Contrast-enhanced 3D black-blood magnetic resonance imaging for diagnosis of cerebral venous thrombosis.

PURPOSE: Cerebral venous thrombosis (CVT) is often under-recognized on routine magnetic resonance imaging (MRI) examinations without concomitant magnetic resonance venography (MRV). Contrast-enhanced black-blood MRI (BBMRI) based on a three-dimensional T1-weighted variable-flip-angle turbo spin echo sequence, one of the sequences used routinely in our practice, has the potential for detection of thrombi in patients with CVT. The aim of this study is to evaluate the diagnostic performance and enhancement patterns of contrast-enhanced three-dimensional BBMRI for the diagnosis of CVT. MATERIALS AND METHODS: Contrast-enhanced BBMRI and contrast-enhanced MRV sequences of 64 patients, acquired from June 2018 to January 2021, were retrospectively reviewed by neuroradiologists for detection of CVT in each venous sinus segment. Diagnostic performance values were calculated for contrast-enhanced BBMRI based on enhancement patterns. RESULTS: Of 749 venous segments from 64 patients analyzed, CVT was demonstrated in 41 venous segments from 12 patients on contrast-enhanced MRV (CE MRV). Thick wall enhancement and total enhancement patterns were dominantly demonstrated in thrombosed segments. Compared with contrast-enhanced MRV, contrast-enhanced BBMRI had a patient-based sensitivity and specificity of 100% and 98.1%, respectively, and a segment-based sensitivity and specificity of 87.8% and 96.2%, respectively. The positive predictive value of contrast-enhanced BBMRI in detecting CVT was 92.3% (patient-based) and 57.1% (segment-based), and the negative predictive value was 100% (patient-based) and 99.3% (segment-based). CONCLUSION: Contrast-enhanced BBMRI has high diagnostic performance in detection and diagnosis of CVT. This sequence may be useful to recognize CVT when dedicated CE MRV was not performed in patients with nonspecific neurological symptoms.

Intravoxel incoherent motion for differentiating residual/recurrent tumor from post-treatment change in patients with high-grade glioma.

PURPOSE: To investigate the diagnostic value of f derived from IVIM technique and to correlate it with rCBV derived from DSC for the differentiation of residual/recurrent tumor from post-treatment change in patients with high-grade glioma. MATERIALS AND METHODS: Patients who underwent MR imaging with IVIM and DSC studies for evaluation of high-grade glioma after standard treatment were enrolled in this retrospective study. For qualitative analysis, the f and rCBV maps were interpreted as hypoperfused or hyperperfused in each parameter. Quantitative analysis was performed using ROI analysis in f and rCBV parameters. The lesions were divided into residual/recurrent tumor and post-treatment change groups. RESULTS: Nineteen patients with high-grade glioma were included. In qualitative analysis, the f-map shows higher sensitivity (100.0%) than rCBV map (92.3%), while the rCBV map shows higher specificity (100.0%) than the f-map (83.3%). In quantitative analysis, the optimal cutoff values of 1.19 for f and 1.06 for rCBV are shown to provide high diagnostic value with high sensitivity (91.7%) for both parameters but slightly higher specificity of rCBV (85.7%) than f (71.4%). The correlation between f and rCBV was good with ICC of 0.810. CONCLUSION: The f value measured by IVIM technique, non-contrast perfusion technique, has high diagnostic performance and potential to be an alternative method to CBV measured by DSC for differentiation between residual/recurrent tumor and post-treatment change in patients with high-grade glioma.

Dual-Energy Computed Tomography-Derived Iodine Density and Spectral Attenuation Analysis for Differentiation of Inverted Papilloma and Sinonasal Squamous Cell Carcinoma/Lymphoma.

OBJECTIVE: This study aimed to assess the value of dual-energy computed tomography for differentiation of inverted papilloma from squamous cell carcinoma (SCC)/lymphoma. METHODS: Twenty-eight patients with pathologically diagnosed inverted papilloma or SCC/lymphoma underwent contrast-enhanced dual-energy computed tomography. Qualitative features (laterality, location, enhancement pattern, border, necrosis, hemorrhage, calcification, bone destruction, pterygopalatine fossa extension, adjacent invasion, and perineural spreading) and quantitative features (iodine density and spectral attenuation curve slope) were analyzed. Optimal cutoff thresholds of diagnostic efficacy were generated. RESULTS: Fifteen patients had inverted papilloma, and 13 had malignancy (5 SCC and 8 lymphoma). Computed tomography findings of bilateral lesions, sphenoid sinus involvement, pterygopalatine fossa extension, and adjacent invasion were significantly associated with SCC/lymphoma. The iodine density was significantly higher in SCC/lymphoma (2.46 ± 0.22 mg/mL) than in inverted papilloma (1.42 ± 0.46 mg/mL; P = 0.001). An iodine density threshold of 1.74 mg/mL had a sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of 92.3%, 86.7%, 92.9%, 85.7%, and 90.3%, respectively. The spectral attenuation curve slope was significantly higher in SCC/lymphoma (4.35 ± 0.27 HU/keV) than in inverted papilloma (2.72 ± 0.88 HU/keV; P = 0.001). A spectral attenuation curve slope threshold of 3.34 HU/keV had a sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of 92.3%, 86.7%, 92.9%, 85.7%, and 90.8%, respectively. CONCLUSIONS: Squamous cell carcinoma/lymphoma had a significantly higher iodine density and spectral attenuation curve slope than inverted papilloma. Using optimal quantitative measurement thresholds provides high diagnostic efficacy.

Enlarging biopsy-proven fibroadenoma: Is surgical excision necessary?

PURPOSE: Core biopsy-proven fibroadenomas that enlarge on clinical or imaging follow-up are often surgically excised to exclude an associated malignancy. The purpose of this study was to assess how often malignancy is detected upon excision, and to determine whether excision of enlarging, biopsy-proven, uncomplicated fibroadenomas is still warranted. MATERIALS AND METHODS: Review of our institutional pathology database from 2000 to 2010 identified 1117 cases of fibroadenoma, and retrospective chart review, including review of pathology and imaging findings of all these records, was performed. RESULTS: 1117 cases of fibroadenoma were identified in a population of women ranging from ages 17 to 78. Of these, 378 (33.8%) were diagnosed by ultrasound core needle biopsy and formed the study population. Of the 378 cases, 24 (6.3%) had co-existent atypia and were immediately excised; these cases were excluded. An additional 107 (28%) were lost to follow-up. Of the remaining 247 cases, 201 (81%) showed stability on follow-up imaging (mean 31.5 months), and 46 (18.6%) enlarged on follow-up. Of the 46 biopsy proven fibroadenomas that enlarged, 19 had a biopsy at initial presentation and 27 underwent biopsy after they enlarged. Seventeen of the 19 were excised after enlargement, and pathology confirmed fibroadenoma in all cases (100%); two enlarged on initial follow-up imaging but remained stable for at least three years on continued follow-up. Of the 27 cases which were biopsied after enlargement, 23 revealed fibroadenoma on core biopsy, 3 had fibroadenoma with associated atypia with subsequent surgery revealing fibroadenoma and no associated malignancy, and one showed fibroadenoma with smooth muscle with subsequent surgery showing phyllodes tumor. CONCLUSION: Based on this study, enlarging biopsy proven fibroadenomas are not associated with malignancy; therefore, surgical excision does not seem warranted. For presumed enlarging fibroadenomas on imaging, core biopsy should be performed to exclude associated atypia or phyllodes tumor. Finally, surgical excision is indicated for lesions with associated atypia or suspected phyllodes and for symptomatic lesions or cosmetic reasons.

Neuroimaging in Pregnant Women.

Choosing the most appropriate diagnostic neuroimaging study for a pregnant woman involves assessing the pretest likelihood of serious treatable neurologic disease, the diagnostic utility of various available computed tomography (CT) and magnetic resonance (MR) modalities, and the risks of each. Of these three elements-pretest differential diagnosis, utility of MRI and CT, and risks of MR and CT-the risk component is perhaps the least well understood by most physicians. We provide a basic review of the intrinsic risks of MRI and CT, particularly radiation biology and radiation safety, as well as the risks pertaining to the use of contrast agents, to reduce provider confusion and anxiety and improve quality, safety, and efficiency of neuroimaging diagnosis in pregnant patients. We believe that a better understanding of the associated very low risks with mother and fetus will reassure the reader that CT remains the most appropriate tool for initial rapid diagnosis of acute neurological conditions in pregnancy and that in urgent situations CT should not be withheld or delayed due to exaggerated concern about radiation. Noncontrast MRI, while not without risk, is generally considered safe in pregnancy, as no evidence of fetal adverse effects has been demonstrated to date. Iodinated CT contrast agents are likely safer than gadolinium-based MRI contrast agents because of gadolinium accumulation in the amniotic fluid and fetal tissue, although no harmful effects of tissue gadolinium accumulation are known. In most but not all pregnant patients presenting with a new or worsening neurological abnormality, the risks intrinsic to the disease will outweigh the risks of imaging. In an individual patient, the pretest probability of serious treatable disease and acuity of presentation will usually suggest an optimal imaging strategy and choice of test. This optimal strategy will also depend on the immediate availability and level of sophistication of the scanners, software, technologists, and radiologists. As such, the standard of care for imaging in pregnancy requires direct consultation between the referring clinician and radiologist to determine the most appropriate strategy and brief documentation of the resulting consensus risk-benefit assessment.

Interventional MR Imaging for Deep-Brain Stimulation Electrode Placement.

Purpose To investigate the safety and targeting errors of deep-brain stimulation (DBS) electrodes placed under interventional magnetic resonance (MR) imaging, which allows near real-time anatomic placement without physiologic mapping. Materials and Methods Retrospectively evaluated were 10 consecutive patients (five women, five men) with a mean age of 59.9 years (age range, 17-79 years). These patients underwent interventional MR imaging-guided DBS placement for movement disorders from September 2013 to August 2014 for placement of 19 DBS electrodes in cases where traditional frame-based surgery may be challenging because of the following: dystonia resulting in difficulty in placing the patients in frame, patient's inability or unwillingness to tolerate awake surgery, or anatomic anomaly or variant that could increase the risk of bleeding from microelectrode mapping. Outcomes measured included perioperative hemorrhage, death, and stroke, and electrode functionality assessed at 2 weeks after the operation. In addition, the mean radial error and mean trajectory error were calculated. Results No intraoperative neurologic complications (n = 10 [95% confidence interval: 0%, 31%]) were observed. One patient developed aspiration pneumonia in the postoperative period. Mean radial error was 0.7 mm ± 0.4 (standard deviation) and mean trajectory error was 0.5 mm ± 0.4. All leads delivered clinically effective stimulation. Conclusion Interventional MR imaging-guided DBS electrode placement may be a safe and effective alternative to conventional frame-based surgery in well-selected patients. © RSNA, 2016.

Magnetic Resonance Imaging-Guided Spine Interventions.

MR imaging-guided interventions for treatment of low back pain and for diagnosis and treatment of soft tissue and bony spinal lesions have been shown to be feasible, effective, and safe. Advantages of this technique include the absence of ionizing radiation, the high tissue contrast, and multiplanar imaging options. Recent advancements in MR imaging systems allow improved image qualities and real-time guidance. One exciting application is MR imaging-guided cryotherapy of spinal lesions, including treating such lesions as benign osteoid osteomas and malignant metastatic disease in patients who are not good surgical candidates. This particular technique shows promise for local tumor control and pain relief in appropriate patients.

Intra-thoracic rheumatoid arthritis: Imaging spectrum of typical findings and treatment related complications.

Non-cardiac thoracic manifestations of rheumatoid arthritis (RA) cause significant morbidity and mortality among RA patients. Essentially all anatomic compartments in the chest can be affected including the pleura, pulmonary parenchyma, airway, and vasculature. In addition, treatment-related complications and opportunistic infections are not uncommon. Accurate diagnosis of intra-thoracic disease in an RA patient can be difficult as the radiologic findings may be nonspecific and many of these conditions may coexist. This review article serves to highlight the multitude of RA-related intra-thoracic pathological processes, emphasize differential diagnosis, diagnostic conundrums and discuss how tailoring of CT imaging and image-guided biopsy plays a key role in the management of RA-related pulmonary disease.

Imaging in lung transplants: Checklist for the radiologist.

Post lung transplant complications can have overlapping clinical and imaging features, and hence, the time point at which they occur is a key distinguisher. Complications of lung transplantation may occur along a continuum in the immediate or longer postoperative period, including surgical and mechanical problems due to size mismatch and vascular as well as airway anastomotic complication, injuries from ischemia and reperfusion, acute and chronic rejection, pulmonary infections, and post-transplantation lymphoproliferative disorder. Life expectancy after lung transplantation has been limited primarily by chronic rejection and infection. Multiple detector computed tomography (MDCT) is critical for evaluation and early diagnosis of complications to enable selection of effective therapy and decrease morbidity and mortality among lung transplant recipients.

Hyaluronic acid-binding scaffold for articular cartilage repair.

Hyaluronic acid (HA) is an extracellular matrix molecule with multiple physical and biological functions found in many tissues, including cartilage. HA has been incorporated in a number of biomaterial and scaffold systems. However, HA in the material may be difficult to control if it is not chemically modified and chemical modification of HA may negatively impact biological function. In this study, we developed a poly(ethylene glycol) hydrogel with noncovalent HA-binding capabilities and evaluated its ability to support cartilage formation in vitro and in an articular defect model. Chondrogenic differentiation of mesenchymal stem cells encapsulated in the HA-interactive scaffolds containing various amounts of exogenous HA was evaluated. The HA-binding hydrogel without exogenous HA produced the best cartilage as determined by biochemical content (glysocaminoglycan and collagen), histology (Safranin O and type II collagen staining), and gene expression analysis for aggrecan, type I collagen, type II collagen, and sox-9. This HA-binding formulation was then translated to an osteochondral defect model in the rat knee. After 6 weeks, histological analysis demonstrated improved cartilage tissue production in defects treated with the HA-interactive hydrogel compared to noninteractive control scaffolds and untreated defects. In addition to the tissue repair in the defect space, the Safranin O staining in cartilage tissue surrounding the defect was greater in treatment groups where the HA-binding scaffold was applied. In sum, incorporation of a noncovalent HA-binding functionality into biomaterials provides an ability to interact with local or exogenous HA, which can then impact tissue remodeling and ultimately new tissue production.

The postconservation breast: part 1, Expected imaging findings.

OBJECTIVE: The objectives of this article are to discuss the conventional imaging algorithms after breast-conserving surgery and radiation therapy and to review the expected chronologic imaging appearances of the conservatively treated breast. CONCLUSION: Imaging the treated breast presents challenges because of its limited compressibility and the overlapping features of benign posttreatment alterations and tumor recurrence. After lumpectomy and radiation therapy, mammographic findings such as breast edema, skin thickening, fluid collections, architectural distortion, and calcifications have characteristic sequences of evolution toward stability. Awareness of these normal chronologic imaging findings for the conservatively treated breast minimizes unnecessary recall from screening and permits early detection of recurrent breast carcinoma.

The postconservation breast: part 2, Imaging findings of tumor recurrence and other long-term sequelae.

OBJECTIVE: The objectives of this article are to highlight the imaging findings of tumor recurrence and other long-term potential sequelae after breast-conserving surgery and radiation therapy, including increased risk of infection and radiation-induced malignancies. The role of MRI as a problem-solving tool in evaluating the conservatively treated breast will also be discussed. CONCLUSION: Imaging the treated breast presents challenges because of its limited compressibility and overlapping features of benign posttreatment alterations and tumor recurrence. After lumpectomy and radiation therapy, mammographic findings such as breast edema, skin thickening, fluid collections, architectural distortion, and calcifications have characteristic sequences of evolution toward stability. Changes in the imaging appearance after stability has been achieved--including increasing asymmetry, an enlarging mass, increasing edema or skin thickening, and the development of pleomorphic calcifications within or near the operative bed--should alert the radiologist to possible tumor recurrence. When mammography or sonography is indeterminate, MRI may be useful in excluding recurrence or providing a means for biopsy of a suspicious finding.

Enhanced chondrogenesis of mesenchymal stem cells in collagen mimetic peptide-mediated microenvironment.

A new type of synthetic hydrogel scaffold that mimics certain aspects of structure and function of natural extracellular matrix (ECM) has been developed. We previously reported the conjugation of collagen mimetic peptide (CMP) to poly(ethylene oxide) diacrylate (PEODA) to create a polymer-peptide hybrid scaffold for a suitable cell microenvironment. In this study, we showed that the CMP-mediated microenvironment enhances the chondrogenic differentiation of mesenchymal stem cells (MSCs). MSCs were harvested and photo-encapsulated in CMP-conjugated PEODA (CMP/PEODA). After 3 weeks, the histological and biochemical analysis of the CMP/PEODA gel revealed twice as much glycosaminoglycan and collagen contents as in control PEODA hydrogels. Moreover, MSCs cultured in CMP/PEODA hydrogel exhibited a lower level of hypertrophic markers, core binding factor alpha 1, and type X collagen than MSCs in PEODA hydrogel as revealed by gene expression and immunohistochemisty. These results indicate that CMP/PEODA hydrogel provides a favorable microenvironment for encapsulated MSCs and regulates their downstream chondrogenic differentiation.

Enhanced chondrogenic differentiation of embryonic stem cells by coculture with hepatic cells.

Enhancing the specific differentiation of pluripotent embryonic stem (ES) cells has been a challenge in the field of tissue engineering. Previously, hepatic cells have been shown to secrete various soluble morphogenic factors to direct mesodermal differentiation of ES cells. In this study, we hypothesized that factors secreted by hepatic cells possess chondrogenic-differentiating effects, and, therefore, the co-culture of hepatic cells would enhance chondrogenesis of ES cells. ES-derived cells(ESDCs) were co-cultured with hepatic cells (HEPA-1C1c7) in three-dimensional bilayered hydrogels. After 3 weeks culture, the histological and biochemical analysis of the HEPA-co-cultured ESDCs revealed a four-fold increase in glycosaminoglycan (GAG) compared to ESDCs cultured alone. This result was supported by real-time PCR analysis, which demonstrated an 80-fold increase in aggrecan expression in co-cultured ESDCs. Additionally, type IIB collagen expression was observed only with co-cultured ESDCs, and immunohistochemical analysis resulted in significantly more positive type II collagen staining with co-cultured ESDCs. Moreover, at day 21, gene expression of other lineages in HEPA-co-cultured ESDCs was either comparable to or lower than those of ESDCs cultured alone. These results indicated that co-culture of ESDCs with hepatic cells significantly enhanced specific chondrogenic differentiation of ESDCs.

Collagen mimetic peptide-conjugated photopolymerizable PEG hydrogel.

Collagen mimetic peptide (CMP) with a specific amino acid sequence, -(Pro-Hyp-Gly)(x)-, forms a triple helix conformation that resembles the native protein structure of natural collagens. CMP previously has been shown to associate with type I collagen molecules and fibers via a strand invasion process. We hypothesized that when poly(ethylene glycol) (PEG) hydrogel, a non-adhesive tissue engineering scaffold, is conjugated with CMP, it may retain cell-secreted collagens and also form physical crosslinks that can be manipulated by cells. A photopolymerizable CMP derivative was synthesized and copolymerized with poly(ethylene oxide) diacrylate to create a novel PEG hydrogel. In a model retention experiment, diffusional loss of type I collagen that was added to the hydrogel was limited. Chondrocytes were encapsulated in the hydrogel to examine its use as a tissue engineering scaffold. After 2 weeks, the biochemical analysis of the CMP-conjugated PEG gel revealed an 87% increase in glycosaminoglycan content and a 103% increase in collagen content compared to that of control PEG hydrogels. The histology and immunohistochemistry analyses also showed increased staining of extracellular matrix. These results indicate that the CMP enhances the tissue production of cells encapsulated in the PEG hydrogel by providing cell-manipulated crosslinks and collagen binding sites that simulate natural extracellular matrix.