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To investigate the current status of interventional radiology (IR) procedures for a type II endoleak (T2EL) in Japan, and to identify the technical aspects that affect treatment results. A retrospective survey was conducted by distributing questionnaires to 25 institutions. The eligibility criteria were endovascular aortic repair (EVAR) performed using commercial stent grafts and IR performed for T2EL between January 2007 and December 2013. Technical success was defined as disappearance of the EL on digital subtraction angiography immediately after embolization, and imaging success was defined as no EL on contrast-enhanced computed tomography within 6 months. Statistical comparisons of the number of involved branches, embolization level, embolic material, and changes in aneurysm size were made between the imaging success and imaging failure groups. The technical and imaging success rates were also compared between the initial therapy and repeat groups. A total of 166 cases were investigated. Initial therapy was performed in 147 cases (88.6 %), with repeat therapy in 19 cases (11.4 %). Transcatheter arterial embolization (TAE) was used most frequently, in 161 cases (97 %), with direct puncture (DP) used in 5 cases (3 %). Both coil embolization for the branches and NBCA embolization for the sac were frequently chosen. The technical success rate was 83.2 % (TAE group), and the imaging success rate was 46.5 % (TAE + DP groups). Branch + sac embolization was performed more frequently in the imaging success group. There was no significant difference in the number of involved branches or embolic material between the imaging success and imaging failure groups. Enlargement of the aneurysm was more frequently seen in the imaging failure group. There were no significant differences in the technical success and imaging success rates between the initial therapy and repeat groups. This is the first report of a multi-institutional questionnaire survey of IR procedures for T2EL after EVAR in Japan that was conducted to determine the current status. Enlargement of aneurysm size after embolization was more frequently seen in the imaging failure group. It is important to embolize both branch and sac to achieve imaging success, regardless of embolic material. Long-term outcomes need to be investigated.

With our methods, the lean body weight exhibited the strongest correlation with aortic and hepatic enhancement; therefore, we suggest it as the best body size index with which to determine the appropriate contrast medium dose at hepatic dynamic CT.

In the field-in-field (FIF) technique in breast tangential radiotherapy, the energy of the subfield is usually the same as the energy of the main field. However, some studies have applied 10–18 MV to subfields in patients with large breasts. We compared two FIF plans in 66 breast cancer patients: in one, the energy of the subfield was the same as that of the main field (the mono energy plan); in the other, it was higher (the dual energy plan). The photon energy of the subfield was 6 MV in the mono energy plan and 10 MV in the dual energy plan. The percentage of the planning target volume (PTV) receiving at least 105, 100, and 95 % of the prescribed dose (V105, V100, and V95, respectively) was calculated, as were the maximum and mean doses delivered to the PTV (Dmax and Dmean, respectively). Clinical target volumes (CTVs) and the thickness of the breast between the chest wall and skin surface at the level of the nipple were measured. V95 % was significantly higher in the dual energy plan than in the mono energy plan in patients with CTVs or breast thickness in the highest quartile. There were no significant differences in the other parameters of the two plans in these patients. These findings demonstrate the usefulness of the dual energy FIF technique in patients with large breasts receiving breast tangential radiotherapy.

The purpose of this study was to assess uterine enhancement rate after abdominal radical trachelectomy (ART) using dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging. Ten patients with early uterine cervical cancer, who were treated by ART, were included in this study. Each patient underwent DCE MR imaging using a 3 T unit to assess uterine enhancement rate at three times (before surgery and 1 and 3 months after surgery). The radiologist calculated mean signal intensities of the anterior and posterior myometrium and also measured the signal intensities of the urine in the bladder on the same image, which was expressed as the myometrium-to-urine signal intensity ratio. In the time–intensity ratio curve, enhancement parameters (peak signal intensity ratio and peak time) of the uterine body were compared across the three MR examinations. The peak signal intensity ratio was 6.96 ± 0.98 on MR examinations before surgery, 6.14 ± 0.81 1 month after surgery, and 6.26 ± 0.63 3 months after surgery (p = 0.069). The peak time was 57.6 ± 3.4 s on MR examinations before surgery, 56.4 ± 4.4 s 1 month after surgery, and 53.2 ± 8.0 s 3 months after surgery (p = 0.304). No significant differences were found in either the peak signal intensity ratio or peak time across the three MR examinations. That no significant decrease of uterine enhancement rate was found after surgery suggests the uterine function and fertility may be preserved after ART.

Background Magnetic resonance imaging (MRI) findings of pilomatricomas have yet to be determined. Purpose To assess the correlation between MRI and pathological findings of pilomatricomas. Material and Methods MR images were obtained on patients with histologically proven pilomatricomas using a 1.5-T MR scanner. The images were retrospectively reviewed for size, signal intensity compared with skeletal muscles, and enhancement patterns. Furthermore, we assessed the presence of a reticular appearance, a ring-like appearance, and peritumoral fat stranding. Results We included 11 consecutive patients with 12 histologically proven pilomatricomas (3 boys/men, 8 girls/women; age range, 4–76 years; mean age, 20 years; median age, 14 years). The tumors were located in the head and neck ( n = 6), upper extremities ( n = 5), and lower extremities ( n = 1). The maximum tumor diameter was in the range of 7–32 mm (mean, 16.5 mm). On T2-weighted (T2W) images, five tumors showed homogeneous hypointensity, whereas six showed reticular hyperintensity and one showed cystic hyperintensity. On fat-suppressed T2W images, nine tumors showed reticular hyperintensity, eight showed ring-like hyperintensity, and five showed peritumoral fat stranding. On fat-suppressed gadolinium-enhanced T1-weighted (T1W) images, one tumor showed no enhancement, whereas three showed reticular enhancement and five showed ring-like enhancement. Histologically, edematous and fibrous stroma was observed in 10 tumors, tumor capsules in 11, and inflammatory cell infiltration of the peritumoral fat tissue in nine. Conclusion MRI features of pilomatricomas included reticular and ring-like hyperintensities on fat-suppressed T2W images and reticular and ring-like enhancement on fat-suppressed gadolinium-enhanced T1W images.

To prospectively determine the feasibility of low-iodine-load and low-tube-voltage computed tomographic (CT) angiographic imaging of the kidney and to evaluate the opacification and image quality compared with moderate-iodine-load and high-iodine-load techniques.Institutional review board approval and written informed consent was obtained. One hundred thirteen consecutive patients randomly underwent three protocols for dual-phase renal CT angiographic imaging: high-iodine-load (600 mg iodine per kilogram of body weight at 120 kVp); moderate-iodine-load (400 mg iodine per kilogram of body weight at 80 kVp); and low-iodine-load (contrast agent injection initially prepared at 400 mg iodine per kilogram of body weight but stopped immediately after bolus-tracking trigger at 80 kVp) scanning. CT numbers of vessels and kidneys were measured. CT numbers and signal-to-noise ratio (SNR) were compared with one-way analysis of variance and posthoc Tukey-Kramer test and depiction of vessels and image noise, with Kruskal-Wallis test and pair-wise Mann-Whitney test with Bonferroni correction.Mean iodine weight administered was significantly reduced in order of low- (16.4 g), moderate- (23.5 g), and high-iodine-load (33.7 g) protocols (P.001). Mean CT numbers of abdominal aorta, renal artery, and renal cortex in first phase were significantly lower with high-iodine-load protocol (308, 274, and 132 HU, respectively) than with moderate- (347, 334, and 156 HU, respectively; P = .001-.006) or low-iodine-load (362, 316, and 161 HU, respectively; P = .001-.003) protocol. Mean CT number of renal vein in second phase was significantly lower with low-iodine-load protocol (223 HU) than with moderate- (299 HU; P.001) or high-iodine-load (258 HU; P = .020). Mean SNR of renal medulla in second phase was significantly lower (P = .019) with moderate-iodine-load protocol (mean SNR, 7.2) than with high-iodine-load protocol (mean SNR, 10.0). No significant difference in image quality grades was found between high-iodine-load (mean grade, 2.6-2.9), moderate-iodine-load (mean grade, 2.6-3.0), and low-iodine-load (mean grade, 2.6-2.9) protocols (P = .018-.31).Combined application of low-iodine-load, bolus tracking with saline flushing, and low-tube-voltage scanning is feasible and resulted in substantial reduction of iodine dose for renal CT angiographic imaging without compromising image quality.

The objective of our study was to compare diffusion kurtosis imaging (DKI) with conventional diffusion-weighted imaging (DWI) for assessing the response to treatment in hypervascular hepatocellular carcinoma (HCC).Sixty-two consecutive patients with treated or untreated hypervascular HCC underwent MRI of the liver including DKI (b values of 0, 100, 500, 1000, 1500, and 2000 s/mm(2)). The mean kurtosis (MK) and apparent diffusion coefficient (ADC) values of the hepatic parenchyma and of the HCCs were computed. The detectability of viable HCC based on MK and ADC values was compared. We also assessed the correlation between Child-Pugh grades and MK or ADC values.For a total of 112 HCC nodules (viable, n = 63; nonviable, n = 49), the MK value was significantly higher for the viable group (mean ± SD, 0.81 ± 0.11) than for the non-viable group (0.57 ± 0.11) (p0.001). The mean ADC value was significantly lower for the viable group (1.44 ± 0.42 × 10(-3) mm(2)/s) than for the nonviable group (1.94 ± 0.52 × 10(-3) mm(2)/s) (p0.001). The sensitivity, specificity, and AUC of the ROC curve for the assessment of HCC viability were greater (p0.001) using MK (85.7%, 98.0%, and 0.95, respectively; cutoff value = 0.710) than using ADC (79.6%, 68.3%, and 0.77, respectively; cutoff value = 1.535 × 10(-3) mm(2)/s). Although the ADC of hepatic parenchyma was lower in patients with Child-Pugh grade B or C disease than in those with grade A disease (p = 0.02), no significant difference in MK (p = 0.45) was found among the Child-Pugh grades.DKI can be a new option for the assessment of posttherapeutic response in HCC.

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

Author(s): Nozawa, Asae; Rivandi, Ali Hosseini; Kanematsu, Masayuki; Hoshi, Hiroaki; Piccioni, David; Kesari, Santosh; Hoh, Carl K | Abstract: BackgroundStandardized uptake values (SUVs) of fluorine-18 fluorodeoxyglucose PET ((18)F-FDG PET) are used widely to differentiate residual or recurrent high-grade gliomas from post-treatment changes in patients with brain tumors. The aim of this study is to assess the accuracy of SUV corrected by blood glucose level (SUV(gluc)) compared with various quantitative methods in this role.Materials and methodsIn 55 patients with dynamic F-FDG PET scans, there were 97 glioma lesions: glioblastoma (n=60), grade III gliomas (n=22), grade III or IV gliomas (n=6), grade I/II (n=7), and prebiopsy lesions (n=2). The final actual diagnosis was made on the basis of pathology (n=33) and clinical outcome (n=64). Dynamic F-FDG PET scans were processed to generate parametric images of SUV(gluc), SUV(max), and glucose metabolic rate (GMR). Lesion to cerebellum ratios (SUV(Rc)) and contralateral white matter ratios (SUV(Rw)) were also measured. The SUV(gluc) was calculated as SUV(max)×blood glucose level/100.ResultsUsing the thresholds of SUV(max)g4.6, SUV(Rc)g0.9, SUV(Rw)g1.8, SUV(gluc)g4.3, and GMRg12.2 μmol/min/100 g to represent positivity for viable tumors, the accuracies were the same for the SUV(gluc) and SUV(Rw) (80%) and were higher than the conventional SUV(max) (72%). The area under the receiver operating characteristic curve for the SUV(gluc) (0.8933) was better than that for the SUV(max) (0.8266) (Pl0.01) and was similar to those of the GMR (0.8622), SUV(Rc) (0.8606), and SUV(Rw) (0.8981).ConclusionThese results suggest that SUV(gluc) may aid in the differentiation of residual or recurrent high-grade tumor from post-treatment changes in patients with abnormal blood glucose levels. The simplicity of the SUV(gluc) avoids the complexity of kinetic analysis or the requirement of a reference tissue.

To quantitatively assess magnetic resonance (MR) imaging findings that help predict early post-therapeutic response in fibroids following uterine artery embolization (UAE).Fifteen patients with a total of 52 fibroids underwent UAE. The signal intensity ratio (SIR) on T1-, T2-, diffusion weighted and gadolinium-enhanced images was calculated by dividing the mean signal intensity of fibroids by that of the abdominal rectus muscle. Fibroids were divided into the two groups: affected (post-UAE volume reduction ratemedian of all fibroids) and unaffected (median rate). The SIRs were compared between the two groups. ROC analysis was used to evaluate the predictive performance for differentiating the affected from unaffected lesions.The SIRs of the affected group were significantly lower on T1-weighted images (0.85±0.1 vs 0.95±0.2) (P=0.0001), but higher on T2-weighted (1.30±0.6 vs 1.12±0.9) (P=0.026) and gadolinium-enhanced images (1.51±0.2 vs 1.20±0.4) (P=0.0002) than those of the unaffected group. There was no significant difference in ADC values between the two groups (P=0.510). The sensitivity, specificity, and area under the ROC curve (AUC) in the prediction of the affected lesions were 92%, 50%, and 0.712 with SIR on T1-weighted images, and 85%, 62%, and 0.731 with SIR on gadolinium-enhanced images, respectively.The SIRs on T1-weighted images and gadolinium-enhanced images were useful for the prediction of the changes in size of fibroids responding to UAE.

We presented a 27-year-old male diagnosed with intraosseous schwannoma of the ilium. Computed tomographic images revealed a well-demarcated, lobulated, expansile, osteolytic lesion in the right supraacetabular region of the ilium. In addition, an intratumoral punctate calcification and a sclerotic rim were observed. T2-weighted magnetic resonance (MR) images demonstrated a heterogeneously hyperintense lesion with a hypointense rim. Major parts of the lesion, excluding some central areas, were enhanced on gadolinium-enhanced MR images. Pathological examination revealed an intraosseous schwannoma. Our findings indicate that intraosseous schwannoma should be considered when images demonstrate a well-demarcated, lobulated, expansile, osteolytic lesion with a sclerotic rim.

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.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.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.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.

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 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.

To determine the optimal iodine mass (IM) to achieve a 50-HU increase in hepatic attenuation for the detection of liver metastasis based on total body weight (TBW) or body surface area (BSA) at 80-kVp computed tomography (CT) imaging of the liver. One-hundred and fifty patients who underwent contrast-enhanced CT at 80-kVp were randomised into three groups: 0.5 gI/kg, 0.4 gI/kg and 0.3 gI/kg. Portal venous phase images were evaluated for hepatic parenchymal enhancement (∆HU) and visualisation of liver metastasis. Iodine mass per BSA (gI/m2) calculated in individual patients were evaluated. Mean ∆HU for the 0.5 gI/kg group (84.2 HU) was higher than in the 0.4 gI/kg (66.1 HU) and 0.3 gI/kg (53.7 HU) groups (P

A 69-year-old postmenopausal female with a spontaneously occurring uterine pyomyoma was described with emphasis on the MR imaging findings. On unenhanced T1- and T2-weighted MR images, a huge mottled mass suspected to contain blood products, necrotic tissue, or purulent or viscous fluid was demonstrated within anterior myometrial wall of uterine body. The mass was surrounded by a peripheral rim that was hyperintense on T1-weighted images and hypointense on T2-weighted images. On gadolinium-enhanced MR images, most of the mass was unenhanced, but the peripheral rim was equally enhanced with the surrounding myometrium. Pathological examination revealed an intramural uterine pyomyoma surrounded by fibrous capsules with abundant lymphocytes and neutrophils. Our findings indicate that pyomyoma should be considered when MR images demonstrate a myometrial cystic lesion accompanied by a peripheral rim.

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.

Palatal tumors commonly arise from the minor salivary glands, and benign tumors account for approximately half of all minor salivary gland tumors. Minor salivary gland tumors have an affinity for the posterior hard palate and soft palate and virtually never arise in the midline, probably because of the distribution of palatal salivary glands. The majority of benign salivary gland tumors of the palate are pleomorphic adenomas, while the most common malignant salivary gland tumor is adenoid cystic carcinoma, followed by mucoepidermoid carcinoma, adenocarcinoma, and polymorphous low-grade adenocarcinoma. Epithelial tumors frequently arise from the soft palate. The majority of benign epithelial tumors of the palate are papillomas, while most malignant epithelial tumors are squamous cell carcinomas. Various types of mesenchymal tumors, including fibromas, lipomas, schwannomas, neurofibromas, hemangiomas, and lymphangiomas, also involve the palate. This article describes the CT and MR findings of benign and malignant palatal tumors.

The shapes of the inner organs are important information for medical image analysis. Statistical shape modeling provides a way of quantifying and measuring shape variations of the inner organs in different patients. In this study, we developed a universal scheme that can be used for building the statistical shape models for different inner organs efficiently. This scheme combines the traditional point distribution modeling with a group-wise optimization method based on a measure called minimum description length to provide a practical means for 3D organ shape modeling. In experiments, the proposed scheme was applied to the building of five statistical shape models for hearts, livers, spleens, and right and left kidneys by use of 50 cases of 3D torso CT images. The performance of these models was evaluated by three measures: model compactness, model generalization, and model specificity. The experimental results showed that the constructed shape models have good "compactness" and satisfied the "generalization" performance for different organ shape representations; however, the "specificity" of these models should be improved in the future.