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Purpose: To investigate the utility of palmar bowing of the flexor retinaculum (PBFR) on magnetic resonance imaging (MRI) as an adjunct to presurgical evaluation of carpal tunnel syndrome (CTS)., Materials and Methods: The CTS group comprised 48 women with CTS diagnosed from clinical history, physical examination, and electrophysiological findings. Another 21 healthy women with no symptoms of CTS served as controls. The CTS group was divided into four subgroups based on symptom duration. CTS patients were preoperatively assessed for symptom severity using a Likert scale. In both groups, palmar bowing of the flexor retinaculum (PBFR) was measured on MRI. Furthermore, relationships with disease duration, subjective symptom severity, and electrophysiological findings were assessed in the CTS group., Results: Although PBFR increased significantly in all CTS groups when compared to the control group, PBFR in patients who complained of severe pain tended to exceed that in patients with mild to moderate pain. Statistical analysis showed a positive correlation between PBFR and pain severity. In contrast, PBFR did not reflect median nerve function., Conclusion: PBFR as seen on MRI seems to correlate significantly with patients' subjective reports of pain severity.

Subchondral insufficiency fracture of the femoral head is a rarely reported lesion, often confused with osteonecrosis, transient osteoporosis of the hip, or rapidly destructive coxarthrosis. However, almost all the previous reports about this lesion have documented unilateral cases. We report the clinical and histological features of bilateral subchondral insufficiency fracture of the femoral head in a 68-year-old woman. She reported a sudden pain in her left hip without apparent trauma. An anteroposterior radiograph 2 weeks after the onset of pain in the left hip shows a subchondral collapse of the femoral head. The entire femoral head was depicted as a low intensity area on a T1-weighted image, and there was a subchondral linear pattern of low signal intensity with a convex shape to the articular surface. On T2-weighted image, the entire femoral head was depicted as a high intensity area, and on T1-weighted image, a linear low signal intensity pattern was noted. The patient underwent hemiarthroplasty. Cross-section of the femoral head showed a fracture line identified in the subchondral area. Although the patient's postoperative course was favorable, she had idiopathic pain in the right hip. A lateral radiograph 3 weeks after the onset of pain in the right hip shows irregularity at the surface of the femoral head. Cross-section of the right femoral head showed a concave fracture line in the subchondral bone. Based on these findings, bilateral subchondral insufficiency fracture of the femoral head was diagnosed.

We recently experienced 4 cases of intramuscular myxoma and analyzed MRI findings, comparing them with histological ones. Results showed that all tumors were depicted with a homogeneous low signal intensity on T1-weighted images and a markedly high signal intensity on T2-weighted images, findings which are similar to those of cystic lesions like intramuscular ganglions. However, tumors were diffusely and finely enhanced on T1-weighted images with intravenous gadolinium administration. Three cases showed the characteristic fat rim and fat cap. A diffuse edematous lesion demonstrating intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images was also found in the adjacent muscle surrounding the tumor in 3 of 4 cases. In this lesion, tumor invasion, diffuse and severe muscle degeneration, blood and lymphatic congestion with exudates, and reactive adipose tissue formation were observed. The present results suggested that for the clinical diagnosis of intramuscular myxoma with MRI examination, the combination of three MRI signs such as homogeneous low signal intensity on T1-weighted mages, markedly high signal intensity on T2-weighted images, and an enhancement effect with contrast medium are important, but the fat rim or fat cap, and the surrounding muscle edema as detected by MRI are also characteristic and allow for a more firm diagnosis. We presume that the diffuse and severe muscle fiber degeneration induced by tumors may cause such specific surrounding muscle edema.

We recently encountered a case with local recurrence of malignant fibrous histiocytoma (MFH) in the bone after wide resection, caused by minute intravenous tumor emboli which were retrospectively detected in MR imaging. The patient was a 69-year-old woman who initially noticed a mass in her left thigh. The tumor was diagnosed to be MFH, therefore a wide resection was performed; although the tumor was closely attached to the periosteum, it was not difficult to dissect the tumor subperiosteally from the cortex of the femur. The patient received postoperative brachytherapy, but no chemotherapy. Two years later, the tumor recurred with bony destruction of the femur. We reviewed the pre-operative films obtained by various imaging modalities, as well as the histology of the primary tumor, and found minute intravenous tumor emboli in the MR imaging obtained before surgery. Tumor emboli were also observed histologically in the small vessels of the surgically resected tumor. Such intravenous tumor emboli have recently been implicated in the development of regional bone metastasis near the site of the primary lesion in cases of malignant soft tissue tumors. Therefore, we concluded that the tumor recurrence in our case was caused by small tumor emboli invading the perforating veins of the femur. It is therefore emphasized that MR images should be carefully reviewed for the presence of such intravenous tumor emboli before surgery in cases of high-grade malignant sarcomas. As at the time of writing, our patient remains alive and disease-free, with no evidence of any local recurrence or distant metastasis after wide tumor resection for the recurrent tumor.

Purpose: Recent studies have shown that low-intensity resistance training with vascular occlusion (kaatsu training) induces muscle hypertrophy. A local hypoxic environment facilitates muscle hypertrophy during kaatsu training. We postulated that muscle hypertrophy can be more efficiently induced by placing the entire body in a hypoxic environment to induce muscle hypoxia followed by resistance training. Methods: Fourteen male university students were randomly assigned to hypoxia (Hyp) and normoxia (Norm) groups (n = 7 per group). Each training session proceeded at an exercise intensity of 70% of 1 repetition maximum (RM), and comprised four sets of 10 repetitions of elbow extension and flexion. Students exercised twice weekly for 6 wk and then muscle hypertrophy was assessed by magnetic resonance imaging and muscle strength was evaluated based on 1RM. Results: Muscle hypertrophy was significantly greater for the Hyp-Ex (exercised flexor of the hypoxia group) than for the Hyp-N (nonexercised flexor of the hypoxia group) or Norm-Ex flexor (P < .05, Bonferroni correction). Muscle hypertrophy was significantly greater for the Hyp-Ex than the Hyp-N extensor. Muscle strength was significantly increased early (by week 3) in the Hyp-Ex, but not in the Norm- Ex group. Conclusion: This study suggests that resistance training under hypoxic conditions improves muscle strength and induces muscle hypertrophy faster than under normoxic conditions, thus representing a promising new training technique. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the study is to assess the orientation and distance of the popliteal artery (PA) from both the anteromedial and anterolateral portals. Methods: The records of 97 patients (100 knees) who underwent knee arthroscopy were reviewed. The shortest distance from the posterior tibial cortex to the PA on the lines from both the medial and lateral borders of the patellar tendon to the PA was evaluated by magnetic resonance imaging at full knee extension. The figure-of-four position was compared between patients with intact and deficient anterior cruciate ligaments (ACLs). The shortest distances from the posterior cruciate ligament (PCL) to the lines running from the medial and lateral borders of the patellar tendon to the PA were also measured. Results: The shortest distances from the posterior tibial cortex to the PA were significantly longer in the figure-of-four position than at full knee extension and during extension in the ACL-deficient than intact group. Distances did not significantly differ in the figure-of-four position. The PA was hidden from the anteromedial portal by the PCL, but remained vulnerable from the anterolateral portal. Conclusions: All-inside meniscus suturing of the posterior horn of the lateral meniscus inserted through the anteromedial portal is safer when the knee is in the figure-of-four position than fully extended. Meniscus repairs should be completed before ACL reconstruction due to vascular positions and the ease of approach. Level of evidence: Prospective correlation study, Level IV. [ABSTRACT FROM AUTHOR]

Abstract: We report a case of idiopathic spinal cord herniation through the inner layer of duplicated anterior dura. High-resolution three-dimensional (3D) MRIs clearly depicted the duplicated dura mater ventral to the spinal cord and herniation of the cord through the inner layer of dura mater, which was confirmed at surgery. Presurgical high-resolution 3D MRI thus enables precise determination of the site of cord herniation in patients with this condition. [Copyright &y& Elsevier]

Freiberg’s infraction is a rare disorder that arises mostly in adolescent athletes. We describe a 77-year-old woman with the collapse of second metatarsal head with similar clinical appearance to Freiberg’s infraction. Radiological findings at initial visit of our hospital were normal. Her condition was obscure and magnetic resonance imaging showed the subchondral insufficiency fracture with bone marrow edema to the second metatarsal head. Despite the conservative treatment, the second metatarsal head collapsed. She was surgically treated with an osteochondral autograft without complications relating surgery. Furthermore, the histological findings showed that the site of collapse was considered to be secondary lesions resulting from the subchondral insufficiency fracture. [ABSTRACT FROM AUTHOR]

The article describes the case of a 47-year-old woman who presented a ganglion cyst arising from the posterolateral capsule of the knee. She did not have a history of trauma or participation in active sports. An intra-articular ganglion cyst of the knee has the same symptoms with meniscus tears such as pain, swelling and mechanical blocking. According to the article, magnetic resonance imaging has been proven to be effective in evaluating cystic lesions of the knee.