Age-related prevalence and imaging characteristics of the superior acetabular roof notch in children, adolescents, and young adults

OBJECTIVE

To determine the age-related prevalence and imaging characteristics of the superior acetabular roof notch (SARN) on hip MRI and radiographs in a young study population.

MATERIALS AND METHODS

Retrospective analysis of 304 MRI examinations and corresponding available radiographs of patients between the ages of 4 and 24 years. Two observers classified SARN with fluid-like findings on MRI as type-1, whereas SARN with fat-like findings on MRI were classified as type-2. Sensitivity and specificity of radiographic SARN findings were determined using MRI as the reference standard. Logistic regression models were used to assess the age-related prevalence on MRI.

RESULTS

Twelve patients (3.9%) had fluid-like SARN type-1, 27 patients (8.9%) had fat-like SARN type-2, while 265 patients (87.2%) had no SARN on MRI. The odds ratio (OR) for age (years) with respect to the presence of a fluid-like SARN type-1 on MRI was 0.79 (95% CI: 0.70-0.89), meaning that with each year, the likelihood for SARN type-1 decreased by 21% (p < 0.001). The OR for age with respect to the presence of a fat-like SARN type-2 on MRI was 1.14 (95% CI: 1.02-1.27) (p = 0.017). The diagnostic sensitivity for detecting a SARN on radiographs compared to MRI as the reference standard was between 0.75 and 0.83 and the corresponding specificity was between 0.85 and 0.89 for both observers.

CONCLUSION

SARN is a common finding on MRI and radiographs. The present data suggest that SARN undergoes an age-related imaging characteristic from a fluid-like appearance to a fat-like appearance on MRI during adolescence.

Diagnostic performance of long head of biceps tendon tears on MRI: systematic review and meta-analysis

OBJECTIVES

The purpose of this meta-analysis was to determine the diagnostic performance of conventional MRI and MR arthrography for tendinosis, and partial and complete tears of the long head of the biceps tendon (LHBT) using arthroscopy as the reference standard.

MATERIALS AND METHODS

A systematic review was performed using predefined data fields in PubMed, and all articles published from January 2000 up to April 2022 were retrospectively pooled and reviewed. Six MRI studies on complete tear (n = 555) and ten studies on partial tear/tendinosis (n = 2487) were included in the analysis. Two of the included studies in each group investigated the use of MR arthrography. The data sets were analyzed using a univariate approach with the DerSimonian and Laird random effects model and the proportional hazards model.

RESULTS

MRI shows high specificities in diagnosing complete tears of the LHBT ranging from 93.0 to 99.0%. Diagnostic sensitivity was more heterogeneous ranging from 55.9 to 90.0%. The overall negative likelihood ratio was 0.29 (95% CI: 0.17-0.50) and the overall positive likelihood ratio was 37.3 (95% CI: 11.9-117.4). The mean sensitivity in diagnosing partial tear/tendinosis of the LHBT was 67.8% (95% CI: 54.3-78.9%) and the specificity was 75.9% (95% CI: 63.6-85.0%), resulting in a balanced accuracy of 71.9%. The overall negative likelihood ratio was 0.44 (95% CI: 0.32-0.59) and the overall positive likelihood ratio was 2.64 (95% CI: 1.91-3.65).

CONCLUSION

MRI is highly specific for the diagnosis of complete tears of the LHBT, whereas diagnostic sensitivity was more heterogeneous. The diagnosis of partial tears and/or tendinosis of the LHBT remains challenging on MRI, which may warrant complementary clinical examination or other imaging modalities to increase diagnostic confidence in equivocal cases.

CLINICAL RELEVANCE STATEMENT

Conventional MRI and MR arthrography have high diagnostic performance for complete tendon tear when compared to arthroscopy. The diagnosis of tendinosis/partial tears remains challenging and may require comparison with clinical tests and other imaging modalities.

KEY POINTS

•There is no clear consensus regarding the primary imaging modality for the evaluation of LHBT disorders. •Conventional MRI and MR arthrography are highly specific in diagnosing complete tears of the LHBT. •Diagnosis of partial tears/tendinosis of the LHBT on conventional MRI and MR arthrography remains a diagnostic challenge.

Interdisciplinary consensus statements on imaging of DRUJ instability and TFCC injuries

OBJECTIVES

The purpose of this agreement was to establish evidence-based consensus statements on imaging of distal radioulnar joint (DRUJ) instability and triangular fibrocartilage complex (TFCC) injuries by an expert group using the Delphi technique.

METHODS

Nineteen hand surgeons developed a preliminary list of questions on DRUJ instability and TFCC injuries. Radiologists created statements based on the literature and the authors' clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panelists consisted of twenty-seven musculoskeletal radiologists. The panelists scored their degree of agreement to each statement on an 11-item numeric scale. Scores of "0," "5," and "10" reflected complete disagreement, indeterminate agreement, and complete agreement, respectively. Group consensus was defined as a score of "8" or higher for 80% or more of the panelists.

RESULTS

Three of fourteen statements achieved group consensus in the first Delphi round and ten statements achieved group consensus in the second Delphi round. The third and final Delphi round was limited to the one question that did not achieve group consensus in the previous rounds.

CONCLUSIONS

Delphi-based agreements suggest that CT with static axial slices in neutral rotation, pronation, and supination is the most useful and accurate imaging technique for the work-up of DRUJ instability. MRI is the most valuable technique in the diagnosis of TFCC lesions. The main indication for MR arthrography and CT arthrography are Palmer 1B foveal lesions of the TFCC.

CLINICAL RELEVANCE STATEMENT

MRI is the method of choice for assessing TFCC lesions, with higher accuracy for central than peripheral abnormalities. The main indication for MR arthrography is the evaluation of TFCC foveal insertion lesions and peripheral non-Palmer injuries.

KEY POINTS

• Conventional radiography should be the initial imaging technique in the assessment of DRUJ instability. CT with static axial slices in neutral rotation, pronation, and supination is the most accurate method for evaluating DRUJ instability. • MRI is the most useful technique in diagnosing soft-tissue injuries causing DRUJ instability, especially TFCC lesions. • The main indications for MR arthrography and CT arthrography are foveal lesions of the TFCC.

Ultra-low-dose computed tomography for torsion measurements of the lower extremities in children and adolescents

BACKGROUND

Quantifying femoral and tibial torsion is crucial in the preoperative planning for derotation surgery in children and adolescents. The use of an ultra-low-dose computed tomography (CT) protocol might be possible for modern CT scanners and suitable for reliable torsion measurements even though the bones are not completely ossified.

METHODS

This is a retrospective review of 77 children/adolescents (mean age 12.7 years) who underwent a lower extremity CT for torsion measurements on a 64-slice scanner. A stepwise dose reduction (70%, 50%, 30% of the original dose) was simulated. Torsion measurements were performed on all image datasets, and image noise, interrater agreement and subjective image quality were evaluated. Effective radiation dose of each original scan was estimated. As proof of concept, 24 children were scanned with an ultra-low-dose protocol, adapted from the 30% dose simulation, and the intra-class correlation coefficient (ICC) was determined. Ethics approval and informed consent were given.

RESULTS

Torsion measurements at the simulated 30% dose level had equivalent interrater agreement compared to the 100% dose level (ICC ≥ 0.99 for all locations and dose levels). Image quality of almost all datasets was rated excellent, regardless of dose. The mean sum of the effective dose of the total torsion measurement was reduced by simulation from 0.460/0.490 mSv (boys/girls) at 100% dose to 0.138/0.147 mSv at 30%. The ICC of the proof-of-concept group was as good as that of the simulated 30% dose level.

CONCLUSION

Pediatric torsion measurements of the lower extremities can be performed using an ultra-low-dose protocol without compromising diagnostic confidence.

Comparison of temporal evolution of computed tomography imaging features in COVID-19 and influenza infections in a multicenter cohort study

Purpose

To compare temporal evolution of imaging features of coronavirus disease 2019 (COVID-19) and influenza in computed tomography and evaluate their predictive value for distinction.

Methods

In this retrospective, multicenter study 179 CT examinations of 52 COVID-19 and 44 influenza critically ill patients were included. Lung involvement, main pattern (ground glass opacity, crazy paving, consolidation) and additional lung and chest findings were evaluated by two independent observers. Additional findings and clinical data were compared patient-wise. A decision tree analysis was performed to identify imaging features with predictive value in distinguishing both entities.

Results

In contrast to influenza patients, lung involvement remains high in COVID-19 patients > 14 days after the diagnosis. The predominant pattern in COVID-19 evolves from ground glass at the beginning to consolidation in later disease. In influenza there is more consolidation at the beginning and overall less ground glass opacity (p = 0.002). Decision tree analysis yielded the following: Earlier in disease course, pleural effusion is a typical feature of influenza (p = 0.007) whereas ground glass opacities indicate COVID-19 (p = 0.04). In later disease, particularly more lung involvement (p < 0.001), but also less pleural (p = 0.005) and pericardial (p = 0.003) effusion favor COVID-19 over influenza. Regardless of time point, less lung involvement (p < 0.001), tree-in-bud (p = 0.002) and pericardial effusion (p = 0.01) make influenza more likely than COVID-19.

Conclusions

This study identified differences in temporal evolution of imaging features between COVID-19 and influenza. These findings may help to distinguish both diseases in critically ill patients when laboratory findings are delayed or inconclusive.

•

Decision tree analysis helps to distinguish COVID-19 and Influenza.

•

Pleural effusion is a typical feature of influenza in early disease.

•

Ground glass opacities indicate COVID-19 in early disease.

•

Lung involvement remains high in COVID-19 patients > 14 days after the diagnosis.

•

Pleural and pericardial effusion favor influenza over COVID-19 in later disease.

Retrospective evaluation of routine in-hospital observation in 433 patients after CT-guided biopsies

BACKGROUND

After computed tomography (CT)-guided interventions, routine in-hospital observation is recommended by the Cardiovascular and Interventional Radiological Society of Europe.

PURPOSE

To evaluate the frequency of delayed major complications or hospitalizations after CT-guided biopsies in patients with initially no or minor complications and to assess whether routine in-hospital observation is justified.

MATERIAL AND METHODS

This retrospective study included 433 outpatients after CT-guided biopsy of the thoracic (n = 176), abdominal (n = 129), or musculoskeletal (n = 128) region with subsequent in-hospital observation. Complications were graded according to the current Society of Interventional Radiology recommendations and grouped into minor or major. A complication that occurred during in-hospital observation was defined as delayed complication. A delayed major complication was a newly developed major complication or a progression from an initially minor to a major complication. Hospitalization frequencies were evaluated similarly. Occurrence, 95% confidence intervals (CI), and P values for significant differences between the three organ groups were calculated. If delayed major complications were more frequent than 1%, routine in-hospital observation was considered justified.

RESULTS

Delayed, major complication frequencies were: thoracic, 8.2% (95% CI 4.6-13.4); abdominal, 0.0% (95% CI 0.0-2.9); and musculoskeletal, 0.0% (95% CI 0.0-2.9) (P < 0.001). Delayed hospitalization frequencies were: thoracic, 8.8% (95% CI 5.0-14.2); abdominal, 1.6% (95% CI 0.2-5.6); and musculoskeletal, 0.0% (95% CI 0.0-2.9) (P < 0.001).

CONCLUSION

After thoracic interventions, routine observation is considered justified for patient safety whereas routine observation may be omitted after musculoskeletal interventions. In the abdominal group, no delayed complications were observed, but delayed hospitalization occurred. Thus, in-hospital observation could be justified in a safe patient environment, but remains an individual decision.

Age dependent prevalence of the supraacetabular fossa in children, adolescents and young adults

OBJECTIVES

The supraacetabular fossa (SAF) is an anatomical variant of the acetabular roof which may mimic a cartilage defect. Two different subtypes have been described: type 1 fluid-filled and type 2 cartilage-filled. The adult prevalence of SAF was reported between 10.5 and 12.6%. We aimed to determine SAF prevalence in a pediatric and young adult population and examine the potential remodeling of the subtypes over time.

METHODS

A retrospective search of the institutional database for hip MRI of participants aged 4-25 years was carried out between 2010 and 2020. A total of 401 eligible MRIs of 323 participants were analyzed by two readers. The documented features were: existence of SAF, definition of subtype and measurements of the SAF in three dimensions. Logistic regression models were calculated to estimate the influence of age on the presence of SAF.

RESULTS

Out of 323, 115 (35,6%) participants demonstrated a supraacetabular fossa. 63 (19.5%) participants presented subtype 1 and 51 (15.8%) type 2; one participant had both. The predicted probability for SAF increases until the age of 14, beyond 14 years, the combined predicted probability for both subtypes decreased again. In contrast to SAF type 1, SAF type 2 was more prevalent with older age. The size of the SAF decreased with aging.

CONCLUSION

The supraacetabular fossa is most frequent in adolescents. With higher age, the prevalence and the size of the SAF decreased. This data supports the theory that the SAF is a developmental variant.

Clinical and Imaging Features of COVID-19-Associated Pulmonary Aspergillosis

Background: COVID-19 superinfection by Aspergillus (COVID-19-associated aspergillosis, CAPA) is increasingly observed due to increased awareness and use of corticosteroids. The aim of this study is to compare clinical and imaging features between COVID-19 patients with and without associated pulmonary aspergillosis. Material and Methods: In this case–control study, hospitalized patients between March 2020 and March 2021 were evaluated. Two observers independently compared 105 chest CTs of 52 COVID-19 patients without pulmonary aspergillosis to 40 chest CTs of 13 CAPA patients. The following features were evaluated: lung involvement, predominant main pattern (ground glass opacity, crazy paving, consolidation) and additional lung and chest findings. Chronological changes in the abnormal extent upon CT and chronological changes in the main patterns were compared with mixed models. Patient-wise comparisons of additional features and demographic and clinical data were performed using Student’s t-test, Chi-squared test, Fisher’s exact tests and Wilcoxon rank-sum tests. Results: Compared to COVID-19 patients without pulmonary aspergillosis, CAPA patients were older (mean age (±SD): 70.3 (±7.8) versus 63.5 (±9.5) years (p = 0.01). The time-dependent evolution rates for consolidation (p = 0.02) and ground glass (p = 0.006) differed. In early COVID-19 disease, consolidation was associated with CAPA, whereas ground glass was less common. Chronological changes in the abnormal extent upon CT did not differ (p = 0.29). Regardless of the time point, bronchial wall thickening was observed more frequently in CAPA patients (p = 0.03). Conclusions: CAPA patients showed a tendency for consolidation in early COVID-19 disease. Bronchial wall thickening and higher patient age were associated with CAPA. The overall lung involvement was similar between both groups.

Short tau inversion recovery (STIR) after intravenous contrast agent administration obscures bone marrow edema-like signal on forefoot MRI

OBJECTIVE

Short tau or short TI inversion recovery (STIR) MRI sequences are considered a robust fat suppression technique. However, STIR also suppresses signals from other tissues with similar T1 relaxation times. This study investigates the in vivo effect of intravenous gadolinium-based T1-shortening contrast agent on STIR signal.

MATERIALS AND METHODS

Institutional board approval and informed consent was obtained. MRI examinations (1.5-T or 3-T) of 31 prospectively included patients were analyzed by two readers. Signal intensity of degenerative bone marrow edema-like signal at the Lisfranc joint on precontrast STIR images and on STIR images acquired after intravenous contrast agent administration (gadoteric acid, gadolinium: 0.5 mmol/ml, 15 ml) was measured. The medial cuneiform bone without observable bone marrow edema-like signal was considered a healthy tissue and served as a reference. Relative changes in signal intensity between precontrast and postcontrast images were calculated for the two tissues. Wilcoxon signed-rank test served for statistical analyses.

RESULTS

In bone marrow edema-like signal, both readers observed a median signal change of -35% (interquartile range (IQR) 24) and -34% (IQR 21), respectively, on postcontrast STIR images compared to precontrast STIR. In healthy tissue, the signal remained constant on postcontrast STIR images (median change -2%, IQR 15, and 0%, IQR 17) respectively. For both readers, postcontrast signal change in bone marrow edema-like signal differed from that in healthy tissue (p < 0.001).

CONCLUSION

Intravenous gadolinium-based contrast agent causes a significant reduction of signal intensity in bone marrow edema-like signal on routine STIR images. Thus, pathological MRI findings may be obscured.

Interdisciplinary consensus statements on imaging of scapholunate joint instability

Objectives

The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique.

Methods

Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors’ clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of ‘0’, ‘5’ and ‘10’ reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of ‘8’ or higher for 80% or more of the panellists.

Results

Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available.

Conclusions

Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability.

Key Points

• Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability.

• Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability.

• Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 3: imaging techniques

OBJECTIVES

Imaging diagnosis of femoroacetabular impingement (FAI) remains controversial due to a lack of high-level evidence, leading to significant variability in patient management. Optimizing protocols and technical details is essential in FAI imaging, although challenging in clinical practice. The purpose of this agreement is to establish expert-based statements on FAI imaging, using formal consensus techniques driven by relevant literature review. Recommendations on the selection and use of imaging techniques for FAI assessment, as well as guidance on relevant radiographic and MRI classifications, are provided.

METHODS

The Delphi method was used to assess agreement and derive consensus among 30 panel members (musculoskeletal radiologists and orthopedic surgeons). Forty-four questions were agreed on and classified into five major topics and recent relevant literature was circulated, in order to produce answering statements. The level of evidence was assessed for all statements and panel members scored their level of agreement with each statement during 4 Delphi rounds. Either "group consensus," "group agreement," or "no agreement" was achieved.

RESULTS

Forty-seven statements were generated and group consensus was reached for 45. Twenty-two statements pertaining to "Imaging techniques" were generated. Eight statements on "Radiographic assessment" and 12 statements on "MRI evaluation" gained consensus. No agreement was reached for the 2 "Ultrasound" related statements.

CONCLUSION

The first international consensus on FAI imaging was developed. Researchers and clinicians working with FAI and hip-related pain may use these recommendations to guide, develop, and implement comprehensive, evidence-based imaging protocols and classifications.

KEY POINTS

• Radiographic evaluation is recommended for the initial assessment of FAI, while MRI with a dedicated protocol is the gold standard imaging technique for the comprehensive evaluation of this condition. • The MRI protocol for FAI evaluation should include unilateral small FOV with radial imaging, femoral torsion assessment, and a fluid sensitive sequence covering the whole pelvis. • The definite role of other imaging methods in FAI, such as ultrasound or CT, is still not well defined.

The Lisbon Agreement on femoroacetabular impingement imaging-part 2: general issues, parameters, and reporting

OBJECTIVES

Imaging assessment for the clinical management of femoroacetabular impingement (FAI) is controversial because of a paucity of evidence-based guidance and notable variability among practitioners. Hence, expert consensus is needed because standardised imaging assessment is critical for clinical practice and research. We aimed to establish expert-based statements on FAI imaging by using formal methods of consensus building.

METHODS

The Delphi method was used to formally derive consensus among 30 panel members from 13 countries. Forty-four questions were agreed upon, and relevant seminal literature was circulated and classified in major topics to produce answering statements. The level of evidence was noted for all statements, and panel members were asked to score their level of agreement (0-10). This is the second part of a three-part consensus series and focuses on 'General issues' and 'Parameters and reporting'.

RESULTS

Forty-seven statements were generated and group consensus was reached for 45. Twenty-five statements pertaining to 'General issues' (9 addressing diagnosis, differential diagnosis, and postoperative imaging) and 'Parameters and reporting' (16 addressing femoral/acetabular parameters) were produced.

CONCLUSIONS

The available evidence was reviewed critically, recommended criteria for diagnostic imaging highlighted, and the roles/values of different imaging parameters assessed. Radiographic evaluation (AP pelvis and a Dunn 45° view) is the cornerstone of hip-imaging assessment and the minimum imaging study that should be performed when evaluating adult patients for FAI. In most cases, cross-sectional imaging is warranted because MRI is the 'gold standard' imaging modality for the comprehensive evaluation, differential diagnosis assessment, and FAI surgical planning.

KEY POINTS

• Diagnostic imaging for FAI is not standardised due to scarce evidence-based guidance on which imaging modalities and diagnostic criteria/parameters should be used. • Radiographic evaluation is the cornerstone of hip assessment and the minimum study that should be performed when assessing suspected FAI. Cross-sectional imaging is justified in most cases because MRI is the 'gold standard' modality for comprehensive FAI evaluation. • For acetabular morphology, coverage (Wiberg's angle and acetabular index) and version (crossover, posterior wall, and ischial spine signs) should be assessed routinely. On the femoral side, the head-neck junction morphology (α° and offset), neck morphology (NSA), and torsion should be assessed.

Subspecialized radiological reporting reduces radiology report turnaround time

Objectives

The objective of this study was to compare the radiology report turnaround time (RTAT) between decentralized/modality-based and centralized/subspecialized radiological reporting at a multi-center radiology enterprise.

Methods

RTAT values for MRI, CT, and conventional radiography were compared between decentralized/modality-based (04 September 2017–22 December 2017) and centralized/subspecialized radiology (03 September 2018–21 December 2018) reporting grouped into three subspecializations (body radiology, musculoskeletal radiology, and neuroradiology) at eleven sites of a multi-center radiology enterprise. For the objective of this investigation, hospitals were defined as major and minor hospitals. The Mann-Whitney U test served for statistical analyses.

Results

Change of reporting system from decentralized/modality-based to centralized/subspecialized radiology resulted overall in a significant decrease of the RTAT: from 82 to 77 min for the first signature (p < 0.001), and 119 to 107 min and 295 to 238 min for the second signature (p < 0.001). Subgroup analyses demonstrate a significant decrease of the RTAT for MRI reports (e.g., second signature RTAT, 1051 to 401 min; p < 0.001) and conventional radiographs (e. g., second signature RTAT, 278 to 171 min; p < 0.001). The RTAT at major hospitals decreased from 288 to 245 min (second signature; p < 0.001) while the corresponding RTAT of minor hospitals decreased more remarkably, from 300 to 198 min (p < 0.001). However, the results were heterogenous; in some analyses, the RTAT even increased. The effect size analyses represent small effects.

Conclusions

Change of reporting system from decentralized/modality-based to centralized/subspecialized radiology was associated with a significant decreased RTAT. Specifically, the RTAT for MRI reports and conventional radiographs was significantly reduced. A pronounced RTAT decrease was observed at minor hospitals.

Correction to: The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 1: overview

The original version of this article, published on 14 May 2020, unfortunately contained a mistake.

The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 1: overview

OBJECTIVES

Imaging assessment for the clinical management of femoroacetabular impingement (FAI) syndrome remains controversial because of a paucity of evidence-based guidance and notable variability in clinical practice, ultimately requiring expert consensus. The purpose of this agreement is to establish expert-based statements on FAI imaging, using formal techniques of consensus building.

METHODS

A validated Delphi method and peer-reviewed literature were used to formally derive consensus among 30 panel members (21 musculoskeletal radiologists and 9 orthopaedic surgeons) from 13 countries. Forty-four questions were agreed on, and recent relevant seminal literature was circulated and classified in five major topics ('General issues', 'Parameters and reporting', 'Radiographic assessment', 'MRI' and 'Ultrasound') in order to produce answering statements. The level of evidence was noted for all statements, and panel members were asked to score their level of agreement with each statement (0 to 10) during iterative rounds. Either 'consensus', 'agreement' or 'no agreement' was achieved.

RESULTS

Forty-seven statements were generated, and group consensus was reached for 45 (95.7%). Seventeen of these statements were selected as most important for dissemination in advance. There was no agreement for the two statements pertaining to 'Ultrasound'.

CONCLUSION

Radiographic evaluation is the cornerstone of hip evaluation. An anteroposterior pelvis radiograph and a Dunn 45° view are recommended for the initial assessment of FAI although MRI with a dedicated protocol is the gold standard imaging technique in this setting. The resulting consensus can serve as a tool to reduce variability in clinical practices and guide further research for the clinical management of FAI.

KEY POINTS

• FAI imaging literature is extensive although often of low level of evidence. • Radiographic evaluation with a reproducible technique is the cornerstone of hip imaging assessment. • MRI with a dedicated protocol is the gold standard imaging technique for FAI assessment.

Postoperative Imaging after Impingement Surgery

In addition to the patient's medical history and clinical evaluation, conventional radiographs and magnetic resonance imaging (MRI) are important tools to indicate appropriate conservative treatment or even revision surgery in patients with symptoms after surgical management of femoroacetabular impingement (FAI). We present an overview of current evidence in postoperative imaging after impingement surgery. Undercorrection of the underlying osseous FAI configuration is the most frequent indication for revision surgery within the first 2 years after index FAI surgery. Femoral neck fractures, iatrogenic chondral injuries, early conversion to total hip arthroplasty, loose bodies, and heterotopic ossifications are rare but typical early complications after surgical treatment of FAI. Abnormal MRI findings after FAI surgery such as intra-articular adhesions, labral tears, cartilage defects, and anterior capsular defects are common findings in both asymptomatic and symptomatic postoperative patients. Avascular necrosis of the femoral head is an extremely rare complication after surgical treatment of FAI.

Articular cartilage and labral lesions of the glenohumeral joint: diagnostic performance of 3D water-excitation true FISP MR arthrography

OBJECTIVE

To evaluate the diagnostic performance of MR arthrography in the detection of articular cartilage and labral lesions of the glenohumeral joint using a transverse 3D water-excitation true fast imaging with steady-state precession (FISP) sequence.

MATERIALS AND METHODS

Seventy-five shoulders were included retrospectively. Shoulder arthroscopy was performed within 6 months of MR arthrography. MR images were evaluated separately by two radiologists. They were blinded to clinical and arthroscopic information. Arthroscopy served as the reference standard.

RESULTS

For the detection of humeral cartilage lesions, sensitivities and specificities were 86% (12/14)/89% (50/56) for observer 1 and 93%/86% for observer 2) for the transverse true FISP sequence and 64%/86% (50%/82% for observer 2) for the coronal intermediate-weighted spin-echo images. The corresponding values for the glenoidal cartilage were 60% (6/10)/88% (51/58) (80%/76% for observer 2) and 70%/86% (60%/74% for observer 2) respectively. For the detection of abnormalities of the anterior labrum (only assessed on true FISP images) the values were 94% (15/16)/84% (36/43) (88%/79% for observer 2). The corresponding values for the posterior labrum were 67% (8/12)/77% (36/47) (observer 2: 25%/74%). The kappa values for the grading of the humeral and glenoidal cartilage lesions were 0.81 and 0.55 for true FISP images compared with 0.49 and 0.43 for intermediate-weighted fast spin-echo images. Kappa values for true FISP evaluation of the anterior and posterior part of the labrum were 0.81 and 0.70.

CONCLUSION

Transverse 3D true FISP MR arthrography images are useful for the difficult diagnosis of glenohumeral cartilage lesions and suitable for detecting labral abnormalities.

Detection and follow-up of homonymous visual field defects - perimetric essentials for evaluation of spontaneous recovery

Clinical detection and follow-up of homonymous visual field defects require appropriate perimetric procedures: since postgeniculate lesions are usually characterised by absolute scotomata, time consuming threshold methods can be replaced by supraliminal strategies with comparatively high stimulus densities. Compared with equidistant rectangular grids, a centripetal stimulus condensation represents the physiological conditions more adequately and thus is more effective. It allows one to differentiate central changes of the visual field, like macular sparing or splitting, which also interfere with reading performance. This procedure requires test points to be located to either side of the vertical meridian, rather than directly on it. Multimodal assessment of visual subfunctions (using static, kinetic or colour test points, random dot patterns or optokinetic stimulation) specifies the effect of the lesion in different channels or regions of the visual pathways. Automation of perimetric procedures and continuous monitoring of fixation are important tools, enhancing the quality of examination and follow-up. The above mentioned psychophysical techniques for detection of functional defects and documentation of eventual recovery, as well as matching neuroimaging findings, are demonstrated by illustrative cases.

[Comparison of local differential luminance sensitivity (dls) between Oculus Twinfield Perimeter and Humphrey Field Analyzer 630 (HFA I) in normal volunteers of varying ages]

PURPOSE

Purpose of this study was to compare age-corrected normal values of differential luminance sensitivity (dls) of the Oculus Twinfield Perimeter with those of the Humphrey Field Analyzer 630 (HFA I). Furthermore, naso-temporal and superior-inferior asymmetries in the central visual field were analyzed.

METHODS

72 ophthalmologically normal volunteers, 12 per decade, were examined with both perimeters using a 4-2 dB bracketing strategy with two reversals for threshold estimation. A biometric model, which fits a hill of vision to the data, was developed. The age-related hills, created by the model, were compared between the instruments and analyzed for asymmetries.

RESULTS

The normal dls values for the Twinfield perimeter were about 1.5 dB above those of the HFA I. The shape of the hill in regard to slope in corresponding locations did not differ substantially. The decline of local differential luminance sensitivity showed a nonlinear correlation to age: it remained almost constant up to the 4th decade, with a steeper decline beyond that age. A naso-temporal as well as a superior-inferior asymmetry was found. Along the vertical meridian, the slope of the hill was steeper in the superior part than in the inferior. At an excentricity of 20 degrees we found a superior-inferior difference of 2.1 dB for the HFA and of 1.8 dB for the Twinfield perimeter benefitting the inferior meridian. Along the horizontal meridian there was a distinct difference in regard to the shape of the hill. The sensitivity was greater in the temporal half of the visual field than in the nasal. At an excentricity of 30 degrees, the difference was about 2.75 dB for the HFA and 2.5 dB for the Twinfield perimeter. These asymmetries seem to appear in all age groups. Unfortunately, the exact influence of age on the appearing asymmetries cannot be quantified by the used model.

CONCLUSION

The normal dls values benefit the Twinfield for about 1.5 dB compared to the HFA. There seems to be a critical age of about 40 - 50 years, beyond which a decline of dls becomes manifest.

Reaction time in automated kinetic perimetry: effects of stimulus luminance, eccentricity, and movement direction

PURPOSE

To determine the effects of stimulus eccentricity and luminance level on the reaction time (RT) of young normal volunteers during automated kinetic campimetry.

METHODS

We used a specially designed video-campimetric device equipped with a continuous infrared (IR) pupillographic fixation control (Tübingen Computer Campimeter) and recorded reaction times upon presenting horizontally moving small circular stimuli (size 26'; constant angular velocity 2 degrees /s) starting at 16 locations within the central 30 degrees -radius of the visual field. Two different levels of stimulus luminance were used (41.6 cd/m(2) and 110 cd/m(2)), while background luminance was 10 cd/m(2). Each stimulus was presented a total of six times in a randomized order. Subjects were 12 healthy young individuals (aged 21-30 years) with normal ophthalmic examinations. An analysis of variance (ANOVA) was performed on the data.

RESULTS

RTs showed considerable inter- and intra-individual variation with individual least squares means (LSM, fitted values of a linear model) ranging from 305 to 454 ms, and residual standard deviation (R.S.D.) 66 ms. Reaction times did not differ significantly as a function of stimulus direction (P>0.6). Higher luminance levels produced significantly reduced reaction times for all stimulus locations and directions (mean reduction: 16 ms; P<0.0001). Reaction times increased with increasing eccentricity, in the mean by 1.8 ms per degree of visual angle, from 365+/-4 ms (S.E.M.) foveally, to 407+/-2 ms at 30 degrees eccentricity; (P<0.0001).

CONCLUSIONS

Automated kinetic perimetry should be designed to cope with significant, variable interindividual response characteristics. Other stimulus related factors, such as eccentricity or luminance level, have a significant but comparatively small effect on reaction time within the central 30 degrees -radius visual field in healthy young individuals.

Evaluation of glaucomatous visual field loss with locally condensed grids using fundus-oriented perimetry (FOP)

PURPOSE

We compared detection rates of glaucomatous visual field defects (VFDs) between a conventional rectangular stimulus grid and locally condensed test point arrangements in morphologically suspicious regions.

METHODS

Humphrey Field Analyzer model 630 (HFA I, program 30-2 with a rectangular 6 degrees x 6 degrees grid) was used as the conventional perimetric method. Individual local test-point condensation was realized by fundus-oriented perimetry (FOP) on the Tuebingen Computer Campimeter (TCC).

RESULTS

Of a total of 66 glaucoma patients, or suspected sufferers, 23 showed normal findings and 27 showed pathological findings with both methods. In 15 cases we found normal visual fields in HFA 30-2, whereas FOP revealed early glaucomatous functional damage. Only one case showed pathological HFA results, while FOP was normal. Detection rates of VFDs significantly differed between the two methods (p < 0.001; sign test).

CONCLUSIONS

FOP, using individually condensed test grids, significantly increases detection rates of glaucomatous VFDs in morphologically suspicuous areas compared with a conventional HFA 30-2 technique using equidistant rectangular (6 degrees x 6 degrees) test point arrangements.

Scaling exponent predicts defibrillation success for out-of-hospital ventricular fibrillation cardiac arrest

BACKGROUND

-Defibrillator shocks often fail to terminate ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OOHCA), and repeated failed shocks can worsen the subsequent response to therapy. Because the VF waveform changes with increasing duration of VF, it is possible that ECG analyses could estimate the preshock likelihood of defibrillation success. This study examined whether an amplitude-independent measure of preshock VF waveform morphology predicts outcome after defibrillation. Methods and Results-Clinical data and ECG recordings from an automated external defibrillator were obtained for 75 subjects with OOHCA in a suburban community with police first responders and a paramedic-based emergency medical system. An estimate of the fractal self-similarity dimension, the scaling exponent, was calculated off-line for the VF waveform preceding shocks. Success of the first shock was determined from the recordings. Return of pulses and survival were determined by chart review. The first shock resulted in an organized rhythm in 43% of cases, and 17% of cases survived to hospital discharge. A lower mean value of the scaling exponent was observed for cases in which the first defibrillation resulted in an organized rhythm (P:=0.004), for cases with return of pulses (P:=0.049), and for cases surviving to hospital discharge (P:<0.001). Receiver operator curves revealed the utility of the scaling exponent for predicting the probability of restoring an organized rhythm (area under the curve=0.70) and of survival (area under the curve=0.84).

CONCLUSIONS

-The VF waveform in OOHCA can be quantified with the scaling exponent, which predicts the probability of first-shock defibrillation and survival to hospital discharge.

An explicit no response instead of time-out in automated visual-field testing

BACKGROUND

To evaluate the effect of response-acquisition technique on psychometric performance in visual-field testing, the conventional one-button yes/time-out method was compared with a two-button yes/no method for responding whether or not the stimulus was detected. There are a number of situations in which the single-button technique leads to ambiguous results. In this study, we thus expected the yes/no method to reduce tendencies towards habituation and automatic responding. Our hypothesis was that the two-button technique could reduce the rate of erroneous responses.

METHODS

Luminance-difference sensitivity for bright stimuli (32') on a photopic background was evaluated at 26 locations within the central visual field (30 degrees) using a specially equalised video display unit and a modified 4/2-dB staircase strategy (six reversals, maximum-likelihood threshold estimation). Sixty-one ophthalmologically normal subjects (aged 20-30 years) were examined twice with each method.

RESULTS

Mean sensitivities with the two-button yes/no method were found to be, on average, 0.13 dB above those measured with the one-button yes/time-out technique--a difference without clinical relevance. Within-subject variability did not differ between the two methods. However, the less intuitive two-button yes/no method had a slightly higher number of false responses in catch trials.

CONCLUSION

Compared to the conventional one-button yes/time-out method, the two-button yes/no method in normal young subjects thus showed little difference in mean sensitivities and equivalent within-subject variabilities. Concerning our initial hypothesis, the yes/no method is of somewhat higher complexity and is not able to reduce the rate of erroneous responses. The one-button yes/time-out method fared a little better in error rate. In summary, the yes/no method is an alternative and additional possibility of response acquisition in visual-field testing, which is worthy of being tested in a clinical study with elderly subjects.

[Evaluation of extensive visual field defects with computer-assisted kinetic perimetry]

BACKGROUND

Conventional kinetic perimetry is of especial use in case of advanced scotoma. However, examiner dependency is a major drawback. Purpose of this study was to evaluate the clinical feasibility and intraindividual scatter of computer-assisted kinetic perimetry in monitoring advanced visual field defects of various origins.

METHODS

Examinations were carried out with the Tuebingen Computer Campimeter (background lumincance 10 cd/m2). In an initial session, the localization of the scotoma border is estimated with conventional manual kinetic perimetry. In the subsequent computer assisted kinetic mode, an individually adjusted set of vectors is designed. Each vector crosses the manually assessed visual field defect border almost perpendicularly, starting approximately 3 degrees within the scotoma. Each individual set of vectors can be stored and recalled for follow-up. Stimuli move along these vectors with identical characteristics as in manual kinetic perimetry. Stimulus presentations are repeated six times in a randomized order. Patients' responses are recorded and additionally corrected for mean individual reaction time. A "local kinetic threshold" (mean) and a related parameter for dispersion (standard deviation) are assessed.

RESULTS

Four subjects with advanced visual field loss of various origin (retinitis pigmentosa, vigabatrin-associated visual field defect, glaucomatous nerve fibre layer defect, and postgeniculate visual pathway defect) participated in this study. Maximal difference between manual-kinetic and automated kinetic thresholds reaches from 1.7 degrees to 5 degrees. Local scatter (standard deviation) of kinetic threshold, assessed by computer-assisted perimetry, varies between 0.1 degree and 3.0 degrees.

CONCLUSION

Computer assisted kinetic perimetry is a new, useful, examiner-independent, reliable method for effective evaluation and monitoring of advanced visual field loss.

Angioscotoma detection with fundus-oriented perimetry. A study with dark and bright stimuli of different sizes

Fundus-oriented perimetry (FOP) was used to evaluate the effectiveness of different-sized bright and dark stimuli in detecting and quantitatively measuring angioscotoma. The foveolas and optic disks of digitized fundus images were aligned with their psychophysical counterparts to construct individual grids of perimetric stimuli. Each grid included a linear set of test point locations crossing a retinal vessel. Angioscotomas immediately became visible in nine of 13 healthy normal volunteers tested with FOP. Additional mathematical processing of local loss of differential light sensitivity (dls) disclosed an angioscotoma for at least one stimulus condition in all persons tested. The angioscomas were usually deeper for small (12) targets than for large (32') ones. On the other hand, the overall noise at dls thresholds was generally higher for small than for large stimuli regardless of whether the stimuli were bright or dark. No noteworthy differences were found in detection rates or signal-to-noise ratios under different stimulus conditions (dark/bright/small/large). FOP permits the individual arrangement of stimuli for specific morphological conditions and is thus capable of detecting even minute visual field defects such as angioscotomas.

Lesion location influences perception of homonymous scotomata during flickering random dot pattern stimulation

An attempt was made to clarify whether the site of postchiasmal lesions affects subjective perception of homonymous visual field defects during stimulation with flickering random dot patterns (white noise-field). Out of 56 patients with homonymous hemianopia, 38 (68%) perceived scotomata in this situation, but 18 (32%) discerned none at all. Neuroradiologic superposition of cerebral lesions detected by computed tomography (CT) or magnetic resonance imaging (MRI) showed that nearly all patients who perceived their scotomata had lesions involving the primary visual cortex or the perigeniculate region, whereas those who received no scotoma had lesions centered within the optic radiation. Functional MRI of six normal subjects during stimulation with flickering random dot patterns indicated predominant activation of the primary visual cortex. Since noise-field defects were most frequently perceived by patients whose lesion involved the primary visual cortex, it appears that the sensitivity of noise-field campimetry depends on the site of damage in the visual pathway. The explanation for this may be that damage to long-range horizontal connections impairs filling-in processes.

Technetium-99m-MAG3 scintigraphy in acute renal failure after transplantation: a marker of viability and prognosis

This study assessed 99mTc-mercaptoacetyltriglycine (MAG3) for determination of renal transplant prognosis for recovery in patients with early postoperative dysfunction. The postulate tested was that good tracer extraction may imply high likelihood of recovery, while poor extraction may confer a poor prognosis.

METHODS

A 2-min image acquired 1 min after MAG3 administration, named a cortical uptake phase (CUP) image, was visually analyzed according to standardized semiquantitative guidelines. Interpretation was expressed in tubular injury severity scores (TISS) that ranged from 1 (a normally functioning renal transplant) to 6 (a photopenic defect in place of renal transplant).

RESULTS

The study analyzed 64 patients (35 men, 29 women, age 45.9 +/- 14 yr). All five patients with TISS of 6 or 5 lost the transplant. Only 1 of 10 patients with TISS of 4 lost the transplant. All patients with TISS of less than 4 recovered renal transplant function.

CONCLUSION

This study suggests that MAG3 scan (the CUP image specifically) is an accurate prognosticator in patients with early postoperative renal transplant dysfunction. Reproduction of these results in a larger population and other institutions is necessary before clinical implementation of this methodology.

[Fundus-oriented perimetry. Evaluation of a new visual field examination method for detecting angioscotoma]

BACKGROUND

Conventional automated perimeters usually work with a given set of grids and thus are normally not adapted to individual conditions. This fact restricts efficiency of this method not only for any single examination but also for follow-up studies.

MATERIALS AND METHODS

A new method (patent pending) is introduced which superimposes an individual perimetric grid--corrected in respect to orientation, position and size--onto a patient's fundus image. A recently developed software realizes this procedure in a comfortable manner: the digitized fundus image is loaded into the computer by e.g. photo-CD or disc, depicted on a control monitor and mirrored if necessary. Assuming a central fixation, the foveola is translationally shifted to the center of the perimetric grid by the help of a crosshair. The blind spot which has been previously determined with kinetic perimetry is then superimposed onto the optic disc of the fundus image using a rotation and zoom function. In this way, it is possible to adapt the perimetric grid directly to the underlying individual fundus findings: thus, stimuli can be spatially concentrated or more frequently tested in special regions of interest. Additionally, test points can be dragged away from delicate positions to avoid artifacts. Examinations were carried out on a high resolution colour VDU of the Tübingen Electronic Campimeter (TCC). Alternatively, suited bowl perimeters can be used.

RESULTS

In order to test the precision of the superimposing procedure, fundus oriented perimetry was performed to detect angioscotomata in 13 ophthalmologically normal subjects. Using dark stimuli (12'), visual field defects in the expected region, caused by retinal vessels, could be detected in 7 cases (= 54%). The resulting attenuation of differential light sensitivity in this circumscribed region was up to 12 dB.

CONCLUSIONS

By means of a morphologically adapted, individual arrangement of stimulus locations fundus-oriented perimetry enables detection of even minute (angio-) scotomata.