Quantitative sacroiliac joint scintigraphy in normal subjects and patients with sacroiliitis

Correlation Between Diagnostic Imaging Findings of Sacroiliitis and Inflammation Parameters

Objectives Sacroiliitis is an inflammation of the sacroiliac joints. Diagnostic imaging has a very important role in the diagnosis of sacroiliac involvement in the disease process. In addition, laboratory parameters can also be useful for the detection of inflammation. This study aims to investigate the relationship between active sacroiliitis and subclinical inflammation parameters in patients who underwent MRI and 99mTc-methylene diphosphonate (MDP) bone scintigraphy.

Material and Methods This study includes 65 patients with suspected spondyloarthritis (SpA). Patients who had a sacroiliac MRI, a 99mTc-MDP bone scintigraphy and a complete blood count (CBC) within 3 months were reviewed retrospectively. Sacroiliac joints were evaluated bilaterally by using bone scintigraphy and MRI. Blood inflammation parameters were further assessed regarding evidence of probable sacroiliitis.

Results Significant differences were reported between MRI groups for sacroiliac indices (SII) (p=0.003), neutrophil-to-lymphocyte ratio (NLR) (p=0.008), C-reactive protein (CRP) (p = 0.037), and white blood cell (WBC) count (p=0.031). A significant correlation was found between active sacroiliitis and SII (p=0.001), CRP (p=0.000), erythrocyte sedimentation rate (ESR) (p=0.000), and NLR (p=0.001). Based on the ROC curve analysis, SII was found to have a sensitivity of 64.3% and specificity of 69.8%; NLR was found to have a sensitivity of 64.3% and specificity of 73.3% for diagnosing active sacroiliitis.

Conclusions Subclinical inflammation indices obtained from CBC and, particularly, NLR may contribute to disease activity assessment like acute-phase reactants. However, this needs to be confirmed in further studies.

Quantitative scintigraphy in discriminating sacroiliac joint physiological and pathological uptake

Background

Bone scintigraphy is a highly sensitive diagnostic nuclear medicine imaging technique that uses a radiotracer to evaluate the distribution of active bone formation in the skeleton related to malignant and benign diseases, as well as physiological processes. Subjective increase of the radioactivity at the sacroiliac joint in cancer patients could indicate physiological, metastatic, or inflammatory (sacroiliitis) cause. In this single-center study, we aimed to settle the normal sacroiliac index (SII) in males and females and if it differs from side to other, as a more accurate quantitative method than qualitative one, and assess its validity in discriminating the cause in pathological increase.

Results

Sacroiliac index can differentiate physiological uptake at the SIJ from pathological uptake with a highly significant value (P < 0.001). Using SII at a cutoff value 1.17 had 100% sensitivity and specificity in differentiating between the two conditions. The normal SII in our institute ranged from 0.9 to 1.14 with no significant difference between right and left SIJs. The mean SII was 1.33 ± 0.11 in patients with ankylosing spondylitis (AS) and 1.38 ± 0.1 in metastatic cases with no significant difference in SII between the two diseased groups (P = 0.49).

Conclusion

Bone scintigraphy is widely used in our institute and qualitative assessment of SIJ uptake is sometimes confusing. In this study, we assessed the normal SII range in physiological uptake and assessed a cutoff value (which is lower than other races) above which any increase in SIJ uptake is considered pathological. We could not confirm a cutoff value to discriminate between AS and metastatic affection of SIJ.

Sacroiliac indicis increase the specificity of bone scintigraphy in the diagnosis of sacroiliitis

Objective: Bone scintigraphy is a highly sensitive method in the evaluation of sacroiliitis. Aim of this study is firstly to evaluate interobserver variation of partial and whole sacroiliac indicis, secondly investigation of clinical importance of these indicis in the diagnosis of sacroiliitis.

Methods: Fourty-six subjects (24 female: 35.4±11.9; 22 male: 43.1±12.4) without sacroiliitis 45 subjects with low back pain (33 female: 43.3±11.5, 11 male: 35.5±17.2) were included in the study. For right (R) and left (L) whole indices (WSI) irregular region of interest (ROI), for partial indices superior (S) and inferior (I) rectangular ROI were used. For background activity, rectangular ROI was drawn from the sacral region. Indices were calculated from ratio of average counts of sacroiliac and background regions. Two independent observers calculated sacroiliac indices. Interobserver agreement was evaluated by Pearson analysis.

Results: There was no significant interobserver difference (p>0.05). Significant correlation existed between all calculated indices. Among 45 patients with suspicion of sacroiliitis 15 had final diagnosis of sacroiliitis and all of the Tc-99m methilenediphosphonate planar and SPECT bone scintigraphy results of these patients were concordant with sacroiliitis. There were 8 false positive results in other 30 patients. Seven of these eight patients had normal index values. If the scintigraphy would be evaluated in conjuction with indicis the specificity would increase from 73% to 97% but sensitivity decreases from 100% to 80%. There was significant correlation between the observers calculated indicis (p<0.001).

Conclusion: Superior and inferior sacroiliac index values can be used with confidence. If we use sacroiliac index values to confirm positive results; index values can increase the specificity of bone scintigraphy.

The usefulness of bone SPECT/CT imaging with volume of interest analysis in early axial spondyloarthritis

Background

The role of conventional bone scintigraphy in diagnosing early axial spondyloarthritis (SpA) is yet controversial. Single positron emission computed tomography (SPECT) plus CT is an imaging modality that adds better anatomical information to scintigraphy of the sacroiliac (SI) joint. Our aim was to investigate the usefulness of bone SPECT/CT with volume of interest (VOI) analysis in early axial SpA patients.

Methods

Twenty patients (male: female ratio = 12:8; age range = 17–65 years) presenting with inflammatory back pain meeting the Amor criteria of early axial SpA were recruited from a single center in South Korea. Bone scintigraphy was performed 180 min after intravenous injection of 1110 MBq of Tc-99 m-HDP, followed by bone SPECT/CT. The ratio between the entire SI joint and sacrum (SIS ratio) was measured by both bone SPECT/CT and bone scintigraphy. Data from 13 controls were also evaluated. Receiver operating characteristic (ROC) curve was plotted for further analysis, and the correlation between the SIS ratio and SI joint grade by plain radiography was assessed.

Results

The SIS ratio of early axial SpA patients vs. control subjects was significantly increased in bone SPECT/CT (p < 0.001). However, no significant difference was detected in bone scintigraphy. ROC curve analysis showed a significant difference in the area under curve (AUC) of bone SPECT/CT vs. bone scintigraphy (0.862 vs. 0.523, respectively; p < 0.001). With a cut-off SIS ratio of 1.50, ROC curve analysis showed a sensitivity of 80.0% and specificity of 84.6% in bone SPECT/CT. The SIS ratio measured in SPECT/CT, but not that measured in bone scintigraphy, was significantly increased with a higher grade of SI joint changes in plain radiography (p = 0.014).

Conclusion

Bone SPECT/CT is more useful than conventional bone scintigraphy in identifying sacroiliitis in early axial SpA patients, even with mild SI joint changes in plain radiography. By combining CT, we can accurately delineate the sacrum and SI joint uptake with our VOI method.

Early spondyloarthropathy: scintigraphic, biological, and clinical findings in MRI-positive patients

There are no specific diagnostic tests or a gold standard method for measuring disease activity and outcome in spondyloarthropathies (SpA). Many different methods have been developed to assess the signs and symptoms in SpA. The aim of this study was to evaluate the value of scintigraphy, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and Bath Ankilosing Spondylitis Disease Activity Index (BASDAI) in the evaluation of disease activity in early axial SpA diagnosed with magnetic resonance imaging (MRI). Thirty early MRI-positive axial SpA patients (23 males, 7 females) with a median age of 35 (18-55) years and a median duration of inflammatory low back pain of 24 (8-60) months were included in the study. In the patients with sacroiliitis, the sensitivity, specificity, and positive and negative predictive values of disease activity parameters were determined regarding MRI as the gold standard method. The sensitivities of quantitative scintigraphy, visual scintigraphy, ESR, CRP, and BASDAI were 32, 82, 35, 71, and 60%, respectively. The specificities of quantitative scintigraphy, ESR, CRP, and BASDAI were 100, 100, 50, and 100%, respectively. The positive predictive values of quantitative scintigraphy, visual scintigraphy, ESR, CRP, and BASDAI were 100, 92, 100, 95, and 100%, respectively. The negative predictive values of quantitative scintigraphy, ESR, CRP, and BASDAI were 9, 10, 11, and 15%, respectively. Regarding MRI as the gold standard in the evaluation of disease activity, combined visual and quantitative bone scintigraphy can be valuable in patients with MRI-incompatible implants. Additionally, use of cheaper, simple, and readily reproducible tests such as CRP and BASDAI together could be valuable and practical in detecting disease activity in long-term follow-up of these patients.

Age, body mass index, and gender differences in sacroiliac joint pathology

OBJECTIVE

To evaluate the correlation between age, gender, and body mass index as they relate to sacroiliac joint pathology diagnosed by dual comparative local anesthetic blocks.

DESIGN

This was a retrospective review of patients at a university spine center from August 2001 until August 2004.

RESULTS

One hundred fifty-eight patients underwent sacroiliac joint (SIJ) injections with average symptom duration of 34.0 mos. Of those patients, 26.6% were found to have SIJ pain by dual injections. The average age of this group was 53.3 yrs old; for those who had negative injections, it was 46.8 yrs old (P = 0.0025). The body mass indexes for the positive and negative SIJ pain groups were 30.2 and 29.3 kg/m2 (P = 0.40), respectively. The gender makeup of the positive and negative groups showed 64.3% female and 62.1% female (P = 0.85), respectively. Smoking tobacco status was not statistically significant between the two groups, with 29.6% of smokers having a positive block and 26.1% having a negative block (P = 0.35).

CONCLUSIONS

Our results suggest an age difference for those patients who have SIJ pain. These patients tend to be older than those without. Gender, age, and smoking status were not found to correlate with SIJ pathology.

The usefulness of Tc-99m-MDP bone scintigraphy in detection of articular involvement of Behçet's disease

Articular involvement was reported to be present in approximately 5-76% of Behçet patients. Therefore, we need a useful non-invasive method to detect articular involvement early in Behçet patients with nonspecific complaints. We aimed to evaluate the usefulness of 99mTc-methylene diphosphonate (Tc-99m-MDP) bone scintigraphy in the detection of the articular involvement of Behçet's disease (BD). Bone scintigraphy with Tc-99m-MDP was performed in 32 (17 male, 15 female) consecutive patients with BD. The sacroiliac (SI) joints with SI index higher than 1.34 were diagnosed as having sacroiliitis. Although joint complaints were present in only 8 (25%) patients, we detected joint involvement by scintigraphy in 27/32 (84.4%) Behçet patients mostly affecting the knees (62.5%), ankles (59.4%), SI joints (25%), wrists (21.9%), shoulders (18.7%), elbows (12.5%) and hips (3.1%). The articular involvement was monoarticular in four cases (12.5%) and was oligoarticular in the remaining. There was no correlation between joint involvement and age, gender, disease duration, drug usage or other clinical manifestations. Despite the fact that our patients were clinically asymptomatic and had normal pelvis radiography, sacroiliitis was found in 8 patients (25%). Bone scintigraphy is sensitive in the diagnosis of joint involvement allowing earlier diagnosis and showing the presence of articular involvement, especially in SI joints.

Tc-99m polyclonal human immunoglobulin scintigraphy in brucellosis

The aim of this study was to evaluate the accuracy of Tc-99m polyclonal human immunoglobulin (HIG) scintigraphy for the diagnosis of brucellosis, and to compare its effectiveness in the diagnosis of osteoarticular involvement in comparison with bone scanning. Of 30 patients with brucellosis, Tc-99m HIG detected osteoarticular involvement in 18 (60%) patients, in whom the sacroiliac joints were affected most commonly (n = 13; 72.2%), with statistically predominant bilateral involvement (p < 0.05). By bone scanning, the rate of osteoarticular involvement was 70% (21 of 30 patients), and the joints affected most commonly were sacroiliac (15 of 21 patients; 71.4%). Although bilateral involvement was observed mostly by bone scanning, there was no significant difference between the rate of bilateral and unilateral involvement. The anatomical distribution of osteoarticular complications, as detected by Tc-99m HIG and bone scintigraphy, did not differ significantly. With Tc-99m HIG, orchitis was detected in two patients and paravertebral abscess in one patient. Since bone scanning did not detect these soft tissue complications, Tc-99m HIG scintigraphy might be useful for the detection of both osteoarticular and soft tissue complications resulting from brucellosis.

Young athletes with low back pain: skeletal scintigraphy of conditions other than pars interarticularis stress

PURPOSE

Skeletal scintigraphy is an important method for showing evidence of stress injuries affecting the partes interarticulares of young athletes with low back pain. Other etiologies of low back pain may also cause uptake abnormalities in these patients. How often do the results of skeletal scintigraphy support diagnoses other than stress injuries to the partes interarticulares and what are these diagnoses?

MATERIALS AND METHODS

We retrospectively reviewed the records of 209 young patients (149 females, 60 males; age range: 8-21 years, mean: 15.7 years) with low back pain and no previously treated vertebral condition who were consecutively referred from a sports medicine clinic to skeletal scintigraphy.

RESULTS

Sites of high uptake supportive of diagnoses other than pars interarticularis stress were shown in 36 (17%) of the 209 patients. Other diagnoses supported by skeletal scintigraphy included stress at the articulation between a transitional vertebra and the sacrum, injuries to the vertebral body ring apophysis, sacral fracture, spinous process injury, and sacroiliac joint stress.

CONCLUSION

Skeletal scintigraphy shows uptake abnormalities supportive of diagnoses other than pars interarticularis stress in a significant number of young patients with low back pain. The uptake abnormalities shown are usually stress-related in this select population.

The investigation of sacroiliitis with different imaging techniques in spondyloarthropathies

PURPOSE

The aim of this study was to compare the value of different imaging techniques in spondyloarthropathy (SpA) patients with inflammatory low back pain.

PATIENTS AND METHODS

We evaluated 54 patients who fulfilled the European spondyloarthropathy classification criteria and had inflammatory low back pain. They were subdivided into two groups according to changes on plain radiography rated on a 0-4 scale according to modified New York criteria. Group A patients had at least grade-2 unilateral or bilateral changes in the sacroiliac (SI) joints, whereas group B included patients with radiologic changes not exceeding grade 0-1. Quantitative SI scintigraphy and magnetic resonance imaging (MRI) were performed to investigate the value of these techniques to the diagnosis of sacroiliitis, and the sacroiliac joint:sacrum uptake ratios were calculated. Scintiscanning was done in 80 healthy subjects to define the normal range.

RESULTS

The sensitivities of plain radiography, quantitative SI scintigraphy, and MRI were 61%, 55%, and 89%, respectively, among the patients with SpA. MRI and quantitative SI scintigraphy detected sacroiliitis in 97% and 49% of group A, respectively. In group B, these results were 76% and 66%, respectively.

CONCLUSION

Magnetic resonance imaging is the most sensitive method for detecting acute or chronic changes in SpA patients with histories of inflammatory low back pain and normal or indeterminate findings on plain radiographs.

The sacroiliac joints: evaluation using nuclear scintigraphy. Part 2: Lame horses

REASONS FOR PERFORMING STUDY

Sacroiliac (SI) joint disease is difficult to diagnose definitively on clinical grounds.

HYPOTHESES

Lameness not attributable to SI joint pain may result in asymmetrical uptake of radiopharmaceutical in the tubera sacrale and SI joints; and that horses with clinical signs suggestive of sacroiliac joint disease would have differences in the ratios of radiopharmaceutical uptake between the fifth lumbar vertebra (L5) and either the tubera sacrale or SI joints compared with normal horses.

OBJECTIVES

To determine whether differences in radiopharmaceutical activity could identify individuals with presumed SI joint region pain.

METHODS

The scintigraphic appearance of the pelvic region of 234 horses (Group I) with lameness unrelated to the SI joints was compared with that for 40 normal horses (Group N) in full work and that for 41 horses with suspected SI joint disease (Group II). The effect of age, sex, lame limb and discipline were assessed in Group I. Motion-corrected scintigraphic images were assessed grossly, using profile analysis and by comparing ratios of uptake of mean count per pixel between L5 and each of the left (L) tuber sacrale (TS), right (R) TS, LSI and RSI joints. Left-right symmetry was compared.

RESULTS

Lame horses (Group I) had greater asymmetry of radiopharmaceutical uptake in the tubera sacrale compared with normal horses. Horses with right hindlimb lameness had a larger RSI/LSI ratio compared to normal horses. In Group I L5/LTS, L5/RTS and L5/RSI increased with age, and there was a trend for L5/LSI to increase with age. In horses with presumed sacroiliac joint disease (Group II), L5/LTS, L5/RTS and L5/RSI were all greater compared with normal horses. Detection of marked left-right asymmetry by quantitative analysis or profile analysis was helpful in discriminating between those horses with clinical signs compatible with SI joint disease and either normal horses or those lame due to another cause.

CONCLUSIONS AND POTENTIAL RELEVANCE

Scintigraphic evaluation of the SI region is useful to identify SI joint disease in combination with other clinical signs supportive of the diagnosis. However, diagnosis should not be based on this alone because of some degree of overlap in the range of radiopharmaceutical uptake between horses with SI joint disease and both normal horses and those with other causes of lameness.

The evaluation of sacroiliitis using 99mTc-nanocolloid and 99mTc-MDP scintigraphy

The role of imaging studies in the evaluation of patients with sacroiliitis is controversial. We aimed to evaluate the role of nanocolloid and bone scintigraphy in patients with sacroiliitis and to investigate the clinical relevance of imaging findings. Thirty-two patients with clinically sacroiliac disease (nine females, 23 males, aged 22-47 years) underwent scintigraphic and radiographic examinations and all imaging studies were performed within 2 weeks. Twenty-five subjects were also included as a control group (10 females, 15 males, aged 20-51 years) for quantitative analysis of the bone scan. The quantitative analysis was done by using regions of interest drawn over the right and left sacroiliac (SI) joint and sacrum (S) and SI/S ratios were calculated. Abnormal uptake was defined as an uptake higher than the mean +/- 2 SD of the control SI/S values. Bone scintigraphy was performed using a three-phase technique and single photon emission computed tomography (SPECT). Nanocolloid scintigraphy (NS) was performed 1 h later, after administration of 370 MBq 99mTc-nanocolloid, and evaluated visually. Each of the scintigraphic examinations was performed on separate days within the same week. Sensitivity values were 25%, 47%, 69% and 97%, and specificity values were 80%, 90%, 95% and 90% in quantitative bone scanning (QBS), 99mTc-NS, planar and SPECT bone imaging, respectively, when the clinical findings were considered as the 'gold standard'. Our results showed that bone SPECT scanning was more sensitive than planar imaging, but planar imaging was the most specific method. SPECT was also the most associated technique with clinical findings. 99mTc-NS was neither specific nor sensitive enough in the detection of sacroiliitis although it could be helpful for the confirmation of inflammation.