18-F fluorodeoxyglucose uptake in positron emission tomography as a pathological grade predictor for renal clear cell carcinomas

OBJECTIVES

To evaluate the usefulness of Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18-F FDG-PET/CT) in the prediction of Fuhrman pathological grades of renal clear cell carcinoma (cRCC).

METHODS

This retrospective study was approved by our institutional review board, and written informed consent was waived. Thirty-one patients with pathologically proven cRCC underwent 18-F FDG-PET/CT for tumour staging. Maximum standardized uptake value of cRCC (tumour SUVmax) and mean SUV of the liver and spleen (liver and spleen SUVmean) were measured by two independent observers. Tumour SUVmax, tumour-to-liver SUV ratio, and tumour-to-spleen SUV ratio were correlated with the pathological grades.

RESULTS

Logistic analysis demonstrated that only the tumour-to-liver SUV ratio was a significant parameter for differentiating high-grade (Fuhrman grades 3 and 4) tumours from low-grade (Fuhrman grades 1 and 2) tumours (P = 0.007 and 0.010 for observers 1 and 2, respectively). Sensitivity, specificity, and positive and negative predictive values for detecting tumours of Fuhrman grades 3 and 4 were 64, 100, 100, and 77%, respectively, for observer 1, and 79, 88, 85, and 83%, respectively, for observer 2.

CONCLUSIONS

The tumour-to-liver SUV ratio with 18-F FDG-PET/CT appeared to be a valuable imaging biomarker in the prediction of high-grade cRCC.

KEY POINTS

• Tumour SUV max was correlated with the Fuhrman grades. • High-grade tumours have significantly higher SUV max than low-grade tumours. • Tumour-to-liver SUV ratio is useful in the prediction of high-grade cRCC.

Multiphase contrast-enhanced magnetic resonance imaging features of Bacillus Calmette-Guérin-induced granulomatous prostatitis in five patients

OBJECTIVE

To evaluate the multiphase contrast-enhanced magnetic resonance (MR) imaging features of Bacillus Calmette-Guérin (BCG)-induced granulomatous prostatitis (GP).

MATERIALS AND METHODS

Magnetic resonance images obtained from five patients with histopathologically proven BCG-induced GP were retrospectively analyzed for tumor location, size, signal intensity on T2-weighted images (T2WI) and diffusion-weighted images (DWI), apparent diffusion coefficient (ADC) value, and appearance on gadolinium-enhanced multiphase images. MR imaging findings were compared with histopathological findings.

RESULTS

Bacillus Calmette-Guérin-induced GP (size range, 9-40 mm; mean, 21.2 mm) were identified in the peripheral zone in all patients. The T2WI showed lower signal intensity compared with the normal peripheral zone. The DWIs demonstrated high signal intensity and low ADC values (range, 0.44-0.68 × 10(-3) mm(2)/sec; mean, 0.56 × 10(-3) mm(2)/sec), which corresponded to GP. Gadolinium-enhanced multiphase MR imaging performed in five patients showed early and prolonged ring enhancement in all cases of GP. Granulomatous tissues with central caseation necrosis were identified histologically, which corresponded to ring enhancement and a central low intensity area on gadolinium-enhanced MR imaging. The findings on T2WI, DWI, and gadolinium-enhanced images became gradually obscured with time.

CONCLUSION

Bacillus Calmette-Guérin-induced GP demonstrates early and prolonged ring enhancement on gadolinium-enhanced MR imaging which might be a key finding to differentiate it from prostate cancer.

Whole-body CT with high heat-capacity X-ray tube and automated tube current modulation--effect of tube current limitation on contrast enhancement, image quality and radiation dose

PURPOSE

To evaluate the effect of tube current limitation on contrast enhancement, image quality, and radiation dose in whole-body 64-detector CT with a high heat-capacity X-ray tube and automated tube current modulation.

MATERIALS AND METHODS

One hundred eighteen patients were randomized into three whole-body CT protocols: tube current limitation at 210 mA, 450 mA, and no limitation. Signal-to-noise ratio (SNR), dose-length product (DLP), estimated effective dose (ED), and image quality were assessed.

RESULTS

Mean SNR of aorta was comparable among protocols, but that of liver was somewhat lower in 210-mA than in 450-mA and no-limitation protocols (p<0.05). Mean DLP with 210-mA (533.8 mGy cm) was reduced by 31% from that with 450-mA (768.4 mGy cm) and by 38% from that with no-limitation protocol (861.3 mGy cm), respectively. Image quality was slightly degraded (p<0.017) with 210 mA relative to the others in thorax and pelvis, but no difference was found in diagnostic acceptability.

CONCLUSION

For whole-body CT using multidetector CT mounted with a high heat-capacity X-ray tube, an appropriate tube current limitation setting may help reduce excessive radiation dose without significant compromise in diagnostic acceptability.

Characterizing focal hepatic lesions by free-breathing intravoxel incoherent motion MRI at 3.0 T

BACKGROUND

Diffusion-weighted (DW) imaging is commonly used to distinguish between benign and malignant liver lesions.

PURPOSE

To prospectively evaluate the true molecular-diffusion coefficient (D), perfusion-related diffusion coefficient (D*), perfusion fraction (f), and ADC of focal hepatic lesions using a free-breathing intravoxel incoherent motion (IVIM) DW sequence, and to determine if these parameters are useful for characterizing focal hepatic lesions.

MATERIAL AND METHODS

One hundred and twenty hepatic lesions (34 metastases, 32 hepatocellular carcinoma [HCC], 33 hemangiomas, and 21 liver cysts) in 74 patients were examined. Mean D, D*, f, and ADC values of hepatic lesions were compared among pathologies. ROC curve analyses were performed to assess the performances of D, D*, f, and ADC values for the characterization of liver lesions as benign or malignant.

RESULTS

The mean D and ADC values of benign lesions were greater than those of malignant lesions (P < 0.001). Although the mean D and ADC values of liver cysts were greater than those of hemangiomas (P < 0.001), and these values were not significantly different between metastases and HCCs (P = 0.99). Area under the ROC curve for ADC values (0.98) was significantly greater (P = 0.048) than that for D values (0.96) for the differentiation of benign and malignant lesions. Sensitivity and specificity for the detection of malignant lesion were 89% and 98%, respectively, when an ADC cut-off value of 1.40 was applied.

CONCLUSION

D and ADC values have more potential for characterizing focal hepatic lesions than D* or f values, and for the differentiation of malignancy and benignity.

Reducing iodine load in hepatic CT for patients with chronic liver disease with a combination of low-tube-voltage and adaptive statistical iterative reconstruction

PURPOSE

To prospectively assess the effect of reduced iodine load to contrast enhancement, image quality, and detectability of hepatocellular carcinomas (HCCs) in hepatic CT with a combination of 80 kVp tube voltage setting and adaptive statistical iterative reconstruction (ASIR) technique in patients with chronic liver disease.

MATERIALS AND METHODS

This HIPAA-compliant study was approved by our institutional review board and written informed consent was obtained in all patients. During a recent 9-month period, 170 consecutive patients (114 men and 56 women; age range, 40-85 years; mean, 67.7 years) with suspected chronic liver diseases were randomized into three CT groups according to the following iodine-load and tube-voltage protocols: 600 milligram per kilogram body weight (mg/kg) iodine load and 120 peak kilovolt (kVp) tube voltage setting (600-120 group), 500 mg/kg and 80 kVp (500-80 group), and 400mg/kg and 80 kVp (400-80 group). Analysis of variance was conducted to evaluate differences in CT number, background noise, signal-to-noise ratio (SNR), effective dose, HCC-to-liver contrast-to-noise ratio (CNR), and figure of merit (FOM). Sensitivity, specificity, and area under the receiver-operating-characteristic curve (AUC) were compared to assess the detectability of HCCs.

RESULTS

Vascular and hepatic enhancement in the 400-80 and 500-80 groups was comparable to or greater than that in the 600-120 group (P<.05). Subjective image quality was comparable among the three groups. Sensitivity, specificity, and AUC for detecting HCCs were comparable among the groups. The effective dose was kept low (3.3-4.1 mSv) in all three groups.

CONCLUSION

Iodine load can be reduced by 33% in CT of the liver with a combination of 80 kVp tube voltage setting and ASIR technique, without compromising the contrast enhancement, image quality, and detection of HCCs.

Peritoneal chronic inflammatory mass formation due to gallstones lost during laparoscopic cholecystectomy

We here describe the radiologic findings of peritoneal chronic abscess formation due to gallstones lost within the peritoneum during laparoscopic cholecystectomy (LC). A radiologic workup 7 months after LC revealed a soft-tissue mass with contrast enhancement, harboring internal necrosis and punctate calcium located in the Morrison's pouch. The mass exhibited restricted water molecule diffusion, absence of fat deposition, and increased F-18 fluorodeoxy-D-glucose uptake, thus mimicking a malignant tumor. The biopsy revealed an inflammatory granuloma. Another patient with similar findings was treated with percutaneous abscess drainage. Thus, radiologists should be aware of this disease condition and its imaging findings.

Whole-body CT screening: scan delay and contrast injection duration for optimal enhancement of abdominal organs and deep vessels

PURPOSE

To assess the optimal scan delays and contrast injection durations for contrast-enhanced whole-body computed tomography (CT).

MATERIALS AND METHODS

One hundred forty-two patients were randomized into three groups: protocol A-scan delay of 65 s after starting contrast injection over 30 s; protocol B-105 and 70 s; and protocol C-145 and 110 s, respectively. Contrast enhancement and diagnostic acceptability were assessed.

RESULTS

Qualitative assessment was subtle among the three protocols. Homogenous enhancement of deep veins was more assuredly achieved with protocol C.

CONCLUSION

With protocol C, qualitatively acceptable enhancement can be obtained in whole-body CT.

A prospective, randomized, double-blind, controlled trial on the efficacy of carbon dioxide insufflation in gastric endoscopic submucosal dissection

BACKGROUND AND STUDY AIMS

Carbon dioxide (CO2) insufflation is expected to be safe and effective in endoscopic submucosal dissection (ESD) as well as in other endoscopic procedures. The present study aimed to clarify the usefulness and safety of CO2 insufflation in gastric ESD.

PATIENTS AND METHODS

A total of 102 consecutive patients were randomly assigned to CO2 insufflation (CO2 group, n = 54) or air insufflation (Air group, n = 48). Abdominal pain and distension were chronologically recorded on a 100-mm visual analog scale (VAS). The volume of residual gas in the digestive tract was measured by computed tomography performed immediately after ESD.

RESULTS

Abdominal pain on a 100-mm VAS in the CO2 vs. Air group was 4 vs. 3 immediately after ESD, 4 vs. 4 one hour after the procedure, 3 vs. 3 three hours after the procedure, and 1 vs. 4 the next morning, showing no difference between the groups. In addition, there was no difference in abdominal distension on the 100-mm VAS over the time course of the study. The volume of residual gas in the digestive tract in the CO2 group was significantly smaller than that in the Air group (643 mL vs. 1037 mL, P < 0.001). The dose of sedative drugs did not differ between the groups. Neither the incidences of complications nor clinical courses differed between the groups.

CONCLUSIONS

Compared with air insufflation, CO2 insufflation during gastric ESD significantly reduced the volume of residual gas in the digestive tract but not the VAS score of abdominal pain and distension.

Fibrosis and postoperative fistula of the pancreas: correlation with MR imaging findings--preliminary results

PURPOSE

To assess the potential value of magnetic resonance (MR) imaging in evaluating pancreatic fibrosis and predicting the development of postoperative pancreatic fistula.

MATERIALS AND METHODS

This retrospective study had institutional review board approval, and the requirement for informed consent was waived. MR images obtained in 29 consecutive patients (15 men, 14 women; mean age, 64.9 years; age range, 21-80 years) who underwent pancreatectomy were evaluated. The pancreas-to-muscle signal intensity (SI) ratio on unenhanced T1- and T2-weighted, dynamic contrast material-enhanced, and diffusion-weighted images and the apparent diffusion coefficient (ADC) of the pancreas were measured. MR imaging parameters were correlated with the degrees of pancreatic fibrosis and expression of activated pancreatic stellate cells (PSCs) by using univariate and multivariate regression analyses and receiver operating characteristic curve analysis. The relationships between the development of postoperative pancreatic fistula and the MR imaging measurements were examined by using logistic regression analysis and the Mann-Whitney U test.

RESULTS

Multiple regression analysis showed that pancreas-to-muscle SI ratios on T1-weighted images and ADC values were independently associated with pancreatic fibrosis (r(2) = 0.66, P < .001) and with activated PSC expression (r(2) = 0.67, P < .001). The mean pancreas-to-muscle SI ratio (± standard deviation) on T1-weighted images was higher (P = .0029) for patients with postoperative pancreatic fistula (1.6 ± 0.2) than for those without (1.2 ± 0.2), and the odds ratio for postoperative pancreatic fistula was 21.3 in patients with an SI ratio of 1.41 and higher.

CONCLUSION

The pancreas-to-muscle SI ratio on T1-weighted MR images of the pancreas may be a potential biomarker for assessment of pancreatic fibrosis and prediction of postoperative pancreatic fistula.

Diffusion/perfusion MR imaging of the liver: practice, challenges, and future

Diffusion-weighted (DWI) magnetic resonance (MR) imaging is useful in diagnosing various pathologic conditions in the liver, such as malignant tumors or hepatic fibrosis, and is now part of routine MR imaging protocols for the liver following the development of a parallel encoding technique that has markedly improved image quality. DWI is not very sensitive for detecting hepatocellular carcinomas (HCC) and is useless for characterizing border-line hepatocellular nodules in cirrhosis, but it complements gadolinium-enhanced MR imaging in detecting regional tumor recurrence or intrahepatic metastases of HCC following treatment. DWI is more useful for detecting hepatic metastasis, because histopathologic architecture of metastases does not resemble that of liver tissue and T(2) relaxation time of hepatic metasitasis is fairly longer than that of liver parenchyma. DWI is also useful for detecting moderate and advanced hepatic fibrosis. In cirrhosis, however, decreased blood flow in fibrotic liver is thought to lower apparent diffusion coefficient of the liver. For MR perfusion analysis, a dual-input one-compartment model is used to correlate various hepatic blood flow parameters that represent hepatic arterial/portal blood flow or fraction, mean transit time, and distribution volume with the severity of cirrhosis and portal hypertension. Conventional multisectional imaging and perfusion study can be combined using a 3-dimensional sequence with high temporal resolution, but spatial resolution is not sufficiently high to diagnose tiny hepatic lesions. The advent of liver-specific contrast agents, such as gadoxetic acid, may spur the development of a new analysis model that incorporates extracellular perfusion and hepatocyte function.

COX/PGE(2) axis critically regulates effects of LPS on eosinophilia-associated cytokine production in nasal polyps

BACKGROUND

Lipopolysaccharide (LPS) has shown heterogeneous effects on eosinophilic inflammation in airways. However, little is known about how LPS regulates pathogenesis of chronic rhinosinusitis with nasal polyps, a major form of eosinophilic inflammation in the upper airway.

OBJECTIVE

We sought to investigate the effect of LPS on cytokine production by dispersed nasal polyp cells (DNPCs).

METHODS

Either diclofenac-treated or untreated DNPCs were cultured with or without staphylococcal enterotoxin B (SEB) in the presence or absence of LPS, after which the levels of IL-5, IL-13, IL-17A and IFN-γ within the supernatant were measured. The effects of PGE(2) on LPS-induced responses by diclofenac-treated DNPCs were also examined. LPS-induced PGE(2) production and mRNA expression of COX-1, COX-2 and microsomal PGE(2) synthase-1 (m-PGES-1) were measured.

RESULTS

Staphylococcal enterotoxin B induced IL-5, IL-13, IL-17A and IFN-γ production by DNPCs. Pre-treatment with LPS prior to SEB stimulation inhibited production of these cytokines. After stimulation with LPS, PGE(2) production and expression of COX-2 and m-PGES-1 mRNA by DNPCs increased significantly. In the presence of diclofenac, the suppressive effects of LPS were eliminated. LPS pre-treatment enhanced SEB-induced IL-5, IL-13 and IL-17A production in diclofenac-treated DNPCs, while addition of PGE(2) inhibited IL-5, IL-13 and IFN-γ production. LPS alone induced IL-5, IL-13 and IFN- γ production by diclofenac-treated DNPCs, while the addition of EP2 and EP4 receptor-selective agonists, as well as PGE(2) itself, inhibited IL-5 and IL-13 production.

CONCLUSIONS AND CLINICAL RELEVANCE

These results suggest that the regulatory effects of LPS on eosinophilic airway inflammation are controlled via the COX-2/PGE(2) axis. For clinical implications, indiscreet use of non-steroidal anti-inflammatory drugs should be avoided in patients with chronic rhinosinusitis with nasal polyps.

Immunization with outer membrane protein A from Salmonella enterica serovar Enteritidis induces humoral immune response but no protection against homologous challenge in chickens

Vaccination of poultry is one promising strategy to mitigate Salmonella infection in poultry and, in turn, humans as well. We evaluated the efficacy of outer membrane protein A (OmpA) as a novel vaccine candidate against Salmonella in poultry. Native OmpA purified from Salmonella enterica serovar Enteritidis was mixed with adjuvant and administered intramuscularly to 41-d-old chicks. The vaccinated birds showed no decrease in cecal excretion and tissue colonization compared with the unvaccinated birds after oral challenge with 10(9) cfu of the homologous strain at 28 d postimmunization. However, this vaccination induced an increased level of serum anti-OmpA IgG. Similar results were obtained in the replication experiments using a recombinant OmpA with single and double doses. For the development of more effective component vaccines for avian salmonellosis, the vaccine efficacy of outer membrane proteins other than OmpA and route of immunization other than parenteral administration should be evaluated with regard to protection and immune responses, including mucosal IgA.

Enhancement of anatomical structures and detection of metastatic cervical lymph nodes: comparison of two different contrast material doses

PURPOSE

To determine if a 20 % reduction in the contrast material dose is acceptable in the CT evaluation of patients with head and neck malignancy.

MATERIALS AND METHODS

Sixty consecutive patients (mean age 67 years) with head and neck malignancy underwent contrast-enhanced CT according to two different protocols: protocol A (80 mL of contrast material administered at an injection rate of 1.5 mL/s) and protocol B (100 mL at 1.9 mL/s). The enhancement of anatomical structures and detectability of metastatic nodes were compared between the two protocols. Pathologic analysis of the surgical resection served as the reference standard.

RESULTS

CT numbers of the anatomical structures were not significantly different between the two protocols. Mean sensitivity (64 and 77 % for protocols A and B, respectively), specificity (78 and 84 %), and accuracy (74 and 83 %) tended to be higher for protocol B than for A, but no significant difference was found.

CONCLUSION

Reducing the contrast material dose by 20 % did not significantly impair the enhancement of anatomical structures or the detection of metastatic cervical lymph nodes. Radiologists should therefore consider reducing the contrast material dose used in head and neck CT.

Mesenteric phlebosclerosis associated with long-term oral intake of geniposide, an ingredient of herbal medicine

BACKGROUND

Idiopathic mesenteric phlebosclerosis (IMP) is a rare disease, characterised by thickening of the wall of the right hemicolon with calcification of mesenteric veins. However, the aetiology remains unknown.

AIM

To investigate the possible association of herbal medicines with IMP.

METHOD

The clinical data of four of our own patients were collected. Furthermore, we searched for previous reports about similar patients with detailed descriptions of herbal prescriptions that they had taken. We compared herbal ingredients to identify the toxic agent as a possible aetiological factor.

RESULTS

Clinical data on a total of 25 patients were summarised. Mean age was 61.8 years and there was female predominance (6 men and 19 women). The used Kampo prescription, the number of cases, and the mean duration of use were as follows: kamisyoyosan in 12 cases for 12.8 years, inshin-iseihaito in 5 cases for 13.4 years, orengedokuto in 4 cases for 14.3 years, inchinkoto in 1 case for 20 years, kamikihitou in 1 case for 19 years, seijobofuto in 1 case for 10 years and gorinsan in 1 case for an unknown duration. Only one ingredient, sansisi, was common to the herbal medicines of all 25 patients. This crude drug called geniposide in English is a major constituent of the Gardenia fruits.

CONCLUSION

The long-term use of geniposide in herbal medicines appears to be associated with mesenteric phlebosclerosis.

A pilot study to assess mediastinal emphysema after esophageal endoscopic submucosal dissection with carbon dioxide insufflation

BACKGROUND AND AIMS

Mediastinal emphysema sometimes develops following esophageal endoscopic submucosal dissection (ESD) without perforation because the esophagus has no serosa. Carbon dioxide (CO2) insufflation during esophageal ESD may reduce the incidence of mediastinal emphysema. The aim of the present study was to compare the incidence and severity of post-ESD mediastinal emphysema in patients receiving CO2 insufflation vs. standard air insufflation during esophageal ESD.

PATIENTS AND METHODS

A total of 27 patients who had undergone esophageal ESD with insufflation of CO2 between July 2009 and March 2010 were enrolled in this study (CO2 group). Another 105 patients who had undergone esophageal ESD with air insufflation between March 2004 and May 2009 were included as historical controls (air group). Multi-detector row computed tomography (MDCT) was carried out immediately after ESD. A conventional chest radiograph was taken the next day. Mediastinal emphysema findings on MDCT and radiography were compared between the groups.

RESULTS

Mediastinal emphysema detected by chest radiography was 0 % in the CO2 group vs. 6.6 % in the air group (n.s.). Mediastinal emphysema on MDCT was significantly less frequent in the CO2 group compared with the air group (30 % vs. 63 %; P = 0.002). The severity of mediastinal emphysema also tended to be lower in the CO2 group.

CONCLUSIONS

Whereas mediastinal emphysema detected by radiography is not so common, MDCT immediately after ESD revealed a certain prevalence of post-ESD mediastinal emphysema. Insufflation of CO2 rather than air during esophageal ESD significantly reduced postprocedural mediastinal emphysema. CO2 can be considered as insufflating gas for esophageal ESD.