Basic considerations before injections and scanning techniques

Improving Needle Tip Tracking and Detection in Ultrasound-Based Navigation System Using Deep Learning-Enabled Approach

Ultrasound-guided percutaneous interventions have numerous advantages over traditional techniques. Accurate needle placement in the target anatomy is crucial for successful intervention, and reliable visual information is essential to achieve this. However, previous studies have revealed several challenges, such as the variability in needle echogenicity and the common misalignment of the ultrasound beam and the needle. Advanced techniques have been developed to optimize needle visualization, including hardware-based and image-processing-based methods. This paper proposes a novel strategy of integrating ultrasound-based deep learning approaches into an optical navigation system to enhance needle visualization and improve tip positioning accuracy. Both the tracking and detection algorithms are optimized utilizing optical tracking information. The information is introduced into the tracking network to define the search patch update strategy and form a trajectory reference to correct tracking results. In the detection network, the original image is processed according to the needle insertion position and current position given by the optical localization system to locate a coarse region, and the depth-score criterion is adopted to optimize detection results. Extensive experiments demonstrate that our approach achieves promising tip tracking and detection performance with tip localization errors of 1.11 ± 0.59 mm and 1.17 ± 0.70 mm, respectively. Moreover, we establish a paired dataset consisting of ultrasound images and their corresponding spatial tip coordinates acquired from the optical tracking system and conduct real puncture experiments to verify the effectiveness of the proposed methods. Our approach significantly improves needle visualization and provides physicians with visual guidance for posture adjustment.

Current Approaches to Four Challenging Pain Syndromes

During a conference of pain specialists, some of the experts addressed the potential management of four prevalent but difficult painful conditions, namely, chronic postsurgical pain (CPSP), knee osteoarthritis, chest trauma, and facet joint arthropathy. In all cases, the conditions posed challenges in accurate diagnoses as well as safe, effective treatments, especially using locoregional blocks. It is not clear why some surgical patients develop CPSP and others do not, although some risk factors have been identified. More importantly, the transitional phase of pain from acute to chronic deserves greater scrutiny. It appears as if more aggressive and more effective perioperative and postoperative analgesia could help mitigate or possibly prevent CPSP. Knee osteoarthritis is prevalent but is often managed pharmacologically and then with joint replacement; many patients simply live with the condition which can be viewed as a disease of the entire joint. New approaches with intra-articular injections of hyaluronic acid, platelet-rich plasma, and botulinum toxin may provide safe, effective, and durable pain control. Chest trauma can be extremely painful and a source of morbidity, but its management tends to rely on watchful waiting and drug therapy. New approaches to regional nerve blocks can be beneficial and may reduce troublesome symptoms such as the inability to cough or clear the lungs. Facet joint arthropathy is very prevalent among older people but is not completely clarified. It may be the source of intense pain with limited management strategies. The role of nerve blocks in facet joint arthropathy is an important new addition to the armamentarium of pain management, particularly for geriatric patients.

Shoulder MR Arthrography: Comparative Evaluation of Three Different Contrast Injection Techniques Using an Anterior Approach

BACKGROUND

MR arthrography (MRA) is commonly used in the assessment of shoulder internal derangements. Correct intra-articular contrast injection is required for this modality. Anterior injections under fluoroscopic, ultrasound-guidance, or without image-guidance have been described in the literature. However, no simultaneous comparison has been performed between the three techniques.

PURPOSE

To compare the accuracy and performance of fluoroscopy (FL)-guided, ultrasound (US)-guided and non-image-guided intra-articular contrast injection via an anterior approach for performing shoulder MRA.

STUDY TYPE

Prospective.

SUBJECTS

Two-hundred and ten patients (180 men and 30 women; mean age, 33 ± 12 years; range 20-60 years) with clinically suspected shoulder pathology.

FIELD STRENGTH/SEQUENCE

1.5T/fat-suppressed T₁ -weighted, T₂ -weighted, and 3D-gradient-echo images.

ASSESSMENT

Patients underwent shoulder MRA after anterior intra-articular contrast injection under FL- or US-guidance or without image-guidance. Patients were randomized among the three techniques with each group comprising 70. The techniques were compared according to the accuracy of intra-articular needle placement, attempts success rate, pain during and 24 hours after injection, procedure times, contrast extravasation rate, joint distension, and MRA diagnostic efficacy. Pain was assessed by the visual analog scale (VAS) pain-score.

STATISTICAL TESTS

Pearson's chi-squared and Kruskal-Wallis tests.

RESULTS

FL- and US-guided injections (100% accuracy) were significantly more accurate than non-image-guided (85.7% accuracy) (P < 0.05). US-guidance was the least painful, with statistical differences between image-guided and non-image-guided techniques regarding the first attempt success rate (95.7% and 92.8% for FL- and US-guided vs. 78.6% for blinded), VAS-score 24 hours-post-procedure (1.7 ± 1.7, and 1.5 ± 1.4 vs. 2.2 ± 1.4), procedure time (11.9 ± 1.6, and 7.4 ± 1.7 vs. 4.3 ± 0.76 minutes), and contrast extravasation rate (5.7%, and 8.6% vs. 30%) (all P < 0.05). Procedure time was also significantly different between FL and US-guidance (P < 0.05).

DATA CONCLUSION

Imaging-guided injections are more accurate and tolerable than non-image-guided and should be considered to confirm intra-articular needle position, hence adequate capsular distension and good diagnostic quality of shoulder MRA. US guidance is a less painful, rapid, and safe alternative to the FL approach. Evidence Level: 2 Technical Efficacy Stage: 5. J. MAGN. RESON. IMAGING 2021;53:481-490.

Novel ultrasound-guided lateral approach for femoral nerve block in cats: a pilot study

OBJECTIVES

The aim of this study was to describe the technique for a novel lateral approach to femoral nerve block in cat cadavers.

METHODS

Five feline cadavers were used in our prospective cadaveric experimental study. Ultrasonography was used to identify the anatomy injection site. Both pelvic limbs were injected with a volume (0.1 ml/kg) of methylene blue in each cat. The cadavers were placed in lateral recumbency, with the limb to be blocked positioned uppermost. The transducer was held perpendicular to the most proximal area of the pelvic limb, ventral to the greater trochanter and slightly cranial to the femur. Methylene blue was injected after the localisation of the femoral nerve. Immediately after the injection, the cat was turned and the technique was repeated on the contralateral side. After performing the 'block' in both limbs, the area was dissected bilaterally and the success was evaluated. A positive femoral nerve staining was considered for a coverage of ⩾1 cm.

RESULTS

A total of 10 ultrasound-guided femoral nerve injections were performed. Ninety percent (n = 9/10) of the nerves were successfully dyed.

CONCLUSIONS AND RELEVANCE

The novel ultrasound-guided lateral approach may be suitable and reproducible for a successful femoral nerve blockade in cats. Further investigations about the clinical usefulness and safety of this femoral nerve block in live cats are required.