Relationship Between the Size of Metastatic Lymph Nodes and Positron Emission Tomographic/Computer Tomographic Findings in Patients with Esophageal Squamous Cell Carcinoma.

BACKGROUND: We measured the sizes of metastatic lymph nodes and the relationships thereof by (18)F-fluorodeoxyglucose positron emission tomography/computer tomography (PET/CT). We identified risk factors for nodal upstaging in patients with esophageal squamous cell carcinoma (ESCC). METHODS: Eighty-five patients with ESCC who underwent esophagectomy with extensive mediastinal lymphadenectomy were assessed. Two radiologists blinded to pathology data reviewed PET/CT scans, evaluating both primary tumors and lymph node involvement. A pathologist examined all metastatic lymph nodes in terms of maximal diameter (LNmax), the size of the metastatic focus (Fmax), and the metastasis occupation ratio (MOR = Fmax/LNmax). RESULTS: The maximal tumor length averaged 2.9 ± 0.2 cm and the mean SUVmax of the primary lesion 5.3 ± 0.5. On PET/CT scans, 26 (30.6 %) patients exhibited nodal metastasis and 59 (69.4 %) did not. Pathology grades of pN0, pN1, pN2, and pN3 were assigned to 45 (52.9 %), 24 (28.2 %), 13 (15.3 %), and 3 (3.5 %) patients, respectively. Nodal upstaging was evident in 29 (34.1 %) cases. In 123 metastatic nodes of 4212 nodes dissected, the LNmax was 6.60 ± 0.39 mm, the Fmax 4.47 ± 0.35 mm, and the MOR 0.68 ± 0.03. Of 123 nodes, 85 (69.1 %) were retrieved from PET-negative stations, and the LNmax and Fmax values of these nodes were 5.88 ± 0.42 and 3.75 ± 0.31 mm, respectively. Upon multivariate analysis, tumor length (OR 1.666, p = 0.019) and lymphovascular invasion (OR 41.038, p < 0.001) were risk factors for nodal upstaging. CONCLUSION: A significant proportion of nodal metastases were too small to detect via PET/CT imaging. Therefore, meticulous lymph node dissection might be helpful in ESCC patients.

Predictive value of pretreatment metabolic activity measured by fluorodeoxyglucose positron emission tomography in patients with metastatic advanced gastric cancer: the maximal SUV of the stomach is a prognostic factor.

PURPOSE: Few studies have evaluated metabolic activity by (18)F-FDG PET as a prognostic factor in advanced gastric cancer (AGC). We investigated its prognostic role in metastatic AGC. METHODS: We enrolled 82 patients with metastatic AGC, who were treatment-naive and underwent pretreatment (18)F-FDG PET/CT scanning. In each patient, the maximal standardized uptake value (SUVmax) was measured in each target lesion. Stomach(SUVmax) was defined as SUVmax in the stomach, while Total(SUVmax) was defined as the highest SUVmax among all the target lesions. RESULTS: The stomach was the organ most frequently displaying the highest SUVmax among all the target lesions (in 67.1% of patients). A Total(SUVmax) value of 11.5 was the value with the maximum sum of sensitivity and specificity from receiver-operating characteristic curves for progression-free survival (PFS). PFS was significantly longer in patients with a Total(SUVmax) value <11.5 than in those with a Total(SUVmax) value ≥11.5 (P = 0.023); however, overall survival (OS) was not (P = 0.055). A Stomach(SUVmax) value of 6.0 was derived by similar methods. PFS and OS were significantly longer in those with a Stomach(SUVmax) value <6.0 than in those with a Stomach(SUVmax) value ≥6.0 (P = 0.001 and P = 0.006, respectively). Furthermore, those with a low Total(SUVmax) and those with a low Stomach(SUVmax) showed better chemotherapeutic responses (P = 0.016 and P = 0.034, respectively). Among patients with histologically undifferentiated carcinomas, those with lower Total(SUVmax) and those with lower Stomach(SUVmax) showed longer median PFS (P = 0.027 and P = 0.005, respectively) and OS (P = 0.009 and P <0.001, respectively). Multivariate analysis demonstrated Stomach(SUVmax) as an independent predictor of PFS (P = 0.002) and OS (P = 0.038). CONCLUSION: Pretreatment metabolic activity may be a useful prognostic marker in patients with metastatic AGC undergoing palliative chemotherapy. Notably, Stomach(SUVmax) was the single, most robust factor predicting prognosis.

Androgen stimulates glycolysis for de novo lipid synthesis by increasing the activities of hexokinase 2 and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 2 in prostate cancer cells.

Up-regulation of lipogenesis by androgen is one of the most characteristic metabolic features of LNCaP prostate cancer cells. The present study revealed that androgen increases glucose utilization for de novo lipogenesis in LNCaP cells through the activation of HK2 (hexokinase 2) and activation of the cardiac isoform of PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase). Activation of PKA (cAMP-dependent protein kinase) by androgen increased phosphorylation of CREB [CRE (cAMP-response element)-binding protein], which in turn bound to CRE on the promoter of the HK2 gene resulting in transcriptional activation of the HK2 gene. Up-regulation of PFKFB2 expression was mediated by the direct binding of ligand-activated androgen receptor to the PFKFB2 promoter. The activated PI3K (phosphoinositide 3-kinase)/Akt signalling pathway in LNCaP cells contributes to the phosphorylation of PFKFB2 at Ser466 and Ser483, resulting in the constitutive activation of PFK-2 (6-phosphofructo-2-kinase) activity. Glucose uptake and lipogenesis were severely blocked by knocking-down of PFKFB2 using siRNA (small interfering RNA) or by inhibition of PFK-2 activity with LY294002 treatment. Taken together, our results suggest that the induction of de novo lipid synthesis by androgen requires the transcriptional up-regulation of HK2 and PFKFB2, and phosphorylation of PFKFB2 generated by the PI3K/Akt signalling pathway to supply the source for lipogenesis from glucose in prostate cancer cells.

Deep learning-based amyloid PET positivity classification model in the Alzheimer's disease continuum by using 2-[18F]FDG PET.

BACKGROUND: Considering the limited accessibility of amyloid position emission tomography (PET) in patients with dementia, we proposed a deep learning (DL)-based amyloid PET positivity classification model from PET images with 2-deoxy-2-[fluorine-18]fluoro-D-glucose (2-[18F]FDG). METHODS: We used 2-[18F]FDG PET datasets from the Alzheimer's Disease Neuroimaging Initiative and Korean Brain Aging Study for the Early diagnosis and prediction of Alzheimer's disease for model development. Moreover, we used an independent dataset from another hospital. A 2.5-D deep learning architecture was constructed using 291 submodules and three axes images as the input. We conducted the voxel-wise analysis to assess the regions with substantial differences in glucose metabolism between the amyloid PET-positive and PET-negative participants. This facilitated an understanding of the deep model classification. In addition, we compared these regions with the classification probability from the submodules. RESULTS: There were 686 out of 1433 (47.9%) and 50 out of 100 (50%) amyloid PET-positive participants in the training and internal validation datasets and the external validation datasets, respectively. With 50 times iterations of model training and validation, the model achieved an AUC of 0.811 (95% confidence interval (CI) of 0.803-0.819) and 0.798 (95% CI, 0.789-0.807) on the internal and external validation datasets, respectively. The area under the curve (AUC) was 0.860 when tested with the model with the highest value (0.864) on the external validation dataset. Moreover, it had 75.0% accuracy, 76.0% sensitivity, 74.0% specificity, and 75.0% F1-score. We found an overlap between the regions within the default mode network, thus generating high classification values. CONCLUSION: The proposed model based on the 2-[18F]FDG PET imaging data and a DL framework might successfully classify amyloid PET positivity in clinical practice, without performing amyloid PET, which have limited accessibility.

Diagnosis and staging of primary ovarian cancer: correlation between PET/CT, Doppler US, and CT or MRI.

PURPOSE: To compare the diagnostic accuracy of positron emission tomography/computed tomography (PET/CT), pelvic Doppler ultrasonography (US), abdomino-pelvic computed tomography (CT), and pelvic magnetic resonance imaging (MRI) for detection of ovarian cancer and to assess the role of PET/CT in evaluating the dissemination of ovarian cancer. PATIENTS AND METHODS: One hundred thirty-three women suspected to have ovarian cancer were enrolled in a prospective study before surgery between March 2005 and August 2007. The accuracy of each modality in detection of malignancy was estimated by computing the relevant areas under a receiver operating characteristics curve. Histopathologic results served as the reference standard. RESULTS: Histopathology showed benign tumors in 25 patients, borderline tumors in 13 patients, and malignant tumors in 95 patients. In distinguishing malignant/borderline from benign ovarian tumors, the accuracy of PET/CT (0.921) was higher than that of pelvis US (0.830) and abdomino-pelvic CT or pelvis MRI (0.749; P=0.013). Radiologic staging by PET/CT was concordant with surgical staging in 78% of patient and PET/CT revealed 15 (15.8%) unpredicted extra-abdominal lymph node metastasis in 95 patients with ovarian cancer. In addition, PET/CT detected new, unexpected co-existing malignant tumors in five (3.8%) cases including two thyroid tumors, two breast tumors, and one pancreatic neuroendocrine cancer. CONCLUSION: PET/CT is superior to pelvis US, abdomino-pelvic CT, and pelvic MRI for diagnosis of malignant ovarian tumors and is useful in revealing metastatic ovarian cancer and co-existing malignant tumors. Therefore, we suggest that PET/CT could be used during pre-operative evaluation of patients suspected to have ovarian cancer.

Diagnostic Value of Single-Photon Emission Computed Tomography/Computed Tomography Scans with Tc-99m HDP in Cervicogenic Headache.

A cervicogenic headache (CEH) is difficult to diagnose due to its varied pathology. We evaluated the usefulness of single-photon emission computed tomography/computed tomography (SPECT/CT) in diagnosing CEH and its interventional treatment. Retrospectively, 23 patients diagnosed with CEH between March 2016 to August 2018 were allocated to SPECT/CT (n = 11) and control (n = 12) groups. The SPECT/CT group was further stratified into SPECT/CT(+) and SPECT/CT(-) groups according to the presence of positive findings. Patients in the SPECT/CT group underwent an intra-articular injection at a radiologically verified lesion site, whereas those in the control group underwent third occipital nerve block. Clinical outcomes were evaluated with the visual analog scale (VAS), neck disability index (NDI), and global perceived effect (GPE) scale at baseline, and at one, three, and six months postoperatively. The SPECT/CT group showed less VAS, NDI, and GPE scores at six months postoperatively (2.91 ± 2.30 vs. 4.42 ± 1.62, p = 0.08; 38.00 ± 16.54 vs. 48.7 ± 12.40, p = 0.093; 2.00 ± 1.41 vs. 3.17 ± 1.11, p = 0.039). Successful responders at six months postoperatively were higher in the SPECT/CT(+) group than in the control group (75% vs. 0%). SPECT/CT can identify arthritic changes and accurately define therapeutic targets.

Pattern of urine iodine excretion with low iodine diet during preparation for radioactive iodine ablation in patients with thyroid cancer.

BACKGROUND: The optimal period of low iodine diet during preparation for radioactive iodine (RAI) ablation in an area with iodine-rich diet was investigated. METHODS: Ninety-four patients with thyroid cancer who underwent low iodine diet and RAI were prospectively allocated into 2 groups-thyroxine withdrawal or using recombinant human thyroid stimulating hormone (rhTSH) for TSH stimulation. Their urinary iodine excretion (UIE) patterns were analyzed. RESULTS: There was no clinicopathological difference between the 2 groups except for tumor size and lymph node status. The UIE (median iodine to creatinine ratio, I/Cr) in the withdrawal group on the 7th and 14th day were 18.3 and 17.9 µg/gCr, respectively, with adequate preparation rate of 93.3% on both days (cutoff value 100 µg/gCr). In the rhTSH group, the median I/Cr on the 7th and 14th day were 48.0 and 45.7 µg/gCr (adequate preparation rates 91.8% and 93.8%), respectively. CONCLUSION: One week of low iodine diet is sufficient preparation for RAI regardless of method of TSH stimulation.

Potential Utility of FDG PET-CT as a Non-invasive Tool for Monitoring Local Immune Responses.

PURPOSE: The tumor microenvironment is known to be associated with the metabolic activity of cancer cells and local immune reactions. We hypothesized that glucose metabolism measured by 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) positron emission tomography (PET)-computed tomography (CT) (18F-FDG PET-CT) would be associated with local immune responses evaluated according to the presence of tumor infiltrating lymphocytes (TILs). MATERIALS AND METHODS: We retrospectively reviewed 56 patients who underwent 18F-FDG PET-CT prior to gastrectomy. In resected tumor specimens, TIL subsets, including cluster of differentiation (CD) 3, CD4, CD8, Forkhead box P3 (Foxp3), and granzyme B, were subjected to immunohistochemical analysis. The prognostic nutritional index (PNI) was calculated as: (10×serum albumin value)+(0.005×peripheral lymphocyte counts). Additionally, the maximum standard uptake value (SUVmax) was calculated to evaluate the metabolic activity of cancer cells. RESULTS: The SUVmax was positively correlated with larger tumor size (R=0.293; P=0.029) and negatively correlated with PNI (R=-0.407; P=0.002). A higher SUVmax showed a marginal association with higher CD3 (+) T lymphocyte counts (R=0.227; P=0.092) and a significant association with higher Foxp3 (+) T lymphocyte counts (R=0.431; P=0.009). No other clinicopathological characteristics were associated with SUVmax or TILs. Survival analysis, however, indicated that neither SUVmax nor Foxp3 held prognostic significance. CONCLUSIONS: FDG uptake on PET-CT could be associated with TILs, especially regulatory T cells, in gastric cancer. This finding may suggest that PET-CT could be of use as a non-invasive tool for monitoring the tumor microenvironment in patients with gastric cancer.

CT and PET in stomach cancer: preoperative staging and monitoring of response to therapy.

Stomach cancer is one of the leading causes of cancer mortality worldwide. Complete resection of a gastric tumor and adjacent lymph nodes represents the only potentially curative intervention. Computed tomography (CT) has remained the modality of choice for the preoperative staging of gastric cancer and for follow-up. A recently developed advanced CT technique that makes use of thin sections, optimal contrast material enhancement, and multiplanar reformation allows more accurate staging. However, CT may be limited in the identification of nonenlarged lymph node metastasis, peritoneal dissemination, and small hematogenous metastasis. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) has been recognized as a useful diagnostic technique in clinical oncology. FDG PET allows scanning of a larger volume than is possible with CT. Although FDG PET is not an appropriate first-line diagnostic procedure in the detection of stomach cancer and is not helpful in tumor staging, it may play a valuable role in the detection of distant metastases, such as those of the liver, lungs, adrenal glands, ovaries, and skeleton. FDG PET may also be helpful in the follow-up of patients undergoing chemotherapy, as it allows the identification of early response to treatment. Further studies are needed to determine the efficacy of FDG PET in the detection of local nodal metastases and peritoneal dissemination. Nevertheless, the combined use of CT and PET can be helpful in the preoperative staging of stomach cancer and in the therapeutic monitoring of affected patients.

Comparison of CT and 18F-FDG pet for detecting peritoneal metastasis on the preoperative evaluation for gastric carcinoma.

OBJECTIVE: The aim of our study was to compare the accuracy of CT and (18)FFDG PET for detecting peritoneal metastasis in patients with gastric carcinoma. MATERIALS AND METHODS: One-hundred-twelve patients who underwent a histologic confirmative exam or treatment (laparotomy, n = 107; diagnostic laparoscopy, n = 4; peritoneal washing cytology, n = 1) were retrospectively enrolled. All the patients underwent CT and (18)F-FDG PET scanning for their preoperative evaluation. The sensitivities, specificities and accuracies of CT and (18)FFDG PET imaging for the detection of peritoneal metastasis were calculated and then compared using Fisher's exact probability test (p < 0.05), on the basis of the original preoperative reports. In addition, two board-certified radiologists and two board-certified nuclear medicine physicians independently reviewed the CT and PET scans, respectively. A receiver-operating characteristic curve analysis was performed to compare the diagnostic performance of CT and (18)F-FDG PET imaging for detecting peritoneal metastasis. RESULTS: Based on the original preoperative reports, CT and (18)F-FDG PET showed sensitivities of 76.5% and 35.3% (p = 0.037), specificities of 91.6% and 98.9% (p = 0.035), respectively, and equal accuracies of 89.3% (p = 1.0). The receptor operating characteristics curve analysis showed a significantly higher diagnostic performance for CT (Az = 0.878) than for PET (Az = 0.686) (p = 0.004). The interobserver agreement for detecting peritoneal metastasis was good (kappa value = 0.684) for CT and moderate (kappa value = 0.460) for PET. CONCLUSION: For the detection of peritoneal metastasis, CT was more sensitive and showed a higher diagnostic performance than PET, although CT had a relatively lower specificity than did PET.

A systemic lupus erythematosus patient with protein losing enteropathy.

Protein-losing enteropathy (PLE) is a rare manifestation of systemic lupus erythematosus (SLE), and it is an uncommon cause of hypoalbuminemia without proteinuria. We describe a case of an 11 year-old girl who had diarrhea and periorbital edema as the initial symptoms of SLE. PLE was diagnosed by 24-hour stool alpha-1 antitrypsin clearance and (99m)Tc-human serum albumin scintigraphy.

Quantitative analysis of simultaneous EEG features during PET studies for childhood partial epilepsy.

PURPOSE: To demonstrate the significance of simultaneous electroencephalography (EEG) recording during 2-deoxy-2-[(18)F] fluoro-D-glucose (FDG)-positron emission tomography (PET) in childhood partial epilepsy. MATERIALS AND METHODS: We included 46 children with partial epilepsy who underwent simultaneous EEG during PET. We compared the epileptogenic area of several EEG features including epileptiform discharges, focal polymorphic slow waves, and electrographic seizures, with the abnormal metabolic region on PET. We also compared the epileptogenic area of simultaneous EEG and PET with findings on magnetic resonance imaging (MRI) and video/EEG, as well as the histopathological diagnosis of the resected cortical area, in eight patients who underwent surgical resection of the epileptogenic area. RESULTS: Hypometabolic regions on interictal PET were concordant with epileptogenic areas of epileptiform discharges and focal polymorphic slow waves, according to their frequency and/or severity, with odds ratios of 1.35 and 1.81, respectively (p<0.05). Hypermetabolic PET was also concordant with epileptogenic areas of ictal events longer than 20 seconds during the period of FDG uptake. Among the eight patients who underwent surgical resection, six patients, including two with non-lesional MRI, had concordant EEG and PET findings, were confirmed pathologically, and became seizure-free after surgery. CONCLUSION: Simultaneous EEG is useful in identifying epileptogenic areas due to a high concordance with abnormal PET metabolic areas. Moreover, simultaneous EEG may also prevent false lateralization of PET from postictal and mixed metabolism during ictal events, as well as abnormal hypermetabolism, during frequent interictal epileptiform discharges.

Analysis of 18F-fluorodeoxyglucose positron emission tomography findings in patients with pituitary lesions.

BACKGROUND/AIMS: Although magnetic resonance imaging (MRI) is a good visual modality for the evaluation of pituitary lesions, it has limited value in the diagnosis of mixed nodules and some cystic lesions. We evaluated the usefulness of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) for patients with pituitary lesions. METHODS: (18)F-FDG PET and MRI were performed simultaneously in 32 consecutive patients with pituitary lesions. The relationships between FDG uptake patterns in PET and MRI findings were analyzed. RESULTS: Of 24 patients with piuitary adenomas, 19 (79.2%) showed increased uptake of (18)F-FDG in the pituitary gland on PET scans. All patients with pituitary macroadenomas showed increased (18)F-FDG uptake on PET scans. Meanwhile, only five (50%) of the 10 patients with pituitary microadenomas showed positive PET scans. Interestingly, of two patients with no abnormal MRI findings, one showed increased (18)F-FDG uptake on PET. For positive (18)F-FDG uptake, maximum standardized uptake values (SUV(max)) > 2.4 had 94.7% sensitivity and 100% specificity. In addition, SUV(max) increased in proportion to the size of pituitary adenomas. Most cystic lesions did not show (18)F-FDG uptake on PET scans. CONCLUSIONS: About 80% of pituitary adenomas showed positivity on PET scans, and SUV(max) was related to the size of the adenomas. PET may be used as an ancillary tool for detection and differentiation of pituitary lesions.

The role of preoperative [18F]fluorodeoxyglucose positron emission tomography in predicting early recurrence after curative resection of hepatocellular carcinomas.

PURPOSE: (18)F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) scan reflects tumor differentiation and predicts clinical outcome in patients with hepatocellular carcinoma (HCC). We investigated the correlation of PET scans with tumor differentiation and early tumor recurrence (time-to-recurrence <1 year). METHODS: We reviewed the medical records of 93 patients with HCC who underwent curative resection at our hospital from August 2004 through December 2008. PET scans were performed preoperatively, and the maximum standardized uptake value of the tumor (SUV(tumor)) and the tumor-to-non-tumor SUV ratio (TNR) were calculated from FDG uptake. RESULTS: Twenty-six (27.9%) had recurrences and 12 of them (46.2%) had early recurrences. SUV(tumor) and TNR correlated strongly with tumor differentiation (p < 0.001). Early recurrence-free and the overall survival rates in the low TNR group (TNR <2.0) were higher than in the high TNR group (TNR ≥2.0) (p = 0.015, p = 0.013). According to univariate analysis, predictors of early tumor recurrence were large tumor size (≥5 cm), high TNR (≥2), high SUV(tumor) (≥4), and high Edmoson-Steiner grade. However, on multivariate analysis, none of the examined factors were statistically significant independent predictor. CONCLUSION: PET scans reflect tumor differentiation in HCCs. Because high TNR (TNR ≥2) and SUV(tumor) (SUV ≥4) were these cutoff point significant predictors in univariate analysis, future studies with more statistical power are needed to assess the significance.

Paraaortic lymph node metastasis in patients with intra-abdominal malignancies: CT vs PET.

AIM: To compare the diagnostic accuracy of computed tomography (CT) and positron emission tomography (PET) for the preoperative detection of paraaortic lymph node (PAN) metastasis in patients with intra-abdominal malignancies. METHODS: Sixty-six patients with intra-abdominal malignancies who underwent both CT and PET before lymphadenectomy were included in this study. Histopathologically, 13 patients had metastatic PAN, while 53 had non-metastatic PAN. The CT criteria for metastasis were: short diameter of > 8 mm, lobular or irregular shape, and/or combined ancillary findings, including necrosis, conglomeration, vessel encasement, and infiltration. The PET criterion was positive fluorodeoxyglucose (FDG) uptake. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of both modalities were compared with the pathologic findings, and the false positive and false negative cases with both CT and PET were analyzed. RESULTS: The sensitivity, specificity, PPV, NPV, and accuracy of CT were 61.5%, 84.9%, 50%, 90% and 80.3%, respectively. For PET, the percentages were 46.2%, 100%, 100%, 88.3%, and 89.4%. Additionally, there were 8 false positive CT cases (8/53, 15.1%) and zero false positive PET cases. Of the 13 metastatic PANs, there were 5 false negative CT scans (38.5%) and 7 (53.9%) false negative PET scans. CONCLUSION: For detecting PAN metastasis, CT is more sensitive than PET, while PET is more specific.

Efficacy of multidetector row computed tomography of the spine in patients with multiple myeloma: comparison with magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography.

PURPOSE: The aim of our study was to compare the efficacy of multidetector row computed tomography (MDCT) with magnetic resonance imaging (MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) for detection of spinal bone marrow involvement in patients with multiple myeloma. MATERIALS AND METHODS: Ten patients with multiple myeloma stage III underwent MDCT and MRI of the spine and FDG-PET. The number and location of lesions detected by 3 modalities were recorded, and a lesion-by-lesion analysis was completed, using McNemar test. For MDCT, image analysis was performed according to the type of lesion (established by Laroche et al), and the efficacy of lesion detection was compared with that of the MRI and FDG-PET. P values less than 0.05 were considered statistically significant. RESULTS: The MDCT, MRI, and FDG-PET detected the following numbers of lesions: 102 of 140 vertebrae, 95 of 140 vertebrae, and 84 of 140 vertebrae, respectively. The difference between the abilities of MDCT and MRI to detect lesions was not statistically significant (P = 0.289). However, the difference in effectiveness between MDCT and FDG-PET was statistically significant (P < 0.001). For small osteolytic lesions, less than 5 mm, the difference in effectiveness between MDCT and MRI was also statistically significant (P = 0.031). CONCLUSIONS: The MDCT is very sensitive in detecting small osteolytic lesions in the spine, as compared with MRI and FDG-PET.

Accuracy of fluorodeoxyglucose-positron emission tomography for diagnosis of single bone metastasis: comparison with bone scintigraphy.

PURPOSE: The aim of this study was to compare the accuracy of fluorodeoxyglucose-positron emission tomography (FDG-PET) with bone scan for diagnosis of single bone metastasis using a semiquantitative method. MATERIAL AND METHODS: Seventy-six patients with suspected single bone metastasis, who underwent both FDG-PET and a bone scan, were selected. The number and location of lesions detected upon both FDG-PET and bone scan were recorded, and the lesions were compared using the McNemar test. For semiquantitative analysis, a maximum (max) standard uptake value (SUV) of 2.5 was used as the positive cutoff value for metastasis. The difference in max SUV value among 3 groups (osteolytic, osteoblastic, and benign lesions) was assessed using the Student-Newman-Keuls method. Biopsy results, other imaging findings (multirow detector computed tomography, magnetic resonance imaging), and the patient's clinical course were used as references. RESULTS: There were 47 single bone metastases and 29 benign lesions. The sensitivity, specificity, and accuracy of bone scans for diagnosing bone metastases were 89%, 41%, and 71%, respectively, and those of FDG-PET were 85%, 52%, and 72%, respectively. These data were not significantly different (P > 0.05). Using a max SUV of 2.5 as the positive cutoff value for metastasis, the specificity and accuracy of FDG-PET, 83% for each, improved. When classifying bone metastasis as osteoblastic or osteolytic, the max SUV was significantly higher in osteolytic metastasis than in osteoblastic and benign lesions (P = 0.001). CONCLUSIONS: Fluorodeoxyglucose-positron emission tomography (FDG-PET) using the semiquantitative parameter SUV improves the diagnostic ability to differentiate between single bone metastases and benign lesions.

Improvement in preoperative staging of gastric adenocarcinoma with positron emission tomography.

BACKGROUND: Positron emission tomography (PET) with 18- fluorodeoxyglucose (FDG) has been used to both detect and stage a variety of malignancies. The current study examined the value of PET for preoperative staging of gastric adenocarcinoma. METHODS: Sixty-eight patients (49 males and 19 females) with gastric adenocarcinoma, who were referred for preoperative FDG-PET scans, were enrolled in this study. The patients underwent spiral-computed tomography (CT) within 1 week of referral. The final diagnosis in all patients was made by histologic and surgical findings. For quantitative PET analysis, the regional tumor FDG uptake was measured by the standardized uptake value (SUV). RESULTS: For the primary tumor of a gastric adenocarcinoma, PET demonstrated an increased uptake in 64 of 68 patients (sensitivity, 94%), with a mean SUV of 7.0 (range, 0.9-27.7). A comparison of FDG uptake and clinicopathologic features showed significant association between FDG uptake and macroscopic type, tumor size, lymph node metastasis, histologic type, and TNM stage. The PET scan had a similar accuracy with that of CT for diagnosing local and distant lymph node metastases as well as peritoneal status. In assessing local lymph node status, however, PET had a higher specificity than CT (92% vs. 62%, P = 0.000). Moreover, PET had additional diagnostic value in 10 (15%) of 68 patients by upstaging 4 (6%) and downstaging 6 (9%) patients. PET combined with CT was more accurate for preoperative staging than either modality alone (66% vs. 51%, 66% vs. 47%, respectively; P = 0.002). CONCLUSIONS: FDG-PET improves the preoperative TNM staging of gastric adenocarcinoma. Based on its superior specificity, FDG-PET can facilitate the selection of patients for a curative resection by confirming a nodal status identified by CT.