Clinical impact of gastrointestinal endoscopy on the early detection of pharyngeal squamous cell carcinoma: A retrospective cohort study.

BACKGROUND: In recent years, with the growing availability of image-enhanced gastrointestinal endoscopy, gastroenterologists have contributed to the early detection of pharyngeal squamous cell carcinomas (SCC). AIM: To clarify the clinical characteristics of pharyngeal SCCs detected by gastrointestinal endoscopy. METHODS: This is a retrospective cohort study conducted in a single-center, a university hospital in Japan. We retrospectively assessed the clinical records of 522 consecutive patients with oropharyngeal or hypopharyngeal SCC who were examined in our hospital between 2011 and 2018. The lesions were classified into two groups: Group GE (detected by gastrointestinal endoscopy) and Group non-GE (detected by means other than gastrointestinal endoscopy). The clinical characteristics were compared between the two groups. Continuous data were compared using the Mann-Whitney U test. Pearson's χ 2 test or Fisher's exact test was used to analyze the categorical data and compare proportions. The Kaplan-Meier method was used to estimate the cumulative patient survival rates. RESULTS: In our study group, the median age was 65 years and 474 patients (90.8%) were male. One hundred and ninety-six cases (37.5%) involved the oropharynx and 326 cases (62.5%) involved the hypopharynx. Three hundred and ninety-five cases (75.7%) had some symptoms at the time of diagnosis. One hundred and forty-five (27.8%) cases had concurrent ESCC or a history of ESCC. One hundred and sixty-four (31.4%) cases were detected by gastrointestinal endoscopy and classified as Group GE. The proportions of asymptomatic cases, cTis-1 cases and cases with no lymph node metastasis were significantly higher in Group GE than Group non-GE (61.6% vs 7.3%, P < 0.001, 32.9% vs 12.0%, P < 0.001 and 69.5% vs 19.0%, P < 0.001). Endoscopic laryngo-pharyngeal surgery or endoscopic submucosal dissection were performed in only 0.6% of the lesions in Group non-GE but in 21.3% of the lesions in Group GE (P < 0.001). Overall survival was significantly longer in Group GE than in Group non-GE (P = 0.018). The 2-year and 4-year survival rates were 82.5% and 70.7% in Group GE, and 71.5% and 59.0% in Group non-GE, respectively. CONCLUSION: Gastrointestinal endoscopy plays an important role in the early detection and improving the prognosis of pharyngeal SCCs.

CT texture analysis for the prediction of KRAS mutation status in colorectal cancer via a machine learning approach.

PURPOSE: This study aimed to investigate whether a machine learning-based computed tomography (CT) texture analysis could predict the mutation status of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) in colorectal cancer. METHOD: This retrospective study comprised 40 patients with pathologically confirmed colorectal cancer who underwent KRAS mutation testing, contrast-enhancement CT, and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) before treatment. Of the 40 patients, 20 had mutated KRAS genes, whereas 20 had wild-type KRAS genes. Fourteen CT texture parameters were extracted from portal venous phase CT images of primary tumors, and the maximum standard uptake values (SUVmax) on 18F-FDG PET images were recorded. Univariate logistic regression was used to develop predictive models for each CT texture parameter and SUVmax, and a machine learning method (multivariate support vector machine) was used to develop a comprehensive set of CT texture parameters. The area under the receiver operating characteristic (ROC) curve (AUC) of each model was calculated using five-fold cross validation. In addition, the performance of the machine learning method with the CT texture parameters was compared with that of SUVmax. RESULTS: In the univariate analyses, the AUC of each CT texture parameter ranged from 0.4 to 0.7, while the AUC of the SUVmax was 0.58. Comparatively, the multivariate support vector machine with comprehensive CT texture parameters yielded an AUC of 0.82, indicating a superior prediction performance when compared to the SUVmax. CONCLUSIONS: A machine learning-based CT texture analysis was superior to the SUVmax for predicting the KRAS mutation status of a colorectal cancer.

Impact of hybrid FDG-PET/CT on gross tumor volume definition of cervical esophageal cancer: reducing interobserver variation.

Intensity-modulated radiation therapy is being increasingly used to treat cervical esophageal cancer (CEC); however, delineating the gross tumor volume (GTV) accurately is essential for its successful treatment. The use of computed tomography (CT) images to determine the GTV produces a large degree of interobserver variation. In this study, we evaluated whether the use of [18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET)/CT fused images reduced interobserver variation, compared with CT images alone, to determine the GTV in patients with CEC. FDG-PET/CT scans were obtained for 10 patients with CEC, imaged positioned on a flat tabletop with a pillow. Five radiation oncologists independently defined the GTV for the primary tumors using routine clinical data; they contoured the GTV based on CT images (GTVCT), followed by contouring based on FDG-PET/CT fused images (GTVPET/CT). To determine the geometric observer variation, we calculated the conformality index (CI) from the ratio of the intersection of the GTVs to their union. The interobserver CI was compared using Wilcoxon's signed rank test. The mean (±SD) interobserver CIs of GTVCT and GTVPET/CT were 0.39 ± 0.15 and 0.58 ± 0.10, respectively (P = 0.005). Our results suggested that FDG-PET/CT images reduced interobserver variation when determining the GTV in patients with CEC. FDG-PET/CT may increase the consistency of the radiographically determined GTV in patients with CEC.

Dual-energy computed tomography colonography using dual-layer spectral detector computed tomography: Utility of virtual monochromatic imaging for electronic cleansing.

OBJECTIVE: To assess the utility of virtual monochromatic imaging (VMI) using a dual-layer spectral detector CT for electronic cleansing in fecal-tagging CT colonography (CTC). METHODS: This study included 35 patients who underwent fecal-tagging CTC with a dual-layer detector spectral CT scanner. Conventional images at 120 kVp and VMI at 40, 50, and 60 keV were reconstructed. Quantitative image quality parameters, i.e., tagging density and image noise, were compared and the visual image quality was scored on a four-point scale. We recorded the number of the colon segments with appropriate tagging density (≥300 HU) for each patient and used these data to compare the reconstructions. In addition, electronic cleansing performance was semi-quantitatively assessed using a four-point scale. RESULTS: The mean tagging density on VMI was significantly higher than that on conventional 120 kVp images. The number of colon segments with appropriate tagging density on VMI were significantly higher than that on conventional 120 kVp images. There was no significant difference among the reconstructed images with respect to image noise. Scores for subjective image quality and electronic cleansing performance on VMI were significantly higher than those on conventional 120 kVp images. CONCLUSION: With dual-layer spectral detector CT, VMI can yield significantly better fecal-tagged CTC image quality and improve electronic cleansing performance.

Advanced parametric imaging for evaluation of Crohn's disease using dual-energy computed tomography enterography.

We describe a case of small bowel Crohn's disease in which dual-energy computed tomography enterography using dual-layer spectral detector scanner contributed to quantitative assessment, and provided a higher degree of confidence pertaining to the diagnosis. Dual-layer spectral detector computed tomography enables retrospective analysis including virtual monochromatic imaging, iodine mapping, and determining the effective atomic number Z with routine scan protocols. These advanced parametric dual-energy imaging holds promising potential as an imaging biomarker for diagnosis, risk-stratification, monitoring of disease progression and therapy, and outcome prediction.

Contrast enhancement in abdominal computed tomography: influence of photon energy of different scanners.

OBJECTIVE: Different CT scanners have different X-ray spectra and photon energies indicating that contrast enhancement vary among scanners. However, this issue has not been fully validated; therefore, we performed phantom and clinical studies to assess this difference. METHODS: Two scanners were used: scanner-A and scanner-B. In the phantom study, we compared the contrast enhancement between the scanners at tube voltage peaks of 80, 100 and 120 kVp. Then, we calculated the effective energies of the two CT scanners. In the clinical study, 40 patients underwent abdominal scanning with scanner-A and another 40 patients with scanner-B, with each group using the same scanning protocol. The contrast enhancement of abdominal organs was assessed quantitatively (based on the absolute difference between the attenuation of unenhanced scans and contrast-enhanced scans) and qualitatively. A two-tailed independent Student's t-test and or the Mann-Whitney U test were used to compare the discrepancies. RESULTS: In the phantom study, contrast enhancement for scanner-B was 36.9, 32.6 and 30.8% higher than that for scanner-A at 80, 100 and 120 kVp, respectively. The effective energies were higher for scanner-A than for scanner-B. In the quantitative analysis for the clinical study, scanner-B yielded significantly better contrast enhancement of the hepatic parenchyma, pancreas, kidney, portal vein and inferior vena cava compared with that of scanner-A. The mean visual scores for contrast enhancement were also significantly higher on images obtained by scanner-B than those by scanner-A. CONCLUSION: There were significant differences in contrast enhancement of the abdominal organs between the compared CT scanners from two different vendors even at the same scanning and contrast parameters. Advances in knowledge: Awareness of the impact of different X-ray energies on the resultant attenuation of contrast material is important when interpreting clinical CT images.

Model-based Iterative Reconstruction in Low-radiation-dose Computed Tomography Colonography: Preoperative Assessment in Patients with Colorectal Cancer.

RATIONALE AND OBJECTIVES: To assess the effect of model-based iterative reconstruction (MBIR) on image quality and diagnostic performance of low-radiation-dose computed tomography colonography (CTC) in the preoperative assessment of colorectal cancer. MATERIALS AND METHODS: This study included 30 patients with colorectal cancer referred for surgical treatment. All patients underwent CTC with a standard dose (SD) protocol in the supine position and a low-dose (LD; radiation dose reduction of approximately 85%) protocol in the prone position. The SD protocol images were post-processed using filtered back projection (FBP), whereas the LD protocol images were post-processed using FBP and MBIR. Objective and subjective image quality parameters were compared among the three different methods. Preoperative evaluations, including site, length, and tumor and node staging were performed, and the findings were compared to the postsurgical findings. RESULTS: The mean image noise of SD-FBP, LD-FBP, and LD-MBIR images was 17.3 ± 3.2, 40.5 ± 10.9, and 11.2 ± 2.0 Hounsfield units, respectively. There were significant differences for all comparison combinations among the three methods (P < .01). For image noise, the mean visual scores were significantly higher for SD-FBP and LD-MBIR than for LD-FBP, and the scores for SD-FBP and LD-MBIR were equivalent (3.9 ± 0.3 [SD-FBP], 2.0 ± 0.5 [LD-FBP], and 3.7 ± 0.3 [LD-MBIR]). Preoperative information was more accurate under SD-FBP and LD-MBIR than under LD-FBP, and the information was comparable between SD-FBP and LD-MBIR. CONCLUSION: MBIR can yield significantly improved image quality on low-radiation-dose CTC and provide preoperative information equivalent to that of standard-radiation-dose protocol.

Clinical potential of retrospective on-demand spectral analysis using dual-layer spectral detector-computed tomography in ischemia complicating small-bowel obstruction.

We describe a case of ischemia complicating acute small-bowel obstruction in which retrospective on-demand spectral analysis using dual-layer spectral detector computed tomography (CT) provided a higher degree of confidence pertaining to the diagnosis. Dual-layer spectral detector CT enables retrospective on-demand spectral analysis, including virtual monochromatic imaging, iodine mapping, and determining the effective atomic number Z, without the need of a pre-scan setting requiring a special protocol, particularly facilitating emergency situations. Retrospective on-demand spectral analysis could improve the accuracy and diagnostic confidence in cases with ischemia complicating small-bowel obstruction.

Using 80 kVp on a 320-row scanner for hepatic multiphasic CT reduces the contrast dose by 50 % in patients at risk for contrast-induced nephropathy.

OBJECTIVES: We evaluated the effects of a low contrast material (CM) dose protocol using 80-kVp on the image quality of hepatic multiphasic CT scans acquired on a 320-row CT scanner. METHODS: We scanned 30 patients with renal insufficiency (eGFR < 45 mL/min/1.73 m2) using 80-kVp and a CM dose of 300mgI/kg. Another 30 patients without renal insufficiency (eGFR > 60 mL/min/1.73 m2) were scanned with the conventional 120-kVp protocol and the standard CM dose of 600mgI/kg. Quantitative image quality parameters, i.e. CT attenuation, image noise, and the contrast-to-noise ratio (CNR) were compared and the visual image quality was scored on a four-point scale. The volume CT dose index (CTDIvol) and the size-specific dose estimate (SSDE) recorded with the 80- and the 120-kVp protocols were also compared. RESULTS: Image noise and contrast enhancement were equivalent for the two protocols. There was no significant difference in the CNR of all anatomic sites and in the visual scores for overall image quality. The CTDIvol and SSDE were approximately 25-30 % lower under the 80-kVp protocol. CONCLUSION: Hepatic multiphase CT using 80-kVp on a 320-row CT scanner allowed for a decrease in the CM dose and a reduction in the radiation dose without image quality degradation in patients with renal insufficiency. KEY POINTS: • The 80-kVp CT protocol enabled reduction of contrast dose by 50 % • The 80-kVp CT protocol reduced the radiation dose by 25-33 % • There was no degradation in the image quality of the 80-kVp protocol.

Incidence and risk factors of synchronous colorectal cancer in patients with esophageal cancer: an analysis of 480 consecutive colonoscopies before surgery.

BACKGROUND: The precise incidence rates of multiple primary colorectal cancers in esophageal cancer patients are unknown. METHODS: In total, 480 consecutive patients with esophageal cancers surgically resected in the Kumamoto University Hospital received preoperative total colonoscopy for the assessment of colorectal disease between April 2005 and February 2016. We retrospectively investigated the occurrence of synchronous colorectal cancer with esophageal cancer. In addition, we examined the risk factors for the incidence of multiple primary colorectal cancers. RESULTS: Of the 480 patients, 14 (2.9 %) had synchronous colorectal cancers, 13 had well-differentiated tubular adenocarcinomas, and 1 had papillary adenocarcinoma. Other 14 patients had metachronous colorectal cancer. The current incidence rates of synchronous and total (both synchronous and metachronous) colorectal cancers outnumbered those in normal healthy population and those in esophageal cancer patients which previously reported by The Japan Esophageal Society. The age ≥70 years (hazard ratio 4.82, 95 % confidence interval 1.473-15.78; p = 0.009) and Brinkman index ≥800 (hazard ratio 3.47, 95 % confidence interval 1.056-11.37; p = 0.040) were the independent risk factors for the incidence of synchronous colorectal cancer. They were also the independent risk factors for the incidence of total colorectal cancer. CONCLUSIONS: The results of the present study suggested that pretreatment screening with total colonoscopy is meaningful for patients with esophageal cancer, because the frequency of synchronous colorectal cancer was not negligible. Particularly, in patients >70 years and with history of heavy smoking, pretreatment colonoscopy might be necessary.

Reducing the Radiation Dose for CT Colonography: Effect of Low Tube Voltage and Iterative Reconstruction.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the effect of a low-tube-voltage technique and iterative reconstruction (IR) on the radiation dose and image quality of computed tomography colonography (CTC). MATERIALS AND METHODS: We studied 30 patients (14 women and 16 men; mean age, 64.5 ± 13.1 years; range, 39-90 years) with colorectal cancer referred for surgical treatment. All underwent CTC with fecal tagging under a standard 120-kVp protocol in the supine position and a 100-kVp protocol in the prone position. The 120-kVp images were reconstructed with filtered back projection (FBP). The 100-kVp images were postprocessed using FBP and a hybrid type of IR (adaptive iterative dose reduction 3D). The effective radiation dose (ED), image noise, and contrast-to-noise ratio (CNR) were compared among the three protocols. The visual image quality was scored on a four-point scale. RESULTS: The mean ED was significantly lower under the 100-kVp protocol than the 120-kVp protocol, resulting in a 27% radiation dose decrease (3.5 ± 2.0 vs 2.5 ± 1.5 mSv; P < .01). Image noise decreased by 48%, and the mean attenuation of tagged fluid increased from 452 to 558 HU on images acquired at 100 kVp with IR compared to that in the 120-kVp protocol; these differences were significant. The mean CNR was significantly higher under the 100 kVp with IR than the other two protocols. We found no significant differences in the visual scores for diagnostic utility between the 100 kVp with IR and the 120 kVp with FBP protocol (P = .10). CONCLUSIONS: Low-tube-voltage CTC reduced the radiation dose by approximately 27% while maintaining the image quality.

Dynamic computed tomography of locally advanced pancreatic cancer: effect of low tube voltage and a hybrid iterative reconstruction algorithm on image quality.

OBJECTIVE: The objective of this study was to evaluate the effect of a low-tube-voltage technique and hybrid iterative reconstruction (HIR) on image quality at dynamic computed tomography (CT) of the pancreas. METHODS: The study included 18 consecutive patients (10 women, 8 men; mean age, 68.5 ± 9.5 years) with locally advanced pancreatic cancer who received chemotherapy and had stable disease during the 100- and 120-kV CT studies. The 120-kV images were reconstructed using filtered back projection, and the 100-kV images were postprocessed using filtered back projection and HIR. Scans obtained during 3 pancreatic phases were subjected to quantitative and qualitative analysis. RESULTS: The mean effective dose was significantly lower under the 100- than the 120-kV protocols (29.2 ± 3.6 vs 52.1 ± 5.1 mSv; P < 0.01). The mean contrast-to-noise ratio of the pancreatic cancer and the visual scores were significantly higher under 100 kV with HIR than those under the other 2 protocols (P < 0.01). CONCLUSIONS: Use of low tube voltage and HIR can provide significantly improved image quality at pancreatic dynamic CT.

Human cerebral cortices: signal variation on diffusion-weighted MR imaging.

INTRODUCTION: We have often encountered high signal intensity (SI) of the cingulate gyrus and insula during diffusion-weighted magnetic resonance imaging (DW-MRI) on neurologically healthy adults. To date, cortical signal heterogeneity on DW images has not been investigated systematically. The purpose of our study was to determine whether there is regional signal variation in the brain cortices of neurologically healthy adults on DW-MR images. METHODS: The SI of the cerebral cortices on DW-MR images at 1.5 T was evaluated in 50 neurologically healthy subjects (34 men, 16 women; age range 33-84 years; mean age 57.6 years). The cortical SI in the cingulate gyrus, insula, and temporal, occipital, and parietal lobes was graded relative to the SI of the frontal lobe. Contrast-to-noise ratios (CNRs) on DW-MR images were compared for each cortical area. Diffusion changes were analyzed by visually assessment of the differences in appearance among the cortices on apparent diffusion coefficient (ADC) maps. RESULTS: Increased SI was frequently seen in the cingulate gyrus and insula regardless of patient age. There were no significant gender- or laterality-related differences. The CNR was significantly higher in the cingulate gyrus and insula than in the other cortices (p< .01) , and significant differences existed among the cortical regions (p< .001). There were no apparent ADC differences among the cortices on ADC maps. CONCLUSION: Regional signal variation of the brain cortices was observed on DW-MR images of healthy subjects, and the cingulate gyrus and insula frequently manifested high SI. These findings may help in the recognition of cortical signal abnormalities as visualized on DW-MR images.

Positional lumbar imaging using a positional device in a horizontally open-configuration MR unit - initial experience.

PURPOSE: To evaluate whether positional MR images of the lumbar spine, obtained with a horizontally open-configuration MR unit, demonstrate positional changes of the dural sac, and to assess whether there are significant differences in positional changes between healthy volunteers and patients with chronic low back pain. MATERIALS AND METHODS: The study population consisted of 15 patients with chronic low back pain and 14 healthy volunteers. MR images were obtained using a horizontally open-configuration 0.4-T MR unit. After conventional lumbar MR examinations, images were obtained in the flexion, neutral, and extension positions, using a positioning device. The anteroposterior diameter of the dural sac at the level of each lumbar disk was measured in the three positions and quantitative data were compared. RESULTS: Our MR protocol was tolerated by all patients. In both patients and volunteers, the mean anteroposterior diameter of the dural sac was smaller in the extension positions than in the flexion positions. In the mean rate of change (RC) in the dural sac diameter at the site of the degenerated disks, the difference between the volunteers and patients was significant (P < 0.05). There was no significant difference in the mean RC between patients and volunteers without degenerative disks. CONCLUSION: Using a horizontally open-configuration MR unit, positional MR imaging provided position-dependent change of the dural sac. Positional changes at the site of the degenerated disks may be different in patients with and without chronic low back pain.

Multidetector CT findings suggesting a perforation site in the gastrointestinal tract: analysis in surgically confirmed 155 patients.

PURPOSE: The aim of this study was to investigate how accurately we could diagnose the level of gastrointestinal (GI) tract perforation using multidetector computed tomography (MDCT). MATERIALS AND METHODS: We reviewed 155 patients with surgically confirmed GI tract perforation. MDCT scans were obtained with eight-detector CT; 5 mm thick axial images and 2.5 mm thick coronal multiplanar reconstruction (MPR) images were generated for all patients. Contrast enhancement was performed in 44 of the 155 patients. Two board-certified radiologists reviewed the images for direct findings (free air, ruptured GI tract wall) and indirect findings (inflammatory changes, fluid collection, focal thickening of the GI tract wall) and attempted to identify the perforation site in each patient. RESULTS: Free air was seen in more than 95% of the patients with perforation at sites other than the appendix; free air was seen in 44% of patients with appendicitis. On contrast-enhanced CT performed in 44 patients, rupture of the wall of the GI tract was directly visualized in 14 (32%) on axial images only and in 23 (52%) on axial or MPR images, respectively. The perforation site was correctly diagnosed in 90% of the patients when the radiologists referred to both direct and indirect findings. CONCLUSION: MDCT was valuable for identifying the presence and level of GI tract perforation.

Evaluation of diffusion-weighted imaging for the differential diagnosis of poorly contrast-enhanced and T2-prolonged bone masses: Initial experience.

PURPOSE: To determine whether quantitative diffusion-weighted imaging (DWI) is useful for characterizing poorly contrast-enhanced and T2-prolonged bone masses. MATERIALS AND METHODS: We studied 20 bone masses that showed high signal intensity on T2-weighted images and poor enhancement on contrast-enhanced T1-weighted images. These included eight solitary bone cysts, five fibrous dysplasias, and seven chondrosarcomas. To analyze diffusion changes we calculated the apparent diffusion coefficient (ADC) for each lesion. RESULTS: The ADC values of the two types of benign lesions and chondrosarcomas were not significantly different. However, the mean ADC value of solitary bone cysts (mean +/-SD, 2.57 +/- 0.13 x 10(-3) mm(2)/second) was significantly higher than that of fibrous dysplasias and chondrosarcomas (2.0 +/- 0.21 x 10(-3) mm(2)/second and 2.29 +/- 0.14 x 10(-3) mm(2)/second, respectively, P < 0.05). None of the lesions with ADC values lower than 2.0 x 10(-3) mm(2)/second were chondrosarcomas. CONCLUSION: Although there was some overlapping in the ADC values of chondrosarcomas, solitary bone cyst, and fibrous dysplasia, quantitative DWI may aid in the differential diagnosis of poorly contrast-enhanced and T2-prolonged bone masses.

Signal intensity of the normal pontine tegmentum on T2-weighted MR imaging.

On T2-weighted MR images, the pontine tegmentum frequently shows a signal of high intensity in neurologically healthy individuals. We examined whether the signal intensity of the pontine tegmentum normally differs from that of the pontine base. We evaluated the signal intensity of the pontine tegmentum and pontine base on T2-weighted images from 38 neurologically healthy subjects. The subjects included 29 adults (16 males and 13 females, age range 23-48 years, mean age 39.5 years) and 9 children (4 boys and 5 girls (age range 4-9 years mean age 6.5 years). We compared the contrast-to-noise ratio (CNR) between the tegmentum and the base in the upper pons, midpons and lower pons, and evaluated the signal intensity ratio of the tegmentum to the base. The CNR was significantly higher for the tegmentum than the base at each level of the pons (P<0.0001), and the signal intensity ratio of the tegmentum to the base in the upper pons was significantly higher in children than in adults (P<0.005). On T2-weighted images, a high signal intensity of the pontine tegmentum is frequently seen in neurologically healthy subjects. This finding should not be considered abnormal, particularly in children.

Added value of SPECT/CT fusion in assessing suspected bone metastasis: comparison with scintigraphy alone and nonfused scintigraphy and CT.

PURPOSE: To evaluate retrospectively if there is additional diagnostic value of fused single photon emission computed tomographic (SPECT) and computed tomographic (CT) images in assessing possible bone metastases. MATERIALS AND METHODS: Institutional review board approval was obtained, and each patient provided written informed consent. Bone scintigraphy--including planar and SPECT imaging-and CT were performed with a combined SPECT/CT system in 45 oncologic patients (24 men, 21 women; mean age, 64.7 years +/- 8.7), with a total of 42 metastatic bone foci and 40 benign foci. The reference standard was follow-up radiologic imaging. Two independent readers first analyzed only bone scintigraphic images and next analyzed two separate sets of bone scintigraphic and CT images. They then analyzed bone scintigraphic, CT, and fused images and focused on the additional value of fused images. Diagnostic confidence for each lesion was scored. The three analyses were performed 7 days apart, and the images were presented in random order at each session. The value of additional fused images was assessed by using receiver operating characteristic analysis. RESULTS: After review of fused images to classify indeterminate lesions, reviewer 1 became more confident in diagnosis of the 15 benign lesions and two metastases, and reviewer 2 became more confident in diagnosis of the seven benign lesions and one metastasis. The area under the receiver operating characteristic curve for reviewer 1 was 0.589 for scintigraphic images, 0.831 for separate data sets of scintigraphic and CT images, and 0.947 for fused images. The corresponding areas under the receiver operating characteristic curve for reviewer 2 were 0.771, 0.885, and 0.968, respectively. CONCLUSION: Results demonstrate the increased diagnostic confidence obtained with fused SPECT/CT images compared with separate sets of scintigraphic and CT images in differentiating malignant from benign bone lesions.

Abdominal CT with low tube voltage: preliminary observations about radiation dose, contrast enhancement, image quality, and noise.

PURPOSE: To prospectively investigate the effect of low tube voltage on radiation dose, contrast enhancement, image quality, and image noise at abdominal dynamic computed tomography (CT). MATERIALS AND METHODS: The institutional review board approved this study. Prior informed consent was obtained from all patients. Forty patients (24 women, 16 men; mean age, 62 years) underwent initial abdominal CT at 120 kV with 100 mL of contrast material (protocol A). Then all patients were randomly assigned to one of two protocols (protocol B, CT at 90 kV with 100 mL contrast material; protocol C, CT at 90 kV with 80 mL contrast material). The CT numbers of their abdominal organs were assessed quantitatively and qualitatively. Statistical analysis was performed by using the two-tailed paired t test, Kruskal-Wallis test, and kappa test of interobserver agreement. The radiation dose was measured with a phantom that consisted of glass-rod dosimeters. RESULTS: Quantitative analysis revealed that protocols B and C yielded significantly better enhancement of the aorta, liver, pancreas, spleen, and kidney than did protocol A (P < .05). With qualitative analysis, the difference among the three protocols in regard to image quality was not significant. At 90 kV versus 120 kV, the radiation dose reduction in the center of the phantom was 56.8% (6.3 vs 14.6 mGy); in the periphery, it was 46.2% (13.6 vs 25.3 mGy). CONCLUSION: By decreasing the tube voltage, the amount of contrast material can be reduced without image quality degradation. In scans obtained with a low tube voltage, the radiation dose can be reduced as much as 56.8%, and higher contrast material enhancement can be achieved.

5-fluorouracil intra-arterial infusion combined with systemic gemcitabine for unresectable pancreatic cancer.

OBJECTIVES: The aim of this study was to define assessment of response and adverse events of the combination chemotherapy of 5-fluorouracil (5-FU) pancreatic and hepatic arterial continuous infusion and systemic gemcitabine administration for unresectable pancreatic cancer. METHODS: We treated 24 chemotherapy-naive patients with unresectable pancreatic cancer. To prevent gastroduodenal injury from 5-FU infusion, the catheter was placed to allow the distribution of 5-FU to the pancreatic tumor and the liver after occlusion of the gastric and pancreaticoduodenal arteries. 5-FU was administered at a dose of 250 mg/d on days 1 to 5 every week as a continuous arterial infusion. Gemcitabine was infused intravenously at a dose of 1000 mg once weekly for 3 consecutive weeks of every 4 weeks. RESULTS: The partial response rate was 20.8% (5 of 24), although there was no case of complete response. Fourteen cases (58.3%) were stable disease, and 5 cases (20.8%) were progressive disease. The most common toxicities were hematological and gastrointestinal events. No patients died of adverse effects using this chemotherapy. Gastric and/or duodenal ulcers occurred because of 5-FU intra-arterial infusion. Catheter-related cholangitis occurred in patients with biliary drainage for obstructive jaundice. Median survival time was 14 months, with a 50.9% 1-year survival rate, although patients with performance status 2 and multiple organ metastases had a poor prognosis. CONCLUSIONS: This combination chemotherapy was well tolerated and seemed to be effective for patients with unresectable pancreatic cancer.