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Purpose: Acute ischemic stroke is one of the primary causes of death worldwide. Recent studies have shown that the assessment of collateral status could aid in improving the treatment for patients with acute ischemic stroke. We present a 3D deep regression neural network to automatically generate the collateral images from dynamic susceptibility contrast-enhanced magnetic resonance perfusion (DSC-MRP) in acute ischemic stroke., Methods: This retrospective study includes 144 subjects with acute ischemic stroke (stroke cases) and 201 subjects without acute ischemic stroke (controls). DSC-MRP images of these subjects were manually inspected for collateral assessment in arterial, capillary, early and late venous, and delay phases. The proposed network was trained on 205 subjects, and the optimal model was chosen using the validation set of 64 subjects. The predictive power of the network was assessed on the test set of 76 subjects using the squared correlation coefficient (R-squared), mean absolute error (MAE), Tanimoto measure (TM), and structural similarity index (SSIM)., Results: The proposed network was able to predict the five phase maps with high accuracy. On average, 0.897 R-squared, 0.581 × 10 -1 MAE, 0.946 TM, and 0.846 SSIM were achieved for the five phase maps. No statistically significant difference was, in general, found between controls and stroke cases. The performance of the proposed network was lower in the arterial and venous phases than the other three phases., Conclusion: The results suggested that the proposed network performs equally well for both control and acute ischemic stroke groups. The proposed network could help automate the assessment of collateral status in an efficient and effective manner and improve the quality and yield of diagnosis of acute ischemic stroke. The follow-up study will entail the clinical evaluation of the collateral images that are generated by the proposed network.

Metaplastic carcinoma is a rare subtype of breast cancer that comprises histologically diverse malignancies. Metaplastic carcinoma tends to have an aggressive clinical presentation, high metastatic potential, and more chances of local recurrence, as compared with intraductal carcinoma. Although many clinical and pathologic finding have been reported, to our knowledge, there are few reports of imaging findings for this type of tumor.In this study, we reviewed data of 5 patients with histopathologically proven metaplastic breast carcinoma. Multimodality imaging findings including those from mammography, ultrasonography, magnetic resonance imaging, and positron emission tomography-computed tomography were recorded.The results indicated that metaplastic carcinomas tend to show more benign imaging features such as round or oval shape with circumscribed margins and less axillary lymph node metastasis compared with invasive ductal carcinoma. High signal intensity on T2-weighted magnetic resonance imaging due to its cystic or necrotic component may be useful for diagnosis of metaplastic carcinoma.

Objective: Endometrial cancer is the most frequent cancer occurring in the female genital tract in the Western countries. Because surgical staging is currently the standard, noninvasive techniques that accurately identify lymph node (LN) metastases would be beneficial by reducing costs and complications. The purpose of our study is to compare the diagnostic accuracy of 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) with that of magnetic resonance imaging (MRI) for detecting LN metastases in the preoperative staging of endometrial cancer., Methods: Two hundred eighty-seven consecutive patients with endometrial cancer underwent preoperative PET/CT and MRI for staging. The malignancy criteria for LNs were a short diameter of 1 cm or more by MRI and focally increased (18)F-FDG uptake by PET/CT. After evaluating PET/CT and MRI separately, morphologic and functional image findings were compared with the histological findings regarding LN metastasis for all patients. PET/CT and MRI images were classified on the basis of histological findings as true-positive, true-negative, false-positive, or false-negative. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated., Results: Histologic examination revealed LN metastases in 51 patients (17.8%). The maximal standardized uptake values (SUVmax) of the primary lesions by PET/CT ranged from 1.4 to 37.7, with a mean value of 9.3, whereas those of the metastatic LNs ranged from 2.0 to 22.5 with a mean of 7.3. On a per-patient basis, node staging resulted in sensitivities of 70.0% with (18)F-FDG PET/CT and 34.0% with MRI, and specificities of 95.4 % with PET/CT and 95.0% with MRI. The NPV of PET/CT was 94.3%, and that of MRI was 87.2%. On a lesion base analysis, sensitivity of PET/CT was 79.4% while that of MRI was 51.6%. In detecting distant metastasis, the sensitivity, specificity, accuracy, PPV, and NPV of PET/CT were 92.9, 98.9, 98.6, 81.3, and 99.6%, respectively., Conclusion: Diagnostic performance of FDG PET/CT was better than MRI for detecting metastatic lymph nodes in patients with endometrial cancer both by patient basis and lesion basis analyses. Due to high NPV, FDG PET-CT could aid in selecting candidates for lymphadenectomy.

Objective: Solitary fibrous tumor (SFT) is a very rare tumor. The purpose of this study is to determine the MR imaging features of SFT in the intracranial and extracranial head and neck regions., Materials and Methods: We retrospectively reviewed six MR images and two CT images of six histologically proven cases of SFT that occurred in four men and two women, and their ages ranged from 46 to 59 years. These imaging findings were correlated with the microscopic findings of their surgical specimens., Results: Six SFTs arose in the meninges (the petrous ridge and the pituitary fossa), the parotid gland, the parapharyngeal space, the buccal space and the maxillary sinus. On the MR images, SFTs in the intracranial and extracranial head and neck regions were mostly isointense to the muscle on the T1-weighted images, they were hyperintense on the T2-weighted images and they all had intense enhancement. On the T1- and T2-weighted images, hypointense lines were observed within in five SFTs. On the CT images, the SFTs were hypodense to the muscle on the unenhanced images and they were heterogeneously enhanced on the contrast-enhanced images. An exceptional case of pituitary SFT was hypointense on the T2-weighted images and it was hyperdense on the unenhanced CT images, which correlated with the increased collagenous component and the cellular compactness., Conclusion: The imaging features of SFT are nonspecific; however, SFT should be included in the differential diagnosis of masses involving the intracranial and extracranial head and neck regions.

We report MR findings in a case of a giant cell reparative granuloma involving the temporal lobe in a middle-aged man. On MR images, most of the mass was hypointense on T1-weighted images, hypointense on T2-weighted images, and mildly enhanced on postcontrast T1-weighted images. The hypointensity on T2-weighted images corresponded to areas of hemorrhage and hemosiderin deposition on pathologic correlation.

Background and purpose We present a case of magnetic resonance imaging (MRI)-occult intracranial dural arteriovenous fistula (DAVF) with serious cervical myelopathy and review the pathophysiological background. Summary of case A 61-year-old man had suffered from progressive neurological deterioration. He had demonstrated swollen spinal cord with diffuse enhancement and no dilated vascularity on MRI. Finally, digital subtraction angiography revealed DAVF at the petrous ridge and it was successfully treated by embolization. Conclusion A slow flow DAVF is not readily recognizable on MRI. Whenever a patient presents with unexplainable progressive myelopathy, a possibility of vascular origin has to be considered. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Acetazolamide-challenged perfusion magnetic resonance imaging (MRI) has been shown as a method for assessment of cerebrovascular reserve (CVR) capacity in patients with atherosclerotic steno-occlusive disease of internal carotid artery. We have assessed the feasibility of the acetazolamide-challenged perfusion MRI for evaluating CVR in symptomatic patients with severe middle cerebral artery (MCA) stenosis (≥70%) by comparison with the acetazolamide-challenged technetium-99m-hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography (SPECT). Methods: Seventeen prospectively enrolled patients with symptomatic unilateral MCA stenosis underwent technetium-99m-hexamethylpropyleneamine oxime SPECT and perfusion MRI without and with acetazolamide challenge, respectively. Acetazolamide-challenged SPECT and perfusion MRI were compared quantitatively by Region of interest (ROI) analysis. Results: At all ROIs, there were no significant differences in percent change between SPECT and perfusion MRI. Patients with impaired CVR showed significant decreases in the percent changes of respective cerebral blood flow (P=.016) and respective cerebral blood volume (P=.029). Conclusion: Acetazolamide-challenged perfusion MRI is feasible for evaluating CVR in symptomatic patients with severe MCA stenosis quantitatively. [Copyright &y& Elsevier]

Abstract: Background context: The ligamentum flavum may undergo various pathologic changes, including hypertrophy, calcification, ossification, and cyst formation. Ligamentum flavum hematoma (LFH) is a rare cause of spinal nerve root or cord compression and usually occurs in the lumbar spine. We report a 66-year-old woman with LFH occurring after an epidural block, mimicking epidural hematoma on lumbar spine magnetic resonance imaging (MRI). Purpose: To document MRI findings of epidural block–induced LFH mimicking epidural hematoma. Study design/setting: A case report. Methods: A 66-year-old woman presented with a 6-month history of pain in the left buttock and suffered abrupt weakness and numbness in her left leg after an epidural block procedure without any other trauma history. Lumbar spine MRI with enhancement showed a hematoma-like mass in the posterior epidural space at L3–L4 level. Results: The patient underwent a left hemilaminectomy at the L3 level, and a surgeon found a small hematoma between inner and outer walls of ligamentum flavum instead of an epidural hematoma and performed the removal of the hypertrophied ligamentum flavum including the intraligamentary lesion. Histopathologic examination confirmed the lesion as hematoma in the left ligamentum flavum. After surgery, the patient recovered without significant neurologic deficit. Conclusions: Epidural block–induced LFH can mimic posterior epidural hematoma on MRI. Careful evaluation of hematoma, location, and imaging findings is required for accurate diagnosis. [Copyright &y& Elsevier]