Contrast flow in CT-guided lumbar interlaminar epidural steroid injections: does needle position effect the laterality of contrast flow?

PURPOSE: To evaluate the effect of needle position on the laterality of contrast flow in CT-guided lumbar interlaminar epidural steroid injections. MATERIALS AND METHODS: A retrospective review of consecutive CT-guided interlaminar lumbar epidural steroid injections was performed. The terminal needle tip position (midline or lateral) and the laterality of epidural contrast were evaluated by two readers. Contrast flow pattern was classified as ipsilateral to needle trajectory, bilateral, or contralateral. Bilateral flow was further divided into asymmetric, symmetrical, or asymmetric to the contralateral side. Inter-reader agreement was calculated with the kappa statistic. The relationship of needle position to contrast laterality was calculated with the chi statistic. Pain scores were compared for bilateral and unilateral flows with a two-tailed T test for independent means. RESULTS: A total of 250 injections were included in 204 patients, with an age range of 24 to 93 years. The most commonly injected level (145/250) was L4-L5. Agreement between the two readers was almost perfect and substantial (kappa 0.751-0.880). The majority of injections (154/250) demonstrated contrast flow ipsilateral to the needle trajectory, 90/250 demonstrated bilateral flow, and 6/250 had contralateral flow. Of the 90 cases with bilateral flow, 80% were performed with a midline terminal needle position (p < 0.001). There was no difference in immediate post-procedure pain scores between patients with ipsilateral or bilateral contrast flow. CONCLUSION: For interlaminar epidural steroid injections, a midline terminal needle tip position has a greater probability of producing bilateral contrast flow compared to a lateral terminal needle tip position.

Deep learning discrimination of rheumatoid arthritis from osteoarthritis on hand radiography.

PURPOSE: To develop a deep learning model to distinguish rheumatoid arthritis (RA) from osteoarthritis (OA) using hand radiographs and to evaluate the effects of changing pretraining and training parameters on model performance. MATERIALS AND METHODS: A convolutional neural network was retrospectively trained on 9714 hand radiograph exams from 8387 patients obtained from 2017 to 2021 at seven hospitals within an integrated healthcare network. Performance was assessed using an independent test set of 250 exams from 146 patients. Binary discriminatory capacity (no arthritis versus arthritis; RA versus not RA) and three-way classification (no arthritis versus OA versus RA) were evaluated. The effects of additional pretraining using musculoskeletal radiographs, using all views as opposed to only the posteroanterior view, and varying image resolution on model performance were also investigated. Area under the receiver operating characteristic curve (AUC) and Cohen's kappa coefficient were used to evaluate diagnostic performance. RESULTS: For no arthritis versus arthritis, the model achieved an AUC of 0.975 (95% CI: 0.957, 0.989). For RA versus not RA, the model achieved an AUC of 0.955 (95% CI: 0.919, 0.983). For three-way classification, the model achieved a kappa of 0.806 (95% CI: 0.742, 0.866) and accuracy of 87.2% (95% CI: 83.2%, 91.2%) on the test set. Increasing image resolution increased performance up to 1024 × 1024 pixels. Additional pretraining on musculoskeletal radiographs and using all views did not significantly affect performance. CONCLUSION: A deep learning model can be used to distinguish no arthritis, OA, and RA on hand radiographs with high performance.

Radiation dose of fluoroscopy-guided versus ultralow-dose CT-fluoroscopy-guided lumbar spine epidural steroid injections.

OBJECTIVE: Compare radiation dose of lumbar spine epidural steroid injections (ESIs) performed under fluoroscopy guidance and ultralow-dose CT-fluoroscopy guidance. MATERIALS AND METHODS: Retrospective review of consecutive lumbar ESIs performed using fluoroscopy, between May 2017 and April 2019, and using ultralow-dose CT-fluoroscopy, between August 2019 and February 2021, was performed. Ultralow-dose CT-fluoroscopy technique omits a planning CT scan, utilizes CT-fluoroscopy, and minimizes radiation dose parameters. Patient characteristics (age, sex, height, weight, body mass index (BMI)), procedural characteristics (anatomic level, type of ESI, procedure time, pain reduction, complications, trainee participation), and radiation dose were compared. Chi-square tests and two-sample t-tests were performed for statistical analysis. RESULTS: One hundred and forty-seven patients (mean age 55.8 ± 16.7; 85 women) underwent ESIs using fluoroscopy. Sixty-six patients (mean age 60.9 ± 16.7; 33 women) underwent ESIs using ultralow-dose CT-fluoroscopy. The effective dose for the fluoroscopy group was 0.30 mSv ± 0.34, compared to 0.15 mSV ± 0.11 for ultralow-dose CT-fluoroscopy (p < 0.001). The average age in the CT-fluoroscopy group was older (p = 0.04), and there was more trainee participation in the fluoroscopy group (p < 0.001); otherwise there was no statistically significant difference in patient or procedural characteristics between the conventional fluoroscopy group and the ultralow-dose CT-fluoroscopy group. There was no statistically significant difference in immediate post-procedure pain reduction between the groups (p = 0.16). Four intrathecal injections occurred only in the fluoroscopy group, though this difference was not significant (p = 0.18). CONCLUSION: Ultralow-dose CT-fluoroscopy technique for image-guided lumbar spine ESIs can lower radiation dose compared to fluoroscopy-guided technique.

Tibial bone stress injury: diagnostic performance and inter-reader agreement of an abbreviated 5-min magnetic resonance protocol.

OBJECTIVE: To compare the diagnostic performance and inter-reader agreement of an abbreviated (5 min) MR protocol compared to a complete (25 min) protocol, for evaluation of suspected tibial bone stress injury. MATERIALS AND METHODS: This IRB-approved retrospective study consisted of 95 consecutive MR examinations in 88 patients with suspected tibial bone stress injury. Three musculoskeletal radiologists independently classified all examinations utilizing both an abbreviated protocol consisting only of axial T2-weighted images with fat suppression, and after a washout period again classified the complete examinations. Accuracy was calculated as proportion of cases classified exactly, within 1 grade, within 2 grades, and also utilizing a simplified "clinically relevant" classification combining grades 2, 3, and 4A into a single group. Significance testing was performed with the chi-test, and a post-hoc power analysis was performed. Inter-reader agreement was calculated with Kendall's coefficient of concordance, with significance testing performed utilizing the z-test after bootstrapping to obtain the standard error. RESULTS AND CONCLUSIONS: There was no significant difference in accuracy of grading tibial bone stress injuries between complete and abbreviated examinations. For complete exams, pooled exact accuracy was 47.8%; accuracy within 1 grade was 82.8%; and accuracy within 2 grades was 96.1%. For the abbreviated protocol, corresponding accuracies were 50.2, 82.0, and 93.9%. With the "clinically relevant" simplified classification, accuracy was 58.6% for complete exams and 64.2% for abbreviated exams. There was no significant difference in inter-reader agreement, with substantial agreement demonstrated for both complete (Kendall coefficient of concordance 0.805) and abbreviated examinations (coefficient of 0.767).

Acute non-contact anterior cruciate ligament tears are associated with relatively increased vastus medialis to semimembranosus cross-sectional area ratio: a case-control retrospective MR study.

OBJECTIVE: Hamstring muscle deficiency is increasingly recognized as a risk factor for anterior cruciate ligament (ACL) tears. The purpose of this study is to evaluate the vastus medialis to semimembranosus cross-sectional area (VM:SM CSA) ratio on magnetic resonance imaging (MRI) in patients with ACL tears compared to controls. MATERIALS AND METHODS: One hundred knee MRIs of acute ACL tear patients and 100 age-, sex-, and side-matched controls were included. Mechanism of injury, contact versus non-contact, was determined for each ACL tear subject. The VM:SM CSA was measured on individual axial slices with a novel method using image-processing software. One reader measured all 200 knees and the second reader measured 50 knees at random to assess inter-reader variability. The intraclass correlation coefficient (ICC) was calculated to evaluate for correlation between readers. T-tests were performed to evaluate for differences in VM:SM CSA ratios between the ACL tear group and control group. RESULTS: The ICC for agreement between the two readers was 0.991 (95% confidence interval 0.984-0.995). Acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.44 vs. 1.28; p = 0.005). Non-contact acute ACL tear patients have an increased VM:SM CSA ratio compared to controls (1.48 vs. 1.20; p = 0.003), whereas contact acute ACL tear patients do not (1.23 vs. 1.26; p = 0.762). CONCLUSION: Acute non-contact ACL tears are associated with increased VM:SM CSA ratios, which may imply a relative deficiency in hamstring strength. This study also demonstrates a novel method of measuring the relative CSA of muscles on MRI.

Traumatic Finger Injuries: What the Orthopedic Surgeon Wants to Know.

Traumatic finger injuries account for a substantial number of emergency visits every year. Imaging plays an important role in diagnosis and in directing management of these injuries. Although many injuries can be managed conservatively, some require more invasive interventions to prevent complications and loss of function. Accurate diagnosis of finger injuries can often be difficult, given the complicated soft-tissue anatomy of the hand and the diverse spectrum of injuries that can occur. To best serve the patient and the treating physician, radiologists must have a working knowledge of finger anatomy, the wide array of injury patterns that can occur, the characteristic imaging findings of different finger injuries, and the most appropriate treatment options for each type of injury. This article details the intricate anatomy of the hand as it relates to common finger injuries, illustrates the imaging findings of a range of injuries, presents optimal imaging modalities and imaging parameters for the diagnosis of different injury types, and addresses which findings have important management implications for the patient and the orthopedic surgeon. With this fund of knowledge, radiologists will be able to recommend the most appropriate imaging studies, make accurate diagnoses, convey clinically relevant imaging findings to the referring physician, and suggest appropriate follow-up examinations. In this way, the radiologist will help improve patient care and outcomes. Online supplemental material is available for this article. (©)RSNA, 2016.

Standardized Classification of Lumbar Spine Degeneration on Magnetic Resonance Imaging Reduces Intra- and Inter-subspecialty Variability.

BACKGROUND AND PURPOSE: To determine the efficacy of standardized definitions of degenerative change in reducing variability in interpretation of lumbar spine magnetic resonance imaging within and between groups of subspecialty-trained neuroradiologists (NR) and musculoskeletal radiologists (MSK). MATERIALS AND METHODS: Six radiologists, three from both NR and MSK groups were trained on a standardized classification system of degenerative change. After an 11-month washout period, they independently re-interpreted fifty exams at the L4-L5 and L5-S1 levels. Responses were converted to a six-point ordinal scale for the assessment of neural foraminal stenosis and spinal canal stenosis (SCS), three-point scale for lateral recess stenosis, and four-point scale for facet osteoarthritis (FO). Intra-subspecialty and inter-subspecialty analysis was performed using the weighted Cohen's kappa with a binary matrix of all reader pairs. RESULTS: Inter-subspecialty agreement improved from k=0.527 (moderate) to k=0.602 (substantial) for neural foraminal stenosis, from k=0.540 (moderate) to k=0.652 (substantial) for SCS, from k=0.0818 (slight) to k=0.337 (fair) for lateral recess stenosis, and from k=0.176 (slight) to k=0.495 (moderate) for FO. The NR group demonstrated improved intra-subspecialty agreement for the assessment of SCS, from k=0.368 (fair) to k=0.638 (substantial). The MSK group demonstrated improved intra-subspecialty agreement for the assessment of FO, from k=0.134 (slight) to k=0.413 (moderate). Intra-subspecialty agreement was similar for other parameters before and after training. CONCLUSIONS: As result of the standardized definitions training, the NR and MSK groups each improved in one of the four parameters, while inter-subspecialty variability improved in all four parameters. These definitions may be useful in clinical practice across radiology subspecialties.

Intra- and Intersubspecialty Variability in Lumbar Spine MRI Interpretation: A Multireader Study Comparing Musculoskeletal Radiologists and Neuroradiologists.

BACKGROUND AND PURPOSE: The purpose of this study is to assess the differences in degenerative spine MRI reporting between subspecialty-trained attending neuroradiologists and musculoskeletal radiologists (MSK) at a single institution, academic medical center. MATERIALS AND METHODS: Fifty consecutive outpatient noncontrast lumbar spine examinations were selected from the Picture Archiving and Communication System. Three MSK and 3 neuroradiologists (NR) independently reviewed and interpreted the exams at the L4-L5 and L5-S1 levels in the same manner as in clinical practice. The assessment of neural foraminal stenosis (NFS) and spinal canal stenosis (SCS) was converted to a 5-point ordinal scale. The assessment of lateral recess stenosis (LRS) and facet osteoarthritis (FO) was recorded as present/absent. Intersubspecialty and intrasubspecialty analysis was performed using Cohen's kappa coefficient with a binary matrix of all reader pairs. RESULTS: There was moderate intersubspecialty agreement (k = 0.527) for NFS and SCS (k = 0.540). Intersubspecialty agreement was slight for LRS (k = 0.0818) and FO (k = 0.176). The MSK group demonstrated greater intrasubspecialty agreement in assessment of NFS and SCS compared to the NR group, with nonoverlapping confidence intervals. The NR group demonstrated greater nominal intrasubspecialty agreement in the assessment of both LRS and FO, although with nonoverlapping confidence intervals. CONCLUSION: There is moderate intersubspecialty agreement between MSK radiologists and neuroradiologists in reporting the severity of NFS and SCS, although MSK radiologists demonstrated greater intrasubspecialty agreement. There is slight intersubspecialty agreement for LRS and FO. The demonstration of differences in inter-reader agreement is a crucial first step to attempt to ameliorate these variabilities.