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Biomedical subjects

J A Jacobson

Publications and source records attributed to J A Jacobson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Sonography and MR imaging of bifid median nerve with anatomic and histologic correlation.

OBJECTIVE: Imaging of a bifid median nerve has not been previously described in the radiology literature. We present three cases of bifid median nerve. The first is a patient with carpal tunnel syndrome seen on sonography and confirmed at surgery. The other two were found among 10 cadaveric specimens and were imaged with sonography and MR imaging. Confirmation of bifid median nerve in these two specimens was obtained using anatomic and histologic correlation. CONCLUSION: Sonography and MR imaging can allow effective diagnosis and delineation of a bifid median nerve in the wrist. This diagnosis is important to make before carpal tunnel release or other wrist surgeries are performed to avoid nerve injury. Furthermore, the sonographic size criteria for diagnosing carpal tunnel syndrome in nonbifid median nerves may not be accurate in evaluating bifid median nerves.

Adolescent↗
PubMed1999

Musculoskeletal sonography and MR imaging. A role for both imaging methods.

Sonography is currently being applied to many areas of the musculoskeletal system. Although some areas are in the experimental stage, there exist several indications in which sonography can produce results at least equal to what is possible with MR imaging. Examples include evaluation for shoulder and ankle tendon abnormalities; soft tissue infection and joint effusion; soft tissue foreign bodies; soft tissue masses, such as Baker's cyst and wrist ganglion cyst; carpal tunnel syndrome; developmental dysplasia of the hip; and other indications where MR imaging is contraindicated. The role of sonography in evaluation of the musculoskeletal system is evolving. With continued experience and research, newer applications for musculoskeletal sonography will likely become established further defining the roles of sonography and MR imaging in evaluation of the musculoskeletal system.

Achilles Tendon↗
PubMed1999

Ultrasound of fracture and bone healing.

This article reviews the ultrasound appearance of common fractures that may mimic other pathologies. Recent works suggest a role for ultrasound in the assessment of callus formation in delayed union of fractures and following the Ilizarov reconstructive procedures.

Bone and Bones↗
PubMed1999

May I take your order: a user-friendly resuscitation status and medical treatment plan form.

Practice did not conform with our hospital's Do Not Resuscitate (DNR) policy. We sought explanations and suggestions from parties involved in the DNR order process. From what we learned, we developed an easy to use, specific form for Resuscitation Status and a Medical Treatment Plan. Surveillance of form use indicates we have addressed unrealistic expectations about efficacy of CPR, improved documentation of Do Not Attempt Resuscitation (DNAR) discussions, and clarified DNAR orders and other medical treatments intended for DNAR patients.

Cardiopulmonary Resuscitation↗
PubMed1999

Iliotibial band friction syndrome: MR imaging findings in 16 patients and MR arthrographic study of six cadaveric knees.

PURPOSE: To define magnetic resonance (MR) imaging findings in patients with the iliotibial band friction syndrome (ITBFS) and to correlate these findings with anatomic features defined at magnetic resonance (MR) arthrography in cadavers. MATERIALS AND METHODS: The anatomic relationship of the iliotibial tract (ITT) to the lateral recesses of the knee joint and the lateral femoral epicondyle was investigated with MR arthrography at full extension and at 30 degrees and 60 degrees of knee flexion in six cadaveric knees. Seventeen MR imaging studies in 16 patients with ITBFS were evaluated. RESULTS: In the cadaveric study, no interference of the lateral synovial recess with the lateral femoral epicondyle at full extension and at 30 degrees and 60 degrees of knee flexion was observed. In all specimens, correlation of MR images with macroscopic and microscopic sections revealed no primary bursa between the lateral femoral epicondyle and the ITT. In clinical studies, MR imaging findings of poorly defined signal intensity abnormalities or circumscribed fluid collections were located in a compartmentlike space confined laterally by the ITT and medially by the meniscocapsular junction, the lateral collateral ligament, and the lateral femoral epicondyle. CONCLUSION: MR imaging accurately depicts the compartmentlike distribution of signal intensity abnormalities in patients with ITBFS.

Adolescent↗
PubMed1998

Musculoskeletal ultrasonography.

This article introduces ultrasound in the evaluation of the musculoskeletal system. An emphasis is placed on currently accepted applications, and examples are included to illustrate pathologic conditions. Topics of current investigations are also presented. The efficacy of ultrasound, combined with its inaccessibility and low cost, has earned it an important role in musculoskeletal imaging.

Connective Tissue↗
PubMed1998

Elbow effusions: distribution of joint fluid with flexion and extension and imaging implications.

RATIONALE AND OBJECTIVES: The authors study the distribution of elbow joint fluid with flexion and extension of the joint and evaluate the imaging implications of such distribution. METHODS: Three cadaveric elbows were studied with radiography, ultrasonography, and magnetic resonance imaging after the incremental injections of 1 to 15 mL of saline solution into the elbow joint. Imaging was obtained with full flexion and extension of the joint. Anatomic sections were obtained for correlation. RESULTS: In flexion fluid initially collected posteriorly and, with larger quantities, anteriorly. In extension the anterior fat pad was pressed into its fossa and the posterior fat pad was displaced superiorly by the olecranon process. On lateral radiographs in elbow flexion a positive fat pad sign was seen with 5 to 10 mL of fluid in the joint. Sonography allowed identification of 1 to 3 mL of fluid posteriorly with the elbow flexed. Magnetic resonance imaging allowed identification of 1 mL of fluid, regardless of joint position and location. CONCLUSIONS: The distribution of joint fluid in the elbow is influenced by flexion and extension of the joint. Radiography is best performed in flexion. Sonography is more sensitive than radiography in diagnosing effusions, but should be performed along the olecranon fossa with the elbow flexed. Magnetic resonance imaging is most sensitive in identifying effusions, regardless of joint position or location.

Body Fluids↗
PubMed1998

Wooden foreign bodies in soft tissue: detection at US.

PURPOSE: To evaluate the use of ultrasound (US) for detection of wooden foreign bodies implanted in cadaveric specimens. MATERIALS AND METHODS: Wooden foreign bodies were randomly placed in the plantar soft tissues of three cadaver feet by using 5-mm-long incisions. Ten foreign bodies were 2.5 x 1.0 mm (length x diameter); 10 were 5.0 x 1.0 mm. Ten incisions were performed without implantation of foreign bodies. Three musculoskeletal radiologists independently performed US in blinded fashion and recorded the presence of a foreign body. Each used 7.5- and 10-MHz linear-array transducers and was informed of the possible presence of a foreign body. RESULTS: Sensitivity and specificity for detection of 2.5-mm-long foreign bodies were 86.7% and 96.7%, respectively. Sensitivity and specificity for detection of 5.0-mm-long foreign bodies were 93.3% and 96.7%, respectively. Overall sensitivity was 90.0%, with specificity of 96.7%, accuracy of 92.3%, positive predictive value of 98.0%, and negative predictive value of 83.0%. CONCLUSION: US can be used effectively to locate wooden foreign bodies as small as 2.5 mm in length. Given that many foreign bodies are radiographically undetectable, the accuracy and availability of US make it an excellent modality for evaluation of radiolucent foreign bodies.

Cadaver↗
PubMed1998

Hip joint fluid: detection and distribution at MR imaging and US with cadaveric correlation.

PURPOSE: To define the magnetic resonance (MR) imaging appearance of a hip effusion. MATERIALS AND METHODS: Fifty-two asymptomatic hips in 26 volunteers aged 20-37 years and five fractured hips were imaged at 1.5 T with T2-weighting in three planes. Images were computer digitized and analyzed for hip fluid volume and visually assessed for the presence and width of fluid pockets (in millimeters) seen in the acetabular notch; recesses anterior, posterior, and lateral to the femoral head; and recesses anterior, posterior, and medial to the femoral neck. Cadaveric hips were also injected with graduated amounts of saline (1-20 mL), and sequential MR and ultrasound images were obtained. RESULTS: Computer analysis yielded an average fluid volume of 2.7 mL (range, 0.7-5.6 mL) in asymptomatic and 6.1 mL (range, 1.7-11.6 mL) in symptomatic hips. The mean difference between the right and left hips was 0.8 mL (range, 0.0-2.9 mL). Discrete fluid pockets, sometimes measuring greater than 5 mm in width, were commonly seen in asymptomatic hips. Distention of the capsule by at least 5 mm along the length of the femoral neck was almost always seen after injection of 5 mL of saline and was consistently seen after injection of 10 mL of saline into cadaveric hips. CONCLUSION: Fluid adjacent to the entire length of the femoral neck, measuring at least 5 mm in width, is compatible with a joint effusion.

Acetabulum↗
PubMed1998

Detection of ankle effusions: comparison study in cadavers using radiography, sonography, and MR imaging.

OBJECTIVE: The purpose of this study was to compare radiography, sonography, and MR imaging in revealing ankle effusions in cadaveric specimens. MATERIALS AND METHODS: Known quantities of saline solution were instilled in increments into the ankle joints of three cadaveric specimens. Imaging was completed after each injection with the ankle in dorsiflexion, plantar flexion, and a neutral position. Imaging included radiography, sonography, and MR imaging. Three observers who were aware of possible joint fluid evaluated the images by consensus and determined the presence or absence of joint effusion. RESULTS: MR imaging revealed 1 ml of fluid within the anterior recess of the ankle in a neutral position and in plantar flexion and within the posterior recess in dorsiflexion. Sonography revealed 2 ml of fluid within the anterior recess in a neutral position and in plantar flexion. Radiography revealed 5 ml of fluid within the anterior recess in a neutral position. CONCLUSION: MR imaging, sonography, and lateral radiography, in order of decreasing sensitivity, revealed ankle effusion. The power to reveal with each technique is influenced by the precise position of the ankle.

Adipose Tissue↗
PubMed1998

Longitudinal split of the peroneus longus and peroneus brevis tendons with disruption of the superior peroneal retinaculum.

Longitudinal split and subluxation of the peroneus brevis tendon have been reported in surgery literature, but few publications report on longitudinal tears of the peroneus longus tendon. The most likely proposed mechanism is a mechanical one. This report discusses the ultrasonographic appearance of peroneus longus and peroneus brevis tendon splits and the mechanism of injury.

Ankle Injuries↗
PubMed1997

Pseudarthrosis: US evaluation after posterolateral spinal fusion: work in progress.

PURPOSE: To determine the value of ultrasound (US) in evaluation of pseudarthrosis after posterolateral spinal fusion. MATERIALS AND METHODS: In 10 patients who had undergone bilateral posterolateral thoracic or lumbar fusion with autologous bone graft and instrumentation more than 9 months previously, US was performed within 1 week before second-look surgery. A total of 20 sites each side of midline were evaluated for the presence of bone graft, solid fusion, clefts, fluid collections, and hardware visibility. US findings were compared with those at surgery. In three patients, standard radiographs were reviewed before US; blinded US evaluation was performed in the remaining seven patients. RESULTS: At US, all 10 sites of pseudarthrosis seen at surgery were identified correctly. Of 10 sites with solid fusion at surgery, US depicted six. At four sites (two patients), fusion was mistaken for or obscured by hardware. Overall, sensitivity was 100%, specificity was 60%, and accuracy was 80%. CONCLUSION: US can play a valuable role in the detection of posterolateral bone graft pseudarthrosis, especially when hardware is present.

Adult↗