary OA. PET data were compared with clinical data.
29% of RA joints and 6% of OA joints showed elevated FDG-uptake. The level of uptake in PET-positive OA joints was not significantly different from that in RA joints. The majority of PET results of RA joints corresponded with clinical findings. Clinical synovitis was found some OA joints with FDG-uptake.
FDG-uptake was observed in the majority of clinically inflamed RA joints and in a few OA joints with no significant difference in uptake level. The latter may be due to secondary synovitis.
FDG; Rheumatology; Rheumatoid arthritis; Osteoarthritis
There has been an increase in the detection rate of small early lung cancer due to recent improvements in imaging technology. However, conventional imaging modalities such as computed tomography (CT) alone are not capable of differentiating small pulmonary nodules. New modalities such as F-18 2′-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with CT (PET/CT) have contributed to the evaluation of lung cancer staging, although the differential diagnosis of pulmonary nodules showing ground-glass opacity (GGO) with PET/CT is controversial. In Japan, cancer screening with whole body FDG-PET has been available for asymptomatic individuals, and it has been reported that a wide variety of cancer types are detectable by FDG-PET at potentially curable stages. We present the case of a 62-year-old male with early lung cancer, which was revealed by repeated health screening. A PET/CT scan revealed definite intense FDG uptake (SUVmax 1.2) in the pulmonary nodules of the right upper lobe, while no definite FDG uptake was observed in the lesion in the previous annual screening. Right upper lobectomy was performed, and the pathological diagnosis was well-differentiated adenocarcinoma. Five-year survival has been noted since the thoracotomy, and the patient is doing well without recurrence. This is a significant case of early lung cancer with GGO lesions, which revealed intense FDG uptake during an annual repeated health screening with FDG-PET/CT.
lung cancer; positron emission tomography/computed tomography; screening; ground-glass opacity
We proposed that metabolic remodeling in the form of increased myocardial glucose analogue 2-[18F] fluoro-2deoxy-D-glucose (FDG) uptake precedes and triggers the onset of severe contractile dysfunction in pressure overload left ventricular hypertrophy (LVH) in vivo. To test this hypothesis we used a mouse model of transverse aortic constriction (TAC) together with Positron Emission Tomography (PET) and assessed serial changes in cardiac metabolism and function over 7 days.
PET scans of 16 C57BL/6 male mice were performed using a microPET scanner under sevofluorane anesthesia. A 10-minute transmission scan was followed by a 60-minute dynamic FDG-PET scan with cardiac and respiratory gating. Blood glucose levels were measured before and after the emission scan. Transverse aortic constriction (TAC) and sham surgeries were performed after baseline imaging. Osmotic mini-pumps containing either propranolol (5 mg/kg/day) or vehicle alone were implanted subcutaneously at the end of surgery. Subsequent scans were taken at days 1 and 7 after surgery. A compartment model, in which the blood input function with spill-over and partial volume corrections and the metabolic rate constants in a 3-compartment model are simultaneously estimated, was used to determine the net myocardial FDG influx constant, Ki. The rate of myocardial glucose use, rMGU, was also computed. Estimations of the ejection fractions (EF) were based on the high resolution gated PET images
Mice undergoing TAC surgery exhibited an increase in the Ki (580%) and glucose usage the day after surgery indicating early adaptive response. On day 7 the EF had decreased by 24% indicating a maladaptive response. Average Ki increases were not linearly associated with increases in rMGU. Ki exceeded rMGU by 29% in the TAC mice. TAC Mice treated with propranolol attenuated rate of FDG uptake, diminished mismatch between Ki and rMGU (9%) and rescued cardiac function.
Metabolic maladaptation precedes the onset of severe contractile dysfunction. Both are prevented by treatment with propranolol. Early detection of metabolic remodeling may offer a metabolic target for modulation of hypertrophy.
FDG-PET; Glucose Metabolism in Heart; Left Ventricular Ejection Fraction; Left Ventricular Hypertrophy
Nuclear medicine imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) have played a prominent role in lymphoma management. PET with [18F]Fluoro-2-deoxy-D-glucose (FDG) is the most commonly used tool for lymphoma imaging. However, FDG-PET has several limitations that give the false positive or false negative diagnosis of lymphoma. Therefore, development of new radiotracers with higher sensitivity, specificity, and different uptake mechanism is in great demand in the management of lymphoma. This paper reviews non-FDG radiopharmaceuticals that have been applied for PET and SPECT imaging in patients with different types of lymphoma, with attention to diagnosis, staging, therapy response assessment, and surveillance for disease relapse. In addition, we introduce three radiolabeled anti-CD20 antibodies for radioimmunotherapy, which is another important arm for lymphoma treatment and management. Finally, the relatively promising radiotracers that are currently under preclinical development are also discussed in this paper.
One of the main features of Alzheimer’s disease (AD) is the severe reduction of the cerebral metabolic rate for glucose (CMRglc). In vivo imaging using positron emission tomography with 2-[18F]fluoro-2-deoxy-D-glucose (FDG–PET) demonstrates consistent and progressive CMRglc reductions in AD patients, the extent and topography of which correlate with symptom severity. Increasing evidence suggests that CMRglc reductions occur at the preclinical stages of AD. CMRglc reductions were observed on FDG–PET before the onset of disease in several groups of at-risk individuals, including patients with mild cognitive impairment (MCI), often a prodrome to AD; presymptomatic individuals carrying mutations responsible for early-onset familial AD; cognitively normal elderly individuals followed for several years until they declined to MCI and eventually to AD; normal, middle-aged individuals who expressed subjective memory complaints and were carriers of the apolipoprotein E epsilon-4 allele, a strong genetic risk factor for late-onset AD. However, the causes of the early metabolic dysfunction forerunning the onset of AD are not known. An increasing body of evidence indicates a deficient or altered energy metabolism that could change the overall oxidative microenvironment for neurons during the pathogenesis and progression of AD, leading to alterations in mitochondrial enzymes and in glucose metabolism in AD brain tissue. The present paper reviews findings that implicate hypometabolism and oxidative stress as crucial players in the initiation and progression of synaptic pathology in AD.
FDG; PET; Alzheimer’s disease; hypometabolism; oxidative stress; preclinical; early diagnosis
Functional imaging studies report that higher education is associated with more severe pathology in patients with Alzheimer's disease, controlling for disease severity. Therefore, schooling seems to provide brain reserve against neurodegeneration.
To provide further evidence for brain reserve in a large sample, using a sensitive technique for the indirect assessment of brain abnormality (18F‐fluoro‐deoxy‐glucose‐positron emission tomography (FDG‐PET)), a comprehensive measure of global cognitive impairment to control for disease severity (total score of the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Battery) and an approach unbiased by predefined regions of interest for the statistical analysis (statistical parametric mapping (SPM)).
93 patients with mild Alzheimer's disease and 16 healthy controls underwent 18F‐FDG‐PET imaging of the brain. A linear regression analysis with education as independent and glucose utilisation as dependent variables, adjusted for global cognitive status and demographic variables, was conducted in SPM2.
The regression analysis showed a marked inverse association between years of schooling and glucose metabolism in the posterior temporo‐occipital association cortex and the precuneus in the left hemisphere.
In line with previous reports, the findings suggest that education is associated with brain reserve and that people with higher education can cope with brain damage for a longer time.
The purpose of this study is to assess treatment responses induced by the two tyrosine kinase inhibitors, Imatinib and Sunitinib, in a gastrointestinal stromal tumor (GIST) xenograft using a clinical positron emission tomography/computed tomography (PET/CT) scanner.
Nude mice bearing human GIST xenografts with mutations in exons 11 and 17 were randomly allocated to treatment with Imatinib, Sunitinib, or placebo daily for seven consecutive days. 2-deoxy-2-[18F]fluoro-d-glucose PET (18F-FDG-PET/CT) was performed in a clinical PET/CT scanner at baseline (day 0) and 1 and 7 days after onset of treatment. Treatment response was assessed by measuring tumor volumes and by calculation of tumor-to-liver 18F-FDG uptake ratios.
Minor reductions in tumor volume were observed in both treatment groups. For the two treatment groups, significantly decreased tumor-to-liver uptake ratios were observed both at day 1 (Imatinib, −41%, p = .002; Sunitinib, −55%, p < .001) and at day 8 (Imatinib, −35%, p < .001; Sunitinib, −50%, p < .001), when compared to individual baseline values. For the control tumors, neither tumor volumes nor tumor-to-liver uptake ratios were altered during the 8 days the experiment lasted.
Significant anti-tumor effects were demonstrated following treatment with both Imatinib and Sunitinib. Decreased tumor-to-liver uptake ratios were more pronounced than tumor volume reductions. Effects of novel targeted therapies can be evaluated in the GIST xenograft model using a clinical PET/CT scanner.
GIST xenograft; AHAX; Imatinib; Sunitinib; Clinical PET/CT scanner
The role of positron emission tomography (PET) with fluoro-deoxy-glucose (FDG) in the staging of head and neck cancer (HNC) is unclear. The NCCN guidelines do not recommend FDG-PET as a part of standard workup. The purpose of this report is to examine the role of FDG-PET imaging in altering management and providing prognostic information for HNC.
Retrospective review of HNC patients who had a staging FDG-PET scan performed at either Thomas Jefferson University or University of Kansas Medical Center between the years 2001 and 2007. A total of 212 PET scans were performed in patients who went on to receive radiotherapy.
The median follow-up time for all patients was 469 days. The PPV and NPV of PET imaging to correctly identify lymph node status was 94% and 89% respectively. Lymph nodes with extracapsular extension (ECE) had higher SUVs than nodes without ECE, 11.0 vs. 5.0 (p < 0.0007). Maximum SUV for the primary tumor > 8.0 was predictive of worse overall survival (p < 0.045), while the SUV of the lymph nodes was predictive for distant recurrence at one year--with a mean SUV value of 10.4 for patients with distant failure vs. 7.0 without (p < 0.05).
FDG-PET staging in head and neck cancer has good positive and negative predictive values in determining lymph node status. The maximum SUV of the primary tumor is predictive of overall survival. This is the first report to find that the SUV of a lymph node is predictive for ECE and also for distant recurrence.
The aim of this study was to evaluate the diagnostic accuracy of fused fluoro-deoxy-D-glucose positron emission tomography/magnetic resonance mammography (FDG-PET/MRM) in breast cancer patients and to compare FDG-PET/MRM with MRM.
27 breast cancer patients (mean age 58.9±9.9 years) underwent MRM and prone FDG-PET. Images were fused software-based to FDG-PET/MRM images. Histopathology served as the reference standard to define the following parameters for both MRM and FDG-PET/MRM: sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for the detection of breast cancer lesions. Furthermore, the number of patients with correctly determined lesion focality was assessed. Differences between both modalities were assessed by McNemaŕs test (p<0.05). The number of patients in whom FDG-PET/MRM would have changed the surgical approach was determined.
58 breast lesions were evaluated. The sensitivity, specificity, PPV, NPV and accuracy were 93%, 60%, 87%, 75% and 85% for MRM, respectively. For FDG-PET/MRM they were 88%, 73%, 90%, 69% and 92%, respectively. FDG-PET/MRM was as accurate for lesion detection (p = 1) and determination of the lesions' focality (p = 0.7722) as MRM. In only 1 patient FDG-PET/MRM would have changed the surgical treatment.
FDG-PET/MRM is as accurate as MRM for the evaluation of local breast cancer. FDG-PET/MRM defines the tumours' focality as accurately as MRM and may have an impact on the surgical treatment in only a small portion of patients. Based on these results, FDG-PET/MRM cannot be recommended as an adjunct or alternative to MRM.