In vivo evaluation of human patellar tendon microstructure and microcirculation with diffusion MRI.

BACKGROUND: Patellar tendon (PT) microstructure integrity and microcirculation status play a crucial role in the progression of tendinopathy and tendon repair. PURPOSE: To assess the feasibility and robustness of stimulated-echo based diffusion-weighted MRI with readout-segmented echo-planar imaging (ste-RS-EPI) for noninvasive assessment of microstructure and microcirculation of human PT. STUDY TYPE: Prospective. SUBJECTS: Fifteen healthy volunteers. FIELD STRENGTH/SEQUENCE: PT diffusion tensor imaging (DTI) and intravoxel incoherent motion (IVIM) were acquired with an ste-RS-EPI protocol on a 3T MRI scanner. ASSESSMENT: Subjects were positioned with their PT at the magic angle. DTI-derived parameters including axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), and fractional anisotropy (FA) were estimated with b-values of 0 and 800 s/mm2 and 12 diffusion directions. IVIM-derived parameters, f p , D* × f p , V b , and D* × V b were assessed in the central-third and the outer-two thirds of the PT with b-values of 0, 20, 30, 60, 80, 120, 200, 400, and 600 s/mm2 in three orthogonal directions. STATISTICAL TESTS: Paired t-tests were used to evaluate differences in IVIM parameters between the central-third and outer-two thirds regions of the patellar tendon. Paired t-tests and within-subject coefficient of variation were used to assess the intra- and intersession reproducibility of PT DTI and IVIM parameters. RESULTS: DTI parameters for healthy PT were 1.54 ± 0.09 × 10-3 mm2 /s, 1.01 ± 0.05 × 10-3 mm2 /s, 1.18 ± 0.06 × 10-3 mm2 /s, and 0.30 ± 0.04 for AD, RD, MD, and FA, respectively. Significantly higher (P < 0.05) IVIM parameters f p and D* × f p were observed in the outer-two thirds (6.1% ± 2.4% and 95.2 ± 49.6, respectively) compared with the central-third (3.8% ± 2.3% and 48.6 ± 35.2, respectively) of the PT. DATA CONCLUSION: Diffusion MRI of PT with an ste-RS-EPI protocol is clinically feasible. Both DTI- and IVIM-derived parameters of the PT demonstrated good test-retest reproducibility and interrater reliability. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:780-790.

Severity of heterotopic ossification in patients following surgery for hip fracture: a retrospective observational study.

BACKGROUND: Heterotopic ossification (HO) is a relatively common complication following hip surgery treated with open reduction and internal fixation, total arthroplasty or hemiarthroplasty. Development of HO after hip surgery is an important clinical issue as it can affect functional status. We aimed to determine whether there was association between severity of heterotopic ossification about the hip and the interval between the time of hip fracture and surgery. MATERIALS AND METHODS: Our retrospective study included 151 patients (age range 33-95 years) treated for hip fractures by hemiarthroplasty. Medical records were reviewed for time interval to surgery, laterality, surgical approach, and patient age. Patients who had any post-operative complications were excluded. Radiographs were semiquantitatively assessed for the degree of heterotopic ossification based on Brooker Classification (5-point scale). Statistical analysis was performed utilizing Chi-square, Kruskal-Wallis, and Score tests, and also a proportional odds model (significance level set at 0.05). RESULTS: Thirty eight patients had no heterotopic ossification, 43 had class 1, 55 had class 2, and 15 had class 3 or greater heterotopic ossification. The majority of patients (59.6%) had surgery within 2 days of acute injury. Severe heterotopic ossification (HO 3+) was associated with the longer interval between the time of acute hip fracture and surgery (median 6 days) vs. median 2 days in all other groups (HO classes 0-2) (p = 0.0015). The odds ratio and 95% CI for one level higher HO class was 1.296 (1.152, 1.459), which meant that the odds of having HO class one level higher increased by about 29.6% for every one-day increase in the days to surgery. No significant association was found for other variables. CONCLUSION: Class 3 or greater HO was associated with longer time interval between time of acute hip fracture and surgery compared to all other groups (HO class 0-2).

Intravoxel incoherent motion (IVIM) imaging in human achilles tendon.

BACKGROUND: Limited microcirculation has been implicated in Achilles tendinopathy and may affect healing and disease progression. Existing invasive and noninvasive approaches to evaluate tendon microcirculation lack sensitivity and spatial coverage. PURPOSE: To develop a novel Achilles tendon intravoxel incoherent motion (IVIM) MRI protocol to overcome the limitations from low tendon T2 /T2 * value and low intratendinous blood volume and blood velocity to evaluate tendon microcirculation. STUDY TYPE: Prospective. SUBJECTS: Sixteen healthy male participants (age 31.0 ± 2.1) were recruited. FIELD STRENGTH/SEQUENCE: A stimulated echo readout-segmented echo planar imaging (ste-RS-EPI) IVIM sequence at 3.0T. ASSESSMENT: The feasibility of the proposed ste-RS-EPI IVIM protocol combined with Achilles tendon magic angle effect was evaluated. The sensitivity of the protocol was assessed by an exercise-induced intratendinous hemodynamic response in healthy participants. The vascular origin of the observed IVIM signal was validated by varying the diffusion mixing time and echo time. STATISTICAL TESTS: Two-tailed t-tests were used to evaluate differences (P < 0.05 was considered significant). RESULTS: Consistent with known tendon hypovascularity, the midportion Achilles tendon at baseline showed significantly lower IVIM-derived perfusion fraction (fp ) (3.1 ± 0.9%) compared to the proximal and distal Achilles tendon (6.0 ± 1.8% and 6.1 ± 2.0%, respectively; P < 0.01). Similarly, the midportion Achilles tendon exhibited significantly lower baseline blood flow index (D*×fp ) (40.9 ± 19.2, 18.3 ± 5.3, and 32.0 ± 9.4 in proximal, midportion, and distal Achilles tendon, respectively; P < 0.01). Eccentric heel-raise exercise led to ∼2 times increase of Achilles tendon blood flow in healthy participants. Consistent with its vascular origin, the estimated fp demonstrated a high dependency to IVIM protocol parameters, while the T1 /T2 -corrected absolute intratendinous microvascular blood volume fraction (Vb ) did not vary. DATA CONCLUSION: Achilles tendon ste-RS-EPI IVIM noninvasively assessed baseline values and exercise-induced changes to tendon microcirculation in healthy tendon. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1690-1699.

A Rare Incidence of Pigmented Villonodular Synovitis of the Ankle in an Adolescent.

Pigmented villonodular synovitis mostly affects the knee and other large joints such as the hip. Although the disease is most commonly found in adult patients aged 30 to 40 years, rare cases in children and the elderly have been reported. We present the case of an 11-year-old female who was found to have biopsy-proven pigmented villonodular synovitis in her subtalar joint in 2012. Five years after surgical excision, the patient has continued to be involved in competitive dancing and cheerleading without any pain in her ankle. Moreover, follow-up magnetic resonance imaging studies showed no evidence of recurrence. Our case report emphasizes that the disease should not be solely considered in the middle-age population but should be included in the differential diagnosis of the pediatric patient.

Ethical Issues in Radiology Journalism, Peer Review, and Research.

OBJECTIVE: Although some research and publication practices are clearly unethical, including fraud and plagiarism, other areas of research and publication, such as informed consent and conflicts of interest, fall into grayer areas. CONCLUSION: The purposes of this article are, therefore, to review a variety of relevant ethical issues in radiology-related journalism, peer review, and research; to review the radiology literature to date that has addressed these issues; and to present position statements and potential solutions to these problems.

Necrotizing fasciitis and its mimics: what radiologists need to know.

OBJECTIVE: The purpose of this article is to review the imaging features of necrotizing fasciitis and its potential mimics. Key imaging features are emphasized to enable accurate and efficient interpretation of variables that are essential in appropriate management. CONCLUSION: Necrotizing fasciitis is a medical emergency with potential lethal outcome. Dissecting gas along fascial planes in the absence of penetrating trauma (including iatrogenic) is essentially pathognomonic. However, the lack of soft-tissue emphysema does not exclude the diagnosis. Mimics of necrotizing fasciitis include nonnecrotizing fasciitis (eosinophilic, paraneoplastic, inflammatory (lupus myofasciitis, Churg-Strauss, nodular, or proliferative), myositis, neoplasm, myonecrosis, inflammatory myopathy, and compartment syndrome. Necrotizing fasciitis is a clinical diagnosis, and imaging can reveal nonspecific or negative findings (particularly during the early course of disease). One should be familiar with salient clinical and imaging findings of necrotizing fasciitis to facilitate a more rapid and accurate diagnosis and be aware that its diagnosis necessitates immediate discussion with the referring physician.

Osteochondroma of the hip with adjacent bursal chondromatosis.

It is well established that irregular bursae can form adjacent to an osteochondroma (bursa exostotica) as a result of mechanical irritation and that these bursae can be complicated by inflammation, hemorrhage, or infection. Bursal chondromatosis is a rare complication, with only seven published cases in the literature according to our searches. We present the case of a 53-year-old female who presented with slowly progressive left hip/thigh pain and was found to have an osteochondroma arising from the lesser trochanter with numerous ossified bodies in the adjacent soft tissues. MRI demonstrated osteochondral bodies in a fluid-filled bursa adjacent to the osteochondroma, with several of the bodies noted to be fairly displaced from the osteochondroma cartilaginous cap. At surgery, the osteochondroma was removed and numerous bodies of varying sizes were excised, some of which were noted to be adherent to the bursal lining and others that were separated/distant from the cartilage cap. The question arises as to whether this process represents bursal chondromatosis resulting from benign neoplasia of cells lining the abnormal bursa, "cartilage shedding" from the osteochondromatous cap, or both. The purpose in presenting this case is to introduce a rare complication of an osteochondroma, demonstrate that soft tissue calcification and osteochondral densities displaced from an underlying osteochondroma are not always the result of sarcomatous degeneration, and provide support for the theory that cells lining a bursa in a nonphysiologic location can undergo benign neoplasia with subsequent formation of osteochondral bodies.

Exploring Dual-Energy CT Spectral Information for Machine Learning-Driven Lesion Diagnosis in Pre-Log Domain.

In this study, we proposed a computer-aided diagnosis (CADx) framework under dual-energy spectral CT (DECT), which operates directly on the transmission data in the pre-log domain, called CADxDE, to explore the spectral information for lesion diagnosis. The CADxDE includes material identification and machine learning (ML) based CADx. Benefits from DECT's capability of performing virtual monoenergetic imaging with the identified materials, the responses of different tissue types (e.g., muscle, water, and fat) in lesions at each energy can be explored by ML for CADx. Without losing essential factors in the DECT scan, a pre-log domain model-based iterative reconstruction is adopted to obtain decomposed material images, which are then used to generate the virtual monoenergetic images (VMIs) at selected n energies. While these VMIs have the same anatomy, their contrast distribution patterns contain rich information along with the n energies for tissue characterization. Thus, a corresponding ML-based CADx is developed to exploit the energy-enhanced tissue features for differentiating malignant from benign lesions. Specifically, an original image-driven multi-channel three-dimensional convolutional neural network (CNN) and extracted lesion feature-based ML CADx methods are developed to show the feasibility of CADxDE. Results from three pathologically proven clinical datasets showed 4.01% to 14.25% higher AUC (area under the receiver operating characteristic curve) scores than the scores of both the conventional DECT data (high and low energy spectrum separately) and the conventional CT data. The mean gain >9.13% in AUC scores indicated that the energy spectral-enhanced tissue features from CADxDE have great potential to improve lesion diagnosis performance.

Evaluation of radiation dose among patients admitted through a university hospital emergency department.

This study was conducted to evaluate the impact of different patient presentations/characteristics on medical imaging and radiation exposure. We collected data on the estimated effective radiation dose (EED) of patients admitted through our University Hospital ER, and analyzed the relationships of patient gender, age, admitting diagnosis, and admission duration on EED. All (592) patients admitted through our ER (with imaging) during 1-week periods in May/November 2009 were included. To compare EEDs according to admission diagnosis, seven categories were created: Cardiopulmonary, Gastrointestinal, Genitourinary, Neurologic, Trauma, Infectious, and Other. EEDs of patients with various admission durations were also evaluated. Units for all EEDs are mSv. Median EED (MEED) for all patients was 4.5. Males (7.8, females = 2.5) and adults (6.1, pediatrics = 1.8) experienced higher MEEDs, but significance was lost after controlling for other variables. MEED increased with admission duration (0.1 for <24 h, 1.8 for 1-3 days and 92.0 for >2 months). Trauma patients experienced the highest MEED (18.3), while patients with gastrointestinal/genitourinary diagnoses experienced the second highest MEED (13.0 mSv for both). Pediatric/male patients experienced heightened radiation exposure, but these relationships were largely due to other variables (higher male frequency/severity of trauma, pediatric patients had shorter admissions and diagnoses requiring less radiologic workup). Patients admitted following trauma and for prolonged durations showed elevated radiation exposure even after adjustment for all other variables. The identification of these relationships may aid in the development and focusing of future radiation awareness/reduction efforts to persons involved in the evaluation and care of patients with these presentations and characteristics.

Granulomatous salmonella osteomyelitis associated with anti-tumor necrosis factor therapy in a non-sickle cell patient: a case report.

Salmonella osteomyelitis is seen most commonly in patients with sickle cell disease and in those with compromised immune systems. We report on the clinical, histological and imaging findings of salmonella osteomyelitis with intraosseous abscess formation occurring in a non-sickle cell patient receiving anti-tumor necrosis factor (TNF) alpha therapy.

Diffusion tensor imaging of peripheral nerves.

Magnetic resonance diffusion tensor imaging (DTI) allows the directional dependence of water diffusion to be studied. Analysis of the resulting image data allows for the determination of fractional anisotropy (FA), apparent diffusion coefficient (ADC), as well as allowing three-dimensional visualization of the fiber tract (tractography). We visualized the ulnar nerve of ten healthy volunteers with DTI. We found FA to be 0.752 ± 0.067 and the ADC to be 0.96 ± 0.13 × 10(-3) mm(2)/s. A nuts-and-bolts description of the physical aspects of DTI is provided as an educational process for readers.

Spontaneous osteonecrosis of the knee (SONK): The role of MR imaging in predicting clinical outcome.

BACKGROUND/AIM: We try to investigate the association between patterns of imaging findings in patients who had a diagnosis of subchondral fracture around the knee, formerly known as SONK and their clinical outcome. MATERIALS AND METHODS: We retrospectively identified 43 knees of 37 patients (28 males, 15 females) who had diagnosis of subchondral fractures around the knee. The mean age is 56-year-old (range 17-83). Musculoskeletal fellowship trained radiologist evaluated all 43 knee MRI in: 1)location of marrow edema 2)peri-osseous edema; 3) subchondral fracture line; 4) subchondral articular surface contour; 5)meniscal tear and extrusion; 6)adjacent soft tissue edema; 7) joint effusion. Independent clinical chart review was performed for clinical outcome with follow up time average of 13.3 months (range 0-88 months). Bad outcome was defined as worsening on imaging, continued complaint with surgical management and knee replacement or another episode of SONK. Chi-square analysis and Student's T tests were conducted to test the statistical significance of association between MR findings and outcomes. Statistical significance was set at p = 0.05 level. RESULTS: Of 43 knees, 6 patients had another episodes of SONK (14%), 11 patients were not improving or needed injection vs arthroscopy (26%), 4 patients required arthroplasty (9%), 22 patients had no negative outcome (51%). Gender, age, diabetic status, and location of the subchondral fracture show no influence on outcome. Worse outcome group had a significantly higher average BMI (31.7 vs. 28.0, P = 0.02). Positive change of subchondral articular surface contour is the only imaging finding with positive association with worse outcome (80% vs. 39.9%, P = 0.02). Presence of positive findings of above 3), 4), 5) and 6) had higher percentage of bad outcome (77.8%) compared to those with less positive findings (47.2%). CONCLUSION: MR imaging findings may help at identifying SONK patient with potential risk of developing bad outcome.

Ultrasonographic measurement of femoral cartilage thickness in type II diabetic patients.

The aim of this study is to compare the distal femoral cartilage thickness of patients with type II diabetes mellitus with those of healthy subjects using ultrasonography. The study comprised 34 patients and 36 healthy subjects. Demographic characteristics of all the participants were recorded. The thickness of the femoral articular cartilage was measured using a 5-18MHzlinearprobe.Measurements were performed bilaterally from three points (intercondylar area, medial condyle, and lateral condyle). No significant difference could be found between patients and healthy subjects. Two demographic characteristics correlated positively with diabetic patients.

Digital papillary adenocarcinoma: a case report.

Digital papillary adenocarcinoma (DPAc) is a relatively rare neoplasm arising from the sweat glands with a predilection for the hand. A case of DPAc in the third finger at the level of the proximal phalanx in a 55-year-old male is presented. Our paper recommends specific consideration of DPAc in evaluating digital soft tissue masses, particularly those that present with an aggressive nature.

Giant cell tumour of the distal phalanx of the hand.

Giant cell tumour of bone in the phalanx of the hand is extremely rare. A case of giant cell tumour of distal phalanx treated with a ray amputation is presented.

Soft tissue aneurysmal bone cyst: a rare case in a middle aged patient.

Soft tissue aneurysmal bone cyst is a rare entity, with about 20 cases reported in literature, only 3 of which are in patients over 40 years of age. We present a case of a 41 year old Latin American female who presented for evaluation of atraumatic chest pain with radiation to the left shoulder. Her initial workup was negative, including radiographic imaging of the chest and left shoulder. 4 months later, she presented to her orthopedic surgeon with a palpable mass and mild left shoulder pain. Radiographs acquired at that time demonstrated a 7.0 × 5.5 × 6.7 cm mass with rim calcification in the region of the upper triceps muscle. Subsequent CT imaging showed central areas of hypodensity and thin septations, a few of which were calcified. MR evaluation showed hemorrhagic cystic spaces with multiple fluid-fluid levels and enhancing septations. Surgical biopsy was performed and pathology was preliminarily interpreted as cystic myositis ossificans, however on final review the diagnosis of soft tissue aneurysmal bone cyst was made. The lesion was then surgically excised and no evidence of recurrence was seen on a 3 year post-op radiograph. Following description of our case, we conduct a literature review of the imaging characteristics, diagnosis, and treatment of soft tissue aneurysmal bone cyst.

Presacral myelolipoma: a case report and review of imaging findings.

Extra-adrenal myelolipoma is a relatively rare entity, with fewer than 50 cases reported in literature. We present a case of a 79 year-old female who presented for evaluation of hip fracture following trauma, where a lobulated presacral mass with mixed fat/soft tissue attenuation was incidentally seen on initial bone algorithm pelvic CT. Subsequent MRI showed signal characteristics of a lesion with mixed fat and soft tissue composition. The lesion demonstrated stability on follow-up imaging. An elective surgical resection was performed which yielded a grossly fatty mass. The diagnosis of presacral myelolipoma was confirmed on microscopic examination. Following description of our case, we conduct a literature review of the imaging characteristics, diagnosis, and treatment of presacral myelolipoma.

Multitendon xanthomatosis in a normo-cholesterolemic patient.

We present a rare case of multisite xanthomatosis occurring in a 38-year-old normocholesterolemic man without a familial history. More commonly, these conditions are associated with familial hypercholesterolemia and cerebrotendinous xanthomatosis. Tendon xanthomas should prompt clinicians to perform a thorough investigation of the patient's metabolic panel and family history. Rarely, these conditions occur in patients without demonstrable dysmetabolic state. The characteristic MR imaging findings are presented in conjunction with review of the literature.

Metatarsal Coalition Complicated by Interdigital Neuroma.

We present the case of a 20-year-old man with the chief complaint of right foot pain for the past three years presenting with focal bony prominence at dorsomedial aspect of right mid foot with interdigital pain. MRI demonstrated a metatarsal coalition with interdigital neuroma.