Visualization of incidentally imaged pituitary gland on three-dimensional arterial spin labeling of the brain.

OBJECTIVE: To evaluate the visualization of incidentally imaged normal pituitary gland on three-dimensional (3D) pseudo continuous arterial spin labeling (PCASL) perfusion imaging of the brain. METHODS: Ninety-three patients with a normal pituitary gland who underwent 3D PCASL for suspected brain diseases were retrospectively included. Visualization of the pituitary gland on PCASL cerebral blood flow (CBF) maps was assessed independently by two observers using a three-point grading system: Grade 1, pituitary CBF ≤ CBF of the cerebral white matter (WM); Grade 2, CBF of WM < pituitary CBF ≤ CBF of the cortical gray matter (GM); and Grade 3, CBF of GM < pituitary CBF. The interobserver agreement of visual grading was determined using weighted κ statistic. The associations of visual grades with age, sex, and pituitary volume were assessed using multivariate logistic regression. Pituitary glands were divided equally into three groups (small, medium, and large) according to their volume for categorization. RESULTS: The interobserver agreement for visual rating was excellent (weighted κ = 0.823). Of the 93 cases, Grades 1, 2, and 3 included 17 (18.3%), 41 (44.1%), and 35 cases (37.6%), respectively. Medium and large pituitary volume were significantly associated with Grade 3 visualization (p = 0.0153, OR = 4.8323; 95% CI: 1.3525, 17.2649 and p = 0.0009; OR = 9.0299; 95% CI: 2.4663, 33.0614, respectively), whereas there was no significant association for age or sex. CONCLUSION: The normal pituitary gland is often visualized with higher CBF than cortical GM on 3D PCASL, especially in individuals with larger pituitary volume. ADVANCES IN KNOWLEDGE: Appearance of the normal pituitary gland on 3D PCASL has been documented for the first time.

Quantitative pharmacokinetic analysis of high-temporal-resolution dynamic contrast-enhanced MRI to differentiate the normal-appearing pituitary gland from pituitary macroadenoma.

PURPOSE: To evaluate the usefulness of high-temporal-resolution dynamic contrast-enhanced (DCE) MRI and quantitative pharmacokinetic analysis to differentiate the normal-appearing pituitary gland from a pituitary macroadenoma. MATERIALS AND METHODS: Twenty-seven patients with macroadenomas underwent preoperative DCE-MRI with a temporal resolution of 5 s using compressed sensing to obtain pharmacokinetic parameters. Two independent observers localized the normal-appearing pituitary gland on post-contrast T1-weighted images before and after referring to the corresponding Ktrans maps. Agreements between the localizations and intraoperative findings were evaluated using the kappa statistics. The Mann-Whitney U test was used to compare the pharmacokinetic parameters of the normal-appearing pituitary gland and adenoma. RESULTS: For both observers, the agreement between the MRI-based localization and the intraoperative findings increased after referring to the Ktrans maps (observer 1, 0.930-1; observer 2, 0.636-0.855). The normal-appearing pituitary gland had significantly higher Ktrans [/min] (1.50 ± 0.80 vs 0.58 ± 0.49, P < 0.0001), kep [/min] (3.19 ± 1.29 vs 2.15 ± 1.18, P = 0.0049), and ve (0.43 ± 0.15 vs 0.25 ± 0.17, P = 0.0003) than adenoma. CONCLUSION: High-temporal-resolution DCE-MRI and quantitative pharmacokinetic analysis help accurately localize the normal-appearing pituitary gland in patients with macroadenomas. The normal-appearing pituitary gland was characterized by higher Ktrans, kep, and ve than macroadenoma. Dynamic contrast-enhanced MRI with high-temporal-resolution using compressed sensing was used for quantitative pharmacokinetic analysis of pituitary macroadenomas. An observer study, the use of Ktrans maps improved accuracy in localizing the normal-appearing pituitary gland. As compared to an adenoma, the normal-appearing pituitary gland had significantly higher Ktrans, kep, and ve values.

Histological Grade of Meningioma: Prediction by Intravoxel Incoherent Motion Histogram Parameters.

RATIONALE AND OBJECTIVES: To evaluate the usefulness of intravoxel incoherent motion (IVIM) histogram analysis for differentiating low-grade meningiomas (LGMs) and high-grade meningiomas (HGMs). MATERIALS AND METHODS: Fifty-nine patients with pathologically confirmed meningiomas (45 LGMs and 14 HGMs) underwent IVIM MR imaging. Maps of IVIM parameters (perfusion fraction, f; true diffusion coefficient, D; and pseudo diffusion coefficient, D*), as well as of the apparent diffusion coefficient (ADC), were generated. Histogram analysis was performed using parametric values from all voxels in regions-of-interest manually drawn to encompass the whole tumor. The histogram results of ADC and IVIM parameters were compared using the Mann-Whitney U test. Area under the receiver operating characteristic curve (AUC) values were generated to evaluate how well each parameter could differentiate LGMs from HGMs. Spearman's rank correlation coefficients were used to evaluate correlations between histogram parameters and Ki-67 expression. RESULTS: Compared to LGM, HGM showed significantly higher standard deviation (SD), variance, and coefficient of variation (CV) of ADC (p< 0.006-0.028; AUC, 0.693-0.748), D (p< 0.004-0.032; AUC, 0.670-0.752), and significantly higher CV of f (p< 0.005-0.024; AUC = 0.737). Means and percentiles of ADC and IVIM parameters did not differ significantly between LGM and HGM. Significant positive correlations were identified between Ki-67 and histogram parameters of ADC (SD, variance, kurtosis, skewness, and CV) and D (SD, variance, kurtosis, and CV), whereas no significant correlation with Ki-67 was shown for mean or percentiles of ADC and IVIM parameters. CONCLUSION: Heterogeneity histogram parameters of ADC, D, and f may be useful for differentiating LGMs from HGMs.

Assessment of microvessel perfusion of pituitary adenomas: a feasibility study using turbo spin-echo-based intravoxel incoherent motion imaging.

OBJECTIVES: To evaluate the feasibility of assessment of microvessel perfusion of pituitary adenomas with intravoxel incoherent motion (IVIM) imaging using single-shot turbo spin-echo-based diffusion-weighted imaging (SS-TSE-DWI). METHODS: We examined 51 consecutive patients with pituitary adenomas (35 non-functioning and 16 functioning) and 32 patients with normal pituitary glands using SS-TSE-DWI IVIM. The diffusion coefficient (D), the perfusion fraction (f), and the pseudo-diffusion coefficient (D*) were calculated pixel-by-pixel for each adenoma and normal pituitary gland. We also obtained the pathological microvessel area (MVA) of each adenoma. The IVIM parameters in adenomas were compared with those in normal pituitary glands using the Mann-Whitney U test. The correlation between the MVA and IVIM f of adenomas was analyzed using Spearman's rank correlation coefficient. RESULTS: The mean D (× 10-3 mm2/s) in adenomas was 0.723 ± 0.253, which was significantly lower than that in normal pituitary glands (0.862 ± 0.128; p < 0.0001). The mean f (%) in adenomas was 10.74 ± 4.51, which was significantly lower than that in normal pituitary glands (13.26 ± 4.32, p = 0.0251). No significant difference was found in the mean D*. We found a significant positive correlation between MVA and f in non-functioning adenomas (ρ = 0.634, p < 0.0001) as well as in all adenomas (ρ = 0.451, p = 0.0009). CONCLUSIONS: Assessment of microvessel perfusion of pituitary adenomas based on SS-TSE-DWI IVIM is feasible. Compared to normal pituitary glands, pituitary adenomas were characterized by lower D and f. KEY POINTS: • Assessment of microvessel perfusion of pituitary adenomas based on SS-TSE-IVIM is feasible. • SS-TSE-IVIM helps with evaluation of the vascularity of pituitary lesions. • Pituitary adenomas were characterized by lower D and f than normal pituitary glands.

Celecoxib as a Potential Treatment for Intractable Lymphatic Malformation.

Lymphatic malformation (LM) is a congenital disorder resulting from an abnormal development of lymphatic vessels. LM may result in problems of cosmesis and functional impairment, including airway compression. An 11-year-old girl was referred to our department with increasing dysphagia caused by a large left cervical LM with a long history of treatment. Because of the LM location, surgical resection was not an option, and various therapies, including use of picibanil, had proven ineffective. Celecoxib treatment (100 mg/day) was initiated for local pain management. Softening of the lesion was observed 2 weeks after treatment initiation, and the dose was increased to 200 mg/day with additional shrinking of the LM over the next 2 weeks. With parental consent, celecoxib was continued, with a 65% reduction in volume achieved at 6 months. The patient discontinued treatment at 12 months, and the LM volume increased. Control over the LM was achieved with resumption of celecoxib treatment. After 2 years of treatment, the LM persists, but the size of the malformation is significantly smaller. No adverse effects of celecoxib treatment were observed. The anti-cyclooxygenase-2 effect of celecoxib prevented lymphatic vessel growth through an inhibition of cyclooxygenase-2 activity in the conversion of prostaglandin to prostaglandin E2. In conclusion, celecoxib may be a promising therapeutic agent for LM management.

Amide proton transfer imaging of tumors: theory, clinical applications, pitfalls, and future directions.

Amide proton transfer (APT) imaging is an emerging molecular magnetic resonance imaging technique based on chemical exchange saturation transfer (CEST). APT imaging has shown promise in oncologic imaging, especially in the imaging of brain tumors. This review article illustrates the theory of CEST/APT imaging and describes the clinical utility, pitfalls, and potential for future development of APT imaging.

Histogram analysis of amide proton transfer-weighted imaging: comparison of glioblastoma and solitary brain metastasis in enhancing tumors and peritumoral regions.

OBJECTIVES: Differentiation of glioblastomas (GBMs) and solitary brain metastases (SBMs) is an important clinical problem. The aim of this study was to determine whether amide proton transfer-weighted (APTW) imaging is useful for distinguishing GBMs from SBMs. METHODS: We examined 31 patients with GBM and 17 with SBM. For each tumor, enhancing areas (EAs) and surrounding non-enhancing areas with T2-prolongation (peritumoral high signal intensity areas, PHAs) were manually segmented using fusion images of the post-contrast T1-weighted and T2-weighted images. The mean amide proton transfer signal intensities (APTSIs) were compared among the EAs, PHAs, and contralateral normal appearing white matter (NAWM) within each tumor type. Furthermore, we analyzed APTSI histograms to compare the EAs and PHAs of GBMs and SBMs. RESULTS: In GBMs, the mean APTSI in EAs (2.92 ± 0.74%) was the highest, followed by that in PHAs (1.64 ± 0.83%, p < 0.001) and NAWM (0.43 ± 0.83%, p < 0.001). In SBMs, the mean APTSI in EAs (1.85 ± 0.99%) and PHAs (1.42 ± 0.45%) were significantly higher than that in NAWM (0.42 ± 0.30%, p < 0.001), whereas no significant difference was found between EAs and PHAs. The mean and 10th, 25th, 50th, 75th, and 90th percentiles for APT in EAs of GBMs were significantly higher than those of SBMs. However, no significant difference was found between GBMs and SBMs in any histogram parameters for PHA. CONCLUSIONS: APTSI in EAs, but not PHAs, is useful for differentiation between GBMs and SBMs. KEY POINTS: • Amide proton transfer-weighted imaging and histogram analysis in the enhancing tumor can provide useful information for differentiation between glioblastomas and solitary brain metastasis. • Amide proton transfer signal intensity histogram parameters from peritumoral areas showed no significant difference between glioblastomas and solitary brain metastasis. • Vasogenic edema alone can substantially increase amide proton transfer signal intensity which may mimic tumor invasion.

Whole-tumor apparent diffusion coefficient (ADC) histogram analysis to differentiate benign peripheral neurogenic tumors from soft tissue sarcomas.

BACKGROUND: Apparent diffusion coefficient (ADC) histogram analyses have been used to differentiate tumor grades and predict therapeutic responses in various anatomic sites with moderate success. PURPOSE: To determine the ability of diffusion-weighted imaging (DWI) with a whole-tumor ADC histogram analysis to differentiate benign peripheral neurogenic tumors (BPNTs) from soft tissue sarcomas (STSs). STUDY TYPE: Retrospective study, single institution. SUBJECTS: In all, 25 BPNTs and 31 STSs. FIELD STRENGTH/SEQUENCE: Two-b value DWI (b-values = 0, 1000s/mm2 ) was at 3.0T. ASSESSMENT: The histogram parameters of whole-tumor for ADC were calculated by two radiologists and compared between BPNTs and STSs. STATISTICAL TESTS: Nonparametric tests were performed for comparisons between BPNTs and STSs. P < 0.05 was considered statistically significant. The ability of each parameter to differentiate STSs from BPNTs was evaluated using area under the curve (AUC) values derived from a receiver operating characteristic curve analysis. RESULTS: The mean ADC and all percentile parameters were significantly lower in STSs than in BPNTs (P < 0.001-0.009), with AUCs of 0.703-0.773. However, the coefficient of variation (P = 0.020 and AUC = 0.682) and skewness (P = 0.012 and AUC = 0.697) were significantly higher in STSs than in BPNTs. Kurtosis (P = 0.295) and entropy (P = 0.604) did not differ significantly between BPNTs and STSs. DATA CONCLUSION: Whole-tumor ADC histogram parameters except kurtosis and entropy differed significantly between BPNTs and STSs. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Computed tomography and magnetic resonance imaging features of lipid-rich neuroendocrine tumors of the pancreas.

AIM: To clarify the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of lipid-rich pancreatic neuroendocrine tumors (PanNETs). METHODS: Enhanced CT and MRI performed before pancreatectomy in 29 patients with 34 histologically-confirmed PanNETs was retrospectively reviewed. Tumor attenuation on CT and signal intensities on conventional (T1- and T2-weighted) and chemical shift MRI were qualitatively analyzed and compared alongside adipose differentiation-related protein (ADRP) immunostaining (ADRP-positive: lipid-rich; ADRP-negative: non-lipid-rich) results using Fisher's exact test or the Mann-Whitney U test. Signal intensity index on chemical shift MRI was quantitatively assessed. RESULTS: There were 15 lipid-rich PanNETs (44.1%) in 12 patients (41.4%). Tumor attenuation during the early, portal venous, and delayed phases of enhanced CT (P = 0.888, 0.443, and 0.359, respectively) and signal intensities on conventional MRI (P = 0.698 and 0.798, respectively) were not significantly different between lipid-rich and non-lipid-rich PanNETs. Four of the 15 lipid-rich PanNETs exhibited high signal intensity on subtraction chemical shift MRI, and the association of high signal intensity on subtraction imaging with lipid-rich PanNETs was significant (4 of 15 lipid-rich PanNETs, 26.73%, vs 0 of 19 non-lipid-rich PanNETs, 0%, P = 0.029). Lipid-rich PanNETs showed a significantly higher signal intensity index than non-lipid-rich PanNETs (0.6% ± 14.1% vs -10.4% ± 14.4%, P = 0.004). Eight of 15 lipid-rich PanNETs, vs 0 of 19 non-lipid-rich PanNETs, had positive signal intensity index values in concordance with lipid contents. CONCLUSION: CT contrast enhancement and conventional MR signal intensities are similar in lipid-rich and non-lipid-rich PanNETs. Chemical shift MRI can demonstrate cytoplasmic lipids in PanNETs.

Diagnostic performances of FDG-PET/CT and diffusion-weighted imaging indices for differentiating benign pheochromocytoma from other benign adrenal tumors.

PURPOSE: The purpose of this study is to compare diagnostic performances of (18)F-fluorodeoxyglucose (FDG) visual score, maximum standardized uptake value (SUVmax), ratio of adrenal SUVmax to liver SUVmax (A/L SUVmax), apparent diffusion coefficient (ADC) from diffusion-weighted imaging, and SUVmax/ADC ratio to differentiate adrenal pheochromocytoma from other benign tumors. METHODS: Eleven pheochromocytomas and 22 other benign tumors in 30 patients were included. FDG-based indices, ADC, and SUVmax/ADC ratio were compared between groups using the Mann-Whitney U test, and sensitivity, specificity, accuracy, and area under the curve (AUC) for diagnosing pheochromocytoma by receiver operating characteristic analyses. The correlation between SUVmax and ADC was analyzed using the Spearman's rank test. RESULTS: Pheochromocytoma showed significantly higher visual score (2.8 ± 0.4 vs. 1.3 ± 0.9), SUVmax (11.0 ± 8.9 vs. 3.2 ± 1.4), A/L SUVmax ratio (3.96 ± 3.48 vs. 0.96 ± 0.51), and SUVmax/ADC ratio (10.6 ± 8.09 vs. 2.28 ± 0.98) (each P < 0.001) and significantly lower ADC (1.08 ± 0.23 × 10(-3) mm(2)/s vs. 1.43 ± 0.29 × 10(-3) mm(2)/s, P = 0.003) than other benign tumors. Sensitivity, specificity, and accuracy for diagnosing pheochromocytoma were 100, 73, and 82% for visual score, 100, 86, and 91% for both SUVmax and A/L SUVmax ratio, and 64, 100, and 88% for ADC and 82, 95, and 91% for SUVmax/ADC ratio. No significant differences in AUC were found between FDG-based indices, ADC, and SUVmax/ADC ratio. A significant negative correlation was noted between SUVmax and ADC (ρ = -0.36, P = 0.039). CONCLUSION: FDG-based indices and ADC appear comparably useful for differentiating pheochromocytoma from other benign adrenal tumors.

Quantitative evaluation of liver function with T1 relaxation time index on Gd-EOB-DTPA-enhanced MRI: comparison with signal intensity-based indices.

PURPOSE: To evaluate whether the reduction rate of T1 relaxation time of the liver (T1 relaxation time index) before and 20 minutes after gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) injection has the potential to serve as an magnetic resonance imaging (MRI)-based liver function test in comparison with signal intensity-based indices. MATERIALS AND METHODS: Ninety-nine patients with suspected liver lesions underwent Gd-EOB-DTPA-enhanced MRI. T1 maps using 3D T1-weighted gradient-echo volumetric interpolated examination with two different flip angles were also performed before and 20 minutes after Gd-EOB-DTPA administration. T1 relaxation time index was compared with four signal intensity-based indices in terms of the ability to discriminate Child-Pugh A (CPA) and Child-Pugh B (CPB) from normal liver function (NLF), and in terms of its correlation with indocyanine green (ICG) clearance. RESULTS: Twenty-four patients were classified as NLF, 64 patients were classified as CPA, and 11 were classified as CPB group. The T1 relaxation time index was significantly lower for CPA (0.62 ± 0.08 vs. 0.68 ± 0.07, P = 0.021) and CPB (0.55 ± 0.15 vs. 0.68 ± 0.07, P < 0.001) than for NLF. All signal intensity-based indices showed significant differences only when comparing NLF and CPB. The correlation coefficient with ICG clearance was the highest for T1 relaxation time index (r = -0.605, P < 0.001). CONCLUSION: The T1 relaxation time index has the potential to serve as an MRI-based liver function test, and is most strongly correlated with ICG clearance among the Gd-EOB-DTPA MRI-based indices investigated.

Contrast-enhanced CT and diffusion-weighted MR imaging: performance as a prognostic factor in patients with pancreatic ductal adenocarcinoma.

OBJECTIVE: To determine whether contrast enhancement of CT and apparent diffusion coefficient on diffusion-weighted MR imaging are important parameters that can predict outcomes for patients with pancreatic ductal adenocarcinoma. MATERIALS AND METHODS: Ninety-two patients with histologically confirmed pancreatic ductal adenocarcinoma who underwent quadriphasic CT (including unenhanced, pancreatic parenchymal, portal venous and delayed phases) and fat-suppressed single-shot echo-planar diffusion-weighted MR imaging at 3.0 T were retrospectively analyzed to investigate prognostic factors. Overall survival curves were drawn using the Kaplan-Meier method. Effects on survival of variables including age, sex, tumor location, tumor size, TNM stage, carbohydrate antigen 19-9, carcinoembryonic antigen, treatment, tumor contrast enhancement and apparent diffusion coefficient values were analyzed in univariate analysis using the log-rank test. Variables were analyzed in multivariate analyses using the Cox proportional hazards regression model. RESULTS: Median survival for the entire patient population was 18.2 months. Higher contrast enhancement during all phases was associated with significantly longer overall survival (P<0.001 for all phases). The difference in overall survival between groups divided by median apparent diffusion coefficient value was not significant (P=0.672). TNM stage (P=0.026) and tumor contrast enhancement on CT (P=0.027) were significantly related to survival in multivariate analysis. CONCLUSIONS: Poor enhancement of pancreatic adenocarcinomas on enhanced CT is associated with reduced patient survival.

Efficacy of liver parenchymal enhancement and liver volume to standard liver volume ratio on Gd-EOB-DTPA-enhanced MRI for estimation of liver function.

OBJECTIVE: We aimed to develop and assess the efficacy of a liver function index that combines liver enhancement and liver volume to standard liver volume (LV/SLV) ratio on gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MRI. METHODS: In all, 111 patients underwent a Gd-EOB-DTPA-enhanced MRI, including T1 mapping, before and 20 min after Gd-EOB-DTPA administration. We calculated the following Gd-EOB-DTPA-enhanced MRI-based liver function indices: relative enhancement of the liver, corrected enhancement of the liver-to-spleen ratio, LSC_N20, increase rate of the liver-to-muscle ratio, reduction rate of T1 relaxation time of the liver, ΔR1 of the liver and K Hep; the indices were multiplied by the LV/SLV ratio. We calculated the correlations between an indocyanine green (ICG) clearance and the Gd-EOB-DTPA-enhanced MRI-based liver function indices multiplied by the LV/SLV ratio, by using Pearson correlation analysis. RESULTS: There were significant correlations between all Gd-EOB-DTPA-enhanced MRI-based liver function indices and ICG clearance (r = -0.354 to -0.574, P < 0.001). All Gd-EOB-DTPA-enhanced MRI-based liver function indices multiplied by the LV/SLV ratio (r = -0.394 to -0.700, P < 0.001) were more strongly correlated with the ICG clearance than those without multiplication by the LV/SLV ratio. CONCLUSIONS: Gd-EOB-DTPA-enhanced MRI-based liver function indices that combine liver enhancement and the LV/SLV ratio may more reliably estimate liver function. KEY POINTS: • Gd-EOB-DTPA-enhanced MRI is useful for assessing liver function. • Liver enhancement on Gd-EOB-DTPA-enhanced MRI correlates with indocyanine green (ICG) clearance. • Liver volume to standard liver volume (LV/SLV) ratio correlates with ICG clearance. • Liver enhancement and LV/SLV ratio help to estimate liver function.

Muscle mass and composition of the hip, thigh and abdominal muscles in women with and without hip osteoarthritis.

The objective of this study was to compare muscle mass and composition between individuals with and without hip osteoarthritis. Twenty-four women with hip osteoarthritis (OA group) and 16 healthy women (healthy group) participated in this study. Muscle thickness (MT) and echo intensity (EI) were measured as indices of muscle mass and composition, respectively, using ultrasound imaging. Seven muscles were examined: gluteus maximus, gluteus medius, quadriceps femoris, rectus abdominis, external oblique, internal oblique and transversus abdominis. MT of only quadriceps femoris in the OA group was significantly thinner than that in the healthy group. EIs of gluteus medius, quadriceps femoris and rectus abdominis were significantly higher in the OA group than those in the healthy group. Thus, actual contractile tissue of gluteus medius and rectus abdominis substantially decreased, although muscle mass was similar, whereas both quantitative and qualitative changes occurred in quadriceps femoris in patients with hip OA.

Distinguishing adrenal adenomas from nonadenomas: combined use of diagnostic parameters of unenhanced and short 5-minute dynamic enhanced CT protocol.

PURPOSE: To retrospectively examine the diagnostic values of individual parameters obtained from unenhanced and 35-second and 5-minute contrast material-enhanced (enhanced) computed tomography (CT) in distinguishing adenomas, particularly lipid-poor adenomas, from nonadenomas and to determine the best diagnostic method by using these parameters. MATERIALS AND METHODS: This retrospective study had institutional review board approval; the need for informed consent was waived. The study population consisted of 61 patients (20 men and 41 women; mean age, 58 years) with 68 adrenal masses (53 adenomas and 15 nonadenomas). In each patient, unenhanced CT was followed by 35-second and 5-minute enhanced CT. Adenomas were classified as 30 lipid-rich (10 HU) adenomas by using unenhanced attenuation. The diagnostic parameters were tumor size, unenhanced attenuation, 35-second and 5-minute enhanced attenuation, wash-in and washout attenuation, percentage enhancement washout ratio (PEW), and relative PEW (RPEW). The sensitivity, specificity, and accuracy for diagnosing adenomas were calculated by using a threshold level of each parameter determined by the least sum of false-positive and false-negative cases and a combination of the threshold levels with 100% specificity. RESULTS: The best results were obtained by using a combination of the threshold levels with 100% (15 of 15) specificity (presence of at least one of the following criteria for diagnosing adenomas: unenhanced attenuation of or=45%, and RPEW of >or=31%). Sensitivity was 94% (50 of 53) or 87% (20 of 23) and accuracy was 96% (65 of 68) or 92% (35 of 38) for diagnosing total adrenal adenomas or lipid-poor adenomas, respectively. CONCLUSION: Combining the diagnostic parameters of the CT protocol can yield diagnostic results comparable to those with previously reported longer dynamic enhanced CT protocols.

Pancreatic adenocarcinoma: analysis of the effect of various concentrations of contrast material.

PURPOSE: The aim of this study was to compare the efficacy of two contrast materials with moderate and high iodine concentrations for the depiction of pancreatic adenocarcinoma. MATERIALS AND METHODS: A series of 107 patients with histologically proven pancreatic adenocarcinoma underwent helical computed tomography. A fixed dose of 100 ml of iopamidol 300 (mg I/ml) was administered to 50 patients (group A) and iopamidol 370 (mg I/ml) to 57 patients (group B) at the same injection rate (3 ml/s). Unenhanced helical scans and contrast-enhanced scans for three phases (30, 70, and 300 s after starting the infusion of contrast material) were obtained. We evaluated enhancement of the aorta, portal vein, hepatic parenchyma, pancreatic parenchyma, and pancreatic adenocarcinoma during each phase. RESULTS: During all phases, both aortic and pancreatic enhancement were significantly greater in group B than in group A (P<0.01). Enhancement of the portal vein and hepatic parenchyma was significantly greater at 70 and 300 s in group B than in group A (both P<0.01). Tumor-to-pancreas contrast was significantly greater in group B than in group A at both 30 s (P<0.01) and 70 s (P<0.05). CONCLUSION: Administration of contrast material with a high iodine concentration is more effective for depicting pancreatic adenocarcinomas.