Metformin is a kind of biguanide hypoglycemic agent that has been widely used in patients with diabetes mellitus. In clinical practice, whether metformin should be stopped before Fundus fluorescein angiography (FFA) remains largely unclear. Some endocrinologists suggest stop metformin before FFA. However, ophthalmologists do not always adopt this opinion in their practice. This situation may lead to disputes between physicians and patients. This article analyzed contrast-induced nephropathy(CIN) and the related contrast agent, as well as the adverse reactions of fluorescein angiography. It pointed out that the discrepancy may be caused by misunderstanding of contrast agents used in FFA. For angiography using iodine contrast agent, metformin must be stopped because of the increased possibility of CIN, while for FFA using fluorescein sodium, no CIN has been reported yet. Therefore, the authors believe FFA is safe for diabetic patients with oral metformin and it is unnecessary to stop metformin before the examination.
Administration, Oral ; Contrast Media ; adverse effects ; Diabetes Mellitus, Type 2 ; diagnostic imaging ; drug therapy ; Diabetic Retinopathy ; diagnostic imaging ; Fluorescein Angiography ; adverse effects ; methods ; Humans ; Hypoglycemic Agents ; therapeutic use ; Kidney Diseases ; chemically induced ; Metformin ; therapeutic use

BACKGROUND/AIMS: To evaluate the enhancement patterns of liver metastases and their influencing factors using dynamic contrast-enhanced ultrasound (CEUS). METHODS: A total of 240 patients (139 male and 101 female; 58.5±11.2 years of age) diagnosed with liver metastases in our hospital were enrolled in this study to evaluate tumor characteristics using CEUS. A comparison of enhancement patterns with tumor size and primary tumor type was performed using the chi-square test. The differences between quantitative variables were evaluated with the independent-sample t-test and one-way analysis of variance. RESULTS: The enhancement patterns of liver metastases on CEUS were categorized as diffuse homogeneous hyperenhancement (133/240, 55.4%), rim-like hyperenhancement (80/240, 33.3%), heterogeneous hyperenhancement (10/240, 4.2%), and isoenhancement (17/240, 7.1%). There were significant differences in the enhancement patterns during the arterial phase based on the nodule size (p=0.001). A total of 231 of the nodules showed complete washout during the portal phase, and 237 nodules were hypoenhanced during the delayed phase. The washout time was correlated with tumor vascularity, with a longer washout time observed in hypervascular metastases compared to hypovascular metastases (p=0.033). CONCLUSIONS: Diffuse homogeneous hyperenhancement followed by rapid washout was the most common enhancement pattern of liver metastases on CEUS and was affected by the nodule size and tumor vascularity. Small metastases were prone to show diffuse homogeneous hyperenhancement. Hyper-vascular metastases showed a significantly longer washout time compared to hypovascular metastases.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Contrast Media/*therapeutic use ; Female ; Humans ; Liver/diagnostic imaging/pathology ; Liver Neoplasms/blood supply/*diagnostic imaging/secondary ; Male ; Middle Aged ; Neovascularization, Pathologic/diagnostic imaging ; Ultrasonography/*methods ; Young Adult

Preoperative detection of lymph nodes (LNs) metastasis is always highly challenging for radiologists nowadays. The utility of quantitative dynamic contrast-enhanced magnetic resonance imaging (QDCE-MRI) in identifying LNs metastasis is not well understood. In the present study, 59 patients with histologically proven rectal carcinoma underwent preoperative QDCE-MRI. The short axis diameter ratio, long axis diameter ratio, short-to-long axis diameter ratio and QDEC-MRI parameters (K(trans), Kep, fPV and Ve) values were compared between the non-metastatic (n=44) and metastatic (n=35) LNs groups based on pathological examination. Compared with the non-metastatic group, the metastatic group exhibited significantly higher short axis diameter (7.558±0.668 mm vs. 5.427±0.285 mm), K(trans) (0.483±0.198 min(-1) vs. 0.218±0.116 min(-1)) and Ve (0.399±0.118 vs. 0.203±0.096) values (all P<0.05). The short-to-long axis diameter ratio, long axis diameter ratio, Kep and fPV values did not show significant differences between the two groups. In conclusion, our results showed that for LNs larger than 5 mm in rectal cancer, there are distinctive differences in the K(trans) and Ve values between the metastatic and non-metastatic LNs, suggesting that QDCE-MRI may be potentially helpful in identifying LNs status.
Contrast Media ; therapeutic use ; Diagnosis, Differential ; Female ; Humans ; Lymph Nodes ; diagnostic imaging ; pathology ; Lymphatic Metastasis ; diagnosis ; diagnostic imaging ; pathology ; Magnetic Resonance Imaging ; Male ; Rectal Neoplasms ; diagnosis ; diagnostic imaging ; pathology

OBJECTIVE: To compare the radiation dose and image quality between standard-dose CT and a low-dose CT obtained with the combined use of an attenuation-based automatic kilovoltage (kV) selection tool (CARE kV) and sinogram-affirmed iterative reconstruction (SAFIRE) for contrast-enhanced CT examination of the liver. MATERIALS AND METHODS: We retrospectively reviewed 67 patients with chronic liver disease in whom both, standard-dose CT with 64-slice multidetector-row CT (MDCT) (protocol A), and low-dose CT with 128-slice MDCT using CARE kV and SAFIRE (protocol B) were performed. Images from protocol B during the portal phase were reconstructed using either filtered back projection or SAFIRE with 5 different iterative reconstruction (IR) strengths. We performed qualitative and quantitative analyses to select the appropriate IR strength. Reconstructed images were then qualitatively and quantitatively compared with protocol A images. RESULTS: Qualitative and quantitative analysis of protocol B demonstrated that SAFIRE level 2 (S2) was most appropriate in our study. Qualitative and quantitative analysis comparing S2 images from protocol B with images from protocol A, showed overall good diagnostic confidence of S2 images despite a significant radiation dose reduction (47% dose reduction, p < 0.001). CONCLUSION: Combined use of CARE kV and SAFIRE allowed significant reduction in radiation exposure while maintaining image quality in contrast-enhanced liver CT.
Adult ; Aged ; Aged, 80 and over ; Body Height ; Body Mass Index ; Body Weight ; Chronic Disease ; Contrast Media/diagnostic use ; Female ; Humans ; Liver/*radiography/ultrasonography ; Male ; Middle Aged ; *Radiation Dosage ; Radiographic Image Interpretation, Computer-Assisted ; Retrospective Studies ; *Tomography, X-Ray Computed

Optical imaging techniques use visual and near infrared rays. Despite their considerably poor penetration depth, they are widely used due to their safe and intuitive properties and potential for intraoperative usage. Optical imaging techniques have been actively investigated for clinical imaging of lymph nodes and lymphatic system. This article summarizes a variety of optical tracers and techniques used for lymph node and lymphatic imaging, and reviews their clinical applications. Emerging new optical imaging techniques and their potential are also described.
Contrast Media/diagnostic use ; Fluorescent Dyes/diagnostic use ; Humans ; Lymph Nodes/pathology/*radiography ; Lymphatic System/*pathology ; Lymphography ; Magnetic Resonance Imaging ; *Optical Imaging ; Positron-Emission Tomography ; Quantum Dots/diagnostic use ; Spectroscopy, Near-Infrared

OBJECTIVE: To assess the effect of chest circumference-adapted scanning protocol on radiation exposure and image quality in patients undergoing prospective electrocardiogram (ECG)-triggered coronary CT angiography (CCTA). MATERIALS AND METHODS: One hundred-eighty-five consecutive patients, who had undergone prospective ECG triggering CCTA with a 128-slice CT, were included in the present study. Nipple-level chest circumference, body weight and height were measured before CT examinations. Patients were divided into four groups based on kV/ref.mAs = 100/200, 100/250, 120/200, and 120/250, when patient's chest circumference was < or = 85.0 (n = 56), 85.0-90.0 (n = 53), 90.0-95.0 (n = 44), and > 95.0 (n = 32), respectively. Image quality per-segment was independently assessed by two experienced observers. Image noise and attenuation were also measured. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The effective radiation dose was calculated using CT dose volume index and the dose-length product. RESULTS: A significant correlation was observed between patients' chest circumference and body mass index (r = 0.762, p < 0.001). Chest circumference ranged from 74 to 105 cm, and the mean effective radiation dose was 1.9-3.8 mSv. Diagnostic image quality was obtained in 98.5% (2440/2478) of all evaluated coronary segments without any significant differences among the four groups (p = 0.650). No significant difference in image noise was observed among the four groups (p = 0.439), thus supporting the validity of the chest circumference-adapted scanning protocol. However, vessel attenuation, SNR and CNR were significantly higher in the 100 kV groups than in the 120 kV groups (p < 0.05). CONCLUSION: A measure of chest circumference can be used to adapt tube voltage and current for individualized radiation dose control, with resultant similar image noise and sustained diagnostic image quality.
Adult ; Aged ; Body Mass Index ; Contrast Media/diagnostic use ; Electrocardiography ; Female ; Heart/*radiography ; Heart Rate ; Humans ; Male ; Middle Aged ; Prospective Studies ; Radiation Dosage ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed/*methods ; *Waist Circumference

PURPOSE: To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT). MATERIALS AND METHODS: The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol. RESULTS: As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture. CONCLUSION: Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture.
*Algorithms ; Artifacts ; Contrast Media/diagnostic use ; Humans ; *Phantoms, Imaging ; Radiation Dosage ; Radiographic Image Interpretation, Computer-Assisted/*methods ; Signal-To-Noise Ratio ; Tomography, X-Ray Computed

OBJECTIVE: Bilateral oophorectomy leads to reduced bone mineral density (BMD), and reduced BMD is associated with increased marrow fat and reduced marrow perfusion. Purpose of this study was to investigate how soon these changes occur following surgical oophorectomy. MATERIALS AND METHODS: Six patients who underwent hysterectomy and bilateral salpingo-oophorectomy were studied. At baseline, mean patient age was 49.5 years (range: 45-54 years). Third lumbar vertebral body BMD measurement using quantitative CT, marrow fat fraction (FF) using MR spectroscopy and marrow perfusion using dynamic contrast enhanced MRI were conducted immediately prior to surgery and at 3, 9, and 21 months after surgery. RESULTS: Reduced BMD, increased marrow FF, and reduced marrow perfusion occurred synchronously post-oophorectomy. There was a sharp decrease of 12.5 +/- 7.2% in BMD (n = 6), a sharp increase of 92.2 +/- 46.3% (n = 6) in FF, a sharp decrease of 23.6 +/- 3.9% in maximum contrast enhancement (n = 5), and of 45.4 +/- 7.7% for enhancement slope (n = 5) during the initial 3 months post surgery. BMD and marrow perfusion continued to decrease, and marrow FF continued to increase at a slower rate during the following 18 months. Friedman test showed a significant trend for these changes (p < 0.05). CONCLUSION: Bilateral oophorectomy leads to a rapid decrease in lumbar BMD, an increase in marrow fat content, and a decrease in marrow blood perfusion.
Body Mass Index ; Bone Density ; Bone Marrow/*metabolism ; Contrast Media/diagnostic use ; Female ; Humans ; Hysterectomy ; Lipids/analysis ; Longitudinal Studies ; Lumbar Vertebrae/*radiography ; *Magnetic Resonance Imaging ; Middle Aged ; Ovariectomy ; Prospective Studies

OBJECTIVE: To conduct signature analysis for splenic trauma in canines during hemorrhagic shock and resuscitation by contrast enhanced ultrasonography (CEUS). METHODS: Forty grade III-IV traumatic splenic lesions were established in 15 mongrel dogs. Hemorrhagic shock was induced in these animals by using the modified Wiggers's method. Animals in shock were then resuscitated with 6% hydroxyethyl starch. The features of splenic trauma during hemorrhagic shock or resuscitation were assessed by CEUS, which were compared with the data collected by contrast-enhanced computed tomography (CECT). Acoustic quantification of CEUS was performed to assess splenic blood perfusion in different stages. RESULTS: There was no significant difference in detection rate between CEUS and CECT during hemorrhagic shock and resuscitation. Before hemorrhagic shock, there were 40 traumatic bleeding lesions and 85% of them were revealed by CEUS (34/40). With the progress in shock, CEUS revealed that the numbers of tiny branches of splenic arteries were decreased, which became thinner with no active bleeding. After fluid resuscitation, rebleeding was occurred in 30 traumatic lesions, and 28 (93.3%) of them were captured by CEUS. CEUS could also visualize the changes in splenic perfusion in different stages. During the shock, the arrival time (AT), time to peak intensity (TTP), peak intensity (PI) were significantly lower and the washout time (WT) were significantly higher than those at other stages (P<0.01). CONCLUSION CEUS not only can dynamically monitor the changes in spleen traumatic hemorrhage and recurrent hemorrhage, but also can quantitatively study the changes in spleen blood perfusion in different stages.
Animals ; Contrast Media ; Disease Models, Animal ; Dogs ; Fluid Therapy ; Hemorrhage ; Hydroxyethyl Starch Derivatives ; therapeutic use ; Resuscitation ; Shock, Hemorrhagic ; pathology ; therapy ; Spleen ; diagnostic imaging ; Tomography, X-Ray Computed ; Ultrasonography

BACKGROUND/AIMS: Inflammatory pseudotumor (IPT) of the liver is a rare disease characterized by chronic infiltration of inflammatory cells. However, the clinical characteristics and outcomes of IPT remain uncertain. METHODS: Clinical features, image findings, and outcomes of 55 patients with histologically proven IPT were evaluated. RESULTS: They consisted of 26 men and 19 women with median age of 65 years. Serum carcinoembryonal antigen and carbohydrate antigen 19-9 levels were normal in 42 patients (93.3%). Enhanced CT scans indicated poorly defined peripheral enhancement (82.5%) at the arterial phase and poorly defined hyperattenuating lesions with internal hypoattenuating areas at the equilibrium phase (77.0%). Gadolinium-enhancement MRI revealed poorly defined peripheral rim-like enhancement (77.8%). Ten patients underwent surgical resection and 35 were treated conservatively with or without antibiotics. No recurrence was noted after surgical resection during follow-up (1 to 48 months). In all patients who received conservative treatment, complete resolution or size reduction was noted during follow-up (1 to 192 months). CONCLUSIONS: CT and MRI provide clues to the diagnosis of IPT in patients with liver masses and normal tumor markers. However, due to the lack of pathognomonic findings, the clinician's suspicion and histological diagnosis are necessary to make an accurate diagnosis of IPT.
Adult ; Aged ; Aged, 80 and over ; Contrast Media/diagnostic use ; Female ; Granuloma, Plasma Cell/*diagnosis/therapy ; Humans ; Liver Diseases/*diagnosis/therapy ; Magnetic Resonance Imaging/methods ; Male ; Middle Aged ; Prognosis ; Tomography, X-Ray Computed/methods