Hosahalli Mohan

Thyroid cancer susceptibility polymorphisms: confirmation of loci on chromosomes 9q22 and 14q13, validation of a recessive 8q24 locus and failure to replicate a locus on 5q24

Five single nucleotide polymorphisms (SNPs) associated with thyroid cancer (TC) risk have been reported: rs2910164 (5q24); rs6983267 (8q24); rs965513 and rs1867277 (9q22); and rs944289 (14q13). Most of these associations have not been replicated in independent populations and the combined effects of the SNPs on risk have not been examined. This study genotyped the five TC SNPs in 781 patients recruited through the TCUKIN study. Genotype data from 6122 controls were obtained from the CORGI and Wellcome Trust Case-Control Consortium studies. Significant associations were detected between TC and rs965513A (p=6.35×10−34), rs1867277A (p=5.90×10−24), rs944289T (p=6.95×10−7), and rs6983267G (p=0.016). rs6983267 was most strongly associated under a recessive model (PGG vs GT + TT=0.004), in contrast to the association of this SNP with other cancer types. However, no evidence was found of an association between rs2910164 and disease under any risk model (p>0.7). The rs1867277 association remained significant (p=0.008) after accounting for genotypes at the nearby rs965513 (p=2.3×10−13) and these SNPs did not tag a single high risk haplotype. The four validated TC SNPs accounted for a relatively large proportion (∼11%) of the sibling relative risk of TC, principally owing to the large effect size of rs965513 (OR 1.74).

SPECT/CT in Imaging Foot and Ankle Pathology—The Demise of Other Coregistration Techniques

Disorders of the ankle and foot are common and given the complex anatomy and function of the foot, they present a significant clinical challenge. Imaging plays a crucial role in the management of these patients, with multiple imaging options available to the clinician. The American College of radiology has set the appropriateness criteria for the use of the available investigating modalities in the management of foot and ankle pathologies. These are broadly classified into anatomical and functional imaging modalities. Recently, single-photon emission computed tomography and/or computed tomography scanners, which can elegantly combine functional and anatomical images have been introduced, promising an exciting and important development. This review describes our clinical experience with single-photon emission computed tomography and/or computed tomography and discusses potential applications of these techniques.

Multislice SPECT/CT in benign and malignant bone disease: when the ordinary turns into the extraordinary.

Nuclear medicine has entered a new era of multimodality imaging. Dedicated multislice single-photon emission computed tomography/computed tomography (SPECT/CT) cameras are relatively new additions to the diagnostic armamentarium in nuclear medicine. The integration of SPECT and CT provides precise anatomical localization and may enable characterization of abnormalities identified on planar or SPECT imaging by providing structural information by CT. The evidence in support of SPECT/CT is rapidly amounting but still relatively limited. To date, studies have suggested improved diagnostic confidence and specificity in the diagnosis of bone pathology. The combination of functional information and anatomical localization has the potential to influence medical practice with newer imaging algorithms. This review presents the current evidence and potential indications of SPECT/CT bone imaging in the assessment of benign and malignant conditions.

The EANM practice guidelines for bone scintigraphy

PurposeThe radionuclide bone scan is the cornerstone of skeletal nuclear medicine imaging. 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 disease, as well as physiological processes.MethodsThe European Association of Nuclear Medicine (EANM) has written and approved these guidelines to promote the use of nuclear medicine procedures of high quality.ConclusionThe present guidelines offer assistance to nuclear medicine practitioners in optimizing the diagnostic procedure and interpreting bone scintigraphy. These guidelines describe the protocols that are currently accepted and used routinely, but do not include all existing procedures. They should therefore not be taken as exclusive of other nuclear medicine modalities that can be used to obtain comparable results. It is important to remember that the resources and facilities available for patient care may vary.

Cost-Effectiveness of 99mTc-Sestamibi in Predicting Response to Chemotherapy in Patients with Lung Cancer: Systematic Review and Meta-Analysis

Multidrug resistance (MDR) is a major problem in lung cancer. 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) has been demonstrated to be a noninvasive marker for the diagnosis of MDR-related P glycoprotein and MDR-associated protein expression in various solid tumors. Studies have shown that 99mTc-MIBI could play a significant role in the management of lung cancer; for example, it could be used in the selection of patients for chemotherapy or radiotherapy or in combined protocols before the start of treatment. Accurate selection of chemosensitive patients with 99mTc-MIBI would result not only in effective treatment of patients but also in significant cost savings for health care providers. There is increasing pressure on health care providers to consider costs in medical decision making, particularly in the last decade, as several economic evaluations have appeared in the medical literature. The aims of this study were to undertake a systematic review of the performance of 99mTc-MIBI imaging in the assessment of treatment resistance in lung cancer and to use the findings of the review in a decision tree analysis of the potential cost-effectiveness of 99mTc-MIBI imaging in selecting lung cancer patients for chemotherapy. Methods: This study included a systematic review of the literature and a meta-analysis together with a cost-effectiveness analysis of studies with a decision tree analysis model. Results: Analysis of the studies revealed that the overall sensitivity of 99mTc-MIBI in identifying responders to chemotherapy was 94%, the specificity was 90%, and the accuracy was 92%. The sensitivity analysis revealed an incremental cost-effectiveness ratio of greater than £30,000 (∼

SPECT/CT Identification of Post-Radioactive Iodine Treatment False-Positive Uptake in a Simple Renal Cyst

42,900) for the strategy of treating all patients to recover the small loss of life expectancy (7.5 d) associated with the use of 99mTc-MIBI to preselect patients for chemotherapy. Conclusion: 99mTc-MIBI SPECT can accurately predict which patients with lung cancer will respond to chemotherapy. The use of 99mTc-MIBI to preselect patients for chemotherapy has the potential to yield significant cost savings in the health care system without a significant loss of life expectancy for patients.

The role of 99mTc-diphosphonate bone SPECT/CT in the ankle and foot.

Post–iodine 131 (I) therapy planar imaging for papillary cell thyroid carcinoma (EThy-Ca) is the standard modality utilized for post-surgical assessment of functioning remnant thyroid tissue and metastases (1). If I uptake outside the thyroid bed is discovered, the challenge is to localize it more precisely and to distinguish aberrant uptake due to EThy-Ca metastases from uptake due to other causes. We describe a patient for whom fusion of functional with anatomical imaging provided conclusive results without the need for supplementary imaging. The patient was an 85-year-old woman who presented for follow-up of recurrent papillary thyroid carcinoma (initial staging T4 N1 M0). Eight years previously she had a twostage completion thyroidectomy with neck dissection. She relapsed 2 years later and then underwent debulking of the recurrent tumor. This was followed by radioactive iodine treatment and external radiation therapy. In the following years her serum thyroglobulin (Tg) concentrations were minimally elevated without clinical evidence of progressive disease. Subsequently, her Tg level rose to 3.7 mg=L (76 mg=L off l-thyroxine replacement) and she was admitted for therapeutic administration of 5.8 GBq I. Three days after I administration she had a I whole body scan. The planar whole body images demonstrate asymmetric uptake in the salivary glands with no uptake visualized in the region of the left parotid and submandibular glands consistent with her previous surgery and radioiodine therapy. An additional area of increased tracer uptake was noted in the right upper quadrant. This uptake was initially thought to be related to bowel (Fig. 1). This was further evaluated with single photon emission computed tomography=(multi-slice) computed tomography (SPECT=CT) (Philips Precedence 16, Royal Philips Electronics, Amsterdam, The Netherlands). The focal uptake localized to uptake in a 5.5 4.2 cm simple cyst at the upper pole of the right kidney (Figs. 2 and 3). The rise of Tg was attributed to multiple pulmonary metastases, which were identified on the CT component of the study. Physiological I uptake occurs in the salivary glands, nasopharynx, and gastrointestinal tract most commonly. Less common sites of uptake are liver, on delayed imaging, and the breasts (2–6). Metastases of EThy-Ca to the kidney are very rare (7–9), and uptake of I into renal cysts is quite uncommon (5,7,8,10). Two possible mechanisms for this have been postulated. One is that there is a communication between the renal cyst and the pelvic collection system (2,5,8). The other is that it is due to human sodium iodine symporter FIG. 1. Post I whole body planar images, anterior and posterior projections, demonstrate focal uptake projected over the right upper abdomen. The asymmetric salivary gland uptake is related to previous surgery and radioiodine therapy. The activity projected over the right upper arm was skin contamination.

Comparison of 10 versus 20 min SPECT 99mTc-MDP bone scans: use of 3D-OSEM image reconstruction with distance-dependent resolution modelling.

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.

Incidence and Significance of Incidental Focal Thyroid Uptake on (18)F-FDG PET Study in a Large Patient Cohort: Retrospective Single-Centre Experience in the United Kingdom.

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 A: mean DRM10 s=4.3±0.5, mean FBP20 s=3.8±0.8, P=0.0064; observer B: mean 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.

Beware of the focal uptake at the ischium on the bone scan in prostate cancer.

Objective: To assess the prevalence and pathological nature of incidental focal thyroid uptake on 18F-FDG (2-[18F]-fluoro-2-deoxy-D-glucose) PET (positron emission tomography) and examine the role of the maximum standardised uptake value (SUVmax) to differentiate benign from malignant thyroid pathology. Material and Methods:18F-FDG PET reports were retrospectively reviewed. Incidental focal tracer uptake in the thyroid was noted in 147 patients (0.5%). Patients with known primary thyroid malignancy were excluded. The final diagnosis was made following ultrasonography of the neck, fine-needle aspiration cytology (FNAC) or histopathology of the surgically resected specimen where surgery was indicated. A Mann-Whitney U test was used to compare the SUVmax of benign and malignant thyroid pathology. Receiver operating characteristic (ROC) analysis was performed to identify an SUVmax cutoff in differentiating benign from malignant pathology. Results: A final diagnosis was achieved in 47/147 (32%) of the patients. The diagnoses included benign lesions in 36 patients and malignancy in 9 patients. In 2 patients, FNAC demonstrated indeterminate follicular lesions; however, surgical excision was not performed. There was a highly significant difference in the mean SUVmax of malignant focal thyroid uptake (15.7 ± 5.9) compared to that of benign lesions (7.1 ± 6.8) with a p value of 0.000123. An SUVmax of 9.1 achieved a sensitivity of 81.6%, specificity of 100% and area under the curve of 0.915 in the ROC analysis differentiating benign from malignant disease. Conclusion: The malignancy potential of incidental focal thyroid uptake remains high and warrants prompt and appropriate follow-up by the clinician. The SUVmax may aid in further characterisation of the lesion and its management.