The evaluation of the osseous ankle and foot pathology often poses a clinical and diagnostic challenge because of the complex anatomy and structural biomechanics of the region. Further investigation ...involves a multimodality imaging approach. Although both structural and functional imaging techniques have their strengths, namely, the high specificity of the former and superior sensitivity of the latter, they also have a number of limitations when used in isolation. These include the inability to determine the functional significance of pathological anatomical abnormalities or to further characterize or localize abnormal metabolic activity. The development of integrated single-photon emission computed tomography/computed tomography systems has aimed to overcome the limitations of separate anatomical and functional imaging techniques. This may be of particular value in ankle and foot assessments, in which multiple joints may be affected by different pathologies. This review article aims to highlight the role of both structural and functional imaging techniques, with particular emphasis on the incremental value of single-photon emission computed tomography/computed tomography in evaluation of this complex anatomical region.
Clubbing of the fingers has a myriad of causes. It is a well-recognized paraneoplastic phenomenon in nonsmall cell carcinoma of the lung. The pathogenesis is still not fully understood, but it is ...associated with increased vascularity in the nail beds. The authors present a Tc-99 MDP bone scintigram illustrating clubbing in the hand, a primary lung tumor, as well as the underlying bony abnormality. The case emphasizes the importance of vigorously exploring the nonskeletal components of bone scintigraphy.
P-glycoprotein (P-gp) and Multidrug Resistance Protein (MRP1) are the key cellular drug efflux transporters in a range of tissues and the radiopharmaceutical 99mTc-sestamibi has been demonstrated to ...be a substrate for both transporters in a number of in vivo and in vitro studies. The elimination rate of 99mTc-sestamibi from the lungs following inhalation as an aerosol has been shown to be delayed in healthy smokers versus non-smokers. It was hypothesized that this was the result of smoke-induced up-regulation of P-gp. The aims of this study were: To examine the relationship between the lung elimination rate of inhaled sestamibi and immuno-histochemical expression of broncho-pulmonary MRP1 and P-gp. To study the repeatability of the technique and assess the effect of various demographic factors affecting the clearance of inhaled sestamibi. Methods: Thirty-five participants were included in the study. They all underwent an inhaled 99mTc-sestamibi clearance study. Of these, 13 were patients undergoing surgery for primary lung cancer (5/13) or spontaneous pneumothorax (8/13). There were 22 healthy volunteers. All participants gave informed consent prior to the study. Semi-quantitative assessment (grade 0-3) of MRP1 and P-gp expression in lung on immuno-histochemical examination was correlated with the elimination rate of sestamibi from the lung tissue. The effect of various factors on inhaled sestamibi clearance including smoking status, age, gender and locality of residence was evaluated. The study was repeated in 10 participants to assess the repeatability and inter-observer reproducibility of the technique. Results: MRP1 expression was seen in 12/13 patients while P-gp in only 2/13. The mean sestamibi elimination rate was faster in patients expressing low levels of MRP1 expression (grade 0-1), mean T½ of 105 ± 20 min, compared with those with higher levels of MRP1 expression (grade 2-3), mean T½ of 149 ± 28 min (P = 0.008). Inhaled sestamibi clearance was significantly delayed in smokers (n=17), mean T½ = 142 ± 29 min, compared to non smokers (n=18), mean T½ = 91 ± 14 min (P < 0.0001). The clearance of inhaled sestamibi was also significantly delayed in non smoking older patients >30 y (n= 6), mean T½ = 101 ± 15 min, compared to younger patients <30 y (n=12), mean T½ = 86 ± 11 min (P < 0.05), and in non smoking men (n=7), T½ = 130 ± 37 min, compared to women (n=11), T½ = 105 ± 28 min (P < 0.05). There was however no significant difference noted between urban dwellers from London (n=22), mean T½ = 89 ± 11 min, compared to semi-rural dwellers (n=13), mean T½ = 96 ± 20 min (P > 0.05). Bland-Altman analysis revealed excellent agreement between test and re-test values with a (bias) of 4.8 min and a standard deviation of the difference (precision) of 5.7 min. There was an excellent inter-observer reproducibility seen with a Spearman Rho value of 0.96 and p<0.05 Conclusion: The study results indicate a significant correlation between the predominant transporter in lung (broncho-alveolar epithelium) MRP1 and inhaled 99mTc- Sestamibi clearance. Inhaled 99mTc- Sestamibi clearance is a safe and reproducible technique. Smoking, increasing age and male gender appear to significantly prolong the lung clearance of inhaled sestamibi. There was however no definite effect of environmental status on the clearance rate observed.
P-glycoprotein (P-gp) and Multidrug Resistance Protein (MRP1) are the key cellular drug efflux transporters in a range of tissues and the radiopharmaceutical 99mTc-sestamibi has been demonstrated to ...be a substrate for both transporters in a number of in vivo and in vitro studies. The elimination rate of 99mTc-sestamibi from the lungs following inhalation as an aerosol has been shown to be delayed in healthy smokers versus non-smokers. It was hypothesized that this was the result of smoke-induced up-regulation of P-gp. The aims of this study were: To examine the relationship between the lung elimination rate of inhaled sestamibi and immuno-histochemical expression of broncho-pulmonary MRP1 and P-gp. To study the repeatability of the technique and assess the effect of various demographic factors affecting the clearance of inhaled sestamibi. Methods: Thirty-five participants were included in the study. They all underwent an inhaled 99mTc-sestamibi clearance study. Of these, 13 were patients undergoing surgery for primary lung cancer (5/13) or spontaneous pneumothorax (8/13). There were 22 healthy volunteers. All participants gave informed consent prior to the study. Semi-quantitative assessment (grade 0-3) of MRP1 and P-gp expression in lung on immuno-histochemical examination was correlated with the elimination rate of sestamibi from the lung tissue. The effect of various factors on inhaled sestamibi clearance including smoking status, age, gender and locality of residence was evaluated. The study was repeated in 10 participants to assess the repeatability and inter-observer reproducibility of the technique. Results: MRP1 expression was seen in 12/13 patients while P-gp in only 2/13. The mean sestamibi elimination rate was faster in patients expressing low levels of MRP1 expression (grade 0-1), mean T½ of 105 ± 20 min, compared with those with higher levels of MRP1 expression (grade 2-3), mean T½ of 149 ± 28 min (P = 0.008). Inhaled sestamibi clearance was significantly delayed in smokers (n=17), mean T½ = 142 ± 29 min, compared to non smokers (n=18), mean T½ = 91 ± 14 min (P < 0.0001). The clearance of inhaled sestamibi was also significantly delayed in non smoking older patients >30 y (n= 6), mean T½ = 101 ± 15 min, compared to younger patients <30 y (n=12), mean T½ = 86 ± 11 min (P < 0.05), and in non smoking men (n=7), T½ = 130 ± 37 min, compared to women (n=11), T½ = 105 ± 28 min (P < 0.05). There was however no significant difference noted between urban dwellers from London (n=22), mean T½ = 89 ± 11 min, compared to semi-rural dwellers (n=13), mean T½ = 96 ± 20 min (P > 0.05). Bland-Altman analysis revealed excellent agreement between test and re-test values with a (bias) of 4.8 min and a standard deviation of the difference (precision) of 5.7 min. There was an excellent inter-observer reproducibility seen with a Spearman Rho value of 0.96 and p<0.05 Conclusion: The study results indicate a significant correlation between the predominant transporter in lung (broncho-alveolar epithelium) MRP1 and inhaled 99mTc- Sestamibi clearance. Inhaled 99mTc- Sestamibi clearance is a safe and reproducible technique. Smoking, increasing age and male gender appear to significantly prolong the lung clearance of inhaled sestamibi. There was however no definite effect of environmental status on the clearance rate observed.
RATIONALEThe isotope bone scan is routinely used in the management of prostate cancer as the skeleton is the second most common area of metastasis after lymph nodes. A classic site of involvement in ...the pelvis is the ischium, and the aim of this study was to assess the value of single-photon emission computed tomography/computed tomography (SPECT/CT) imaging in patients with focal ischial uptake on the planar scan.
MATERIALS AND METHODSThis was a retrospective study of consecutive 150 patients with prostate cancer who were referred for a whole-body bone scan between August 2007 and 2008. Two experienced nuclear medicine consultants along with a musculoskeletal radiologist reviewed the scans.
RESULTSSixty-eight patients were diagnosed with widespread metastases and 46 patients showed typical degenerative disease changes on planar whole-body imaging. SPECT/CT imaging was done in 36 patients to clarify the diagnosis in areas of indeterminate uptake noted on planar whole-body imaging. Ten of these 36 patients who had focal increased ischial uptake were included in the study. Only three of these 10 patients were diagnosed as having a metastatic lesion with the presence of an enthesopathy, a common finding.
CONCLUSIONIsolated focal uptake in the ischium is a relatively common finding in patients with prostate cancer and there is concern that this, on occasion, could be misinterpreted as metastasis. SPECT/CT imaging has an important role in differentiating a benign from a malignant lesion.
BACKGROUNDIterative reconstruction with system response modelling has been implemented in commercial software by manufacturers for distance-dependent resolution modelling (DRM) of the collimator ...physical effects. Initial experience with such algorithms also shows improvements in noise characteristics with lower dependency on counting statistics. In this study the performance of one such algorithm, the Philips Astonish, was assessed for bone single-photon emission computed tomography (SPECT) acquired at count levels reduced by half on technetium-99m methylene diphosphonate scans.
METHODSFor every SPECT scan, two sets of images were generated with the aid of concurrent data acquisition(i) a conventional scan used routinely for reporting at 20 s per projection reconstructed with filtered back-projection (FBP20 s) and (ii) a scan at 10 s per projection reconstructed with Astonish (DRM10 s). Phantom and pilot patient data were used to initially establish optimal reconstruction parameters. Subsequently, patient studies (n=28) were scored independently by two experienced observers (blinded to reconstruction method or acquisition time) for image quality based on a scale of 1–5. Observers were also asked to report the number of observed lesions in each scan.
RESULTSResults show that scores were better or equivalent for the vast majority of DRM10 s images compared with FBP20 s with statistically significant differences between the two methods (observer Amean DRM10 s=4.3±0.5, mean FBP20 s=3.8±0.8, P=0.0064; observer Bmean DRM10 s=3.6±0.8, mean FBP20 s=3.1±0.9, P=0.0073). Improvements in image quality for DRM10 s were reported on 16 out of 28 scans for observer A and 15 out of 28 scans for observer B, whereas 8 out of 28 and 9 out of 28 scans received equivalent scores, respectively. The total number of lesions reported for both DRM10 s and FBP20 s was 72 for both observers showing no differences between the two methods.
CONCLUSIONThese results indicate that the use of the DRM algorithm has the potential for reducing bone SPECT acquisition times by half without compromising current levels of image quality and diagnostic value, or reduce the injected dose when radioactivity supply is limited.
A 21-year-old man presented with a 3-year history of right heel pain. There was no history of trauma. Clinically, Achilles tendonitis was suspected.Plain radiography demonstrated a right plantar ...calcaneal spur. Bone scintigraphy (planar imaging and SPECT/CT) revealed changes in keeping with a right-sided plantar fasciitis, with an enthesopathy at the site of the Achilles tendon insertion and an associated bursitis.The modalities most commonly used to investigate heel pain are ultrasound and MRI. However, this case highlights the utility of hybrid SPECT/CT imaging in the anatomic localization of increased metabolic activity.
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