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1.
Porto Biomed J ; 9(3): 256, 2024.
Article En | MEDLINE | ID: mdl-38903393

We developed two methods for three-dimensional (3D) evaluation of spinal alignment in standing position by image matching between biplanar x-ray images and 3D vertebral models. One used a Slot-Scanning 3D x-ray Imager (sterEOS) to obtain biplanar x-ray images, and the other used a conventional x-ray system and a rotating table. The 3D vertebral model was constructed from the CT scan data. The spatial position of the vertebral model was determined by minimizing the contour difference between the projected image of the model and the biplanar x-ray images. Verification experiments were conducted using a torso phantom. The relative positions of the upper vertebrae to the lowest vertebrae of the cervical, thoracic, and lumbar vertebrae were evaluated. The mean, standard deviation, and mean square error of the relative position were less than 1° and 1 mm in all cases for sterEOS. The maximum mean squared errors of the conventional x-ray system and the rotating table were 0.7° and 0.4 mm for the cervical spine, 1.0° and 1.2 mm for the thoracic spine, and 1.1° and 1.2 mm for the lumbar spine. Therefore, both methods could be useful for evaluating the spinal alignment in standing position.

3.
Dent Mater J ; 43(1): 44-51, 2024 Jan 30.
Article En | MEDLINE | ID: mdl-38044144

Using finite-element analysis, we aimed to determine the center of resistance (CRes) of the maxillary canine for setting orthodontic forces. The inclination of the canine was measured by first loading from the mesial to the distal side of the mesial root surface, then the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between two inclination lines. Twenty-one CRes values were calculated from a set of seven lines. These CRes data were then aggregated as a 95% confidence ellipsoid of width 0.170×0.016×0.009 mm with center points 4.269, 0.224, and 4.315 mm in the apical, mesial, and lingual directions from the origin, respectively. Further studies are required to effectively apply the CRes identified in this study to clinical applications.


Cuspid , Tooth Movement Techniques , Tooth Movement Techniques/methods , Tooth Root , Finite Element Analysis , Maxilla , Imaging, Three-Dimensional/methods
4.
Acta Trop ; 247: 107013, 2023 Nov.
Article En | MEDLINE | ID: mdl-37660777

In the endemic area of the liver fluke (Opisthorchis viverrini) infection, effective control of opisthorchiasis using One Health approaches requires transmission interruption in all hosts in the parasite life cycle. Owned domestic cats (Felis catus) are considered an important species among mammalian reservoirs. Similar to humans, household cats become infected by eating raw, contaminated fish and spread the O. viverrini eggs to the environment by defecation. In rural areas, cat owners usually feed their cats with human food or food waste, especially fish dishes. There is a high risk for cats to become infected and deposit eggs in the peri-household environment. The lack of research on domestic cats led us to study their roaming behavior, roaming range, habitat preference and risk of disease transmission. GPS loggers were harnessed to 28 domestic cats in 7 villages around Lawa Lake, the endemic area of human opisthorchiasis. All cats were examined for the O. viverrini infection status using modified formalin-ether concentration technique (MFECT) before application of the GPS device used to observe and record their roaming distance and range area. Then, composition analysis for habitat selection was performed using the location data. Additionally, cat owners were interviewed using participatory epidemiologic methods for their perceptions and knowledge about the reservoir hosts of this trematode. Our study suggested that the prevalence of O. viverrini in cats in this area has not declined appreciably in comparison with our previous study four years ago, although the treatment and control has been applied intensively in humans. The longest distance that individual cats roamed ranged from 51 to 363 meters (mean±SD = 154.48±90.71). The cats traveled tracks around their home. There was no significant difference in the average distance that cats ranged between O. viverrini infected group (154.13±72.80 meters) and the non-infected group (154.67±101.39 meters) was found. Compositional analysis suggested that the domestic cats preferred urban habitats where food and safety were probably more available. It appears that the main transmission route for infection of cats was contaminated fish fed to cats or fish that remained in their houses. Therefore, owners should refrain from feeding their cats potentially contaminated foods, food scraps and raw fish remains and prevent their cats from accessing them. Moreover, the participatory epidemiology results suggest that awareness of villagers is not enough for the effective and sustainable control of the disease.


Opisthorchiasis , Opisthorchis , Refuse Disposal , Humans , Cats , Animals , Opisthorchiasis/epidemiology , Opisthorchiasis/veterinary , Thailand/epidemiology , Eggs , Mammals
5.
Radiol Med ; 128(10): 1262-1270, 2023 Oct.
Article En | MEDLINE | ID: mdl-37658197

PURPOSE: Follow-up examinations after flow diverter (FD) treatment for cerebral aneurysms typically involve magnetic resonance imaging (MRI) or digital subtraction angiography (DSA). However, MRI is prone to vascular defects due to metal artifacts from FD, and DSA carries a risk of ischemic complications. In the context of computed tomography angiography (CTA), this study compares the efficacy of ultra-high-resolution CT (UHRCT) and novel reconstruction techniques, such as model-based iterative reconstruction (MBIR), against conventional methods such as filtered back projection (FBP) and hybrid iterative reconstruction (IR), to determine if they are a viable alternative to DSA in clinical settings. MATERIALS AND METHODS: A phantom study was conducted with the full-width half-maximum considered as the FD thickness. This study compared three reconstruction methods: MBIR, FBP, and hybrid IR. A clinical study was also conducted with 21 patients who underwent follow-up CTA after FD treatment. The FD's visibility was assessed using a 4-point scale in FBP, hybrid IR, and MBIR compared to cone-beam CT (CBCT) with angiographic systems. RESULTS: In the phantom study, FBP, hybrid IR, and MBIR visualized thinner FD thicknesses and improved detail rendering in that order. MBIR proved to be significantly superior in both the phantom and clinical study. CONCLUSION: UHRCT with MBIR is highly effective for follow-up evaluations after FD treatment and may become the first-choice modality in the future.


Computed Tomography Angiography , Intracranial Aneurysm , Humans , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/surgery , Follow-Up Studies , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Angiography, Digital Subtraction , Algorithms , Radiation Dosage
6.
Yonago Acta Med ; 66(3): 385-388, 2023 Aug.
Article En | MEDLINE | ID: mdl-37621982

Papillary glioneuronal tumor (PGNT) is a low-grade biphasic tumor that is composed of glial fibrillary acidic protein (GFAP)-positive glial cells and synaptophysin-positive neurons. We report a case of PGNT occurring in the right occipital lobe of a 48-year-old woman who presented with acute headache and left homonymous hemianopsia, the latter of which was difficult to distinguish from malignant brain tumors because of peritumoral brain edema, intratumoral hemorrhage, and intraoperative fluorescence staining. PGNT should be included as one of the differential diagnoses in cases where the tumor shows hemorrhagic change despite decreased perfusion in arterial spin labeling MRI.

7.
J Neuroendovasc Ther ; 17(2): 68-72, 2023.
Article En | MEDLINE | ID: mdl-37502128

Objective: Marfan's syndrome (MFS) is a systemic connective tissue disorder with autosomal dominant inheritance. Cardiovascular complications of MFS such as aortic root or valve disease and aortic aneurysm or dissection are potential cause of access route problems of mechanical thrombectomy (MT) for acute ischemic stroke (AIS). Here, we report a case of a patient with MFS who underwent MT for AIS. Case Presentation: A 58-year-old woman with MFS presented with a sudden onset of consciousness disturbance and right hemiparesis, and was referred to our hospital. After the infusion of tissue plasminogen activator, CTA showed a type III arch in the aortic arch and severe tortuosity of the thoracoabdominal aorta; thus, angiography was performed using the transbrachial approach. Left common carotid angiogram showed complete recanalization of the left middle cerebral artery. On the sixth day, the patient presented a sudden consciousness disturbance and left hemiparesis. MRA showed right internal carotid artery occlusion. MT was performed by the transbrachial approach, and complete recanalization was achieved on the first pass. Conclusion: MT via the transbrachial approach is a treatment option that should be considered, especially in MFS, where the transfemoral approach is difficult due to anatomical problems.

8.
J Neuroendovasc Ther ; 17(4): 97-100, 2023.
Article En | MEDLINE | ID: mdl-37502740

Objective: Complications of mechanical thrombectomy (MT) should be identified and managed because they often worsen clinical outcomes. Here we present a case of post-MT embolization of the artery supplying the oculomotor nerve, which has not previously been reported as a complication of MT. Case Presentation: An 81-year-old woman visited our hospital within 2 hours of the sudden onset of left hemiparesis and impaired awareness. MRA showed right middle cerebral artery (MCA) M1 segment occlusion and a possibly salvageable penumbra. We performed thrombectomy for right MCA occlusion with successful recanalization. In the final angiography view, the marginal tentorial artery was almost invisible. Ten hours after thrombectomy, the patient developed complete right oculomotor nerve palsy. Subsequent MRI showed ischemic lesions, but none in the oculomotor nucleus, and there were no lesions compressing the oculomotor nerve. We presume that embolization of the marginal tentorial artery caused oculomotor nerve palsy. The intracranial middle and distal portions of the oculomotor nerve are supplied by the superior branches of the inferolateral trunk and by the marginal tentorial artery. Conclusion: Occlusion of the marginal tentorial artery can cause oculomotor nerve palsy, although this has not previously been reported. Our case suggests that neurointerventional surgeons should evaluate patency of branches of the inferolateral trunk and the meningohypophyseal trunk during the procedure of MT.

9.
J Neurointerv Surg ; 2023 Jun 21.
Article En | MEDLINE | ID: mdl-37344176

BACKGROUND: Dual antiplatelet therapy (DAPT) is necessary to prevent thromboembolic complications after stent-assisted coiling (SAC) or flow-diversion (FD) for cerebral aneurysms, but the optimal antiplatelet regimen remains unclear. OBJECTIVE: To determine the optimal DAPT duration in patients with SAC/FD. METHODS: This multicenter cohort study enrolled patients who received SAC/FD for cerebral aneurysms at seven Japanese institutions between January 2010 and December 2020. The primary outcome was the time from procedure to the occurrence of a composite of target vessel-related thromboembolic events, procedure-unrelated major bleeding events, or death. The cumulative event-free survival rates were analyzed using a Kaplan-Meier curve, and the differences in each outcome between the groups dichotomized by the duration of DAPT were analyzed using the log-rank test. RESULTS: Of 632 patients (median observational period, 646 days), primary outcome occurred in 63 patients (10.0%), most frequently within 30 days after the procedure. The cumulative event-free survival rates at 30 days, 1 year, and 2 years after the procedure were 93.3% (91.4 to 95.3%), 91.5% (89.3 to 93.7%), and 89.5% (87.0 to 92.0%), respectively. The cumulative event-free survival rates after switching to monotherapy were similar for the >91 and <90 days DAPT groups in the population limited to patients who were switched from DAPT to monotherapy without major clinical events. CONCLUSIONS: Thromboembolic events rarely occurred beyond 30 days after SAC/FD. The duration of DAPT may be shortened if patients have a periprocedural period without events. Further prospective studies are warranted to determine the optimal duration of antiplatelet therapy. TRIAL REGISTRATION NUMBER: UMIN000044122 :https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000050384.

11.
Br J Neurosurg ; 37(3): 469-472, 2023 Jun.
Article En | MEDLINE | ID: mdl-31580167

Harvesting the superficial temporal artery (STA) is the first difficult step in extracranial-intracranial bypass surgery. There are various methods and instruments for harvesting the STA. We used the Lone Star (LS) retractor system for harvesting the STA. The LS retractor system is used in other surgical specialties. The LS retractor system consists of the retractor ring (14.1 cm × 14.1 cm) and elastic stays (5-mm sharp hook). The retractor ring can be used to adjust to the operative field. Retracting the loose connective tissue around the STA by the elastic stays can make harvesting the STA easy and safe. After harvesting the STA, retracting the skin and muscle by the elastic stays is useful for hemostasis during intracranial surgery and anastomosis. We used the LS retractor system in 26 consecutive patients to perform STA-MCA anastomosis between November 2015 and August 2018. All STAs were harvested without complications or injuries. The LS retractor system is a safe and useful method for harvesting the STA.


Cerebral Revascularization , Humans , Cerebral Revascularization/methods , Temporal Arteries/surgery , Microsurgery/methods , Anastomosis, Surgical , Middle Cerebral Artery/surgery
12.
Dent Mater J ; 42(1): 133-139, 2023 Jan 31.
Article En | MEDLINE | ID: mdl-36351599

We aimed to investigate the center of resistance (CRes) of the maxillary first molar to set the occlusal force through finite element analysis. The inclination of the molar was measured, with loading to the root on the crown, and the position and direction of the load that minimized the inclination were investigated. The CRes was defined as the set of midpoints of the minimum distances between the two lines. Nine hundred and ninety CRes points were estimated from forty-five lines. The CRes was estimated as the point 1.22 mm (Z), -0.74 mm (X), and 0.23 mm (Y) from the origin in the apical, distal, and buccal side directions, respectively, with an ellipsoid area of 1.578 (Z) mm×0.097 (X) mm×0.100 (Y) mm. Further research is required to make effective use of the CRes identified in this study for clinical applications.


Bite Force , Molar , Crowns , Finite Element Analysis , Imaging, Three-Dimensional/methods
13.
Biomed Mater Eng ; 34(2): 159-168, 2023.
Article En | MEDLINE | ID: mdl-36120759

BACKGROUND: Suprahyoid muscles behavior during the tongue lifting movement has not yet been elucidated. OBJECTIVE: The purpose of this study was to investigate the potential of elastography imaging to examine developmental oral dysfunction in children and oral hypofunction in older adults using sonography. METHODS: Tongue pressure was measured using a manometer with a probe. The tongue pressure was measured with simultaneously scanning the geniohyoid muscle (GHM) and the anterior belly of the digastric muscle (DGM) using sonographic elastography. Sagittal images of the GHM and coronal images of the DGM were used for the strain ratio measurement. The strain ratio of the muscles was measured three times for each subject with the tongue pressure values of 0-30 kPa. RESULTS: The strain ratio of the GHM were higher than those of the DGM at tongue pressure of 10, 20 and 30 kPa. The strain ratio of the GHM increased as the tongue pressure increased in all participants. In contrast, the strain ratio of the DGM tended to slowly decrease as tongue pressure increased in female participants. CONCLUSION: Sonographic elastography is useful for visual and quantitative evaluation of elastic properties in suprahyoid muscles during tongue lifting movements.


Elasticity Imaging Techniques , Tongue , Child , Humans , Female , Aged , Pilot Projects , Pressure , Deglutition/physiology , Neck Muscles/physiology , Elasticity
14.
Biomed Mater Eng ; 33(5): 337-349, 2022.
Article En | MEDLINE | ID: mdl-35253726

BACKGROUND: Knowledge of the biomechanics of the normal collateral ligaments is important to secure optimal stability of the knee following injury. Various in vitro methods have been described in evaluating the biomechanics of these ligaments. However, a method of direct evaluation has not been reported. OBJECTIVE: To determine the stiffness characteristics of the collateral ligaments of the knee using strain ultrasound elastography. METHODS: Strain ultrasound elastography was performed on different components of the collateral ligaments in various angles of knee flexion in 18 healthy males (36 ligaments). We measured relative stiffness of the ligaments using strain ratio (SR = target tissue strain/reference strain). A lower strain ratio indicates higher relative stiffness. RESULTS: There was moderate to excellent intra- and inter-rater agreement for strain ratio measurements in all ligament portions. Strain ratios were lowest at 0° in all three ligaments, indicating high relative stiffness. In the superficial and deep medial collateral ligaments, the strain ratio increased with increasing knee flexion, whereas in the lateral collateral ligament, stiffness showed a tendency to fluctuate. CONCLUSION: Strain ultrasound elastography is a reliable tool for monitoring relative stiffness of the collateral ligaments of the knee and is easily applied to the routine clinical setting.


Collateral Ligaments , Elasticity Imaging Techniques , Biomechanical Phenomena , Collateral Ligaments/diagnostic imaging , Humans , Knee Joint/diagnostic imaging , Male , Range of Motion, Articular
15.
J Neuroendovasc Ther ; 16(8): 413-418, 2022.
Article En | MEDLINE | ID: mdl-37502634

Objective: A case of cerebral venous sinus thrombosis (CVST) during pregnancy effectively recanalized by endovascular mechanical thrombectomy with the combined use of an aspiration catheter and a stent retriever is reported. Case Presentation: A 27-year-old woman at eight weeks' gestation developed sudden onset of right hemiparalysis and seizures and was referred to our hospital. Her National Institutes of Health Stroke Scale score on admission was 23. On MRI, diffusion-weighted imaging showed a hyperintensity area in the left frontal lobe, and T2* imaging showed hemorrhagic infarction in the same area. MR venography showed obstruction of the anterior two-thirds of the superior sagittal sinus (SSS). Anticoagulant therapy with heparin was started, but since the venous return was expected to be severely impaired, mechanical thrombectomy by endovascular surgery was selected, hoping to resolve symptoms early. Using a large-bore aspiration catheter in combination with a stent retriever, it was possible to safely guide the aspiration catheter into the anterior half of the SSS. The use of a large-bore aspiration catheter enabled retrieval of a large amount of thrombus in a short time, and complete recanalization was achieved. The patient's hemiplegia and aphasia improved significantly within a week after the procedure, and she was discharged without sequelae. Conclusion: Mechanical endovascular therapy of CVST performed with a combination of a large-bore aspiration catheter and a stent retriever should be considered particularly for patients with severe neurological symptoms or intracranial hemorrhage and for those who do not respond to anticoagulation therapy.

16.
J Orthop Sci ; 27(4): 751-759, 2022 Jul.
Article En | MEDLINE | ID: mdl-33966957

BACKGROUND: Proper identification of lumbosacral transitional vertebrae (LSTV) is important to characterize the relationship between the transitional segment and adjacent levels. Classical classification schemes are inaccurate with respect to the whole spine. We propose a precise vertebral numbering method and investigated the relationship between LSTV and whole-body sagittal alignment. METHODS: A total of 291 healthy adult volunteers with no history of spinal disease were evaluated with biplanar slot scanning full body stereoradiography to determine the prevalence of LSTV. Vertebrae were counted from the first cervical vertebra using both coronal and sagittal plane images. We then investigated the influence of LSTV on whole-body sagittal alignment in 279 participants. Whole-body key parameters descriptive statistics were compared among groups according to the number of vertebrae (L4, L5, and L6). Statistical analysis was performed between normal and LSTV cases using the Steel-Dwass analysis. RESULTS: Of the 291 subjects, 14 (4.8%) had 23 vertebrae and 16 (5.5%) had 25 vertebrae. Eleven (3.8%) had Th11, 3 (1.0%) had L4, and 1 (0.3%) had Th11 + L6, 16 (5.5%) had L6. Compared with the normal group, the sacral base in relation to the pelvis was higher in the L4 group and lower in the L6 group. The C2-C7 angle and lumbar lordosis (LL) were increased in both the L4 and L6 groups. All remaining parameters were decreased in the L4 group and increased in the L6 group. The relationship between LL and PI was similar in the normal and LSTV groups, despite the difference in the sacral base location. CONCLUSIONS: We propose a precise method for numbering the vertebrae using coronal and sagittal full body images. The spinopelvic parameters of the LSTV population significantly differed from those in the normal spine population due to differences in the sacral base location.


Lordosis , Lumbar Vertebrae , Adult , Healthy Volunteers , Humans , Lordosis/diagnostic imaging , Lumbar Vertebrae/diagnostic imaging , Lumbosacral Region/diagnostic imaging , Sacrum/diagnostic imaging
17.
Dent Mater J ; 41(1): 167-183, 2022 Feb 01.
Article En | MEDLINE | ID: mdl-34690228

Coronavirus disease pandemic has led to a shortage of disinfectant alcohol (DA; 76.9-81.4% ethanol solution) in Japan. This study investigated the availability of hypochlorous acid (HA) as an alternative disinfectant to DA in clinical environment. HA is a safe and economical disinfectant with a broad antibacterial spectrum and low risk of hand irritation, which is used worldwide. In this study, HA and sodium hypochlorite solution (SH) were degraded over time and the degradation was accelerated by temperature and lighting. Results of bactericidal effects of HA revealed that the realistic effective concentration should be 200 ppm. Compared with DA, the dental carbon steel burs were more severely rusted by SH and HA. These results indicated that high concentration of HA generated on-site could be an effective and safe disinfectant for use immediately after generation with consideration of object materials in clinical environment, as an alternative to DA.


Disinfectants , Disinfection , Anti-Bacterial Agents , Ethanol , Hypochlorous Acid , Sodium Hypochlorite/pharmacology , Steel
18.
Neuropathology ; 41(4): 315-323, 2021 Aug.
Article En | MEDLINE | ID: mdl-34258808

Intracranial myxoid mesenchymal tumor (IMMT) is a recently described, extremely rare group of neoplasms characterized by fusions between the female-expressed transcript (FET) family genes and the cAMP response element-binding protein (CREB) family genes. Controversy persists regarding whether the tumor is a myxoid variant of angiomatoid fibrous histiocytoma or a completely distinct clinicopathological entity. Here, we report a case of IMMT arising in the posterior fossa in a 65-year-old woman with a history of breast cancer. We performed total removal of the tumor, which histologically demonstrated features characteristic of IMMT but also bore a partial resemblance to conventional angiomatoid fibrous histiocytoma. Immunohistochemically, tumor cells were diffusely positive for desmin, vimentin, cluster of differentiation (CD) 99 (CD99), glucose transporter-1, and cytokeratin (CK) 8/18 (CK8/18), and focally positive for CK7, epithelial membrane antigen, mucin 4, anaplastic lymphoma kinase, calponin, and CD68. Molecular genetic analysis revealed a fusion between the Ewing sarcoma breakpoint region 1 (EWSR1) gene (EWSR1) and the cAMP-responsive element modulator (CREM) gene (CREM) called EWSR1:CREM fusion, which confirmed the diagnosis. The overlap of the pathological features of IMMTs and angiomatoid fibrous histiocytomas may support the recent theory that these tumors are two manifestations of a single entity. Moreover, our study indicated the broad spectrum of immunohistochemical phenotypes of these tumors, which should be noted during diagnosis. Further studies are needed to elucidate the histopathological concept, long-term prognosis, optimal treatment strategy, and factors associated with the prognosis and therapeutic options of this condition.


Brain Neoplasms , Histiocytoma, Malignant Fibrous , Adult , Aged , Biomarkers, Tumor/genetics , Brain Neoplasms/genetics , Cyclic AMP Response Element Modulator/genetics , Cyclic AMP Response Element-Binding Protein , Female , Gene Fusion , Humans , RNA-Binding Protein EWS/genetics
19.
Yonago Acta Med ; 64(2): 155-161, 2021 May.
Article En | MEDLINE | ID: mdl-34025189

Magnetic resonance imaging (MRI) is the preferred imaging technique for the sellar and parasellar regions. In this review article, we report our clinical experience with MRI for hypothalamic and pituitary lesions, such as pituitary adenomas, craniopharyngiomas, Rathke cleft cysts, germinoma, and hypophysitis with reference to the histopathological findings through a review of the literature. Our previous study indicated that three dimensional-spoiled gradient echo sequence is a more suitable sequence for evaluating sellar lesions on postcontrast T1 weighted image (WI). This image demonstrates the defined relationship between the tumor and its surroundings, such as the normal pituitary gland, cavernous sinus, and optic pathway. We demonstrated the characteristic MRI findings of functioning pituitary adenoma. In growth hormone-producing adenoma, signal intensity on T2WI is important to differentiate densely from sparsely granulated somatotroph adenomas. In prolactin-producing pituitary adenomas, distinct hypointense areas in early phase on T2WI, possibly owning to diffuse hemorrhage, indicate pronounced regressions of invasive macroprolactinomas during cabergoline therapy. The two histopathological subtypes, adamantinomatous and squamous papillary craniopharyngioma, differ in genesis. Calcified tumors are mostly adamantinomatous type. On MRI, these lesions have a heterogenous appearance with a solid portion and cystic components. The solid portions and cyst wall enhance heterogeneously. Although cyst fluid of Rathke cleft cysts show variable intensities on MRI, intracystic waxy nodule can be hypointense on T2WI. The enhancing cyst wall may contain the squamous metaplasia. Cystic lesions of the sellar and parasellar areas may be difficult to differentiate on a clinical, imaging, or even histopathological basis.

20.
Biomed Mater Eng ; 32(5): 257-266, 2021.
Article En | MEDLINE | ID: mdl-33998528

BACKGROUND: The patellar and quadriceps tendons are responsible for the extension mechanism of the knee joint and frequently become inflamed during sports. Diagnosis and determination of when an athlete can return to sports following these injuries are usually performed by assessing morphological features and functional outcomes. Nevertheless, mechanical properties are not being assessed. OBJECTIVE: To describe the stiffness characteristics of these two tendons over the range of knee flexion and to test the feasibility of using strain ultrasound elastography (SE). METHODS: SE with an acoustic coupler as the reference was performed for nine healthy males. Relative stiffness measurements were obtained using the strain ratio (SR = target tissue strain/reference strain) by placing the knee in five different flexion angles. Lower SR indicates higher relative stiffness. RESULTS: This study showed reliable measurement with good intra- and inter-rater agreement for SR at 30°. SR of the quadriceps tendon decreases as knee flexion increases, indicating increased relative stiffness. In the patellar tendon, no significant difference was observed between 30° and 60°. Beyond 60°, relative stiffness increased constantly. CONCLUSIONS: SE is a reproducible and feasible tool to monitor relative stiffness of the patellar and quadriceps tendons in routine clinical settings.


Elasticity Imaging Techniques , Patellar Ligament , Humans , Male , Patellar Ligament/diagnostic imaging , Quadriceps Muscle/diagnostic imaging , Range of Motion, Articular , Tendons/diagnostic imaging
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