18F-FDG uptake in the stomach on screening PET/CT: value for predicting Helicobacter pylori infection and chronic atrophic gastritis.

BACKGROUND: The aim of this study was to determine the value of 18F-FDG uptake on screening PET/CT images for the prediction of Helicobacter pylori (H. pylori) infection and chronic atrophic gastritis. METHODS: Among subjects who underwent 18F-FDG PET/CT for cancer screening from April 2005 to November 2015, PET/CT images were analyzed in 88 subjects who had gastrointestinal fiberscopy within 6 months. The volumes of interest (VOIs) were placed in the fornix, corpus and antrum of the stomach to determine maximal standardized uptake value (SUVmax) and mean SUV (SUVmean). Receiver operating characteristic curve (ROC) analysis was performed to determine the diagnostic performance of SUV indicators in predicting H. pylori infection and chronic atrophic gastritis. RESULTS: SUV indicators of the stomach were significantly higher in subjects with H. pylori infection than those without (from P < 0.001 to P < 0.05). ROC analysis revealed that SUVmean had the highest performance in predicting H. pylori infection (AUC 0.807) and chronic atrophic gastritis (AUC 0.784). SUVmean exhibited the sensitivity of 86.5 % and the specificity of 70.6 % in predicting H. pylori infection, and the sensitivity of 75.0 % and 78.6 % in predicting chronic atrophic gastritis. CONCLUSION: Assessment of 18F-FDG uptake in the stomach reflecting active inflammation is useful in predicting patients with H. pylori infection and subsequent chronic atrophic gastritis which is closely associated with the risk of gastric neoplasms.

Respiratory-gated time-of-flight PET/CT during whole-body scan for lung lesions: feasibility in a routine clinical setting and quantitative analysis.

PURPOSE: To demonstrate the feasibility of respiratory gating during whole-body scan for lung lesions in routine 18F-FDG PET/CT examinations using a time-of-flight (TOF)-capable scanner to determine the effect of respiratory gating on reduction of both misregistration (between CT and PET) and image blurring, and on improvement of the maximum standardized uptake value (SUVmax). MATERIALS AND METHODS: Patients with lung lesions who received FDG PET/CT were prospectively studied. Misregistration, volume of PET (Vp), and SUVmax were compared between ungated and gated images. The difference in respiratory gating effects was compared between lesions located in the upper or middle lobes (UML) and the lower lobe (LL). The correlation between three parameters (% change in misregistration, % change in Vp, and lesion size) and % change in SUVmax was analyzed. RESULTS: The study population consisted of 60 patients (37 males, 23 females; age 68 ± 12 years) with lung lesions (2.5 ± 1.7 cm). Fifty-eight out of sixty respiratory gating studies were successfully completed with a total scan time of 20.9 ± 1.9 min. Eight patients' data were not suitable for analysis, while the remaining 50 patients' data were analyzed. Respiratory gating reduced both misregistration by 21.4 % (p < 0.001) and Vp by 14.2 % (p < 0.001). The SUVmax of gated images improved by 14.8 % (p < 0.001). The % change in misregistration, Vp, and SUVmax by respiratory gating tended to be larger in LL lesions than in UML lesions. The correlation with % change in SUVmax was stronger in % change in Vp (r = 0.57) than % change in misregistration (r = 0.35). There was no statistically significant correlation between lesion size and % change in SUVmax (r = -0.20). CONCLUSIONS: Respiratory gating during whole-body scan in routine TOF PET/CT examinations is feasible and can reduce both misregistration and PET image blurring, and improve the SUVmax of lung lesions located primarily in the LL.

The Effect of Misregistration Between CT-Attenuation and PET-Emission Images in 13N-Ammonia Myocardial PET/CT.

UNLABELLED: In 2-dimensional cardiac PET/CT, misregistration between the PET and CT images due to respiratory and cardiac motion causes tracer uptake to appear substantially reduced. The resolution and quality of the images have been considerably improved by the use of 3-dimensional (3D) PET acquisitions. In the current study, we investigated the impact that misregistration between PET and CT images has on myocardial (13)N-ammonia uptake in images reconstructed with 3D ordered-subset expectation maximization combined with time-of-flight and point-spread-function modeling. METHODS: Eight healthy volunteers (7 men and 1 woman; mean age ± SD, 53 ± 19 y) underwent (13)N-ammonia cardiac PET/CT at rest. First, any misregistration between the PET and CT images was manually corrected to generate reference images. Then, the images were intentionally misregistered by shifting the PET images from the reference images by a degree of 1, 2, 3, 4, 5, 10, and 15 mm along both the x-axis (left) and the z-axis (cranial). For each degree of misregistration, the PET images were reconstructed using the CT-attenuation images. The left ventricular short-axis PET/CT images were divided into 4 segments: anterior wall, inferior wall, lateral wall, and septum. The erroneous decrease in myocardial uptake in basal, mid, and apical slices was visually graded using a 4-point scale (0 = none, 1 = mild, 2 = moderate, and 3 = severe). Wall-to-septum uptake ratios were evaluated for the anterior, inferior, and lateral walls in the basal, mid, and apical slices. RESULTS: A statistically significant reduction in myocardial (13)N-ammonia uptake in the anterior (P < 0.01) and lateral (P < 0.05) walls was observed when misregistration was 10 mm or more. The uptake ratios for the anterior, lateral, and inferior walls in the reference images were 1.00 ± 0.04, 0.96 ± 0.08, and 0.91 ± 0.03, respectively. The ratios for the anterior and lateral walls significantly decreased when misregistration exceeded 10 mm (anterior wall, 0.80 ± 0.06, P < 0.0001; lateral wall, 0.82 ± 0.07, P < 0.01), whereas the ratio for the inferior wall was relatively small at all 7 degrees of misregistration (0.86 ± 0.05 at 15-mm misregistration, P = 0.06). CONCLUSION: In PET/CT images reconstructed with 3D ordered-subset expectation maximization combined with time-of-flight and point-spread-function modeling, we found a statistically significant artifactual reduction in tracer uptake in heart regions overlapping lung when misregistration between PET and CT exceeded 10 mm.

Impact of 18F-FDG-PET/CT on treatment strategy in colorectal cancer lung metastasis before lung radiofrequency ablation.

OBJECTIVE: The aim of the study was to evaluate prospectively the clinical impact of 2-(F)-fluoro-2-deoxy-D-glucose (F-FDG) PET/computed tomography (CT) on the pretreatment assessment of patients with colorectal lung metastasis before radiofrequency (RF) ablation. METHODS: The institutional review board approved this prospective study. The eligibility criteria for lung RF ablation were the presence of five or fewer colorectal lung metastases with a maximum tumor size of 3 cm and absence of extrapulmonary lesions. Lung RF ablation candidates who underwent pretreatment PET/CT studies were included. The incidence of detection of unexpected recurrent lesions on PET/CT was evaluated, along with its impact on subsequent treatments. Factors linked with the incidence of unexpected recurrent lesions were evaluated using univariate and multivariate analyses. RESULTS: Between October 2008 and June 2011, 60 patients were enrolled. Among the unexpected abnormal F-FDG accumulations found in 13 patients (21.7%), presence of extrapulmonary lesions was proved in 12 patients (20.0%, 12/60), prompting treatment strategy changes. One false-positive case was found (1.7%, 1/60). The sensitivity, specificity, and accuracy in detecting unexpected lesions by PET/CT were, respectively, 100, 97.9, and 98.3%. Elevation of the serum carcinoembryonic antigen level (>6.0 ng/ml) was the only significant factor linked with unexpected lesions in both univariate (P=0.02) and multivariate analyses (P=0.02). CONCLUSION: A PET/CT study should be performed in patients with colorectal lung metastasis before selecting them for lung RF ablation, especially when the carcinoembryonic antigen level is elevated.

Detection of local tumor progression by (18)F-FDG PET/CT following lung radiofrequency ablation: PET versus CT.

OBJECTIVE: The objective of this study was to compare the diagnostic performance for detecting local tumor progression between FDG PET and CT in patients who received lung radiofrequency (RF) ablation for the treatment of malignant lung tumors. METHODS: A total of 469 FDG PET/CT studies were performed at 4 time points (3, 6, 9, 12 months) after lung RF ablation in 143 patients (87 male and 56 female patients) with 231 tumors. The SUVmax was calculated in treated tumors in each PET image. The percentage decrease (% decrease) in ablative zone size was evaluated in each CT image. The final response was judged based on follow-up findings and histology. Diagnostic performance of FDG PET and CT images was evaluated using receiver operating characteristic analysis. RESULTS: Local tumor progression was identified in 37 patients (25.9%, 37/143) having 47 tumors (20.4%, 47/231) during the median follow-up of 24 months (range, 8-75 months). The area under the receiver operating characteristic curve of PET was higher than that of CT at all 4 time points (0.71 vs 0.55 at 3 months, 0.82 vs 0.60 at 6 months, 0.84 vs 0.66 at 9 months, and 0.92 vs 0.68 at 12 months), and its diagnostic performance was significant at each time point (P = 0.0010 at 3 months and P < 0.001 at 6, 9, and 12 months). However, the area under the receiver operating characteristic curve of CT was significant at 9 months (P = 0.040) and 12 months (P = 0.032). CONCLUSIONS: FDG PET/CT is better able to assess local tumor progression at 3 and 6 months after lung RF ablation than CT alone.

Relation between FDG uptake and apparent diffusion coefficients in glioma and malignant lymphoma.

OBJECTIVE: This study evaluates the relation between 2-deoxy-2-[18F]fluoro-D: -glucose (FDG) uptake using positron emission tomography/CT and the apparent diffusion coefficient (ADC) in patients with glioma and malignant lymphoma. METHODS: For 36 patients (30 with glioma and 6 with malignant lymphoma), the standardized uptake value (SUV) ratio was calculated to assess the FDG uptake. Pearson's correlation analysis was used to assess the relation between the SUV ratio and the ADC value: those of low-grade glioma and high-grade glioma were compared, as were those of glioblastoma and malignant lymphoma. RESULTS: Inverse correlation between the SUV ratio and the minimum ADC was found for all cases (P < 0.0001, r = 0.68) and for glioma cases (P < 0.0001, r = 0.67). High-grade gliomas showed a significantly higher SUV ratio than low-grade gliomas did (P < 0.0001); they also showed significantly lower minimum ADC than low-grade gliomas did (P < 0.001). Cut-off values used for the SUV ratio of 0.9 and for the minimum ADC of 0.99 × 10(-3 )mm(2)/s were used to differentiate high-grade from low-grade gliomas, with high accuracy. Malignant lymphoma showed a significantly higher SUV ratio than glioblastoma (P < 0.0001). No significant difference in the ADC value was found between glioblastoma and malignant lymphoma (the minimum ADC: P = 0.13, the mean ADC: P = 0.084, respectively). CONCLUSIONS: An inverse correlation was found between the SUV ratio and the minimum ADC in glioma and malignant lymphoma. The SUV ratio and the minimum ADC are useful to evaluate the grading of gliomas. The SUV ratio might be more useful for differentiating malignant lymphoma from glioblastoma than the ADC value is.

Assessment of factors influencing FDG uptake in non-small cell lung cancer on PET/CT by investigating histological differences in expression of glucose transporters 1 and 3 and tumour size.

PURPOSE: The objective of this study was to evaluate the major factors influencing on FDG uptake in non-small cell lung cancer (NSCLC) by investigating histological difference in the expression of glucose transporters 1 and 3 (Glut-1 and Glut-3) and tumour size. METHODS: This study enrolled 32 patients including 9 with squamous cell carcinoma (SCC) and 23 with adenocarcinoma (AC). The AC cases comprised 16 AC with mixed subtypes (AC-mixed) and 7 localized AC in situ (localized bronchioloalveolar carcinoma). Partial volume effect corrected maximum standardized uptake values (cSUVmax) and tumour size were obtained using FDG PET/CT. Glut-1 and Glut-3 expression were evaluated using five-point grading scales. RESULTS: Overexpression of Gluts was observed at high rates (88% for Glut-1 and 97% for Glut-3). They were mutually correlated. cSUVmax showed better correlation with size than with Gluts overexpression. AC and SCC showed a high positive expression rate for both Glut-1 and Glut-3, although the degree of overexpression was significantly higher in SCC than AC. In addition, localized AC in situ revealed a considerably higher positive expression rate and similar degrees of overexpression for both Glut-1 and Glut-3 compared with AC-mixed. By contrast, localized AC in situ alone was significantly smaller in both cSUVmax and size than either SCC or AC-mixed. No significant difference was found in cSUVmax or size between SCC and AC-mixed. CONCLUSIONS: The FDG uptake of NSCLC might be dependent on size rather than on overexpression of Glut-1 or Glut-3. Low FDG uptake in localized AC in situ might result from its small size rather than Glut overexpression.

Complete regression of multiple painful bone metastases from hepatocellular carcinoma after administration of strontium-89 chloride.

A 69-year-old man received strontium-89 chloride intravenous injection to relieve uncontrollable pain from multiple hepatocellular carcinoma bone metastases. Pain was resolved 3 months later without opioid analgesics. Multiple bone metastases showed complete regression 4 months later. The patient lived for 1 year without recurrence of bone metastasis.

Three-dimensional stereotactic ROI template for measuring regional cerebral blood flow in 99mTc-ECD SPECT: comparison with the manual tracing method.

PURPOSE: The three-dimensional stereotactic region of interest template (3DSRT) is computer software, which enables the automatic measurement of regional cerebral blood flow (rCBF). This study was undertaken to compare the rCBF values obtained using the 3DSRT method and the conventional manual tracing method. MATERIALS AND METHODS: Twelve patients with normal brains who underwent technetium-99m L,L-ethyl cysteinate dimer single-photon emission computed tomography studies were enrolled in this study. The brains were divided into 12 segments in each hemisphere, and rCBF was measured in each segment. The regions of interest were automatically placed in the segments in the 3DSRT method and were manually traced by five nuclear medicine technicians in the manual tracing method. The rCBF values obtained were compared between the two methods. Interoperator reliability was evaluated in the manual tracing method. RESULTS: The rCBF values were significantly higher in the manual tracing method than in the 3DSRT method in all segments except for the angular segment. A good correlation was seen between the two methods in the rCBF values in 10 (83.3%) of the 12 brain segments (range of coefficient of determinations: 0.73-0.94). A poor correlation, however, was seen in the pericallosal (0.50) and hippocampal (0.53) segments. Interoperator reliability was lower in these two segments than in the other segments in the manual tracing method. CONCLUSION: Although the rCBF values obtained using the manual tracing method and the 3DSRT method show good correlation in most segments, care is required when comparing the results for the pericallosal and hippocampal segments.

Assessment of coronary arteries with total study time of less than 30 minutes by using whole-heart coronary MR angiography.

This study had institutional review board approval, and all patients gave informed consent. The purpose of this study was to prospectively evaluate the use of whole-heart three-dimensional (3D) coronary magnetic resonance (MR) angiography in patients suspected of having coronary artery disease. Whole-heart coronary MR angiography was performed in 39 patients (30 men and nine women; mean age, 63.9 years +/- 15.6 [standard deviation]) by using a steady-state free precession sequence with free breathing. Twenty patients (16 men and four women; mean age, 64.9 years +/- 11.7) also underwent conventional coronary angiography. MR angiography was successfully completed in 34 of 39 patients (87%); the average imaging time was 13.8 minutes +/- 3.8. Sensitivity and specificity of MR angiography for detecting significant stenosis were 82% (14 of 17 arteries) and 91% (39 of 43 arteries), respectively. Whole-heart coronary MR angiography with a navigator-gated steady-state sequence can enable reliable 3D visualization of the coronary arteries in patients suspected of having coronary artery disease.

Diagnostic accuracy of stress first-pass contrast-enhanced myocardial perfusion MRI compared with stress myocardial perfusion scintigraphy.

OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery prepared turbo fast low-angle shot (turbo FLASH) compared with stress myocardial perfusion scintigraphy. Recent studies show that first-pass contrast-enhanced myocardial perfusion MRI can provide noninvasive detection of low-limiting stenosis in the coronary artery. MATERIALS AND METHODS: First-pass contrast-enhanced MR images were acquired at rest and during stress in 40 patients with suspected coronary artery disease. All patients underwent thallium-201 SPECT without attenuation correction and coronary angiography. Two reviewers independently assigned one of five confidence grades without knowing the results of coronary angiography for receiver operating characteristic (ROC) analysis. Luminal stenosis >70% on coronary angiography was used as a reference standard. RESULTS: On coronary angiography, 70% or greater diameter stenosis of the coronary artery was observed in 21 (52.5%) of 40 patients. The areas under the ROC curve for detection of significant stenosis in the individual coronary artery were 0.86 (observer 1) and 0.84 (observer 2) for MRI. These values were 0.79 (observer 1, p = not significant) and 0.72 (observer 2, p = not significant) for 201Tl SPECT. CONCLUSION: The diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery-prepared turbo FLASH was comparable with that of stress 201Tl SPECT. Stress first-pass contrast-enhanced MRI is a noninvasive technique that can be used as an alternative to stress myocardial perfusion scintigraphy.

Late gadolinium-enhanced magnetic resonance imaging in acute and chronic myocardial infarction. Improved prediction of regional myocardial contraction in the chronic state by measuring thickness of nonenhanced myocardium.

OBJECTIVES: We sought to determine serial changes of enhanced and nonenhanced tissue on late gadolinium-enhanced cardiac magnetic resonance (CMR) imaging in patients with a myocardial infarction (MI) and to assess whether thickness of nonenhanced myocardium can improve the detection of preserved contractile function in the chronic state. BACKGROUND: Previous studies demonstrated that enhancement on late gadolinium-enhanced CMR images indicates myocardial necrosis, and nonenhancement shows the presence of viable myocardium. METHODS: The CMR studies were performed within one week (scan 1) and more than five months (scan 2) after the onset of MI in 18 patients. The area and mean thickness of enhanced tissue and nonenhanced myocardium were measured by using a 30-segment model. Systolic wall thickening on cine CMR at scan 2 was assessed for evaluating regional contractile function. RESULTS: The amount of enhanced tissue significantly decreased from scan 1 to 2 (22.1 +/- 14.0 ml vs. 15.0 +/- 9.3 ml, p < 0.001). The averaged thickness of nonenhanced myocardium in the infarct segments significantly increased from scan 1 to 2 (5.2 +/- 3.0 mm vs. 6.6 +/- 3.2 mm, p < 0.001). Receiver operating characteristic analysis demonstrated that the measurement of thickness of nonenhanced myocardium, compared with measurement of percent transmural enhancement, had better diagnostic accuracy for predicting improved systolic wall thickening form scan 1 to 2 in dysfunctional segments (Az 0.650 vs. 0.594, p < 0.05). CONCLUSIONS: The amounts of enhanced tissue and nonenhanced myocardium significantly altered from the acute to chronic state in MI patients. The diagnostic performance of CMR imaging for detection of preserved contractile function can be significantly improved by measuring thickness of nonenhanced myocardium in MI patients.