The role of SPECT/CT in painful, noninfected knees after knee arthroplasty: a systematic review and meta-analysis-a diagnostic test accuracy review.

PURPOSE: The aim of this systematic review was to present the current evidence on the clinical use of single-photon emission computed tomography/computed tomography (SPECT/CT) in the evaluation of noninfected painful knees after knee arthroplasty. METHODS: Embase, PubMed, Google Scholar, Ovid, Scopus, Science Direct and the Cochrane Database of Systematic Reviews were searched from database inception to May 2022 following the PRISMA guidelines. As a primary outcome, we defined the role of SPECT/CT in the diagnostic approach to noninfected painful knee arthroplasty; as a secondary objective, we described the noninfection-related factors linked to painful knee arthroplasty. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio values and other indicators were calculated; receiver operating characteristic (ROC) curve analysis results and a summary of the areas under the curve (AUCs) from the included studies were reported. A Fagan plot, likelihood ratio plot and Deeks' funnel plot were generated and analysed. Methodological quality was assessed using the QUADAS-2 tool, and the certainty of evidence was assessed by the GRADE approach. RESULTS: A total of 493 publications were identified, of which eight met the inclusion criteria, with a final pooled sample size of 308 patients. The pooled sensitivity and specificity of SPECT/CT in diagnosing the source of pain in painful knee prostheses were 0.86 (95% CI: 0.75-0.93) and 0.90 (95% CI: 0.79-0.96), respectively, with pooled +LR and -LR values of 8.9 (95% CI: 4.11-19.19) and 0.15 (95% CI: 0.09-0.28). The pooled diagnostic odds ratio was 57.35, and the area under the curve was 0.94. SPECT/CT highly accurately identified different sources of pain, such as loosening of the prosthetic components, patellofemoral overloading, instability, malalignment of the components and degeneration of the patellofemoral compartment. The confidence of the estimates was moderate according to the GRADE approach. CONCLUSION: With demonstrated high sensitivity and specificity, as a diagnostic tool, SPECT/CT can identify the source of pain in painful knees after knee arthroplasty, particularly in cases of loosening, patellofemoral disorders and component malalignment (level of evidence III). These findings have significant clinical repercussions, such as in changing the initial diagnosis, identifying or excluding different causes of painful knee arthroplasties, guiding subsequent treatment and positively impacting the final clinical outcome. We moderately recommend the use of SPECT/CT for identifying the source of pain after knee arthroplasty according to the GRADE assessment. This review was preregistered in Prospero under code CRD42022320457.

Correlations of typical pain patterns with SPECT/CT findings in unhappy patients after total knee arthroplasty.

PURPOSE: The diagnostic process in patients after painful total knee arthroplasty (TKA) is challenging. The more clinical and radiological information about a patient with pain after TKA is included in the assessment, the more reliable and sustainable the advice regarding TKA revision can be. The primary aim was to investigate the position of TKA components and evaluate bone tracer uptake (BTU) using pre-revision SPECT/CT and correlate these findings with previously published pain patterns in painful patients after TKA. METHODS: A prospectively collected cohort of 83 painful primary TKA patients was retrospectively evaluated. All patients followed a standardized diagnostic algorithm including 99m-Tc-HDP-SPECT/CT, which led to a diagnosis indicating revision surgery. Pain character, location, dynamics and radiation were systematically assessed as well as TKA component position in 3D-CT. BTU was anatomically localized and quantified using a validated localization scheme. Component positioning and BTU were correlated with pain characteristics using non-parametric Spearman correlations (p < 0.05). RESULTS: Based on Spearman's rho, significant correlations were found between pain and patients characteristics and SPECT/CT findings resulting in nine specific patterns. The most outstanding ones include: Pattern 1: More flexion in the femoral component correlated with tender/splitting pain and patella-related pathologies. Pattern 3: More varus in the femoral component correlated with dull/heavy and tingling/stinging pain during descending stairs, unloading and long sitting in patients with high BMI and unresurfaced patella. Pattern 6: More posterior slope in the tibial component correlated with constant pain. CONCLUSION: The results of this study help to place component positioning in the overall context of the "painful knee arthroplasty" including specific pain patterns. The findings further differentiate the clinical picture of a painful TKA. Knowing these patterns enables a prediction of the cause of the pain to be made as early as possible in the diagnostic process before the state of pain becomes chronic. LEVEL OF EVIDENCE: Level III.

Increased focal bone tracer uptake at the popliteus muscle origin in primary TKA compared with revision TKA.

OBJECTIVE: The purpose of the study was to investigate if the TKA design (cruciate retaining (CR), posterior stabilized (PS), revision prostheses) had an influence on the bone tracer uptake (BTU) pattern at the origin of the popliteus muscle. MATERIALS AND METHODS: A total of 92 knees (male:female = 46:46) which had undergone prior TKA were included in this retrospective study, comprising the following 3 groups: (i) CR primary TKA (n = 45); (ii) PS primary TKA (n = 24); (iii) revision TKA (n = 23). All patients received a SPECT/CT after TKA surgery. SPECT/CT images were reviewed for the presence of BTU in the lateral femoral condyle (origin of the popliteus muscle) by two observers using Syngo.via software (Siemens Healthcare, Erlangen, Germany). The observers recorded the BTU pattern qualitatively in the lateral femoral condyle as either (i) absent; (ii) present and diffuse; and (iii) present and focal in the region of the popliteus muscle origin. RESULTS: In patients with a CR and PS design, focal increased BTU at the origin of the popliteus muscle was found in 80.0% and 83.3% respectively. Diffuse BTU was the predominant finding in patients with revision TKA (60.9%). The patterns of BTU did not show significant differences between the CR and the PS design. However, patterns of BTU differed significantly between primary TKA designs and revision TKA (p < 0.001). CONCLUSION: Differences in patterns of BTU at the popliteus muscle origin between primary TKA and revision prosthesis may be the result of decreased insertional tensile forces of the popliteus muscle after revision surgery due to increased stability provided by the revision design.

Bone SPECT/CT has excellent sensitivity and specificity for diagnosis of loosening and patellofemoral problems after total knee arthroplasty.

PURPOSE: The primary purpose of this retrospective study with prospectively collected data was to evaluate the clinical value of SPECT/CT, in particular its impact on clinical diagnosis and patient management, in patients with pain, stiffness, or swelling after primary total knee arthroplasty (TKA). The secondary purpose was to determine the sensitivity and the specificity of SPECT/CT for different pathologies such as loosening and patellofemoral overloading. METHODS: A retrospective analysis was carried out on 214 knees in 202 consecutive patients (mean age 69 ± 11 years) with persistent or recurrent knee pain after TKA. All patients underwent clinical examination, standardised radiographs, and 99mTc-hydroxymethane diphosphonate (HDP) SPECT/CT as part of a routine diagnostic algorithm. The diagnoses before and after SPECT/CT and final treatment were recorded. TKA component position was routinely measured on 3D-reconstructed images. Intensity and anatomical distribution of bone tracer uptake were determined. RESULTS: SPECT/CT changed the clinical diagnosis and final treatment in 139/214 (65%) knees. In 117 (54.7%) out of 214 patients, revision surgery was proposed following SPECT/CT. Early onset of pain was significantly (p = 0.011) correlated with tibiofemoral stress pattern in SPECT/CT. A total of 86 knees (40.2%) were surgically revised using semi-constrained or fully constrained TKA. In 35 patients, a secondary patellar resurfacing was performed. SPECT/CT showed the clinical diagnosis to be incorrect for suspicion of tibial component loosening in 56 patients (26.2%), femoral component loosening in 53 patients (24.8%), and patellofemoral overloading/progressive patellofemoral osteoarthritis in 26 patients (12.1%) and provided different underlying causes of persistent knee pain after TKA. Likewise, SPECT/CT identified tibial component loosening in 8 patients (3.7%), femoral component loosening in 4 patients (1.9%), and patellofemoral OA in 71 patients (33.2%) without prior clinical suspected diagnosis. The sensitivity and specificity of SPECT/CT for detection of patellofemoral OA was 96.5% and 96.2%, respectively. The sensitivity and specificity for detection of tibial component loosening was 96.0% and 100%, respectively. The sensitivity and specificity for detection of femoral component loosening was 95.0% and 100%, respectively. CONCLUSION: The diagnostic benefits of SPECT/CT in the challenging and complex cohort of patients with pain after primary TKA have been proven. The excellent sensitivity and specificity for detection of tibial or femoral component loosening and diagnosis of patellofemoral OA have been surgically confirmed. Due to the benefits in establishing the correct diagnosis, SPECT/CT should be implemented as part of the routine diagnostic algorithm for patients with pain after primary TKA. LEVEL OF EVIDENCE: II.

Distribution of bone tracer uptake in symptomatic knees after ACL reconstruction compared to asymptomatic non-operated knees: a method for better differentiating patient-specific from disease-specific bone tracer uptake in SPECT/CT.

OBJECTIVE: To evaluate the differences of bone tracer uptake (BTU) in symptomatic and asymptomatic contralateral knees in patients after reconstruction of the anterior cruciate ligament (ACL-R) and to identify typical BTU patterns and threshold values to differentiate pathological from physiological BTU. METHODS: 53 patients after unilateral ACL-R were retrospectively included in the study. The population was subdivided into a group of symptomatic operated knees and a group of contralateral asymptomatic non-operated knees. BTU was measured in SPECT/CT using a validated anatomical localization-scheme and normalized mean BTU values were calculated in both knees. Wilcoxon signed rank-test and Pearson's rank-correlation coefficient were used (p < 0.05). RESULTS: Symptomatic knees after ACL-R showed significantly more BTU than asymptomatic ones (p < 0.01).Based on the measured BTU activity in SPECT/CT in symptomatic operated and asymptomatic non-operated knees, intensity thresholds of pathological BTU were established. A BTU threshold of greater than the Median + 1 SD of the asymptomatic non-operated knee was defined as pathological. In both groups the highest mean BTU was found on the femoral, tibial and patellar articular surfaces, the lowest BTU in femoral and tibial regions far from the joint. CONCLUSIONS: The established BTU thresholds for SPECT/CT in knees after ACL-R help to differentiate disease-specific from patient-specific BTU. It could be speculated that BTU in asymptomatic knees equates to the preoperative condition of the knee joint before ACL-R. Therefore, the results of this study help to understand in-vivo loading of the knee and ultimately lead to prediction of development of osteoarthritis in an early stage.

The utility of the ankle SPECT/CT scan to predict functional and clinical outcomes in supramalleolar osteotomy patients.

Combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT) is a hybrid imaging modality that shows a combination of metabolic and structural information about the ankle, including arthritis. We hypothesize that uptake in specific locations within the ankle joint can be associated with both clinical outcomes and may help predict which patients will have a successful SMO. Eighty-five pre-operative SMO patients with varus (37), valgus (41), or neutral (7) alignment of the hindfoot were assessed using SPECT/CT. The level of activation on SPECT/CT scans was measured. Pre and Post-operative functional scores were recorded. Patients with medial gutter activation had significantly worse (p < 0.05) AOFAS alignment (AOFAS-A) scores pre-operatively. Patients with varus or valgus alignment did not have any difference in VAS pain scores, but those in valgus did have worse AOFAS-P (pain) scores. Those with cystic lesions had a worse FAOS score pre-operatively. Ten patients (12.5%) had a treatment failure. Pre or post-operative alignment did not correlate to a treatment failure. The only statistically significant (p = 0.036) poor prognostic indicator was a bipolar lesion. Pre-operative SPECT/CT evaluation of an ankle before a SMO can be used to clinically correlate patient-specific factors such as pain and function in the pre and post-operative period. We caution against performing a SMO in patients with bipolar activation on a pre-operative SPECT-CT scan. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2015-2021, 2018.

Increased bone tracer uptake in symptomatic patients with ACL graft insufficiency: a correlation of MRI and SPECT/CT findings.

PURPOSE: Magnetic resonance imaging (MRI) and single-photon emission computerised tomography/computerised tomography (SPECT/CT) are used as diagnostic tools in symptomatic patients after reconstruction of the anterior cruciate ligament (ACL). The benefit of SPECT/CT in comparison with MRI is under debate. The purpose of this study was to investigate whether and how bone tracer uptake (BTU) intensity and distribution in SPECT/CT correlate with MRI findings in symptomatic patients after ACL reconstruction. METHODS: Twenty-nine patients (male:female = 22:7, mean age ± SD 26 ± 10 years) with symptoms of pain and instability after ACL reconstruction were retrospectively investigated using prospectively acquired SPECT/CT and MRI. On MRI graft tear, graft signal intensity, bone marrow oedema, tunnel cyst formation, roof impingement, roof osteophytes, local arthrofibrosis, joint effusion and synovial thickness were analysed by two readers blinded to the BTU results. BTU was anatomically localised and volumetrically quantified. Spearman's rho test was used for correlation of BTU in SPECT/CT and MRI findings (p < 0.05). RESULTS: SPECT/CT showed increased femoral and tibial BTU in patients with MRI-confirmed graft tear, signal hyperintensity of the intraarticular graft section, joint effusion, synovial thickening, roof osteophytes and bone marrow oedema. Cyst formation in the femoral tunnel results in significantly reduced BTU in femur and tibia. No correlation of increased BTU was found for graft impingement and graft arthrofibrosis. CONCLUSIONS: Bone tracer uptake in SPECT/CT and defined MRI findings in symptomatic patients after ACL reconstruction were correlated. Both imaging modalities have a definite role in post-operative diagnostic and have established their value in those patients. This study provides a better understanding of the clinical value of SPECT/CT versus MRI in the clinical decision-making process. SPECT/CT provides a window into the in vivo loading of the joint as well as bone remodelling and graft incorporation process. In addition, ACL graft insufficiency can be detected by increased BTU. LEVEL OF EVIDENCE: Retrospective cohort study, Level III.

Good clinical results but moderate osseointegration and defect filling of a cell-free multi-layered nano-composite scaffold for treatment of osteochondral lesions of the knee.

PURPOSE: The aim of this retrospective study was to evaluate the clinical and radiological results of a nano-composite multi-layered three-dimensional biomaterial scaffold for treatment of osteochondral lesions (OCL) of the knee. It was a particular radiological interest to analyse the osseointegration, filling of the defects and the bone tracer uptake (BTU), and it was hypothesised that this scaffold, which was created to mimic the entire osteo-cartilaginous unit, is integrated within the bone 12 months postoperatively and comes along with improved patients symptoms and function. METHODS: Fourteen patients (male:female = 11:3, mean age ± SD 33.1 ± 10.7 years) treated for OCL (size 1.0-3.5 cm2) were clinically and radiologically evaluated at 1 year postoperatively. The data were prospectively collected including SPECT/CT, Tegner and Lysholm scores. BTU was anatomically localised and volumetrically quantified in SPECT/CT. Defect filling was analysed in CT. Spearman's rho and Wilcoxon test were used for correlation of BTU in SPECT/CT and clinical scores (p < 0.05). RESULTS: A significant improvement in Lysholm knee score (p < 0.001) and slight deterioration in Tegner score were found (p < 0.01). A complete filling of the defect was shown in 14%, a partial filling in 14% and only minor filling was seen in 72%. A significant correlation (p < 0.001) was found between location of osteochondral lesions and increased BTU. At the lesion sites pre- and postoperative BTU was markedly increased and did not show any decrease at 12-month follow-up. Median Tegner and mean Lysholm scores did not correlate with BTU at any time. CONCLUSIONS: Treatment of OCL in the knee joint with a nano-composite multi-layered three-dimensional biomaterial scaffold resulted in a significant clinical improvement at 1-year follow-up. However, osseointegration was still ongoing at 12-month follow-up. LEVEL OF EVIDENCE: Case series, Level IV.

Increased in vivo patellofemoral loading after total knee arthroplasty in resurfaced patellae.

PURPOSE: The primary purpose of the study was to investigate if and how patellar bone tracer uptake (BTU) distribution in SPECT/CT is influenced by patellar resurfacing and the position of femoral and tibial TKA component position. METHODS: A total of 104 knees of 103 consecutive patients who underwent primary TKA were prospectively investigated. Primary patellar resurfacing was done in 40 knees while 64 had a TKA without patellar resurfacing. All patients underwent clinical assessment using the knee society score (KSS) and standardized radiographs and Tc-99m-HDP-SPECT/CT before and 12 and 24 months after TKA. Measurements of BTU including intensity and anatomical distribution pattern in eight different patellar regions were performed. Tibial and femoral TKA component position was assessed from 3D reconstructed CT data. Patellar height, thickness and tilt were measured and the distance between the tibial tuberosity and the trochlear groove (TT-TG) was measured. Univariate analysis was performed to identify differences between the two groups (p < 0.05). RESULTS: Significantly higher BTU was found in the anterior, non-articular, areas of the patella in patients who underwent patellar resurfacing (p < 0.05). The BTU pattern was similar between the groups, as the maximal uptake in both groups was seen in the superior posterior parts and the minimal uptake was seen in the inferior anterior parts. The mean postoperative KSS was significantly higher in the unresurfaced group after 12 months (p < 0.05), but with no significant difference after 24 months. CONCLUSIONS: Based on the findings of the present study, patellar resurfacing is related to significantly higher BTU in the anterior parts of the patella and lower clinical outcomes. In light of these results, routine patellar resurfacing as part of a primary TKA might be reevaluated. SPECT/CT enables a precise localization of the BTU and might be considered as the ideal imaging modality for evaluation and investigate of patellofemoral disorders after TKA.

Coronal femoral TKA position significantly influences in vivo patellar loading in unresurfaced patellae after primary total knee arthroplasty.

PURPOSE: As patellar tracking and loading is influenced by tibial tuberosity and trochlear groove (TT-TG) distance, patellar height, thickness and tilt as well as TKA component position, it was our hypothesis that these parameters significantly correlate with patellar BTU intensity and localization in SPECT/CT. The purpose of the study was to investigate whether TKA component position as well as the height, thickness and tilt of the unresurfaced patella influences the intensity and the distribution pattern of BTU in SPECT/CT. METHODS: A total of 62 consecutive patients who underwent primary TKA without patellar resurfacing were prospectively included. Demographic data such as age, gender, side and type of primary TKA were noted. All patients underwent clinical and radiological examination in a specialized knee clinic, including standardized radiographs (anterior-posterior and lateral weight bearing, patellar skyline view) and Tc-99m-HDP-SPECT/CT before, 12 and 24 months after TKA. SPECT/CT images were analysed on 3D reconstructed images. Rotational, sagittal and coronal position of the tibial and femoral TKA components was assessed using a previously validated analysis software. Measurements of BTU including intensity and anatomical distribution pattern were also performed from 3D data. The patellar height, thickness and tilt were measured, and the distance between TT and TG was measured using axial CT images. Univariate analysis was performed to identify any correlations between BTU and TKA component position and patellar measurements (p < 0.05). RESULTS: The highest median BTU was measured in the superior posterior parts of the patella. A statistically significant correlation was found between valgus alignment of the femoral TKA and increased BTU at the lateral patellar regions (p < 0.05). External rotation of the tibial TKA correlated with increased BTU at the lateral superior joint adjacent part (p < 0.05). No correlation was found between the tibial TKA position (varus-valgus, anterior and posterior slope), TT-TG distance, patellar height and patellar BTU values. CONCLUSIONS: A significant correlation of increased patellar BTU was found with femoral valgus TKA alignment. These findings highlight the importance of femoral TKA position in coronal plane with regard to post-operative patellar tracking. Moreover, these facts might explain anterior knee pain in unhappy TKA with femoral valgus alignment. LEVEL OF EVIDENCE: Diagnostic study, Level II.

Clinical value of SPECT/CT in the painful total knee arthroplasty (TKA): a prospective study in a consecutive series of 100 TKA.

PURPOSE: Bone single photon emission computed tomography (SPECT)/CT is considered as beneficial in unhappy patients with pain, stiffness or swelling after total knee arthroplasty (TKA). The purpose of this study was to identify typical patterns of bone tracer uptake (BTU), distribution and intensity values in patients after TKA. The above findings were correlated with the type and fixation of TKA, the time from TKA and intraoperative findings at revision surgery. METHODS: A total of 100 knees of 84 consecutive patients (mean age ± SD 70 ± 11 years) after TKA with persistent knee pain were prospectively included. All patients underwent clinical examination, standardized radiographs and (99m)Tc-hydroxymethane diphosphonate (HDP) SPECT/CT as part of a routine diagnostic algorithm. The diagnosis before and after SPECT/CT and final treatment were recorded. TKA component position was determined on 3-D reconstructed images. Intensity and anatomical distribution of BTU was determined. Maximum intensity values were recorded as well as ratios in relation to the proximal midshaft of the femur. Univariate analyses (chi-square test, Pearson's correlation and t test for independent samples) were performed (p < 0.05). RESULTS: SPECT/CT changed the clinical diagnosis and final treatment in 85/100 (85 %) knees. Intraoperative findings confirmed the preoperative SPECT/CT diagnosis in 32/33 knees (97 %). TKA loosening as well as progression of patellofemoral osteoarthritis (OA) was correctly diagnosed in 100 % of knees. Typical patterns of BTU for specific pathologies were identified. Loose femoral TKA components significantly correlated with increased BTU at the lateral femoral regions (p < 0.05). Loose tibial TKA components significantly correlated with increased BTU at all tibial regions (p < 0.05) and around the tibial peg (p > 0.01). CONCLUSION: The diagnostic benefits of SPECT/CT in patients after TKA have been proven. Typical pathology-related BTU patterns were identified, which will improve reporting quality. Due to the benefits in establishing the correct diagnosis, SPECT/CT should be part of the routine diagnostic algorithm for patients with pain after TKA.

Effect of high tibial osteotomy on joint loading in symptomatic patients with varus aligned knees: a study using SPECT/CT.

PURPOSE: The purpose was to prospectively evaluate the outcome, in particular the SPECT/CT bone tracer uptake (BTU) after high tibial osteotomy (HTO) due to symptomatic varus malalignment. It was the hypothesis that the BTU after HTO decreases in the medial compartment, clinical outcome and the degree of correction correlates with BTU and asymptomatic patients after HTO reveals a significantly decreased BTU in the medial subchondral areas. METHODS: Twenty-two consecutive patients with 23 knees undergoing medial opening-wedge HTO for medial compartment overloading were assessed pre- and postoperatively (12 and/or 24 months) using Tc-99m-HDP-SPECT/CT including our 4D-SPECT/CT protocol. BTU was quantified and localized to specific biomechanically relevant joint areas. Maximum absolute and relative values (mean ± standard deviation, median and range) for each area were recorded. Pre- and postoperative mechanical alignment was measured. At 24 months after HTO, the WOMAC score was used. RESULTS: A significant decrease of BTU in the medial subchondral zones after HTO was found (preoperatively to 12 and 24 months postoperatively, p < 0.01). BTU normalized in all asymptomatic patients within 24 months. This decrease was partly seen in the lateral compartments, but significantly higher in the medial compartments (p < 0.0001). A significant increase of the BTU was noted in zones directly adjacent to the plate or within the osteotomy zone (p < 0.01). Decreased BTU was observed in osteotomy zones at 24 months postoperatively following higher uptake values at 12 months postoperatively. The average valgus correction of the tibiofemoral angle was 5.9° ± 2.8°. Less stiffness correlated significantly with a higher decrease in BTU (p < 0.05). Higher postoperative BTU significantly correlated with more pain (p < 0.05). No statistical significant associations between BTU and alignment correction were found. CONCLUSION: In patients with medial compartment, overloading due to varus malalignment HTO led to a significant decrease in BTU in the medial joint compartments. SPECT/CT BTU patterns and intensity in these patients pre- to 12 and 24 months postoperatively were seen. These correlated significantly with pain and stiffness. Hence, SPECT/CT could be used for assessment of adequate correction and healing after HTO. SPECT/CT could be further used to identify the optimal individualized correction for each patient and clinical scenario. CLINICAL EVIDENCE: Diagnostic prospective study, Level II.

Pylephlebitis of a variant mesenteric vein complicating sigmoid diverticulitis.

Pylephlebitis--suppurative thrombophlebitis of the portal and/or mesenteric veins--is a rare complication of abdominal infections, especially diverticulitis. It can lead to severe complications such as hepatic abscess, sepsis, peritonitis, bowel ischemia, etc., which increase the mortality rate. Here we present a case of suppurative thrombophlebitis of the inferior mesenteric vein, as a complication of sigmoid diverticulitis. The epidemiology, clinical and radiological features as well as treatment strategies are discussed. We also review the anatomy of the mesenteric vein given its anatomic variation in the present case and how this anatomic knowledge might influence the operative approach should surgery be necessary.

Assessment of in vivo loading history of the patellofemoral joint: a study combining patellar position, tilt, alignment and bone SPECT/CT.

PURPOSE: The current study investigates whether patella height and tilt or leg alignment influence the intensity values as well as the distribution pattern of single photon emission computerized tomography/computerized tomography (SPECT/CT) tracer uptake in the patellofemoral joint. METHODS: 99mTc-HDP-SPECT/CT and radiographs of consecutive 84 knees were prospectively obtained. Lateral radiographs were analyzed in terms of patellar height, Insall-Salvati index and modified Insall-Salvati index. Skyline views were analyzed for Laurin's lateral patellofemoral angle. On long-leg radiographs, the mechanical leg alignment was classified as varus, valgus or neutral. SPECT/CT was analyzed for each anatomical region using a previously validated SPECT/CT localization and grading algorithm. Mean, standard deviation, minimum and maximum of grading for each area of the localization scheme were recorded. Nonparametric Spearman's correlations were used to correlate patellar height, lateral patellar angle and leg alignment with the tracer uptake intensity. Chi-square statistics were used for categorical data (p < 0.05). RESULTS: A patella baja correlated significantly with higher SPECT/CT tracer uptake in all patellar and lateral femoral regions (p < 0.001). A higher lateral patellar tilt correlated significantly with higher tracer uptake in the superior lateral femoral parts and the tibial tubercle. In mechanically varus aligned knees, there was significantly higher SPECT/CT tracer uptake on the medial and in valgus knees on the lateral part of the patellofemoral joint (p < 0.05). CONCLUSIONS: As the intensity and distribution of the SPECT/CT significantly correlated with patella baja and patellar tilt, SPECT/CT might be considered as imaging modality for evaluating patients with patellofemoral disorders and for follow-up of patients after patellofemoral realignment procedures. LEVEL OF EVIDENCE: Diagnostic study, Level II.

Assessment of the loading history of patients after high tibial osteotomy using SPECT/CT--a new diagnostic tool and algorithm.

BACKGROUND: Single photon emission computerized tomography and conventional computerized tomography (SPECT/CT) tracer uptake has been shown to reflect the loading history of the tibiofemoral knee joint and correlate with the mechanical and anatomical alignment. It was our primary purpose to develop a novel standardized SPECT/CT algorithm for patients undergoing high tibial osteotomy, evaluate the inter- and intra-observer reliability (OR), and assess the clinical applicability for follow-up of patients before and after high tibial osteotomy. METHODS: The localization scheme defines 9 femoral, 8 patellar, and 13 tibial zones to accurately map the examined tracer uptake volume in each anatomical area of interest. Maximum values for each area (mean ± standard deviation, median, and range) of the localization scheme were recorded as well as normalized values for the intensity of SPECT/CT tracer uptake calculated. The inter- and intra-OR was assessed for SPECT/CT localization and tracer activity. Pre- and postoperative mechanical alignment was assessed in SPECT/CT using a custom-made specialized software. The median inter- and intra-observer differences of the measured mechanical alignment were calculated along with the inter- and intra-OR. RESULTS: The localization scheme showed near-perfect inter- and intra-OR (intra-class correlation coefficient (ICC) > 0.9) for the measurement of tracer activity and localization in all anatomical regions. For measurements of mechanical alignment, there was a strong agreement between the two observers (an inter-OR of ICC = 0.99 and an intra-OR of ICC = 0.98). CONCLUSIONS: The presented SPECT/CT algorithm is highly reliable and clinically feasible. Combined with mechanical alignment analysis, it provides the surgeon with helpful information about realignment effects of high tibial osteotomies (HTOs) and might help identify the optimal personalized degree of correction in HTO surgery.

Isolated pancreatic tuberculosis: a case report and radiological comparison with cystic pancreatic lesions.

Pancreatic tuberculosis is rare and can occur in the absence of evidence of tuberculosis elsewhere in the body. Here we review the radiological appearance of pancreatic tuberculosis and compare it with other cystic pancreatic lesions, including common lesions (pseudocysts, serous or mucinous cystadenomas, intraductal papillary mucinous neoplasm) and rare lesions such as solid pseudopapillary tumors, etc. Their typical localizations within the pancreas and their malignant potential are presented. Knowledge of these can assist radiologists and clinicians in selecting the best approach towards making the correct diagnosis.

Single photon emission computerized tomography and conventional computerized tomography (SPECT/CT) for evaluation of patients after anterior cruciate ligament reconstruction: a novel standardized algorithm combining mechanical and metabolic information.

PURPOSE: The purpose of this study was to introduce a novel standardized algorithm using SPECT/CT, which promises the potential combined assessment of the biology of the joint in particular the bone-graft-fixation complex and the 3D tunnel placement in patients after ACL reconstruction. Its clinical application and inter- and intra-observer reliability should be critically evaluated. METHODS: A novel SPECT/CT localization scheme consisting of 13 tibial, 9 femoral and 4 patellar regions on standardized axial, coronal and sagittal slices is proposed. The tracer activity on SPECT/CT was localized and recorded in 25 consecutive patients using a 3D volumetric and quantitative analysis software. The inter- and intra-observer reliability was assessed for localization and tracer activity. The tunnel position was assessed in 3D-CT using standardized frames of reference. The inter- and intra-observer reliability (OR) of the measured distances were calculated (ICC). RESULTS: The localization scheme for tracer uptake analysis was useful and easily applicable in all 25 knees. It showed very high inter-OR and intra-ORs for all regions (ICC > 0.80). Tibial and femoral tunnel position measurements showed strong agreement between the readings of the two observers; the ICCs for the position, angulation, length and entry point of the femoral tunnel were >0.88 (intra-OR) and >0.86 (inter-OR). The ICC for the position of the tibial tunnel (angulation, length and entry point) was >0.79 (intra-OR) and >0.74 (inter-OR). CONCLUSIONS: The SPECT/CT algorithm presented is highly reliable and clinically feasible. Combining the 3D-mechanical information on tunnel placement and attachment areas and the 3D metabolic data will be helpful in evaluating patients with pain after ACL reconstruction.

Combined single photon emission computerized tomography and conventional computerized tomography: Clinical value for the shoulder surgeons?

With the cases described, we strive to introduce single photon emission computerized tomography in combination with conventional computer tomography (SPECT/CT) to shoulder surgeons, illustrate the possible clinical value it may offer as new diagnostic radiologic modality, and discuss its limitations. SPECT/CT may facilitate the establishment of diagnosis, process of decision making, and further treatment for complex shoulder pathologies. Some of these advantages were highlighted in cases that are frequently seen in most shoulder clinics.

Response, survival, and long-term toxicity after therapy with the radiolabeled somatostatin analogue [90Y-DOTA]-TOC in metastasized neuroendocrine cancers.

PURPOSE: To investigate response, survival, and safety profile of the somatostatin-based radiopeptide (90)yttrium-labeled tetraazacyclododecane-tetraacetic acid modified Tyr-octreotide ([(90)Y-DOTA]-TOC) in neuroendocrine cancers. PATIENTS AND METHODS: In a clinical phase II single-center open-label trial, patients with neuroendocrine cancers were treated with repeated cycles of [(90)Y-DOTA]-TOC. Each cycle consisted of a single intravenous injection of 3.7GBq/m(2) body-surface [(90)Y-DOTA]-TOC. Additional cycles were withheld in case of tumor progression and/or permanent toxicity. RESULTS: Overall, 1,109 patients received 2,472 cycles of [(90)Y-DOTA]-TOC (median, two; range, one to 10 cycles per patient). Of the 1,109 patients, 378 (34.1%) experienced morphologic response; 172 (15.5%), biochemical response; and 329 (29.7%), clinical response. During a median follow-up of 23 months, 491 patients (44.3%) died. Longer survival was correlated with each: morphologic (hazard ratio [HR], 0.46; 95% CI, 0.38 to 0.56; median survival, 44.7 v 18.3 months; P < .001), biochemical (HR, 0.75; 95% CI, 0.59 to 0.96; 35.3 v 25.7 months; P = .023), and clinical response (HR, 0.68; 95% CI, 0.56 to 0.82; 36.8 v 23.5 months; P < .001). Overall, 142 patients (12.8%) developed grade 3 to 4 transient hematologic toxicities, and 103 patients (9.2%) experienced grade 4 to 5 permanent renal toxicity. Multivariable regression revealed that tumoral uptake in the initial imaging study was predictive for overall survival (HR, 0.45; 95% CI, 0.29 to 0.69; P < .001), whereas the initial kidney uptake was predictive for severe renal toxicity (HR, 1.59; 95% CI, 1.17 to 2.17; P = .003). CONCLUSION: This study documents the long-term outcome of [(90)Y-DOTA]-TOC treatment in a large cohort. Response to [(90)Y-DOTA]-TOC is associated with longer survival. Somatostatin receptor imaging is predictive for both survival after [(90)Y-DOTA]-TOC treatment and occurrence of renal toxicity.

A novel imaging method for osteochondral lesions of the talus--comparison of SPECT-CT with MRI.

BACKGROUND: Magnetic resonance imaging (MRI) is the current standard in noninvasive diagnostics of osteochondral lesions (OCLs) of the talus. Single-photon emission computed tomography-computed tomography (SPECT-CT) is a new technique that displays different imaging qualities. The influence of the aforementioned diagnostic information on treatment decision making in talar OCLs is not known. PURPOSE: The aim of the study was to evaluate SPECT-CT in comparison with MRI for image interpretation and decision making in OCLs of the talus. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Magnetic resonance imaging and SPECT-CT of 25 patients (average age, 32 years; range, 18-69 years) were analyzed by 3 independent orthopaedic surgeons blinded to the study. Raters had to analyze images for predefined criteria of cartilage, subchondral bone plate, and subchondral bone, including bone marrow edema on MRI and scintigraphic activity on SPECT-CT. For MRI alone, SPECT-CT alone, and their combination, the treatment decision had to be defined. RESULTS: In comparison with MRI alone, treatment decision making changed in 48% of the cases with SPECT-CT alone and 52% with SPECT-CT and MRI combined. While cartilage showed good correlation for interpretation between MRI and SPECT-CT, the subchondral bone plate and subchondral bone showed substantial differences. Poor intrarater correlation highlighted the different information provided by the 2 imaging techniques. Poor interrater correlation showed a high heterogeneity in the treatment decision making of OCLs. CONCLUSION: Compared with MRI, SPECT-CT provides additional information and influences the decision making of OCL treatment. For thorough diagnostic evaluation in OCLs, performing both MRI and SPECT-CT is recommended. Further clinical investigation is needed to see if SPECT-CT in addition to MRI results in improved treatment outcomes.