Sanjay Vijayanathan

SPECT/CT in Imaging Foot and Ankle Pathology—The Demise of Other Coregistration Techniques

Disorders of the ankle and foot are common and given the complex anatomy and function of the foot, they present a significant clinical challenge. Imaging plays a crucial role in the management of these patients, with multiple imaging options available to the clinician. The American College of radiology has set the appropriateness criteria for the use of the available investigating modalities in the management of foot and ankle pathologies. These are broadly classified into anatomical and functional imaging modalities. Recently, single-photon emission computed tomography and/or computed tomography scanners, which can elegantly combine functional and anatomical images have been introduced, promising an exciting and important development. This review describes our clinical experience with single-photon emission computed tomography and/or computed tomography and discusses potential applications of these techniques.

Additional benefit of SPECT-CT in investigating heel pain.

Abstract:A 21-year-old man presented with a 3-year history of right heel pain. There was no history of trauma. Clinically, Achilles tendonitis was suspected.Plain radiography demonstrated a right plantar calcaneal spur. Bone scintigraphy (planar imaging and SPECT/CT) revealed changes in keeping with

Advantages and Limitations of Imaging the Musculoskeletal System by Conventional Radiological, Radionuclide, and Hybrid Modalities

The endpoint of an efficient and accurate diagnosis of musculoskeletal pathology can take many different routes. Currently, conventional radiological techniques, such as plain radiography, ultrasonography, computed tomography, and magnetic resonance imaging are used in the assessment of patients with benign and malignant bone disease. An understanding of the advantages and limitations of the modalities available will help expedite diagnosis, and hence treatment. In this review, we discuss the advantages and limitations of the modalities available in investigating benign and malignant musculoskeletal pathology.

The role of 99mTc-diphosphonate bone SPECT/CT in the ankle and foot.

The evaluation of the osseous ankle and foot pathology often poses a clinical and diagnostic challenge because of the complex anatomy and structural biomechanics of the region. Further investigation involves a multimodality imaging approach. Although both structural and functional imaging techniques have their strengths, namely, the high specificity of the former and superior sensitivity of the latter, they also have a number of limitations when used in isolation. These include the inability to determine the functional significance of pathological anatomical abnormalities or to further characterize or localize abnormal metabolic activity. The development of integrated single-photon emission computed tomography/computed tomography systems has aimed to overcome the limitations of separate anatomical and functional imaging techniques. This may be of particular value in ankle and foot assessments, in which multiple joints may be affected by different pathologies. This review article aims to highlight the role of both structural and functional imaging techniques, with particular emphasis on the incremental value of single-photon emission computed tomography/computed tomography in evaluation of this complex anatomical region.

Potential role of multislice SPECT/CT in impingement syndrome and soft-tissue pathology of the ankle and foot.

IntroductionImpingement syndrome and soft-tissue pathology have been recognized as significant causes of chronic ankle pain. Conventional bone scintigraphy was traditionally used for osseous pathology, but with the advent of single photon emission computed tomography/computed tomography (SPECT/CT) the role of bone scintigraphy in these patients is being reconsidered. AimThe aim of this study was to assess the potential role of multislice SPECT/CT in diagnosing impingement syndrome and soft-tissue pathology of the ankle and foot. Materials and methodsA total of 209 patients (age range: 19–80 years) underwent a two-phase Tc-99m methylene diphosphonate bone scan followed by SPECT/CT between 2006 and 2009 for various ankle and foot pathologies. These scans were reviewed for impingement syndrome and soft-tissue pathology. The diagnosis made on SPECT/CT was compared with the clinical diagnosis, and two-phase bone scan findings and additional findings obtained from SPECT/CT were noted. ResultsOut of the 209 patients, 43 (21%) were diagnosed with impingement syndrome or soft-tissue pathology. Clinical diagnosis versus bone SPECT/CT: in 24/43 (56%) patients, SPECT/CT provided information not suspected on clinical diagnosis. In 19/43 (44%) patients, SPECT/CT confirmed the clinical diagnosis. Two-phase bone scan versus SPECT/CT: in 31/43 (72%) patients, SPECT/CT provided additional information, which was not diagnosed on the conventional two-phase bone scan. The findings of the two-phase bone scan and SPECT/CT were concordant in 12/43 (28%) patients. ConclusionTc-99m methylene diphosphonate bone SPECT/CT is useful in localizing and characterizing impingement syndrome and soft-tissue pathology in patients with ankle/foot pain. SPECT/CT may complement MRI and ultrasonography in the investigation of impingement syndrome and soft-tissue pathology.

Tuberculosis of the spine on Tc-99m MDP bone scan: additional role of SPECT-CT.

Dedicated multislice single-photon emission computed tomography-computed tomography (SPECT-CT) is useful for accurate anatomic localization and lesion characterization of abnormal findings on planar scintigraphy. We present a case of a 33-year-old woman with a history of low back pain. Lumbar spine radiographs demonstrated irregularity of the superior end plate of L2 with an associated compression fracture. A Tc-99m MDP bone scan was performed given her young age and the absence of a history of trauma. The whole body planar imaging revealed nonspecific findings of diffuse linear increased tracer uptake involving L2. The SPECT-CT findings were in keeping with spinal tuberculosis. This was confirmed with culture of CT-guided aspiration of a left psoas collection, which revealed heavy growth of Mycobacterium tuberculosis. This case highlights the benefits of multislice SPECT-CT imaging in the anatomic localization of increased metabolic activity and provision of additional diagnostic information. This enabled rapid diagnosis and management.

Beware of the focal uptake at the ischium on the bone scan in prostate cancer.

RationaleThe isotope bone scan is routinely used in the management of prostate cancer as the skeleton is the second most common area of metastasis after lymph nodes. A classic site of involvement in the pelvis is the ischium, and the aim of this study was to assess the value of single-photon emission computed tomography/computed tomography (SPECT/CT) imaging in patients with focal ischial uptake on the planar scan. Materials and methodsThis was a retrospective study of consecutive 150 patients with prostate cancer who were referred for a whole-body bone scan between August 2007 and 2008. Two experienced nuclear medicine consultants along with a musculoskeletal radiologist reviewed the scans. ResultsSixty-eight patients were diagnosed with widespread metastases and 46 patients showed typical degenerative disease changes on planar whole-body imaging. SPECT/CT imaging was done in 36 patients to clarify the diagnosis in areas of indeterminate uptake noted on planar whole-body imaging. Ten of these 36 patients who had focal increased ischial uptake were included in the study. Only three of these 10 patients were diagnosed as having a metastatic lesion with the presence of an enthesopathy, a common finding. ConclusionIsolated focal uptake in the ischium is a relatively common finding in patients with prostate cancer and there is concern that this, on occasion, could be misinterpreted as metastasis. SPECT/CT imaging has an important role in differentiating a benign from a malignant lesion.

Diagnosis of infection in the diabetic foot using 18 F‐FDG PET/CT: a sweet alternative?

Accurate diagnosis and management of skeletal infectionis crucial and challenging. The goals of imaging ininfection are (a) to establish an early and reliable diag-nosis, as clinical and laboratory markers are often non-specific in the early stages, (b) to localize, characterizeand define the extent of involvement (often influences ordirects diagnostic and/or therapeutic intervention), and (c)to assess treatment response [1]. Such considerations areparticularly important in several select groups of patientssuch as diabetics, who are relatively more prone tocutaneous ulceration and its related complications. Ap-proximately 2 million cases of musculoskeletal infectionare diagnosed each year in the USA [2] and MRI is themost commonly used imaging modality. MRI with gado-linium contrast enhancement is useful (a) in differentiat-ing abscess from inflammatory tissue, (b) to differentiateviable from nonviable tissue, and (c) to evaluate boneinvolvement [1]. However, the presence of preexistingrenal impairment is a potentially major limitation in theuse of MRI with gadolinium contrast enhancement. Metalartefacts may obscure underlying pathology, if there hasbeen previous intervention [1] and it may be difficult todistinguish osteomyelitis from Charcot’s neuroarthropathyin the diabetic foot using MRI alone.Radionuclide imaging plays an important role in theevaluation of infection and most would agree that radio-labelled leukocyte imaging remains a key investigation inthe assessment of infection and in particular fever of un-known origin (FUO), vascular graft infections, orthopaedicinfections and infections complicating the diabetic foot [3,4]. Despite advances in imaging techniques, and newertracers, it has not been possible to achieve 100 % accuracyin diagnosis, but the goal remains.In the current issue of the European Journal of NuclearMedicine and Molecular Imaging, Kagna et al. present theirresults assessing the role of

Recognition of the femoroacetabular impingement syndrome on MDP SPECT CT

The femoroacetabular impingement syndrome (FAI) is becoming increasingly recognized as a cause of intermittent hip or groin pain in physically active young adults (ie, 4th to 5th decades), which leads to early osteoarthritis. Repeated microtrauma from impingement of the femoral neck against the acetabulum occurs in those with predisposing hip geometries. Early diagnosis of this condition allows appropriate management, aimed at reducing the need for total hip replacement. This case demonstrates that FAI may be appreciated on SPECT CT MDP bone scanning.

Tc-99m MDP bone scintigraphy in septic shock

An 8-year-old girl presented with a history of diarrhea, vomiting, and drowsiness. Clinical examination confirmed septic shock with marked metabolic acidosis. As a complication of septicemia, severe ischemia of all 4 limbs was noted from day 1 and she subsequently developed peripheral gangrene. Tc-99m MDP bone scan showed extensive bone infarction in all 4 limbs. Early diagnosis of osteonecrosis and amputation may prevent worsening of sepsis. However, it is not possible to clinically demarcate the level of amputation. Bone scan is a useful diagnostic tool in determining the appropriate level of amputation.