Charoonsak Somboonporn

Diagnostic accuracy of planar, SPECT, and SPECT/CT parathyroid scintigraphy protocols in patients with hyperparathyroidism

BACKGROUND Several parathyroid scintigraphy protocols have been used for preoperative localization of hyperfunctioning parathyroid glands in patients with hyperparathyroidism. The aim of this study is to compare the diagnostic accuracy of various parathyroid scintigraphy protocols. MATERIAL AND METHODS A retrospective diagnostic accuracy study with histopathology as the reference standard was done. Five imaging protocols were investigated including planar dual tracer Tc-99m pertechnetate/Tc-99m sestamibi (DT), planar dual phase Tc-99m sestamibi (DP), and combined dual tracer dual phase (DTDP) protocols, as well as add-on single photon emission computed tomography (SPECT), and single photon emission computed tomography/computed tomography (SPECT/CT). RESULTS A total of 63 patients underwent parathyroid scintigraphy and subsequent parathyroid surgery with a total of 106 excised lesions with histopathological diagnosis. On a lesion-based analysis, sensitivity and specificity (with 95% confidence interval) of protocols were as follows. DT protocol: 69.4% (53.1-82.0%) and 80.0% (49.0-94.3%); DP protocol: 78.6% (52.4-92.4%) and 33.3% (9.7-70.0%); DTDP protocol: 64.7% (47.9-78.5%) and 50.0% (18.8-81.2%); SPECT: 92.3% (66.7-98.6%) and 75.0% (30.1-95.4%); SPECT/CT: 80.0% (49.0-94.3%) and 75.0% (30.1-95.4%). All protocols had perfect sensitivity for detection of parathyroid adenoma whereas SPECT was the most sensitive method for detection of hyperplastic parathyroid glands. CONCLUSION Planar parathyroid scintigraphy using the DT protocol has a trend towards being more accurate than DP and DTDP protocols. Additional imaging with SPECT and SPECT/CT had a trend towards being more accurate than planar imaging.

Detection of lower limb deep vein thrombosis: Comparison between radionuclide venography and venous ultrasonography

Deep vein thrombosis (DVT) is a serious medical condition that needs prompt diagnosis and treatment. The invasive gold standard contrast venography has largely been replaced by venous ultrasonography which is currently the imaging modality of choice for DVT diagnosis. Radionuclide venography (RNV) is an alternative test for DVT, but a few studies have directly compared RNV with venous ultrasonography. This study aims to determine the agreement between RNV and venous ultrasonography for diagnosis of DVT and to determine the predictive value of different RNV findings for the prediction of DVT as detected by venous ultrasonography. Imaging results from patients who underwent both RNV and venous ultrasonography for suspected DVT no more than 1 week apart were reviewed. Results from both modalities were compared to determine inter-modality agreement. A total of 121 venous segments from 102 lower limbs of 75 patients could be compared. The prevalence of DVT as detected by venous ultrasonography was 39%. RNV and venous ultrasonography had moderate agreement (73.6% agreement, κ =0.48, P < 0.0001). The absence of radiotracer activity from a deep venous segment had a positive predictive value (PPV) of 100% for DVT. Other findings such as isolated great saphenous vein activity had a lower PPV. The negative predictive value of RNV is 97.5% with only one patient out of forty with normal RNV found to have DVT by venous ultrasonography, which suggests that DVT can virtually be excluded in patients with normal RNV.

Value of SPECT/CT in Diagnostic I-131 MIBG Scintigraphy in Patients with Neuroblastoma

PurposeDiagnostic I-131 MIBG scintigraphy is an important imaging modality for evaluation of patients with neuroblastoma (NB) especially in centers where I-123 MIBG is not available. Single photon emission computed tomography/computed tomography (SPECT/CT) could potentially improve lesion detection over planar scintigraphy, but studies regarding its usefulness as an add-on to diagnostic I-131 MIBG scintigraphy are limited. This study aimed to determine the usefulness and factors related to usefulness of SPECT/CT in diagnostic I-131 MIBG scintigraphy in NB patients.MethodsUsefulness of SPECT/CT for lesion detection, lesion localization, resolving suspicious findings, and clarifying the nature of lesions on anatomical imaging were retrospectively reviewed in 86 diagnostic planar I-131 MIBG scintigrams with add-on SPECT/CT.ResultsSPECT/CT detected additional lesions in 23.2%(20/86), helped localize lesions in 21.1%(8/38), resolved suspicious findings in 85.7%(6/7), determined functional status of lesions on anatomical imaging in 94.4%(17/18), and changed diagnosis from a negative to a positive study in 19.5%(8/41). Independent predictors of SPECT/CT being useful included presence of suspicious findings on planar imaging (OR 99.08; 95% C.I. 6.99–1404.41; p = 0.001), positive findings on planar imaging (OR 4.61; 95% C.I. 1.05, 20.28; p < 0.001), and presence of structural lesions on anatomical imaging (OR 32.54; 95% C.I. 5.37–196.96; p < 0.001).ConclusionSPECT/CT is a useful add-on to diagnostic planar I-131 MIBG scintigraphy. Predictors of usefulness of SPECT/CT include suspicious or positive findings on planar scintigraphy and the presence of structural lesions on anatomical imaging.