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Δευτέρα, 16 Απριλίου 2018

Isolated subcutaneous nontuberculous mycobacterial infection: a rare case initially mischaracterized as a soft tissue malignancy

Abstract

The occurrence of nontuberculous mycobacterial (NTM) infection is rare, and the involvement of the musculoskeletal system is even less common. However, the incidence of soft tissue and skin NTM infection is increasing, particularly in patients who undergo injections and minor surgical procedures. Given the non-specific clinical manifestations of NTM infection, the lack of knowledge among physicians regarding this rare infection could lead to inaccurate and delayed diagnosis. Herein, we present a case of an isolated subcutaneous NTM infection caused by Mycobacterium abscessus in the upper back of an immunocompetent 68-year-old woman. The clinical presentation, magnetic resonance imaging findings (including diffusion-weighted imaging), and pathologic findings of subcutaneous NTM infection are described and compared with those of tuberculosis and tumor presentations to provide a more accurate clinical picture for a differential diagnosis.



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Avulsion fracture of an ossified pes anserinus tendon post-lateral patellar dislocation

Abstract

The pes anserinus is a common tendon comprising the tendinous insertions of the sartorius, gracilis, and semitendinosus muscles. It inserts at the anteromedial aspect of the tibia and plays a significant role in stabilization of the medial side of the knee joint. The current article presents a case with recurrent lateral patellar dislocations causing chronic stress along the medial knee stabilizers and consecutive enthesophyte formation at the insertion of the pes anserinus tendon that showed a transverse fracture upon a subsequent incident of traumatic lateral patellar dislocation. Avulsion injuries of the pes anserinus tendon are rarely encountered, and to our knowledge, association with recurrent lateral patellar dislocations has not been described before.



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2017 Award Winning Papers



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MRI in chronic groin pain: sequence diagnostic reliability compared to systematic surgical assessment

Abstract

Objective

To determine the diagnostic reliability of magnetic resonance imaging (MRI) sequences in chronic groin pain (CGP) compared to surgery and try to propose a suitable MRI protocol.

Materials and methods

Forty-three consecutive patients with resistant clinical CGP underwent a pre-surgical pelvis MRI. Eight MRI sequences were acquired: axial fast spin-echo T1-weighted (FSE T1), coronal FSE T1, axial-oblique (in symphysis plane) proton density weighted with fat saturation (PDFS), coronal PDFS, sagittal PDFS, axial FSE T1 with fat saturation and gadolinium enhancement (FSGE), coronal FSE T1 FSGE and axial FSE T1 with Valsalva maneuver (VM). These sequences were reviewed for pubic symphysis assessment, adductor longus (AL) tendon and abdominal wall (AW) injuries. The same surgeon operated on all of these patients (26 AL and 49 AW). Sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative prospective value (NPV) and accuracy of each sequence and combinations for AL or AW injuries were calculated in comparison to surgical findings.

Results

One hundred ninety-two sequences were obtained. Coronal T1 FSGE and axial T1 VM proved to be the most reliable sequences (accuracy: 91.67% in AL and 83.33% in AW). The best sequence combination was coronal T1, axial PDFS, sagittal PDFS and axial T1 VM (accuracy: 77.78%; Se: 100.00%, Sp: 69.23%, PPV: 55.56%, NPV: 100.00%).

Conclusion

MRI has 77.78% accuracy, 100.00% sensitivity, 69.23% specificity, 55.56% PPV and 100.00% NPV in evaluating CGP, with coronal T1-axial PDFS-sagittal PDFS-axial T1 VM as the optimal protocol in terms of diagnostic performance within a reasonable scan time. Diagnostic performance of MRI was examined in the evaluation of CGP using surgery as reference standard.



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Response to: Periosteal mesenchymal chondrosarcoma of the tibia



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An intra-articular synovial lipoma of the hip, possibly causing osteoarthritis: a case report and review of the literature

Abstract

In this report, we present the case of an intra-articular synovial lipoma in a 58-year-old female with a coincident marked unilateral hip osteoarthritis. This patient suffered from right hip pain that developed gradually over 2 years. Physical examination noted decreased range of motion and evidence of impingement. MR and CT images showed an intra-articular fat-intense mass in the hip joint that was excised and confirmed as a synovial lipoma on histology. This case reveals that an intra-articular lipoma of the hip could be accompanied by pain or impingement and followed by hip osteoarthritis even in the absence of trauma.



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MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a ‘positive MRI’

Abstract

Objective

To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME).

Materials and methods

A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16–45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated.

Results

BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis.

Conclusion

Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is 'positive' or 'not positive' for sacroiliitis associated with spondyloarthritis.



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Test yourself: weakness and wasting of forearm



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Periosteal mesenchymal chondrosarcoma of the tibia



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Hallux saltans due to stenosing tenosynovitis of flexor hallucis longus: dynamic sonography and arthroscopic findings

Abstract

Triggering of the toes is rare, with isolated cases reported in the literature involving predominantly the flexor hallucis longus (FHL) tendon, a condition known as "hallux saltans" (HS). We report the dynamic sonographic findings of a 42-year-old female with a 2-month history of ankle pain and triggering of right hallux, consistent with HS. Sonography demonstrated tenosynovitis and focal thickening of FHL at the level of hindfoot, with a fibrous band adjacent to the tendon. Dynamic ultrasound showed triggering and snapping of FHL tendon during hallux flexion and extension, respectively. We present comprehensive documentation of this rare entity, including sonographic still images and cine clips, as well as correlation with arthroscopic surgical findings.



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Atypical lipomatous tumor of the hand with transformation to dedifferentiated liposarcoma: a case report

Abstract

Atypical lipomatous tumor/well-differentiated liposarcoma is the most common sarcoma of soft tissue in adults. We describe the clinical, radiologic, and pathologic features of an atypical lipomatous tumor arising within the soft tissue of the left hand of a 68-year-old female that underwent transformation to dedifferentiated liposarcoma and eventually metastasized. At initial presentation, imaging demonstrated an extensively calcified fatty soft tissue mass with displacement of the digits. Following biopsy and staged debulking, the patient subsequently developed local recurrence, dedifferentiation, and widespread metastases to the lungs, pancreas, bone, and soft tissues. To our knowledge, this is the first case of a cytogenetically proven atypical lipomatous tumor of the hand that has undergone dedifferentiation with widespread metastases.



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Isolated avulsion fracture of the first metatarsal base at the peroneus longus tendon attachment: a case report

Abstract

Avulsion fractures of the first metatarsal (MT1) base at the peroneus longus (PL) tendon attachment are rare and may be undiagnosed during an emergency visit. If the injury is not treated properly, chronic pain or persistent impairment for inversion and plantar-flexion of the first ray may occur. This case report presents a 30-year-old woman who presented 10 weeks post trauma to a foot and ankle surgeon due to a swollen right midfoot with diffuse tenderness over the medial Lisfranc joint. Further evaluation showed an isolated avulsion fracture of the first metatarsal, which was undiagnosed during the emergent visit following the accident. In this case, the patient was successfully treated conservatively. The goal of this article is to raise awareness of this rare injury for radiologists and orthopedic surgeons.



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Arthroscopic primary repair of the anterior cruciate ligament: what the radiologist needs to know

Abstract

Recently, there has been a renewed interest in primary repair of proximal anterior cruciate ligament (ACL) tears. Magnetic resonance imaging (MRI) plays an important role in preoperative patient selection and in postoperative ligament assessment. Knowledge of the imaging factors that make patients candidates for primary ACL repair, namely proximal tear location and good tissue quality, can help radiologists provide information that is meaningful for surgical decision making. Furthermore, an understanding of the surgical techniques can prevent misinterpretation of the postoperative MRI. This article reviews preoperative MRI characterization of ACL injuries, techniques of arthroscopic primary ACL repair surgery and examples of postoperative MRI findings.



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Test yourself: weakness and wasting of forearm



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CT-guided percutaneous biopsy of sclerotic bone lesions: diagnostic outcomes

Abstract

Objective

To determine the diagnostic yield of CT-guided percutaneous biopsy of densely sclerotic bone lesions.

Materials and methods

We retrospectively analyzed CT-guided percutaneous bone biopsies performed at our institution from September 2008 through August 2011 (329 cases) and from September 2012 through August 2015 (324 cases) after adoption of a battery-powered drill system (OnControl). Bone lesions were included in the analysis if they were >70% sclerotic by visual inspection, had a density > 2 times that of adjacent trabecular bone, and had an attenuation of ≥250 HU. Pathological fractures, diskitis–osteomyelitis, and osteoid osteomas were excluded. Eligible cases were characterized by lesion location, maximum lesion diameter, mean density, biopsy needle type and gauge, reported complications, and histological diagnosis. Clinical and imaging follow-up was used to confirm histological diagnosis. Cases in which a benign histological diagnosis could not be confirmed by imaging over a minimum period of 1 year were excluded.

Results

A total of 37 biopsies of sclerotic bone lesions met the inclusion criteria, 17 of which were performed with a power drill needle and 20 of which were performed with a manually driven needle. The mean lesion density was 604.1 HU. The overall diagnostic yield was 78.4%; overall diagnostic accuracy was 94.6%, and the false-negative rate was 5.4%. Diagnostic yield and accuracy were 82.4% and 100% respectively, with a power drill and 75% and 90% respectively, with a manual device. Diagnostic yield for lesions ≥700 HU was 90% (9 out of 10).

Conclusion

Densely sclerotic bone lesions are amenable to percutaneous needle biopsy.



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Unusual circumstances to diagnose cervical Pott’s disease

Abstract

Tuberculous spondylodiscitis usually affects the dorso-lumbar spine, and its cervical location is a rare condition that can mimic other diseases and consequently cause treatment delays. We report a case of tuberculous spondylodiscitis of the lower cervical spine discovered under unusual circumstances in a patient with severe polytrauma involving a cranio-cerebral trauma, a non-displaced fracture of the two laminæ and the spinous process of the C6 vertebrae as well as fibular and tibial shaft fractures. The patient underwent static tibial nailing, and a collar with occipital and chin supports was applied. At 2-month follow-up, the patient presented with severe neck pain without neurologic deficits. Plain and dynamic cervical radiographs showed a stable C6-C7 subluxation and C7 superior endplate collapse. The CT scan also outlined prevertebral soft tissue swelling. The MRI showed a C6–C7 spondylodiscitis associated with a prevertebral abscess with am 8-cm major axis. The diagnosis of C6–C7 Pott's disease was confirmed by a CT-guided biopsy. The patient received 12 months of antituberculous chemotherapy, after which the paravertebral abscess completely disappeared, and the patient has had no functional sequelae. The diagnosis of cervical spine tuberculosis is difficult and requires a high level of attention. Delays in establishing the diagnosis and starting the appropriate treatment result in severe complications such as spinal cord compression and spinal deformity, which are difficult to manage.



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Osteogenic melanoma: report of a case mimicking osteosarcoma and review of the literature

Abstract

A 32-year-old male presented with a right thumb lesion of 11-month duration. A clinical diagnosis of pyogenic granuloma was entertained but the lesion failed to respond to conservative therapy and eventually necessitated amputation of his thumb. MRI of the right thumb showed an ill-defined, heterogeneously enhancing, infiltrating mass within the dorsal soft tissues abutting the distal phalanx and measuring 4.2 × 2.4 × 0.7 cm. Histologically, the tumor was composed of a high-grade osteosarcoma with a chondrosarcomatous component localized within the underlying bone and a more superficial spindle cell component in the overlying soft tissue. The epidermis was focally ulcerated overlying the lesion. The key to the diagnosis was provided by intense staining of the spindle cell component for S100 protein indicative of a spindle cell melanoma. The presence of an associated osteogenic sarcomatous component established a final diagnosis of osteogenic melanoma. The localization of this element to phalangeal bone is distinctly unusual and resulted in the close resemblance to a primary osteogenic sarcoma.



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Intraarticular calcifying aponeurotic fibroma of the wrist: mimicking gout or calcium pyrophosphate dihydrate deposition disease

Abstract

Calcifying aponeurotic fibroma is a rare, benign fibroblastic tumor that typically occurs in the palms of the hands and soles of the feet in children and adolescents. We report an unusual case of a calcifying aponeurotic fibroma with diffuse intra-articular involvement of the carpal joints in a 59-year-old female. Radiographs and computed tomography scans revealed a large lobulated soft tissue mass with multiple stippled calcifications around the carpal joints and numerous erosions of the second to fifth carpometacarpal and intercarpal joints. Magnetic resonance imaging showed diffuse multinodular synovial proliferation with inhomogeneous hypo- to isointense signal intensity on T1-weighted images, inhomogeneous hypointense to hyperintense signal intensity on T2-weighted images, and inhomogeneous intense enhancement on fat-suppressed contrast-enhanced T1-weighted images. Radiologic diagnosis included gout, calcium pyrophosphate dihydrate deposition disease, and tenosynovial giant cell tumor. Surgical excision was performed, and the mass was diagnosed on pathologic examination as a calcifying aponeurotic fibroma. There has been no reported case of a calcifying aponeurotic fibroma with diffuse intra-articular involvement of the carpal joints in the literature.



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Pulse-dose radiofrequency treatment in pain management—initial experience

Abstract

Radiofrequency procedures have been used for treating various chronic pain conditions for decades. These minimally invasive percutaneous treatments employ an alternating electrical current with oscillating radiofrequency wavelengths to eliminate or alter pain signals from the targeted site. The aim of the continuous radiofrequency procedure is to increase the temperature sufficiently to create an irreversible thermal lesion on nerve fibres and thus permanently interrupt pain signals. The pulsed radiofrequency procedure utilises short pulses of radiofrequency current with intervals of longer pauses to avert a temperature increase to the level of permanent tissue damage. The goal of these pulses is to alter the processing of pain signals, but to avoid relevant structural damage to nerve fibres, as seen in the continuous radiofrequency procedure. The pulse-dose radiofrequency procedure is a technical improvement of the pulsed radiofrequency technique in which the delivery mode of the current is adapted. During the pulse-dose radiofrequency procedure thermal damage is avoided. In addition, the amplitude and width of the consecutive pulses are kept the same. The method ensures that each delivered pulse keeps the same characteristics and therefore the dose is similar between patients. The current review outlines the pulse-dose radiofrequency procedure and presents our institution's chronic pain management studies.



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Association between pain severity and clinico-histopathological findings in the mandibular canal and inferior alveolar nerve of patients with advanced mandibular osteoradionecrosis

Pain is one of the most problematic symptoms in patients with osteoradionecrosis (ORN) of the jaws. This study investigated the associations between pain severity and morphological alterations of the mandibular canal (MC) and inferior alveolar nerve (IAN), in respective computerized tomography (CT) images and resected specimens of mandibular ORN.

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3D dental and craniofacial manifestations in patients with late diagnosis of mucopolysaccharidosis type II: report of 2 cases

The objective of this study was to report the clinical evaluation results and 3D dental and craniofacial characteristics observed in two male patients with mucopolysaccharidosis type II (MPS-II). The patients were evaluated clinically (soft tissue evaluation, occlusion, periodontal and dental examination) and by craniofacial computed tomography (CT), with evaluation of 3D images in ITK-Snap and 3D Slicer® software. Mandibular 3D volumetric label maps were built from CT scans of both patients and compared through superimposition to a healthy patient's mandibular images.

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Does the orthognathic surgery improve myofacial pain in individuals with skeletal class III? one year follow-up

Objective: The objective of the present study was to evaluate the effect of orthognathic surgery on temporomandibular disorder (TMD) in patients with skeletal class III malocclusion. Study design: Forty-seven patients undergoing surgery were evaluated using Axis I of the Research Diagnostic Criteria/TMD index by a trained examiner, consecutively, at three different periods: 1 week before operation (T0), 6 months after operation (T1), and 1 year after operation (T2). Bivariate analyses were performed to compare the evaluation periods (p<0.05).

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Imaging appearance of well-differentiated liposarcomas with myxoid stroma

Abstract

Objective

Describe the imaging appearance of well-differentiated liposarcoma with myxoid stroma (WDLMS) and correlate with histopathology.

Materials and methods

A keyword search of the institution medical records was performed from 1 January 2000 to 30 June 2017. The histopathology slides of cases identified in this fashion were then reviewed by a pathologist. Additional cases were prospectively collected from extramural referrals and tumor boards. Diagnostic imaging studies of pathologically proven cases of WDLMS were then reviewed in consensus and correlated with pathology.

Results

Ten cases of pathologically proven WDLMS were identified (7 men, 3 women, ages 26–81). Tumor location included the retroperitoneum (n = 5), thigh (n = 4), and the shin (n = 1). Nine patients had macroscopic fat on imaging. The nonlipomatous components had a variable appearance, including septal, nodular, and lacelike patterns. Two cases included two distinct areas that were predominantly myxoid or lipomatous ("bi-morphic"). One tumor had no macroscopic fat on imaging. On CT, the nonlipomatous nodular components were hypodense/had hypodense areas. On MRI, the nodular components had intermediate/bright T2W signal. Interval nonlipomatous nodular growth was identified in 3 cases.

Conclusion

WDLMS may present on imaging as a mass with variable morphology and amounts of nonlipomatous components. Histopathological diagnosis of WDLMS is challenging and imaging correlation may be helpful, as this tumor may have ≥50% fatty volume, may have a myxoid nodular component or bi-morphic appearance, or may be located in the retroperitoneum, features that are unusual for myxoid liposarcoma. WDLMS with a nodular component cannot be distinguished from dedifferentiated liposarcoma based on imaging alone.



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CT-guided biopsy in suspected spondylodiscitis: microbiological yield, impact on antimicrobial treatment, and relationship with outcome

Abstract

Purpose

To investigate the clinical impact of CT-guided biopsy, as performed in routine clinical practice, in patients with suspected spondylodiscitis on MRI in terms of culture yield, impact on antimicrobial treatment, and outcome.

Methods

This study included 64 patients with MRI findings compatible with spondylodiscitis who underwent CT-guided biopsy.

Results

Initial CT-guided biopsies were culture-positive in 20/64 (31.3%, 95% confidence interval [CI] 21.2–43.3%). Repeat CT-guided biopsies (after initial negative biopsy) were culture-positive in an additional 5/15 (33.3%, 95% CI 15.2–58.3%). Serum leukocytes, C-reactive protein, pre-biopsy use of antibiotics, neurological symptoms, MRI findings, vertebral height loss, and hyperkyphosis were not significantly different between culture-positive and culture-negative cases (P = 0.214–1.000); 75% (15/20) of initial CT-guided biopsies that were culture-positive provided additional information to clinicians for guiding antibiotic treatment. Sixty-two of 64 patients (96.9%, 95% CI 89.3–99.1%) would have been adequately treated if a strategy was followed that would subject all patients without clinical findings suspicious for "atypical" microorganisms and negative blood cultures to empirical antibiotics (i.e., clindamycin for coverage of Gram-positive bacteria) without using biopsy results to determine the optimal antibiotic regimen. Outcome within 6 months (development of neurologic or orthopedic complications, surgery, and death) was not significantly different (P = 0.751) between culture-positive and culture-negative patients.

Conclusions

Although CT-guided biopsies are culture-positive in a minority of cases, the majority of positive cultures are useful to tailor antibiotic treatment. Empirical treatment with clindamycin may cover almost all micro-organisms in positive biopsy specimens, provided patients are not immunocompromised. Outcome appears similar between culture-positive and culture-negative patients.



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Magnetic resonance imaging during management of patients with transfusion-dependent thalassemia: a single-center experience

Abstract

Background

Cardiac and hepatic magnetic resonance imaging evaluation during treatment can tailor physicians' chelation therapy titrations.

Aim

The aim of the study was to assess the relationship of cardiac and hepatic T2* values with chelation therapy in patients with transfusion-dependent thalassemia (TDT).

Methods

A total of 106 patients with TDT who were followed up in Istanbul Medical Faculty Thalassemia Center were evaluated for the study. Forty-eight (45%) patients with TDT had more than one consecutive MRI examination. The patients were divided into three subgroups according to the cardiac T2* values as the high-risk group (T2* MRI < 10 ms), medium-risk group (T2* MRI 10-20 ms), and the low-risk group (T2* MRI > 20 ms).

Results

The majority of patients used DFX (deferasirox) (79%) and deferiprone (DFP) (17%). Approximately 80% of patients according to cardiac T2* value and 40% of patients according to hepatic T2* value were initially in the low-risk group. Patients with follow-up MRI examinations exhibited significant improvement in liver iron concentration, which correlated with an increase in hepatic T2* values. The decrease of liver iron concentration was prominent in the DFX group (p < 0.01). The serum ferritin level was significantly correlated with liver iron concentrations (rs = 0.65, p < 0.001), hepatic T2* value (rs = − 0.62, p < 0.001), but not with cardiac T2* value (rs = − 0.20, p = 0.07).

Conclusion

Cardiovascular and hepatic MRI is a useful follow-up tool during the assessment of risk groups and chelation therapy of patients with TDT. Consecutive MRI tests showed good monitoring of cardiac and liver iron overload.



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Determination of optimal ultrasound planes for the initialisation of image registration during endoscopic ultrasound-guided procedures

Abstract

Purpose

Navigation of endoscopic ultrasound (EUS)-guided procedures of the upper gastrointestinal (GI) system can be technically challenging due to the small fields-of-view of ultrasound and optical devices, as well as the anatomical variability and limited number of orienting landmarks during navigation. Co-registration of an EUS device and a pre-procedure 3D image can enhance the ability to navigate. However, the fidelity of this contextual information depends on the accuracy of registration. The purpose of this study was to develop and test the feasibility of a simulation-based planning method for pre-selecting patient-specific EUS-visible anatomical landmark locations to maximise the accuracy and robustness of a feature-based multimodality registration method.

Methods

A registration approach was adopted in which landmarks are registered to anatomical structures segmented from the pre-procedure volume. The predicted target registration errors (TREs) of EUS-CT registration were estimated using simulated visible anatomical landmarks and a Monte Carlo simulation of landmark localisation error. The optimal planes were selected based on the 90th percentile of TREs, which provide a robust and more accurate EUS-CT registration initialisation. The method was evaluated by comparing the accuracy and robustness of registrations initialised using optimised planes versus non-optimised planes using manually segmented CT images and simulated ( \(n=9\) ) or retrospective clinical ( \(n=1\) ) EUS landmarks.

Results

The results show a lower 90th percentile TRE when registration is initialised using the optimised planes compared with a non-optimised initialisation approach (p value \(< 0.01\) ).

Conclusions

The proposed simulation-based method to find optimised EUS planes and landmarks for EUS-guided procedures may have the potential to improve registration accuracy. Further work will investigate applying the technique in a clinical setting.



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Mandibular canal branching assessed with cone beam computed tomography

Abstract

Purpose

The mandibular canal must be considered in dental procedures to avoid injuries of the alveolar inferior nerve. The occurrence of anatomical variations of the mandibular canal increases the risk of neurovascular injuries. The purpose of this study was to identify and describe the prevalence of mandibular canal branching (MCB) using cone beam computer tomography (CBCT).

Methods

Seven hundred standardized CBCTs were selected. The images were evaluated for the presence of MCB and for the detection of pathologies that could affect the structure of the canals. The data were analyzed using descriptive statistics and the Chi-squared test.

Results

The prevalence of MCB was 41.1%. There was no statistical difference between genders with the presence of the branches (p > 0.005). The highest prevalence was in the premolar and retromolar regions. Pathologies found in the molar region were frequently connected with MCB (77.8%), and the most common pathology related to branches was periapical lesion.

Conclusions

Mandibular canal branching presented a high prevalence in CBCT imagery, more frequently located in regions of the premolar and retromolar. An adequate diagnosis of the MCB is necessary to perform dental procedures and verify possible associated pathologies.



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MRI patient selection for endovascular thrombectomy in acute ischemic stroke: correlation between pretreatment diffusion weighted imaging and outcome scores

Abstract

Introduction

Eligibility for endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) depends, amongst other factors, on CT- or MR-based scores. The aim of this study was to investigate the role of Alberta Stroke Program Early CT score based on diffusion weighted imaging (MR-ASPECT) in the assessment of brain damage pre-EVT, patient selection for EVT and outcome.

Materials and methods

We included in this study patients with National Institute of Health stroke score (NIHSS) at admission ≥ 8, MR-ASPECT ≥ 5 and anterior AIS, who were treated with EVT in our hospital. All patients were clinically evaluated at admission, post-EVT, discharge and at 3-month follow-up. We used MR-ASPECT to establish infarct core extension at admission. We evaluated ASPECT score at admission (CT-ASPECT-IN), 24 h after EVT and at discharge, NIHSS, modified Ranking Scale (mRS), Thrombolysis in Cerebral Infarction scale (TICI), onset-to-intervention-delay (OTID) and Collateral Circulation Score (CCS).

Results

68 patients (mean age 78 ± 11.9 years) were included in this study. 54.4 and 64.7% of patients had strong clinical improvement after 24 h from EVT and at discharge, respectively. NIHSS evaluated 24 h after EVT correlated with CCS, TICI and OTID. We observed a favourable outcome (mRS 0–2) in 52.9% of patients at 3-month follow-up. MR-ASPECT score correlated with post-EVT outcome better than CT-ASPECT-IN scores.

Conclusion

MR-ASPECT score based on diffusion weighted imaging is useful for the selection of patients with AIS that can have a favourable outcome from EVT. A prompt EVT has huge impact on patient outcome.



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Septo-optic Dysplasia

Abstract

Purpose

Septo-optic dysplasia is a congenital disorder consisting of optic nerve hypoplasia and absent septum pellucidum. While associated anomalies have been described, olfactory sulcus and bulb-tract hypoplasia have been scantily reported and was the focus of this study.

Methods

The picture archival and communications system and radiology information system (PACS-RIS) was searched over 15 years for patients with suspected septo-optic dysplasia (n= 41) and cerebral magnetic resonance imaging (MRI). Included patients had coronal (≤3 mm), axial (≤4 mm), and sagittal (≤4 mm) imaging reviewed by two staff neuroradiologists by consensus. Both olfactory sulcus and bulb-tract hypoplasia were ascribed a grade of 0 (normal) to 3 (complete hypoplasia). Other associated congenital anomalies were recorded, if present. Incidence of anomalies were compared to age-matched and gender-matched control patients.

Results

Out of 41 septo-optic dysplasia patients 33 were included (mean age = 120.7 months), with 8 excluded due to isolated septum pellucidum absence (n= 5), isolated bilateral optic hypoplasia (n= 2), or inadequate imaging (n= 1). An olfactory sulcus was hypoplastic on one or both sides in 14/33 (42.4%). Olfactory bulb hypoplasia was noted in one or both tracts in 15/33 (45.4%). A significant correlation was found between degree of olfactory sulcal and bulb-tract hypoplasia (ρ = 0.528, p= 0.0009). Other anomalies were: anterior falx dysplasia (n= 16, 48.5%), incomplete hippocampal inversion (n= 14, 42.4%), polymicrogyria (n= 11, 33.3%), callosal complete or partial agenesis (n = 10, 30.3%), schizencephaly (n = 8, 24.2%), ectopic posterior pituitary (n= 6, 18.2%), and nodular heterotopia (n= 4, 12.1%). Of the age-matched control patients 10/33 (30.3%) had at least mild anterior falx hypoplasia, and 1 control patient was noted to have unilateral incomplete hippocampal inversion (IHI); none of the age-matched control patients had olfactory sulcus or bulb-tract hypoplasia.

Conclusion

Olfactory sulcus and bulb-tract hypoplasia are fairly common in septo-optic dysplasia and can be discordant between sides. Of the other associated anomalies, anterior falx dysplasia seems to be the most common.



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In vivo estimation of target registration errors during augmented reality laparoscopic surgery

Abstract

Purpose

Successful use of augmented reality for laparoscopic surgery requires that the surgeon has a thorough understanding of the likely accuracy of any overlay. Whilst the accuracy of such systems can be estimated in the laboratory, it is difficult to extend such methods to the in vivo clinical setting. Herein we describe a novel method that enables the surgeon to estimate in vivo errors during use. We show that the method enables quantitative evaluation of in vivo data gathered with the SmartLiver image guidance system.

Methods

The SmartLiver system utilises an intuitive display to enable the surgeon to compare the positions of landmarks visible in both a projected model and in the live video stream. From this the surgeon can estimate the system accuracy when using the system to locate subsurface targets not visible in the live video. Visible landmarks may be either point or line features. We test the validity of the algorithm using an anatomically representative liver phantom, applying simulated perturbations to achieve clinically realistic overlay errors. We then apply the algorithm to in vivo data.

Results

The phantom results show that using projected errors of surface features provides a reliable predictor of subsurface target registration error for a representative human liver shape. Applying the algorithm to in vivo data gathered with the SmartLiver image-guided surgery system shows that the system is capable of accuracies around 12 mm; however, achieving this reliably remains a significant challenge.

Conclusion

We present an in vivo quantitative evaluation of the SmartLiver image-guided surgery system, together with a validation of the evaluation algorithm. This is the first quantitative in vivo analysis of an augmented reality system for laparoscopic surgery.



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Fiducial-based fusion of 3D dental models with magnetic resonance imaging

Abstract

Purpose

Magnetic resonance imaging (MRI) is widely used in study of maxillofacial structures. While MRI is the modality of choice for soft tissues, it fails to capture hard tissues such as bone and teeth. Virtual dental models, acquired by optical 3D scanners, are becoming more accessible for dental practice and are starting to replace the conventional dental impressions. The goal of this research is to fuse the high-resolution 3D dental models with MRI to enhance the value of imaging for applications where detailed analysis of maxillofacial structures are needed such as patient examination, surgical planning, and modeling.

Methods

A subject-specific dental attachment was digitally designed and 3D printed based on the subject's face width and dental anatomy. The attachment contained 19 semi-ellipsoidal concavities in predetermined positions where oil-based ellipsoidal fiducial markers were later placed. The MRI was acquired while the subject bit on the dental attachment. The spatial position of the center of mass of each fiducial in the resultant MR Image was calculated by averaging its voxels' spatial coordinates. The rigid transformation to fuse dental models to MRI was calculated based on the least squares mapping of corresponding fiducials and solved via singular-value decomposition.

Results

The target registration error (TRE) of the proposed fusion process, calculated in a leave-one-fiducial-out fashion, was estimated at 0.49 mm. The results suggest that 6–9 fiducials suffice to achieve a TRE of equal to half the MRI voxel size.

Conclusion

Ellipsoidal oil-based fiducials produce distinguishable intensities in MRI and can be used as registration fiducials. The achieved accuracy of the proposed approach is sufficient to leverage the merged 3D dental models with the MRI data for a finer analysis of the maxillofacial structures where complete geometry models are needed.



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