Anna Hirschmann

Do Chondral Lesions of the Knee Correlate with Bone Tracer Uptake by Using SPECT/CT?

PURPOSE To evaluate the correlation of bone tracer uptake as determined with single photon emission computed tomography (SPECT)/computed tomography (CT) and the size and severity of chondral lesions detected with magnetic resonance (MR) imaging of the knee. MATERIALS AND METHODS MR imaging and SPECT/CT images of 63 knee joints in 63 patients (mean age ± standard deviation, 49.2 years ± 12.7) with chondral or osteochondral lesions were prospectively collected and retrospectively analyzed after approval by the ethics committee. Chondral lesions were graded on MR images by using a modified Noyes grading scale (grade 0, intact; grade 1, fibrillations; grade 2, <50% defect; grade 3, >50% defect; and grade 4, grade three plus subchondral changes) and measured in two dimensions. Technetium 99m hydroxymethane diphosphonate SPECT/CT bone tracer uptake was volumetrically quantified by using validated software. Maximum values of each subchondral area (patellofemoral or medial and lateral femorotibial) were quantified, and a ratio was calculated in relation to a reference region in the femoral shaft, which represented the bone tracer uptake background activity. Grades and sizes of chondral lesions and bone tracer uptake were correlated by using an independent t test and analysis of variance (P < .05). RESULTS Bone tracer uptake was low (mean relative uptake, 1.64 ± 0.95) in knees without any present chondral lesion. In knees with grade 3 and 4 chondral lesions, the relative ratio was significantly higher (3.62 ± 2.18, P = .002) than in knees with grade 1 and 2 lesions (2.95 ± 2.07). The larger the diameter of the chondral lesion, the higher the bone tracer uptake. Higher grades of chondral lesions (grades 3 and 4) larger than 4 cm(2) (4.96 ± 2.43) showed a significantly higher bone tracer uptake than smaller lesions (<1 cm(2), 2.72 ± 1.43 [P = .011]; and 1-4 cm(2), 3.28 ± 2.15 [P = .004]). CONCLUSION SPECT/CT findings significantly correlate with the degree and size of chondral lesions on MR images. Grade 3 and 4 chondral lesions of the knee, as well as larger lesions, correlate with a high bone tracer uptake.

MRI of the Thumb: Anatomy and Spectrum of Findings in Asymptomatic Volunteers

UNLABELLED OBJECTIVE.:The purpose of this article is to analyze the MR anatomy and variable imaging characteristics of the thumb in asymptomatic volunteers. SUBJECTS AND METHODS MRI of the thumb was obtained in 34 asymptomatic volunteers (mean age, 33.9 ± 9.2 years). Two radiologists independently assessed visibility and signal intensity (SI) and thickness of the following structures of the metacarpophalangeal and interphalangeal joints: proper and accessory radial and ulnar collateral ligaments, volar and dorsal plates, adductor pollicis aponeurosis, and annular pulleys. The presence and size of a synovial recess at the base of all plates was assessed. RESULTS On intermediate-weighted fat-saturated images, the ulnar collateral ligament of the metacarpophalangeal joint (reader 1, 79%; reader 2, 62%) and the adductor pollicis aponeurosis (reader 1, 50%; reader 2, 82%) commonly had a striated appearance. The radial collateral ligament of both joints was mainly of low SI (metacarpophalangeal joint, 53% for reader 1 and 85% for reader 2; interphalangeal joint, 59% for reader 1 and 82% for reader 2). All four pulleys were visible in each volunteer. An intermediate SI was observed in almost all pulleys, whereas the variable annular pulley had predominantly a low SI (reader 1, 50%; reader 2, 74%). The ulnar collateral ligament of the metacarpophalangeal joint is typically less than 3 mm thick, and the radial collateral ligament is less than 2 mm thick. A full-thickness synovial recess at the base of the dorsal plate of the metacarpophalangeal joint was seen in almost all volunteers (reader 1, 97%; reader 2, 100%). CONCLUSION The ligaments and pulleys of the thumb show considerable variability on MRI in healthy volunteers. The ulnar collateral ligament of the metacarpophalangeal joint is typically striated and less than 3 mm thick. A full-thickness synovial recess at the base of the dorsal plate of the metacarpophalangeal joint is a normal finding and should not be misdiagnosed as a tear.

Chronic Knee Pain: Clinical Value of MRI versus SPECT/CT.

MRI and single-photon emission computed tomography/computed tomography (SPECT/CT) are important imaging methods for the evaluation of chronic knee pain. MRI is the current gold standard for the assessment of soft tissue, chondral, and bony pathologies of the knee joint. In the last decade, SPECT/CT has been increasingly recognized and used for a variety of orthopedic problems. The major indication for SPECT/CT is evaluation of patients with chronic knee pain. It is particularly helpful in patients with overloading problems, chondral or osteochondral lesions, and unhappy patients with ongoing pain after arthroplasty.This review illustrates clinical relevant imaging findings in the evaluation of chronic knee pain using MRI and SPECT/CT. Potential limitations of both modalities are discussed. A future perspective of SPECT/CT arthrography is provided.

Quality Management in Musculoskeletal Imaging: Form, Content, and Diagnosis of Knee MRI Reports and Effectiveness of Three Different Quality Improvement Measures

OBJECTIVE The purpose of this article is to evaluate the quality of reports of knee MRI examinations in form, content, and diagnosis and to assess the effect of three different quality improvement measures. MATERIALS AND METHODS Reports of 500 knee MRI examinations (first round, or baseline) were reviewed retrospectively by five musculoskeletal radiologists. Fifteen different criteria were assessed for formal and content-related quality of reports. Diagnostic discrepancies were categorized using a 5-point scale, as follows: I, no deviation; II, undetected finding, clinically irrelevant; III, wrong interpretation of finding, clinically irrelevant; IV, undetected finding, clinically relevant; and V, wrong interpretation of finding, clinically relevant. Then three different quality improvement measures were applied prospectively to a total of 510 consecutive reports: a quiet work environment, double reading, and the use of a structured report template. These 510 knee MRI reports (second round) were evaluated using the same criteria. RESULTS A statistically significant improvement in 13 of 15 criteria was found in the second-round reports: orthographic errors improved from 32.4% to 22.0% (p < 0.001) of reports and digital speech recognition errors improved from 8.4% to 7.6% (p = 0.660). Missing anatomic structures decreased from 6.3% to 0.4%. Diagnostic discrepancies were less frequently found (12.9% vs 20.8%; p = 0.001), along with the following changes in categorization (first-round results are in parentheses): I, 87.1% (79.2%); II, 9.2% (16.8%); III, 2.3% (1.0%); IV, 1.0% (2.6%); and V, 0.4% (0.4%). Quality improvement was found in all three measure groups, without statistical significance among the groups, except for the orthographic errors (p < 0.001), which were most common in the template group. CONCLUSION All three quality improvement measures significantly improved the quality of the knee MRI reports, but no measure was clearly superior to the others.

Synchronous MRI of muscle motion induced by electrical stimulation

Assessing the functionality of muscle fibers is essential to monitor both pathological and physiological processes. Here, we present a new method for accurate, quantitative measurement of muscle contraction with magnetic resonance imaging (MRI) using an electrical muscle stimulator (EMS), hence allowing the direct assessment of muscle kinematics.

Meniscal pathologies on MRI correlate with increased bone tracer uptake in SPECT/CT

ObjectivesTo assess the relationship of subchondral bone tracer uptake (BTU) on SPECT/CT and meniscal pathologies on MRI in patients with painful knees.MethodsTwenty-five patients who had MRI and SPECT/CT within 3 months without knee surgery or grade ≥3 cartilage lesions were prospectively included. Maximum values of each subchondral femorotibial area were quantified and a ratio was calculated in relation to a femoral shaft reference region, which represented the BTU background activity. Meniscal lesions were graded (intact/degeneration/tear) and meniscal extrusion (no/yes) was assessed using MRI by two musculoskeletal radiologists blinded to the SPECT/CT findings. One-tailed Spearman correlations served for statistics (p < 0.05).ResultsKnees with meniscal degeneration or tear showed a significantly higher BTU in the medial femorotibial compartment (p = 0.045) when compared to intact menisci. Meniscal degeneration was associated with an increased BTU in the lateral femorotibial compartment; however, this was not statistically significant (p = 0.143). Patients with an extruded meniscus showed significantly higher BTU compared to a non-extruded meniscus (p < 0.020).ConclusionsMedial femorotibial BTU in SPECT/CT was associated with meniscal pathologies. Highest BTU was found in patients with meniscal tears. SPECT/CT appears to be a useful imaging modality to identify patients with overloading or early osteoarthritis.Key Points•Meniscal degeneration and tears correlate significantly with increased BTU using SPECT/CT.•Medial meniscus extrusion is associated with an increased BTU in SPECT/CT.•SPECT/CT allows detection of overloading and early osteoarthritis.

Imaging of Chopart (Midtarsal) Joint Complex: Normal Anatomy and Posttraumatic Findings

OBJECTIVE The objective of this article is to review the normal anatomy and posttraumatic findings of the Chopart joint complex. Key imaging features of the normal ligaments and patterns of ligamentous and osseous injuries are discussed. CONCLUSION Traumatic midtarsal injuries, particularly midtarsal sprain, are often overlooked clinically and on imaging but are relatively common and typically are associated with inversion ankle injuries. Radiologists should be familiar with Chopart joint anatomy and the imaging features of midtarsal injuries because early diagnosis may help optimize clinical management.

Greater Trochanteric Pain Syndrome: Abductors, External Rotators

Abstract Chronic pain and tenderness at the greater trochanter characterizes trochanteric pain syndrome. For a long time, trochanteric bursitis was thought to be the only underlying pathology; however, investigations have shown that tendinopathy of the abductors is the main cause, followed by iliotibial band thickening and, to a lesser extent, abductor tendon tears. Trochanteric bursitis can be associated with it. On magnetic resonance imaging (MRI), peritrochanteric T2 abnormalities are evident in greater trochanteric pain syndrome. However, this is also frequently encountered in asymptomatic patients. In the postoperative setting, patients with total hip arthroplasties and transtendinous lateral or posterior surgical access are prone to tendon injury. Symptomatic patients typically present with tendon tears, whereas peritrochanteric fluid, thickening, and signal alterations of the abductors and fatty atrophy of the gluteus minimus muscle are often encountered in asymptomatic postoperative hips. MRI and ultrasound are proven and reliable imaging modalities in patients with greater trochanteric pain syndrome. Awareness of typical imaging findings, in particular in postoperative patients, are helpful in the evaluation of patients.

JOURNAL CLUB: MRI Evaluation of Midtarsal (Chopart) Sprain in the Setting of Acute Ankle Injury

OBJECTIVE This study determined the frequency and MRI appearance of osseous and ligamentous injuries in midtarsal (Chopart) sprains and their association with ankle sprains after acute ankle injuries. Prospective diagnosis of and interobserver agreement regarding midtarsal injury among musculoskeletal radiologists were also assessed. SUBJECTS AND METHODS Two cohorts with ankle MRI were identified via a digital PACS search: patients who had undergone MRI within 8 weeks after ankle injury and control subjects who had not sustained ankle trauma. Studies were retrospectively reviewed in consensus as well as independently, assessing ligamentous and osseous injury to the Chopart joint (calcaneocuboid and talonavicular joints) and associated lateral collateral and deltoid ligamentous injury. Interobserver agreement was calculated, and prospective radiology reports were reviewed to determine the musculoskeletal radiologists familiarity with Chopart joint injury. RESULTS MR images of control subjects (n = 16) and patients with ankle injury (n = 47) were reviewed. The normal dorsal calcaneocuboid and calcaneocuboid component of bifurcate ligaments were variably visualized; the remaining normal ligaments were always seen. Eleven patients (23%) had midtarsal ligamentous and osseous injury consistent with midtarsal sprain (eight acute or subacute, one probable, and two old). Six (75%) of eight acute or subacute cases had coexisting lateral collateral ligament injury. Eighty-nine percent of osseous injuries were reported prospectively, but 83% of ligamentous injuries were missed. Substantial interobserver agreement was achieved regarding diagnosis of midtarsal sprain. CONCLUSION Midtarsal sprains are commonly associated with acute ankle injury and with ankle sprains. Presently, midtarsal sprains may be underrecognized by radiologists; thus, greater familiarity with the MRI spectrum of ligamentous and osseous injuries at the Chopart joint is important for accurate diagnosis and clinical management.

Patients with problems after ACL reconstruction - what do help MRI and SPECT/CT?

Aims and Objectives: Magnetic resonance imaging (MRI) and single-photon emission computed tomography/ computed tomography (SPECT/CT) are established diagnostic instruments for symptomatic patients after ACL reconstruction. The purpose of the study was to compare and correlate MRI and SPECT/CT findings of symptomatic patients after ACL reconstruction. Materials and Methods: In a retrospective study 30 knees of symptomatic patients complaining about pain and/or instability after ACL reconstruction were investigated using 99mTc-HDP SPECT/CT and MRI. In MRI signs of a graft tear (partial and complete) were noted. Graft signal intensity, bone bruise, cyst formation in proximal, medial and distal femoral and tibial tunnels, roof impingement, roof osteophytes, graft arthrofibrosis, knee joint effusion and synovial thickness were classified. Measurements were performed by two musculoskeletal radiologists. The agreement of the assessed MR signs were calculated using cohen’s kappa coefficient. These showed excellent (kappa >0.75) to good (kappa >0.40) reproducibility between the readings of the two observers. Quantitative grading of bone tracer uptake (BTU) for each anatomical area of a previously validated localisation scheme was done. Tunnel width was assessed in CT at three different levels for femoral and tibial tunnels. The findings in SPECT/CT and MRI were correlated (p<0.05). Results: Increased BTU in most femoral and tibial knee regions was found in patients with MR findings of knee joint effusion, synovial thickening and bone bruise in various knee regions. A reciprocal correlation was shown for cyst formation in the central and distal area of the femoral tunnel and BTU in the femoral tunnel. MR findings such as graft continuity, graft signal intensity in the femoral and tibial tunnel, roof impingement, roof osteophytes did not show a significant correlation. A reciprocal correlation was revealed for tunnel enlargement in the proximal and central femoral tunnel and MR signal intensity in the entire intra-articular graft. Cyst formation in the femoral tunnel significantly correlated with tunnel enlargement in the proximal and central part of the femoral tunnel. Proximal femoral cyst formation also correlated with tibial tunnel enlargement in the central and distal part. BTU did show a positive correlation with tibial tunnel enlargement and a negative correlation with femoral tunnel enlargement. Conclusion: Both imaging modalities play an important role in postoperative diagnostics of patients with problems after ACL reconstruction. The results of our study could help in clinical decision-making to accurately identify causes of painful ACL reconstructions. MRI will remain the primary imaging modality, but SPECT/CT could be helpful giving information on in-vivo loading of the knee.