加藤 扶美

There have been no reports regarding imaging-documented bronchospasm in patients with amniotic fluid embolism (AFE). In a woman with scheduled cesarean section for placenta previa, transient bronchospasm and pulmonary hypertension were documented explaining a sudden drop in SpO2. Mild AFE was the most likely diagnosis in this patient.

We report a case of breast cancer detected as an incidental finding on 99mTc-MIBI scintigraphy. 99mTc-MIBI scintigraphy is usually used to evaluate cardiac perfusion or to detect ectopic parathyroid adenomas; however, it is also known to sensitively detect breast cancer. Accordingly, a few reports have described the incidental detection of breast cancer by 99mTc-MIBI scintigraphy performed to detect parathyroid adenoma. Our present case underscores the importance of attending to any incidental findings when searching for parathyroid adenomas using 99mTc-MIBI scintigraphy.

PURPOSE: This study aimed to evaluate whether histogram analysis of the apparent diffusion coefficient (ADC) of a solid tumor component could distinguish borderline ovarian tumors from ovarian carcinoma. MATERIALS AND METHODS: Sixteen pathologically proven borderline tumors and 21 carcinomas were retrospectively examined. Magnetic resonance (1.5-T) image data sets were coregistered, and the solid components of each tumor were semiautomatically segmented. ADC histograms of the solid components were extracted; modes, minimums, means, and 10th, 25th, 50th, 75th, and 90th percentiles of the histograms were compared between the two tumor types, and receiver-operating characteristic (ROC) analysis was performed. RESULTS: The mode, minimum, mean, 10th, 25th, 50th, and 75th percentile ADC values of solid components of borderline tumors were significantly larger than those of carcinomas. Among these, the 10th percentile values had the lowest p value (p = 0.0003). At ROC analysis, the area under the curve (AUC) in the 10th percentile was the greatest (0.854), and the best cutoff value in the 10th percentile provided the highest specificity (93.8 %). CONCLUSIONS: ADC histograms of solid tumor components facilitated the distinction between borderline ovarian tumors and carcinoma. The 10th percentile ADC values had the best diagnostic performance.

BACKGROUND: To clarify the relationship between the probability of prostate cancer scaled using a 5-point Likert system and the biological characteristics of corresponding tumor foci. METHODS: The present study involved 44 patients undergoing 3.0-Tesla multiparametric MRI before laparoscopic radical prostatectomy. Tracing based on pathological and MRI findings was performed. The relationship between the probability of cancer scaled using the 5-point Likert system and the biological characteristics of corresponding tumor foci was evaluated. RESULTS: A total of 102 tumor foci were identified histologically from the 44 specimens. Of the 102 tumors, 55 were assigned a score based on MRI findings (score 1: n = 3; score 2: n = 3; score 3: n = 16; score 4: n = 11 score 5: n = 22), while 47 were not pointed out on MRI. The tracing study revealed that the proportion of >0.5 cm(3) tumors increased according to the upgrade of Likert scores (score 1 or 2: 33%; score 3: 68.8%; score 4 or 5: 90.9%, χ(2) test, p < 0.0001). The proportion with a Gleason score >7 also increased from scale 2 to scale 5 (scale 2: 0%; scale 3: 56.3%; scale 4: 72.7%; 5: 90.9%, χ(2) test, p = 0.0001). On using score 3 or higher as the threshold of cancer detection on MRI, the detection rate markedly improved if the tumor volume exceeded 0.5 cm(3) (<0.2 cm(3): 10.3%; 0.2-0.5 cm(3): 25%; 0.5-1.0 cm(3): 66.7%; 1.0 < cm(3): 92.1%). CONCLUSIONS: Each Likert scale favobably reflected the corresponding tumor's volume and Gleason score. Our observations show that "score 3 or higher" could be a useful threshold to predict clinically significant carcinoma when considering treatment options.

BACKGROUND: Breast MRI protocols have been improved by using a combination of dynamic scans for bilateral breasts and high-resolution imaging for a single breast which can be obtained during dynamic scans by recent technological advances. The purpose of this study was to compare high-resolution imaging during dynamic scans (HR-intra) with high-resolution imaging obtained post dynamic scans (HR-post). METHODS: Fifty-five women with pathologically proven breast cancer who underwent breast dynamic scans at 3-T MRI from February to September 2009 were enrolled in this study. Tumoral contrasts to the background breast tissue were compared by three radiologists independently in a blinded fashion. Results of visual assessment were categorized into three groups as follows: HR-intra being better (IB), equal (E), and HR-post being better (PB). The contrast to noise ratio (CNR) of the tumor and the signal to noise ratio of the normal breast gland (SNR) were compared between HR-intra and HR-post. RESULTS: Two patients were excluded because of poor MR imaging quality. Three radiologists separately categorized 64.2, 79.2, and 77.4 % of lesions as IB. The CNR of the tumor of HR-intra (mean ± SD = 6.9 ± 4.0) was significantly higher than that of HR-post (6.0 ± 3.7, p < 0.0001). The SNR of the normal breast gland of HR-intra (9.5 ± 1.7) was significantly lower than that of HR-post (10.0 ± 1.9, p < 0.0001). CONCLUSION: HR-intra during dynamic MRI provided earlier and better tumor to normal breast gland contrast than HR-post.

PURPOSE: The staging of endometrial cancer requires surgery which carries the risk of morbidity. FDG PET/CT combined with anatomical imaging may reduce the number of unnecessary lymphadenectomies by demonstrating the risk of extrapelvic infiltration. The purpose of this study was to optimize FDG PET/CT diagnostic criteria for risk assessment in endometrial cancer after first-line risk triage with MRI. METHODS: The study population comprised 37 patients who underwent curative surgery for the treatment of endometrial cancer. First, the risk of extrapelvic infiltration was triaged using MRI. Second, multiple glucose metabolic profiles of the primary lesion were assessed with FDG PET/CT, and these were correlated with the histopathological risk of extrapelvic infiltration including lymphovascular space invasion (LVSI) and high-grade malignancy (grades 2 and 3). The results of histological correlation were used to adjust FDG PET/CT diagnostic criteria. RESULTS: Presurgical assessment using MRI was positive for deep (>50 %) myometrial invasion in 17 patients. The optimal FDG PET/CT diagnostic criteria vary depending on the results of MRI. Specifically, SUVmax (≥16.0) was used to indicate LVSI risk with an overall diagnostic accuracy of 88.2 % in patients with MRI findings showing myometrial invasion. High-grade malignancy did not correlate with any of metabolic profiles in this patient group. In the remaining patients without myometrial invasion, lesion glycolysis (LG) or metabolic volume were better indicators of LVSI than SUVmax with the same diagnostic accuracy of 80.0 %. In addition, LG (≥26.9) predicted high-grade malignancy with an accuracy of 72.2 %. Using the optimized cut-off criteria for LVSI, glucose metabolic profiling of primary lesions correctly predicted lymph node metastasis with an accuracy of 73.0 %, which was comparable with the accuracy of visual assessment for lymph node metastasis using MRI and FDG PET/CT. CONCLUSION: FDG PET/CT diagnostic criteria may need adjustment based on the anatomical information provided by MRI. The optimized criteria can predict the risk of pathology-proven LVSI correctly in 83.8 % of patients before surgery, and thus would improve presurgical treatment planning.

目的：造影超音波検査（CEUS）による乳癌術前化学療法（NAC）の治療効果判定に関する有用性について明らかにすること．<br>対象・方法：2012年9月2013年6月までに，NAC後に乳腺CEUSを施行し，外科的切除を行った乳癌33例35結節（全例女性，平均年齢49.5±12.1歳）を対象とした．造影剤はSonazoidを0.015 mL/kg体重を投与し，投与後1分間撮像した．腫瘍内で最も強く造影効果を認める部位に3 mm径の円形関心領域（ROI）を設定し時間輝度曲線（TIC）を作成し，治療後のTime to peak（TTP, s），Mean transit time（MTT, s）を算出した．病理組織学的治療効果判定（組織判定）は乳癌取扱い規約第17版に則りGrade 03に分類し，Grade 3を完全奏効群，Grade 2以下を非完全奏効群に群別し，CEUSの各項目との比較検討を行った．また，RECISTガイドラインに準じてUS, 造影MRIで腫瘍最大径を計測し治療効果を組織判定と比較した．統計学的検討はMann–WhitneyのU検定，Spearman順位相関係数にて行い，有意水準は5%未満とした．<br>結果：組織判定は，完全奏効群6結節，非完全奏効群29結節であった．CEUSによる治療後評価でTTP（平均値±SD，範囲）は完全奏効群11.7±4.7 s, 4.719.7 s, 非完全奏効群6.0±3.0 s, 2.914.1 sで有意差を認めた（p＝0.006）．MTT（平均値±SD，範囲）においても完全奏効群75.7±72.0 s, 17.2158.8 s, 非完全奏効群15.6±12.5 s, 4.357.7 sで有意差を認めた（p＝0.007）．組織判定とTTP（ρ=0.613, p<0.01），MTT（ρ=0.698, p<0.01）間には中等度の有意な相関が認められた．<br>USによるRECIST評価はPD 1結節，SD 7結節，PR 27結節，CR 0結節．造影MRIによるRECIST評価は，PD 1結節，SD 8結節，PR 22結節，CR4結節であった．RECIST評価とTTP, MTTとの間には有意な相関関係は認められなかった．<br>結語：CEUSは，乳癌NAC後治療効果判定に有用である可能性が示唆された．

目的:乳腺疾患の良悪性鑑別診断に有用な造影超音波(CE-US)所見について検討し明らかにすること．<br>対象・方法:対象は2012年9月2013年6月までに当院で乳腺CE-USを施行し，病理組織学的に確定診断の得られた乳腺疾患75例81病変(全例女性，平均年齢56歳)．組織学的診断は，悪性66病変，良性15病変．装置はAplio 500(東芝メディカルシステムズ株式会社)，造影剤はSonazoid^Ⓡを0.015 mL/kg体重を投与し，投与後1分間撮像した．CE-US所見は，周辺乳腺組織と比較した造影効果(強い/同等/弱い)，B-modeと比較した造影範囲(大きい/同等/小さい)について評価した．raw-dataにて時間輝度曲線を作成し，病変部のTime to peak (TTP, s), Ascending slope (AS, 10-E5 AU/s), Peak intensity (PI, 10-E5 AU), Mean transit time (MTT, s), Area under the curve (AUC, 10-E5 AU), Area under the wash in (AUWI, 10-E5 AU), Area under the wash out (AUWO, 10-E5 AU)を評価した．統計学的検討は，χ²適合度検定とMann-WhitneyのU検定，Tukey-Kramerの検定で行った．<br>結果:周辺乳腺組織と比較した造影効果は76病変で行い，悪性病変では強い60病変，同等3病変，弱い0病変，良性病変では強い3病変，同等6病変，弱い4病変であり，良悪性間で有意差を認めた(p<0.001)． B-modeと比較した造影範囲は79病変で行い，悪性病変では大きい52病変，同等13病変，良性病変では同等13病変，小さい1病変であり，良悪性間で有意差を認めた(p<0.001). AS, PI, AUC, AUWI, AUWOは，良悪性間で有意差を認め，悪性で有意に高値を示した．TTP, MTTは良悪性間で有意差はみられなかった．

In this study, we aimed to compare fat-suppression homogeneity on breast MR imaging by using dual-source parallel radiofrequency excitation and image-based shimming (DS-IBS) with single-source radiofrequency excitation with volume shim (SS-Vol) at 3 Tesla. Twenty patients were included. Axial three-dimensional T1-weighted turbo-field-echo breast images with DS-IBS and SS-Vol were obtained. Fat suppression was scored with four grade points. The contrast of the pectoral muscle and the fat in each breast area was obtained in the head medial, head lateral, foot medial, and foot lateral areas. The axillary space was calculated and compared between DS-IBS and SS-Vol. The average DS-IBS score was significantly higher than that of SS-Vol. The mean contrasts of fat in the foot lateral areas and axillary spaces on DS-IBS images were significantly higher than on SS-Vol images.

OBJECTIVES: To determine the added discriminative value of detailed quantitative characterization of background parenchymal enhancement in addition to the tumor itself on dynamic contrast-enhanced (DCE) MRI at 3.0 Tesla in identifying "triple-negative" breast cancers. MATERIALS AND METHODS: In this Institutional Review Board-approved retrospective study, DCE-MRI of 84 women presenting 88 invasive carcinomas were evaluated by a radiologist and analyzed using quantitative computer-aided techniques. Each tumor and its surrounding parenchyma were segmented semi-automatically in 3-D. A total of 85 imaging features were extracted from the two regions, including morphologic, densitometric, and statistical texture measures of enhancement. A small subset of optimal features was selected using an efficient sequential forward floating search algorithm. To distinguish triple-negative cancers from other subtypes, we built predictive models based on support vector machines. Their classification performance was assessed with the area under receiver operating characteristic curve (AUC) using cross-validation. RESULTS: Imaging features based on the tumor region achieved an AUC of 0.782 in differentiating triple-negative cancers from others, in line with the current state of the art. When background parenchymal enhancement features were included, the AUC increased significantly to 0.878 (p<0.01). Similar improvements were seen in nearly all subtype classification tasks undertaken. Notably, amongst the most discriminating features for predicting triple-negative cancers were textures of background parenchymal enhancement. CONCLUSIONS: Considering the tumor as well as its surrounding parenchyma on DCE-MRI for radiomic image phenotyping provides useful information for identifying triple-negative breast cancers. Heterogeneity of background parenchymal enhancement, characterized by quantitative texture features on DCE-MRI, adds value to such differentiation models as they are strongly associated with the triple-negative subtype. Prospective validation studies are warranted to confirm these findings and determine potential implications.

The aim of this study was to explore whether the regional peak longitudinal (LS) and circumferential strains (CS) at the right ventricular (RV) free wall could be used to identify global RV dysfunction in relation to RV ejection fraction (RVEF) and plasma concentration of brain natriuretic peptide (BNP) in pulmonary hypertension (PH). A total of 37 consecutive patients diagnosed with PH and 13 healthy control subjects were included. Fast strain encoded and routine cine MRI was performed. The LS and CS at three RV levels were quantified and their relations with RVEF and BNP were investigated. Receiver operating characteristic (ROC) analysis was employed to assess the diagnostic utility of strain encoded MRI for the detection of low RVEF. Significant correlations with LS were observed for RVEF and BNP. Compared to CS, LS showed better correlation with RVEF. The mid-ventricular level of RV was the most sensitive site for evaluation of RV dysfunction. According to our ROC analysis, LS showed higher sensitivity and specificity to detect low RVEF. Compared to CS, LS showed stronger correlations with RVEF and BNP and could be a good detector of RV dysfunction in PH.