Faculty Bibliography

Background MRI is a powerful diagnostic tool with a long acquisition time. Recently, deep learning (DL) methods have provided accelerated high-quality image reconstructions from undersampled data, but it is unclear if DL image reconstruction can be reliably translated to everyday clinical practice. Purpose To determine the diagnostic equivalence of prospectively accelerated DL-reconstructed knee MRI compared with conventional accelerated MRI for evaluating internal derangement of the knee in a clinical setting. Materials and Methods A DL reconstruction model was trained with images from 298 clinical 3-T knee examinations. In a prospective analysis, patients clinically referred for knee MRI underwent a conventional accelerated knee MRI protocol at 3 T followed by an accelerated DL protocol between January 2020 and February 2021. The equivalence of the DL reconstruction of the images relative to the conventional images for the detection of an abnormality was assessed in terms of interchangeability. Each examination was reviewed by six musculoskeletal radiologists. Analyses pertaining to the detection of meniscal or ligament tears and bone marrow or cartilage abnormalities were based on four-point ordinal scores for the likelihood of an abnormality. Additionally, the protocols were compared with use of four-point ordinal scores for each aspect of image quality: overall image quality, presence of artifacts, sharpness, and signal-to-noise ratio. Results A total of 170 participants (mean age ± SD, 45 years ± 16; 76 men) were evaluated. The DL-reconstructed images were determined to be of diagnostic equivalence with the conventional images for detection of abnormalities. The overall image quality score, averaged over six readers, was significantly better (P < .001) for the DL than for the conventional images. Conclusion In a clinical setting, deep learning reconstruction enabled a nearly twofold reduction in scan time for a knee MRI and was diagnostically equivalent with the conventional protocol. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Roemer in this issue.

OBJECTIVE:Deep Learning (DL) image reconstruction has the potential to disrupt the current state of MR imaging by significantly decreasing the time required for MR exams. Our goal was to use DL to accelerate MR imaging in order to allow a 5-minute comprehensive examination of the knee, without compromising image quality or diagnostic accuracy. METHODS:A DL model for image reconstruction using a variational network was optimized. The model was trained using dedicated multi-sequence training, in which a single reconstruction model was trained with data from multiple sequences with different contrast and orientations. Following training, data from 108 patients were retrospectively undersampled in a manner that would correspond with a net 3.49-fold acceleration of fully-sampled data acquisition and 1.88-fold acceleration compared to our standard two-fold accelerated parallel acquisition. An interchangeability study was performed, in which the ability of 6 readers to detect internal derangement of the knee was compared for the clinical and DL-accelerated images. RESULTS:The study demonstrated a high degree of interchangeability between standard and DL-accelerated images. In particular, results showed that interchanging the sequences would result in discordant clinical opinions no more than 4% of the time for any feature evaluated. Moreover, the accelerated sequence was judged by all six readers to have better quality than the clinical sequence. CONCLUSIONS:An optimized DL model allowed for acceleration of knee images which performed interchangeably with standard images for the detection of internal derangement of the knee. Importantly, readers preferred the quality of accelerated images to that of standard clinical images.

Purpose: Image-guided joint aspiration is often requested for clinically suspected periprosthetic joint infection (PJI). For "dry taps" when no native joint fluid can be aspirated, a lavage with non-bacteriostatic saline can be performed. The purpose of this study is to determine the diagnostic utility of lavage versus native joint fluid aspiration in the setting of clinically suspected PJI. Materials and Methods: IRB approval was obtained and informed consent was waived for this retrospective study. A PACS search from 2011- 2017 for image-guided aspirations yielded 918 procedures, of which 630 were excluded for non-articular and non-arthroplasty aspirations, antibiotic cement spacers, and lack of clinical information in the electronic medical record. The study cohort included 288 procedures from 173 patients who underwent operative or non-operative management. The reference standard was the intraoperative culture for operative patients and clinical follow-up for conservatively managed patients. A Fisher exact test was used for statistical analysis. Results: The study cohort consisted of 98 females, 75 males, mean age 64 (range 34-90) with the following arthroplasty types: 176 hips, 65 knees, and 47 shoulders. Of 288 procedures, 105 were performed with lavage and 183 were native joint fluid aspirations; 112 were subsequently operatively managed. The mean follow-up for non-operative patients was 5 months (range 0-42). For native joint fluid aspiration versus lavage, accuracy was 81% vs. 73% (p=0.14), sensitivity was 58% vs. 28% (p=0.03), specificity was 88% vs. 91% (p=0.66), negative predictive value was 89% vs. 77% (p=0.02), and positive predictive value was 55% vs. 53% (p=1.00), respectively. Conclusion: Lavage is less sensitive with a lower negative predictive value for the diagnosis of PJI compared to native joint fluid aspirations, possibly due to a lower pretest probability of infection and the inherent dilutional effects of the procedure

RATIONALE AND OBJECTIVES: Correlation of imaging studies and reference standard outcomes is a significant challenge in radiology. This study evaluates the effectiveness of a new communication tool by assessing the ability of this system to correctly match the imaging studies to arthroscopy reports and qualitatively assessing radiologist behavior before and after the implementation of this system. MATERIALS AND METHODS: Using a commercially available communication or educational tool and applying a novel matching rule algorithm, radiology and arthroscopy reports were matched from January 17, 2017 to March 1, 2017 based on anatomy. The interpreting radiologist was presented with email notifications containing the impression of the imaging report and the entire arthroscopy report. Total correlation rate of appropriate report pairings, modality-specific correlation rate, and the anatomy-specific correlation rate were calculated. Radiologists using the system were given a survey. RESULTS: Overall correlation rate for all musculoskeletal imaging was 83.1% (433 or 508). Low correlation was found in fluoroscopic procedures at 74.4%, and the highest correlation was found with ultrasound at 88.4%. Anatomic location varied from 51.6% for spine to 98.8% for hips and pelvis studies. Survey results revealed 87.5% of the respondents reporting being either satisfied or very satisfied with the new communication tool. The survey also revealed that some radiologists reviewed more cases than before. CONCLUSIONS: Matching of radiology and arthroscopy reports by anatomy allows for excellent report correlation (83.1%). Automated correlation improves the quality and efficiency of feedback to radiologists, providing important opportunities for learning and improved accuracy.

Soft-tissue augmentation and implants are increasingly seen by the radiologist as more techniques emerge for a variety of indications and locations. Some surgical and implant procedures are performed for purely cosmetic reasons in otherwise healthy patients seeking to improve their body image, and some are performed for reconstruction after cancer or other chronic illnesses. Abdominoplasty, liposuction, and autologous fat grafting can be performed for abdominal and gluteal contouring. Injection of liquid injectable silicone has historically been fraught with legal issues, although it continues to be used for augmentation in a variety of anatomic locations. Newer solid silicone implants have revolutionized cosmetic and reconstructive muscular contouring. Subdermal implants placed by nonmedical professionals are relatively new and unrecognized within the medical establishment, although such implants have been described in the popular culture. Perhaps the most rapidly increasing segment of cosmetic procedures, however, is minimally invasive cosmesis in the form of soft-tissue fillers in the hands and face. Finally, the major principles of breast augmentation and penile implants are also reviewed. Regardless of the location and the type of implant, complications of plastic surgery and soft-tissue implants can generally be classified into the following categories: seroma, hematoma, infection, migration, vascular or nerve compression, fibrosis, foreign-body reaction, and rupture or breakdown. Key concepts include knowing the appropriate anatomic location and the normal postoperative appearance so that complications can be properly detected. A broad range of approved, off-label, and illicit plastic surgical and implant procedures are described and their complications illustrated with cases with classic imaging findings. (c)RSNA, 2017.

OBJECTIVE: The purpose of this study was to compare the diagnostic performance of a 5-minute shoulder MRI protocol consisting of multiplanar 2D fast spin-echo (FSE) sequences with parallel imaging to that of a standard shoulder MRI protocol. MATERIALS AND METHODS: A retrospective review of 151 3-T MRI examinations of shoulders of 147 patients (mean age, 46.95 years) and 50 1.5-T MRI examinations of shoulders of 50 patients (mean age, 53.74 years) with four fast and five standard sequences from two academic centers between January 2014 and April 2015 was performed by three musculoskeletal radiologists. Interchangeability of fast and standard MRI was tested by comparing interprotocol (fast vs standard) interreader agreement with standard MRI interreader agreement. Interreader agreement was also compared using kappa statistics. The frequency of major findings was compared using an adjusted McNemar test. Sensitivity and specificity of MRI were measured for 51 patients who underwent surgery. RESULTS: Interprotocol reader agreement was essentially equal to reader agreement on standard MRI (mean difference /= 0.08). Sensitivities of fast MRI for tendon and labral tears (33-92%) were equivalent or higher than those of standard MRI with similar specificities (77-98%). CONCLUSION: Fast 5-minute shoulder MRI with multiplanar 2D FSE sequences using parallel imaging is interchangeable, with similar interreader agreement and accuracy, with standard shoulder MRI for evaluating shoulder injuries.

Purpose: Quantification of tendon retraction is paramount in the surgical decision-making algorithm for proximal hamstring avulsion injury. Not only is it used to determine if surgery is indicated, but it may lead the surgeon to change the pre-operative plan from a more aesthetically-appealing gluteal fold incision to a more extensile, longitudinally-based proximal thigh incision. However, the hamstring origin on the ischial tuberosity is broad. Variability in location on the ischial tuberosity used as the proximal landmark and occasional difficulty in locating the proximal tendon stump may lead to differences in perceived retraction, altering the surgical decision making process. We hypothesize there will be substantial variability in the ischial tuberosity location used as the proximal marker, not only between orthopaedists and radiologists, but also amongst radiologists themselves. Materials and Methods: Two surveys were created for the purpose of this study. One survey was sent to members of the Society of Skeletal Radiology (SSR), querying the preferred ischial tuberosity landmark, perceived difficulties in quantifying retraction, and the impact of radiology measurements on clinical decision making. A similar survey, with added questions on the impact of imaging findings in clinical management was approved and posted onto the American Orthopaedic Society for Sports Medicine (AOSSM) website. Results: Two hundred and fifteen SSR members responded to the survey. For cases of complete and partial hamstring avulsion, there was variability among musculoskeletal (MSK) radiologists in the proximal landmark used for quantification of retraction, with n = 100 (47%) using the conjoint tendon origin, n = 84 (39%) using the semimembranosus tendon origin, and n = 31(14%) using the posterior-inferior edge of the ischial tuberosity. Difficulty in determining location of the retracted tendon stump was reported by n = 93(44%) of MSK radiologists. Most MSK radiologists (n = 118, 55%) reported measurements in their dictation and were unsure as to whether or not they are used to guide clinical management. Results of the second survey posted by AOSSM will be subsequently reported when available. Conclusion: Differences in choosing an ischial tuberosity landmark and occasional difficulty in locating the proximal tendon stump may lead to substantial variability in measured tendon retraction among MSK radiologists in cases of proximal hamstring avulsion. Radiologists should consider a standardized approach to measuring tendon retraction or should clearly stipulate the location of the proximal landmark in their reports

Purpose: Talocalcaneal coalition and medial ankle accessory muscles can both predispose to tarsal tunnel syndrome due to stretching and extrinsic compression of the posterior tibial nerve and its branches in the tarsal tunnel. We have anecdotally observed a high proportion of medial accessory ankle muscles in patients with talocalcaneal coalitions. The purpose of our study was to assess this previously unrecognized association with the hypothesis that this may be an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition. Materials and Methods: A search of our department imaging database, utilizing the keyword "coalition" yielded 79 cases. Images were retrospectively reviewed by two musculoskeletal (MSK) radiologists for the presence of medial ankle accessory muscles, including: accessory soleus, accessory flexor digitorum longus, and peroneocalcaneus internus. In addition, 30 cases, selected from the final cohort, were reviewed independently by two (MSK) readers to determine interobserver agreement utilizing the kappa coefficient. Results: The final cohort included 67 ankle MRIs in 65 patients, part of a cohort previously published describing the association of talocalcaneal coalitions and soft tissue pathology in the tarsal tunnel, (35 men, 30 women, age range 8-72 years, mean age, 40 years). Overall n = 14 (21%) of patients with talocalcaneal coalition had a medial sided accessory muscle, including accessory flexor digitorum longus muscle in 8 ankles (12% compared to 2-8% reported in the general population), a peroneocalcaneus internus in 4 ankles (6% compared to 1% reported in the general population) and an accessory soleus in 2 ankles (3% compared to 0.7-5.5% of the general population). The kappa coefficient was calculated as 0.61, demonstrating substantial agreement among readers in detecting medial accessory muscles. Conclusion: Medial sided accessory ankle muscles are more common in patients with talocalcaneal coalitions compared to the general population, with the most common muscle being the accessory flexor digitorum longus. It is important for radiologists to be aware of medial accessory muscles as an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition, a cohort already predisposed to compression of soft tissue structures by coalition related bony excrescences and hindfoot valgus deformity

STUDY DESIGN: Patients with preoperative spine magnetic resonance imaging (MRI) studies from a prospective multicenter study of operative adolescent Scheuermann kyphosis (SK). OBJECTIVES: To investigate the usefulness of MRI screening in operative planning for SK surgeries. SUMMARY OF BACKGROUND DATA: Neural axis abnormalities in operative SK have not been previously studied with MRI screening, despite its use. METHODS: One orthopedic surgeon and two radiologists evaluated all images retrospectively. Radiographs were evaluated for kyphosis apex and magnitude. MRIs were evaluated for spinal cord abnormalities, epidural lipomatosis, location and number of vertebral wedging, Schmorl nodes and posterior disc herniations, frequency of spondylolysis, etc. The relationship of these pathologies to the kyphosis apex was explored. This group was compared to a surgical SK group without preoperative MRIs. RESULTS: Eighty-six patients with MRIs, mean age 16.3 years, 64% male, and a mean preoperative kyphosis of 75.9 degrees were evaluated. There were 17 spinal cord abnormalities. Low-lying conus was found in 2 patients, and syrinx in 15 (no Chiari malformations). Epidural lipomatosis was found in 49 patients, average of 5.7 levels. Anterior vertebral wedging occurred in all (mean 4.7 levels). Posterior disc herniations averaged 5.2 levels/patient and 1.8 levels caudad to the apex. Spondylolysis was reported in 8.1%. Four cases (4.7%) had the operative plan changed as a result of the preoperative MRI: two due to neural compression, one due to disc herniation and one due to a spinal cord draped over the apex. Thirty-one patients did not receive an MRI; there were no significant differences between the two groups. The rate of postoperative neurologic change was 3.5% in the MRI group and 3.2% in the no-MRI group. CONCLUSIONS: Based on 4.7% of cases requiring a change in the operative plan as a result of preoperative MRI, the authors recommend considering performing screening MRI in operative SK patients.