Technetium-99m sestamibi single-photon emission computed tomography/computed tomography (99mTc-sestamibi SPECT/CT) is a mainstay of the pre-operative localization of parathyroid lesions. We report here the case of a 30 year-old woman with a fortuitously discovered 2 cm cervical mass for which a parathyroid origin was originally suspected due to its retro-thyroidal localization and a personal history of nephrolithiasis. Normal serum calcium and parathyroid hormone (PTH) levels excluded primary hyperparathyroidism, raising suspicion of a non-functional parathyroid adenoma, and SPECT/CT imaging showed that the mass was 99mTc-sestamibi-avid. Fine-needle aspiration (FNA) was performed; cytology was non-diagnostic but the needle washout was negative for thyroglobulin, calcitonin and PTH, arguing against a thyroidal or parathyroidal origin of the mass. Core needle biopsy revealed a schwannoma, ostensibly originating from the recurrent laryngeal nerve; upon surgical resection, it was finally found to arise from the esophageal submucosa. This case illustrates the fact that endocrinologists, radiologists, nuclear medicine, head and neck, and other specialists investigating patients with cervical masses should be aware that schwannomas need to be considered in the differential diagnosis of focal 99mTc-sestamibi uptake in the neck region.

UNASSIGNED: This study investigates the new combined parameters of 99mTc-DTPA orbital single-photon emission computed tomography/computed tomography (SPECT/CT) for the evaluation of Graves\' orbitopathy (GO) activity.
UNASSIGNED: A retrospective analysis was performed on 41 patients. All the patients undergone the 99mTc-DTPA orbital SPECT/CT and were categorized into active and inactive group based on the standard combined by the clinical active score (CAS), magnet resonance imaging (MRI) and/or follow-up results. Quantitative parameters of lacrimal gland (LG) including the protruding degree of lacrimal gland herniation (LGH) and uptake ratios (URs) of region of interest (ROI) drawn on lacrimal gland and occipital bone. SPECT/CT reading results were based on visual analysis. Parameters were compared between the two groups and the diagnostic value on discrimination of GO activity was also evaluated.
UNASSIGNED: All parameters of SPECT/CT for active GO groups were significantly higher than those of the inactive groups (p<.05). There were notable linear positive correlations between the assumption standard and readings as well as combination models 2 and 3 (r = .794, r = .772, r = .760, respectively). ROC analysis indicated that model 2 provided the highest diagnostic performance, exhibiting an area under the curve (AUC) of .947, a sensitivity of 92.7%, and a specificity of 88.6%.
UNASSIGNED: The combined use of SPECT/CT reading results and DTPA uptake parameters of LG offers a more objective and precise evaluation of active GO. This study further recommends 99mTc-DTPA SPECT/CT might be serving as a supplementary beneficial approach for CAS in evaluating GO activity.

BACKGROUND: Planar lymphoscintigraphy (PL) is commonly used in mapping before sentinel lymph node biopsy (SLNB) for invasive cutaneous melanoma. Recently, single-photon emission computed tomography (SPECT)/ computed tomography (CT) has been utilized, in addition to PL, for detailed anatomic information and detection of sentinel lymph nodes (SLNs) outside of the primary nodal basin in truncal and head and neck melanoma. Following a protocol change due to COVID-19, our institution began routinely obtaining both PL and SPECT-CT imaging for all melanoma SLN mapping. We hypothesized that SPECT-CT is associated with higher instances of SLNBs from \"nontraditional\" nodal basins (NTNB) for extremity melanomas.
METHODS: Patients with extremity melanoma (2017-2022) who underwent SLNB were grouped into SPECT-CT with PL versus PL alone. Outcomes were total SLNs removed, + or-SLN status, total NTNB sampled, and postoperative complication rate. Poisson regression and logistic regression models were used to assess association of SPECT-CT with patient outcomes.
RESULTS: Of 380 patients with extremity melanoma, 42.11% had SPECT-CT. There were no differences between the groups with regards to age at diagnosis or sex. From 2020 to 2022, all patients underwent SPECT-CT. SPECT-CT was associated with increased odds of SLNB from an NTNB, (odds ratio = 2.39 [95% confidence interval: 1.25-4.67]). There was no difference in odds of number of SLNs sampled, SLN positivity rate, or postoperative complication rate with SPECT-CT.
CONCLUSIONS: Routine SPECT-CT was associated with higher incidence of SLNB in NTNB but did not increase number of SLNs removed or SLN positivity rate. The added value of routine SPECT-CT in cutaneous melanoma of the extremities remains to be defined.

Malignant otitis externa (MOE) with skull base osteomyelitis (SBO) is an aggressive infection that predominantly affects elderly, diabetic, or immunocompromised patients, and is associated with high disease-specific mortality. Pseudomonas aeruginosa is the most isolated microorganism. External otitis associated with granulation tissue and pain is the most common presenting feature; a biopsy is obtained to rule out malignancy. A proper consensus is lacking regarding the best imaging modality for early initial diagnosis and follow-up. 99mTechnetium (99mTc)-labeled ubiquicidin (UBI) 29-41 is a bacterial attaching peptide that does not bind to activated leukocytes. We report a case of SBO initially misdiagnosed as a chronic otitis media, but later proved to be a case of MOE. 99mTc methylene diphosphonate bone scan and 99mTc-UBI 29-41 scan with single-photon emission computed tomography/computed tomography scans were performed to corroborate the clinical diagnosis. SBO remains a great challenge due to its increasing prevalence and high morbidity are difficult to diagnose and are often confused with cholesteatoma and neoplastic process. The UBI scan could be an auxiliary noninvasive diagnostic alternative in early diagnosis.

BACKGROUND: Primary aortoduodenal fistula is a rare cause of gastrointestinal (GI) bleeding consisting of abnormal channels between the aorta and GI tract without previous vascular intervention that results in massive intraluminal hemorrhage.
METHODS: A 67-year-old man was hospitalized for coffee ground vomiting, tarry stools, and colic abdominal pain. He was repeatedly admitted for active GI bleeding and hypovolemic shock. Intermittent and spontaneously stopped bleeders were undetectable on multiple GI endoscopy, angiography, computed tomography angiography (CTA), capsule endoscopy, and 99mTc-labeled red blood cell (RBC) scans. The patient received supportive treatment and was discharged without signs of rebleeding. Thereafter, he was re-admitted for bleeder identification. Repeated CTA after a bleed revealed a small aortic aneurysm at the renal level contacting the fourth portion of the duodenum. A 99mTc-labeled RBC single-photon emission CT (SPECT)/CT scan performed during bleeding symptoms revealed active bleeding at the duodenal level. According to his clinical symptoms (intermittent massive GI bleeding with hypovolemic shock, dizziness, dark red stool, and bloody vomitus) and the abdominal CTA and 99mTc-labeled RBC SPECT/CT results, we suspected a small aneurysm and an aortoduodenal fistula. Subsequent duodenal excision and duodenojejunal anastomosis were performed. A 7-mm saccular aneurysm arising from the anterior wall of the abdominal aorta near the left renal artery was identified. Percutaneous intravascular stenting of the abdominal aorta was performed and his symptoms improved.
CONCLUSIONS: Our findings suggest that 99mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.

UNASSIGNED: The salivagram was first described to detect possible lung aspiration in infants or young children. Its original protocol required dynamic imaging for 60 minutes, which has high sensitivity. The purpose of this retrospective investigation was to determine whether a shortened period of image acquisition can be adopted without significantly reducing the sensitivity of the test in detecting aspiration.
UNASSIGNED: The current salivagram protocol in our hospital requires 60 minutes of dynamic imaging. The images of a total of 398 patients (ages 1 month to 9 years old) with positive salivagrams were analyzed. The entire 60-minute dynamic images were divided into 6 periods, 10 minutes/period. The time of the onset of abnormal activity in the bronchi, which was evidence of aspiration in each patient, was recorded and assigned to the corresponding period.
UNASSIGNED: Among all 398 patients with evidence of aspiration, tracheobronchial tree activity could be seen in the first 10 minutes of the dynamic imaging in 184 of them (46.2%, 184/398). The onset of the bronchial activity was seen between 10 and 20 minutes in 177 patients (44.5%, 177/398). A total of 35 patients (8.8%, 35/398) had the onset of abnormal tracheobronchial tree activity in the 3rd period between 20 and 30 minutes. During the 4th period between 30 and 40 minutes, the onset of the aspiration occurred in only 2 patients (0.5%, 2/398). All patients had the onset of aspiration in the first 40 minutes of the dynamic imaging.
UNASSIGNED: The originally described 60-minute dynamic imaging protocol of the salivagram can be safely shortened to 40 or even 30 minutes without a significantly decreased chance of detecting aspiration. Prolonged imaging is unnecessary.

When visualizing biological activity at nonunion sites by the radioisotopes, gamma rays are more attenuated if metal implants are placed in the bone. However, the effects of various implant types and their placement on gamma ray attenuation in quantitative evaluation remain unknown. To elucidate these effects, we created a phantom that simulated the nonunion of the femur in this study. The count of gamma rays was measured by single-photon emission computed tomography/computed tomography (SPECT/CT) while considering CT-based attenuation correction (CTAC), metal implant placement, type (intramedullary nail or plate), and position. The count differed significantly with and without CTAC and with and without implants (both types) under CTAC. Significantly different counts were observed between the intramedullary nail and plate placed contralaterally to the lesion (i.e., non-lesion side). No significant difference was observed between the intramedullary nail and plate on the lesion side or between plates on the non-lesion and lesion sides. The measured standardized uptake value (SUV) was closer to the true SUV with CTAC than without. Moreover, the count was higher with implants than without. However, even with implants, it was lower than the actual count, indicating the absence of overcorrection. Implant type and position do not seem to influence the count.

Perfusion scintigraphy with the acquisition of planar blood flow and pool images of bilateral hands has been used to aid diagnosis and to evaluate treatment response to Raynaud\'s phenomenon (decreased blood flow to hand or foot). However, because of the difficulty in imaging the tongue area with a conventional gamma camera, perfusion scintigraphy imaging of patients with lingual Raynaud\'s phenomenon has yet to be reported. Here, we report the case of a 59-year-old man with lingual Raynaud\'s phenomenon in which blood pool imaging of the tongue was performed using three-dimensional (3D)-ring cadmium-zinc-telluride (CZT) single-photon emission computed tomography/computed tomography (SPECT/CT). During follow-up, the patient\'s lingual symptoms had worsened, and follow-up blood pool SPECT/CT images also revealed decreased blood pool uptake of the tongue, showing a decreased blood pool of more than 25% on quantitative analysis. This case suggests that blood pool imaging of the tongue using 3D-ring CZT SPECT/CT has clinical significance in evaluating patients with lingual Raynaud\'s phenomenon.

Vertebral tuberculosis (TB) is a common form of extrapulmonary TB. Here, the slow-growing Mycobacterium bacillus reaches the disc space through the hematogenous route and leads to various complications. Radiological imaging and histopathology have been the mainstay of diagnosis, but radionuclide imaging techniques using radiolabeled antitubercular drugs have rarely found space in the clinical domain. Here, we present a case of vertebral TB, where a technetium-labeled antitubercular drug, ethambutol, was synthesized and used for imaging the bacteria in vivo. Thus, we demonstrate a rarely used potentially specific agent for tuberculous-infection imaging, which can be produced in-house, and provides rapid results.

Goiter with an intrathoracic component is relatively common; however, it is less common to see extent outside the anterior or posterior mediastinum. We present a case of intrathoracic goiter of significant size and abnormal placement which is examined using both 99mTc-pertechnetate and iodine-123 single-photon emission computed tomography/computed tomography.