Quantitative bone single photon emission computed tomography/computed tomography in symptomatic and asymptomatic foot and ankle osteoarthritis.

PURPOSE: The purpose of this study was to evaluate and quantify the prevalence of increased uptake in SPECT/CT in symptomatic and asymptomatic foot and ankle joints in patients with osteoarthritis. METHODS: In 63 patients with osteoarthritis (OA), the painful symptomatic foot (SF) and asymptomatic contralateral foot (AF) were imaged with bone SPECT/CT. Presence, localization, and maximum standardized uptake value (SUVmax) of the active joints were assessed for SF and AF. CT OA grade (grade 1: mild, grade 2: moderate, grade 3: severe) and presence of five morphological features of OA (joint space narrowing, subchondral sclerosis, subchondral cysts, irregular joint margins, and osteophytes) were evaluated. RESULTS: In total 32 (51%) patients showed additional uptake in the AF, whereas 31 (49%) patients showed it only in the SF. SF showed more active joints than AF (106 vs. 43). CT OA grades positively correlated with SUVmax (Kendall's tau b = 0.62, P < 0.001). SUVmax values (per foot) in SF were higher in patients with uptake in bilateral feet (SF+, AF+) [median (IQR): 17.9 (10.7-23.3)] as compared with patients with active sites only in the SF (SF+, AF-) [10.4 (6.4-19.1); P < 0.001]. Number of active OA joints in SF was higher in patients with bilateral uptake (P = 0.017). CONCLUSION: In conclusion, half of the patients exhibited increased uptake in the contralateral asymptomatic foot. SUVmax showed a significant correlation to CT osteoarthritis grade, in the symptomatic and asymptomatic foot. Future follow-up studies will provide further insights into the prognostic and therapeutic value of these findings.

Pulmonary Amyloidoma Imitating Lung Cancer on 18 F-FDG PET/CT.

ABSTRACT: Localized pulmonary amyloidosis forming a solitary mass known as "amyloidoma of the lung" is rare. Differentiation from lung cancer can be difficult due to suspicious features on CT and high 18 F-FDG uptake. We present a case of a 77-year-old woman with an incidental lung lesion on abdominal CT. Further evaluation with chest CT and 18 F-FDG PET/CT maintained the suspicion of lung cancer. However, histology revealed amyloidoma without signs of malignancy. Knowledge of imaging similarities between pulmonary amyloidomas and malignancies is important for interpreting 18 F-FDG PET/CT of lung tumors; however, only biopsy can confirm the rare differential diagnosis such as pulmonary amyloidoma.

The value of bone SPECT/CT in evaluation of foot and ankle arthrodesis and adjacent joint secondary osteoarthritis.

OBJECTIVE: To evaluate the value of SPECT/CT (single photon emission computed tomography/computed tomography) in foot and ankle arthrodesis and development of secondary osteoarthritis in the adjacent joints. MATERIALS AND METHODS: SPECT/CT of 140 joints in the foot and ankle (34 upper ankle (UA), 28 lower ankle (LA), 27 talonavicular (TN), 12 calcaneo-cuboidal (CC), and 39 other smaller joints after arthrodesis in 72 patients were evaluated retrospectively regarding fusion grade in CT (0 = no fusion, 1 = < 50% fusion, 2 = > 50% fusion, 3 = complete fusion) and radiotracer uptake (0 = no uptake, 1 = mild uptake, 2 = moderate uptake, 3 = high uptake) on SPECT/CT. Severity of osteoarthritis (1 = mild, 2 = moderate, 3 = severe) and radiotracer uptake grade in adjacent joints was also assessed. In 54 patients, clinical information about interventions in the follow-up was available. RESULTS: According to the SPECT/CT, arthrodesis was successful (grade 2 or 3 CT fusion and grade 0 or 1 uptake) in 73% (25/34) of UA joints, 71% (20/28) of LA joints, 67% (18/27) TN, 100% (12/12) CC joints, and 62% (24/39) of other smaller joints. In 12 joints, there were discrepant findings in SPECT/CT (fusion grade 2 and uptake grade 2 or 3 (n = 9); or, fusion grade 0 or 1 and uptake grade 1 (n = 3)). The fusion rate 6-12 months after arthrodesis was 42% (14/33), 59% (20/34) after 13-24 months, and 89% (65/73) after more than 24 months, respectively. Average radiotracer uptake in arthrodesis decreased with age: 6-12 months: 1.60, 12-24 months: 1.32, > 24 months: 0.38. There was a significant negative correlation between radiotracer uptake grade and CT fusion grade. Osteoarthritis was observed in 131 adjacent joints. During the post scan follow-up, additional arthrodeses were performed in 33 joints, of which 11 joints were re-arthrodesis and 22 were new arthrodeses in osteoarthritic adjacent joints. All these 11 joints with failed arthrodesis had grade 0 of CT fusion and grade 2 or 3 of radiotracer uptake. All 22 adjacent joints with osteoarthritis, which subsequently underwent arthrodesis, had grade 2 or 3 radiotracer uptake, and the primary arthrodesis joints were healed and fused in all these cases. CONCLUSION: Bone SPECT/CT is a valuable hybrid imaging tool in the evaluation of foot and ankle arthrodesis and gives additional useful information about the development of secondary osteoarthritis in the adjacent joints with higher value for the assessment of secondary osteoarthritis. A practical four-type classification ('Lucerne Criteria') combining metabolic and morphologic SPECT/CT information for evaluation of arthrodesis joints has been proposed.

Incorporation of CAD (computer-aided detection) with thin-slice lung CT in routine 18F-FDG PET/CT imaging read-out protocol for detection of lung nodules.

OBJECTIVE: To evaluate the detection rate and performance of 18F-FDG PET alone (PET), the combination of PET and low-dose thick-slice CT (PET/lCT), PET and diagnostic thin-slice CT (PET/dCT), and additional computer-aided detection (PET/dCT/CAD) for lung nodules (LN)/metastases in tumor patients. Along with this, assessment of inter-reader agreement and time requirement for different techniques were evaluated as well. METHODS: In 100 tumor patients (56 male, 44 female; age range: 22-93 years, mean age: 60 years) 18F-FDG PET images, low-dose CT with shallow breathing (5 mm slice thickness), and diagnostic thin-slice CT (1 mm slice thickness) in full inspiration were retrospectively evaluated by three readers with variable experience (junior, mid-level, and senior) for the presence of lung nodules/metastases and additionally analyzed with CAD. Time taken for each analysis and number of the nodules detected were assessed. Sensitivity, specificity, positive and negative predictive value, accuracy, and Receiver operating characteristic (ROC) analysis of each technique was calculated. Histopathology and/or imaging follow-up served as reference standard for the diagnosis of metastases. RESULTS: Three readers, on an average, detected 40 LN in 17 patients with PET only, 121 LN in 37 patients using ICT, 283 LN in 60 patients with dCT, and 282 LN in 53 patients with CAD. On average, CAD detected 49 extra LN, missed by the three readers without CAD, whereas CAD overall missed 53 LN. There was very good inter-reader agreement regarding the diagnosis of metastases for all four techniques (kappa: 0.84-0.93). The average time required for the evaluation of LN in PET, lCT, dCT, and CAD was 25, 31, 60, and 40 s, respectively; the assistance of CAD lead to average 33% reduction in time requirement for evaluation of lung nodules compared to dCT. The time-saving effect was highest in the less experienced reader. Regarding the diagnosis of metastases, sensitivity and specificity combined of all readers were 47.8%/96.2% for PET, 80.0%/81.9% for PET/lCT, 100%/56.7% for PET/dCT, and 95.6%/64.3% for PET/CAD. No significant difference was observed regarding the ROC AUC (area under the curve) between the imaging methods. CONCLUSION: Implementation of CAD for the detection of lung nodules/metastases in routine 18F-FDG PET/CT read-out is feasible. The combination of diagnostic thin-slice CT and CAD significantly increases the detection rate of lung nodules in tumor patients compared to the standard PET/CT read-out. PET combined with low-dose CT showed the best balance between sensitivity and specificity regarding the diagnosis of metastases per patient. CAD reduces the time required for lung nodule/metastasis detection, especially for less experienced readers.

Review of the role of bone-SPECT/CT in tarsal coalitions.

Tarsal coalition (TC) is a congenital abnormal connection (fibrous, cartilaginous, or osseous) between two or more bones in the hind and midfoot, mostly consisting of calcaneonavicular or talocalcaneal coalition, and is often asymptomatic. However, TCs may result in foot motion limitation and pain with or without flatfoot (pes planus), arising in adolescents and young adults. Appropriate imaging is needed to pinpoint foot pain in the (suspected) TC, starting with plain radiographs. Still, normal radiographs do not exclude TCs. Computed tomography (CT) and MRI are frequently used advanced imaging techniques. CT alone has known limited sensitivity in cartilaginous and fibrous TCs and correlation between CT abnormalities and pain may be challenging, as solely anatomical changes in TCs are often asymptomatic. MRI can depict soft tissue abnormalities in TC with high accuracy. Nonetheless, after the implantation of metallic osteosynthesis material, MRI is often limited due to image distortion, signal loss, and misregistration. Bone scintigraphy with [99mTc]Tc-diphosphonate single photon emission computed tomography/CT (bone-SPECT/CT) is a known sensitive tool to detect osteoblastic bone pathology. However, the literature concerning bone-SPECT/CT in TC patients is limited. This article reviews bone-SPECT/CT patterns in TCs, how it complements other imaging techniques and their relation to clinical complaints. Bone-SPECT/CT excels in accurate bone pathology characterization in TC, confidently excluding synchronous lesions elsewhere, and offering optimal insight into osseous structures and 3D-localization of bone metabolism for surgery planning. Furthermore, even with implanted osteosynthesis material, bone-SPECT/CT can pinpoint the culprit pain generator, where MRI is either contra-indicated or considerably hampered.

Long-term, real world experience of ventricular tachycardia and granulomatous cardiomyopathy.

BACKGROUND: Granulomatous cardiomyopathy (GCM) is relatively uncommon in patients presenting with ventricular tachycardia (VT). Sarcoidosis and tuberculosis are the most common causes of GCM with VT. The aim of study was to evaluate their clinical characteristics and the long-term outcomes. METHODS: We retrospectively analyzed patients from March 2004 to January 2020, presenting with VT and subsequently diagnosed to have GCM. Patients were divided into three groups (sarcoid, tuberculosis and indeterminate) based on serologic tests, imaging and histopathology. The response to anti-arrhythmic and disease specific therapy on long-term follow-up were analyzed. RESULTS: There were 52 patients, comprising 27 males and 25 females, age 40 ± 10 years. The follow-up period was 5.9 ± 3.9 years. Sarcoidosis was diagnosed in 20 (38%); tuberculosis (TB) in 15(29%) and 17(33%) patients were indeterminate. Left ventricular ejection fraction (LVEF) of the entire cohort was 0.45 ± 0.14. Erythrocyte Sedimentation Rate(ESR) was found to be significantly higher in TB(43.6 ± 18.4) patients vs sarcoid(18.9 ± 6.7)p < 0.0001, but not the indeterminate group (36.2 ± 21.1), p = 0.3. Implantable Cardioverter Defibrillator (ICD) implantation was performed in 12/20(60%) patients in the sarcoid group, in 4/15(27%) patients in the TB group and in 10/17(59%) patients in the indeterminate group. At a mean follow-up of six years, VT recurrences were noted in 6, 2, and 7 patients in the sarcoid, TB and indeterminate groups respectively. CONCLUSION: Despite the advances in diagnostic modalities for tuberculosis and sarcoidosis, in real-world practice, almost one-third of the patients with VT and GCM have uncertain etiology. Long term outcomes of patients presenting with GCM and VT with mild left ventricle dysfunction treated appropriately seems favorable.

Monitoring jaw osteomyelitis therapy with single-photon emission computed tomography/computed tomography.

OBJECTIVE: The aim of the study was to evaluate the value of single-photon emission computed tomography/computed tomography (SPECT/CT) for therapy response assessment of jaw osteomyelitis. MATERIALS AND METHODS: Thirty-four baseline and 74 follow-up SPECT/CT examinations for therapy response assessment were performed in 34 patients with jaw osteomyelitis. SPECT/CT and planar late-phase bone scintigraphy images were assessed at baseline and follow-up, according to the following criteria: tracer uptake grade (0 = no uptake, 1 = low uptake, 2 = moderate uptake and 3 = high uptake); and morphologic signs (osteolysis, sequestration, sclerosis, periosteal reaction and pathologic fracture). RESULTS: At baseline, SPECT/CT showed marked (grade 2 or 3) uptake in 91% (31/34) of the patients, osteolysis in 85% (29/34), sclerosis in 71% (24/34), periosteal reaction in 44% (15/34) and a sequestrum in 24% (8/34). In 24 patients with clinically complete remission during or after at least 12 months' therapy, bone scintigraphy showed grade 0 or 1 uptake in 100% (24/24) and SPECT/CT in 91% (22/24) of the patients. Sclerosis with the disappearance of osteolysis, sequestration and periosteal reactions was the predominant morphologic finding in complete responders (68%; 16/24). In 10 patients with symptoms of exacerbation of the osteomyelitis, 80% (8/10) showed increasing uptake, 90% (9/10) sclerosis, 80% osteolysis (8/10) and 40% (4/10) osteolysis and periosteal reactions. CONCLUSION: SPECT/CT is a valuable tool to accurately assess therapy response, disease exacerbation and complications of jaw osteomyelitis. Low-grade (grade 1) residual tracer uptake is common in patients with clinically complete remission and is suggestive of ongoing bone remodeling and healing.

Performance of radiography and single-photon emission computed tomography/computed tomography in painful total hip arthroplasty and impact on arthroplasty survival.

PURPOSE: To investigate the performance of radiography and single-photon emission computed tomography/computed tomography (SPECT/CT) in painful hip arthroplasty regarding loosening and arthroplasty survival. METHODS: Radiography and SPECT/CT reports of 249 painful hip arthroplasties of 191 patients were reviewed. Positive imaging was defined if loosening, infection, and polyethylene wear were found, indicating the need for arthroplasty exchange. Median time from radiograph to operation or last follow-up was 41.3 months (range 0.3-118.4 months). In 67 patients, the performance of radiographs and SPECT/CT regarding loosening was compared with an intraoperative reference standard. The time point of arthroplasty exchange was compared with imaging diagnosis and evaluated with Kaplan-Meier curves. RESULTS: Exchange of cup, shaft, or both was performed in 76 of 249 arthroplasties. Main diagnoses on SPECT/CT were loosening (n = 94), infection (n = 5), and polyethylene wear (n = 15). In total, 104 patients were SPECT/CT positive compared to 84 patients on radiography. Five-year survival of arthroplasties for radiograph positive and negative arthroplasties was 41.5%/83.4% and 39.3%/90.7% for SPECT/CT, respectively. Prognostic impact regarding arthroplasty exchange was highest in radiograph and SPECT/CT concordant positive patients (hazard ratio 19.7 as compared to radiograph and SPECT/CT negative patients). Sensitivity and specificity in 67 operated patients regarding shaft loosening were 59.4%/80.0% with radiography, 90.6%/68.6% with SPECT/CT (P = 0.002 for sensitivity and P = 0.29 for specificity), and for cup loosening 47.4%/89.6% with radiography and 63.2%/85.4% with SPECT/CT (P = 0.51, respectively, P = 0.63). CONCLUSION: In patients with painful hip arthroplasty, positive radiography, and SPECT/CT are associated with poorer arthroplasty survival. Performance regarding loosening is slightly better with SPECT/CT.

Value of SPECT/CT in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures.

OBJECTIVE: To evaluate the value of single-photon emission computed tomography / computed tomography (SPECT/CT) compared with planar bone scintigraphy (BS) in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic fractures. METHODS: Retrospective evaluation of patients with traumatic fractures and suspected delayed healing or non-union and/or persistent pain or suspected infection who had undergone planar late phase BS and SPECT/CT between 2011 and 2018. On the BS and SPECT/CT images, a necrotic fragment was considered if there was an area of absent radiotracer uptake (photopenia) related to bone at the fracture site. Histology served as a reference standard (presence or absence of necrotic bone fragments). If histology was not available, intraoperative findings and combined clinical and imaging follow-up served as reference standards. RESULTS: In 37 consecutive patients with traumatic fractures (femur (n = 18), tibia (11), humerus (6), radius (1), jaw (1)), necrotic bone fragments were suspected in 11 fractures (29.7%) on BS and in 16 fractures (43.2%) on SPECT/CT. 35 fractures (94.6%) had metallic implants. Histology showed necrotic fragments in 10/11 (90.9%) patients. For the detection of necrotic bone fragments, SPECT/CT showed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 100%, 95%, 94%, 100%, and 97%, respectively, and BS 67%, 95%, 91%, 81%, and 83%, respectively. SPECT/CT significantly outperformed BS with better area under curve (AUC) for SPECT/CT (0.9773) compared to planar imaging (0.8106) (p-value < 0.01). CONCLUSIONS: SPECT/CT is an accurate tool in the assessment of necrotic bone fragments in patients with delayed bone healing or non-union after traumatic bone fractures and is superior to conventional planar BS. ADVANCES IN KNOWLEDGE: SPECT/CT is accurate and superior to planar BS in identification of necrotic bone fragments, responsible for delayed bone healing/non-union after fractures.

Single-photon emission computed tomography/computed tomography arthrography of wrist, ankle, and knee joints.

OBJECTIVE: To evaluate the additional value of single-photon emission computed tomography/computed tomography arthrography compared with single-photon emission computed tomography/computed tomography alone in wrist, ankle, and knee joints. MATERIALS AND METHODS: Retrospective evaluation of 68 patients including 74 joints (48 wrists, 13 upper ankle (talocrural joint), and 13 knee joints) was performed. Activity in single-photon emission computed tomography/computed tomography images was graded using a four-point scale: 0 no uptake, one low uptake, two moderate uptake, and three high uptake. Arthrography images were evaluated for the presence of cartilage/ligament/meniscal lesions, and loose bodies. RESULTS: Fifty-six joints (76%) showed increased activity in late planar and 58 (78%) in single-photon emission computed tomography/computed tomography images, the latter graded as follows: grade 1 in 20 (34%), grade 2 in 29 (50%), grade 3 in nine (16%) joints. 16 joints were inactive (grade 0) in single-photon emission computed tomography/computed tomography. In 57 joints (77%), intraarticular contrast unmasked additional pathologies (37 cartilage lesions, 25 ligaments tears, 25 triangular fibrocartilage complex tears, six meniscal lesions, and four loose bodies). There was matching findings between single-photon emission computed tomography and computed tomography arthrography in 57 joints (77%) and mismatching findings in 17 joints (23%). Out of these 17 mismatched joints, eight were metabolically inactive but showed some lesion in computed tomography arthrography, whereas nine metabolically active joints did not show any abnormality in computed tomography arthrography. CONCLUSION: The addition of arthrography to single-photon emission computed tomography/computed tomography of wrist, ankle, and knee joints leads to supplementary visibility of lesions of cartilage, ligaments, triangular fibrocartilage complex, meniscus, or loose bodies in 77% of joints. Single-photon emission computed tomography/computed tomography arthrography can serve as promising alternative especially in patients with magnetic resonance imaging contraindications or metallic hardware.

Impact of metal implants on xSPECT/CT Bone reconstruction: the "shining metal artefact".

BACKGROUND: Novel reconstruction algorithms, such as xSPECT Bone, are gaining more and more importance in Nuclear Medicine. With xSPECT Bone, the reconstructed emission image is enhanced by the information obtained in the corresponding CT image. The CT defines tissue classes according to the Hounsfield units. In the iterative reconstruction, each tissue class is handled separately in the forward projection step, and all together in the back projection step. As a consequence, xSPECT Bone reconstruction generates images with improved boundary delineation and better anatomic representation of tracer activity. Applying this technique, however, showed that artefacts may occur, when no uptake regions, like metal implants, exhibit fictitious uniform tracer uptake. Due to limitations in spatial resolution in gamma cameras, the xSPECT Bone reconstructed image resulted in spill-out activity from surrounding high uptake region being uniformly distributed over the metal implants. This new technology of xSPECT Bone reconstruction in general enhances the image quality of SPECT/CT; however, the potential introduction of specific artefacts which inadvertently come along with this new technology and their frequency have not yet been addressed in the literature. Therefore, the purpose of this work was to identify and characterize these specific metal artefacts (the so-called shining metal artefact) in order to reduce false positives and avoid potentially misdiagnosing loosened or infected implants. CASE PRESENTATION: In this work, we report five cases imaged with bone SPECT/CT of 5 anatomical regions (foot, elbow, spine, shoulder, ribs and knee). All cases demonstrated "shining metal artefacts" in xSPECT Bone reconstruction. CONCLUSION: While xSPECT Bone reconstruction algorithm significantly improves image quality for the diagnosis of bone and joint disorders with SPECT/CT, specific "shining metal artefacts" caused by the xSPECT Bone have to be recognized in order to avoid image misinterpretation suggesting metallic implant loosening or possible infection. The simultaneous analysis of conventionally reconstructed SPECT images (for Siemens the Flash3D reconstruction) helps to avoid misinterpretation of potential artefacts introduced by xSPECT Bone reconstruction.

Magnetic resonance imaging (MRI) versus single photon emission computed tomography (SPECT/CT) in painful total hip arthroplasty: a comparative multi-institutional analysis.

OBJECTIVE: To investigate the value of MRI in comparison to single photon emission computed tomography (SPECT)/CT in patients with painful hip arthroplasties. METHODS: A prospective, multi-institutional study was performed. Therefore, 35 consecutive patients (21 female, 14 male, mean age 61.8 ± 13.3 years) with 37-painful hip arthroplasties were included. A hip surgeon noted the most likely diagnosis based on clinical examination and hip radiographs. Then, MRI and SPECT/CT of the painful hips were acquired. MRI and SPECT/CT were assessed for loosening, infection, fracture, tendon pathology and other abnormalities. Final diagnosis and therapy was established by the hip surgeon after integration of MRI and SPECT/CT results. The value of MRI and SPECT/CT for diagnosis was assessed with a 3-point scale (1 = unimportant, 2 = helpful, 3 = essential). RESULTS: Loosening was observed in 13/37 arthroplasties (6 shaft only, 6 cup only, 1 combined). Sensitivity, specificity, positive predictive value and negative predictive value for loosening of MRI were 86%/88%/60%/100% and of SPECT/CT 93%/97%/90%/100%, respectively. MRI and SPECT/CT diagnosed infection correctly in two of three patients and fractures in two patients, which were missed by X-ray. MRI detected soft tissue abnormalities in 21 patients (6 bursitis, 14 tendon lesions, 1 pseudotumor), of which only 1 tendon abnormality was accurately detected with SPECT/CT. All 5 arthroplasties with polyethylene wear were correctly diagnosed clinically and with both imaging modalities. MRI and SPECT/CT were judged as not helpful in 0/0%, as helpful in 16%/49% and essential in 84%/51%. CONCLUSION: In patients with painful hip arthroplasty SPECT/CT is slightly superior to MR in the assessment of loosening. MRI is far superior in the detection of soft tissue, especially tendon pathologies. ADVANCES IN KNOWLEDGE: To our knowledge this is the first prospective, multiinstitutional study which compares MRI with SPECT/CT in painful hip arthroplasties. We found that MRI is far superior in the detection of soft tissue pathologies, whereas SPECT/CT remains slightly superior regarding loosening.

SPECT/CT Findings in Scapular Notching After Reverse Shoulder Arthroplasty.

Scapular notching (SN) is a unique complication in reverse shoulder arthroplasty, caused by repetitive impingement of the humeral polyethylene liner against the inferior scapular neck. It occurs in up to 96% of cases, with bone loss beneath the glenoid baseplate and polyethylene wear. SN can be associated with pain, decreased range of motion, and might result in glenoid implant failure. Modification of glenosphere design and humeral neck angle showed substantially less SN. SPECT/CT is a promising tool providing combined morphologic and metabolic information in symptomatic SN. We present SPECT/CT findings in 7 cases of symptomatic SN in reverse shoulder arthroplasty patients.

Osteoid osteoma: multimodality imaging with focus on hybrid imaging.

Osteoid osteoma is a painful, benign, osteoblastic lesion that occurs in younger patients and affects the extremities or the axial skeleton. While plain film findings may suggest the diagnosis, in complex anatomical regions such as the spine, pelvis, wrist and foot advanced imaging modalities are often required. A typical nidus surrounded by sclerosis or cortical thickening characterizes osteoid osteoma on plain radiography and CT. MR is the cross-sectional imaging modality of choice for most musculoskeletal disorders. Unfortunately, extensive accompanying bone marrow oedema, soft-tissue alterations, difficulty detecting the nidus, and lesion locations close to a joint (with reactive arthritis) may make a confident diagnosis of osteoid osteoma by MR imaging difficult. Hybrid imaging with bone-seeking tracers such as SPECT/CT with 99mTc-labelled bisphosphonates or PET/CT with 18F-labelled sodium fluoride (18F-NaF) combines high radionuclide uptake with morphological details and provides accurate diagnosis of osteoid osteoma and additional information for treatment planning. FDG is not the recommended PET tracer because osteoid osteoma is normally FDG-negative, although some osteoid osteomas may show increased FDG uptake. Osteoblastoma, Brodie's abscess and stress fractures may mimic osteoid osteoma on imaging and clinical presentation. Once identified as the pain generator, destruction of the osteoid osteoma nidus by ablation or resection techniques usually leads to complete healing. Image-guided drill excision and radiofrequency ablation are widely used interventions. We review the presentation of osteoid osteoma across all imaging modalities, with special focus on hybrid imaging techniques.

SPECT/CT arthrography.

Single photon emission CT (SPECT)/CT arthrography, the combination of CT arthrography and late phase bone SPECT/CT, has been developed in 2011 and so far used in knee, ankle and wrist joints. SPECT/CT offers functional information about increased bone turnover in combination with morphological details. Compared with SPECT/CT alone, additional intra-articular contrast enables the assessment of cartilage, menisci, ligaments and loose bodies. SPECT/CT arthrography is a promising alternative technique for the evaluation of internal derangement of joints in patients with MR contraindications and/or metallic implants. In this article, we review and report our 5-year experience with this technique illustrated with patient examples and give a perspective for future applications.

The value of ultrasound-guided biopsy of fluorodeoxy-glucose positron emission tomography (FDG-PET)-positive supraclavicular lymph nodes in patients with suspected lung cancer.

BACKGROUND: Accurate lymph node staging is essential for adequate prognostication and therapy planning in patients with non-small cell lung cancer (NSCLC). FDG-PET/CT is a sensitive tool for the detection of metastases, including non-palpable supraclavicular lymph node (SCLN) metastases. Histological proof of metastatic spread and mutation analysis is crucial for optimal staging and therapy. The aim of this study was to investigate the value of ultrasound-guided fine needle aspiration cytology (FNAC) and core biopsy (CB) of FDG active, non-palpable SCLN's in patients with suspicion for lung cancer. METHODS: Twelve consecutive patients with suspected lung cancer and FDG-positive SCLN underwent FNAC (n = 11) and/or CB (n = 10) and were included and evaluated retrospectively in this study. Cytologic and/or histologic evaluation was performed to confirm initially suspected diagnosis (lung cancer), to confirm N3 stage, and to screen for driver mutations in lung adenocarcinoma. RESULTS: FNAC alone showed diagnostic success in 11/11 cases (100%), CB alone in 9/10 patients (90%), and the combination of both procedures was successful in 12/12 cases (100%). Lymph node metastases from NSCLC (7 adenocarcinoma, 2 squamous cell carcinoma) could be confirmed in 9 patients. Other diagnoses were small cell lung cancer (SCLC), breast cancer and sarcoidosis. There was enough material for immunhistochemistry in all patients. For molecular testing, material from this lymph node biopsies and lung biopsy was used. In two patients with adenocarcinoma of the lung driver mutations were detected (EGFR Exon 19 deletion and ALK rearrangement) out of the lymph node metastasis. CONCLUSIONS: US-guided combined FNAC and CB of FDG positive supraclavicular lymph nodes in patients with suspected lung cancer is a safe and effective procedure to confirm N3-stage and to obtain representative material for molecular testing.

The value of SPECT/CT in carpal boss.

PURPOSE: To assess the value of SPECT/CT in patients with carpal boss (CB). METHODS: In 24 wrists with CB (18 right-sided, 6 left-sided) in 21 patients, planar images and SPECT/CT images were obtained. Three patients had bilateral CB. The grade of uptake (0 absent, 1 low, 2 moderate, 3 high) on planar imaging and SPECT/CT was assessed and compared with CT findings, clinical symptoms and follow-up findings. RESULTS: CB affected carpometacarpal joint II in 4 wrists, carpometacarpal joint III in 17 wrists and both carpometacarpal joints II and III in 3 wrists. Of the 24 CB, 12 (50 %) were active (i.e. increased radionuclide uptake) on planar images and 18 (75 %) on SPECT/CT images. Of the 17 symptomatic CB, 10 (59 %) were active on planar images and 14 (82 %) were active (mean grade 1.9, range 1 - 3) on SPECT/CT images. Of the 7 asymptomatic CB, 2 were active on planar images and 4 were active (mean grade 1.25, range 1 - 2) on SPECT/CT images. CT alone showed CB in all patients and an accessory ossicle (os styloideum) in 8 wrists. MR imaging was available in 7 patients and positive for CB in 5 (sensitivity 71 %). Plain radiographs were available in 17 patients and positive in 10 (59 %). Therapeutic infiltration of the CB was performed in 9 patients, and resection of the CB in 7 patients. CONCLUSION: SPECT/CT provides important morphological and metabolic information for the clinical assessment of CB, but because SPECT/CT tends to overestimate the clinical importance of CB, we recommend that planar images should still be obtained.

Intrapancreatic Accessory Spleen Mimicking Neuroendocrine Tumor on 68Ga-DOTATATE PET/CT.

Besides well-known physiologic uptake of Ga-DOTATATE in spleen, pituitary gland, pancreatic head, adrenals, kidney, and urinary bladder, sometimes unusual areas of uptake are found. We report a case of a 53-year-old woman who had vague pain in abdomen for which abdominal CT was done showing a contrast-enhancing lesion in the pancreatic tail. It was suspected to be of neuroendocrine origin and Ga-DOTATATE PET/CT showed a corresponding focal uptake. Spleen-preserving pancreatic tail resection was performed. Pathology revealed the diagnosis of an accessory intrapancreatic spleen (AIPS).