Strontium 87m scanning of the sacroiliac joints in ankylosing spondylitis

Investigative for no-carrier-added 87m,gY production by the proton-induced on 89Y

The radioisotope ⁸⁷Y is one of the candidates for the SPECT and ⁸⁷Y/^87mSr generator due to its suitable half-life and decay properties. The proton-induced on the ⁸⁹Y target can be used for the production of ⁸⁷Y. The present perusal calculated the excitation function for the both ⁸⁹Y(p,x)^87m,gY direct reaction and decay of ⁸⁷Zr via ⁸⁹Y(p,3n)⁸⁷Zr → ^87mY → ^87gY indirect reaction using the TALYS-1.8 code. To simulation the production of ^87m,gY nuclide, the target thickness was designed based on the stopping power calculation by the SRIM-2013 code. The Monte Carlo code GEANT4 was used to simulate the transport of protons through the irradiation assembly. Then, the cumulative integral yield of the ^87m,gY has been calculated directly after the decay of ⁸⁷Zr radionuclide entirely. These results were in good agreement with the theoretical and reported experimental data. Eventually, the integral yield of the ^87m,gY was calculated by the indirect method from ⁸⁷Zr decay after separation the zirconium. This work provides the basis for theoretical appraisement of the use of no-carrier-added ⁸⁷Y as radiopharmaceutical for the purpose of medical applications.

Tracking rheumatic disease through imaging

This review recounts the historical, current, and future involvement of radiology and imaging in the diagnosis, management, and follow-up of patients with various rheumatic conditions. Radiographs are the mainstay of imaging patients with rheumatic conditions, although magnetic resonance imaging and ultrasonography are routinely used for early diagnosis of disease. Computed tomography remains useful in evaluating the extent of involvement of inflammatory spondyloarthropathies that classically involve the axial skeleton and sacroiliac joints. Molecular imaging has begun to play an innovative role in evaluating patients with arthritis, aiming to identify disease earlier and provide greater specificity.

18F-fluoride PET/CT for detection of sacroiliitis in ankylosing spondylitis

PURPOSE

The aim of this study was to evaluate the performance of (18)F-fluoride-PET/CT (PET/CT) for the diagnosis of sacroiliac joint (SIJ) arthritis in patients with active ankylosing spondylitis (AS).

METHODS

Included in the study were 15 patients with AS according to the modified New York criteria (AS group) and with active disease and 13 patients with mechanical low back pain (MLBP; control group) who were investigated with whole-body (18)F-fluoride PET/CT. The ratio of the uptake in the SIJ and that in the sacrum (SIJ/S) was calculated for every joint.

RESULTS

The mean SIJ/S ratio of 30 quantified joints in the AS group was 1.66 (range 1.10-3.07) with PET/CT, and the mean SIJ/S ratio of 26 quantified joints in the MLBP group was 1.12 (range 0.71-1.52). The area under the receiver operating characteristic curve for SIJ arthritis was 0.84. With plain radiography as a the gold standard and taking an SIJ/S ratio of >1.3 as the threshold, the sensitivity, specificity and accuracy on a per patient basis were 80%, 77% and 79%, respectively. On a per SIJ basis, the greatest sensitivity (94%) was found in grade 3 sacroiliitis (n = 16).

CONCLUSION

Our results suggest that quantitative (18)F-fluoride PET/CT may play a role in the diagnosis of sacroiliitis in active AS and is an alternative to conventional bone scintigraphy in times of molybdenum shortage.

Limited Diagnostic Value of Unilateral Sacroiliitis in Scintigraphy in Assessing Axial Spondyloarthritis

Objective.

To assess the diagnostic value for axial spondyloarthritis (SpA) of unilateral sacroiliitis in scintigraphy in daily clinical practice.

Methods.

In 207 patients with chronic back pain, the diagnostic value of scintigraphy was assessed retrospectively. The diagnosis made by the rheumatologist (axial SpA vs no axial SpA) was the standard.

Results.

Sensitivities of scintigraphy for any (unilateral or bilateral), bilateral, and isolated unilateral sacroiliitis were 64.9%, 40.2%, and 24.7%, respectively. Respective specificities were 50.5%, 57.7%, and 92.8%, resulting in likelihood ratios of 1.3, 1.0, and 3.4.

Conclusion.

Scintigraphy of the sacroiliac joints is of limited value for the diagnosis of axial SpA. Unilateral compared to bilateral sacroiliitis is slightly superior, but is associated with a low sensitivity.

Evaluation of quantitative sacroiliac scintigraphy for the early detection of sacroiliitis

Quantitative sacroiliac scintigraphy (QSS) was evaluated for the detection of sacroiliac (SI) joint disease before the appearance of radiographic/changes. QSS with fractional quantitation was done in 13 age- and sex-matched controls and 28 patients with different grades of radiographic sacroiliitis. The SI index of each joint was considered separately. The mean SI index values in patients with grade I radiographic sacroiliitis (1.54) and HLA-B27 positive patients with low back pain (1.50) were significantly (P less than 0.01) higher than the mean SI index of controls (1.22); but more than 50% of their SI index values were within the 97.5% confidence limits of the control range. The mean SI index values of patients with grade II (1.38) and grade III (1.34) radiographic sacroiliitis did not differ significantly from the mean SI index of controls (P greater than 0.05). Thus a large overlap between the normal and abnormal ranges of sacroiliac ratios limits the utility of quantitative sacroiliac scintigraphy for the early diagnosis of sacroiliac joint disease.

Prospective evaluation of sacroiliac scintigraphy in chronic inflammatory back pain

To assess the usefulness in screening for sacroiliitis of a wide band profile cut which included the entire sacroiliac (SI) joint, 34 patients with chronic inflammatory back pain (IBP) underwent sacroiliac joint scintigraphy with 99mTc-methylene diphosphonate while receiving no antiinflammatory therapy. The sacroiliac joint to sacrum (SIJ/S) ratios in those with back pain differed significantly from the ratios of an age-matched control group. However, 12 of the 34 patients with inflammatory back pain had normal or equivocal sacroiliac radiographs and 4 of 12 had normal SIJ/S ratios. All 4 were HLA-B27 positive, had diminished lumbar movement, and required antiinflammatory medication; 2 had diminished chest expansion; 1 has developed iritis. We conclude that this technique is not a reliable screening procedure. Therapy with antiinflammatory drugs was associated with a significant decrease in the SIJ/S ratios in 19 of the 34 who were reimaged.

Diagnostic value of sacroiliac joint scintigraphy with 99m technetium pyrophosphate in sacroiliitis

Using a quantitative method, scintigraphy of SI joints was performed by means of 99m technetium pyrophosphate in 21 patients with definite ankylosing spondylitis, in 17 control patients, and in 26 patients 'at risk', i.e. patients with complaints of back pain of the inflammatory type where on clinical grounds there was a possibility of sacroiliitis developing but with normal x-ray findings of the SI joints. Radioisotope uptake was higher in the ankylosing spondylitis group than in the other two groups, although the difference was not statistically significant with regard to the group 'at risk'. The high variance in the three groups considerably reduces the diagnostic value of the examination. In the ankylosing spondylitis group no correlation was found between radioisotope uptake and age, duration of disease, erythrocyte sedimentation rate, or radiological stage of scaroiliitis. Since the specificity and sensitivity of scintiscanning are lower than that of clinical and radiological diagnosis of the disease, we conclude that scintigraphy is not very helpful in the early diagnosis of sacroiliitis, at least by the techniques used here.

Detection of sacro-ilitis. A comparison between profile scanning with the use of 99m Tc pertechnetate and scintigraphy with 99m Tc diphosphonate

Comparative evaluation of the sensitivity of 99mTc pertechnetate scanning and of 99mTc diphosphonate scintigraphy in detecting sacro-iliac arthritis (S.I.) was performed in 32 patients with definite S.I., 14 with probable S.I., and 6 with inactive S.I., 14 patients without any evidence of S.I. served as controls. Greater diagnostic accuracy was obtained by 99mTc pertechnetate scanning than with 99mTc diphosphonate scintigraphy in patients with active S.I. in the early stages before radiological changes had become evident and in patients 22 years old and younger. In patients with inactive S.I. a close correlation was found between clinical, radiological, and scintigraphical results with 99mTc diphosphonate scintigraphy. An index obtained by adding the uptake values measured by both methods in each subject yielded valuable information in patients with S.I. that is clinically difficult to differentiate.