SLR - February 2021 - Steven L. Anderson
Reference: Falkowski AL, Jacobson JA, Freehill MT, Kalia V. Hand-Held Portable Versus Conventional Cart-Based Ultrasound in Musculoskeletal Imaging. Orthop J Sports Med. 2020 Feb 12;8(2)Level of Evidence: II
Scientific Literature Review
Reviewed By: Steven L. Anderson, DPM
Residency Program: Grant Medical Center – Columbus, OH
Podiatric Relevance: When compared to MRI, ultrasound has the advantage of dynamic images, fewer contraindications, and lower cost. In recent years, it is increasingly utilized in the assessment of musculoskeletal disorders. But several barriers prevent it from being used more universally among podiatric physicians. These barriers include the cost of equipment, lack of portability, and lack of training. The advent of hand-held ultrasound devices may help circumvent several of these barriers and allow more practitioners to utilize the ultrasound modality with patients. This article investigates the accuracy of hand-held devices in the diagnosis of musculoskeletal disorders.
Methods: One hundred patients were evaluated by a single fellowship-trained musculoskeletal radiologist. Patients were first evaluated with a hand-held device and then a cart-based device, both with a 12-5 MHz transducer. The resulting diagnoses were recorded and examined for agreement. If disagreement occurred, an orthopedic surgeon assisted in determining how the discrepancy would change the clinical management of the patient.
Results: There was concordance between the devices in 65 percent of patients. Of the 35 patients with discordant results, clinical management had no change in 16 patients, probably no change in 10 patients, uncertain change in five patients, probable change in four patients and definite change in zero patients. Overall, the results between the two devices were either concordant or discordant without clinical relevance in 96 percent of patients. The four patients with probable change to clinical management included the following: nondetection of a 2 millimeter satellite nodule associated with a superficial mass, incorrect interpretation of a 5 millimeter ganglion cyst as a possible solid mass, overlooked direct inguinal and femoral hernias, and misdiagnosis of partial gluteus medius tendon tear as tendinosis.
Conclusions: The authors concluded that there was high clinical correlation between hand-held and cart-based ultrasound. These results are reassuring given that this is the first study to evaluate the accuracy of hand-held ultrasound in diagnosing musculoskeletal disorders. But this study must be understood in context. First, the single observer was a fellowship-trained musculoskeletal radiologist with 23 years of experience. This level of ultrasound training is likely far superior to that of most podiatric physicians and ultrasound is said to be highly “operator dependent.” Second, the hand-held ultrasound is limited by its lack of power doppler and available transducers.
Only the color doppler was used in this study and resulted in only minor diagnostic discrepancies. With transducers, the hand-held is intrinsically limited to the linear 12-5 MHz, whereas the cart-based unit can accommodate higher frequency probes that provide greater resolution. The cart-based device was handicapped for the purpose of this study. Conventional ultrasound is superior in many ways, but cost can be prohibitive with units often greater than $100,000. Hand-held in contrast cost approximately $2,000-7,000. This staggering difference in cost combined with acceptable differences in diagnostic ability could redefine the prerequisites to wielding an ultrasound probe. For the foreseeable future, the superiority of cart-based ultrasound makes it the preferred device, but this study illustrates the utility of hand-held devices where conventional units are prohibitive.