Areas Of Low Signal Intensity Research Articles

Enhanced Image Processing Using Complex Averaging in Diffusion-Weighted Imaging of the Prostate: The Impact on Image Quality and Lesion Detectability.

Diffusion-weighted images of the prostate can suffer from a "hazy" background in low signal-intensity areas. We hypothesize that enhanced image processing (EIP) using complex averaging reduces artifacts, noise, and distortion in conventionally acquired diffusion-weighted images and synthesized high b-value images, thus leading to higher image quality and better detection of potentially malignant lesions. Conventional DWI trace images with a b-value of 1000 s/mm2 (b1000), calculated images with a b-value of 2000 s/mm2 (cb2000), and ADC maps of 3T multiparametric prostate MRIs in 53 patients (age 68.8 ± 10 years) were retrospectively evaluated. Standard images were compared to images using EIP. In the standard images, 36 lesions were detected in the peripheral zone and 20 in the transition zone. In 13 patients, EIP led to the detection of 8 additional lesions and the upgrading of 6 lesions; 6 of these patients were diagnosed with prostate carcinoma Gleason 7 or 8. EIP improved qualitative ratings for overall image quality and lesion detectability. Artifacts were significantly reduced in the cb2000 images. Quantitative measurements for lesion detectability expressed as an SI ratio were significantly improved. EIP using complex averaging led to image quality improvements in acquired and synthesized DWI, potentially resulting in elevated diagnostic accuracy and management changes.

Peculiarities of spinal epidural abscess in COVID-19 patients: a literature review

During the SARS-CoV-2 pandemic, some authors described an increased incidence of primary Spinal Epidural Abscess (SEA) in COVID-19 patients with clinical and radiological peculiarities. Early recognition of this disease remains challenging, resulting in delayed diagnosis and significant morbidity and mortality. The authors performed a systematic review of the literature in PubMed, Cochrane, and Scopus about the traditional form of SEA comparing the main features related to COVID-19 SEA. The search was performed from 1990 to 2020. Magnetic Resonance Imaging with contrast is mandatory to recognize this kind of lesion in order to obtain a differential diagnosis. COVID-19 SEAs are generally active abscesses, with a large cystic component. Gadolinium-enhanced MR images can aid in the definition of the age and consistency of the abscess. A rim of tissue that enhances after the injection of gadolinium represents granulation tissue; liquid pus is associated with an area of low signal intensity on T1-weighted images. This new type of SEA in COVID-19 patients showed several differences also in clinical features. No evidence of an external infective source was found (spondylodiscitis, surgery, or percutaneous treatment). None of the patients was a drug abuser and MSSA was the only responsible pathogen. The cervicothoracic spine was the most involved site. Further studies are needed to confirm these preliminary findings.

Benefits of high-dielectric pad for neuroimaging study in 7-Tesla MRI

This study aimed to evaluate whether the use of a high-dielectric pad is effective in increasing transmit and receive sensitivity in areas of low signal intensity in the human brain at high magnetic fields and assess its usefulness in neuroimaging studies. The novelty of this study lies in the first reported use of diffusion tensor imaging (DTI) results to evaluate the effect of the pad on neuroimaging. Six volunteers underwent MR scanning using a 7 T MR system. T1-weighted images (T1w) and diffusion-weighted images (DWI) were acquired to demonstrate the benefits of a high-dielectric pad made of barium titanate (BaTiO3). For all imaging experiments, two datasets were acquired per person, one with and one without a high-dielectric pad. Enhancement of signal sensitivity in neuroimaging has been analyzed by DTI study. Higher signal intensities and spatial contrast were demonstrated in the in T1w images acquired using high-dielectric pad than in those acquired without high-dielectric pad. Especially in DTI studies, increased quantitative anisotropy (QA) signals were observed in the corticospinal tract (CST), frontopontine tract (FPT), splenium of corpus callosum (SCC), fornix (FX), inferior fronto-occipital fasciculus (IFOF), cerebellum (CB), middle cerebellar peduncle (MCP), and body of corpus callosum (BCC) (FDR < 0.05). The signal differences accounted for an overall 20% increase. A high-dielectric pad is effective in enhancing signal intensity in human brain images acquired using 7 T MRI. Our results show that the use of such pad can increase the spatial resolution, tissue contrast, and signal intensity in neuroimaging studies. These findings suggest that high-dielectric pads may provide a relatively simple and low-cost method for spatiotemporal brain imaging studies.

Primary synovial sarcoma of the shoulder: Case report of the “triple sign” on proton density magnetic resonance imaging

The first case of synovial sarcoma was published in 1893. The disease is a type of primary malignancy of the soft tissues. It is a rare and aggressive neoplasm of unknown tissue origin, characterized by strong metastatic potential and poor prognosis. The present case of a 64-year-old male patient with pain and swelling in his right shoulder and progressive loss of movement demonstrates an uncommon location for the neoplasm. Magnetic resonance proton-density fat-suppressed turbo spin-echo sequences show a heterogeneous mass in the right shoulder. The lack of homogeneity in the signal has been described in medical literature as the "triple sign" and is represented by low, intermediate, and high signal intensity areas through the neoplasm. Visible serpentine vessels spread through the tumor. There was a visible metastatic disease in the regional lymph nodes and metastatic foci in the adjacent bones. Pathological analysis of the tumor confirmed the diagnosis of biphasic synovial sarcoma. An oncological committee advised chemotherapy and radiotherapy. More prominent magnetic resonance imaging findings in synovial sarcoma that may facilitate the diagnostic process are the inhomogeneity and "triple sign" in proton density and T2 sequences, multilobulated tumors, septa, irregular borders, serpentine vascular channels, engagement of the adjacent bones and bone marrow, and involvement of the joint synovia.

Sarcomatoid renal cell carcinoma: MRI features and their association with survival

ObjectiveTo evaluate MRI features of sarcomatoid renal cell carcinoma (RCC) and their association with survival.MethodsThis retrospective single-center study included 59 patients with sarcomatoid RCC who underwent MRI before nephrectomy during July 2003–December 2019. Three radiologists reviewed MRI findings of tumor size, non-enhancing areas, lymphadenopathy, and volume (and percentage) of T2 low signal intensity areas (T2LIA). Clinicopathological factors of age, gender, ethnicity, baseline metastatic status, pathological details (subtype and extent of sarcomatoid differentiation), treatment type, and follow-up were extracted. Survival was estimated using Kaplan-Meier method and Cox proportional-hazards regression model was used to identify factors associated with survival.ResultsForty-one males and eighteen females (median age 62 years; interquartile range 51–68) were included. T2LIAs were present in 43 (72.9%) patients. At univariate analysis, clinicopathological factors associated with shorter survival were: greater tumor size (> 10 cm; HR [hazard ratio] = 2.44, 95% CI 1.15–5.21; p = 0.02), metastatic lymph nodes (present; HR = 2.10, 95% CI 1.01–4.37; p = 0.04), extent of sarcomatoid differentiation (non-focal; HR = 3.30, 95% CI 1.55–7.01; p < 0.01), subtypes other than clear cell, papillary, or chromophobe (HR = 3.25, 95% CI 1.28–8.20; p = 0.01), and metastasis at baseline (HR = 5.04, 95% CI 2.40–10.59; p < 0.01). MRI features associated with shorter survival were: lymphadenopathy (HR = 2.24, 95% CI 1.16–4.71; p = 0.01) and volume of T2LIA (> 3.2 mL, HR = 4.22, 95% CI 1.92–9.29); p < 0.01). At multivariate analysis, metastatic disease (HR = 6.89, 95% CI 2.79–16.97; p < 0.01), other subtypes (HR = 9.50, 95% CI 2.81–32.13; p < 0.01), and greater volume of T2LIA (HR = 2.51, 95% CI 1.04–6.05; p = 0.04) remained independently associated with worse survival.ConclusionT2LIAs were present in approximately two thirds of sarcomatoid RCCs. Volume of T2LIA along with clinicopathological factors were associated with survival.

Assessment of Age-Related Changes in Normal Clivus Bone Marrow Using Clivus-to-Corpus Callosum Signal Intensity Ratio on Magnetic Resonance Imaging

Objective: To assess whether the signal intensity ratio of the clivus to corpus callosum (clivus/CC) depends on age. Materials and Methods: A retrospective study of 244 subjects investigated the magnetic resonance imaging (MRI) appearance of the clivus on T1-weighted sagittal images. Both qualitative and quantitative assessments of MRIs were evaluated. In qualitative assessment, signal intensity patterns of clivus were graded from I to III, according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, the authors performed multivariable Gaussian regression analysis to assess the association of age categorized by decades and the signal intensity ratio of clivus/CC and clivus to cerebrospinal fluid (clivus/CSF). Results: Grade I clivus was found in about 40% of the age 1 to 9, whereas Grade III clivus was more frequent at more than 15% in the age over 50. There were statistically different in the mean values of clivus/CSF and clivus/CC signal intensity ratios by grades. The mean values of clivus/CSF and clivus/CC signal intensity ratios were increased by ages in both genders, but slightly higher in males. In unadjusted analyses, the differences in mean values of clivus/CC signal intensity ratio were larger by increasing age. After adjustment for gender, the difference in mean values remained the same. Conclusion: There was an age-related pattern of clivus bone marrow intensity. Since the use of CC as a new landmark showed a similar pattern as of pons, the ratio of clivus/CC signal intensity may be used as an alternative measurement in brain MRI. Keywords: Clivus; Bone marrow; Magnetic resonance imaging (MRI); Corpus callosum (CC)

Skull Base Chordoma: The Thumb Sign

A 57 year old woman with no past medical history presented with headaches and progressive left vision loss. Subsequently, a contrast enhanced brain MRI was performed showing a large well defined skull base mass located laterally in the left petro clival fissure, exhibiting high T2 and FLAIR signal intensity (Figure A), with areas of low signal intensity on susceptibility weighted images consistent with calcifications and a heterogenous enhancement after injection. This tumor was responsible for mass effect on the orbital apex and optic nerve anteriorly and the mesio temporal lobe laterally. Most importantly, on the sagittal planes we can see the tumor projection indenting the pons which is displaced posteriorly. This finding is known as the thumb sign (Figure B and C) characteristic of chordomas. Given these MRI features and after a stereotactic biopsy the diagnosis of chordoma of the skull base was confirmed. Because of the major local extension, the patient underwent radiotherapy rather than surgical resection. Chordomas are rare skull base tumors arising from embryonal rest cells [1]. The major differential being chondrosarcomas with similar appearance but higher ADC values. The thumb sign is relatively specific of chordomas [2] although itcan be described in chondromas of the skull base and can also be seen in chondrosarcomas.

Magnetic resonance imaging features of a solitary fibrous tumor of the vulva: a case report

Solitary fibrous tumors (SFTs) are commonly seen in the pleura. SFT involvement of the vulva is rare, and clinical diagnosis is mainly based on histopathological and immunohistochemical analyses. We herein describe the imaging features of a 69-year-old woman with an SFT of the vulva. The SFT was hypointense on T1-weighted images, similar to muscle; however, it showed inhomogeneous hyperintensity predominantly on fat-suppressed T2-weighted images. An area of low signal intensity was evident on T2-weighted images, and the tumor showed progressive enhancement in delayed phases. The tumor also displayed heterogeneous and prolonged, persistent enhancement, and serpentine vessels were present in the peritumoral area as signal voids. Pathological examination confirmed that the lesion was an atypical SFT originating from the vulva, and it was composed of spindle cells and perivascular and stromal hyalinization. This case reveals the characteristic imaging findings of vulvar SFT and their association with the relevant pathological findings, thus contributing to the primary diagnosis and preoperative evaluation of this potentially aggressive tumor.

Age-Related Changes in Signal Intensity Ratio of Normal Clivus Bone Marrow on Magnetic Resonance Imaging

Objective: To evaluate the association between the signal intensity ratio of clivus bone displayed on magnetic resonance (MR) imaging and ages.Materials and Methods: A retrospective cohort study of 268 patients underwent brain MR imaging during January 2015 to October 2019. We qualitatively and quantitatively assessed bone marrow signal intensity of clivus bone that were performed on T1-weighted sagittal images. In qualitative assessment, the signal intensities of clivus were visually graded from Grade I to III according to the proportion of low and high signal intensity areas occupying the clival marrow region. In quantitative assessment, we evaluated the association between the signal intensity ratio of clivus to pons and age categorized by decades in multivariable Gaussian regression analysis.Results: Of 268 patients, the ratio of males to females is 1:1. Grade I clivus was found about 35% of the age 1-9 years, whereas Grade 3 clivus was more frequent (more than 13%) in the ages over 30 years. There were statistically different in the mean values of clivus/CSF and clivus/pons signal intensity ratios by grades. The mean values of clivus/CSF and clivus/pons signal intensity ratios were increased by ages in both sexes, but slightly higher in males. In regression analysis after adjustment for sex, the differences in mean values of clivus/pons signal intensity ratios were larger by increasing age, using the age 1-9 as a reference group.Conclusion: The present study confirms that signal intensity ratios of clivus to pons on T1-weighted sagittal MR images is increased with ages.

Cardiac Magnetic Resonance Radiomics Reveal Differential Impact of Sex, Age, and Vascular Risk Factors on Cardiac Structure and Myocardial Tissue.

Background: Cardiovascular magnetic resonance (CMR) radiomics analysis provides multiple quantifiers of ventricular shape and myocardial texture, which may be used for detailed cardiovascular phenotyping.Objectives: We studied variation in CMR radiomics phenotypes by age and sex in healthy UK Biobank participants. Then, we examined independent associations of classical vascular risk factors (VRFs: smoking, diabetes, hypertension, high cholesterol) with CMR radiomics features, considering potential sex and age differential relationships.Design: Image acquisition was with 1.5 Tesla scanners (MAGNETOM Aera, Siemens). Three regions of interest were segmented from short axis stack images using an automated pipeline: right ventricle, left ventricle, myocardium. We extracted 237 radiomics features from each study using Pyradiomics. In a healthy subset of participants (n = 14,902) without cardiovascular disease or VRFs, we estimated independent associations of age and sex with each radiomics feature using linear regression models adjusted for body size. We then created a sample comprising individuals with at least one VRF matched to an equal number of healthy participants (n = 27,400). We linearly modelled each radiomics feature against age, sex, body size, and all the VRFs. Bonferroni adjustment for multiple testing was applied to all p-values. To aid interpretation, we organised the results into six feature clusters.Results: Amongst the healthy subset, men had larger ventricles with dimmer and less texturally complex myocardium than women. Increasing age was associated with smaller ventricles and greater variation in myocardial intensities. Broadly, all the VRFs were associated with dimmer, less varied signal intensities, greater uniformity of local intensity levels, and greater relative presence of low signal intensity areas within the myocardium. Diabetes and high cholesterol were also associated with smaller ventricular size, this association was of greater magnitude in men than women. The pattern of alteration of radiomics features with the VRFs was broadly consistent in men and women. However, the associations between intensity based radiomics features with both diabetes and hypertension were more prominent in women than men.Conclusions: We demonstrate novel independent associations of sex, age, and major VRFs with CMR radiomics phenotypes. Further studies into the nature and clinical significance of these phenotypes are needed.

Reviewing Bone Marrow Edema in Athletes: A Difficult Diagnostic and Clinical Approach.

Bone marrow edema (BME) is defined as an area of low signal intensity on T1-weighted (T1W) MRI images and associated with intermediate or high signal intensity findings on T2-weighted (T2W) MRI images. BME represents a typical imaging finding that characterizes common stress-related bone injuries of professional and amateur athletes. The etiology of stress-related injuries is influenced by numerous factors, including the initiation of a new sports activity or changes in an existing training protocol. The clinical significance of BME remains unclear. However, a correlation between the imaging pattern of BME, the clinical history of the patient and the type of sports activity practiced is essential for correct diagnosis and adequate therapeutic treatment. It is also important to clarify whether there is a specific threshold beyond which exercise can adversely affect the bone remodeling process, as the clinical picture may degenerate into the presence of BME, pain and, in the most severe cases, bone loss. In our review, we summarize the current knowledge on the etiopathogenesis and treatment options for BME and highlight the main aspects that make it difficult to formulate a correct diagnosis and establish an adequate therapeutic treatment.

Non-echoplanar diffusion weighed imaging and T1-weighted imaging for cholesteatoma mastoid extension

ObjectivesA broad mastoid extension limits cholesteatoma resection via a transmeatal approach including endoscopic ear surgery. Therefore, a preoperative diagnosis of mastoid extension is a the most critical factor to determine whether to perform mastoidectomy. The purpose of this study was to assess the efficacy of non-echoplanar diffusion-weighted imaging (non-EPI DWI) and T1-weighted imaging in the evaluation of mastoid extension in cholesteatomas of the middle ear. MethodsPatients who underwent magnetic resonance imaging (MRI) for pretreatment evaluation before primary surgery for pars flaccida or tensa cholesteatoma, which revealed a high-signal intensity in the mastoid on T2-weighed imaging were retrospectively evaluated. Two board-certified radiologists retrospectively evaluated the extent of cholesteatomas on MRI with non-EPI DWI, non-EPI DWI- and T1-weighted axial imaging. The presence of a high signal intensity on non-EPI DWI or low or high signal intensity on T1-weighted imaging in the mastoid was evaluated. All cases were subclassified as M+ (surgically mastoid extension-positive) or M- (surgically mastoid extension-negative). ResultsA total of 59 patients with middle ear cholesteatoma were evaluated. There were 37 M+ cases and 22 M- cases. High-signal intensity on non-EPI DWI exhibited a sensitivity of 0.89 and specificity of 0.82, whereas partial low-signal intensity on T1-weighted imaging exhibited a sensitivity of 0.84 and specificity of 0.91 for detecting mastoid involvement. Complete high-signal intensity on T1-weighted imaging exhibited a sensitivity of 0.73 and specificity of 0.89 for detecting non-involvement of the mastoid. The sensitivity (0.92) and specificity (0.96) of combined non-EPI DWI and T1-weighted imaging evaluation were higher than those of with non-EPI DWI or T1-weighted imaging alone. The interobserver agreement for the presence of high-signal intensity in the mastoid cavity on non-EPI DWI was very good at 0.82, that of a partial low-signal intensity area in the mastoid cavity lesions on T1-weighted imaging was good, at 0.76 and that of complete high-signal intensity in the mastoid cavity lesions on T1-weighted imaging was good, at 0.67. ConclusionsThe signal intensity on non-EPI DWI and T1-weighted imaging of the mastoid could be used to accurately assess the extent of middle ear cholesteatoma, which could facilitate surgical treatment planning.

Diagnostic Algorithm to Differentiate Benign Atypical Leiomyomas from Malignant Uterine Sarcomas with Diffusion-weighted MRI.

Background Improving the differentiation of uterine sarcomas from atypical leiomyomas remains a clinical challenge and is needed to avoid inappropriate surgery. Purpose To develop a diagnostic algorithm including diffusion-weighted MRI criteria to differentiate malignant uterine sarcomas from benign atypical leiomyomas. Materials and Methods This case-control retrospective study identified women with an atypical uterine mass at MRI between January 2000 and April 2017, with surgery or MRI follow-up after 1 year or longer. A diagnostic algorithm including T2-weighted MRI and diffusion-weighted imaging (DWI) signal and apparent diffusion coefficient (ADC) values was developed to predict for sarcoma. The training set consisted of 51 sarcomas and 105 leiomyomas. Two external validation sets were used to evaluate interreader reproducibility (16 sarcomas; 26 leiomyomas) and impact of reader experience (29 sarcomas; 30 leiomyomas). Wilson confidence intervals (CIs) were calculated for sensitivity and specificity. Results Evaluated were 156 women (median age, 50 years; interquartile range, 44-63 years). Predictive MRI criteria for malignancy were enlarged lymph nodes or peritoneal implants, high DWI signal greater than that in endometrium, and ADC less than or equal to 0.905 × 10-3 mm2/sec. Conversely, a global or focal area of low T2 signal intensity and a low or an intermediate DWI signal less than that in endometrium or lymph nodes allowed readers to confidently diagnose as benign a uterine mass demonstrating one or more of these signs (P < .001) in 100% cases in all three data sets. The sensitivities and specificities of the algorithm for diagnosis of malignancy were 98% (50 of 51 masses; 95% CI: 90%, 100%) and 94% (99 of 105 masses; 95% CI: 88%, 98%) in the training set; 88% (14 of 16 masses; 95% CI: 64%, 97%) and 100% (26 of 26 masses; 95% CI: 87%, 100%) in the validation set; and 83% (24 of 29 masses; 95% CI: 65%, 92%) and 97% (29 of 30 masses; 95% CI: 83%, 99%) for the less experienced reader, respectively. Conclusion A diagnostic algorithm with predictive features including lymphadenopathy, high diffusion-weighted imaging signal with reference to endometrium, and low apparent diffusion coefficient enabled differentiation of malignant sarcomas from atypical leiomyomas, and it may assist inexperienced readers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Méndez in this issue.

Bone Marrow Edema and Joint Overuse in Athletes: a Mini-Review

Bone marrow edema (BME) on MRI is defined as an area of low signal intensity on Tl-weighted MR images and associated...

T2* Placental Magnetic Resonance Imaging in Preterm Preeclampsia

Placental dysfunction underlies the cause of pregnancies complicated by preeclampsia. The use of placental magnetic resonance imaging to provide an insight into the pathophysiology of preeclampsia and thus assess its potential use to inform prognosis and clinical management was explored. In this prospective observational cohort study, 14 women with preterm preeclampsia and 48 gestation-matched controls using 3-Tesla magnetic resonance imaging at median of 31.6 weeks (interquartile range [IQR], 28.6-34.6) and 32.2 weeks (IQR, 28.6-33.8), respectively, were imaged. The acquired data included T2-weighted images and T2* maps of the placenta, the latter an indicative measure of placental oxygenation. Placentae in women with preeclampsia demonstrated advanced lobulation, varied lobule sizes, high granularity, and substantial areas of low-signal intensity on T2-weighted imaging, with reduced entire placental mean T2* values for gestational age (2 sample t test, t=7.49) correlating with a reduction in maternal PlGF (placental growth factor) concentrations (Spearman rank correlation coefficient 0.76) and increased lacunarity values (t=3.26). Median mean T2* reduced from 67 ms (IQR, 54-73) at 26.0 to 29.8 weeks' gestation to 38 ms (IQR, 28-40) at 34.0 to 37.9 weeks' gestation in the control group. In women with preeclampsia, median T2* was 23 ms (IQR, 20-23) at 26.0 to 29.8 weeks' gestation and remained low (22 ms [IQR, 20-26] at 34.0-37.8 weeks' gestation). Histological features of maternal vascular malperfusion were only found in placentae from women with preeclampsia. Placental volume did not differ between the control group and women with preeclampsia. Placental magnetic resonance imaging allows both objective quantification of placental function in vivo and elucidation of the complex mechanisms underlying preeclampsia development.

Approaching the forensic significance of possible PMMR correlates in a case of assumed cardiac rigor mortis

Abstract We demonstrate a left ventricular subendocardial ring as low signal intensity (SI) findings in a T2-weighted image (T2WI) sequence in postmortem magnetic resonance (PMMR) imaging. As plausible explanation, we propose rigor mortis of the heart muscle and discuss the implications of that. An 18-year-old man with a previous history of arrhythmia suddenly went into cardiopulmonary arrest while eating. Although cardiopulmonary resuscitation was performed for 120 min, death was confirmed. Autopsy revealed the cause of death to be sudden cardiac death due to arrhythmia induced by arrhythmogenic right ventricular cardiomyopathy. In this case, PMMR imaging performed before autopsy demonstrated a low SI area in the subendocardial region, suggesting a cardiac rigor mortis on the short-axial T2WI, apparent diffusion coefficient (ADC) map, and diffusion-weighted image (DWI). Low SI on T2WI is considered to be lesser interstitial fluids distribution in more-pressured subendocardial region, low SI on ADC map to be higher viscosity in subendocardial region, and low SI on DWI to be T2 blackout effect. PMMR imaging may delineate a correlate for assumed cardiac rigor mortis, which seems to be practically impossible to reliably identify macroscopically.

In situ high-precision lithium isotope analyses at low concentration levels with femtosecond-LA-MC-ICP-MS

Precision of a single measurement in the low signal intensity area is better with a combination of a 1013 Ω amplifier and a SEM.

Differentiating benign and malignant inflammatory breast lesions: Value of T2 weighted and diffusion weighted MR images

ObjectivesBenign and malignant inflammatory breast lesions demonstrate similar findings on both T2 weighted imaging (T2WI) and dynamic contrast enhanced (DCE) images. We hypothesized that benign inflammatory lesions might be differentiated form malignancies using a combination of apparent diffusion coefficient (ADC) values derived from diffusion weighted images (DWI) and T2WI. Materials and methodsWe retrospectively reviewed 162 patients undergoing breast MRI (T2WI, DWI and DCE images) between 2008 and 2015 who had breast lesions with high T2WI signal intensity (High T2 SI) including 14 benign inflammatory lesions, 69 benign non-inflammatory lesions, 16 malignant inflammatory lesions and 63 malignant non-inflammatory lesions. On the High T2 SI and low T2WI signal intensity (Low T2 SI) areas in these breast lesions, we calculated ADC values from b values of 0 and 1000 s/mm2. ResultsThe mean ADC values ± standard deviation (10−3 mm2/s) of the High T2 SI areas in benign inflammatory, benign non-inflammatory, malignant inflammatory and malignant non-inflammatory breast lesions were 0.75 ± 0.18, 1.77 ± 0.33, 2.06 ± 0.32 and 1.88 ± 0.41, respectively. Those of the Low T2 SI areas in benign inflammatory, benign non-inflammatory, malignant inflammatory and malignant non-inflammatory lesions were 0.89 ± 0.15, 1.31 ± 0.28, 0.87 ± 0.20 and 0.94 ± 0.27 respectively. ADC values of High T2 SI areas of the benign inflammatory lesions were significantly lower than those of benign non-inflammatory, malignant inflammatory, and malignant non-inflammatory lesions (p < 0.001). ADC values of Low T2 SI areas in benign inflammatory lesions were not significantly different from those of malignant inflammatory (p = 0.99) or malignant non-inflammatory lesions (p = 0.72). ConclusionFor breast lesions with High T2 SI, segmenting the High T2 SI for ADC mapping distinguishes benign from malignant inflammatory conditions. Using ADC mapping of the Low T2 SI areas will not result in this distinction.

敗血症性DICに陥った子宮腺筋症の1例(A case of uterine adenomyosis complicated by septic disseminated intravascular coagulation)

要旨子宮腺筋症はしばしば経験するが，これまでに腺筋症内に感染を来し敗血症に陥ったという報告はほとんどない。今回，敗血症性DIC（disseminated intravascular coagulation）に陥った子宮腺筋症の症例を経験した。内科的治療に抵抗性であったが，子宮を摘出することで全身状態はすみやかに改善した。症例は50歳の女性。以前から月経周期不整であった。前日から発熱と下腹部痛を訴え，来院時に強い反跳痛と筋性防御を認めた。骨盤部MRI検査で子宮は12cmに腫大していたが，明らかな感染の所見はなかった。子宮腺筋症に感染を併発した敗血症を疑い，抗菌薬治療を開始した。入院3日目にはSOFAスコアは12点に，急性期DICスコアは6点に上昇した。内科的治療では改善が見込めないと判断し，同日に腹式子宮全摘術を施行した。摘出した子宮の割面から膿汁の流出を認め，腺筋症内に感染を合併していたことが判明した。術後すみやかに循環動態が回復し，炎症反応も低下した。子宮腺筋症に感染を合併した場合，確定診断を得るのは難しい。自験例のように敗血症性DICに陥ることがあり，内科的治療が奏効しない場合は手術を考慮する必要がある。

Analysis of Threshold Doses for Radiation Induced Liver Parenchymal Changes on MRI after Real Time–Image Gated Spot-Scanning Proton Beam Therapy of Hepatocellular Carcinomas

Radiation induced liver parenchymal changes after radiation therapy is depicted as a focal area of low signal intensity (FLSI) around the irradiated liver tumor on images of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). In 2014, we developed a real-time tumor-tracking function with two sets of fluoroscopic X-ray sources in the gantry and put it to use with spot-scanning proton beam therapy for moving tumors, we have called this real-time-image gated spot-scanning proton beam therapy (RGPT). The purpose of this study is to analyze the threshold dose (TD) for FLSI on Gd-EOB-DTPA-enhanced MRI after RGPT for hepatocellular carcinomas (HCC). We retrospectively reviewed patients with HCC treated by RGPT from December 2014 to October 2016 and followed this up with MRI using Gd-EOB-DTPA 3 months after the RGPT in our institution. We identified 10 patients with 11 lesions. Five patients had liver cirrhosis among the 10 patients. Before the RGPT, the median Child-Pugh score was 5 (range: 5-7) and nine patients were evaluated as Child -Pugh class A, with one as class B. The mean gross tumor volume was 33 ± 37 ml. Five patients received 76 Gy (relative biological effectiveness: RBE) in 20 fractions, three 72.6 Gy (RBE) in 22 fractions, and two patients with three lesions 66 Gy (RBE) in 10 fractions. We defined the FLSI as the low signal intensity area around the irradiated liver tumors on images in the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI 3 months after RGPT. The FLSI and the whole liver 3 months after RGPT were visually delineated. When we calculated the threshold dose (TD) for FLSI using a dose volume histogram, we adopted the non-FLSI liver volume (whole liver volume 3 months after RGPT minus the FLSI volume) to mitigate the impact of the shrinkage of the irradiated tumor and liver parenchyma within the FLSI. To analyze the TD among three treatment regimens, we used the equivalent dose in 2 Gy (RBE) fractions using a linear-quadratic model, assuming an α/β of 3. The mean liver volume before and after RGPT were 1278 ± 218 ml and 1218 ± 221 ml, respectively. The mean FLSI volume and non-FLSI liver volume were 143 ± 108 ml and 1061 ± 244 ml, respectively. The mean TD in 2Gy (RBE) fractions was 36.9 ± 11.0 Gy (RBE). The mean TD for patients with and without liver cirrhosis were 38.2 ± 10.8 Gy (RBE) and 34.9 ± 12.6 Gy (RBE), respectively (p = 0.673). The threshold dose for FLSI after RGPT on Gd-EOB-DTPA-enhanced MRI could be estimated in the RGPT planning for HCC. This would seem to be potentially useful in predicting liver damage before RGPT and prevent serious events in the following therapy.