Imaging Insights Into Abdominal Wall Function.

Purpose: The successful repair of any complex ventral hernia requires a thorough understanding of the underlying anatomical defect and its functional context. We describe an improved "functional" approach to CT imaging of the abdominal wall that can facilitate this understanding and assist surgical planning. Methods: This invited article reports the observational experience gained from the functional abdominal wall CT examinations of 88 patients who underwent complex ventral hernia repair using pre-operative Botulinum toxin A (BTA) infiltration of the lateral oblique abdominal muscles as well as a further eight patients with diastasis rectus abdominis who were examined to exclude ventral hernia. Results: The use of a functional CT protocol which supplements resting images with additional "crunching" images (acquired with the abdominal wall muscles all strongly contracted) can significantly improve the demonstration of ventral hernia defects. Crunching acquisitions can also help differentiate true hernias from dysfunctional bulges, identify muscle denervation or atrophic changes, reveal otherwise occult hernias that may be missed on resting or Valsalva images alone, and assist the pre-operative assessment of BTA effect. Conclusion: A more functional approach to pre-operative CT imaging of the abdominal wall can significantly improve the understanding of complex ventral hernia defects and help formulate effective surgical plans that achieve low recurrence rates and good functional outcomes.

Preoperative Progressive Pneumoperitoneum Revisited.

Incisional hernia represents a common and potentially serious complication of open abdominal surgery, with up to 20% of all patients undergoing laparotomy subsequently developing an incisional hernia. This incidence increases to as much as 35% for laparotomies performed in high-risk patients and emergency procedures. A rarely used technique for enabling closure of large ventral hernias with loss of domain is preoperative progressive pneumoperitoneum (PPP), which uses intermittent insufflation to gradually stretch the contracted abdominal wall muscles, increasing the capacity of the abdominal cavity and allowing viscera to re-establish right of domain. This assists in tension-free closure of giant hernias which may otherwise be considered inoperable. This technique may be used on its own, or in conjunction with preoperative Botulinum Toxin A to confer paralysis to the lateral oblique muscles. These two complementary techniques, are changing the way complex hernias are managed.

What Is the Most Reliable Method of Measuring Glenoid Bone Loss in Anterior Glenohumeral Instability? A Cadaveric Study Comparing Different Measurement Techniques for Glenoid Bone Loss.

BACKGROUND: Preoperative quantification of bone loss has a significant effect on surgical decision making and patient outcomes. Various measurement techniques for calculating glenoid bone loss have been proposed in the literature. To date, no studies have directly compared measurement techniques to determine which technique, if any, is the most reliable. PURPOSE/HYPOTHESIS: To identify the most consistent and accurate techniques for measuring glenoid bone loss in anterior glenohumeral instability. Our hypothesis was that linear measurement techniques would have lower consistency and accuracy than surface area and statistical shape model-based measurement techniques. STUDY DESIGN: Controlled laboratory study. METHODS: In 6 fresh-frozen human shoulders, 3 incremental bone defects were sequentially created resulting in a total of 18 glenoid bone defect samples. Analysis was conducted using 2D and 3D computed tomography (CT) en face images. A total of 6 observers (3 experienced and 3 with less experience) measured the bone defect of all samples with Horos imaging software using 5 common methods. The methods included 2 linear techniques (Shaha, Griffith), 2 surface techniques (Barchilon, PICO), and 1 statistical shape model formula (Giles). Intraclass correlation (ICC) using a consistency model was used to determine consistency between observers for each of the measurement methods. Paired t tests were used to calculate the accuracy of each measurement technique relative to physical measurement. RESULTS: For the more experienced observers, all methods indicated good consistency (ICC > 0.75; range, 0.75-0.88), except the Shaha method, which indicated moderate consistency (0.65 < ICC < 0.75; range, 0.65-0.74). Estimated consistency among the experienced observers was better for 2D than 3D images, although the differences were not significant (intervals contained 0). For less experienced observers, the Giles method in 2D had the highest estimated consistency (ICC, 0.88; 95% CI, 0.76-0.95), although Giles, Barchilon, Griffith, and PICO methods were not statistically different. Among less experienced observers, the 2D images using Barchilon and Giles methods had significantly higher consistency than the 3D images. Regarding accuracy, most of the methods statistically overestimated the actual physical measurements by a small amount (mean within 5%). The smallest bias was observed for the 2D Barchilon measurements, and the largest differences were observed for Giles and Griffith methods for both observer types. CONCLUSION: Glenoid bone loss calculation presents variability depending on the measurement technique, with different consistencies and accuracies. We recommend use of the Barchilon method by surgeons who frequently measure glenoid bone loss, because this method presents the best combined consistency and accuracy. However, for surgeons who measure glenoid bone loss occasionally, the most consistent method is the Giles method, although an adjustment for the overestimation bias may be required. CLINICAL RELEVANCE: The Barchilon method for measuring bone loss has the best combined consistency and accuracy for surgeons who frequently measure bone loss.

Functional 3DVR imaging of abdominal wall hernias.

The purpose of this illustrative pictorial series is to demonstrate the value of an image technique known as 3D Volume Rendering (3DVR) for the pre-operative visualization and assessment of complex abdominal hernias. A small subset of complex abdominal hernia cases were selected from our early clinical experience with 3DVR to illustrate the value of visualizing standard 2D computed tomography (CT) data from a 3D perspective. For the surgeon, pre-operative 3DVR can assist the holistic understanding of abdominal hernias and any associated fascial defects, unsuspected additional hernias, dysfunctional abdominal wall bulges/eventrations, muscle denervations or atrophic changes, mesh placements, other post-surgical changes such as scarring, and relevant skeletal changes. For the patient, 3DVR provides an easily grasped understanding of the relevant anatomy, the nature of the problem at hand, and the scale of the surgical challenge. Images of this kind can help the surgeon to more effectively manage unrealistic patient expectations or explain dysfunctional bulges that do not require surgery. A functional 3DVR approach to pre-operative imaging can provide the surgeon with a more complete understanding of any hernia defect and the relevant background status of the abdominal wall in general. This can be useful in planning a more effective operative approach and help to improve surgical outcomes.

Does proximal porous coating in short-stem humeral arthroplasty reduce stress shielding?

CONTEXT: Short-stem humeral designs in shoulder arthroplasty have been introduced recently. A retrospective cohort study was conducted to determine if newer proximal porous titanium coating in humeral short stems produced clinical and radiologic improvements. METHOD: Short-stem humeral implants (Tornier Ascend, Wright Medical) were used in 46 anatomical total shoulder replacements from October 2012 to December 2015. Clinical and radiologic measures were analyzed at one- and two-year follow-up. RESULTS: Nineteen shoulders received earlier grit blasted stems (Ascend Monolithic), and 27 shoulders received the later stems with proximal titanium porous coating (Ascend Flex). At two-year follow-up, radiographic changes and stress shielding were similar. Medial cortical thinning were more frequently observed in Monolithic (18 of 19) compared to Flex stems (19 of 27) on the PA films, though this was not statistically significant (P = 0.061). Clinical outcome scores improved regardless of the stem type used and independent of the radiologic adaptations on plain films. One participant with the Ascend Flex developed glenoid component failure and rotator cuff tear and was subsequently revised. DISCUSSION: Clinical and radiological outcomes are similar in both short-stem designs. Proximal titanium porous coating may reduce medial calcar cortical thinning but it does not prevent it. KEY MESSAGE: When compared to similarly designed uncoated grit-blasted stems, proximally porous coated humeral short stems produced similar clinical and radiological results. The proximal titanium porous coating may reduce medial cortical thinning.

Limitations of Electromyography in the Assessment of Abdominal Wall Muscle Contractility Following Botulinum Toxin A Injection.

Purpose: Pre-operative botulinum toxin A (BTA) injection of the lateral obliques aims to facilitate the closure of large ventral hernia defects and decrease the risk of repair breakdown during the critical healing phase. The exact duration of post-operative BTA effect and top-up timing in cases at high risk of recurrence remains uncertain. This study was designed to assess the value of electromyography (EMG) in determining the appropriate time for BTA top-up. Methods: 56 patients underwent ventral hernia repair with pre-operative BTA infiltration of the lateral obliques. Eleven patients at high risk of recurrence considered suitable for BTA top-up were assessed post-operatively with both functional computed tomography (CT) and EMG. CT assessed segmental contractility of each muscle layer. Single-point EMG assessed the activity of individual muscle layers bilaterally in the anterior axillary line. Results: CT showed (i) variable contractility of anterior and posterior muscle segments prior to BTA injection; (ii) absent or incomplete muscle paralysis in over half of all segments; (iii) increased BTA effect on progress scans; and (iv) non-uniform pattern of change in BTA effect between the anterior and posterior muscle. EMG demonstrated modest voluntary activity in most muscle layers. Compared to standard of reference (CT), EMG showed moderate sensitivity (0.62), poor specificity (0.48), poor accuracy (0.57), and incorrect grading in 71% of true positive results. Conclusions: As BTA effect wanes, single-point EMG cannot reliably determine functional muscle status. A novel finding is that BTA-induced paralysis of the abdominal muscles may be remarkably non-uniform in degree, distribution and duration.

Preoperative Botulinum toxin A enabling defect closure and laparoscopic repair of complex ventral hernia.

INTRODUCTION: Operative management of complex ventral hernia still remains a significant challenge for surgeons. Closure of large defects in the unprepared abdomen has serious pathophysiological consequences due to chronic contraction and retraction of the lateral abdominal wall muscles. We report outcomes of 56 consecutive patients who had preoperative Botulinum toxin A (BTA) abdominal wall relaxation facilitating closure and repair. METHODS: This was a prospective observational study of 56 patients who underwent ultrasound-guided BTA into the lateral abdominal oblique muscles prior to elective ventral hernia repair between November 2012 and January 2017. Serial non-contrast abdominal CT imaging was performed to evaluate changes in lateral oblique muscle length and thickness. All hernias were repaired laparoscopically, or laparoscopic-open-laparoscopic (LOL) using intraperitoneal onlay mesh. RESULTS: 56 patients received BTA injections at predetermined sites to the lateral oblique muscles, which were well tolerated. Mean patient age was 59.7 years, and mean BMI was 30.9 kg/m2 (range 21.8-54.0). Maximum defect size was 24 × 27 cm. A subset of 18 patients underwent preoperative pneumoperitoneum as an adjunct procedure. A comparison of pre-BTA to post-BTA imaging demonstrated an increase in mean lateral abdominal wall length from 16.1 cm to 20.1 cm per side, a mean gain of 4.0 cm/side (range 1.0-11.7 cm/side) (p < 0.0001). This corresponds to an unstretched mean length gain of 8.0 cm of the lateral abdominal wall. Laparoscopic/LOL primary closure was achieved in all cases, with no clinical evidence of raised intra-abdominal pressures. One patient presented with a new fascial defect 26 months post-operative. CONCLUSION: Preoperative BTA to the lateral abdominal wall muscles is a safe and effective technique for the preparation of patients prior to operative management of complex ventral hernias. BTA temporary flaccid paralysis relaxes, elongates and thins the chronically contracted abdominal musculature. This in turn reduces lateral traction forces facilitating laparoscopic repair and fascial closure of large defects under minimal tension.

Single port component separation: endoscopic external oblique release for complex ventral hernia repair.

BACKGROUND: Component separation (CS) is a technique which mobilizes flaps of innervated, vascularized tissue, enabling closure of large ventral hernia defects using autologous tissue. Disadvantages include extensive tissue dissection when creating these myofascial advancement flaps, with potential consequences of significant post-operative skin and wound complications. This study examines the benefit of a novel, ultra-minimally invasive single port anterior CS technique. METHODS: This was a prospective study of 16 external oblique (EO) releases performed in 9 patients and 4 releases performed in 3 fresh frozen cadavers. All patients presented with recurrent complex ventral hernias, and were administered preoperative Botulinum Toxin A to their lateral oblique muscles to facilitate defect closure. At the time of elective laparoscopic repair, patients underwent single port endoscopic EO release using a single 20-mm incision on each side of the abdomen. Measurements were taken using real-time ultrasound. Postoperatively, patients underwent serial examination and abdominal CT assessment. RESULTS: Single port endoscopic EO release achieved a maximum of 50-mm myofascial advancement per side (measured at the umbilicus). No complications involving wound infection, hematoma, or laxity/bulge have been noted. All patients proceeded to laparoscopic or laparoscopic-open-laparoscopic intraperitoneal mesh repair of their hernia, with no hernia recurrences to date. CONCLUSIONS: Single port endoscopic EO release holds potential as an adjunct in the repair of large ventral hernia defects. It is easy to perform, is safe and efficient, and entails minimal disruption of tissue planes and preserves abdominal wall perforating vessels. It requires only one port-sized incision on each side of the abdomen, thus minimizing potential for complications. Further detailed quantification of advancement gains and morbidity from this technique is warranted, both with and without prior administration of Botulinum Toxin A to facilitate closure.

Preoperative chemical component relaxation using Botulinum toxin A: enabling laparoscopic repair of complex ventral hernia.

BACKGROUND: Repair of complex ventral hernia can be very challenging for surgeons. Closure of large defects can have serious pathophysiological consequences. Botulinum toxin A (BTA) has recently been described to provide flaccid paralysis to abdominal muscles prior to surgery, facilitating closure and repair. METHODS: This was a prospective observational study of 32 patients who underwent ultrasound-guided injections of BTA to the lateral abdominal wall muscles prior to elective repair of complex ventral hernia between January 2013 and December 2015. Serial non-contrast abdominal CT imaging was performed to measure changes in fascial defect size, abdominal wall muscle length and thickness. All hernias were repaired laparoscopically or laparoscopic-assisted with placement of intra-peritoneal mesh. RESULTS: Thirty-two patients received BTA injections which were well tolerated with no complications. A comparison of baseline (preBTA) CT imaging with postBTA imaging demonstrated an increase in mean baseline abdominal wall length from 16.4 to 20.4 cm per side (p < 0.0001), which translates to a gain in mean transverse length of the unstretched anterolateral abdominal wall muscles of 4.0 cm/side (range 0-11.7 cm/side). Fascial closure was achieved in all cases, with no instances of raised intra-abdominal pressures or its sequelae, and there have been no hernia recurrences to date. CONCLUSIONS: Preoperative BTA injection to the muscles of the anterolateral abdominal wall is a safe and effective technique for the preoperative preparation of patients prior to laparoscopic mesh repair of complex ventral hernia. This technique elongates and thins the contracted and retracted musculature, enabling closure of large defects.

Preoperative progressive pneumoperitoneum complementing chemical component relaxation in complex ventral hernia repair.

BACKGROUND: A rarely used technique for enabling closure of large ventral hernias with loss of domain is preoperative progressive pneumoperitoneum (PPP), which uses intermittent insufflation to gradually stretch the contracted abdominal wall muscles, increasing the capacity of the abdominal cavity. This allows the re-introduction of herniated viscera into the abdominal cavity and assists in closure of giant hernias which may otherwise be considered inoperable. METHODS: This was a prospective study assessing 16 patients between 2013 and 2015 with multi-recurrent ventral hernia. All patients were treated preoperatively with both Botulinum Toxin A (BTA) injections to the lateral abdominal wall muscles to confer flaccid paralysis, and short-term PPP to passively expand the abdominal cavity. All patients underwent serial abdominal CT imaging, with pre- and post-treatment circumference measurements of the peritoneal cavity and hernia sac, prior to undergoing operative mesh repair of their hernia. RESULTS: The mean hernia defect size was 236 cm2, with mean 28 % loss of domain. The mean overall duration of PPP was 6.2 days. The mean gain in abdominal circumference was 4.9 cm (5.6 %) (p 0.002) after BTA and PPP. Fascial closure and mesh hernia repair were performed in all 16 patients, with no patients suffering from postoperative abdominal hypertension, ventilatory impairment, or wound dehiscence. There are no hernia recurrences to date. Eight patients (50 %) experienced PPP-related complications, consisting of subcutaneous emphysema, pneumothorax, pneumomediastinum, pneumocardium, and metabolic acidosis. No complication required intervention. CONCLUSIONS: PPP is a useful adjunct in the repair of complex ventral hernia. It passively expands the abdominal cavity, allowing viscera to re-establish right of domain. At the same time, it helps to minimize the risks of postoperative abdominal compartment syndrome and the sequelae of fascial closure under tension. However, its benefits must be carefully weighed with the risk of serious complications, such as infection, perforation, pneumothorax, and pneumomediastinum.

Preoperative abdominal muscle elongation with botulinum toxin A for complex incisional ventral hernia repair.

BACKGROUND: Surgical repair of recurrent abdominal incisional hernia(s) can be challenging due to complex operative conditions, intense post-operative pain, potential respiratory compromise and lateral muscle traction predisposing to early recurrence. We report our preliminary results with botulinum toxin A (BTA) injection causing flaccid paralysis (relaxation) of the lateral abdominal wall muscles prior to surgery. METHODS: A prospective pilot study measured the effect of preoperative BTA prior to elective repair of recurrent abdominal hernias. Under ultrasound control, 2 weeks prior to surgery, 50 units of BTA was injected into the external oblique, internal oblique and transversus abdominis muscles at three sites on each side of the lateral abdominal wall (total dose 300 units). Pre- and post-BTA abdominal computed tomography measured changes in abdominal wall muscle thickness and length. All hernias were repaired with laparoscopic or laparoscopic-assisted mesh techniques in a single or two-staged procedure. RESULTS: Eight patients received BTA injections which were tolerated with no complications. Post-BTA preoperative computed tomography showed a significant increase in mean length of lateral abdominal wall from 18.5 cm pre-BTA to 21.3 cm post-BTA (P = 0.017) with a mean unstretched length gain of 2.8 cm per side (range 0.8-6.0 cm). All hernias were surgically reduced with mesh with no early recurrence. CONCLUSION: Preoperative BTA injection prior to complex abdominal hernia repair is a safe procedure that causes flaccid relaxation, elongation and thinning of the lateral abdominal muscles and decrease in hernia defect. Although further evaluation is required, BTA injections may be a useful adjunct to surgical repair of complex incisional hernias.

Pubic apophysitis: a previously undescribed clinical entity of groin pain in athletes.

BACKGROUND: Sport-related pubalgia is often a diagnostic challenge in elite athletes. While scientific attention has focused on adults, there is little data on adolescents. Cadaveric and imaging studies identify a secondary ossification centre located along the anteromedial corner of pubis beneath the insertions of symphysial joint capsule and adductor longus tendon. Little is known about this apophysis and its response to chronic stress. AIM: We report pubic apophysitis as a clinically relevant entity in adolescent athletes. METHODS: The clinical and imaging findings in 26 highly trained adolescent football players (15.6 years ± 1.3) who complained of adductor-related groin pain were reviewed. The imaging features (X-ray 26/26, US 9/26, MRI 11/26, CT 7/26) of the pubic apophyses in this symptomatic group were compared against those of a comparison group of 31 male patients (age range 9-30 years) with no known history of groin pain or pelvic trauma, who underwent pelvic CT scans for unrelated medical reasons. RESULTS: All symptomatic subjects presented with similar history and physical findings. The CT scans of these patients demonstrated open pubic apophyses with stress-related physeal changes (widening, asymmetry and small rounded cyst-like expansions) that were not observed in the comparison group. No comparison subject demonstrated apophyseal maturity before 21 years of age, and immaturity was seen up to the age of 26 years. CONCLUSIONS: This retrospective case series identifies pubic apophyseal stress (or 'apophysitis') as an important differential consideration in the adolescent athlete who presents with groin pain.

Phalangeal microgeodic disease: report of two cases and review of imaging.

Phalangeal microgeodic disease is a rare disease that is frequently (though not invariably) related to cold exposure. In most cases, the clinical and radiographic findings of phalangeal microgeodic disease are sufficient to reach the diagnosis. The magnetic resonance imaging (MRI) findings of phalangeal microgeodic disease have been described in four cases in the English literature with two additional cases presented here. MRI allows a greater appreciation of affected bone areas and adds specificity to radiography with regard to diagnosis. In this sense, MRI is a helpful investigation in those cases of phalangeal microgeodic disease when doubt still exists following clinical and radiographic assessment.

Does anterior cruciate ligament reconstruction lead to degenerative disease?: Thirteen-year results after bone-patellar tendon-bone autograft.

BACKGROUND: Reporting of long-term outcome of anterior cruciate ligament (ACL) reconstruction with the patellar tendon (bone-patellar tendon-bone [BTB]) autograft is limited. There are concerns that degenerative joint disease is common in the long term, which may be associated with the procedure itself. HYPOTHESES: (1) ACL reconstruction with BTB provides good long-term outcome. (2) There are additional factors to surgical reconstruction that can be associated with the development of degenerative disease. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Of 161 patients, 114 were eligible. Patient-centered outcome was by Lysholm and subjective International Knee Documentation Committee (IKDC) score; objective outcome measures were clinical examination and IKDC radiological grade. RESULTS: Mean average follow-up was 13 years. The IKDC radiological grades in the worst compartment were A = 15%, B = 51%, C = 19%, and D = 14% (n = 83). There was a significant difference between the injured versus contralateral uninjured knee (n = 42, P = .003). In a subgroup with no meniscal or chondral injury the IKDC grades were A = 38%, B = 55%, C = 7%, and D = 0% (n = 29). The mean subjective scores were 89 ± 11 (Lysholm) and 83 ± 15 (IKDC) (n = 114). Poor IKDC subjective outcome was associated with chondral injury (P = .001), previous surgery (P = .022), return to sport (P = .013), and poor radiological grade in the ipsilateral medial compartment (P = .004). A poor IKDC radiological grade was associated with chondral injury (P = .002), meniscal injury (P = .010) and meniscectomy (P = .012), an IKDC subjective score of <85 (P = .01), and poor radiological grade in the contralateral medial compartment (P = .041). CONCLUSION: At 13 years, BTB ACL reconstruction provides a good outcome. Chondral and meniscal damage at surgery were associated with a poor radiological outcome, indicating that injuries sustained during ACL rupture may be the main predictors of degenerative bone disease.

Imaging of ankle tendinopathy and tears.

The major muscular prime movers and stabilizers of the foot and ankle originate in the mid to lower leg and send their tendons distally. Most of these tendons, with the exception of the Achilles and plantaris tendons, must negotiate a sharply curved course at the ankle and are stabilized by fibro-osseous tunnels, pulleys, or fibrous retinaculi before eventually inserting at the foot. Knowledge of specific tendon anatomy, contact points and sites of physical and vascular stress, helps to identify those regions susceptible to degeneration or tearing and to optimize the design of imaging protocols. This review covers the imaging modalities used to assess tendons about the ankle and issues related to their usage, normal tendon structure and relevant anatomy, normal imaging appearances and artifacts, and the common degenerative pathological processes which imaging can show.

Effectiveness of ultrasound-guided corticosteroid injection in the treatment of Morton's neuroma.

BACKGROUND: The purpose of this study was to evaluate the efficacy of corticosteroid injection and determine the duration of symptom-free period after treatment with a single ultrasound-guided injection for a painful Morton's neuroma. MATERIALS AND METHODS: From May 2002 to November 2003, 35 consecutive patients (7 males, 28 females) (mean age, 54; age range, 29 to 77 years) underwent a single ultrasound guided corticosteroid injection. Thirty-nine injections were performed as 4 patients had bilateral Morton's neuromas. The injection of 1.0 cc Celestone Chronodose (5.7 mg/ml) with 0.5 cc of 1% lidocaine was performed into the symptomatic intermetatarsal web-space. The efficacy of the injection was determined by the Johnson grading scale, and modified lower extremity functional scale. RESULTS: On the Johnson scale, 15 of 39 (38%) neuromas showed complete satisfaction 9 months after treatment and 11 of 39 (28%) were satisfied with minor reservations. A total of 26 of 39 (66%) neuromas had a positive outcome 9 months after the injection. On the functional daily activity (FDA) scale, 20 of 39 (51%) neuromas showed no difficulty and 4 of 39 (10%) indicated minor difficulties, which was considered a positive outcome 9 months after injection. Complete pain relief was achieved in 11 of 39 (28%) neuromas 9 months after treatment. Twelve of 39 (31%) neuromas did not respond to conservative treatment and required surgery. The results of treatment suggested improvement in efficacy if injection was used early. The size of the lesion measured on ultrasound showed no correlation with pain relief after injection. CONCLUSION: A single corticosteroid injection can offer short-term pain relief in the conservative management of Morton's neuroma.

The use of diagnostic imaging in sports medicine.

Imaging should only be undertaken if it is likely to influence patient management. The dose of ionising radiation to the patient should be considered. Requesting the appropriate imaging method requires an understanding of the pathological process. Plain x-ray should still generally be the first imaging technique; exceptions include some forms of superficial tendinopathy, in which ultrasound may be more appropriate, and situations where radiation exposure is contraindicated, such as in a pregnant patient. The cost of the examination to the patient and the community should also be considered (eg, ultrasound v magnetic resonance imaging).