Ryo Miyagi

Skeletal Age Assessment in Children Using an Open Compact MRI System

MRI may be a noninvasive and alternative tool for skeletal age assessment in children, although few studies have reported on this topic. In this article, skeletal age was assessed over a wide range of ages using an open, compact MRI optimized for the imaging of a childs hand and wrist, and its validity was evaluated. MR images and their three‐dimensional segmentation visualized detailed skeletal features of each bone in the hand and wrist. Skeletal age was then independently scored from the MR images by two raters, according to the Tanner–Whitehouse Japan system. The skeletal age assessed by MR rating demonstrated a strong positive correlation with chronological age. The intrarater and inter‐rater reproducibilities were significantly high. These results demonstrate the validity and reliability of skeletal age assessment using MRI. Magn Reson Med, 2013.

Comparison Between High-Resolution Isotropic Three-Dimensional and High-Resolution Conventional Two-Dimensional FSE MR Images of the Wrist at 3 Tesla: A Pilot Study

To demonstrate the clinical feasibility of high‐resolution three‐dimensional (3D) isotropic FSE MRI of the wrist by comparing it to high‐resolution conventional 2D FSE (2D) MRI.

Complete Resolution of a Case of Calcific Tendinitis of the Longus Colli with Conservative Treatment

Acute calcific tendinitis of the longuscolli is a self-limiting inflammatory condition caused by calcium hydroxyapatite deposition in the longuscolli tendon. Although several case reports have described its radiological presentation, few reports provide detailed chronological accounts through symptomatic and radiologic resolution. A 59-year-old woman presented with severe neck pain and stiffness of a few days duration as well as moderate discomfort when swallowing. Lateral radiographs revealed a large calcium deposit anterior to the C1.C2 joint and swelling of the prevertebral soft tissue from C1 to C5. CT and magnetic resonance imaging showed fluid in the retropharyngeal gap.A soft collar and non-steroidal anti-inflammatory drug were prescribed, without antibiotics. At 4 months after presentation, the calcium deposit and all symptoms had resolved completely. Although this disease is comparatively rare, physicians should keep it in mind when a patient presents with acute severe neck pain.

Clinical outcomes of spinal surgery in patients treated with hemodialysis.

Study Design: Retrospective study. Objective: The purpose of this study is to review clinical outcomes, including survival rate, and to discuss the potential benefit of surgical treatments for spinal disorders in patients treated with long-term hemodialysis (HD). Summary of Background Data: Long-term HD is known to possibly cause destructive spondyloarthropathy (DSA) with spinal canal stenosis. There have been few reports, however, regarding clinical outcomes and patient survival rates after spinal surgeries in this population. Methods: We retrospectively reviewed 33 chronic HD patients who underwent 21 cervical and 13 lumbar spinal surgeries. According to the radiologic findings, we divided them into the non-DSA and the DSA groups. In general, only decompression was performed for the non-DSA patients, whereas spinal fusion was added for the DSA patients. We analyzed the following data, respectively: male-female ratio, age, operative time, estimated blood loss, duration of HD, follow-up duration, preoperative and postoperative Japanese Orthopaedic Association score, improvement ratio of the Japanese Orthopaedic Association score, amyloid deposition characteristics, and survival rate. Results: All patients improved neurologically and functionally after surgery. There were significant differences in the operative time between the DSA and the non-DSA groups in patients with cervical spinal lesions, whereas in patients with lumbar spinal lesions, there were significant differences in sex, operative time, and estimated blood loss. Amyloid deposition was found signficantly more commonly in DSA than in non-DSA patients and was associated with a longer duration of HD. Nine patients died within 49 months of the surgery because of HD-related complications, but there was no surgery-related morbidity. Kaplan-Meier analysis showed a trend toward decreased survival rate in non-DSA patients more than 40 months after the index surgery. Conclusions: Even in patients treated with long-term HD, spinal surgeries reliably obtain neurological and functional improvement if surgeons judge the preoperative inclusion criteria correctly. However, if surgeries are necessary for these patients, surgeons should consider the patients’ comorbidity-related survival rate after the spinal surgeries.

Study of surgical indication for knee arthroplasty by cartilage analysis in three compartments using data from Osteoarthritis Initiative (OAI).

BackgroundBicompartmental or unicompartmental knee arthroplasty (BKA, UKA) is currently advocated as an alternative solution to conventional total knee arthroplasty (TKA) in order to preserve bone stock and ligaments for limited osteoarthritis (OA) with intact anterior and posterior cruciate ligaments (ACL, PCL). However, the actual rate of UKA or BKA compared to TKA procedures in OA patients has not been reported. In this study, we retrospectively analyzed preoperative MRI of the knee in subjects who underwent knee arthroplasty and assessed the potential for UKA or BKA as an alternative treatment.MethodsData were extracted from the Osteoarthritis Initiative (OAI) public use data set, which included 4,796 subjects, ages 45–79. 3.0 Tesla MRI scanners were dedicated to imaging the knees of OAI participants annually from February 2004 to March 2010. Extensive quantitative measurements of the knee MRI were performed on 87 patients who underwent knee arthroplasty during follow-up visits. We assessed the cartilage thickness and defect size in the medial femorotibial joint (FTJ), lateral FTJ, and patellofemoral joint (PFJ) as well as ligamentous injury, bone marrow edema, and subchondral cyst size from 2D coronal turbo spin echo (TSE), 2D sagittal TSE, 3D coronal T1-weighted water-excitation fast low angle shot (FLASH), and 3D sagittal water-excitation double echo steady-state (DESS) with axial and coronal reformat images.ResultsEighty-five subjects (97.7%) were subjected to TKA, while only 2 subjects (2.3%) received UKA from the OAI database. Based on the preoperative MRI findings criteria, 51 of 87 subjects (58.6%) met the indication for TKA including the 2 UKA subjects above. This rate was significantly lower (p<0.001) than the actual TKA rate received. Among 85 subjects who actually underwent TKA, 31 subjects (36.5%) and 5 subjects (5.9%) met the indication for BKA and UKA, respectively.ConclusionsMany medial or lateral compartmental OA subjects, with or without patellar compartment defects have undergone TKA. The results of this study suggest the indication for partial arthroplasty, such as UKA or BKA, may increase when cartilage in each compartment, as well as ligaments and subchondral bone status are comprehensively evaluated.

Foraminoplastic transforaminal percutaneous endoscopic discectomy at the lumbosacral junction under local anesthesia in an elite rugby player

Percutaneous endoscopic discectomy (PED) is the least invasive disc surgery available at present. The procedure can be performed under local anesthesia and requires only an 8 mm skin incision. Furthermore, damage to the back muscle is considered minimal, which is particularly important for disc surgery in athletes. However, employing the transforaminal (TF) PED approach at the lumbosacral junction can be challenging due to anatomical constraints imposed by the iliac crest. In such cases, foraminoplasty is required in addition to the standard TF procedure. A 28-year-old man who was a very active rugby player visited us complaining of lower back and left leg pain. His visual analog scale (VAS) score for pain was 8/10 and 3/10, respectively. MRI revealed a herniated nucleus pulposus at L5-S level. TF-PED was planned; however, the anatomy of the iliac crest was later found to prevent access to the herniated mass. Foraminoplasty was therefore performed to enlarge the foramen, thereby allowing a cannula to be passed through the foramen into the canal without causing exiting nerve injury. The herniated mass was then successfully removed via the TF-PED procedure. Pain resolved after surgery, and his VAS score decreased to 0/10 for both back and leg pain. The patient returned to full rugby activity 8 weeks after surgery. In conclusion, even with an intracanalicular herniated mass at the lumbosacral junction, a TF-PED procedure is possible if additional foraminoplasty is adequately performed to enlarge the foramen.

MRI Changes of the Spinal Subdural Space after Lumbar Spine Surgeries: Report of Two Cases

Although magnetic resonance imaging (MRI) is frequently used to assess the lumbar spine, there are few reports in the medical literature that have evaluated using MRI immediately following spinal surgery. Furthermore, descriptions of the subdural changes after lumbar spine surgery are also infrequent. In this paper, we present two cases with subdural change seen on MRI immediately after lumbar surgery. Both the patients had mild symptoms that resolved spontaneously, and the follow-up MRI scans showed resolution of the subdural changes. Subdural changes should be considered as one of the possible causes of unexpected symptoms in patients following lumbar spinal surgery.

Diffusion tensor imaging and tractography of the sciatic nerve: assessment of fractional anisotropy and apparent diffusion coefficient values relative to the piriformis muscle, a preliminary study

ObjectivePiriformis muscle syndrome (PMS) is underdiagnosed. To evaluate the potential of diffusion tensor imaging and diffusion tensor tractography as innovative tools for the diagnosis of PMS by functional assessment of the sciatic nerve, the aims of this study are to assess the reproducibility and to evaluate the changes in the parameters at levels proximal and distal to the piriformis.Materials and methodsFractional anisotropy (FA) and the apparent diffusion coefficient (ADC) of the sciatic nerve at three levels were quantified twice each by two examiners using the fiber-tracking method. In the first part of the study, laterality and reproducibility were evaluated using intraclass correlation coefficients (ICC) in ten healthy volunteers. In the second part of the study, the healthy side and symptomatic side were assessed in ten consecutive patients with sciatica. There were three patients with no findings on lumbar magnetic resonance imaging (MRI).ResultsThere was no laterality in either FA or ADC values in asymptomatic patients at any level. The mean intra-rater ICC was 0.90 and the mean inter-rater ICC was 0.87. FA was significantly lower and ADC significantly higher on the symptomatic side at each level in patients with sciatica. In the three sciatica patients with no findings on lumbar MRI, FA was significantly lower and ADC was significantly higher only at levels distal to the piriformis. These patients experienced full pain relief after ultrasound-guided injection of local anesthesia.ConclusionsDiffusion tensor imaging and diffusion tensor tractography might be innovative tools for the diagnosis of PMS.

State-of-the-art ultrasonographic findings in lower extremity sports injuries

Athletes sometimes experience overuse injuries. To diagnose these injuries, ultrasonography is often more useful than plain radiography, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography can show both bone and soft tissue from various angles as needed, providing great detail in many cases. In conditions such as osteochondrosis or enthesopathies such as Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, bipartite patella, osteochondritis dissecans of the knee, painful accessory navicular,and jumpers knee, ultrasonography can reveal certain types of bony irregularities or neovascularization of the surrounding tissue. In patients of enthesopathy, ultrasonography can show the degenerative changes at the insertion of the tendon. Given its usefulness in treatment, ultrasonography is expected to become essential in the management of overuse injuries affecting the lower limb in athletes. J. Med. Invest. 62: 109-113, August, 2015.

Local administration of zoledronic acid for giant cell tumor of bone.

Giant cell tumor of bone is a locally aggressive tumor with a high local recurrence rate. Several adjuvant therapies have been employed to reduce the recurrence rate, but their effectiveness remains controversial. The authors attempted local administration of zoledronic acid, a nitrogen-containing bisphosphonate that strongly inhibits bone resorption, as an adjuvant treatment for histologically proven giant cell tumor of bone in 5 patients at their institution. After biopsy, 4 patients were treated with local administration of zoledronic acid with artificial bone and 1 was treated with zoledronic acid without artificial bone. Histologic response to the treatment was evaluated with surgically resected specimens. The 4 patients treated with artificial bone showed local control, with histologic tumor necrosis rates of 90%, 90%, 50%, and 10%. Magnetic resonance imaging showed poor gadolinium enhancement, and histologic examination after local zoledronic acid treatment showed tumor necrosis. One patient without artificial bone showed no histologic tumor necrosis and had local recurrence in soft tissue 18 months after tumor resection. A 3-week waiting period between biopsy and zoledronic acid treatment appears reasonable from the histological study. Complication of this therapy was delayed wound healing and it occurred in 2 cases. Taken together, this case series suggests that local administration of zoledronic acid with artificial bone is a potential adjuvant therapy for giant cell tumor of bone. On the other hand, effective local administration of zoledronic acid requires some bone matrix, including artificial bone. Campanaccis grading is important for predicting the effect of local administration of zoledronic acid.