Showed Rim Enhancement Research Articles

A Case of Hepatic Epithelioid Hemangioendothelioma Treated with Radiofrequency Ablation

Epithelioid hemangioendothelioma is a rare, low to intermediate grade malignant vascular tumor. A 62-year-old woman visited our hospital with abdominal discomfort for 3 months. Abdominal ultrasound showed two homogeneous hypoechoic nodules with well-defined margin. Contrast-enhanced ultrasound showed rim enhancement in arterial phase and early and marked washout in portal phase. We decided to perform liver biopsy for histological confirmation. The lesions were diagnosed as hepatic epithelioid hemangioendothelioma. She was successfully treated with radiofrequency ablation.

Preoperative MRI of breast squamous cell carcinoma: diagnostic value of distinguishing between two subtypes

To retrospectively analyse the clinical and MRI data of primary squamous cell carcinoma (SCC), particularly pure squamous cell carcinoma (PSCC) and mixed squamous cell carcinoma (MSCC). The MRI data and clinicopathological characteristics of 20 patients with histopathologically confirmed SCC of the breast, including eight PSCC patients and 12 MSCC patients, from multiple centres between January 2013 and December 2020 were analysed retrospectively. Nine of 12 patients in the MSCC group showed hyperintensity on T1-weighted imaging (WI), while this feature was not observed in the PSCC group (p=0.001). Most of the PSCC group showed rim enhancement, whereas most of the MSCC group showed heterogeneous enhancement (p=0.007). In addition, there was no significant difference in the thickness of the rim enhancement and the percentage of necrotic components in the tumours between the two types of SCCs of the breast (p=0.545 and p=0.662, respectively). Four patients (4/12) in the MSCC group had sentinel lymph node metastasis, while only one patient (1/8) in the PSCC group showed lymph node metastasis (p=0.603). Metastatic disease occurred in 25% of patients with PSCC and in approximately 41.7% of patients with MSCC. The signal on T1WI and internal enhancement characteristics were the key features for differentiating PSCC and MSCC. Therefore, MRI phenotypes may provide additional information for the pathological classification of breast SCC.

Conventional and advanced MR imaging findings in a cohort of pathology-proven dermoid cysts of the pediatric scalp and skull.

In the pediatric population, dermoid cysts are among the most frequent lesions of the scalp and skull. Imaging plays a key role in characterizing scalp and skull lesions in order to narrow the differential diagnoses. In general, dermoids are described as heterogeneous T1-/T2-hypo- to hyperintense lesions on magnetic resonance imaging. The goal of this retrospective study is to evaluate the diffusion weighted imaging findings while reviewing the conventional T1-/T2-/T1+C-weighted MR characteristics in a pathology-proven series of 14 dermoids of the pediatric scalp and skull. In our pediatric cohort (eight boys, six girls, age range 3-95 months), half of the dermoids were homogeneous T1-hypointense and homogeneous T2-hyperintense. We found a mixture of restricted (45.5%) and increased diffusion (54.5%) in dermoids. The vast majority of dermoids (91.7%) showed rim enhancement. Most dermoids (57.1%) were located at the midline and adjacent to one of its sutures. This study suggests that dermoids may have more variable imaging appearances than hitherto assumed and are frequently seen in close proximity or adjacent to the anterior fontanelle.

Clinical Features and Prognostic Factors of Pediatric Glioblastoma: Report of 38 Cases

To better characterize children with glioblastoma, assess outcomes, and identify prognostic factors associated with overall survival and progression-free survival in a relatively large cohort from a single institution. For this retrospective review, 38 pediatric patients with a diagnosis of glioblastoma who were treated at The First Affiliated Hospital of Zhengzhou University between January 2015 and January 2020 were selected. Clinical and pathological characteristics, imaging, treatment, and survival variables were compared. There were 24 boys and 14 girls with a median age of 11.5 years (range, 3-18 years). All patients underwent surgery, with gross total resection in 16 and subtotal resection in 22. Of patients, 18 received radiation combined with chemotherapy, 6 received radiation or chemotherapy alone, and 14 did not receive any adjuvant therapy. Contrast-enhanced magnetic resonance imaging of 21 patients showed rim enhancement, while heterogeneous enhancement was shown on imaging of the other 17 patients. Tumors were observed in hemispheric locations in 19 cases and in central locations in the others. Median overall survival was 10.5 months with a median progression-free survival of 6 months. Extent of resection, adjuvant therapy, and original site of tumor were identified as independent predictors for progression-free survival and overall survival on multivariate analysis. There were significant differences in prognosis among different enhancement characteristics; patients with rim-enhancing tumors had a better prognosis. Pediatric glioblastoma carries a dismal prognosis. Maximum safe resection followed by adjuvant radiation with chemotherapy is considered standard treatment. Better outcomes are associated with hemispheric tumor locations and rim enhancement on magnetic resonance imaging.

Intraoperative Use of Indocyanine Green Fluorescence in Hepatobiliary and Pancreatic Cancer Resections: Current State and Considerations

Introduction: Surgery for hepatobiliary and pancreatic malignancies often has unfavourable outcomes due to incomplete resection, with positive histopathological margins and locoregional metastases. Intraoperative use of indocyanine green fluorescence (ICG) with near-red infrared light can improve tumor detectability and achieve R0 status. Methods: Review of current literature. Results: ICG fluorescence and bile excretion allows for real-time visualisation of malignant tissues and assessment of resection margins. In liver surgery it can identify subcapsular lesions, a property especially useful in minimally invasive surgery where there is loss of tactile feedback and direct visual inspection. It can also delineate hepatic segmental anatomy for anatomical resections. Hepatocellular carcinomas tend to uniformly uptake ICG, whereas primary or metastatic adenocarcinomas like cholangiocarcinomas and colorectal liver metastases as well as poorly differentiated hepatocellular carcinomas show rim enhancement. In pancreatic cancer, fluorescence of the resection margin has been shown to correspond to presence of malignancy on histopathological assessement. ICG can also help to detect micrometastases and extrahepatic spread and distinguish between scar tissue and disease following neoadjuvant chemoradiotherapy. However the technique has limitations: wide variability of method and dose of administration, no visualisation of deep seated lesions, high background fluorescence, false positives up to 40% requiring additional verification by other modalities like intraoperative ultrasound or frozen section for newly detected lesions. Conclusion: ICG fluorescence can offer increased detectability of malignancy and improve post-operative outcomes in hepatobiliary and pancreatic resections. However there are limitations such as superficial depth of detection and low specificity which need improvement to achieve maximum benefit.

Can MRI Biomarkers Predict Triple-Negative Breast Cancer?

The purpose of this study was to investigate MRI features of triple-negative breast cancer (TNBC) compared with non-TNBC, to predict histopathological results. In the study, 26 patients with TNBC and 24 with non-TNBC who underwent multiparametric MRI of the breast on a 3 T magnet over a 10-months period were retrospectively recruited. MR imaging sets were evaluated by two experienced breast radiologists in consensus and classified according to the 2013 American College of Radiology (ACR) BI-RADS lexicon. The comparison between the two groups was performed using the Chi-square test and followed by logistic regression analyses. We found that 92% of tumors presented as mass enhancements (p = 0.192). 41.7% of TNBC and 86.4% of non-TNBC had irregular shape (p = 0.005); 58.3% of TNBC showed circumscribed margins, compared to 9.1% of non-TNBC masses (p = 0.001); 75% of TNBC and 9.1% of non-TNBC showed rim enhancement (p < 0.001). Intralesional necrosis was significantly associated with TNBC (p = 0.016). Rim enhancement and intralesional necrosis risulted to be positive predictors at univariate analysis (OR = 29.86, and 8.10, respectively) and the multivariate analysis confirmed that rim enhancement is independently associated with TNBC (OR = 33.08). The mean ADC values were significantly higher for TNBC (p = 0.011). In conclusion, TNBC is associated with specific MRI features that can be possible predictors of pathological results, with a consequent prognostic value.

Clinical and Imaging Features of Primary Cardiac Angiosarcoma.

This study aims to explore computed tomography (CT) and magnetic resonance imaging (MRI) features of patients diagnosed with primary cardiac angiosarcoma. The study involved the analysis of 12 patients diagnosed with primary cardiac angiosarcoma who underwent non-contrast (8/12) or contrast-enhanced CT (10/12) or MRI (4/12). Imaging appearances, including the tumor location and adjacent infiltration, were analyzed. All 12 lesions were located in the right atrium with a broad base. Adjacent invasion including the tricuspid valve and right ventricle (2/12), inferior or superior vena cava (2/12), pericardium (10/12), and right coronary artery (7/12) was common. On unenhanced CT scans, tumors in two patients were homogeneous in density, whereas the others were inhomogeneous. Ten patients showed heterogeneous enhancement. The enhancement pattern showed no direct correlation with the differentiation degree of the tumor. Four lesions manifested as heterogeneous intensity, with hyperintense hemorrhage foci on both T1- and T2-weighted MRI. Three showed rim enhancement and one showed patchy enhancement. Primary cardiac angiosarcoma often involves the right side of the heart with infiltration of peripheral structures. CT features include typical inhomogeneous density on unenhanced scans and heterogeneous centripetal enhancement on enhanced scans. A cauliflower-like appearance on both T1- and T2-weighted MRI is common. The characteristic enhancement pattern of MRI remains to be determined.

3D-Double-Inversion recovery detects perilesional gliosis better than 3D-FLAIR and postcontrast T1 imaging in calcified neurocysticercosis.

Perilesional gliosis is an important substrate for seizures in patients harboring a calcified neurocysticercosis (NCC) lesion and magnetic resonance imaging (MRI) is useful for evaluating gliosis. The purpose of this study was to evaluate the usefulness of double-inversion recovery (DIR) sequence for identifying perilesional gliosis. Hospital-based cross-sectional study. Forty-five patients with seizures were included in this study and a total of 88 calcified lesions identified on susceptibility weighted imaging (SWI) were evaluated on 3D-fluid attenuating inversion recovery (FLAIR), 3D-DIR, and 3D-postcontrast T1-weighted imaging on a 3T MRI for the presence of perilesional signal changes/enhancement. Perilesional signal was rated on a semiquantitative scale from grade 0 to 2 by independent raters. Friedman, Wilcoxon signed rank, and Kappa tests were used. 3D-DIR sequence performed better than both 3D-FLAIR and postcontrast 3D-T1W sequences as more number of lesions showed perilesional signal change on DIR sequence. DIR sequence showed perilesional signal abnormality in 24 lesions in which 3D-FLAIR was normal, whereas in another 18 lesions, it demonstrated perilesional signal changes better than 3D-FLAIR. In only three lesions, FLAIR was found to be superior to DIR sequence, whereas postcontrast T1W images showed rim enhancement in five cases where no perilesional signal change was seen on FLAIR/DIR sequences. Combining 3D-DIR with 3D-FLAIR, and postcontrast 3D-T1W sequences is beneficial for evaluation of calcified NCC lesions and 3D-DIR sequence is better than other two sequences for perilesional signal abnormalities.

Chest CT Findings of Primary Neuroendocrine Tumor of Thymus:Analysis of 7 Cases

Objective To explore the clinical features of primary neuroendocrine tumor of thymus (pNET) on computed tomography (CT). <b>Method</b> CT findings and clinical features of 7 patients with pathologically confirmed primary pNET were retrospectively analyzed. Results There were 2 male and 5 female patients aged (52.1±13.3) years,without accompanying endocrine symptoms. Three patients had low-and intermediate-grade pNET and 4 had high-grade pNET. CT showed solid masses in the anterior mediastinum with heterogeneous density,and the average maximum diameter was 6.6 cm. Five patients had necrosis and 4 patients had calcification. After contrast administration,5 cases showed flower ring-like enhancement and 2 cases showed rim enhancement. All lesions showed invasive features,including vessel encompassment (n=5),involvement of surrounding fat space (n=4),involvement of the pleura (n=3),involvement of pericardium (n=2),involvement of chest wall (n=1),direct lung involvement (n=2),lymphadenopathy (n=1),and primary renal neuroendocrine tumor with lung metastasis (n=1). Conclusion pNET is mainly seen in middle-aged people. The typical characteristics of pNET on CT include large mass,calcification,necrosis,and flower ring-like enhancement. CT can clearly display the pNET and the involvement of its surrounding tissues and therefore is helpful for preoperative diagnosis and WHO classification of pNET.

Comparative study of the diagnostic value of ultrasonography and MRI in mucinous adenocarcinoma of breast

Objective To investigate ultrasonographic and magnetic resonance imaging features of pure mucinous adenocarcinoma of breast, and to discuss the diagnose value. Methods Eighty-eight patients with 92 breast lesions of pure mucinous adenocarcinoma had undergone ultrasonography and MRI. The imaging features were reviewed and the diagnostic values were compared between the two imaging examinations. Results On ultrasonography, tumors were mostly showed well-defined margins (77.2%), lobulated shape (60.9%), hypoechoic (51.1%), heterogeneous texture (63.0%), posterior echo enhancement (82.6%). Color Doppler imaging showed vascularity in 75% of these lesions.On magnetic resonance imaging, most tumors showed circumscribed mass with lobulated shape. Sixty-four lesions (69.6%) showed hypointensity on T1-wighted images.Hyperintensity and strongly hyperintensity on T2-weighted images were identified in 71 cases and 21 cases, respectively. After contrast, 54 cases showed rim enhancement and the other 38 cases showed heterogeneous enhancement. There was no significant difference in diagnostic accuracy between ultrasonography and MRI (72.8% vs 77.2%, P=0.481). Combined the two imaging examinations, the diagnostic accuracy was higher than that of ultrasonography (84.8% vs 72.8%, P=0.001) and MRI (84.8% vs 77.2%, P=0.016). Conclusions Pure mucinous adenocarcinoma of breast has some typical characteristics in ultrasonography and MRI, combination of the two imaging examinations can improve the diagnostic accuracy. Key words: Ultrasonography; Breast neoplasms; Adenocarcinoma, mucinous; Magnetic resonance imaging

Optimal Phase of Dynamic Computed Tomography for Reliable Size Measurement of Metastatic Neuroendocrine Tumors of the Liver: Comparison between Pre- and Post-Contrast Phases.

ObjectiveThe reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans.Materials and MethodsThe study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations.ResultsOf the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (−6.1–5.7 mm), followed by PVP (−7.9–7.1 mm) and AP (−8.5–7.4 mm) images. Intra-observer agreement showed the same trend: −2.8–2.9 mm and −2.9–2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, −2.8–2.9 mm and −3.0–3.2 mm, respectively, on PVP, and −3.2–4.2 mm and −3.4–3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images.ConclusionThere was better inter- and intra-observer agreement in size measurements of NET liver metastases on precontrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.

Radiologic and histologic features of the T2 hyperintensity rim of meningiomas on magnetic resonance images.

A hyperintensity rim is often seen at the brain-tumor interface of meningiomas upon T2-weighted (T2WI) magnetic resonance imaging (MRI), and it is referred to as the cerebrospinal fluid (CSF) space; however, the true nature of the rim remains unclear. We surveyed the MRI findings and the histopathologic characteristics of such rims. Our study population consisted of 53 consecutive patients who underwent meningioma removal at our hospital. The intensity of the rim on MRI scans obtained with different imaging sequences was assessed in all patients. We used 22 tumors for histopathologic investigation: tissue samples were acquired from both the tumor surface and from a deep intratumoral site. Of the 53 meningiomas, 37 (69.8%) manifested a hyperintensity rim on T2WI (T2-rim). The other 16 showed neither a hyperintense nor a hypointense rim on their T2WI. An enhancement effect corresponding to the rim was observed in 28 of the 37 (75.7%) T2-rim positive tumors. While 9 among the 37 tumors with a T2-rim (24.3%) did not show rim enhancement, they showed low intensity on fluid-attenuated inversion recovery (FLAIR) images. The microvascular density in the tumor capsule was significantly greater in the 12 T2-rim and rim enhancement positive tumors than in 10 tumors that were T2-rim negative or T2-rim positive, but rim enhancement-negative ( p < 0.001, Mann-Whitney U test). We found that 75.7% of T2 hyperintense rims that were detected at the brain-meningioma interface reflected a microvascular-rich capsule layer, rather than the CSF space.

Magnetic resonance imaging appearance of oxidized regenerated cellulose in breast cancer surgery.

To describe magnetic resonance imaging (MRI) findings in patients who underwent breast-conserving surgery followed by oxidized regenerated cellulose (ORC) implantation in surgical cavity. We retrospectively reviewed 51 MRI examinations performed between January 2009 and January 2014 in 51 patients who underwent BCS with ORC implantation. In 29/51 (57%) cases, MRIs showed abnormal findings with three main MRI patterns: (1) complex masses: hyperintense collections on T2-weighted (w) images with internal round hypointense nodules without contrast enhancement (55%); (2) completely hyperintense collections (17%); and (3) completely hypointense lesions (28%). All lesions showed rim enhancement on T1w images obtained in the late phase of the dynamic study with a type 1 curve. Diffusion-weighted imaging was negative in all MRIs and, in particular, 22/29 (76%) lesions were hyperintense but showing ADC values >1.4×10(-3) mm(2)/s, while the remaining 7/29 (24%) lesions were hypointense. In four cases, linear non-mass-like enhancement was detected at the periphery of surgical cavity; these patients were addressed to a short-term follow-up, and the subsequent examinations showed the resolution of these findings. When applied to surgical residual cavity, ORC can lead alterations in surgical scar. This could induce radiologists to misinterpret ultrasonographic and mammographic findings, addressing patients to MRI or biopsy; so knowledge of MRI specific features of ORC, it is essential to avoid misdiagnosis of recurrence.

Use of BI-RADS-MRI descriptors for differentiation between mucinous carcinoma and fibroadenoma

ObjectiveWe evaluated the latest breast imaging reporting and data system (BI-RADS) magnetic resonance imaging (MRI) (5th edition) descriptors and non BI-RADS MRI factors that contribute to differentiation between mucinous carcinomas (MCs) and fibroadenomas (FAs). Materials and methodsThis retrospective study included 27 patients with P-MCs or M-MCs similar to P-MCs and 22 patients with FAs who underwent breast MRI between October 2008 and July 2014 at our institution. Definitive histopathological diagnoses were made for all of the MCs and FAs. The latest BI-RADS MRI descriptors for abnormal enhancement, including maximum diameter, shape (irregular or round/oval), margin (irregular or circumscribed), rim enhancement (present or absent), dark internal septation (absent or present), delayed internal enhancement (heterogeneous or homogeneous), and the time–intensity curve pattern (not persistent or persistent) were evaluated. As additional non BI-RADS MRI factors related to differentiation between MC and FA, age, signal intensity in the T2-weighted image (high or not high), extent of lobulation (strong or weak), enhancing internal septation (present or absent), and the apparent diffusion coefficient value were also evaluated. One radiologist retrospectively evaluated interpreted MR findings and analyzed the findings. Statistically significant findings were identified through univariate and multivariate analyses. Then, three blinded radiologists reviewed the MR images where MR findings had shown a significant association with outcomes during univariate analyses. Independently, the three blinded readers reviewed the MR images for the evaluation of inter-observer variability, and then arrived at a consensus for the evaluation of observer performance. Observer performance and inter-observer variability were determined via a receiver-operating-characteristic curve analysis and weighted k statistics. The sensitivity, specificity, and accuracy of each of the MR findings were calculated. ResultsUnivariate analyses showed that irregular margins were observed more frequently in MCs than in FAs (11/27, 41% vs. 1/22, 0.5%, p<0.05). MCs also showed rim enhancement, delayed heterogeneous enhancement, and enhancing internal septation more frequently than FAs (p<0.05). FAs showed circumscribed margins more frequently than MCs (21/22, 95% vs. 16/27, 59%, p<0.05). FAs also showed dark internal septation more frequently than MCs (18/22, 82% vs. 3/27, 11%, p<0.05). In multivariate analyses, the most significant feature in lesion characterization was delayed heterogeneous enhancement. In the blinded reading, a combination of irregular margin and delayed heterogeneous enhancement showed the highest sensitivity (96.3%) and accuracy (87.8%). Enhancing internal septation showed the highest specificity (90.9%). The κ values with confidence ratings for differentiation between MCs and FAs were 0.63–0.67, which showed substantial agreement among the three radiologists. ConclusionsThe combination of irregular margin and delayed heterogeneous enhancement and enhancing internal septation were significant findings for differentiation between P-MC or M-MC similar to P-MC and FA.

MRI features of breast lymphoma: preliminary experience in seven cases.

We aimed to evaluate the imaging features of breast lymphoma using magnetic resonance imaging (MRI). This retrospective study consisted of seven patients with pathologically confirmed breast lymphoma. The breast lymphomas were primary in six patients and secondary in one patient. All patients underwent preoperative dynamic contrast-enhanced MRI and one underwent additional diffusion-weighted imaging (DWI) with a b value of 600 s/mm2. Morphologic characteristics, enhancement features, and apparent diffusion coefficient (ADC) values were reviewed. On MRI, three patients presented with a single mass, one with two masses, two with multiple masses, and one with a single mass and a contralateral focal enhancement. The MRI features of the eight biopsied masses in seven patients were analyzed. On MRI, the margins were irregular in six masses (75%) and spiculated in two (25%). Seven masses (87.5%) displayed homogeneous internal enhancement, while one (12.5%) showed rim enhancement. Seven masses (87.5%) showed a washout pattern and one (12.5%) showed a plateau pattern. The penetrating vessel sign was found in two masses (25%). One patient with two masses underwent DWI. Both masses showed hyperintense signal on DWI with ADC values of 0.867×10-3 mm2/s and 0.732×10-3 mm2/s, respectively. Breast lymphoma commonly presents as a homogeneously enhancing mass with irregular margins and displays a washout curve pattern on dynamic MRI. A low ADC value may also indicate a possible diagnosis of breast lymphoma.

MRI features of mucinous carcinoma of the breast: correlation with histopathology

Objective To characterize the features of breast mucinous carcinoma on T2WI, dynamic contrast-enhanced MR imaging (DCE-MRI) and diffusion weighted imaging (DWI) and correlate the MR features with histopathology. Methods MR imaging in 8 women (aged 33--65 years old) with mncinous carcinoma of the breast verified histopathologically was performed on 1.5 T scanner with T1WI, FS T2 WI, 3D DCE-MRI using volume imaging for breast assessment(VIBRANT) sequence, DWI with b value of 500 and 1000 s/mm2 by single-shot EPI sequence. According to the lexicon of BI-RADS-MRI designed by ACR, the MR findings were retrospectively studied, including morphology, signal intensity on T1WI and FS T2WI, mass enhancement, the patterns of dynamic enhancement curve, and the mean ADC on DWI. The pathologic diagnosis was made according to the standard criteria by the World Health Organization Classification of Tumors. Results Five patients were pure mucinous carcinoma and 3 patients were the mixed. The amount of mucus ranged from 60% to 90%. All 8 tumors presented as a mass on MRI with low signal intensity on T1WI, high or strongly high signal intensity on FS T2WI and high signal on DWI. The tumor size ranged from 1.3 to 3. 2 cm in diameter. Five tumors showed rim enhancement in early phase and the central part was gradually enhanced in delayed phase. One tumor presented slightly heterogeneous enhancement. Two tumors showed progressively heterogeneous enhancement. The mean ADC values of tumor were (2.41±0.28) ×10-3 mm2/s with b value of 500 s/mm2 and (2.06 ±0. 14) × 10-3 mm2/s with b value of 1000 s/mm2, and higher than that of the normal breast tissue [ ( 1.71 ±0. 32) × 10-3 and ( 1.43 ± 0. 24) × 10-3 mm2/s]. Conclusions The MR features of breast mucinous carcinoma on T1WI, DCE-MRI, and DWI are different from that of invasive ductal carcinomas and may reflect its distinct histological type. The combination of these MR sequences may lead to a pre-operative diagnosis of this tumor. Key words: Breast neoplasms; Diffusion magnetic resonance imaging

Liver and pancreas

Various inflammatory processes and atypically appearing benign masses can have an imaging appearance very similar to or in some cases indistinguishable from cancer. In the liver such processes include inflammatory pseudotumor, sclerosed hemangioma and focal hepatic steatosis. In the pancreas heterotopic splenule, focal autoimmune pancreatitis and solid serous cystadenoma may be difficult to distinguish from pancreatic adenocarcinoma or neuroendocrine tumor. Inflammatory Pseudotumor is a localized benign hepatic mass that consists of fibrous stroma and chronic inflammatory infiltrates including plasma cells, histiocytes and lymphocytes. Three subtypes are recognized: xanthogranuloma type (histiocyte predominance), plasma cell granuloma type and hyalinized sclerosing type. The pathogenesis is unclear, but it often is associated with chronic recurrent biliary infections. The most common CT/MR appearance of inflammatory pseudotumor is that of a peripherally enhancing mass with a central area of poor enhancement. Histopathologically, the peripheral enhancing portion of the mass corresponds to fibroblastic proliferation, whereas the central poorly enhancing area corresponds to chronic inflammatory infiltrates. Other appearances include a solid mass with progressive homogeneous enhancement (hyalinized sclerosing type) and a necrotic appearing mass with internal septations. Differential diagnosis includes abscess, metastasis, cholangiocarcinoma and hepatocellular carcinoma. Hemangioma, the most common noncystic hepatic mass, has well recognized imaging characteristics; however, a hemangioma that has undergone degeneration and fibrous replacement (sclerosed hemangioma) may have atypical imaging features that can mimic a malignant hepatic neoplasm, in particular cholangiocarcinoma or metastasis. The imaging appearance varies depending on the degree of sclerosis. The mass often has an irregular contour and may cause capsular retraction if located peripherally. It may show rim enhancement or nodular peripheral enhancement; however, in contradistinction to most hemangiomas the enhancement is static and does show the usual centripetal progression. On MR imaging the mass may lack the expected degree of T2 hyperintensity. If serial imaging is available, a sclerosed hemangioma may decrease in size over time, with loss of previous regions of enhancement. Intrapancreatic splenuleappears as a round enhancing mass within the tail of the pancreas. Because of its vascularity it can be mistaken for a pancreatic neuroendocrine tumor. One of the keys to diagnosis is recognition that the mass has enhancement, attenuation and/or signal intensity characteristics that parallel the spleen on all image acquisitions. The diagnosis can be confirmed with a technetium 99m heat-damaged red blood cell scan, which demonstrates radiotracer uptake within the mass. Mass-forming chronic pancreatitis, particularly autoimmune pancreatitis, frequently is misdiagnosed as pancreatic adenocarcinoma or a neuroendocrine tumor. Most commonly mass-forming chronic pancreatitis is isoattenuating/isointense during both the pancreatic and hepatic parenchymal phases of contrast enhancement. In contradistinction, pancreatic adenocarcinoma typically is hypoattenuating/hypointense during both enhancement phases; however, approximately 10% of pancreatic adenocarcinomas are isoattenuating/isointense during both phases. On MR cholangiopancreatography (MRCP) the pancreatic duct within the mass-forming pancreatitis may be visible but narrowed (duct-penetrating sign), whereas the duct within pancreatic carcinoma often is occluded. One study has shown the duct-penetrating sign to be 94% accurate in distinguishing the two entities. Elevation of serum IgG4 is the best serological marker for autoimmune pancreatitis (sensitivity 73-75%; specificity 93-95%); however, approximately 10% of patients with pancreatic cancer may have elevated IgG4. Pancreatic serous cystadenoma is a benign mass that consists of numerous tiny cysts separated by glandular tissue and fibrous stroma. On CT it appears as a well-circumscribed hypoattenuating mass with varying degrees of contrast enhancement, depending on the size of the cysts and the proportion of cystic to glandular tissue. In most cases it is not difficult to distinguish this multicystic lesion from a solid pancreatic neoplasm; however a small proportion of serous cystadenomas consist largely of glandular tissue and fibrous septa with only a small proportion of tiny cysts. Such lesions appear hypervascular and may mimic a pancreatic neuroendocrine tumor. Clues to the diagnosis include precontrast attenuation value within the range of fluid and the presence of small cystic areas with the enhancing mass. In addition, this diagnosis should be considered if the mass is found incidentally in an elderly individual or a patient with von Hippel Lindau disease.

Ultrasound with microbubbles

Conventional ultrasound has well known short comings in the detection and characterisation of focal liver lesions. A false negative rate of up to 30% has been quoted in the detection of liver metastases and its accuracy in the characterisation of focal liver lesions is poor compared to computed tomography (CT) and magnetic resonance (MR). Ultrasound microbubble contrast agents have redressed these limitations. Ultrasound microbubbles have been available for over 20 years and are licensed for clinical use in most parts of the world. The characterization of focal liver lesions is the most important application of contrast-enhanced US (CEUS), with an accuracy rivalling that of CT and MR [1-8]. Microbubbles consist of a low solubility complex gas such as a perfluoro gas surrounded by a phospholipid shell. They are similar in size to red blood cells, in comparison to the molecular sizes of CT and MR contrast agents. They are pure intravascular agents. Following an intravenous injection they last in the circulation for about 5 minutes. By good fortune, microbubbles resonate in an ultrasound field at the frequencies used in everyday diagnostic sonography. During resonance they emit ‘fingerprint like’ harmonic signals (overtones) which can be selectively detected by the microbubble-specific software available on commercial ultrasound systems. Microbubbles are imaged using low acoustic power modes to reduce their destruction and thus allow real-time imaging. They are better tolerated than MR and CT agents with fewer and less severe adverse effects and are not nephrotoxic. The most widely used agent in Europe is Sonovue (Bracco). The liver demonstrates three phases of enhancement after an i.v. bolus injection: the arterial, portal and late phases. The late phase occurs as the vascular phases subside, when the microbubbles are sequestered in the sinusoids of the liver. Enhancement is visualized in real time alongside a B-mode greyscale image. The enhancement characteristics of liver lesions at CEUS are similar to those seen on CT and MR imaging. Since CEUS operates in real time, fast changes during the arterial phase are better captured than on CT or MR. This presentation discusses the enhancement characteristics of malignant and benign liver lesions. As a general rule, however, lesions which do not washout in the late phase (i.e. remain hyperenhancing or isoenhancing to liver parenchyma) tend to be benign (with the exception of simple cysts, haematomas, ablation cavities and abscesses, which do not enhancement in any phase), whereas lesions which do not retain contrast in the late phase (i.e. demonstrate washout) are usually malignant. Hepatic metastases have variable appearances on B-mode ultrasound. On CEUS, hypervascular metastases typically demonstrate avid enhancement throughout the lesion in the arterial phase whilst hypovascular metastases show rim enhancement in the arterial phase with both types showing washout in the late phases appearing as defects. CEUS significantly increases the conspicuity of metastases compared to B mode, allowing the detection of isoechoic and lesions down to 3mm. CEUS and intervention: The use of CEUS may allow better visualisation of a lesion than on B-mode ultrasound and allow a targeted ultrasound-guided biopsy. CEUS may also be used during interstitial ablation of a focal malignant liver lesion. The operator is able to perform repeated injections of microbubbles in order to establish whether viable tumour remains, and whether immediate further on-table ablative therapy is required. Benign liver lesions have characteristic enhancement patterns on CEUS. Haemangiomas demonstrate gradual peripheral nodular enhancement with progressive centripetal filling whereas focal nodular hyperplasia typically demonstrate avid arterial centrifugal enhancement in a Correspondence: chris.harvey@imperial.nhs.uk Imperial College Healthcare NHS Trust, Hammersmith Hospital, London W12 0HS, UK Harvey Cancer Imaging 2015, 15(Suppl 1):O19 http://www.cancerimagingjournal.com/content/15/S1/O19

MRI findings of inflammatory breast diseases with pathologic correlation in non-lactating woman

Objective To evaluate the MRI findings of inflammatory breast diseases with pathologic correlation in non-lactating woman.Methods Seventy-eight patients with non-lactating inflammatory breast diseases confirmed by surgicopathology were respectively reviewed.All these patients had a preoperative dynamic contrast-enhanced MRI examination,and 27 had undergone the DWI.MRI findings were reviewed for dynamic enhancement characteristics and the DWI findings.The internal enhancement patterns were classified as rim enhancement,heterogeneous(Ⅰ and Ⅱ),homogenous enhancement,and clumped enhancement.The four main pathological findings were reviewed as follows:abscess,dilated duct,inflammatory cyst,and other inflammatory changes.The MRI findings of the lesion and the corresponding pathological features were analyzed.Results Among the 78 patients,internal enhancement patterns were rim enhancement(n=55),heterogeneous enhancement Ⅰ (n=10),heterogeneous enhancement Ⅱ(n=9),homogenous enhancement(n=2),and clumped enhancement(n=2).Of the 27 patients who underwent DWI,17 patients showed rim enhancement and a central hyperintensity on DWI,the pathological findings were more frequently inflammatory cyst(n=9) and abscess(n=8).One patient showed rim enhancement and a peripheral hyperintensity on DWI,the pathological finding was an inflammatory cyst.Of the 3 patients showing heterogeneous enhancement Ⅰ and heterogenous hyperintensity on DWI,the pathological findings were other inflammatory changes.Of the 6 patients showing heterogeneous enhancement Ⅱ and oval or linear hyperintensity on DWI,the pathological findings were abscess(n=5) and dilated duct(n=3).Conclusions Inflammatory breast diseases in non-lactating women show relative characteristic features on MRI.MRI findings of these kinds of diseases are associated with its pathological background. Key words: Mastitis; Magnetic resonance imaging; Pathology

Differentiation of Spinal Schwannomas and Myxopapillary Ependymomas

Retrospective clinical study. The objective of this study is to evaluate magnetic resonance imaging and pathologic features of spinal schwannomas (SCHs) and myxopapillary ependymomas (MPEs) with focus on differentiating 2 disease entities. Few studies have reported on the differentiation of SCHs and MPEs. Fifty-three patients were retrospectively reviewed with histologically confirmed spinal SCHs (41 patients) or MPEs (12 patients) of the cauda equina and/or conus medullaris. We evaluated neurological deterioration after surgery in association with the intraoperative findings of the tumor, as well as with the preoperative magnetic resonance images and postoperative histologic findings. Patients in the SCH group had a greater mean age at surgery and a greater mean disease duration. In the SCH group, all 24 tumors that were homogeneously hyperintense on the T2-weighted (T2W) images showed rim enhancement on the postcontrast T1-weighted (T1W) images. Moreover, all 14 of the SCHs with homogeneous enhancement on the postcontrast T1W images were isointense on the T2W images. However, in the MPE group, all 8 of the tumors that were homogeneously hyperintense on T2W images showed homogeneous enhancement on their postcontrast T1W images. It is very important to differentiate SCHs and MPEs before surgery, because there are reported cases of dissemination of MPEs through cerebrospinal fluid throughout the neuraxis; the tumor must be removed en block to prevent this. Although MPEs and SCHs may have similar imaging characteristics, detailed examination of the magnetic resonance T2W image and postcontrast T1W image facilitates their differentiation.