Esther H. Y. Hung

Imaging of the anterior cruciate ligament

The anterior cruciate ligament (ACL) is an important structure in maintaining the normal biomechanics of the knee and is the most commonly injured knee ligament. However, the oblique course of the ACL within the intercondylar fossa limits the visualization and assessment of the pathology of the ligament. This pictorial essay provides a comprehensive and illustrative review of the anatomy and biomechanics as well as updated information on different modalities of radiological investigation of ACL, particularly magnetic resonance imaging.

Ultrasound of Musculoskeletal Soft-Tissue Tumors Superficial to the Investing Fascia

OBJECTIVE The objective of our study was to evaluate the diagnostic accuracy of ultrasound in assessing musculoskeletal soft-tissue tumors superficial to the investing fascia. MATERIALS AND METHODS Seven hundred fourteen superficial soft-tissue tumors evaluated with ultrasound by two musculoskeletal radiologists were retrospectively reviewed. In all ultrasound reports, the reporting radiologists provided one, two, or three diagnoses depending on their perceived level of diagnostic certainty. Two hundred forty-seven tumors had subsequent histologic correlation, thus allowing the accuracy of the ultrasound diagnosis to be determined. Images of the lesions with a discordant ultrasound diagnosis and histologic diagnosis were reviewed, and the ultrasound features were further classified as concordant with the known histologic diagnosis, concordant with the known histologic diagnosis with atypical features present, or discordant with the known histologic diagnosis. Four hundred sixty-seven tumors without pathologic confirmation were followed up clinically. RESULTS Overall the accuracy of ultrasound examination for assessing superficial soft-tissue masses was 79.0% when all differential diagnoses were considered and 77.0% when only the first differential diagnosis was considered. The sensitivity and specificity of the first ultrasound diagnosis were 95.2% and 94.3%, respectively, for lipoma; 73.0% and 97.7% for vascular malformation; 80.0% and 95.4% for epidermoid cyst; and 68.8% and 95.2% for nerve sheath tumor. Reduced observer awareness of specific tumor entities tended to contribute to underdiagnosis more than poor specificity of ultrasound findings. Most tumors (236/247, 96%) were benign. The sensitivity and specificity of ultrasound for identifying malignant superficial soft-tissue tumors was 94.1% and 99.7%, respectively. CONCLUSION The diagnostic accuracy of ultrasound in the assessment of superficial musculoskeletal soft-tissue tumors is high and can be improved through increased radiologist awareness of less frequently encountered tumors. Ultrasound is accurate for differentiating benign from malignant superficial soft-tissue tumors.

Performance of Interferon-gamma Release Assay for Tuberculosis Screening in Inflammatory Bowel Disease Patients

Background:Screening for latent tuberculosis (TB) is mandatory in inflammatory bowel disease (IBD) before starting anti–tumor necrosis factor therapy. Data on the utility of screening tests in populations with moderate background risk of TB are limited. This study aims to evaluate the performance of interferon-gamma release assay (IGRA) with QuantiFERON-TB Gold in IBD patients in a TB endemic region. Methods:Two hundred sixty-eight consecutive adult IBD patients and 234 healthy controls were prospectively recruited. Detailed clinical history, chest x-ray findings, and IGRA results were documented for all individuals. The IGRA positive rates between IBD patients, with or without immunosuppressant, and healthy controls were compared. Results:The IGRA result was positive in 21.9% of IBD patients and 19.2% of healthy controls (P = 0.535). IBD patients on immunosuppressive therapy had a significantly lower IGRA positive rate (13.0% versus 29.6%; P = 0.002) compared with immunosuppressant-naive IBD patients. This difference seemed to be most prominent for patients taking azathioprine (11.8% versus 27.3%, P = 0.006). Conclusions:IGRA results are negatively impacted by immunosuppressive therapy. Current guidelines suggesting TB screening before anti–tumor necrosis factor therapy may be inadequate in patients already on immunosuppressive drugs. Latent TB testing seems best performed before the initiation of immunosuppressive therapies in IBD patients.

Comparison of ultrasound versus fluorcoscopic guided rotator cuff interval approach for MR arthrography

Our purpose is to compare ultrasound and fluoroscopic-guided approaches to the glenohumeral joint at the rotator cuff interval for magnetic resonance (MR) arthrography of the shoulder. Forty consecutive patients were prospectively studied. 20 patients underwent ultrasound-guided and 20 patients underwent fluoroscopic guided injection. Successful rate of ultrasound guidance is 95%. No significant difference in pain score and duration of injection between two methods (P>.05). Ultrasound-guided rotator cuff interval injection of the glenohumeral joint for MR arthrography is comparable with fluoroscopic-guided injection. Ultrasound is the preferred method as there is no ionizing radiation.

Diagnostic capability of low- versus high-field magnetic resonance imaging for lumbar degenerative disease.

Study Design. Cohort study. Objective. To investigate the diagnostic capability of low-field magnetic resonance imaging (MRI) compared with high-field MRI for degenerative disease of the lumbar spine. Summary of Background Data. Low-field MRI has several advantages over high-field magnetic resonance systems (easier installation, lower purchase, and maintenance cost). The diagnostic capability of low-field MRI for degenerative disease of the lumbar spine has not been compared with that of high-field MRI. Methods. Hundred patients (mean age: 56.3 yr, range: 32–80; F:M = 59:41) with neurogenic claudication or sciatica were studied. All patients underwent MRI of the lumbar spine on both low-field (0.25T) and high-field (1.5T or 3.0T) magnetic resonance systems. Intervertebral disc herniation, central canal, lateral recess, and exit foraminal stenosis as well as nerve root compression at L3–L4, L4–L5, and L5–S1 were evaluated by 2 radiologists for both low- and high-field systems using established reliable grading systems. Results. There was excellent agreement between low- and high- field MRI with regard to grading the presence and severity of disc herniation (r = 0.92–0.94; P < 0.05), central canal stenosis (r = 0.89–0.91; P < 0.05), lateral recess stenosis (r = 0.81–0.87; P < 0.05), and exit foramen stenosis (r = 0.81–0.89; P < 0.05). Descending or exiting nerve root compression occurred in 52% of patients at L3–L4, L4–L5, or L5–S1 levels, with good agreement between low-field and high-field MRI (r = 0.71–0.76; P < 0.05) for nerve root compression. Conclusion. Excellent reliability between low- and high- field MRI was found for most features of lumbar disc degeneration, with good agreement for nerve root compression. 0.25T MRI was more susceptible to motion artifact, probably due to longer scanning time. Level of Evidence: 3

Angioplasty and stenting for intracranial atherosclerotic stenosis with nitinol stent: factors affecting technical success and patient safety.

BACKGROUND: Angioplasty and stenting using nitinol stents is a recognized treatment option for intracranial atherosclerosis. OBJECTIVE: To identify procedure-related factors that may affect patient safety and technical outcome. METHODS: In this prospective study of 57 consecutive patients, the primary end points were intraprocedural technical problems, periprocedure morbidity, and complications. Major periprocedure complication was defined as all stroke or death at 30 days. Technical failure was defined as the inability to complete the procedure because of technical or safety problems. Procedure failure was defined as a procedure outcome of technical failure or major periprocedure complication. Secondary end points were procedure-related factors that may affect patient safety and technical outcome. RESULTS: Procedure failure rate was 12.3% (7/57) (major periprocedure complication rate, 5.3% [3/57]; technical failure rate, 7% [4/57]). Initial failure in tracking of balloon or stent occurred in 20 patients, other technical problems occurred in 11 patients, including kinking or trapping of balloon catheter (2 cases), difficulty in unsheathing of stent (3 cases), forward migration of stent during deployment (4 cases), trapping of nose cone after stent deployment (1 case), fracture of delivery system (2 cases), and guidewire fracture (1 case). Unfavorable vascular morphology signified by the presence of 2 or more reverse curves along the access path was found to associate with initial failure in the tracking of instruments (OR = ∞), and occurrence of other technical problems (OR = 25). CONCLUSION: Procedure-related factors could be identified and lead to improvements in patient safety and technical outcome. Tortuous vascular morphology is a key factor to be overcome.

Can MRI predict the clinical instability and loss of the screw home phenomenon following ACL tear

Our purpose was to determine the relationship between tibiofemoral translation on magnetic resonance imaging and clinical instability of the knee following anterior cruciate ligament (ACL) injury. Within 66 patients (43 males, 23 females, mean age 30.25 years), 15 of 19 patients (80%) with an intact ACL had a demonstrable normal screw home movement, while 24 of 47 patients (51%) with an ACL tear had absence of the screw home movement. Patients with clinical instability had greater tibial translation and excursion at the lateral compartment (P=.0001). Following ACL injury, there is demonstrable absence of the normal screw-home movement with anterior tibial translation and excursion related to presence of clinical instability.

Case-Control Study of Intra-arterial Verapamil for Intraprostatic Anastomoses to Extraprostatic Arteries in Prostatic Artery Embolization for Benign Prostatic Hypertrophy.

PURPOSE It is hypothesized that intra-arterial administration of verapamil is a safe and effective way to reverse the flow in intraprostatic anastomoses to extraprostatic arteries without compromising treatment outcomes in prostatic artery embolization (PAE) for benign prostatic hypertrophy (BPH). MATERIALS AND METHODS A prospective study of 62 prostate sides in 31 consecutive patients (median age, 66 y; range, 60-71 y) with symptomatic BPH was undertaken. Median prostate volume was 72.4 mL (range, 48.8-85.8 mL), median International Prostate Symptom Score was 21 (range, 15-23), and median urine peak flow rate was 4 mL/s (range, 2-6 mL/s). The arterial anastomoses were classified as types I-III according to vascular morphology. Treatment safety was assessed in terms of adverse events and complications, and treatment effectiveness was assessed in terms of success rate of angiographic flow reversal. RESULTS The PAE procedure was successfully completed in all 31 patients (100%). Adverse events in both groups were transient and mild and did not necessitate prolonged hospitalization. There was no clinical evidence of any significant nontarget ischemic complication in either group. Intraprostatic anastomosis was diagnosed in 19 of 31 patients (61.3%) and 22 of 62 prostate sides (35.5%). Success rates of verapamil treatment were 88.9% overall (20 of 22) and 100% (19 of 19) in type II and III anastomoses. There was no difference between the treatment group and the control group in clinical, urologic, and imaging outcomes of PAE. CONCLUSIONS Intra-arterial verapamil treatment was probably safe and effective in causing flow reversal in type II and III intraprostatic anastomoses and in preventing ischemic complications in PAE for BPH without compromising PAE outcomes.

Reply to "accuracy of ultrasound of musculoskeletal soft-tissue tumors".

AJR 2015; 204:W219 0361–803X/15/2042–W219

Reply to "Ultrasound Accuracy in the Diagnosis of Skin and Soft-Tissue Lesions"

AJR 2015; 204:W221 0361–803X/15/2042–W221