Preoperative imaging in primary hyperparathyroidism: Are 11 C-Choline PET/CT and 99m Tc-MIBI/123 Iodide subtraction SPECT/CT interchangeable or do they supplement each other?

OBJECTIVE: Preoperative location of hyperfunctioning parathyroid glands (HPGs) is vital when planning minimally invasive surgery in patients with primary hyperparathyroidism (PHPT). Dual-isotope subtraction scintigraphy with 99m Tc-MIBI/123 Iodide using SPECT/CT and planar pinhole imaging (Di-SPECT) has shown high sensitivity, but is challenged by high radiation dose, time consumption and cost. 11 C-Choline PET/CT (faster with a lower radiation dose) is non-inferior to Di-SPECT. We aim to clarify to what extent the two are interchangeable and how often there are discrepancies. DESIGN: This is a prospective, GCP-controlled cohort study. PATIENTS AND MEASUREMENTS: One hundred patients diagnosed with PHPT were included and underwent both imaging modalities before parathyroidectomy. Clinical implications of differences between imaging findings and negative imaging results were assessed. Surgical findings confirmed by biochemistry and pathology served as reference standard. RESULTS: Among the 90 patients cured by parathyroidectomy, sensitivity was 82% (95% confidence interval [CI]: 74%-88%) and 87% (95% CI: 79%-92%) for Choline PET and Di-SPECT, respectively, p = .88. In seven cases at least one imaging modality found no HPG. Of these, neither modality found any true HPGs and only two were cured by surgery. When a positive finding in one modality was incorrect, the alternative modality was correct in approximately half of the cases. CONCLUSION: Choline PET and Di-SPECT performed equally well and are both appropriate as first-line imaging modalities for preoperative imaging of PHPT. When the first-line modality fails to locate an HPG, additional preoperative imaging with the alternate modality offers no benefit. However, if parathyroidectomy is unsuccessful, additional imaging with the alternate modality has merit before repeat surgery.

Impact of ictal subtraction SPECT and PET in presurgical evaluation.

OBJECTIVE: To assess the relative contribution of ictal subtraction single-photon emission computed tomography (ISSPECT) and 18 F-fluorodeoxyglucose positron emission tomography computed tomography (PET) in epilepsy surgery decision making. MATERIALS AND METHODS: A retrospective 3-year study of consecutive patients with resistant focal epilepsy who underwent ISSPECT and PET to evaluate to what extent these modalities influence decisions in epilepsy surgery and outcomes. ISSPECT imaging was performed in 106 patients and 58 (55%) had PET also. The clinical consensus (ClinC) was the final arbiter for decisions. Post-surgical outcomes were collected from follow-up clinics. Non-parametric statistics were used to assess association and logistic regression to evaluate prediction of outcomes. RESULTS: Of 106 patients, 60 were males (57%). MRI was non-lesional in 46 (43%). Concordance with ClinC was seen in 80 patients (76%) for ISSPECT, in 46 patients (79%) for PET, and in 37 patients (64%) for ISSPECT + PET. Fifty-six patients (53%) were planned for intracranial video-electroencephalography monitoring (IVEM). Those with ClinC-PET concordance were likely to proceed to IVEM (p = 0.02). ClinC-PET concordance and ClinC-ISSPECT concordance did not predict decision to proceed to surgery, but VEM-MRI concordance did in lesional cases (p = 0.018). Forty-five (42%) underwent surgery of which 29 had minimum follow-up for 1 year (mean, 20 months; SD, 8) and 22 (76%) had Engel class I outcomes. ClinC-ISSPECT concordance (p = 0.024) and VEM-MRI concordance (p = 0.016) predicted Engel class I outcomes. CONCLUSION: Those with ClinC-PET concordance were more likely to proceed with IVEM. ClinC-ISSPECT concordance and VEM-MRI concordance predicted good surgical outcomes.

11C-Choline PET/CT vs. 99mTc-MIBI/123Iodide Subtraction SPECT/CT for Preoperative Detection of Abnormal Parathyroid Glands in Primary Hyperparathyroidism: A Prospective, Single-Centre Clinical Trial in 60 Patients.

BACKGROUND: In patients with primary hyperparathyroidism (PHPT) locating hyperfunctioning glands (HPGs) is crucial when planning minimally invasive surgery. Dual-isotope subtraction scintigraphy with 99mTc-MIBI/123Iodide using SPECT/CT and planar pinhole imaging (Method A) has previously shown a sensitivity >93%. However, the method is costly and time consuming and entails a high radiation dose. 11C-Choline PET/CT (Method B) is an appealing candidate method unencumbered by these disadvantages. METHODS: Sixty patients with newly diagnosed PHPT participated and were scanned using both methods prior to parathyroidectomy. We investigated whether sensitivities of Method A and Method B are similar in a method-to-method comparison when using surgical findings as the true location. RESULTS: At the patient level, sensitivities were (A) 0.98 (95% CI: 0.90-1.00) and (B) 1.00 (95% CI: 0.93-1.00). At the gland level, sensitivities were (A) 0.88 (95% CI: 0.78-0.94) and (B) 0.87 (95% CI: 0.76-0.92). With a non-inferiority margin of ∆ = -0.1, we found a 1-sided p-value < 0.001. CONCLUSION: Our methods comparison study found that sensitivity of Method B was not inferior to Method A. We suggest that 11C-Choline PET/CT is a clinically relevant first-choice candidate for preoperative imaging of PHPT and that Method B can likely replace Method A in the near future.

Added Value of Subtraction SPECT/CT in Dual-Isotope Parathyroid Scintigraphy.

BACKGROUND: Adding subtraction single-photon emission computed tomography/computed tomography (SPECT/CT) to dual isotope (I-123 and Tc-99m-sestamibi) subtraction parathyroid scintigraphy is not widely implemented. We aimed to assess the added value of dual isotope subtraction SPECT/CT over single isotope SPECT/CT as an adjunct to dual isotope planar pinhole subtraction scintigraphy. METHODS: Parathyroid scintigraphies from 106 patients with an estimated total of 415 parathyroid glands who (1) were diagnosed with primary hyperparathyroidism, (2) underwent dual isotope subtraction scintigraphy in the Department of Nuclear Medicine, Gentofte Hospital, Denmark throughout 2017 and (3) underwent subsequent parathyroidectomy, were included. The original dual isotope planar pinhole subtraction plus dual isotope subtraction SPECT/CT (dual/dual method) exams were retrospectively re-evaluated using only Tc-99m-sestamibi SPECT/CT (dual/single method). Statistics were calculated per parathyroid. Surgical results confirmed by pathology served as reference standard. RESULTS: The dual/dual method had higher sensitivity than the dual/single method (82% (95%CI 74%-88%) vs. 69% (95%CI 60%-77%)) while specificity, positive and negative predictive values (PPV and NPV) were similar (specificity 96% vs. 93%, PPV's 87% vs. 82% and NPV's 89% vs. 93%). Reader confidence was higher when employing the dual/dual method (p = 0.001). CONCLUSIONS: The dual/dual method can be considered superior to the dual/single method in the preoperative imaging in primary hyperparathyroidism.

Partial seizures presented as apnea in an adult

Although several cases of apneic seizures have been reported in neonates, epileptic seizures presented with apnea only in adults are very rare. We present a 19-year-old man who suffered from viral encephalitis and frequent episodes of apneic seizures. Ictal EEGs, recorded during apneic episodes, showed repetitive sharp waves or rhythmic theta activ-ities arising from the left or right independent bitemporal region. Ictal SPECT was performed during one episode of apnea accompanied by ictal EEG discharges arising from the left posterior temporal area. Ictal-interictal subtraction SPECT coregistered with MRI revealed that the seizures were originated from the left posterior mid-lateral temporal cortex. Previous studies, with ictal EEG or brain stimulation, suggested that apneic seizures might be mediated through the limbic and the associated cortical systems. This is a very rare case of partial seizures presented with apnea in an adult patient, which was supported by ictal EEG and ictal-interictal subtraction SPECT coregistered with MRI.

Optimization of Subtraction Brain Perfusion SPECT with Basal / Acetazolamide Consecutive Acquisition / 대한핵의학회잡지

This study investigated the method to adjust acquisition time(a) and injection dose(i) to make the best basal and subtraction images in consecutive SPECT. Image quality was assumed to be mainly affected by signal to noise ratio(S/N). Basal image was subtracted from the second image consecutively acquired at the same position. We calculated S/N ratio in basal SPECT images(S1/N1) and subtraction SPECT images(Ss/Ns) to find a(time) and i(dose) to maximize S/N of both images at the same time. From phantom images, we drew the relation of image counts and a(time) and i(dose) in our system using fanbeam-high-resolution collimated triple head SPECT. Noise by imaging process depended on Poisson distribution. We took maximum tolerable duration of consecutive acquisition as 30 minutes and maximum injectible dose as 1,850MBq(50 mCi)(sum of two injections) per study. Counts of second-acquired image(S2), counts(Ss) and noise(Ns) of subtraction SPECT were as follows. C1 was the coefficient of measurement with our system.