Contrast-enhanced Fat-suppressed T1-weighted Images Research Articles

Uterine Inversion.

HomeRadioGraphicsVol. 43, No. 6 PreviousNext Cases from the Cooky JarFree AccessUterine InversionKaitlin M. Zaki-Metias , Melina Hosseiny, Fardad Behzadi, Patricia BalthazarKaitlin M. Zaki-Metias , Melina Hosseiny, Fardad Behzadi, Patricia BalthazarAuthor AffiliationsFrom the Department of Radiology, Trinity Health Oakland Hospital/Wayne State University School of Medicine, 44405 Woodward Ave, Medical Education, Pontiac, MI 48341 (K.M.Z.M.); Department of Radiology, University of California San Diego, San Diego, Calif (M.H.); Department of Radiology, Brigham and Women's Hospital/Harvard Medical School, Boston, Mass (F.B.); and Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Ga (P.B.).Address correspondence to K.M.Z.M. (email: [email protected]).Kaitlin M. Zaki-Metias Melina HosseinyFardad BehzadiPatricia BalthazarPublished Online:May 18 2023https://doi.org/10.1148/rg.230004MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Uterine inversion, or uterine intussusception, is a rare, potentially life-threatening entity characterized by inversion of the fundus into the uterine cavity, which often manifests as an acute complication of childbirth (1,2). Less commonly, uterine inversion is nonpuerperal, occurring as a result of an endometrial or myometrial mass (2,3). Patients typically present with symptoms that include vaginal bleeding and pelvic pain.At MRI, uterine inversion appears as a U-shaped uterus with loss of the normal convex fundal contour on sagittal images (Fig 1A, 1B) (2). A target configuration may be visualized on axial images, representing the concentric serosa, myometrium, and endometrium (Fig 1C, 1D) (2). MRI is also useful in assessing the cause in patients with nonpuerperal uterine inversion, including submucosal leiomyomas, uterine leiomyosarcomas, and endometrial malignancies. There are four grades of uterine inversion, which are characterized by the degree of inferior bowing of the fundus relative to the cervix and/or vaginal introitus (Fig 2).Figure 1. Uterine inversion in a previously healthy premenopausal female patient with acute onset of pelvic pain and vaginal bleeding. A bleeding vaginal or cervical mass was suspected on physical examination, and pelvic MRI was performed for further evaluation. Sagittal T2-weighted (A) and contrast-enhanced fat-suppressed T1-weighted (B) MR images of the pelvis demonstrate a U-shaped uterus (U) with loss of the normal fundal contour, with protrusion of the fundus into the distended vaginal canal (V), consistent with grade III uterine inversion. The cervix (C) is located superior to the inverted fundus. At the fundus, there is an ill-defined rounded lesion (arrow in A and B) with heterogeneous T1 signal intensity and enhancement with irregular margins, with adjacent heterogeneous T2 signal intensity and increased T1 signal intensity. The findings are most consistent with a hemorrhagic submucosal uterine leiomyoma. Axial T2-weighted (C) and contrast-enhanced fat-suppressed T1-weighted (D) MR images of the pelvis show concentric rings of signal intensity indicating the serosa, myometrium, endometrium, and vagina.Figure 1.Download as PowerPointOpen in Image Viewer Figure 2. Illustration depicts the normal anatomic position of the uterus (A) and the various grades of inversion. Grade I uterine inversion (B) is characterized by inferior bowing of the fundus up to but not beyond the cervix. In grade II uterine inversion (C), the inverted fundus protrudes through the cervix and into the vagina. The uterus is fully inverted and protrudes out of the vagina in grade III uterine inversion (D).Figure 2.Download as PowerPointOpen in Image Viewer Disclosures of conflicts of interest.—K.M.Z.M. Meeting attendance and travel reimbursement from Trinity Health Oakland Hospital. P.B. Editorial board member of RadioGraphics, Association of University Radiologists GE Radiology Research Academic Fellowship, meeting travel reimbursement from the American College of Radiology.K.M.Z.M and P.B. have provided disclosures (see end of article); all other authors have disclosed no relevant relationships.

Assessment of squamous cell carcinoma of the floor of the mouth with magnetic resonance imaging

PurposeWe aimed to use magnetic resonance imaging (MRI) to determine the relationship between the pathological depth of invasion (DOI), undetectability, and tumor thickness of squamous cell carcinoma of the floor of the mouth.Materials and methodsWe retrospectively evaluated the relationship between pathological DOI and MRI detectability, as well as the relationship between pathological DOI and tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging or coronal T2-weighted imaging.ResultsWe analyzed 30 patients with squamous cell carcinoma of the floor of the mouth; MRI revealed that the pathological DOI of the 11 undetectable lesions (median 2 mm) was smaller than that of the 19 detectable lesions (median 14 mm) (p < 0.001), and the cut-off value was 3 mm (sensitivity, 0.84; specificity, 0.91; area under the curve, 0.89). Tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging was assessed in all 19 detectable lesions; however, tumor thickness on coronal T2-weighted imaging could not be assessed in eight cases. Tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging was found to be significantly associated with the pathological DOI.ConclusionsUndetectability on MRI indicates superficial lesions with a pathological DOI value that is less than 3 mm. In detectable lesions, tumor thickness on coronal fat-suppressed contrast-enhanced T1-weighted imaging is associated with pathological DOI.

MRI-based radiomics signature for pretreatment prediction of pathological response to neoadjuvant chemotherapy in osteosarcoma: a multicenter study.

To develop and validate a radiomics signature based on magnetic resonance imaging (MRI) from multicenter datasets for preoperative prediction of pathologic response to neoadjuvant chemotherapy (NAC) in patients with osteosarcoma. We retrospectively enrolled 102 patients with histologically confirmed osteosarcoma who received chemotherapy before treatment from 4 hospitals (68 in the primary cohort and 34 in the external validation cohort). Quantitative imaging features were extracted from contrast-enhanced fat-suppressed T1-weighted images (CE FS T1WI). Four classification methods, i.e., the least absolute shrinkage and selection operator logistic regression (LASSO-LR), support vector machine (SVM), Gaussian process (GP), and Naive Bayes (NB) algorithm, were compared for feature selection and radiomics signature construction. The predictive performance of the radiomics signatures was assessed with the area under receiver operating characteristics curve (AUC), calibration curve, and decision curve analysis (DCA). Thirteen radiomics features selected based on the LASSO-LR classifier were adopted to construct the radiomics signature, which was significantly associated with the pathologic response. The prediction model achieved the best performance between good and poor responders with an AUC of 0.882 (95% CI, 0.837-0.918) in the primary cohort. Calibration curves showed good agreement. Similarly, findings were validated in the external validation cohort with good performance (AUC, 0.842 [95% CI, 0.793-0.883]) and good calibration. DCA analysis confirmed the clinical utility of the selected radiomics signature. The constructed CE FS T1WI-radiomics signature with excellent performance could provide a potential tool to predict pathologic response to NAC in patients with osteosarcoma. • The radiomics signature based on multicenter contrast-enhanced MRI was useful to predict response to NAC. • The prediction model obtained with the LASSO-LR classifier achieved the best performance. • The baseline clinical characteristics were not associated with response to NAC.

Progressive Desmoid Tumor: Radiomics Compared With Conventional Response Criteria for Predicting Progression During Systemic Therapy-A Multicenter Study by the French Sarcoma Group.

OBJECTIVE. The response of desmoid tumors (DTs) to chemotherapy is evaluated with Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) in daily practice and clinical trials. MRI shows early change in heterogeneity in responding tumors due to a decrease in cellular area and an increase in fibronecrotic content before dimensional response. Heterogeneity can be quantified with radiomics. Our aim was to develop radiomics-based response criteria and to compare their performances with clinical and radiologic response criteria. MATERIALS AND METHODS. Forty-two patients (median age, 38.2 years) were included in this retrospective multicenter study because they presented with progressive DT and had an MRI examination at baseline, which we refer to as "MRI-0," and an early MRI evaluation performed after the first chemotherapy cycle (mean time after first chemotherapy cycle, 3 months [SD, 28 days]), which we refer to as "MRI-1." After signal intensity normalization, voxel size standardization, discretization, and segmentation of DT volume on fat-suppressed contrast-enhanced T1-weighted imaging, 90 baseline and delta 3D radiomics features were extracted. Using cross-validation and least absolute shrinkage and selection operator-penalized Cox regression, a radiomics score was generated. The performances of models based on the radiomics score, modified Response Evaluation Criteria in Solid Tumors, European Association for the Study of the Liver criteria, Cheson criteria, Choi criteria, and revised Choi criteria from MRI-0 to MRI-1 to predict progression-free survival (PFS, as defined by RECIST 1.1) were assessed with the concordance index. The results were adjusted for performance status, tumor volume, prior chemotherapy, current chemotherapy, and β-catenin mutation. RESULTS. There were 10 cases of progression. The radiomics score included four variables. A high score indicated a poor prognosis. The radiomics score independently correlated with PFS (adjusted hazard ratio = 5.60, p = 0.003), and none of the usual response criteria independently correlated with PFS. The prognostic model based on the radiomics score had the highest concordance index (0.84; 95% CI, 0.71-0.96). CONCLUSION. Quantifying early changes in heterogeneity through a dedicated radiomics score could improve response evaluation for patients with DT undergoing chemotherapy.

Myofibroma/myofibromatosis: MDCT and MR imaging findings in 24 patients with radiological-pathological correlation

BackgroundThe aim of this study was to characterize the radiological features of myofibroma on multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) and correlate the imaging findings with pathologic features.MethodsThe radiological findings of 24 patients with 29 myofibromas were retrospectively reviewed. All images were evaluated with emphasis on density, signal intensity, hypointense area, and enhancement, correlating these with pathologic findings.ResultsOn plain MDCT scan, 4(26.7%) tumors were homogeneous isodensity, 4(26.7%) tumors were heterogeneous hyperdensity, and 7(46.7%) tumors were heterogeneous hypodensity. On contrast-enhanced MDCT scan, all tumors (9/9) showed heterogeneous enhancement with moderate in 3(33.3%) and marked in 6(66.7%) tumors, and their enhancements were higher compared to adjacent skeletal muscle (P = 0.0001). On MRI, heterogeneous slight hyperintensity, homogeneous slight hyperintensity, and heterogeneous hypointensity on T1-weighted imaging (T1WI) were observed in 14(82.3%), 1(5.9%) and 2(11.8%) tumors, respectively. On T2-weighted imaging (T2WI) and fat-suppressed (FS) T2WI, all tumors demonstrated heterogeneous hyperintensity. All tumors showed heterogeneous marked enhancement on FS contrast-enhanced T1WI. On T1WI, T2WI, FS T2WI, and FS contrast-enhanced T1WI, irregular strip or/and patchy hypointensities were found in 16(94.1%), 12(100%), 17(100%) and 17(100%) tumors, respectively, and pseudocapsule was seen in 5(29.4%) tumors. The hypointensities and pseudocapsule on MRI were exactly corresponding to pathological interlacing collagen fibers and fibrosis. The age of the recurrent group was lower than that of the non-recurrent group (P = 0.001) and the tumors without pseudocapsule were more likely to recur than those with pseudocapsule (P = 0.034).ConclusionMyofibromas are characterized by heterogeneous density or signal intensity, with moderate or marked enhancement. The hypointensities and pseudocapsule on MRI may be helpful in diagnosis, and the absence of pseudocapsule and younger age may be risk factors for tumor recurrence.

Tumor grade in soft-tissue sarcoma: Prediction with magnetic resonance imaging texture analysis.

To determine the value of 3T magnetic resonance imaging (MRI) texture analysis in differentiating high- from low-grade soft-tissue sarcoma.Forty-two patients with soft-tissue sarcomas who underwent 3T MRI were analyzed. Qualitative and texture analysis were performed on T1-, T2- and fat-suppressed contrast-enhanced (CE) T1-weighted images. Various features of qualitative and texture analysis were compared between high- and low-grade sarcoma. Areas under the receiver operating characteristic curves (AUC) were calculated for texture features. Multivariate logistic regression analysis was used to analyze the value of qualitative and texture analysis.There were 11 low- and 31 high-grade sarcomas. Among qualitative features, signal intensity on T1-weighted images, tumor margin on T2-weighted images, tumor margin on fat-suppressed CE T1-weighted images and peritumoral enhancement were significantly different between high- and low-grade sarcomas. Among texture features, T2 mean, T1 SD, CE T1 skewness, CE T1 mean, CE T1 difference variance and CE T1 contrast were significantly different between high- and low-grade sarcomas. The AUCs of the above texture features were > 0.7: T2 mean, .710 (95% confidence interval [CI] .543–.876); CE T1 mean, .768 (.590–.947); T1 SD, .730 (.554–.906); CE T1 skewness, .751 (.586–.916); CE T1 difference variance, .721 (.536–.907); and CE T1 contrast, .727 (.530–.924). The multivariate logistic regression model of both qualitative and texture features had numerically higher AUC than those of only qualitative or texture features.Texture analysis at 3T MRI may provide additional diagnostic value to the qualitative MRI imaging features for the differentiation of high- and low-grade sarcomas.

Development and external validation of an MRI-based radiomics nomogram for pretreatment prediction for early relapse in osteosarcoma: A retrospective multicenter study

PurposeTo develop and externally validate an MR-based radiomics nomogram from retrospective multicenter datasets for pretreatment prediction of early relapse (≤ 1 year) in osteosarcoma after surgical resection. MethodsThis multicenter study retrospectively enrolled 93 patients (training cohort: 62 patients from four hospitals; validation cohort: 31 patients from two hospitals) with clinicopathologically confirmed osteosarcoma who received neoadjuvant chemotherapy and surgical resection at six hospitals between January 2009 and October 2017. Radiomics features were extracted from contrast-enhanced fat-suppressed T1-weighted (CE FS T1-w) images. Least absolute shrinkage and selection operator (LASSO) regression was applied for feature selection and radiomics signature construction. The radiomics nomogram that incorporated the radiomics signature and subjective MRI-assessed candidate predictors was developed to predict early relapse with a multivariate logistic regression model in the training cohort and validated in the external validation cohort. The performance of the nomogram was assessed by its discrimination, calibration, and clinical usefulness. ResultsThe radiomics signature comprised six selected features and achieved favorable prediction efficacy. The radiomics nomogram incorporating the radiomics signature and subjective MRI-assessed candidate predictors (joint invasion and perivascular involvement) from the multicenter datasets achieved better discrimination in the training cohort (C-index：0.907, 95 % CI: 0.838−0.977) and external validation cohort (C-index: 0.811, 95 % CI: 0.653−0.970), and good calibration. Decision curve analysis suggested that the combined nomogram was clinically useful. ConclusionThe proposed MRI-based radiomics nomogram could provide a non-invasive tool to predict early relapse of osteosarcoma, which has the potential to improve personalized pretreatment management of osteosarcoma.

1706P - Radiomics improves response evaluation for desmoid tumours treated with chemotherapy

BackgroundResponse of desmoid tumors (DT) to chemotherapy (CT) is evaluated according to RECIST criteria in daily practice and clinical trials. However, MRI demonstrates early change in heterogeneity in responding tumor, due to decrease in cellular area and increase in fibro-necrotic content, before dimensional response. Heterogeneity can be quantified through radiomics approach. Aim was to develop radiomics-based response criteria and to compare their performances with usual criteria. Methods43 patients (28 women, median age: 38.2) were prospectively included in this ancillary multicentre study of a randomized phase II trial (NCT01876082) as they presented with progressive DT, contrast-enhanced MRI at baseline (MRI-0) and early evaluation (3 months later, MRI-1). After signal intensities normalization, voxel size standardization and segmentation of whole DT volume on fat-suppressed contrast-enhanced T1-weighted imaging, 90 baseline and delta 3D-radiomics features (RF) were extracted. Using least absolute shrinkage and selection operator with Cox regression model and cross validation, a radiomics score based on selected and weighted RF was generated. The performances of prognostic models based on radiomics score, RECIST, mRECIST, EASL, Cheson, Choi and modified-Choi criteria from MRI-0 to MRI-1 to predict progression-free survival (PFS) were assessed with concordance-index. All the results were adjusted for ECOG performance status, initial tumor volume, prior CTs, current CT and B-catenin mutation. Usual response criteria were evaluated in both disease control and objective response settings. ResultsThere were 11 progressions. The radiomics score included 4 variables (1 baseline RF and 3 delta-RF). A high radiomics score indicated a poorer prognosis. The radiomics score significantly correlated with PFS (adjusted hazard ratio = 3.39, 95%CI=[1.47-7.79], p=0.0043) while none of the usual response criteria was (range of p-values=[0.166-0.750]). The prognostic model based on radiomics score had the highest concordance-index (0.794, 95%CI=[0.678-0.910]). ConclusionsQuantifying heterogeneity with MRI at baseline and its early change through a dedicated radiomics score can improve the response evaluation for DT treated with CT. Legal entity responsible for the studyAntoine Italiano. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Development and External Validation of an MRI-Based Radiomics Nomogram for Pretreatment Prediction for Early Relapse in Osteosarcoma: A Retrospective Multicenter Study

Background: To develop and externally validate an MR-based radiomics nomogram from retrospective multicenter datasets for pretreatment prediction of early relapse (≤1 year) in osteosarcoma after surgical resection. Methods: This multicenter study retrospectively enrolled 93 patients (training cohort: 62 patients from four hospitals; validation cohort: 31 patients from two hospitals) with clinicopathologically confirmed osteosarcoma who received neoadjuvant chemotherapy and surgical resection at six hospitals between January 2009 and October 2017. Radiomics feature was extracted from contrast-enhanced fat-suppressed T1-weighted (CE FS T1-w) images. A radiomics signature was constructed with least absolute shrinkage and selection operator (LASSO) regression. The radiomics nomogram that incorporated the radiomics signature and subjective MRI-assessed risk factors was developed to predict early relapse with a multivariate logistic regression model in the training cohort and validated in the external validation cohort. The performance of the nomogram was assessed by its discrimination, calibration, and clinical usefulness. Findings: The radiomics nomogram, which incorporated a radiomics signature (consisted of six selected features) and subjective MRI-assessed risk factors (joint invasion and perivascular involvement) from the multicenter datasets, achieved good discrimination in the training cohort (C-index: 0.907, 95% CI: 0.838-0.977) and external validation cohort (C-index: 0.811, 95% CI: 0.653-0.970), and good calibration. Decision curve analysis suggested that the combined nomogram was clinically useful. Interpretation: The proposed MRI-based radiomics nomogram could provide a nonvasive tool to develop a model for pretreatment prediction of early relapse in osteosarcoma, which has potential to lead to improvement of personalized pretreatment management of osteosarcoma. Funding: This research is supported by the National Key Research and Development Program of China (No. 2017YFC1309100), the National Natural Science Foundation of China (Grant Nos. 81871510, 81771912). Declaration of Interest: No competing interest exists. Ethical Approval: This multicentric study was approved by the ethics committee of every participating hospital and was conducted in accordance with the Declaration of Helsinki.

Background parenchymal enhancement assessment: Inter- and intra-rater reliability across breast MRI sequences

ObjectiveTo evaluate inter- and intra-rater reliability of background parenchymal enhancement (BPE) assessment across breast MRI sequences. Materials and methodsInstitutional review board approval was obtained and the requirement for consent was waived. Three radiologists qualitatively categorized BPE on 150 breast MRI using a four-point scale (minimal, mild, moderate or marked) according to BI-RADS category system. According to MR-sequence used for the assessment of BPE, inter-rater and intra-rater reliability across a simulated reading strategy with four options was performed: (1) initial contrast-enhanced (CE) fat-suppressed T1-weighted images (2) initial CE subtracted images (3) maximum-intensity-projection (MIP) of the first CE subtracted images (4) combination of initial CE fat-suppressed T1-weighted, initial CE subtracted and MIP images. Raters repeated BPE assessment of 45 breast MRI four weeks after the initial assessment. Gwet’s AC1 index with ordinal weights was used to assess reliabilities. ResultsGwet’s index for the reliability among the three raters was 0.68 (0.63-0.74) using initial contrast-enhanced fat-suppressed T1 weighted images, 0.74 (0.69-0.80) using subtracted images, 0.80 (0.76-0.83) using MIP, 0.80 (0.77-0.84) using a combination of the initial contrast-enhanced fat-suppressed T1 weighted, initial contrast-enhanced subtracted and MIP images. Test-retest reliability was 0.81 (0.60–1.00) for rater 1, 0.77 (0.55-0.98) for rater 2, 0.79 (0.59-0.99) for rater 3 using the combination of initial contrast-enhanced fat-suppressed T1 weighted, initial contrast-enhanced subtracted and MIP images. ConclusionsOverall, the combination of all CE MRI images showed the highest reliability of BPE assessment. However, MIP showed a high reliability with lower reading time compared to the combination of all CE MRI images.

Background Parenchymal Enhancement and Fibroglandular Tissue Proportion on Breast MRI: Correlation with Hormone Receptor Expression and Molecular Subtypes of Breast Cancer.

To assess the relationship between background parenchymal enhancement (BPE) and fibroglandular tissue (FGT) proportion on breast magnetic resonance imaging (MRI) and hormone receptor expression and molecular subtypes in invasive breast cancer. This retrospective study enrolled 75 breast cancer patients who underwent breast MRI before treatment. T1-weighted images were reviewed to determine the FGT proportion, and contrast-enhanced fat-suppressed T1-weighted images were reviewed to determine BPE. Estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2-neu (HER2) status, and molecular subtypes of the tumors were compared with the BPE and FGT proportions. Women with high BPE tended to have increased rate of ER and PR positive tumors (p=0.018 and p=0.013). FGT proportion was associated with ER positivity (p=0.009), but no significant differences between FGT proportion and PR positivity were found (p=0.256). There was no significant difference between HER2 status and any of the imaging features (p=0.453 and p=0.922). For premenopausal women, both FGT proportion and BPE were associated with molecular subtypes (p=0.025 and p=0.042). FGT proportion was also associated with BPE (p<0.001). In women with invasive breast cancer, both high FGT containing breasts and high BPE breasts tended to have ER positive tumors.

Comparison of image quality between conventional VIBE and radial VIBE in free-breathing paediatric abdominal MRI

To compare the image quality between conventional volume interpolated breath-hold examination (VIBE) and radial VIBE in contrast-enhanced fat-suppressed T1-weighted images of paediatric abdominal magnetic resonance imaging (MRI) during free-breathing. Images from paediatric patients who underwent contrast-enhanced abdominal MRI with a 3T magnet using conventional VIBE (conventional group) and radial VIBE (radial group) while freely breathing were reviewed retrospectively. For objective analysis, the mean values of noise and signal-to-noise ratio (SNR) in the liver on contrast-enhanced fat-suppressed T1-weighted images were compared. For subjective analysis, overall image quality, respiratory motion, portal vein clarity, and hepatic margin sharpness were assessed using four-point scales. Nine patients (mean age of 2.8±2.3 years) in the conventional and 17 patients (mean age of 2.4±2.8 years) in the radial groups were included. According to the objective analysis, the noise was significantly lower and the SNR was significantly higher in the radial group than those in the conventional group (all, p<0.001). In the subjective analysis, overall image quality, respiratory motion, portal vein clarity, and hepatic margin sharpness were all significantly higher in the radial group (all, p<0.001). Paediatric abdominal MRI images with radial VIBE showed lower noise with higher SNR in objective analysis and higher image quality in subjective analysis, compared to conventional VIBE.

Duplication of chromosome segment 12q13-15 in a lipomatous tumor with minimal nuclear atypia: A case report.

Ordinary lipoma is cytogenetically characterized by structural rearrangements, particularly translocations, of 12q13-15. By contrast, atypical lipomatous tumors exhibit supernumerary ring or giant marker chromosomes that are composed mainly of amplified material from the 12q13-15 chromosome segment. The present study describes the cytogenetic and molecular cytogenetic findings from a lipomatous tumor with minimal nuclear atypia that was identified in a 49-year-old female patient. Magnetic resonance imaging of the right shoulder revealed a 13-cm fatty mass in the subcutaneous layer that possessed only pencil-line septa. Contrast-enhanced fat-suppressed T1-weighted images demonstrated faint enhancement. A marginal excision was performed. Histologically, the tumor was composed of lobules that consisted of mature adipocytes separated by thin fibrous septa. There was minimal nuclear atypia in certain cells, and a small number of binucleated cells were also observed within the tumor. Immunohistochemically, the tumor cells did not reveal the expression of murine double-minute 2 (MDM2). Cytogenetic analysis revealed a complex karyotype with several numerical and structural alterations, including 12q rearrangements. Spectral karyotyping demonstrated a duplication of chromosome segment 12q13-15. Interphase fluorescence in situ hybridization analysis revealed no MDM2 gene amplification. The present case indicates that duplication of 12q may be associated with minimal nuclear atypia in a subset of lipomatous tumors.

Superior Cervical Sympathetic Ganglion: Normal Imaging Appearance on 3T-MRI.

ObjectiveTo identify superior cervical sympathetic ganglion (SCSG) and describe their characteristic MR appearance using 3T-MRI.Materials and MethodsIn this prospective study, we recruited 53 consecutive patients without history of head and neck irradiation. Using anatomic location based on literature review, both sides of the neck were evaluated to identify SCSGs in consensus. SCSGs were divided into definite (medial to internal carotid artery [ICA] and lateral to longus capitis muscle [LCM]) and probable SCSGs based on relative location to ICA and LCM. Two readers evaluated signal characteristics including intraganglionic hypointensity of all SCSGs and relative location of probable SCSGs. Interrater and intrarater agreements were quantified using unweighted kappa.ResultsNinety-one neck sites in 53 patients were evaluated after exclusion of 15 neck sites with pathology. Definite SCSGs were identified at 66 (73%) sites, and probable SCSGs were found in 25 (27%). Probable SCSGs were located anterior to LCM in 16 (18%), lateral to ICA in 6 (7%), and posterior to ICA in 3 (3%). Intraganglionic hypointensity was identified in 82 (90%) on contrast-enhanced fat-suppressed T1-weighted images. There was no statistical difference in the relative location between definite and probable SCSGs of the right and left sides with intragnalionic hypointensity on difference pulse sequences. Interrater and intrarater agreements on the location and intraganglionic hypointensity were excellent (κ-value, 0.749–1.000).Conclusion3T-MRI identified definite SCSGs at 73% of neck sites and varied location of the remaining SCSGs. Intraganglionic hypointensity was a characteristic feature of SCSGs.

Calcifying aponeurotic fibroma of the finger in an elderly patient: CT and MRI findings with pathologic correlation.

Calcifying aponeurotic fibroma (CAF) is a rare, locally aggressive fibroblastic lesion that occurs predominantly in the distal extremities of children and adolescents. In the present study, a case of pathologically proven CAF arising in the right little finger of a 69-year-old woman is presented. Physical examination revealed a firm, immobile, non-tender mass. Plain radiographs showed a faintly calcified soft tissue mass without bone involvement and computed tomography scans clearly demonstrated the presence of the lesion. Magnetic resonance imaging revealed that the lesion exhibited low to intermediate signal intensity on T1-weighted images and heterogeneous high signal intensity with small foci of low signal intensity on T2-weighted spectral presaturation with inversion recovery images. Contrast-enhanced fat-suppressed T1-weighted images demonstrated intense heterogeneous enhancement throughout the mass. The patient underwent an excisional biopsy. Histologically, the tumor showed a biphasic pattern, composed of a moderately cellular fibromatosis-like component and irregular calcified areas with polygonal epithelioid cells. There has been no evidence of local recurrence four months following surgery. To the best of our knowledge, this case report describes the oldest patient with this condition.

Imaging features of periosteal chondroma manifesting as a subcutaneous mass in the index finger.

Periosteal chondroma is a rare benign hyaline cartilage neoplasm that occurs most commonly in the metaphases of long tubular bones. We present a unique case of periosteal chondroma arising in the proximal phalanx of the left index finger in a 12-year-old boy. Physical examination revealed a slightly protuberant, subcutaneous mass. Plain radiographs and computed tomography scans showed a periosteal lesion producing saucerization of the cortex and subjacent cortical sclerosis, without internal matrix calcification. On magnetic resonance imaging, the lesion exhibited intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Contrast-enhanced fat-suppressed T1-weighted images demonstrated peripheral and septal enhancement. The patient underwent a marginal excision with curettage of the underlying bone cortex. Histological examination confirmed the diagnosis of periosteal chondroma. There has been no evidence of local recurrence eight months after surgery. Periosteal chondroma can protrude into the subcutaneous soft tissue causing a palpable mass. Recognition of the typical radiological features can lead to an accurate diagnosis of this rare condition.

Experimental Study of Artificially Induced Intramuscular Gossypiboma in Rabbits: Correlation of Sequential MRI Findings With Pathologic Findings

The purpose of this study was to evaluate the sequential MRI findings of intramuscular gossypiboma and to correlate them with the pathologic findings in rabbits. Sterile gauze was packed in the hamstring muscles of 12 rabbits, and sequential MR images were obtained 1, 2, and 4 weeks and 2, 6, and 12 months after gauze insertion. Two rabbits were sacrificed at each time point. Their pathologic findings were compared with the MRI findings on each date. At the acute stage, the gossypibomas appeared as areas of heterogeneous low signal intensity on T2-weighted MR images with inflammatory change around the gossypiboma. In the subacute stage, the gossypibomas appeared as areas of peripheral low and central high signal intensity with wavy stripes of low signal intensity on T2-weighted images. On contrast-enhanced fat-suppressed T1-weighted images, the peripheral enhancement of the masses advanced toward the center of the mass as the fibrocollagenization between the gauze bundles progressed centrally. In the chronic stage, on contrast-enhanced fat-suppressed T1-weighted images, central advancement of the peripheral enhancement occurred according to the maturation of the fibrocollagenization. Calcifications around individual gauze fibers were observed 6-12 months after gauze insertion. On sequential contrast-enhanced fat-suppressed T1-weighted images of rabbits, intramuscular gossypiboma exhibited a chronologic centripetal enhancement pattern for 1 year mainly owing to concentric progression of fibrocollagenization between gauze bundles toward the center of the mass.

Characteristic magnetic resonance features of focal autoimmune pancreatitis useful for differentiation from pancreatic cancer

To identify characteristic magnetic resonance (MR) features of focal autoimmune pancreatitis (f-AIP) useful for differentiation from pancreatic cancer (PC). We retrospectively analyzed MR imaging findings of 20 f-AIP lesions and 40 PC lesions smaller than 40 mm in diameter. On fat-suppressed T2-weighted images and dynamic contrast-enhanced fat-suppressed T1-weighted images (DCE-T1WI), we classified MR features of internal signal intensity for each lesion into homogeneous, speckled, or target type. We assessed the sensitivity, specificity, and accuracy of these findings in the diagnosis of f-AIP. We also investigated the incidence of previously reported findings for differentiation between f-AIP and PC. Speckled enhancement within a hypointense or isointense lesion on pancreatic phase DCE-T1WI (speckled type) was observed more frequently in f-AIP than in PC, with high sensitivity, high specificity, and high accuracy. Hypointensity to hyperintensity surrounding a less enhanced focal area on DCE-T1WIs (target type) and upper stream main pancreatic duct dilatation were observed more frequently in PC than in f-AIP. Speckled enhancement inside an f-AIP lesion on pancreatic phase DCE-T1WI was useful for differentiation from PC.

Retroportal main pancreatic duct with circumportal pancreas: radiographic visualization

Purpose The aim of this study was to investigate the imaging findings of retroportal main pancreatic duct (RMPD), a rare anomaly of the pancreas, and circumportal pancreas (CP) on computed tomography (CT) and magnetic resonance (MR) imaging. We also reviewed the previous literature and discussed its best imaging method, etiology and clinical importance. Methods This work is a retrospective study. Two cases of RMPD were enrolled. The imaging findings of RMPD and CP were reviewed among the various CT and MR images obtained. Differences in visualization among the scans were evaluated using a four-stage model. Results RMPD was always accompanied by CP. RMPD was detectable on contrast-enhanced CT but not on noncontrasted CT. RMPD was shown most clearly on arterial, portal and late phases of contrast-enhanced CT, contrast-enhanced fat-suppressed T1-weighted images and fat-suppressed T2-weighted images. CP was much easier to detect than RMPD and could be identified even on noncontrasted images. Conclusions We described the fourth and the fifth reported cases of RMPD. This is the first study to describe its MR imaging findings. CP was always present in cases of RMPD and was easily detectable on tomographic images. When radiologists or surgeons notice CP, it is necessary to pay attention to the course of the main pancreatic duct, particularly preoperatively to avoid surgical complications. It should be noted that these anomalies are undetectable on projection images.

Female External Genitalia and Urethra on MR Imaging: Optimal Pulse Sequence and Comparison of Anatomy in Premenopausal and Postmenopausal Women

Purpose : To describe normal anatomy and compare the differences of external genital organs and urethra on MR imaging in pre- and postmenopausal women. Materials and Methods : A total of 19 pre- and 18 postmenopausal healthy women underwent pelvis MR imaging at 1.5 T. Two radiologists retrospectively scored and compared the image quality of female external genitalia and urethra on axial T2-weighted images (T2WI) and axial fat-suppressed contrast-enhanced T1-weighted images (FSCE-T1WI) by using Wilcoxon signed ranks test. The radiologists compared the wall thickness or size of external genital organs and urethra on FSCE-T1WI between two groups by using Student t test. Results : Image quality was better with FSCE-T1WI than with T2WI in all subjects (p