Blinded-Read of Bone Scintigraphy: The Impact on Diagnosis and Healing Time for Stress Injuries With Emphasis on the Foot

Diagnostic Evaluation of Stress Injuries of the Hip Using MR Imaging

Understanding the complex anatomy and development of the hip is crucial for diagnosing and categorizing femoral neck stress fractures in athletes. These fractures result from repetitive mechanical loading, affecting trabecular structure. Various risk factors include hormonal imbalances and hip geometry. Although radiographs are initial diagnostic tools, MR imaging is the gold standard, distinguishing between stress reactions and fractures. Treatment involves surgical fixation, whereas nonsurgical methods for less severe fractures have good results. Overall, comprehensive knowledge is essential for effective diagnosis and correct early management of femoral neck stress fractures.

ACR Appropriateness Criteria® Stress (Fatigue-Insufficiency) Fracture Including Sacrum Excluding Other Vertebrae: 2024 Update

Stress fractures, including both fatigue and insufficiency types, are frequently encountered in clinical practice as a source of pain in a variety of patients (athletes, older patients, and patients with predisposing conditions). Radiography is the imaging modality of choice for baseline diagnosis. MRI has greatly improved our ability to diagnose radiographically occult stress fractures. Nuclear medicine scintigraphy and CT may also be useful as diagnostic tools. Although fatigue and insufficiency fractures can be self-limited and go on to healing even without diagnosis, there is usually value in initiating prompt therapeutic measures as incomplete stress fractures have the potential to progress to completion, necessitating surgery. This is particularly important in the setting of stress fractures of the femoral neck. Accuracy in the identification of these injuries is also relevant because the differential diagnosis includes entities that would otherwise be treated differently (ie, metastatic disease). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Therapeutic ultrasound related pain threshold in elite track & field athletes with tibial bone stress injuries

OBJECTIVE

Tibial stress injuries are challenging in terms of early diagnosis, management strategy, and safe return-to-play. In the present study, pain production associated with the application of therapeutic ultrasound (TUS) was used as a primary diagnostic tool to assess tibial bone stress injuries, and the sensitivity of this procedure was compared with Magnetic Resonance Imaging (MRI).

SUBJECT AND METHODS

The study was designed as a retrospective analysis of prospectively collected data on tibial bone stress injuries in elite Track and field athletes attending the National Track and Field Athletics Centre in Thessaloniki, Greece, in the period 1995-2007. All patients underwent evaluation by TUS, and the sensitivity of the procedure was compared with MRI.

RESULTS

Four of 29 athletes showed a positive TUS examination for stress injury while MRI showed normal findings. Additionally, 5 athletes evidenced MRI findings typical of a tibial bone stress injury, while TUS evaluation was negative. Using MRI as the standard, TUS displayed a sensitivity of 79.2%.

CONCLUSION

Therapeutic ultrasound is a reproducible modality with satisfactory reliability and sensitivity related to MRI, and could represent a useful tool for clinicians to primarily assess suspected tibial bone stress injuries in high qualification Track and Field athletes.

Emerging role of bone scintigraphy single-photon emission computed tomography/computed tomography in foot pain management

Foot and ankle joints being weight-bearing joints are commonly subjected to wear and tear and are prone to traumatic and other pathologies. Most of these foot and ankle pathologies present with pain. The diagnosis of pathology and localization of pain generators is difficult owing to the complex anatomy of the foot and similar clinical presentation. This makes the management of foot pain clinically challenging. Conventional anatomical imaging modalities are commonly employed for evaluation of any anatomical defect; however, these modalities often fail to describe the functional significance of the anatomical lesions, especially in presence of multiple lesions which is common in ankle and foot; however, hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) by virtue of its dual modalities, that is, highly sensitive functional imaging and highly specific anatomical imaging can serve as a problem-solving tool in patient management. This review attempts to describe the role of hybrid SPECT/CT in overcoming the limitation of conventional imaging and describes its potential application in the management of foot and ankle pain.

Tibial Stress Fracture and "Shin Splint" Syndrome in the Same Patient Diagnosed on 99mTC-Methylene Diphosphonate Bone Scintigraphy and Single-Photon Emission/Computed Tomography

We present a case of an 18-year-old male athlete who presented with complaints of right lower leg pain for 10 days following intense exercise. The most likely diagnosis was a possible tibial stress fracture or a ''shin splint'' syndrome. The radiograph did not reveal any significant abnormality in the form of any fracture or a cortical break. We performed planar bone scintigraphy including single-photon emission computed tomography (CT)/CT that revealed the presence of the two concomitant pathologies in the form of a hot spot which corresponded with a bone lesion in the tibial stress fracture and subtle remodeling activity without evidence of significant cortical lesion in the shin splints in bilateral lower limbs (R>L).

Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

Bone Stress Injuries in Runners: a Review for Raising Interest in Stress Fractures in Korea

A bone stress injury (BSI) means that the bones cannot tolerate repeated mechanical loads, resulting in structural fatigue and local bone pain. A delay in BSI diagnosis can lead to more serious injuries, such as stress fractures that require longer treatment periods. Therefore, early detection of BSI is an essential part of management. Risk factors for BSI development include biological and biomechanical factors. Medical history and physical examination are the basics for a BSI diagnosis, and magnetic resonance imaging is helpful for confirming and grading. In this paper, the authors review the overall content of BSI and stress fractures which are common in runners. Through this review, we hope that interest in stress fractures will be raised in Korea and that active researches will be conducted.

ACR Appropriateness Criteria® Stress (Fatigue/Insufficiency) Fracture, Including Sacrum, Excluding Other Vertebrae

Stress fractures, including both fatigue and insufficiency types, are frequently encountered in clinical practice as a source of pain in both athletes and patients with predisposing conditions. Radiography is the imaging modality of choice for baseline diagnosis. MRI has greatly improved our ability to diagnose radiographically occult stress fractures. Tc-99m bone scan and CT may also be useful as diagnostic tools. Although fatigue and insufficiency fractures can be self-limited and go onto healing even without diagnosis, there is usually value in initiating prompt therapeutic measures as incomplete stress fractures have the potential of progressing to completion and requiring more invasive treatment or delay in return to activity. This is particularly important in the setting of stress fractures of the femoral neck. Accuracy in the identification of these injuries is also relevant because the differential diagnosis includes entities that would otherwise be treated significantly different (ie, osteoid osteoma, osteomyelitis, and metastasis). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Stress Fractures of the Calcaneus Diagnosed by Sonography: Report of 8 Cases

We present a retrospective review of 8 patients (6 women and 2 men, with an age range of 46-80 years; mean age, 60.2 years) in whom sonography was used to diagnose a calcaneal stress fracture. Sonography was performed because of a clinical suspicion of soft tissue injuries. Two patients were first assessed by standard radiography; for the remaining patients, sonography was the first imaging technique used. Patients were subsequently examined by magnetic resonance imaging, except for 1 patient in whom the diagnosis was made only on a clinical-sonographic correlation. On sonography, there was thickening of the periosteum and subcutaneous edema in all patients; a calcified bone callus was evident in none of the 8 patients. Cortical irregularities were found in 6 of 8 patients. Color Doppler imaging showed local hypervascular changes of the periosteum in all patients. Sonography, together with clinical findings, can be used to diagnose a calcaneal stress fracture. We suggest that sonologists should include a calcaneal stress fracture in their differential diagnosis in cases of mechanical hind foot pain. They must also include, as a part of every sonographic examination of the ankle, an examination of the calcaneus and be aware of the sonographic appearance of stress fractures. If the diagnosis is still uncertain after the sonographic examination, magnetic resonance imaging should be prescribed.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture.

Diagnostic Accuracy of Various Imaging Modalities for Suspected Lower Extremity Stress Fractures: A Systematic Review With Evidence-Based Recommendations for Clinical Practice

BACKGROUND

The literature is filled with conflicting findings regarding diagnostic accuracy and protocols for imaging suspected lower extremity stress fractures. The absence of systematic reviews on this topic has limited the development of evidence-based recommendations for appropriate imaging protocols in cases of suspected lower extremity stress fractures.

PURPOSE

To determine the diagnostic accuracy statistics of imaging modalities used to diagnose lower extremity stress fractures and to synthesize evidence-based recommendations for clinical practice.

STUDY DESIGN

Systematic review.

METHODS

A generic search strategy for published studies was performed using multiple databases. A study was eligible for inclusion if it met all of the following criteria: (1) at least 1 diagnostic imaging modality was studied, (2) at least 1 radiological reference standard was used, (3) the study reported or allowed computation of diagnostic accuracy statistics (sensitivity, specificity, positive likelihood ratio, negative likelihood ratio), (4) a full-text version was available, (5) the article was written in English, and (6) the study included lower extremity stress fractures. Studies that examined asymptomatic individuals or patients with fractures due to disease or pharmacologic intervention were excluded.

RESULTS

Reported sensitivity and specificity (95% CI) were as follows: For conventional radiography, sensitivity ranged from 12% (0%-29%) to 56% (39%-72%) and specificity ranged from 88% (55%-100%) to 96% (87%-100%). For nuclear scintigraphy (NS), sensitivity ranged from 50% (23%-77%) to 97% (90%-100%) and specificity from 33% (12%-53%) to 98% (93%-100%). For magnetic resonance imaging (MRI), sensitivity ranged from 68% (45%-90%) to 99% (95%-100%) and specificity from 4% (0%-11%) to 97% (88%-100%). For computed tomography, sensitivity ranged from 32% (8%-57%) to 38% (16%-59%) and specificity from 88% (55%-100%) to 98% (91%-100%). For ultrasound, sensitivity ranged from 43% (26%-61%) to 99% (95%-100%) and specificity from 13% (0%-45%) to 79% (61%-96%).

CONCLUSION

MRI was identified as the most sensitive and specific imaging test for diagnosing stress fractures of the lower extremity. When MRI is available, NS is not recommended because of its low specificity, high dosage of ionizing radiation, and other limitations. Conventional radiographs are likely to result in false negatives upon initial presentation, particularly in the early stages of stress fracture, and in some cases may not reveal an existing stress fracture at any time. A diagnostic imaging algorithm was developed with specific recommendations for cost-efficient imaging of low-risk and high-risk suspected stress fractures.

Overuse lower extremity injuries in sports

When athletes train harder the risk of injury increases, and there are several common overuse injuries to the lower extremity. Three of the most common lower extremity overuse injuries in sports are discussed including the diagnosis and treatments: medial tibal stress syndrome, iliotibial band syndrome, and stress fractures. The charge of sports medicine professionals is to identify and treat the cause of the injuries and not just treat the symptoms. Symptomatology is an excellent guide to healing and often the patient leads the physician to the proper diagnosis through an investigation of the athlete's training program, past injury history, dietary habits, choice of footwear, and training surface.

Management and prevention of bone stress injuries in long-distance runners

SYNOPSIS

Bone stress injury (BSI) represents the inability of bone to withstand repetitive loading, which results in structural fatigue and localized bone pain and tenderness. A BSI occurs along a pathology continuum that begins with a stress reaction, which can progress to a stress fracture and, ultimately, a complete bone fracture. Bone stress injuries are a source of concern in long-distance runners, not only because of their frequency and the morbidity they cause but also because of their tendency to recur. While most BSIs readily heal following a period of modified loading and a progressive return to running activities, the high recurrence rate of BSIs signals a need to address their underlying causative factors. A BSI results from disruption of the homeostasis between microdamage formation and its removal. Microdamage accumulation and subsequent risk for development of a BSI are related both to the load applied to a bone and to the ability of the bone to resist load. The former is more amenable to intervention and may be modified by interventions aimed at training-program design, reducing impact-related forces (eg, instructing an athlete to run "softer" or with a higher stride rate), and increasing the strength and/or endurance of local musculature (eg, strengthening the calf for tibial BSIs and the foot intrinsics for BSIs of the metatarsals). Similarly, malalignments and abnormal movement patterns should be explored and addressed. The current commentary discusses management and prevention of BSIs in runners. In doing so, information is provided on the pathophysiology, epidemiology, risk factors, clinical diagnosis, and classification of BSIs.

LEVEL OF EVIDENCE

Therapy, level 5.

Epiphyseal stress fractures of finger phalanges in adolescent climbing athletes: a 3.0-Tesla magnetic resonance imaging evaluation

OBJECTIVES

To study the value of 3.0-Tesla magnetic resonance imaging for baseline and follow-up assessment of epiphyseal finger phalanx stress fractures in a collective of 7 consecutive adolescent climbing athletes.

MATERIALS AND METHODS

Baseline MRI was performed in 8 fingers of 7 adolescent athletes (mean age 13.8 years, female:male = 2:5) with clinically suspected stress fracture of the fingers acquired during climbing sports. Follow-up MRI was performed after functional therapy with training interruption for 6 weeks (n = 6) and 12 weeks (n = 1). Images were analysed retrospectively and independently by two readers using an MRI grading score from 0 (no pathology) to 4 (bone marrow oedema and clear depiction of a sharp fracture line with surrounding inflammatory soft tissue reaction).

RESULTS

A total of 8 baseline and 7 follow-up MRIs were analysed. In 7 out of 8 fingers a stress fracture line Salter-Harris III and in all fingers a bone marrow oedema were diagnosed at the epiphyseal base of the middle phalanx. The average grading score was 3.37 in the initial MRI and 1.43 in the follow-up MRI indicating fracture healing in all fingers. Kappa value for interobserver variability was 0.86, representing almost perfect interobserver agreement.

CONCLUSIONS

3-T MRI is a promising diagnostic technique for baseline assessment of epiphyseal finger phalanx stress fractures and for follow-up evaluation of fracture healing.

Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting

Background

Yttrium-90 (⁹⁰Y) positron emission tomography with integrated computed tomography (PET/CT) represents a technological leap from ⁹⁰Y bremsstrahlung single-photon emission computed tomography with integrated computed tomography (SPECT/CT) by coincidence imaging of low abundance internal pair production. Encouraged by favorable early experiences, we implemented post-radioembolization ⁹⁰Y PET/CT as an adjunct to ⁹⁰Y bremsstrahlung SPECT/CT in diagnostic reporting.

Methods

This is a retrospective review of all paired ⁹⁰Y PET/CT and ⁹⁰Y bremsstrahlung SPECT/CT scans over a 1-year period. We compared image resolution, ability to confirm technical success, detection of non-target activity, and providing conclusive information about ⁹⁰Y activity within targeted tumor vascular thrombosis. ⁹⁰Y resin microspheres were used. ⁹⁰Y PET/CT was performed on a conventional time-of-flight lutetium-yttrium-oxyorthosilicate scanner with minor modifications to acquisition and reconstruction parameters. Specific findings on ⁹⁰Y PET/CT were corroborated by ⁹⁰Y bremsstrahlung SPECT/CT, ^99mTc macroaggregated albumin SPECT/CT, follow-up diagnostic imaging or review of clinical records.

Results

Diagnostic reporting recommendations were developed from our collective experience across 44 paired scans. Emphasis on the continuity of care improved overall diagnostic accuracy and reporting confidence of the operator. With proper technique, the presence of background noise did not pose a problem for diagnostic reporting. A counter-intuitive but effective technique of detecting non-target activity is proposed, based on the pattern of activity and its relation to underlying anatomy, instead of its visual intensity. In a sub-analysis of 23 patients with a median follow-up of 5.4 months, ⁹⁰Y PET/CT consistently outperformed ⁹⁰Y bremsstrahlung SPECT/CT in all aspects of qualitative analysis, including assessment for non-target activity and tumor vascular thrombosis. Parts of viscera closely adjacent to the liver remain challenging for non-target activity detection, compounded by a tendency for mis-registration.

Conclusions

Adherence to proper diagnostic reporting technique and emphasis on continuity of care are vital to the clinical utility of post-radioembolization ⁹⁰Y PET/CT. ⁹⁰Y PET/CT is superior to ⁹⁰Y bremsstrahlung SPECT/CT for the assessment of target and non-target activity.

Estimation of return-to-sports-time for athletes with stress fracture - an approach combining risk level of fracture site with severity based on imaging

Background

The aim was to compare the return-to-sports-time (RTST) following stress fractures on the basis of site and severity of injury. This retrospective study was set up at a single institution. Diagnosis was confirmed by an interdisciplinary adjudication panel and images were rated in a blinded-read setting.

Methods

52 athletes (female, n = 30; male, n = 22; mean age, 22.8 years) with stress fracture (SFX) who had undergone at least one examination, either MRI or bone scintigraphy, were included. Magnetic resonance images (MRI) and/or bone scintigraphy (BS) of SFX were classified as either low- or high-grade SFX, according to existing grading systems. For MRI, high-grade SFX was defined as visibility of a fracture line or bone marrow edema in T1-, T2-weighted and short tau inversion recovery (STIR) sequences, with low-grade SFX showing no fracture line and bone marrow edema only in STIR and/or T2-weighted sequences. In BS images, a mild and poorly defined focal tracer uptake represented a low-grade lesion, whereas an intense and sharply marginated uptake marked a high-grade SFX. In addition, all injuries were categorized by location as high- or low-risk stress fractures. RTST was obtained from the clinical records. All patients were treated according to a non-weight-bearing treatment plan and comprehensive follow-up data was complete until full recovery. Two-sided Wilcoxon’s rank sum test was used for group comparisons.

Results

High-risk SFX had a mean RTST of 132 days (d) [IQR 64d – 132d] compared to 119d [IQR 50d – 110d] for low-risk sites (p = 0.19). RTST was significantly longer (p = 0.01) in high-grade lesions [mean, 143d; IQR 66d – 134d] than in low-grade [mean, 95d; IQR 42d – 94d]. Analysis of high-risk SFX showed no difference in RTST (p = 0.45) between high- and low-grade [mean, 131d; IQR 72d – 123d vs. mean, 135d; IQR 63d – 132d]. In contrast, the difference was significant for low-risk SFX (p = 0.005) [low-grade; mean, 61d; IQR 35d – 78d vs. high-grade; mean, 153d; IQR 64d – 164d].

Conclusion

For SFX at low-risk sites, the significant difference in RTST between low- and high-grade lesions allows more accurate estimation of RTST by this approach. Both location of the injury and severity determined by imaging should therefore be considered for prediction of RTST.

MRI versus bone scintigraphy. Evaluation for diagnosis and grading of stress injuries

AIM

This study was set up to determine the value of magnetic resonance imaging (MRI) and bone scintigraphy (BS) for the diagnosis of stress injuries in athletes, and furthermore to assess reliability and prediction of healing time.

PATIENTS, METHODS

Imaging data was analyzed retrospectively from 28 athletes who had received MRI and BS examinations for suspected stress injuries. MRI- and BS-data were rated by three specialists each in a blinded read, using a 5-point score (i.e. 0-4: inconspicuous to high-grade stress fracture). An interdisciplinary expert truth-panel set the reference standard. Standard statistical parameters, Fleiss' kappa (κ), and group comparisons were calculated.

RESULTS

The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) for detection of stress injuries were 71.4%, 85.7%, 78.6%, 83.3% and, 75.0%, for MRI and 92.9%, 73.8%, 83.3%, 78.0% and, 91.2% for BS, respectively. Interobserver reliability for the diagnosis of a stress injury was κ = 0.9 for BS and κ = 0.85 for MRI. Mean healing times of mild (grades 1 and 2) and severe (grades 3 and 4) stress injuries were 88 days (d) versus 142d for BS and 57d versus 116d for MRI. No significant difference in healing time could be shown.

CONCLUSIONS

MRI and BS reliably detect stress injuries. MRI is to be recommended as the primary imaging modality due to its potential for assessment of differential diagnoses and the lack of radiation exposure, the value of BS lies in the exclusion of stress fractures after inconclusive MRI examinations.

Ultrasound as a primary evaluation tool of bone stress injuries in elite track and field athletes

BACKGROUND

Little is known about therapeutic ultrasound (TUS) to diagnose bone stress injuries.

HYPOTHESIS

Therapeutic ultrasound is an accurate, cost-efficient alternative to other imaging methods for primary assessment of bone stress injuries.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

One hundred thirteen elite track and field athletes (mean age, 20.1 years; range, 17-28 years) underwent TUS and magnetic resonance imaging (MRI) for clinical suspicion of a bone stress injury. A 5-stage MRI grading system was used to classify bone stress injuries. Sensitivity, specificity, accuracy, and positive and negative predictive values of TUS were calculated using MRI as the standard for diagnosis.

RESULTS

At MRI, of 113 assessed patients, 3 (2.7%) had grade 0 injuries, 12 (10.6%) had grade 1, 15 (13.3%) had grade 2, 77 (68.2%) had grade 3, and 6 (5.3%) had grade 4. At TUS, no injury was detected in 22 of 113 patients: 2 with grade 0 injury, 8 with grade 1, 8 with grade 2, and 4 with grade 3. Using MRI as the gold standard, TUS showed 81.8% sensitivity, 66.6% specificity, 99.0% positive predictive value, 13.4% negative predictive value, and 81.4% accuracy.

CONCLUSION

Therapeutic ultrasound is a reproducible procedure that is reliable to diagnose bone stress injuries.