Early-stage COVID-19 pandemic observations on pulmonary embolism using nationwide multi-institutional data harvesting.

We introduce a multi-institutional data harvesting (MIDH) method for longitudinal observation of medical imaging utilization and reporting. By tracking both large-scale utilization and clinical imaging results data, the MIDH approach is targeted at measuring surrogates for important disease-related observational quantities over time. To quantitatively investigate its clinical applicability, we performed a retrospective multi-institutional study encompassing 13 healthcare systems throughout the United States before and after the 2020 COVID-19 pandemic. Using repurposed software infrastructure of a commercial AI-based image analysis service, we harvested data on medical imaging service requests and radiology reports for 40,037 computed tomography pulmonary angiograms (CTPA) to evaluate for pulmonary embolism (PE). Specifically, we compared two 70-day observational periods, namely (i) a pre-pandemic control period from 11/25/2019 through 2/2/2020, and (ii) a period during the early COVID-19 pandemic from 3/8/2020 through 5/16/2020. Natural language processing (NLP) on final radiology reports served as the ground truth for identifying positive PE cases, where we found an NLP accuracy of 98% for classifying radiology reports as positive or negative for PE based on a manual review of 2,400 radiology reports. Fewer CTPA exams were performed during the early COVID-19 pandemic than during the pre-pandemic period (9806 vs. 12,106). However, the PE positivity rate was significantly higher (11.6 vs. 9.9%, p < 10-4) with an excess of 92 PE cases during the early COVID-19 outbreak, i.e., ~1.3 daily PE cases more than statistically expected. Our results suggest that MIDH can contribute value as an exploratory tool, aiming at a better understanding of pandemic-related effects on healthcare.

Association of tibialis posterior tendon pathology with other radiographic findings in the foot: a case-control study.

The purpose of this study was to analyze the prevalence of spring ligament pathology and other radiographic changes related to flatfoot deformity in the presence of different degrees of tibialis posterior tendon pathology. A total of 72 patients (24 with tibialis posterior tendon abnormality and 48 sex- and age-matched controls) were evaluated for tibialis posterior tendon pathology, spring ligament pathology, and plain pedal radiographic angles, including cuboid abduction, talar declination, calcaneal inclination, and Meary's angles. The patients with tibialis posterior tendon pathology were subdivided into either minor (Type I) or severe (Type II/III), according to the Conti classification of tibialis posterior tendon pathology on MRI. All the continuous data of radiographic angles were dichotomized into either a flatfoot group or normal/cavus foot group. Associations between these nominal variables were analyzed. There was no association between Type I tibialis posterior tendon pathology and spring ligament pathologies (OR = 0.8, 95% CI = 0.15-4.65). Conversely, every patient with Type II/III tibialis posterior tendon pathology had spring ligament abnormality. Type II/III group also showed statistically significant associations with both increased talar declination angle (OR = 10.4, 95% CI = 1.62-109.22) and Meary's angle (OR = 7.5, 95% CI = 1.35-51.12), while no such associations were found with Type I tibialis posterior tendon pathology (OR = 1.0, 95% CI = 0.18-6.18 with talar declination angle; OR = 3.9, 95% CI = 0.65-27.71 with Meary's angle). In this investigation, only advanced tibialis posterior tendon pathology was statistically significantly associated with adult-acquired flatfoot deformity and spring ligament pathology.

Pellegrini-Stieda disease: a heterogeneous disorder not synonymous with ossification/calcification of the tibial collateral ligament-anatomic and imaging investigation.

OBJECTIVE: Ossification/calcification around the medial femoral condyle has been known as Pellegrini-Stieda (PS) disease for almost 100 years. Little attention has been given to magnetic resonance (MR) imaging characteristics. Our purpose is to demonstrate the anatomy in the medial femoral compartment and imaging findings of PS disease, determining the sites and patterns of ossification. DESIGN AND PATIENTS: In a cadaveric study seven specimens were dissected to show the anatomic relations of the tibial collateral ligament (TCL) and the tendon of the ischiocondylar part of the adductor magnus muscle, in the medial femoral epicondyle. In order to determine the nature of ossification/calcification in PS disease, MR imaging and radiographic findings in nine patients were analyzed by two observers with attention to the specific site, shape, and orientation of the ossification and its relationship to the tibial collateral ligament (TCL) and adductor magnus tendon. Available clinical history was recorded. A classification system addressing different sites and patterns of ossification was developed. RESULTS: The anatomic study showed that the TCL and the adductor magnus tendon insert at different sites in the medial femoral condyle and there is no continuation; however, some fibers of the posterior bundle of the TCL overlap the anterior aspect of the adductor magnus tendon. The imaging study showed that shape, orientation, and location of the abnormal calcification and ossification were similar on radiographic and MR imaging analysis. Ossification had an inferior orientation in six cases, a superior orientation in two cases, and both in one case. Four patterns of ossification were noted: (I) a beak-like appearance with an inferior orientation and femoral attachment was present in five cases; (II) a drop-like appearance with an inferior orientation, parallel to the femur, was evident in one case; (III) an elongated appearance with a superior orientation, parallel to the femur, was seen in two cases; and (IV) a beak-like appearance with an inferior and superior orientation, attached to the femur, was seen in one case. The ossification was present in the TCL in six cases, in the adductor magnus tendon in two cases, and in both in one case. The coronal plane was best in detecting and categorizing the ossification. CONCLUSION: Our data indicate that ossification in PS disease is not confined to the TCL but may also involve the adductor magnus tendon. In some cases, it can be related to the anatomic proximity (overlap) of the fibers of these two structures. PS disease should not be regarded as synonymous with ossification of the TCL. The ossification may be classified into four types. No clinical differences among these types appear to exist.

Hydroxyapatite crystal deposition disease.

Hydroxyapatite (HA) crystal deposition disease (HADD) is a well-recognized systemic disease of unknown etiology that is caused by para-articular and/or intra-articular deposition of HA crystals. The disease is clinically manifested by localized pain, swelling, and tenderness about the affected joint along with variable limitation of joint motion, although not all patients are symptomatic. Plain radiographs may show calcifications of varying size and shape in the para-articular tendons, bursae, and capsule. The disease may be mono- or polyarticular in distribution. The shoulder is most commonly involved with calcification in the supraspinatus tendon. When intra-articular, HA crystals can cause joint destruction. Any joint can be involved; the shoulder is most commonly affected, resulting in "Milwaukee shoulder." Treatment of HADD usually requires use of analgesics, local heat, needling with or without aspiration of the calcific deposits, steroid injections, and, at times, even surgery for relief of pain.