CT-guided cervical nerve root injections: comparing the immediate post-injection anesthetic-related effects of the transforaminal injection with a new indirect technique

Objective: To describe an "indirect” cervical nerve root injection technique with a dorsal approach that should carry less inherent risk than the "direct” cervical transforaminal injection approach, and to compare the immediate post-injection results of the two procedures. Materials and methods: The indirect and direct cervical nerve root injection procedures are described in detail. Fifty-three consecutive patients receiving the indirect nerve root injections during 2009-2010 were age- and gender-matched to 53 patients who underwent direct transforaminal nerve root injections performed in 2006. Pain level data were collected immediately before and 20-30min after each procedure. The percentages of pain change in the two groups were compared using the unpaired Student'st test. Results: Fifty-two men (mean age 49) and 54 women (mean age 55) were included. The mean percentage of pain reduction for patients receiving indirect nerve root injections was 38.4% and for those undergoing the direct nerve root injections approach it was 43.2%. This was not significantly different (P = 0.455). No immediate or late adverse effects were reported after either injection procedure. Conclusions: The indirect cervical nerve root injection procedure is a potentially safer alternative to direct cervical transforaminal nerve root injections. The short-term pain reduction is similar using the two injection method

Three-dimensional hindfoot alignment measurements based on biplanar radiographs: comparison with standard radiographic measurements

Objective: To establish a hindfoot alignment measurement technique based on low-dose biplanar radiographs and compare with hindfoot alignment measurements on long axial view radiographs, which is the current reference standard. Materials and methods: Long axial view radiographs and low-dose biplanar radiographs of a phantom consisting of a human foot skeleton embedded in acrylic glass (phantom A) and a plastic model of a human foot in three different hindfoot positions (phantoms B1-B3) were imaged in different foot positions (20° internal to 20° external rotation). Two independent readers measured hindfoot alignment on long axial view radiographs and performed 3D hindfoot alignment measurements based on biplanar radiographs on two different occasions. Time for three-dimensional (3D) measurements was determined. Intraclass correlation coefficients (ICC) were calculated. Results: Hindfoot alignment measurements on long axial view radiographs were characterized by a large positional variation, with a range of 14°/13° valgus to 22°/27° varus (reader 1/2 for phantom A), whereas the range of 3D hindfoot alignment measurements was 7.3°/6.0° to 9.0°/10.5° varus (reader 1/2 for phantom A), with a mean and standard deviation of 8.1° ± 0.6/8.7° ± 1.4 respectively. Interobserver agreement was high (ICC = 0.926 for phantom A, and ICC = 0.886 for phantoms B1-B3), and agreement between different readouts was high (ICC = 0.895-0.995 for reader 1, and ICC = 0.987-0.994 for reader 2) for 3D measurements. Mean duration of 3D measurements was 84 ± 15/113 ± 15s for reader 1/2. Conclusion: Three-dimensional hindfoot alignment measurements based on biplanar radiographs were independent of foot positioning during image acquisition and reader independent. In this phantom study, the 3D measurements were substantially more precise than the standard radiographic measurement

Abductor tendon tears are associated with hypertrophy of the tensor fasciae latae muscle

Objective: To evaluate the association between hypertrophy of the tensor fasciae latae muscle and abductor tendon tears. Materials and methods: Thirty-five patients who underwent MRI of the abductor tendons of the hip were included in this retrospective study. A subgroup of 18 patients was examined bilaterally. The area of the tensor fasciae latae muscle and the area of the sartorius muscle (size reference) were quantified at the level of the femoral head, and a ratio was calculated. Two radiologists assessed the integrity of the gluteus medius and minimus tendon in consensus. Data were analyzed with a Mann-Whitney U test. Results: Sixteen out of 35 patients (46%) had a tear of the gluteus medius or minimus tendon. The ratio of the area of the tensor fasciae latae to the sartorius muscle was significantly higher (p = .028) in the group with an abductor tendon tear (median 2.25; Interquartile Range [IQR] = 1.97-3.21) compared to the group without any tears (median 1.91; IQR = 1.52-2.26). The bilateral subanalysis showed that in patients without a tear, the ratio of the two areas did not differ between each side (p = .966), with a median of 1.54 (primary side) and 1.76 (contralateral side). In patients with an abductor tendon tear the ratio was significantly higher (p = .031) on the side with a tear (median 2.81) compared to the contralateral healthy side (1.67). Conclusion: Patients with abductor tendon tears showed hypertrophy of the tensor fasciae latae muscle when compared to the contralateral healthy side and to patients without a tea

Ligaments of the Lisfranc joint in MRI: 3D-SPACE (sampling perfection with application optimized contrasts using different flip-angle evolution) sequence compared to three orthogonal proton-density fat-saturated (PD fs) sequences

Purpose: To compare the detection rate and visibility of the ligaments in the Lisfranc joint with a single 3D (−SPACE) MR sequence and three orthogonal PD fat-saturated sequences. Materials and methods: Thirty-one asymptomatic feet and 15 patients with posttraumatic pain in the Lisfranc joint were evaluated with a 3D-SPACE-sequence (0.5mm section thickness, acquisition time 10:22min, secondary reformations) and three orthogonal PD fs sequences (2mm section thickness, 9:20min). The Lisfranc-ligament, the dorsal and plantar tarsometatarsal ligaments (TMT), the dorsal, interosseous, and plantar intermetatarsal ligaments (IMT) (24 ligaments for each foot) were assessed. Results: In asymptomatic feet, 692 ligaments were detected with the SPACE sequence, thereof 90.6% exhibited normal signal, and most (96.9%) were completely visible on one single image. A total of 659 ligaments were detected with the PD fs sequence, thereof 86.6% yielded normal signal, and 28.5% were completely visible on one single image. In patients, 327 ligaments were detected with SPACE, thereof 50.6% appeared completely visible with high signal. On PD fs, 308 ligaments were detected, 42.2% of the ligaments had high signals. Conclusions: The ligaments of the Lisfranc joint are better detected with a single 3D-SPACE sequence and secondary reformations than with three orthogonal PD fs sequence

MR angiography with parallel acquisition for assessment of the visceral arteries: comparison with conventional MR angiography and 64-detector-row computed tomography

The purpose of the study was to retrospectively compare three-dimensional gadolinium-enhanced magnetic resonance angiography (conventional MRA) with MRA accelerated by a parallel acquisition technique (fast MRA) for the assessment of visceral arteries, using 64-detector-row computed tomography angiography (MDCTA) as the reference standard. Eighteen patients underwent fast MRA (imaging time 17s), conventional MRA (29s) and MDCTA of the abdomen and pelvis. Two independent readers assessed subjective image quality and the presence of arterial stenosis. Data were analysed on per-patient and per-segment bases. Fast MRA yielded better subjective image quality in all segments compared with conventional MRA (P = 0.012 for reader 1, P = 0.055 for reader 2) because of fewer motion-induced artefacts. Sensitivity and specificity of fast MRA for the detection of arterial stenosis were 100% for both readers. Sensitivity of conventional MRA was 89% for both readers, and specificity was 100% (reader 1) and 99% (reader 2). Differences in sensitivity between the two types of MRA were not significant for either reader. Interobserver agreement for the detection of arterial stenosis was excellent for fast (κ = 1.00) and good for conventional MRA (κ = 0.76). Thus, subjective image quality of visceral arteries remains good on fast MRA compared with conventional MRA, and the two techniques do not differ substantially in the grading of arterial stenosis, despite the markedly reduced acquisition time of fast MR

Managing hardware-related metal artifacts in MRI: current and evolving techniques

Magnetic resonance imaging (MRI) around metal implants has been challenging due to magnetic susceptibility differences between metal implants and adjacent tissues, resulting in image signal loss, geometric distortion, and loss of fat suppression. These artifacts can compromise the diagnostic accuracy and the evaluation of surrounding anatomical structures. As the prevalence of total joint replacements continues to increase in our aging society, there is a need for proper radiological assessment of tissues around metal implants to aid clinical decision-making in the management of post-operative complaints and complications. Various techniques for reducing metal artifacts in musculoskeletal imaging have been explored in recent years. One approach focuses on improving hardware components. High-density multi-channel radiofrequency (RF) coils, parallel imaging techniques, and gradient warping correction enable signal enhancement, image acquisition acceleration, and geometric distortion minimization. In addition, the use of susceptibility-matched implants and low-field MRI helps to reduce magnetic susceptibility differences. The second approach focuses on metal artifact reduction sequences such as view-angle tilting (VAT) and slice-encoding for metal artifact correction (SEMAC). Iterative reconstruction algorithms, deep learning approaches, and post-processing techniques are used to estimate and correct artifact-related errors in reconstructed images. This article reviews recent developments in clinically applicable metal artifact reduction techniques as well as advances in MR hardware. The review provides a better understanding of the basic principles and techniques, as well as an awareness of their limitations, allowing for a more reasoned application of these methods in clinical settings

Imaging of the Hip

Imaging evaluation of the hip joint requires expert knowledge about the detailed anatomy and specific injuries. This chapter will include various osseous pathologies that can affect the hip joint such as stress fractures, osteonecrosis, or subchondral insufficiency fractures. Several types of mechanical impingement between the osseous components of the hip joint will be discussed such as femoroacetabular impingement, abnormal antetorsion, and subspine impingement. Detailed evaluation of damage to the labrum, articular cartilage, and other intra-articular structures is described

Sports Injuries: Misinterpretations to Learn From

Athletes present with a variety of both common and specific injuries to the sports physician. For the imaging evaluation of such injuries, this poses special problems to avoid misinterpretations. While some sports injuries are not complicated, other are initially misdiagnosed, leading to possible secondary complications. Further, seemingly abnormal imaging findings in athletes can actually be normal physiological and mechanical phenomenons. Especially in young athletes, a variety of pitfalls are encountered at imaging, such as a focal periphyseal edema or a cortical desmoid. Good communication between the sports physician and the radiologist is paramount in reaching a fast and correct diagnosis in such cases