Marked Contrast Enhancement Research Articles

Seeking for Innovation with Magnetic Resonance Imaging Paramagnetic Contrast Agents: Relaxation Enhancement via Weak and Dynamic Electrostatic Interactions with Positively Charged Groups on Endogenous Macromolecules.

Gd-L1 is a macrocyclic Gd-HPDO3A derivative functionalized with a short spacer to a trisulfonated pyrene. When compared to Gd-HPDO3A, the increased relaxivity appears to be determined by both the higher molecular weight and the occurrence of an intramolecularly catalyzed prototropic exchange of the coordinated OH moiety. In water, Gd-L1 displayed a relaxivity of 7.1 mM-1 s-1 (at 298 K and 0.5 T), slightly increasing with the concentration likely due to the onset of intermolecular aggregation. A remarkably high and concentration-dependent relaxivity was measured in human serum (up to 26.5 mM-1 s-1 at the lowest tested concentration of 0.005 mM). The acquisition of 1H-nuclear magnetic relaxation dispersion (NMRD) and 17O-R2 vs T profiles allowed to get an in-depth characterization of the system. In vitro experiments in the presence of human serum albumin, γ-globulins, and polylysine, as well as using media mimicking the extracellular matrix, provided strong support to the view that the trisulfonated pyrene fosters binding interactions with the exposed positive groups on the surface of proteins, responsible for a remarkable in vivo hyperintensity in T1w MR images. The in vivo MR images of the liver, kidneys, and spleen showed a marked contrast enhancement in the first 10 min after the i.v. injection of Gd-L1, which was 2-6-fold higher than that for Gd-HPDO3A, while maintaining a very similar excretion behavior. These findings may pave the way to an improved design of MRI GBCAs, for the first time, based on the setup of weak and dynamic interactions with abundant positive groups on serum and ECM proteins.

MRI characteristics of H3 G34-mutant diffuse hemispheric gliomas and possible differentiation from IDH-wild-type glioblastomas in adolescents and young adults.

H3 G34-mutant diffuse hemispheric gliomas (G34m-DHGs) are rare and constitute a new infiltrating brain tumor entity whose characteristics require elucidation, and their difference from isocitrate dehydrogenase-wild-type glioblastomas (IDH-WT-GBMs) needs to be clarified. In this study, the authors report the demographic, clinical, and neuroradiological features of G34m-DHG and investigate the capability of quantitative MRI features in differentiating them. Twenty-three patients with G34m-DHG and 30 patients with IDH-WT-GBM were included in this retrospective study. The authors reviewed the clinical, radiological, and molecular data of G34m-DHGs and compared their neuroimaging features with those of IDH-WT-GBMs in adolescents and young adults. Visually Accessible Rembrandt Images (VASARI) features were extracted, and the Kruskal-Wallis test was performed. A logistic regression model was constructed to evaluate the diagnostic performance for differentiating between G34m-DHG and IDH-WT-GBM. Subsequently, FeAture Explorer (FAE) was used to generate the machine learning pipeline and select important radiomics features that had been extracted with PyRadiomics. Estimates of the performance were supplied by metrics such as sensitivity, specificity, accuracy, and area under the curve (AUC). The mean age of the 23 patients with G34m-DHG was 23.7 years (range 11-45 years), younger than the mean age of patients with IDH-WT-GBM (30.96 years, range 5-43 years). All tumors were hemispheric. Most cases were immunonegative for ATRX (95%) and Olig2 (100%), were immunopositive for p53 (95%), and exhibited MGMT promoter methylation (81%). The radiological presentations of G34m-DHG were different from those of IDH-WT-GBM. The majority of the G34m-DHGs were in the frontal, parietal, and temporal lobes and demonstrated no or only faint contrast enhancement (74%), while IDH-WT-GBMs were mostly seen in the frontal lobe and showed marked contrast enhancement in 83% of cases. The FAE-generated model, based on radiomics features (AUC 0.925) of conventional MR images, had better discriminatory performance between G34m-DHG and IDH-WT-GBM than VASARI feature analysis (AUC 0.843). G34m-DHGs most frequently occur in the frontal, parietal, and temporal lobes in adolescent and young adults and are associated with radiological characteristics distinct from those of IDH-WT-GBMs. Successful identification can be achieved by using either VASARI features or radiomics signatures, which may contribute to prognostic evaluation and assist in clinical settings.

Computed tomographic, magnetic resonance imaging, and ultrasonographic characteristics of retrobulbar meningiomas in 15 dogs.

Meningioma is the most common tumor of the cranium in dogs and an important differential diagnosis for a potentially treatable disease that can be found in the periorbital tissues. The objective of this retrospective, case series study was to describe the CT, MRI, and US characteristics of confirmed retrobulbar meningiomas in a group of dogs. Medical records from multiple institutions were searched for canine patients with CT, MRI, and/or US imaging of a cytologically or histologically confirmed retrobulbar meningioma. Fifteen dogs met the inclusion criteria. Retrobulbar meningiomas typically appeared as a relatively well-defined conical to ovoid mass within the retrobulbar space, most often along the optic nerve and expanding the extraocular muscle cone. On CT, masses were predominantly soft tissue attenuating and variably heterogeneously contrast enhancing. While MRI features were variable, moderate to marked contrast enhancement was seen in all cases. Many of the tumors had evidence of partial mineralization, best appreciated on CT in nine patients, but also suspected based on susceptibility artifacts in three MRI cases, one of which was confirmed on CT. Regional osteolysis was a rare finding, noted in three cases, but was often accompanied by cranial cavity extension (2/3). Cranial cavity extension was also seen in the absence of regional osteolysis, identified in a total of six patients. On US, masses were echogenic and compressed the globe. The findings were consistent with previous gross and histologic descriptions and supported prioritizing retrobulbar meningioma as a differential diagnosis for dogs with the described imaging characteristics.

Variations in the morphology of lagomorph confluence sinuum on contrast enhanced CT.

Knowledge of lagomorph confluence sinuum anatomy on contrast-enhanced CT may prevent the misdiagnoses of intracranial, extra-axial masses. The purpose of this retrospective, observational, descriptive study was to describe the characteristics of the confluence sinuum in rabbits on contrast-enhanced CT. Images of 24 rabbits who had pre- and postcontrast CT sequences of the skull were reviewed by an American College of Veterinary Radiology-certified veterinary radiologist and third-year radiology resident. Degree of contrast enhancement within the region of the confluence sinuum was graded based on consensus as no (0), mild (1), moderate (2), or marked (3) contrast enhancement. Hounsfield units (HU) of the confluence sinuum was measured in three different regions of interest, averaged for each patient, and divided into each group for comparison using one-way ANOVA analysis. Contrast enhancement was mild in 45.8% (11/24) rabbits, moderate in 33.3% (8/24), marked in 20.8% (5/24), and none in 0.0% (0/24). There were significant differences (P<0.05) between the average HU of the mild and marked group (P-value=0.0001) and moderate and marked groups (P-value=0.0010). Two rabbits with marked contrast enhancement were initially misdiagnosed with an intracranial, extra-axial mass along the parietal lobe based on contrast-enhanced CT. On necropsy, no gross or histopathological abnormalities were identified in the brain for these rabbits. In summary, contrast enhancement was identified in all rabbits (24/24) on contrast-enhanced CT imaging . This normal structure can be variable in size should not be mistaken for a pathological lesion in the absence of mass effect, secondary calvarial lysis, or hyperostosis.

Pulmonary Cystic Echinococcosis in Contrast-enhanced Ultrasound - A Case Report.

Pulmonary cystic echinococcosis is a parasitic infection transmitted by dogs and occurring in livestock-raising areas. It is included among the neglected tropical diseases, according to the World Health Organization. Imaging plays a pivotal role in the diagnosis of this disease. While cross-sectional imaging modalities such as computed tomography and magnetic resonance imaging are preferred, lung ultrasound may be another feasible technique. We report a case of pulmonary cystic echinococcosis in a 26-year-old woman who was examined by contrast-enhanced ultrasound, which showed marked annular enhancement around the hydatid cyst, mimicking a superinfected cyst. Contrast-enhanced ultrasound examination in pulmonary cystic echinococcosis should be studied in a larger population to determine the value of additional contrast administration. In the present case report, no superinfected echinococcal cyst was seen despite marked annular contrast enhancement.

Primary synovial sarcoma on MRI - a case series and review of the literature.

Simple MRI features are mandatory to facilitate the diagnostics of synovial sarcomas, especially for radiolo-gists outside multidisciplinary sarcoma centres. In this case-series and review, we investigate the main appearance of synovial sarcoma on MRI. Fifteen histologically proven primary synovial sarcomas who underwent MRI at 2 different sarcoma centres were included in this case series. Patients and their primary synovial sarcomas were examined for age, localization, mean tumour size (in mm), histological grade (G - according to the Fédération Nationale des Centres de Lutte Contre Le Cancer [FNCLCC]), configuration, T2 signal intensity, presence/absence of "triple sign", heterogeneity/homogeneity, borders (well-defined or infiltrative), and intensity of contrast enhancement on MRI. Additionally, a comprehensive literature review to identify observational studies, reviews, and case-reports assessing MRI features of primary synovial sarcoma was performed. The mean age of the patients was 47.6 years (SD: 17.2). The mean size of primary synovial sarcoma was 59.3 mm (SD: 42). Primary synovial sarcomas were significantly most often multilobulated (n = 12, p < 0.01), heterogeneous (n = 10), and infiltrative (n = 9). Additionally, 3 other primary synovial sarcomas showed the following configurations: ovoid/nodular (n = 2) and fascicular (n = 1). Ovoid/nodular synovial sarcomas were solely depicted as homogeneous with well-defined borders. All tumours showed T2 hyperintense signal and presented with marked contrast enhancement. Primary synovial sarcomas are mainly multilobulated, heterogeneous, and infiltrative tumours. In minor cases, ovoid/nodular or fascicular configurations occur. Knowing the main appearance of synovial sarcoma can help facilitate the diagnostics of primary synovial sarcomas.

Long‐term outcome of infectious sacroiliitis due to Pasteurella multocida in a dog

AbstractA 6‐month‐old, male German shepherd dog was presented with a 2‐week history of left pelvic limb lameness. Physical examination revealed severe left pelvic limb lameness, lumbosacral and left pelvic limb pain. Magnetic resonance imaging showed heterogeneous T2‐weighted hyperintensity, T1‐weighted hypointense with marked contrast enhancement in the left sacroiliac joint, consistent with unilateral sacroiliitis. Computed tomography was used to perform image‐guided arthrocentesis and also revealed an irregular left sacroiliac joint. Infectious sacroiliitis, caused by Pasteurella multocida, was confirmed by culture of the synovial fluid of the sacroiliac joint. Infectious sacroiliitis should be considered as a differential diagnosis for young dogs presented with pelvic limb lameness and pain.

Advanced MRI features of intraventricular inflammatory myofibroblastic tumor: a case report

BackgroundInflammatory myofibroblastic tumor (IMT) is a rare central nervous system (CNS) tumor. We first report a rare case of IMT in the lateral ventricle and describe the magnetic resonance imaging (MRI) findings of the tumor with an emphasis on the advanced MRI features.Case presentationA 49-year-old female patient with headaches and blurred vision for 2 months. Brain MRI revealed a well-circumscribed, lobulated mass occupying the left lateral ventricle trigone, with marked perilesional brain edema. The tumor showed heterogeneous significant hyperintensity on T2-weighted imaging (T2WI) and hypointensity on T1-weighted imaging (T1WI). After the administration of gadolinium, the mass exhibited marked contrast enhancement and the halo sign was observed. On advanced MRI, the lesion showed decreased perfusion on perfusion MRI and reduced diffusion on diffusion-weighted imaging (DWI). On susceptibility-weighted imaging (SWI), there was a punctate low signal intensity in the tumor. The patient underwent surgical resection of the mass and a pathological examination confirmed the lesion to be an inflammatory myofibroblastic tumor with negative expression of anaplastic lymphoma kinase (ALK). This patient had remained healthy without evidence of recurrence during a 20-month follow-up.ConclusionsOn MRI, marked perilesional brain edema, significant hyperintensity on T2WI, hypoperfusion on perfusion MRI but with an obvious enhancement, no diffusion restriction on DWI, and halo sign may be the characteristic findings of intraventricular IMT. The advanced MRI characteristics could provide abundant information to reflect the histological features and physiological metabolic characteristics of the tumor.

109 Juvenile granulosa cell tumor of the ovary as a cause of isosexual precocious puberty in a 3-year-old girl

Objective: The etiology of most cases of precocious puberty in girls is idiopathic and can develop due to central or peripheral causes [ [1] Cisternino M. Arrigo T. Pasquino A.M. et al. Etiology and age incidence of precocious puberty in girls: a multicentric study. J Pediatr Endocrinol Metab. 2000; 13: 695 Crossref PubMed Google Scholar ]. Juvenile granulosa cell tumor (JGCT) of the ovary can be seen as a rare cause of peripheral precocious puberty. [ 2 Young R.H. Dickersin G.R. Scully R.E. Juvenile granulosa cell tumor of the ovary. A clinicopathological analysis of 125 cases. Am J Surg Pathol. 1984; 8: 575 Crossref PubMed Scopus (370) Google Scholar , 3 Wu H. Pangas S.A. Eldin K.W. et al. Juvenile granulosa cell tumor of the ovary: a clinicopathologic study. J Pediatr Adolesc Gynecol. 2017; 30: 138-143 Abstract Full Text Full Text PDF PubMed Scopus (35) Google Scholar ]. We describe a case of JGCT presented with isosexual precocious puberty in a three-year-old- girl. Case: A three-year-old- girl presented with a three-week history of vaginal bleeding. She had also started having some breast development during the past few months. Her past medical and surgical history were unremarkable. On physical examination, she had Tanner stage 2 breast and stage 1 pubic hair development. Perineal inspection revealed normal anatomy of the external genitalia and no mass or foreign body. There was also no sign of vulvovaginitis or trauma. Vaginal mucosa looked estrogenized. Transabdominal ultrasound showed a normal prepubertal uterus with increased endometrial thickness and an approximately 6-cm solid adnexal mass on the left. Laboratory investigations revealed elevated estradiol level (117 pg/mL) despite of prepubertal gonadotropin levels. Serum tumor markers included alpha-fetoprotein, beta human chorionic gonadotrophin and lactate dehydrogenase were normal, but inhibin B level was significantly elevated (1101 pg/ml). Magnetic resonance imaging (MRI) revealed a solid mass of approximately 6 cm in size in the left ovary with marked contrast enhancement and suspicious para-aortic lymph node involvement which was approximately 2 cm in size (Figure 1). Left salpingo-oophorectomy and excision of palpable paraaortic lymph nodes were performed through a lower midline incision (Figure 2). Postoperative period was uneventful. Histopathologic examination revealed FIGO stage 1A JGCT of the left ovary and reactive lymph nodes without tumor metastasis. Her estradiol level was < 5 pg/ml and inhibin level < 3.6 pg/ml at 4 weeks postoperatively. Adjuvant chemotherapy was not indicated due to early stage of the disease. Conclusion: This report highlights the importance of screening for peripheral causes of precocious puberty such as hormone-secreting tumors of the gonads or adrenal glands, especially in the presence of elevated estrogen level despite of prepubertal gonadotropin levels.

Prostate Cancer Imaging: What We Already Know and What Is on the Horizon.

Prostate Cancer Imaging: What We Already Know and What Is on the Horizon.

MRI enhancement patterns in 28 cases of clival chordomas

Clival chordomas are classically thought of as locally aggressive tumors of the skull base and differentiate themselves from their benign counterparts by demonstrating moderate to marked contrast enhancement, reported as 95–100% in prior studies. The purpose of this review was to evaluate the imaging characteristics of lesions from a single institution classified as clival chordomas with an emphasis of highlighting lesions that do not follow the prevalent current description for chordoma. We searched our institutional databases for all patients with pathologically proven clival chordomas from 1997 to 2017 who had pre-operative imaging available. The images were evaluated for degree of contrast enhancement, MRI signal characteristics, osseous involvement, location, aggressiveness of appearance, and presence of calcifications. 28 cases were identified that had preoperative imaging available for review. Over half of the patients demonstrated either no/minimal (11/28, 39%) or mild enhancement (7/28, 25%). The remaining cases demonstrated moderate (4/28, 14%) and marked enhancement (6/28, 21%). The 4 lesions measuring less than 20 mm all had mild to minimal/no enhancement and lacked aggressive features on CT. Our experience finds that over half (64%) of clival chordomas will demonstrate mild or no enhancement at all. These findings suggest that the lack of MRI contrast enhancement should not be synonymous with a benign clival mass.

Melanocytic lesions of the central nervous system: a case series.

Melanocytic lesions of the central nervous system (CNS) are an infrequent, broad and diverse group of entities, both benign and malignant, found in all age groups, with imaging findings ranging from well-circumscribed focal lesions to diffuse leptomeningeal involvement. On MRI, they are usually distinguished by a high signal on T1WI sequences, given the paramagnetic effect of melanin, thus making it difficult to differentiate among them. To describe the imaging and epidemiological characteristics of a retrospective series of CNS melanocytic lesions. MR images of 23 patients with CNS melanocytic lesions diagnosed between January 2012 and June 2018 were analyzed. Most patients were female (14/23; 61%), with a median age of 47 years (range: 3 weeks to 72 years). The primary melanocytic lesions accounted for 8/19 cases (42.1%), which included neurocutaneous melanosis, meningeal melanocytomas and primary malignant melanomas. Secondary melanocytic lesions (metastatic) accounted for 10/19 cases (52.6%). There was one case of a tumor with secondary melanization, from a melanocytic neuroectodermal tumor of infancy. There were also four cases of primary ocular melanomas. The most frequent findings were the cerebral location, high T1WI signal and marked contrast-enhancement. The present review describes the wide variety of melanocytic lesions that could affect the CNS, emphasizing the MRI characteristics. Knowledge of the imaging, clinical and epidemiological characteristics of CNS melanocytic lesions is essential for their correct interpretation, given the significant overlap between lesion features and the variable prognosis.

Multifocal cryptococcosis diagnosis by peripheral lymph node aspirates in a cat

AbstractA 4‐year‐old, female, neutered, domestic shorthair cat presented with a 5‐day history of progressive inappetence, obtundation, vestibular ataxia and tetraparesis. Neurological examination findings on presentation were consistent with a multifocal localisation (central vestibular with cerebellar involvement). Magnetic resonance imaging of the head showed diffuse brain parenchymal swelling, foramen magnum herniation, diffuse meningeal contrast enhancement and lymphadenopathy (enlargement and marked contrast enhancement of the parotid, mandibular and medial retropharyngeal lymph nodes). Fine‐needle aspirates of the retropharyngeal and prescapular lymph nodes showed macrophagic and eosinophilic inflammation with multiple yeast organisms on cytology, consistent with Cryptococcus spp. The cat suffered a cardiopulmonary arrest following diagnosis, suspected secondary to severe brainstem compression. The findings emphasise that systemic cryptococcosis can cause severe clinical signs, including presumptive central nervous system dysfunction, as in this cat. Furthermore, this case adds to the limited descriptions of neurological presentations and imaging findings associated with cryptococcosis in companion animals in the United Kingdom.

Predicting Subtype of Growth Hormone Pituitary Adenoma based on Magnetic Resonance Imaging Characteristics.

This study aimed to investigate the value of magnetic resonance (MR) characteristics in differentiating the subtypes of growth hormone pituitary adenomas. The clinical and MR imaging data of 70 patients with growth hormone pituitary adenoma confirmed by surgery and pathology were retrospectively analyzed. The tumors were divided into dense granular (DG; 36 cases) and sparse granular subtypes (SG; 34 cases). The tumors' MR features were analyzed, including the mean and maximum diameters, T2 signal intensity, T2 relative signal intensity (rSI), homogeneity, enhancement degree, and invasiveness (Knosp grade). Mann-Whitney U test and χ2 test were used to analyze MR characteristics between the 2 groups. The independent predictors and predictive probabilities of tumor subtypes were obtained via a logistic regression model, and the efficacy was compared by receiver operating characteristic curve. The mean and maximum diameters of growth hormone adenoma in DG and SG were 1.77 versus 2.45 and 1.95 versus 3.00 cm (median, P < 0.05), respectively. There was a significant difference between the 2 groups in T2 signal intensity and rSI (P values were 0.02 and 0.001, respectively). Most DG adenomas (86.1%) appeared as hypointense on T2 images, and 38.2% of SG adenomas were hyperintense. There was no significant difference in tumor homogeneity (P = 0.622). A significant difference was found in the Knosp grade between the 2 subtypes (P = 0.004). In addition, the enhancement degree of SG adenomas was significantly higher than that of DG adenomas (P = 0.001). Logistic regression analysis showed that high T2 rSI value and marked contrast enhancement were independent predictors of the 2 subtypes, and the odds ratios were 4.811 and 4.649, respectively. The multivariate logistic model obtained relatively high predicting efficacy, and the area under the curve, sensitivity, and specificity were 0.765, 0.882, and 0.500, respectively. There are significant differences in tumor size, T2 signal intensity, T2 rSI, enhancement degree, and invasiveness between DG and SG adenomas. The logistic model based on the marked contrast enhancement and high T2 rSI value has an important value in predicting the subtype of growth hormone adenoma.

Misdiagnosis and Delay of Diagnosis in Hemorrhagic Meningioma: A Case Series and Review of the Literature

To evaluate the clinicoradiologic characteristics of hemorrhagic meningiomas (HMs) that are missed or misdiagnosed on radiologic imaging studies. Clinical and radiologic data from 6 patients with HM who were initially misdiagnosed were collected and recorded respectively. In addition, we performed a literature review for misdiagnosed HM and summarized the results. Five of the 6 patients with misdiagnosed HM were female, and 1 was male. Both computed tomography (CT) and magnetic resonance imaging were performed in 4 patients, and CT alone was performed in 2. On CT, the HM was heterogeneously hyperdense in 5 patients and isodense in 1 patient. In all 4 patients who underwent magnetic resonance imaging, the HM was mixed iso- and hypointense on T1-weighted imaging and heterogeneously hyperintense on T2-weighted imaging. Marked heterogeneous contrast enhancement was observed in 2 patients, strong rim enhancement in 1, and peripheral enhancement in 1. The dural tail sign was seen in only 1 patient. The initial radiologic misdiagnoses were subdural hematoma (n= 1), malignant glioma (n= 1), ruptured arterial aneurysm (n= 1), metastasis (n= 2), and uncertain (n= 1). In the literature review, 22 cases of HM diagnostic error were collected. The main misdiagnoses were subdural hematoma (27.3%), traumatic hematoma (13.6%), vascular anomaly (13.6%), malignant glioma (4.5%), and metastasis (4.5%). Our study showed that in patients with HM with inadequate imaging evaluation, a small tumor associated with massive hematoma and atypical imaging features was more likely to be misdiagnosed.

White matter imaging of ethanol-fixed rat brain by phase-contrast X-ray computed tomography.

Phase-contrast X-ray computed tomography imaging (PCI) based on crystal X-ray interferometry can detect minute density differences within biological soft tissues without contrast agents. Ethanol fixation yields increased tissue-background density differences due to the dehydrating and delipidifying effects of ethanol. To obtain high image contrast of cerebral white matter structures in PCI, tissue fixation using ethanol and routinely used formalin have been examined. Ethanol-fixed (EF) (n = 4) and formalin-fixed (FF) (n = 4) rat brains were imaged by crystal X-ray interferometry-based PCI. Tissue staining/microscopy was also performed for histological comparison and myelin density evaluation. Three-dimensional white matter tract images were reconstructed. Superior image contrast was obtained in the images of EF brains (EF images) compared to those of formalin-fixed brains (FF images), particularly for white matter structures. Significant density differences between the white matter structures and hippocampus (P < 0.01)/thalamus (P < 0.001) were observed in the EF, but not FF, images. Ethanol fixation enhanced the image contrast of white matter tracts by approximately sixfold compared to formalin fixation, and close agreement (r2 = 0.97; P < 0.05) between the density values on the CT images and the myelin density values in histological images was observed for the EF brains. Three-dimensional reconstruction of the white matter tracts was possible from the EF images, but not FF images. Ethanol fixation resulted in marked contrast enhancement of cerebral white matter structures in PCI. Thus, high-resolution PCI using ethanol for tissue fixation could be valuable for experimental neurological studies and postmortem neuropathology evaluation.

Appearance of recurrent dermatofibrosarcoma protuberans in postoperative MRI follow-up

Purpose: To analyze the appearance of recurrent dermatofibrosarcoma protuberans (DFSP) in postoperative MRI follow-up and to assess the occurrence of postoperative soft tissue changes detected in MRI.Methods: A total of 464 MRI follow-up scans of 32 patients with histologically proven diagnosis of DFSP were analyzed. MR imaging was performed using a 1.5T MRI system. Recurrent DFSP was examined for signal intensity, contrast behavior, appearance, and extent in MRI.Results: The mean age of the patients was 44,5±17,1 years. Recurrences of DFSP occurred 26±23.3 months after primary tumor resection in the mean (Min.: 9, Max.: 60). In 25% of the patients (n = 8), recurrences of DFSP were detected. Recurrent DFSP most often showed a nodular and homogeneous configuration with well-defined borders and marked contrast enhancement, and a hyperintense signal in PD-weighted and turbo inversion recovery magnitude sequences. All recurrences were well detected in the follow-up MRIs regardless of the performed plastic surgery procedure. Lateral and depth margins had no significant impact on the local recurrence rate. In all, 88% of the patients developed subcutaneous tissue edema (p < 0.01), followed by muscle edema (34%, p = 0.02), and postoperative seroma (22%).Conclusion: Recurrent DFSP mainly appear uniform and clearly delimitable on MRI as nodular, homogeneous, and well-defined lesions with marked contrast enhancement. Therefore, MRI is a valuable tool for postsurgical follow-up. Nearly all patients develop subcutaneous edema after the resection of DFSP.

Contrast-enhanced magnetic resonance imaging evidence for the role of astrocytic aquaporin-4 water channels in glymphatic influx and interstitial solute transport

The present study aimed to confirm the hypothesis that aquaporin-4 water channels (AQP4) control solute transition into the brain parenchyma using image analysis of gadolinium-based contrast agents (GBCAs) dissolved in cerebrospinal fluid (CSF) on dynamic contrast-enhanced magnetic resonance imaging (dyMRI) in live rats. Ten male Wistar ST rats were included in the study. Whole-brain dyMRI was performed for approximately 120 min after intrathecal infusion of gadolinium tetraazacyclododecane tetraacetic acid (Gd-DOTA). TGN-020, a specific AQP4 inhibitor, was used to inhibit the function of AQP4 in one group of rats (TGN-020 group, n = 4). The dyMRI after Gd-DOTA infusion in the rat, who were not treated with TGN-020 (control group, n = 6) revealed marked contrast-enhancement over time based on the distribution of the GBCA in the lateral regions of the brain surface, the ventral regions, the regions adjacent to the subarachnoid space, and the deep subcortical region. In contrast, smaller signal enhancement of the same regions in the TGN-020 group indicated poor distribution of the GBCA, suggesting a physiological consequence of the AQP4 inhibition by TGN-020. In this study, a close relationship between the function of AQP4 and the solute dynamics in the CSF was revealed from the distribution pattern of GBCA visualized in dyMRI in the living rat brain by administration of AQP4-selective inhibitor. This finding suggests that AQP4 functions to drive a glymphatic influx to transition molecules dissolved in the CSF from the subarachnoid space into the extracellular space of the brain parenchyma.

Appearance of recurrent adult fibrosarcoma of the soft tissue and loco-regional post-treatment changes on MRI follow-up

BackgroundAdult fibrosarcoma (AFS) is a very rare malignant soft tissue tumor, arising from malignant spindle-shaped fibroblasts. We aim to analyze the appearance of recurrent AFS with a focus on configuration and to assess the occurrence of loco-regional post-treatment changes on MRI follow-up.MethodsOne hundred sixty-eight MRI follow-up scans (1.5 T MRI) of 12 patients with histologically proven AFS were reviewed. The recurrent tumors were examined for configuration, limitation, contrast enhancement, and extent and signal intensity on MRI.ResultsThe mean age of the patients was 50.2 ± 16.7 years. Forty-two percent of the patients presented recurrent AFS (n = 5). Recurrences occurred 12 ± 6.5 months after tumor resection in the mean. Patients over 55 years of age showed a significantly higher risk for recurrences (RR = 5; 95% CI, 1.8 to 31; p = 0.04). Recurrent AFS was ovoid, nodular, streaky, polycyclic, or fascicular configured with homogeneous/heterogeneous contrast enhancement and well- or ill-defined borders. The intensity of contrast enhancement ranged from rim to marked contrast enhancement. Recurrent AFS mostly showed a muscle iso-intense signal in T1-weighted and a hyperintense signal in PD-weighted/TIRM sequences. The most common post-treatment changes were subcutaneous edema (92%; p = 0.03), muscle edema (75%), and postoperative seroma (50%). Patients with the presence of muscle edema after primary tumor resection had a slightly, but not significantly higher risk for recurrences (RR = 1.75; p = 0.08).ConclusionRecurrent AFS shows no common configuration on MRI, as it may appear ovoid, nodular, streaky, polycyclic, or fascicular. Patients with the presence of post-treatment muscle edema have a slightly higher risk for recurrences.Level of evidence: Level III, therapeutic study

Computed tomographic findings in a case of feline insulinoma

Insulinomas are functional insulin-secreting tumours of the beta cells of the pancreatic islets which are rare in cats. Clinical signs are a result of hypoglycaemia and include seizures, collapse, weakness,...