Contributions of nuclear medicine in paediatric non-tumour musculoskeletal pathology

Non-tumour musculoskeletal pathology in children represents a high percentage of the nuclear medicine studies requested by paediatricians. As these are immature bones and joints, in constant growth and remodelling, they present their own physiological and anatomical peculiarities that require a specific management for the paediatric age group. Using different clinical scenarios frequently observed in medical appointments (limping, back pain or fever, among others), we have summarised the possible findings or artefacts that can be obtained in the different Nuclear Medicine explorations, including bone scintigraphy and hybrid images such as PET/CT. To obtain high quality images requires careful attention to technique and positioning in children. Bone scintigraphy is a common paediatric nuclear medicine procedure and plays an important role in the diagnosis of musculoskeletal pathologies and can be complemented by techniques such as SPECT to improve localisation and diagnostic accuracy. In addition, ¹⁸F-FDG PET/CT is increasingly applied in the evaluation of children. This article reviews the usual indications of, mainly, bone scintigraphy and ¹⁸F-FDG PET/CT in paediatric non-tumour musculoskeletal diseases, how to interpret them properly, being essential to know the normal physiological distribution of each radiopharmaceutical, as well as the common variants of paediatric growth that can simulate disease, implying possible misinterpretations between normal and pathological structures.

Nuclear Medicine in the diagnosis of pathologies of the spine: role of hybrid imaging

Clinical problems in the human spine are still common in our society, often causing pain and can also limit movement. Back pain is a very common clinical entity, although difficult to diagnose due to its multifactorial nature. There are multiple processes that can alter the structure of the spine, injure vertebrae and/or the surrounding tissue. For the study of the spine, image diagnosis is essential, and within this, molecular hybrid techniques play an important role by providing us with an image of functional and morphological fusion. Among these, SPECT/CT is key in the diagnosis of traumatic and stress pathology, allowing us to locate hidden vertebral fractures, and is also very useful in degenerative and post-surgical pathology. On the other hand, PET/CT with 18F-FDG also plays an important role in the management and monitoring of infectious and oncological processes. This review describes the application of these hybrid techniques in the different pathologies of the spine and the findings of their images, being very useful for the diagnostic assessment and therapeutic management of the patient.

Clinical applications of nuclear medicine in the diagnosis and assessment of musculoskeletal sports injuries

Increased participation in sports and physical exercise are widely promoted as an approach to a physically active lifestyle which has a positive effect on healthy aging, in patients and athletes of all ages, beginners and experts, including amateur athletes and professional athletes. Unfortunately, this has caused a higher incidence of sports-related injuries. In the sports context, the early and accurate diagnosis of injuries is of the utmost importance in order to enable early treatment to achieve a full recovery. Imaging techniques are increasingly important for the successful diagnosis and management of the patient. The nuclear medicine techniques with bone tracers provide physiological and metabolic information in the early phases of musculoskeletal injuries, which often precede anatomical changes and they reflect changes in bone turnover. This allows early diagnosis, along with evaluation of the activity and phase of the injury. In this article, the applications of nuclear medicine techniques, focusing on bone scintigraphy, alongside the important contribution of hybrid studies (SPECT/CT), in the diagnosis of bone and soft tissue sports injuries, will be described. In addition, we explain their usefulness in the expression of the pathophysiology of these lesions and their scintigraphic patterns. The article will also describe biomechanical and physiopathological aspects, injury mechanisms and clinical presentations of bone and joint sports injuries, knowledge of this is essential for the correct diagnostic assessment of imaging studies.

Role of Nuclear Medicine in the diagnosis of musculoskeletal infection: a review

Inflammatory and infectious osteoarticular diseases can cause serious consequences for the patient if they are not diagnosed on time. In the last decades, different modalities of nuclear medicine have allowed to study the physiopathology of these processes, and nowadays, they play an important role in diagnosis, characterization and monitoring of musculoskeletal infectious diseases. Therefore, it is essential that every nuclear medicine physician have a vision of the advantages and disadvantages of each method and know how to use them correctly in the diagnosis of the patient. This article highlights the role of nuclear medicine in standardizing the diagnostic approach in patients with infectious/inflammatory diseases, in particular in peripheral osteomyelitis, septic arthritis, prosthetic joint infections, infected diabetic foot and spinal infections. The authors reveal the role of the most common radionuclides tests, with their advantages and clinical indications, to achieve an adequate diagnosis of infection and inflammation.

Complications of shoulder arthroplasty: added value of SPECT/CT imaging

The incidence of prosthetic shoulder replacements has increased considerably in recent years, as well as the complications derived from the procedure. The correct diagnosis of each type of complication is essential for therapeutic decision making, which is currently based on the information provided by radiological and nuclear medicine imaging. Nevertheless, both techniques have intrinsic limitations that could be mostly overcome with the advent of the hybrid SPECT/CT imaging, which is set to play a fundamental role in the evaluation of shoulder prostheses.

Comparison of 99mTc-MDP SPECT qualitative vs quantitative results in patients with suspected condylar hyperplasia

OBJECTIVE

To compare qualitative vs quantitative results of Single Photon Emission Computerised Tomography (SPECT), calculated from percentage of ^99mTc-MDP (methylene diphosphonate) uptake, in condyles of patients with a presumptive clinical diagnosis of condylar hyperplasia.

MATERIALS AND METHOD

A retrospective, descriptive study was conducted on the ^99mTc-MDP SPECT bone scintigraphy reports from 51 patients, with clinical impression of facial asymmetry related to condylar hyperplasia referred by their specialist in orthodontics or maxillofacial surgery, to a nuclear medicine department in order to take this type of test. Quantitative data from ^99mTc-MDP condylar uptake of each were obtained and compared with qualitative image interpretation reported by a nuclear medicine expert.

RESULTS

The concordances between the 51 qualitative and quantitative reports results was established. The total sample included 32 women (63%) and 19 men (37%). The patient age range was 13-45 years (21±8 years). According to qualitative reports, 19 patients were positive for right side condylar hyperplasia, 12 for left side condylar hyperplasia, with 8 bilateral, and 12 negative. The quantitative reports diagnosed 16 positives for right side condylar hyperplasia, 10 for left side condylar hyperplasia, and 25 negatives.

CONCLUSIONS

Nuclear medicine images are an important diagnostic tool, but the qualitative interpretation of the images is not as reliable as the quantitative calculation. The agreement between the two types of report is low (39.2%, Kappa=0.13; P>.2). The main limitation of quantitative reports is that they do not register bilateral condylar hyperplasia cases.

Symptomatic hypophosphataemic osteomalacia secondary to the treatment with iron carboxymaltose detected in bone scintigraphy

The development of hypophosphataemic osteomalacia has been linked with several treatments, mainly antiretroviral and intravenous iron administration. The frequency of the hypophosphataemia requires monitoring the phosphate after the administration of iron carboxymaltose. We describe a case of a woman with no calcium-phosphorous metabolism disorder, to whom this treatment was prescribed for anaemia due to menorrhagia and intolerance to oral iron. She started with oligoarticular pain, which was spreading with a significant functional loss. The relationship with the administration of intravenous iron was discovered when scintigraphic findings together with laboratory results led to a diagnosis of hypophosphataemic osteomalacia. The patient responded satisfactorily to treatment with phosphate both clinically and in the follow-up bone scintigraphy.

An unusual presentation of primary hyperparathyroidism: multiple brown tumors and coexisting thyroid carcinoma

We present a patient with a complex clinical picture of primary hyperparathyroidism with multiple destructive skeletal lesions suspicious of bone metastases and concomitant multifocal papillary thyroid carcinoma with a metastatic central lymph node. He presented with progressively worsening right hip pain and restricted motion. Magnetic resonance imaging revealed multiple lytic lesions involving predominantly the right trochanter minor and the left inferior and posterior pubic rami. Biochemical tests were consistent with primary hyperparathyroidism. Neck ultrasound and parathyroid scintigraphy revealed a single parathyroid adenoma and a thyroid nodule, preoperative cytology of which confirmed papillary thyroid carcinoma, as did the final surgical specimen. Biochemical results, regarding hyperparathyroidism, declined to normal levels and his complaints gradually decreased after surgery. Postoperative whole body bone scintigraphy showed increased tracer uptakes at multiple sites, but they were proved to be metabolically inactive by fluorodeoxyglucose positron emission tomography/computed tomography.

Bone scintigraphy as cornerstone in the diagnosis of Erdheim-Chester disease

The Erdheim-Chester disease (ECD) is an extremely rare form of non-Langerhans cell histiocytosis. The main difficulty for its diagnosis lies in the wide variety of non-specific symptoms and signs that can occur in the disease process, leading, therefore, to there being no clear-cut algorithm as a guide for an optimal biopsy to confirm the diagnosis. An 81-year-old male with history of diabetes insipidus was admitted due to non-specific respiratory signs. Imaging techniques revealed osteoblastic lesions in the lumbar spine. Whole-body bone-scintigraphy (BS) was performed, in which lesions involving the axial and appendicular skeleton, with different rates of osteoblastic activity, were observed. This highlighted a symmetrical severely intense uptake in the knees, leading to an accurate biopsy specimen that enabled making the definitive diagnosis. BS is a widely available, safe, and inexpensive technique that shows a characteristic pattern of uptake for ECD, thus its use is highly recommended for screening and guiding biopsy if clinical suspicion exists. Furthermore, when the scintigraphy pattern is incidentally observed, biopsy of increased uptake areas (tibia preferably) is mandatory in order to rule out the disease.

(18)F-FDG PET/CT versus bone scintigraphy in the follow-up of gastric cancer

A 53-year-old patient underwent a positron emission tomography/computed tomography with 2-fluoro-2-deoxy-d-glucose ((18)F-FDG PET/CT) in the suspicious of gastric tumor recurrence (mediastinal and abdominal lymph nodes). PET/CT identified only an area of (18)F-FDGuptake in the twelfth thoracic vertebrae. Unexpectedly, a bone scintigraphy revealed many "hot" spots changing the diagnosis (single metastasis versus plurimetastatic disease) and impacting on patient's management.

Numb chin syndrome as a manifestation of jaw metastasis diagnosed in a bone scan

In many cases, numb chin syndrome (NCS) may represent a banal pathology. However, as it can be associated with malignant processes, its presence should alert the clinician of a possible occult disease. In patients already diagnosed with cancer, it often represents an ominous sign that indicates poor prognosis, due to the rapid progress of the disease. The case is presented of a 62-year-old man diagnosed with synchronous lung and bladder cancer, who suddenly complained of numbness in the chin. The bone scan confirmed the suspicion of metastastic bone disease, and the patient died two months after the appearance of this sign.

Detection of bone metastases in breast cancer patients in the PET/CT era: Do we still need the bone scan?

AIM

To examine the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of bone metastasis in breast cancer patients and assess whether whole body bone scan (BS) with (99m)Tc-methylene diphosphonate provides any additional information.

MATERIAL AND METHODS

Study group comprised 150 patients, mean age 52 years (range 27-85) with breast cancer, suspected of having bone metastases. All patients had undergone both FDG-PET/CT and BS with or without single photon emission tomography/computed tomography (SPECT/CT) within a period of 6 weeks. The final diagnosis of bone metastasis was established by histopathological findings, additional imaging, or clinical follow-up longer than 10 months. Cancer antigen 15-3 (CA15-3) and carcinoembryogenic antigen (CEA) were measured in all patients.

RESULTS

Histologically 83%, 7% and 10% had infiltrating ductal, lobular and mixed carcinoma respectively. Confirmed bone metastases were present in 86 patients (57.3%) and absent in 64 (42.7%). Mean CA15-3 and CEA values in patients with bone metastases were 74.6ng/mL and 60.4U/mL respectively, compared to 21.3ng/mL and 3.2U/mL without metastases (p<0.001). The sensitivity of FDG-PET/CT for the detection of bone metastases was 97.6% compared to 89.5% with SPECT/CT. In 57 patients, FDG-PET/CT correctly identified additional pulmonary, hepatic, nodal and other soft tissue metastases, not detected by BS.

CONCLUSION

Our findings suggest that FDG-PET/CT is superior to BS with or without SPECT/CT.

[Diagnostic performance of bone scintigraphy and (11)C-Choline PET/CT in the detection of bone metastases in patients with biochemical recurrence of prostate cancer]

AIM

To compare bone scan (BS) with (11)C-Choline PET/CT for the detection of bone metastases in patients with biochemical recurrence of prostate cancer (PC).

MATERIAL AND METHODS

A total of 169 patients with biochemical recurrence of PC(PSA:2.4-58 ng/ml) who were referred for both exams (0-15 days-in-between) were included. Lesion-detection-rate per patients and lesions were analyzed for both BS and (11)C-Choline PET/CT. Metastasis diagnosis was reached by: biopsy, CT/(18)F-Fluoride PET/MRI confirmation, or evidence of progression in subsequent imaging procedures.

RESULTS

A total of 91 lesions were found to be active in BS and/or (11)C-choline PET/CT (40 patients), with 78 of which were metastatic. BS detected 38 blastic, 2 lytic and 10 non-CT-evident lesions. (11)C-Choline PET/CT detected 41 blastic, 4 lytic and 29 non-CT-evident lesions. BS and (11)C-Choline PET/CT sensitivities were 65.4% and 96.1%; specificities ere 38.5 and 92.3% (χ(2) 8.27, p<0.04). Both imaging techniques were negative in 118 patients. Tracer avid lesions were found in 51 patients: with 30/51 being BS and (11)C-Choline PET/CT concordant; in 21/51 patients had discordant lesions (kappa 0.712, p=0.00). Lesions were absolutely discordant in 10/19 patients,: 5 FN BS, 2 FP BS (degenerative changes; dysplasia), 1 FN (11)C-Choline PET/CT (blastic), 1 FP (11)C-Choline PET/CT (degenerative), 1 out of field-of-view lesion with (11)C-Choline PET/CT (tibia alone). (11)C-Choline PET/CT showed extraosseous involvement in 26/51 patients with bone metastases: 9 local recurrences, 5 infra-diaphragmatic-lymph-nodes, 2 supra-diaphragmatic, 5 local and infra-diaphragmatic, 4 infra- and supra-diaphragmatic, 1 supra-diaphragmatic and lung metastases.

CONCLUSION

(11)C-Choline PET/CT yielded better sensitivity and specificity than BS for the detection of bone involvement in patients with biochemical recurrence of PC and allowed extraosseous restaging, with an impact in the clinical management of these patients.

Bone scintigraphy and secondary osteomalacia due to nephrotoxicity in a chronic hepatitis B patient treated with tenofovir

Tenofovir is a nucleotide analogue used for the treatment of chronic hepatitis B and HIV infection. The safety of tenofovir is high but it has been described that tenofovir produces tubular toxicity and Fanconi's syndrome in some HIV-infected patients. To our knowledge this is the first documented case of bone involvement in Fanconi's syndrome in a patient treated with tenofovir for chronic hepatitis B without HIV coinfection. Bone scintigraphy has proven to be very useful for the diagnosis of secondary osteomalacia. Normalization of the bone scan after the withdrawal of the drug and the decline in alkaline phosphatase and phosphate serum levels reinforce the cause-effect relationship.

Predictors of bone metastasis in pre-treatment staging of asymptomatic treatment-naïve patients with prostate cancer

BACKGROUND

There is no general consensus on the optimal criteria for the application of bone scintigraphy in screening of bone metastasis in patients with prostate cancer. Our study was conducted to assess the value of bone scan for pre-treatment staging of asymptomatic treatment-naïve patients with prostate cancer.

METHODS

A total of 203 consecutive asymptomatic and treatment-naïve patients with prostate cancer (age: 67.6±6.4 years) who were referred to our department for whole body bone scintigraphy were enrolled in the study. Three hours after intravenous injection of 20mCi (99m)Tc-MDP, all patients underwent whole body bone scanning using a single head gamma camera. The planar images were supplemented with SPECT as needed for questionable abnormalities or those having uncertain location on planar images.

RESULTS

The mean serum PSA levels, serum alkaline phosphatase (ALP) and Gleason score (GS) were 42.41±37.1ng/ml, 223.9±129.9IU/L and 6.7±1.1, respectively. A total of 55 cases (27.1%) out of 203 patients had bone metastases. The univariate analysis showed that serum PSA levels, GS and ALP were all significant predictors of bone metastases. However, only serum PSA and ALP levels were found to be independent predictors of bone metastasis in the multivariate logistic regression analysis. The combination of PSA and ALP (in which patients with either elevated PSA [>20ng/ml] or elevated ALP were considered as positive) had the best screening value, with 98.2% sensitivity and 48.6% specificity.

CONCLUSION

Serum ALP screening can be employed as a tool to detect the subgroup of patients who are at high risk of bone metastases, while having a PSA of <20ng/ml. The combination of PSA and ALP can be used to improve predictability of bone metastasis in newly diagnosed patients with prostate cancer, without affecting staging accuracy.

[Multifocal epithelioid angiosarcoma of bone with lung metastases]

Angiosarcoma is a rare mesenchymal neoplasm that may arise from vascular or lymphatic tissue. Bone primary angiosarcoma is extremely rare, representing less than 1% of all angiosarcomas. It́s a very aggressive neoplasm and patients have metastatic disease at initial diagnosis in a large percentage of cases. On radiographs, these lesions are usually aggressive osteolytic lesions, commonly with soft-tissue mass extension, and tumoral enhancement on CT or MR imaging. The appearance of the bone scan is variable, describing studies with tracer uptake or low uptake. These tumours are more often found in the long bones, but spinal involvement has been reported in 10% of patients. There are a few reports in the literature of bone angiosarcoma with lung metastases. We present a patient with multifocal epithelioid angiosarcoma (spine and ribs) and multiple lung metastasis, evidenced by CT and conventional bone scintigraphy, with a fast growth.