Nanopipette Fabrication Guidelines for SICM Nanoscale Imaging.

Scanning ion conductance microscopy (SICM) is a promising tool for visualizing the dynamics of nanoscale cell surface topography. However, there are still no guidelines for fabricating nanopipettes with ideal shape consisting of small apertures and thin glass walls. Therefore, most of the SICM imaging has been at a standstill at the submicron scale. In this study, we established a simple and highly reproducible method for the fabrication of nanopipettes with sub-20 nm apertures. To validate the improvement in the spatial resolution, we performed time-lapse imaging of the formation and disappearance of endocytic pits as a model of nanoscale time-lapse topographic imaging. We have also successfully imaged the localization of the hot spot and the released extracellular vesicles. The nanopipette fabrication guidelines for the SICM nanoscale topographic imaging can be an essential tool for understanding cell-cell communication.

High-Speed SICM for the Visualization of Nanoscale Dynamic Structural Changes in Hippocampal Neurons.

Dynamic reassembly of the cytoskeleton and structural changes represented by dendritic spines, cargo transport, and synapse formation are closely related to memory. However, the visualization of the nanoscale topography is challenging because of the diffraction limit of optical microscopy. Scanning ion conductance microscopy (SICM) is an effective tool for visualizing the nanoscale topography changes of the cell surface without labeling. The temporal resolution of SICM is a critical issue of live-cell time-lapse imaging. Here, we developed a new scanning method, automation region of interest (AR)-mode SICM, to select the next imaging region by predicting the location of a cell, thus improving the scanning speed of time-lapse imaging. The newly developed algorithm reduced the scanning time by half. The time-lapse images provided not only novel information about nanoscale structural changes but also quantitative information on the dendritic spine and synaptic bouton volume changes and formation process of the neural network that are closely related to memory. Furthermore, translocation of plasmalemmal precursor vesicles (ppvs), for which fluorescent labeling has not been established, were also visualized along with the rearrangement of the cytoskeleton at the growth cone.

The possible clinical impact of risperidone on P-glycoprotein-mediated transport of tacrolimus: A case report and in vitro study.

The authors encountered the case of an 8-fold increase in the concentration/dose (C/D) ratio of tacrolimus (TAC) following the coadministration of voriconazole (VRCZ) in a hematopoietic stem cell transplantation (HSCT) recipient. The interaction observed was much greater than expected and the patient had also been treated with oral risperidone (RSP). It was hypothesized that cytochrome P450 (CYP)3A inhibition of the small intestine by voriconazole and P-glycoprotein (P-gp) inhibition of the small intestine by risperidone exerted a synergistic effect on the bioavailability of tacrolimus. The aim of the present study was to evaluate the effect of risperidone on the P-gp-mediated transport of tacrolimus. The transcellular transport of P-gp substrates was examined in Caco-2 and P-gp-expressing renal epithelial LLC-GA5-COL150 cells. In Caco-2 cells, the apical-basal (A-B) transport of rhodamine123 (Rh123) after a 120 min incubation was increased by 47.1%, whereas that in the B-A direction was decreased by 61.7% in the presence of risperidone (100 µm). These results indicate that risperidone showed an inhibitory effect on the P-gp-mediated transport of Rh123. In LLC-GA5-COL150 cells, the A-B transport of tacrolimus after 120 min incubation was increased by 21.7% in the presence of risperidone (100 µm), whereas that in the B-A direction was decreased by 10.7%. These results suggest that risperidone was at least partly involved in the mechanism of the marked increase in the C/D ratio of tacrolimus. This case report provides new insights into the diversity of drug interactions of tacrolimus triggered by the combination of two concomitant drugs.

In Vitro P-Glycoprotein-Mediated Transport of Tadalafil: A Comparison with Sildenafil.

Tadalafil and sildenafil are selective inhibitors of phosphodiesterase type 5, showing marked pharmacokinetic variability in patients with pulmonary arterial hypertension. It has been reported that sildenafil is a substrate for P-glycoprotein (P-gp), but whether tadalafil is a substrate for P-gp remains to be determined. The objective of the present study was to elucidate whether tadalafil is a substrate for P-gp. Transcellular transport of sildenafil and tadalafil (5 µM each) was examined using renal epithelial LLC-PK1 and P-gp-expressing LLC-GA5-COL150 cell monolayers. The efflux ratio of the basal to apical (B to A) transport of sildenafil to the A to B transport after 120-min incubation in LLC-GA5-COL150 cells (1.52) was significantly higher than that in LLC-PK1 cells (0.711). The efflux ratio of the B to A transport of tadalafil to the A to B transport after 120-min incubation in LLC-GA5-COL150 cells (10.4) was significantly higher than that in LLC-PK1 cells (1.23). In LLC-GA5-COL150 cell monolayers, the Vmax and Km values of sildenafil transport calculated from a modified Michaelis-Menten equation were 101±64 pmol/min/cm2 and 112±47 µM, respectively. On the other hand, those of tadalafil transport were 13.6±4.8 pmol/min/cm2 and 22.7±9.3 µM, respectively. In the presence of a P-gp inhibitor (PSC833), the B to A transport of tadalafil was decreased by 28.6% in LLC-GA5-COL150 cells, and the A to B transport of tadalafil was 6.59-fold greater than that in its absence. These results indicate that tadalafil is a substrate for P-gp.

MR dacryocystography: comparison with dacryoendoscopy in positional diagnosis of nasolacrimal duct obstruction.

PURPOSE: To compare the findings of MR dacryocystography with those of dacryoendoscopy and subsequent surgery in patients with nasolacrimal duct obstruction, and to determine the efficacy of MR dacryocystography in the positional diagnosis of nasolacrimal duct obstruction. MATERIALS AND METHODS: Thirty-one patients with clinically suspected nasolacrimal duct obstruction who underwent MR dacryocystography and dacryoendoscopy with subsequent surgical procedure were included. MR dacryocystography was performed by using heavily T2-weighted fast spin echo sequence in the coronal and axial planes after the topical administration of normal saline drops into the conjunctival sacs. RESULTS: In MR dacryocystography, stenosis/obstruction at the canalicular level was correctly diagnosed in nine patients (100 %). Stenosis/obstruction at the lacrimal sac level was correctly diagnosed in 14 of 16 patients (87.5 %) in MR dacryocystography. Three patients with coexistent stenosis/obstruction at both the canalicular and the lacrimal sac level were misinterpreted as stenosis/obstruction at the canalicular level on MR dacryocystography. The overall accuracy of MR dacryocystography in depicting stenosis/obstruction was 84 %. CONCLUSIONS: MR dacryocystography after the topical administration of normal saline drops into the conjunctival sacs is a well-tolerated, minimally invasive imaging technique to identify the level of stenosis/obstruction in patients with nasolacrimal duct obstruction before dacryoendoscopy and subsequent surgery.

Age-related change in renal corticomedullary differentiation: evaluation with noncontrast-enhanced steady-state free precession (SSFP) MRI with spatially selective inversion pulse using variable inversion time.

PURPOSE: To evaluate age-related change in renal corticomedullary differentiation and renal cortical thickness by means of noncontrast-enhanced steady-state free precession (SSFP) magnetic resonance imaging (MRI) with spatially selective inversion recovery (IR) pulse. MATERIALS AND METHODS: The Institutional Review Board of our hospital approved this retrospective study and patient informed consent was waived. This study included 48 patients without renal diseases who underwent noncontrast-enhanced SSFP MRI with spatially selective IR pulse using variable inversion times (TIs) (700-1500 msec). The signal intensity of renal cortex and medulla were measured to calculate renal corticomedullary contrast ratio. Additionally, renal cortical thickness was measured. RESULTS: The renal corticomedullary junction was clearly depicted in all patients. The mean cortical thickness was 3.9 ± 0.83 mm. The mean corticomedullary contrast ratio was 4.7 ± 1.4. There was a negative correlation between optimal TI for the best visualization of renal corticomedullary differentiation and age (r = -0.378; P = 0.001). However, there was no significant correlation between renal corticomedullary contrast ratio and age (r = 0.187; P = 0.20). Similarly, no significant correlation was observed between renal cortical thickness and age (r = 0.054; P = 0.712). CONCLUSION: In the normal kidney, noncontrast-enhanced SSFP MRI with spatially selective IR pulse can be used to assess renal corticomedullary differentiation and cortical thickness without the influence of aging, although optimal TI values for the best visualization of renal corticomedullary junction were shortened with aging.

High-risk nodules detected in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging in cirrhosis or chronic hepatitis: incidence and predictive factors for hypervascular transformation, preliminary results.

PURPOSE: To evaluate the incidence and predictive factors of hypervascular transformation during follow-up of "high-risk nodules" detected in the hepatobiliary phase of initial Gd-EOB-DTPA-enhanced MRI in chronic liver disease patients. MATERIALS AND METHODS: A total of 109 patients with chronic liver disease who underwent Gd-EOB-DTPA-enhanced MRI several times were investigated. Of these, 43 patients had 76 high-risk nodules with both hypointensity in the hepatobiliary phase and hypovascularity in the arterial phase of initial MRI. These nodules were observed until hypervascularity was detected. MRI and clinical findings were compared to assess the incidence and potential predictive factors for hypervascular transformation between the group showing hypervascular transformation and the group not showing hypervascularization. RESULTS: The median observation period was 242.5 ± 203.2 days (range, 47-802 days). Overall, 24 of 76 high-risk nodules (31.6%) showed hypervascular transformation during follow-up (median observation period, 186.0 ± 190.3 days). The growth rate of the nodules (P < 0.001), the presence of fat within nodules (P = 0.037), and hyperintensity on T1-weighted images (P = 0.018) were significantly correlated with hypervascularization. CONCLUSION: Subsets of high-risk nodules tended to show hypervascular transformation during follow-up, with an increased growth rate, the presence of fat, and hyperintensity on T1-weighted images as predictive factors.

Hypointense hepatocellular nodules on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI: can increasing the flip angle improve conspicuity of lesions?

PURPOSE: To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs). MATERIALS AND METHODS: A total of 95 patients with chronic liver disease who underwent Gd-EOB-DTPA-enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver-to-lesion contrast-to-phantom ratios (CPR) and lesion conspicuity (LCS) were assessed. RESULTS: In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001). CONCLUSION: In the evaluation of hypointense hepatocellular nodules on HP of Gd-EOB-DTPA-enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°.

Simple Method for evaluating the degree of liver parenchymal enhancement in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging.

PURPOSE: To establish a simple method to evaluate the degree of liver parenchymal enhancement in the hepatobiliary phase (HP) of gadoxetic acid-enhanced magnetic resonance imaging (MRI). MATERIALS AND METHODS: Subjects comprised 75 patients with or without chronic liver disease who underwent gadoxetic acid-enhanced MRI and indocyanine green retention at 15 minutes (ICG-R15). HP images were used for data analysis. In the quantitative evaluation, liver-to-phantom signal intensity (SI) ratio (LPR), liver-to-portal vein SI ratio (LPVR), and liver-to-kidney SI ratio (LKR) were calculated. In qualitative visual assessment, liver-to-portal vein contrast (LPVC) and liver-to-kidney contrast (LKC) were assessed using a 5-point scale (1, hyperintense; 2, slightly hyperintense; 3, isointense; 4, slightly hypointense; 5, hypointense). Statistical evaluations included the Spearman's rank correlation test. RESULTS: LPVC and LKC correlated significantly with LPR (ρ = -0.445, P < 0.001; ρ = -0.576, P < 0.001, respectively). LPVC and LKC showed significant correlations with LPVR and LKR (ρ = -0.659, P < 0.001; ρ = -0.674, P < 0.001, respectively). In addition, LPVC and LKC correlated significantly with ICG-R15 (ρ = 0.696, P < 0.001; ρ = 0.795, P < 0.001, respectively). CONCLUSION: LPVC and LKC can be used as simple visual indicators to objectively assess the degree of liver parenchymal enhancement on HP of gadoxetic acid-enhanced MRI.

Peripheral low intensity sign in hepatic hemangioma: diagnostic pitfall in hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI of the liver.

PURPOSE: To describe the presence of "peripheral low intensity sign" in hepatic hemangioma in the hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and to compare the frequency of this sign between hepatic hemangiomas and hepatic metastases. MATERIALS AND METHODS: The Institutional Review Board approved this study and waived the requirement for informed consent. Sixty-four patients with 51 hepatic hemangiomas (n = 31 patients) and with 58 hepatic metastases (n = 33 patients) underwent Gd-EOB-DTPA-enhanced MRI. In all hepatic hemangiomas, 41 lesions were the typical type and 10 were the high flow type. HP images were qualitatively evaluated for the frequency of peripheral low intensity sign in hepatic hemangiomas and hepatic metastases using a four-point scale. Statistical evaluations were performed with a Mann-Whitney U-test. RESULTS: Peripheral low intensity signs were demonstrated in 24 (47%) of 51 hepatic hemangiomas, while they were seen in 27 (47%) of 58 hepatic metastases. There was no significant difference in the mean visual score of peripheral low intensity sign between all hepatic hemangiomas (0.84 ± 1.03) and hepatic metastases (0.76 ± 0.92). The mean visual score of peripheral low intensity sign in typical hemangiomas (1.02 ± 1.06) was significantly higher than that in high flow hemangiomas (0.10 ± 0.32) (P = 0.008). CONCLUSION: Peripheral low intensity sign is not specific for malignant tumors, and can be seen even in hepatic hemangiomas on HP of Gd-EOB-DTPA-enhanced MRI.

Serial 3-dimensional volumetric computed tomography evaluation of lung cancer growth rate in patients with chronic obstructive pulmonary disease findings.

PURPOSE: The objectives of this study were to compare volume doubling time (VDT) of lung cancer with chronic obstructive pulmonary disease (COPD) findings with that without COPD findings using serial 3-dimensional (3D) volumetric computed tomography (CT) and to investigate the association between VDT and COPD findings. METHODS: This study included 45 patients with surgically diagnosed non-small cell lung cancer with serial preoperative follow-up CT. Volume doubling time of the nodule was calculated by using 3D volumetric computer software. RESULTS: Volume doubling time of lung cancer with COPD findings (n = 26) tended to be shorter than that without COPD findings (n = 19) (998 ± 2178 vs 2226 ± 6748 days; P = 0.066). Among COPD findings, severity and pattern of emphysema were significantly correlated with VDT (P < 0.001). CONCLUSIONS: Volume doubling time of lung cancer with COPD findings on 3D volumetric CT tended to be shorter than that of lung cancer without COPD findings. Severe or paraseptal emphysema may be associated with short VDT of lung cancer with COPD findings.

Prostate cancer detection in patients with total serum prostate-specific antigen levels of 4-10 ng/mL: diagnostic efficacy of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging.

OBJECTIVE: The purpose of this study is to evaluate the utility of T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI) for detecting prostate cancer in patients with total serum prostate-specific antigen (PSA) levels of 4-10 ng/mL, which is referred to as the "gray zone." MATERIALS AND METHODS: Fifty patients with gray-zone PSA levels underwent MRI before biopsy. According to the sites of biopsy, the prostate was divided into eight regions on MRI scans. These regions were evaluated individually for the following features: detectability of prostate cancer on per-region and per-patient bases, and relationship between tumor size and positive or negative MRI findings for tumor detection. RESULTS: On a per-region basis, the sensitivity and specificity of tumor detection were 36% and 97% for T2-weighted imaging, 43% and 95% for DCE-MRI, 38% and 96% for DWI, and 53% and 93% for the combined method of MRI, respectively. The sensitivity of combined MRI to detect tumor was significantly higher than those of the individual methods (p < 0.001 to p = 0.001). Tumor size was significantly larger in regions with positive MRI findings than in regions with negative MRI findings (p = 0.004). On a per-patient basis, sensitivity and specificity of combined MRI to detect prostate cancer were 83% and 80%, respectively. CONCLUSION: Combined T2-weighted imaging, DWI, and DCE-MRI findings appear to be potentially useful for detecting and managing prostate cancer, even when performed for patients with gray-zone PSA levels.

Locally recurrent prostate cancer after high-dose-rate brachytherapy: the value of diffusion-weighted imaging, dynamic contrast-enhanced MRI, and T2-weighted imaging in localizing tumors.

OBJECTIVE: The purpose of this article is to retrospectively evaluate the utility of prostate MRI for detecting locally recurrent prostate cancer after high-dose-rate (HDR) brachytherapy. MATERIALS AND METHODS: Sixteen men with biochemical failure after HDR brachytherapy for prostate cancer underwent prostate MRI, including T2-weighted imaging, dynamic contrast-enhanced MRI (DCE-MRI), and diffusion-weighted imaging (DWI), using a 1.5-T MRI unit before 12-core-specimen biopsy. Two radiologists in consensus assessed the presence of tumor on each sequence within eight regions of the prostate (six from the peripheral zone [PZ] and two from the transition zone [TZ]) on the basis of biopsy. RESULTS: Biopsy revealed locally recurrent prostate cancer in 22 (17 in PZ and five in TZ) of 128 regions (17.2%). The sensitivity, specificity, and accuracy of each MRI method in the detection of recurrent tumor were 27%, 99%, and 87%, respectively, for T2-weighted imaging; 50%, 98%, and 90%, respectively, for DCE-MRI; and 68%, 95%, and 91%, respectively, for DWI. The sensitivity of DWI in detecting recurrent tumor was significantly higher than that of T2-weighted imaging (p = 0.004). Multiparametric MRI achieved the highest sensitivity (77%) but with slightly decreased specificity (92%). CONCLUSION: These results indicate that a multiparametric MRI protocol that includes DWI provides a sensitive method to detect local recurrence after HDR brachytherapy.

Dynamic contrast-enhanced CT of the abdomen to predict clinical prognosis in patients with hypovolemic shock.

OBJECTIVE: The objective of our study was to investigate the value of dynamic contrast-enhanced CT (DCE-CT) findings in predicting the clinical prognosis of patients with hypovolemic shock. MATERIALS AND METHODS: This study included 33 patients with hypovolemic shock who underwent DCE-CT of the abdomen due to trauma. The CT attenuation values of several abdominal organs (spleen, liver, pancreas, kidneys [cortex and medulla], adrenal gland) in patients with hypovolemic shock were measured in the early phase and delayed phase to compare the differences in contrast enhancement effects between the survival group and the deceased group. RESULTS: Among the 33 patients with hypovolemic shock, 15 patients died (deceased group) within 5 weeks (mean, 6 days). The remaining 18 patients survived and recovered (survival group). The mean CT attenuation values of the renal medulla in the delayed phase CT in the deceased group (155.4 ± 60.1 [SD] HU) were significantly lower (p = 0.001) than those in the survival group (227.3 ± 47.3 HU). The mean CT attenuation values of the renal medulla in the early phase CT did not show a significant difference between the two groups (102.4 ± 61.7 vs 113.9 ± 43.5 HU, respectively). The mean CT values of the spleen in the early phase CT in the deceased group (90.8 ± 26.0 HU) were significantly lower (p = 0.015) than those in the survival group (119.9 ± 33.9 HU). Regarding other CT measurements, there were no other significant differences between the deceased group and survival group. CONCLUSION: Decreased enhancement of the renal medulla in the delayed phase and decreased enhancement of the spleen in the early phase are useful CT findings to predict a poor clinical prognosis in patients with hypovolemic shock.

Hepatic hemangiomas: evaluation of enhancement patterns at dynamic MRI with gadoxetate disodium.

OBJECTIVE: The aim of this retrospective study was to assess the enhancement patterns of hepatic hemangiomas on gadoxetate disodium. MATERIALS AND METHODS: A total of 22 patients with 32 hepatic hemangiomas (23 typical type and nine high-flow type) in normal liver underwent gadoxetate disodium-enhanced MRI. Contrast-enhanced images were obtained before and after contrast injection, including arterial phase, portal phase, equilibrium phase, and three hepatobiliary phases (10, 15 and 20 minutes). Signal-to-phantom ratios of hemangiomas and the portal vein as well as lesion-to-liver contrast-to-phantom ratios were assessed. RESULTS: Mean signal-to-phantom ratios of all 32 hemangiomas showed the highest value on the arterial phase and subsequently decreased over time (p = 0.029 to p < 0.001). Mean lesion-to-liver contrast-to-phantom ratios of all 32 hemangiomas showed a positive value during the arterial phase and increasingly negative values at later time points (p = 0.001 to p < 0.001). The enhancement pattern of hemangiomas was equal to that of the portal vein at all time points. There was no significant difference in signal-to-phantom ratio between typical hemangiomas and high-flow hemangiomas at any time point. CONCLUSION: Most hepatic hemangiomas showed hypointensity relative to surrounding liver parenchyma during the equilibrium phase and the hepatobiliary phase. In addition, hepatic hemangiomas showed a signal intensity matching the portal vein at all phases, a finding we believe may be characteristic for hepatic hemangiomas on gadoxetate disodium-enhanced MR images.

Adrenal glands in hypovolemic shock: preservation of contrast enhancement at dynamic computed tomography.

PURPOSE: To evaluate contrast enhancement effects of the adrenal glands at dynamic computed tomography (CT) in adult severe trauma patients with hypovolemic shock in comparison with patients without hypovolemic shock. MATERIALS AND METHODS: This study population included a total of 74 patients with (n = 24) and without (n = 50) blunt trauma and hypovolemic shock. Measurement of CT attenuation values of the adrenal gland and calculation of the enhancement washout percentages were performed. RESULTS: The mean +/- SD CT attenuation values of the adrenal glands in the arterial phase of dynamic CT in patients with hypovolemic shock (137.3 +/- 41.7 Hounsfield unit [HU]) were not significantly different (P = 0.16) from those in control subjects (127.3 +/- 19.6 HU). The mean CT attenuation values of the adrenal glands in the delayed phase of dynamic CT in patients with hypovolemic shock (82.0 +/- 14.7 HU) were also not significantly different (P = 0.89) from those in control subjects (82.4 +/- 10.0 HU). The mean percentage (35%) of enhancement washout of the adrenal glands in patients with hypovolemic shock was not significantly different (P = 0.81) from that (34%) in control subjects. CONCLUSIONS: Contrast enhancement effects of the adrenal glands at contrast-enhanced dynamic CT in patients with hypovolemic shock were similar to those in control subjects, indicating the preserved enhancement and perfusion of the adrenal gland rather than intense and persistent enhancement in patients with hypovolemic shock.

Gd-EOB-DTPA-enhanced magnetic resonance imaging findings of nondiffuse fatty change of the liver.

PURPOSE: To evaluate the difference in enhancement effects between the area of fatty change and the area of nonfatty change in patients with nondiffuse fatty change of the liver at gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging. METHODS: Thirteen patients with nondiffuse fatty change of the liver underwent Gd-EOB-DTPA-enhanced MR imaging including dynamic study using a 1.5-T MR unit. Dynamic contrast-enhanced (DCE) MR images were obtained at pre, arterial phase (25 seconds), portal phase (70 seconds), equilibrium phase (3 minutes), and hepatobiliary phase (10, 15, 20 minutes). The percentage differences of signal enhancement ratio were calculated from signal intensity measurement of the liver in each phase of DCE study and were compared between the area of fatty change and the area of nonfatty change in all phases. RESULTS: In the all phases on DCE study, there were no significant differences in the signal enhancement ratio between the area of fatty change (27.7% ± 14.8%, 58.2% ± 14.7%, 62.7% ± 10.6%, 80.4% ± 15.2%, 84.9% ± 16.2%, 88.0% ± 14.3%) and the area of nonfatty change (29.9% ± 16.6%, 54.9% ± 13.3%, 63.0% ± 8.8%, 75.7% ± 12.6%, 80.3% ± 15.7%, 86.4% ± 14.5%) (P = 0.613). CONCLUSIONS: Although our results are limited by the small number of patients, our results showed that the presence of fatty change of the liver did not affect the hepatic contrast enhancement effects of Gd-EOB-DTPA in all phases on dynamic study. This indicates that Gd-EOB-DTPA may be a reliable marker to identify areas of nondiffuse fatty change of the liver.

T2-weighted magnetic resonance imaging of the liver: evaluation of the effect in signal intensity after Gd-EOB-DTPA enhancement.

OBJECTIVE: To evaluate the effect of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) on T2-weighted magnetic resonance imaging of liver parenchyma. METHODS: Forty-six patients with suspected hepatic tumors (group 1) underwent breath-hold T2-weighted fast spin echo imaging before and after 4 minutes of Gd-EOB-DTPA enhancement. Visual assessment and signal intensity (SI) measurements were performed to evaluate the effects of Gd-EOB-DTPA on the T2-weighted images of the liver. Thirteen healthy volunteers (Group 2) who underwent magnetic resonance imaging before and after 35 minutes of Gd-EOB-DTPA enhancement were also evaluated. RESULTS: In the qualitative analysis, visual SI of hepatic vessels after enhancement was significantly higher than that before enhancement (P < 0.001) in group 1, although there was no significant difference in the visual SI of liver parenchyma between before and after enhancement. In the quantitative analysis, SI ratio of liver parenchyma on enhanced images was significantly higher than that on unenhanced images (P < 0.001) in group 1. Conversely, the SI ratio (P < 0.001) and the visual SI (P = 0.008) in group 2 were significantly lower on the enhanced images than on the unenhanced images. CONCLUSIONS: The T2-weighted images obtained during the early phase after enhancement will appear similar to those of the unenhanced T2-weighted images, whereas later images will show a reduced signal of the liver parenchyma.

Kinematic Magnetic Resonance Imaging of the Thorax Using 2-Dimensional Balanced Subsecond Steady-state Free Precession Sequence During Forced Breathing in Comparison With Spirometry.

PURPOSE: The purpose of this article was to investigate the feasibility of kinematic magnetic resonance imaging (MRI) during forced breathing for the assessment of thoracic and diaphragmatic movement and to compare the results of MRI and spirometry to determine the MRI parameters that are predominantly associated with pulmonary function. MATERIALS AND METHODS: Forty-nine healthy volunteers who underwent kinematic MRI using 2-dimensional balanced subsecond steady-state free precession sequence during forced breathing were included. Several items on the MRI were measured and calculated: these were anteroposterior diameter (APD) of the thorax, APD1, ΔAPD, and cross-sectional area (CSA) of the lung field. The results were compared with the results of spirometry. RESULTS: In the comparison between the spirometry results and the MRI kinematic changes, CSA1, ΔCSA, and CSA1% were most significantly correlated with forced expiratory volume in 1 second (right: P<0.001, r=0.814; left: P<0.001, r=0.759); vital capacity (right: P<0.001, r=0.797; left: P<0.001, r=0.780); and forced expiratory volume% in 1 second (right: P<0.001, r=0.530; left: P<0.001, r=0.518), respectively. The APD1 values in the upper position were significantly larger than those in the middle (right: P<0.001; left: P<0.001) and lower (right: P<0.001; left: P<0.001) positions. The ΔAPD values in the upper position were also significantly larger than those in the middle (right: P<0.001; left: P<0.001) and lower (right: P<0.001; left: P<0.001) positions. CONCLUSION: Kinematic MRI with 2-dimensional balanced subsecond steady-state free precession can be used to assess thoracic and diaphragmatic movement during forced breathing. The dynamic changes in CSA correlated well with the results of spirometry.

Hypovolemic shock complex: does the pancreatic perfusion increase or decrease at contrast-enhanced dynamic CT?

OBJECTIVE: The purpose of this study is to evaluate contrast enhancement effects of the pancreas at dynamic computed tomography (CT) to clarify whether pancreatic perfusion increases or decreases in severe trauma patients with hypovolemic shock. METHODS: A total of 90 patients with (n=30) and without (n=60) blunt trauma and hypovolemic shock who underwent dynamic CT for abdomen was included. The measurement of CT attenuation values of the pancreas in the early phase and the late phase was performed to compare the contrast enhancement effects between patients with and without hypovolemic shock. RESULTS: The mean CT attenuation values of the pancreas in the early phase of dynamic CT in patients with hypovolemic shock [95.4±29.1 Hounsfield units (HU)] were significantly lower (P < .001) than those in non-hypovolemic patients (136.6±17.9 HU), indicating decreased pancreatic perfusion in patients with hypovolemic shock. The mean CT attenuation values of the pancreas in the late phase of dynamic CT in patients with hypovolemic shock (95.9±17.6 HU) were significantly higher (P < .026) than those in non-hypovolemic patients (87.2±9.0 HU), indicating delayed or prolonged pancreatic enhancement in patients with hypovolemic shock. CONCLUSIONS: Decreased pancreatic perfusion in the early phase and delayed pancreatic enhancement in the late phase of contrast-enhanced dynamic CT was a common finding in patients with hypovolemic shock.