ABSTRACT
We present a rare case of solitary fibrous tumor (SFT) located in the intramedullary (IM) and intradural extramedullary sites of cervical spine, mimicking thrombosed aneurysm and meningioma. Herein, we present a case of spinal intradural SFT in a 59-year-old woman. She presented to the outpatient clinic with a right-sided motor weakness for over a year. The case was initially misinterpreted as a thrombosed aneurysm of the posterior spinal artery. Cervical spine magnetic resonance imaging revealed a well-circumscribed intradural mass with isosignal intensity on T1 and T2-weighted images with markedly T2 dark signal focus and homogenous intense enhancement at the level of C6. Computed tomography showed a slightly high-density mass without evidence of calcification or cystic component. Surgical removal was performed. However, due to combined IM component with adhesion, incomplete tumor resection was done. Pathologic analysis revealed hypocellular spindle cells with a thick collagenous stroma and immunohistochemical staining confirmed SFT. Spinal intradural SFT is a rare spindle cell tumor. Radiologists should consider SFT as a differential diagnosis if T2-weighted imaging shows an intradural located mass with markedly dark signal intensity focus.
ABSTRACT
MRI is a valuable imaging technique for the evaluation of intraarticular diseases. Accurate interpretation of joint MRI necessitates sound knowledge of anatomy. In the field of joint anatomy, in addition to the discovery of new structures, previously reported joint components of unexplained function are also detected. In this review, joint anatomy researched actively over the last decade is discussed. Joint components including the rotator cable and the superior capsule of the shoulder, posterolateral corner and the anterolateral ligament complex of the knee, and the distal tibiofibular syndesmosis of the ankle joint are introduced and correlated with their MRI features.
ABSTRACT
BACKGROUND AND OBJECTIVES: Recent evidence indicates that the membrane voltage and Ca2+ clocks jointly regulate sinoatrial node (SAN) automaticity. However, the mechanism of heart rhythm acceleration of the subsidiary pacemaker (SP) during beta-adrenergic stimulation is still unknown. Here we tested the hypothesis that the heart rate acceleration of the SP by beta-adrenergic stimulation involves synergistic interactions between both clock mechanisms. SUBJECTS AND METHODS: We performed optical mapping and pharmacological interventions in 15 isolated Langendorff-perfused canine right atriums (RA). The SP model was produced by ligation of the SAN artery at the mid portion of the sulcus terminalis. RESULTS: In the 6 RAs with an intact SAN, 1 micromol/L isoproterenol infusion increased the heart rate from 82+/-9 to 166+/-18 bpm (102%) with late diastolic Cai elevation (LDCAE) at the superior SAN. However, in the 6 SP models, the heart rate increased from 55+/-10 bpm to 106+/-11 bpm (92%, p=0.005) without LDCAE at the earliest activation site. The isoproterenol induced heart rate increase was reversed to 74+/-5 bpm (33% from baseline) by administering an infusion of the funny current blocker ZD 7288 (3 micromol/L, n=3), whereas, it was suppressed to 69+/-7 bpm (24% from baseline) by sarcoplasmic reticulum (SR) Ca2+ emptying with administering ryanodine (10 micromol/L) plus thapsigargin (200 nmol/L, n=3). The isoproterenol induced heart rate increase was completely abolished by combined treatment with funny current blocker and SR Ca2+ emptying (n=3). CONCLUSION: Acceleration of the Ca2+ clock in the SP plays an important role in the heart rate acceleration during beta-adrenergic stimulation, and this interacts synergistically with the voltage clock to increase the heart rate.