Lymphoscintigraphy of the Lower Extremities: Discrepancies Between Superficial and Deep Lymphatic Systems.

ABSTRACT: We describe a 57-year-old man with prostate cancer. A radical prostatectomy with a pelvic lymphadenectomy was performed. After 2 years, a mild swelling of the lower extremities appeared, and the patient was referred for lower-limb lymphoscintigraphy. A lymphoscintigraphy of the superficial lymphatic system in the limbs showed prominent, dermal backflow in the area of the right hypogastrium. Lymphoscintigraphy of the deep lymphatic system showed reflux in the left hypogastrium. This discrepancy between the findings in the superficial and deep lower-limb lymphatic systems was explained by asymmetric sampling of the lymph nodes during the lymphadenectomy.

Quantitative analysis in parathyroid adenoma scintigraphy.

OBJECTIVE: Surgery is the only curative treatment for primary hyperparathyroidism. Parathyroid scintigraphy is one method used to preoperatively localize the lesion. We examined time-related changes in radiopharmaceutical uptake in parathyroid adenomas (PTAs) and thyroid gland by quantitative single-photon-emission computed tomography (SPECT) imaging to assess differences between rapid and delayed washout patterns. PATIENTS AND METHODS: The study group consisted of 35 histologically verified PTAs after radio-guided surgery extirpation in 33 patients with primary hyperparathyroidism. Patients underwent a three-phase SPECT/CT study of the neck and upper thorax post 99mTc-methoxyisobutylisonitrile (MIBI) injection. Images were reconstructed using a proprietary ordered-subset-conjugate-gradient-maximization algorithm (Siemens xSPECT Quant). PTAs were divided into those with a rapid (group A) and those with a slow (group B) washout pattern. SUVmax values of PTAs and thyroid gland tissue at 10, 90 and 180 min post 99mTc-MIBI injection were recorded and statistically assessed. Retention indexes related to the early examination were calculated for PTA and thyroid gland (RI-PTA and RI-TG). RESULTS: There were 11 PTAs in group A and 24 in group B. Significant between-group differences in PTA SUVmax and PTA/thyroid gland ratios were observed only at 180 min postinjection (P = 0.0297, P = 0.0222, respectively). RI-PTAs differed significantly at 90 and 180 min postinjection (P = 0.0298, P = 0.0431). No differences in PTA volumes, thyroid gland SUVmax values or RI-TG were observed between the groups. CONCLUSION: PTAs with rapid and slow washout patterns have different characteristics on quantitative analysis in later phases. No significant differences in directly measurable quantitative values (SUVmax, PTA/thyroid gland ratio) at the early stages of multi-phase examination were observed.

Individualised Timing of Radio-Guided Parathyroidectomy Using Multi-Phase SPECT/CT Increases In Vivo Sensitivity and Accuracy and Reduces Operating Time: A Randomised Clinical Trial.

Background: Minimally invasive parathyroidectomy is the preferred treatment for primary hyperparathyroidism. Despite relatively accurate preoperative information, minimally invasive parathyroidectomy can be challenging, especially in the case of small and ectopic adenomas. Radio guidance aids in both in vivo identification and ex vivo confirmation of adenoma. In vivo accuracy is currently not satisfactory. The present study evaluated whether a beneficial effect (increased sensitivity, specificity, accuracy) is obtained with individualised timing of minimally invasive radio-guided parathyroidectomy (MIRGP) using preoperative multi-phase 99mTc-MIBI single photon emission computed tomography (SPECT)/computed tomography (CT). Methods: This randomised clinical trial was conducted from May 2016 to January 2020 in a tertiary referral hospital. Adult patients with primary hyperparathyroidism sent for 99mTc-MIBI SPECT/CT were included consecutively and randomly assigned to conventional (dual-phase) SPECT/CT and conventional MIRGP (group I) or multi-phase SPECT/CT and individualised MIRGP (group II). One hundred of 106 eligible patients were included, and 83 patients underwent complete intervention. Results: A total of 47 patients in group I and 35 patients in group II were analysed. Group II had a shorter operating time (p = 0.003). The in vivo sensitivity and accuracy of radio guidance was 85.1% in group I and 100% in group II (p = 0.046), and 90.4% in group I and 100% in group II (p = 0.021), respectively. We found no difference in the in vivo specificity and ex vivo parameters between groups. Conclusion: Individualised timing increased the in vivo sensitivity and accuracy of radio guidance and reduced operating time, as some parathyroid adenomas rapidly wash out the radionuclide.

Myocardial perfusion imaging parameters: IQ-SPECT and conventional SPET system comparison.

Technological advancement in hardware and software development in myocardial perfusion imaging (MPI) leads to the shortening of acquisition time and reduction of the radiation burden to patients. We compared semiquantitative perfusion results and functional parameters of the left ventricle between new dedicated cardiac system with astigmatic collimators called IQ-SPECT (Siemens Medical Solutions, USA) and conventional single photon emission tomography (SPET) system equipped with standard low energy high resolution collimators. A group of randomly selected 81 patients underwent consecutively the MPI procedure on IQ-SPECT and on conventional SPET systen, both without attenuation correction. The summed scores and the values of the functional parameters of the left ventricle: ejection fraction (EF), end-systolic and end-diastolic volumes (ESV, EDV) received from the automatic analysis software were compared and statistically analyzed. Our results showed that summed scores values were significantly higher for the IQ-SPECT system in comparison to the conventional one. Calculated EF were significantly lower for IQ-SPECT, whereas evaluated left ventricular volumes (LVV) were significantly higher for this system. In conclusion, we recorded significant differences in automatically calculated semiquantitative perfusion and functional parameters when compared uncorrected studies obtained by the IQ-SPECT with the conventional SPET system.