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.

Increased 18F-PSMA and 18F-FDG Uptake in Lipomatous Hypertrophy of the Interatrial Septum.

ABSTRACT: Lipomatous hypertrophy of the interatrial septum (LHIS) is a benign anomaly with low prevalence. Lipomatous hypertrophy of the interatrial septum is asymptomatic in most of the cases and rarely leads to atrial arrhythmias, obstructive flow symptoms, or sudden death. It is mostly diagnosed as an incidental finding in cross-sectional imaging and echocardiography, and increased 18F-FDG uptake on LHIS has been described. We present a case of repeated increased 18F-PSMA uptake in LHIS. Although very rare, familiarity with the typical features and prevalence of LHIS in PET/CT can avoid misinterpretation for metastatic disease.

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.

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.

Feasibility and preliminary results of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction.

PURPOSE: To evaluate the feasibility and performance of SPECT/CT arthrography of the wrist in comparison with MR arthrography in patients with suspected ulnocarpal impaction. METHODS: This prospective study included 28 wrists of 27 patients evaluated with SPECT/CT arthrography and MR arthrography. Iodine contrast medium and gadolinium were injected into the distal radioulnar and midcarpal joints. Late-phase SPECT/CT was performed 3.5 h after intravenous injection of approximately 650 MBq (99m)Tc-DPD. MR and SPECT/CT images were separately reviewed in relation to bone marrow oedema, radionuclide uptake, and tears in the scapholunate (SL) and lunotriquetral (LT) ligaments and triangular fibrocartilage complex (TFCC), and an overall diagnosis of ulnar impaction. MR, CT and SPECT/CT imaging findings were compared with each other, with the surgical findings in 12 patients and with clinical follow-up. RESULTS: The quality of MR arthrography and SPECT/CT arthrography images was fully diagnostic in 23 of 28 wrists (82%) and 25 of 28 wrists (89%), respectively. SPECT/CT arthrography was not diagnostic for ligament lesions due to insufficient intraarticular contrast in one wrist. MR and SPECT/CT images showed concordant findings regarding TFCC lesions in 22 of 27 wrists (81%), SL ligament in 22 of 27 wrists (81%) and LT ligament in 23 of 27 wrists (85%). Bone marrow oedema on MR images and scintigraphic uptake were concordant in 21 of 28 wrists (75%). MR images showed partial TFCC defects in four patients with normal SPECT/CT images. MR images showed bone marrow oedema in 4 of 28 wrists (14%) without scintigraphic uptake, and scintigraphic uptake was present without MR bone marrow oedema in three wrists (11%). Regarding diagnosis of ulnar impaction the concordance rate between CT and SPECT/CT was 100% and reached 96% (27 of 28) between MR and SPECT/CT arthrography. The sensitivity and specificity of MR, CT and SPECT/CT arthrography were 93%, 100% and 100%, and 93%, 93% and 93%, respectively. CONCLUSION: SPECT/CT arthrography of the wrist is feasible. Regarding diagnosis of ulnar impaction we found a high concordance with MR arthrography. SPECT/CT arthrography of the wrist is an alternative to MR arthrography in patients with contraindications to MR imaging.