Diagnostic accuracy of FDG-PET cancer screening in asymptomatic individuals: use of record linkage from the Osaka Cancer Registry.

BACKGROUND: Whole-body cancer screening with multimodalities including [(18)F]-fluorodeoxyglucose positron emission tomography (FDG-PET) detects a wide range of tumors. This program has been recognized as an option for opportunistic screening, particularly in Japan. However, reports on diagnostic accuracy have been limited. We aimed to evaluate the detectability and related properties of this screening program among asymptomatic individuals in a community setting. METHODS: The study participants were 1,762 residents of Osaka Prefecture, Japan, who underwent opportunistic cancer screening at Higashitemma Clinic for the first time between November 2004 and December 2005. FDG-PET cancer screening was performed with several imaging modalities (e.g., FDG-PET, computed tomography, magnetic resonance imaging and ultrasonography) and fecal occult blood test. Screening records were linked to the Osaka cancer registry within 1 year after the screening to determine sensitivity, specificity and positive predictive values. RESULTS: After excluding 12 participants with cancer detected before the screening, 33 were identified by the cancer registry to have primary cancers. Of these, the present screening program found that 28 were positive (6 prostate, 5 lung, 5 colorectal, 5 thyroid, 3 liver and 4 others). Sensitivity, specificity and positive predictive values were 84.8 % (28/33, 95 % confidence interval 69.1-93.3), 86.8 % (1,491/1,718, 85.1-88.3) and 10.1 % (28/277, 6.4-12.9), respectively. CONCLUSIONS: FDG-PET cancer screening with multimodalities reasonably and accurately detects existing asymptomatic cancer. However, the numbers of false negatives and false positives were not insignificant. Facilities that provide the screening should inform participants of relevant information, including the limitations of this program.

FDG PET/CT versus CT, MR imaging, and 67Ga scintigraphy in the posttherapy evaluation of malignant lymphoma.

Malignant lymphoma is the most common form of hematologic cancer, yet because of advanced methods of assessment, the traditional histology-based classification of lymphoma is insufficient for understanding lymphoma imaging. Still, radiologists should be familiar with the imaging findings in lymphoma. Integrated positron emission tomography (PET)-computed tomography (CT) allows improved diagnostic accuracy, and uptake of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) can help predict response during treatment. The sensitivity and specificity of FDG PET are superior to those of gallium 67 scintigraphy in all but indolent lymphoma. Both magnetic resonance (MR) imaging and CT allow excellent assessment of bone texture, but FDG PET is superior in demonstrating bone marrow metabolic activity. Thus, FDG PET is important in both the primary diagnosis and the evaluation of therapy in lymphoma. It may be difficult to determine whether residual abnormalities seen after the completion of chemotherapy-radiation therapy represent residual tumor or fibrotic tissue, but PET/CT may allow more accurate diagnosis than MR imaging or CT, thereby helping identify patients who require more intensive treatment. Some diagnostic pitfalls are encountered at FDG PET. However, anatomic CT helps localize and define disease and avoid these potential pitfalls.

2-[Fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography versus whole-body diffusion-weighted MRI for detection of malignant lesions: initial experience.

OBJECTIVES: The new magnetic resonance whole body diffusion-weighted imaging with background body signal suppression (DWIBS) uses short tau inversion recovery-echo planar imaging sequence under normal respiration. DWIBS is different from 2-[fluorine-18]-fluoro-2-deoxy-D: -glucose positron emission tomography ((18)F-FDG PET) imaging in technology, but their images are similar. We compared the two modalities regarding the detection and characterization of malignant tumors. METHODS: DWIBS and (18)F-FDG PET/computed tomography (CT) were performed on 16 cancer patients on the same day. The diagnoses were the following: lung cancer (n = 12), colon cancer (n = 2), breast cancer (n = 1), and pulmonary metastasis (n = 1). A total of 27 malignant tumors (15 lung cancer, 5 pulmonary metastases of parathyroid cancer, 3 pulmonary metastases of lung cancer, 3 colon cancer, 1 breast cancer) and seven reference organs around malignant lesions (two liver regions, four normal lymph nodes, one muscle region) were evaluated visually and quantitatively using the apparent diffusion coefficient (ADC) (x10(-3) mm(2)/s) and standardized uptake value (SUV). RESULTS: Twenty-five (92.6%) of the 27 malignant lesions were detected visually with DWIBS imaging in contrast to 22 malignant tumors (81.5%) with (18)F-FDG PET/CT imaging. The quantitative evaluation showed that there was a significant difference between the mean SUVs of the reference organs (n = 7, 1.48 +/- 0.62) and the malignant (n = 22, 5.36 +/- 2.80) lesions (P < 0.01). However, there was no significant difference between the mean ADCs of the reference organs (n = 7, 1.54 +/- 0.24) and the malignant (n = 25, 1.18 +/- 0.70) lesions. CONCLUSIONS: DWIBS can be used for the detection of malignant tumors or benign tumors; however, it may be difficult to differentiate between benign and malignant lesions by ADC.

Usefulness of fully automated constant ROI analysis software for the brain: 3DSRT and FineSRT.

The positioning or selection of a region of interest (ROI) is an essential step for the quantification of brain images. However, so long as the ROIs were manually selected, results obtained fluctuated considerably with subtle changes in their positioning. To perform an ROI analysis of the brain with improved objectivity and excellent reproducibility, we recently established fully automated ROI-based analysis software for the brain, the so-called 3DSRT and the FineSRT. 3DSRT performed by consecutive analyzing process as follows: (1) anatomical standardization using the SPM99 algorithm; (2) analysis using constant 318 ROIs divided into 12 groups (segments) on each hemisphere; (3) calculation of the area-weighted average for each of the respective 24 segments; (4) display of the results followed by the saving of respective values of the 636 ROIs (both hemispheres). The processes of the FineSRT were fundamentally similar to that of 3DSRT, but on FineSRT more precise constant 1394 ROIs (both hemispheres) corresponding to the respective cerebral convolutions were used. Our programs have been useful for objective estimation of cerebrovascular reserve, especially for follow-up studies of an infant with moyamoya disease, because we could compare the results without consideration of the patient's growth during the follow-up period.

Evaluation of cingulate gyrus blood flow in patients with liver cirrhosis.

Although neuropsychological tests are commonly applied to detect minimal hepatic encephalopathy (HE) in patients with liver cirrhosis (LC), they provide no information about the cerebral regions involved. Recently, it has been reported that some populations of alcoholic cirrhotics, with mild HE, have reduced cerebral metabolic rate for glucose in bifrontal cortices and in the anterior cingulate gyrus. We evaluated the degree of reduction in blood flow at the anterior cingulate gyrus and the frontal lobes in cirrhotic patients who underwent single photon emission computed tomography (SPECT). Data were obtained from 47 cirrhotic patients and 47 subjects without LC. Three radiologists unaware of the results of laboratory tests visually evaluated the transaxial, coronal, and sagittal views of SPECT. The area and the degree of blood flow reduction in the anterior cingulate gyrus and frontal lobes were scored. Reduced blood flow in the anterior cingulate gyrus was observed in most LC patients. In patients without overt HE, poor performance in neuropsychological tests was correlated with reduced cerebral blood flow in the anterior cingulate gyrus. Blood flow in the anterior cingulate gyrus as measured by SPECT may be a simple and good indicator of cerebral functional changes in patients with LC.

Improvement of regional cerebral blood flow after oral intake of branched-chain amino acids in patients with cirrhosis.

AIM: To evaluate the effect of oral intake of branched-chain amino acids (BCAA) on brain perfusion in patients with liver cirrhosis. METHODS: Single photon emission computed tomography scans were performed in 43 patients with cirrhosis and in 15 age-matched healthy subjects. Twenty-nine out of forty-three patients were randomly treated with either BCAA granules or placebo, and single photon emission computed tomography was performed before and after the treatment. We measured the regional cerebral blood flow values using a three-dimensional stereotaxic region of interest template. RESULTS: Cirrhotic patients had regions of significant hypoperfusion in the bilateral central (right P=0.039, P<0.05; left P=0.006 P<0.01), parietal (right P=0.018, P<0.05; left P=0.009, P<0.01), angular (right P=0.039, P<0.05; left P 0.008, P<0.01), and left pericallosal segments (P=0.038 P<0.05) as compared with healthy subjects. A significant increase in cerebral perfusion was observed 70 min after the oral intake of BCAA in the angular (right P=0.012, P<0.05; left P=0.049, P<0.05), temporal (right P=0.012, P<0.05; left P=0.038, P<0.05), pericallosal segments (right P=0.025, P<0.05; left P=0.049, P<0.05) and left precentral (P=0.044, P<0.05), parietal (P=0.040, P<0.05) and thalamus (P=0.033, P<0.05). No significant change in perfusion was observed in the placebo group. CONCLUSION: Administration of BCAA rapidly improves cerebral perfusion.

Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy.

OBJECTIVE: The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed. METHODS: 99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM. RESULTS: On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE. CONCLUSIONS: Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE.

Increased myocardial uptake of iodine-123 metaiodobenzylguanidine on delayed images, compared with early images, in patients with multiple system atrophy.

We present 2 interesting cases of multiple system atrophy in which increased myocardial iodine-123 metaiodobenzylguanidine uptake was observed on delayed images (3 hours after injection) compared with early images (15 minutes after injection). These findings have not been previously described. The duration of symptoms was less than 1 year in both these patients. The mechanism responsible for these findings is not clearly understood, but could be related to the pathophysiological changes in the early stage of multiple systemic atrophy.

Lymphatic mapping and sentinel node biopsy during laparoscopic gastrectomy for early cancer.

BACKGROUND/AIMS: Intraoperative lymphatic mapping and sentinel node (SN) biopsy can potentially be combined with minimally invasive surgery, but there are few reports of laparoscopic lymphatic mapping for gastrointestinal cancer. We examined the feasibility and accuracy of laparoscopic lymphatic mapping in predicting lymph node status in patients with gastric cancer. METHODS: Seventeen patients with gastric cancer invading the mucosal or submucosal layers (T1) underwent laparoscopic gastrectomy with lymphatic mapping between March 2001 and May 2002. The day before surgery, a technetium-99m-labelled tin colloid solution was injected endoscopically around the tumor. Immediately after the pneumoperitoneum, patent blue was injected. Gastrectomy was performed in all patients, and blue-stained or radioactive nodes were defined as SNs. Fresh SNs were immediately processed for frozen-section examination by hematoxylin-eosin (H and E) and immunohistochemical (IHC) staining. All non-SNs harvested from resected specimens were subjected to histological examination with H and E. RESULTS: SNs were detected in all patients by combination of the two kinds of tracers. Three patients had lymph node metastases in their final examination, and SNs in these 3 were operatively diagnosed as positive by H and E or IHC staining. Lymphatic mapping and SN biopsy under laparoscopic surgery were performed with 100% accuracy. CONCLUSION: Our preliminary study shows the feasibility of intraoperative lymphatic mapping in laparoscopic gastrectomy for T1 gastric cancer.

Improvement of regional cerebral blood flow after treatment with branched-chain amino acid solutions in patients with cirrhosis.

OBJECTIVE: The administration of solutions rich in branched-chain amino acids leads to mental recovery from acute hepatic encephalopathy in patients with liver cirrhosis. However, the mechanism of action of branched-chain amino acids remains unclear. The purpose of this study was to evaluate the effect of intravenous infusion of branched-chain amino acids on brain perfusion in patients with liver cirrhosis. METHODS: Single photon emission computed tomography scans were performed in 14 patients with liver cirrhosis before and after the administration of branched-chain amino acids in a single-day split-dose protocol. The per cent change in regional brain perfusion was calculated in high frontal, parietal, temporal, occipital lobes and cerebellum. Thereafter, statistical parametric mapping was performed to identify brain regions with abnormal cerebral perfusion. RESULTS: Intravenous infusion of solutions enriched with branched-chain amino acids induced a 13-20% increase in regional cerebral blood flow. Cirrhotic patients had regions of significant hypoperfusion, as determined by statistical parametric mapping, in the left superior parietal and posterior cingulate as compared to the control group. This hypoperfusion of parietal and cingulate regions was not detected after treatment with solutions of branched-chain amino acids. CONCLUSIONS: The results of the present study suggest that administration of solutions enriched with branched-chain amino acids improves cerebral perfusion in patients with cirrhosis.

Preoperative transcatheter arterial infusion chemotherapy for locally advanced breast cancer (stage IIIb) for down-staging and increase of resectability.

OBJECTIVES: To evaluate the clinical usefulness of preoperative transcatheter arterial infusion chemotherapy (TAIC) for locally advanced breast cancer. METHODS: Seven patients with unresectable locally advanced breast cancer (stage IIIb) underwent TAIC percutaneously 1-3 times (mean, 1.7 times) until tumors became resectable. Anticancer drugs were injected into both the internal mammary and the distal subclavian arteries. RESULTS: There was no major complication related to the procedure. The mean tumor size was significantly decreased from 10.0+/-3.9 to 5.1+/-2.5 cm (P=0.0086). Skin and muscle invasions were improved in two patients (28%) and lymph nodes disappeared in one patient (14%). In two patients (28%), down-staging was achieved from stage IIIb to stage IIIa. All tumors turned into resectable, and mastectomy was performed with a mean period of 35 days (range 9-60 days) after TAIC. Marked decrease in tumor size allowed one patient to receive breast-conserving surgery. There was no local recurrence in any patient. However, five patients (71%) experienced distant metastases. The 3-year disease free and overall survival were 0 and 71.4%, respectively. CONCLUSIONS: TAIC for locally advanced breast cancer is useful in reducing tumor size and achieving down-staging in a relatively short period, leading to an expanded surgical indication.

Arterial chemoinfusion therapy through an implanted port system for patients with unresectable intrahepatic cholangiocarcinoma--initial experience.

Arterial chemoinfusion therapy through an implanted port system was performed for patients with unresectable intrahepatic cholangiocarcinoma (ICC). Eleven patients with unresectable ICC were studied. Seven patients had stage-IV disease, two had stage-III disease, and two had stage-II disease. The mean tumor size was 7.0+/-2.6 cm (range 3.8-13.5 cm). A catheter and port system was percutaneously implanted, and anticancer drugs featuring fluorouracil were administered via the infusion system every 1-2 weeks on the outpatient basis in all patients except 2. Arterial chemoinfusion therapy was repeated 12-84 times per patient (mean 51 times). Partial and minor responses were achieved in sevenents (64%). Disease was stable in two patients (18%), and progressed in the other two patients (18%). Tumor growth was controlled during a mean period of 14.5 months in seven responders and two patients with stable disease. The survival rates were 91% at 1 year, 51% at 2 years, 20% at 3 years, and 10% at 4 years, respectively. The mean survival period was 26 months. Toxicity such as cholangitis and pancytopenia was found in three patients (27%). This treatment seems to improve the prognosis of patients with unresectable ICC and deserves further studies.