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Ectopic thyroid tissue is a rare congenital anomaly, with the presence of three simultaneous ectopic foci being exceedingly rare. We describe a case of a totally asymptomatic 26-year-old male discovered to have triple ectopic thyroid following incidental elevated thyroid-stimulating hormone (TSH) levels. Subsequent ultrasonography of the neck showed an absent thyroid gland in its conventional location. A Technetium-99m pertechnetate (Tc-99m) thyroid scan showed three distinct foci of radiotracer uptake in the upper cervical, lingual, and sublingual regions, corresponding to triple ectopic thyroid. An extensive review of the literature was conducted to provide a broader understanding and deeper insights into this uncommon condition. This case underscores the pivotal role of Technetium-99m thyroid scanning in diagnosing triple ectopic thyroid, particularly in instances where the orthotopic thyroid gland is absent. A comprehensive understanding of this rare entity is indispensable for radiologists and clinicians, enabling accurate diagnosis and informed decision-making regarding the appropriate therapeutic strategies.

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Background: Testicular torsion (TT) is a urological emergency that needs early diagnosis and intervention to prevent testicular death and necrosis. This study aimed to determine the efficacy of testicular scintigraphy (TS) in confirming the clinical diagnosis of TT and how this imaging method correlates with the surgical findings. Methods: A retrospective cohort review of clinical data was performed for 68 patients referred for TS from January 2016 to December 2021 to rule out possible TT. The final diagnosis was confirmed at surgery for all those with TS positive for TT. Results: The median age of the patients was 18.5 years, interquartile range of 15-31 years. Commonly presenting symptoms were pain (99%) and swelling (68%). Only 6% had history of trauma. TT was diagnosed by technetium-99m (99mTc)-pertechnetate in 35 (51%) patients all of whom underwent surgical exploration. Of this group, 7 (20%) had manual detorsion intraoperatively (intermittent torsion), in 20 (57%) missed (complete) torsion was confirmed and 8 (23%) had a necrotic testis. Of the remaining 33 patients with results negative for torsion, 10 were normal and 23 were diagnosed with either epididymitis 13/23 (57%), orchitis 3/23 (13%) or 7/23 (30%) with epididymo-orchitis. TT was more common in patients under 15 and 15-19 years (P<0.05). The mean presentation time was 5 days with a range of 1-30 days. Conclusions: The 99mTc-pertechnetate scan remains an effective investigation in the diagnosis of TT and may serve as a gate-keeper for surgery even in patients who present late for treatment.

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Ectopic thyroid tissue can be present in the embryonal path of descent of the thyroglossal duct anywhere from the foramen caecum to the thyroid gland. However, for such ectopic thyroid tissue to be hyperfunctioning is quite rare. Here, we discuss a 56-year-old female patient who presented with persistent thyrotoxicosis for over 7 years. She had undergone thyroidectomy in 1982 for thyrotoxicosis and was rendered hypothyroid (thyroid-stimulating hormone of 75 µIU/mL). Whole-body technetium scan was done twice which did not show any uptake in the neck or other parts of the body and an empirical dose of 15 mCi of radioiodine therapy was also given to treat the thyrotoxicosis. She continued to be thyrotoxic and was on carbimazole 30 mg/day along with beta-blockers. In 2021, an Iodine131 whole-body scan revealed small remnant thyroid tissue and an ectopic thyroid tissue in a thyroglossal cyst. In such cases of persistent or recurrent thyrotoxicosis despite standard treatments, an ectopic location should be sought after and treated.

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Technegas was developed in Australia as an imaging radioaerosol in the late 1980s and is now commercialized by Cyclomedica, Pty Ltd. for diagnosing pulmonary embolism (PE). Technegas is produced by heating technetium-99m in a carbon crucible for a few seconds at high temperatures (2750 °C) to generate technetium-carbon nanoparticles with a gas-like behaviour. The submicron particulates formed allow easy diffusion to the lung periphery when inhaled. Technegas has been used for diagnosis in over 4.4 m patients across 60 countries and now offers exciting opportunities in areas outside of PE, including asthma and chronic obstructive pulmonary disease (COPD). The Technegas generation process and the physicochemical attributes of the aerosol have been studied over the past 30 years in parallel with the advancement in different analytical methodologies. Thus, it is now well established that the Technegas aerosol has a radioactivity aerodynamic diameter of <500 nm and is composed of agglomerated nanoparticles. With a plethora of literature studying different aspects of Technegas, this review focuses on a historical evaluation of the different methodologies' findings over the years that provides insight into a scientific consensus of this technology. Also, we briefly discuss recent clinical innovations using Technegas and a brief history of Technegas patents.

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Meckel diverticulum, the most common congenital anomaly of the gastrointestinal tract, results from the aberrant involution of the omphalomesenteric duct and accounts for more than 50% of unexplained lower gastrointestinal bleeding in the pediatric population. The most accurate imaging tool to identify a Meckel diverticulum containing ectopic gastric mucosa is the Technetium-99m pertechnetate Meckel scan, a scintigraphic study with a reported accuracy of 90% in the pediatric population. In addition to depicting a Meckel diverticulum with ectopic gastric mucosa, careful attention to the normal biodistribution of the radiotracer can lead to the identification of unexpected pathology with implications for patient management. This article serves to review the embryological origin and anatomical features of Meckel diverticulum, highlight the role of scintigraphy in evaluating Meckel diverticulum, and discuss the proper imaging technique when performing this test. We will focus on pitfalls that can lead to an erroneous diagnosis as well as incidental findings that can affect patient management.

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Context: The impaired ability of thyroid cancer (TC) cells to uptake and concentrate iodine represents a major therapeutic challenge in malignant TC management. This has been reported probably due to reduced or loss of expression of pendrin in thyroid tumors. Aims: In view of this, we evaluated the pendrin expression in the chemically induced (using N-bis[2-hydroxypropyl] nitrosamine [DHPN]) TC model in Wistar rats. Methods: Uptake in the thyroid gland was evaluated by positron emission tomography with computed tomography (PET-CT) and scintigraphy imaging. Further histopathology (HP) and immunohistochemistry (IHC) were performed for confirming malignancy. Results: The altered uptake in the thyroid gland was observed by PET-CT and scintigraphy imaging. Significant pathological changes in the thyroid were observed using 2-deoxy-2-(fluorine-18) fluoro-D-glucose PET-CT, technetium-99m pertechnetate imaging, and reduced iodine-131 uptake (n = 4) in DHPN-induced animals compared to control indicative of thyroid cell proliferation. In treated groups, tissue HP revealed hyperplastic follicular to papillary cell proliferation with variable mitotic activity. The malignant nature of the tissue and variable uptake of the tracer were further reconfirmed by IHC. IHC revealed reduced pendrin expression in malignant thyroid tissue. Conclusions: Hence, nuclear imaging techniques can be of aid in the early identification and evaluation of cellular changes during the early development of tumor models in laboratory animals. In conclusion, our study reveals that pendrin expression plays a vital role in thyroid uptake, and its reduction was observed in TC in a chemically induced TC model.

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PURPOSE: This study investigated the characteristics, diagnosis, and treatment of Warthin tumors (WTs) to explore the possibility of managing patients by observation. METHODS: We reviewed the records of 1167 patients with benign parotid tumors who were seen in our department between September 1999 and April 2021. Among them, 387 cases were WT and 668 cases were pleomorphic adenoma. We evaluated preoperative diagnoses of WT by symptoms/signs, fine-needle aspiration cytology (FNAC), imaging, such as ultrasonography and magnetic resonance imaging, and technetium-99m pertechnetate (Tc-99m) scintigraphy. Fisher's exact test and the Mann-Whitney U test were used in statistical analyses. RESULTS: Warthin tumors were treated by surgery in 238 cases and follow-up in 149 cases. The 238 patients were diagnosed as WT at the final pathology after surgery. Among them, 172 patients (72.3%) were determined as benign histological type by preoperative FNAC; in these 172 patients, 170 (71.4%) were correctly diagnosed as WT in the final pathology. Preoperative Tc-99m scintigraphy was performed in 69 patients diagnosed with WT by final pathology or FNAC, and the positive rate of Tc-99m scintigraphy in WT was 75.4%. CONCLUSIONS: Combining FNAC and Tc-99m scintigraphy, as well as considering clinical findings, enables the diagnosis of WT in most cases. In particular, WT is more common in the elderly, grows more slowly, and is less likely to be malignant. Therefore, if WT can be diagnosed preoperatively with a high rate of correct diagnosis, it could be an accurate and effective means of managing patients through follow-up without surgery.

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AIM: Hepatic venous pressure gradient (HVPG) measurement is a gold standard for the diagnosis of portal hypertension but can be invasive and difficult to conduct. Per-rectal portal scintigraphy (PRPS) can estimate portal haemodynamics noninvasively. However, no report to date has examined the association between HVPG and PRPS in patients with chronic liver disease, including cirrhosis. METHODS: This single-centre study included a total of 21 patients with chronic liver disease who underwent HVPG measurement and PRPS. For PRPS, the transit times from injection of the radiotracer to its inflow into the liver (TTL) and heart (TTH) were set and the time difference between TTL and TTH (TDLH) was calculated, while the shunt index (SI) was measured. RESULTS: Cirrhosis was observed in 18 cases (86%), and the median HVPG was 13 mmHg. HVPG (p = 0.028), TTL (p = 0.018), TDLH (p = 0.003) and SI (p = 0.033) were higher in patients with oesophageal varices (EV). Considering the diagnostic ability for EV, the area under the curve was 0.88 for TDLH and 0.80 for HVPG. TDLH was significantly correlated with the risk of EV rupture (p = 0.004). CONCLUSION: Patients with chronic liver disease should undergo upper gastrointestinal endoscopy when the TDLH is high.

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Subacute thyroiditis (SAT) is one of the most common causes of thyrotoxicosis. Thyroid scans with radioiodine or technetium-99m pertechnetate (99mTc) are often performed in the workup of patients with thyrotoxicosis, particularly to differentiate between SAT and Graves's disease. Although very helpful, thyroid scans are prone to pitfalls that may occasionally lead to misdiagnosis. These pitfalls are largely related to physiologic uptake of radioiodine or 99mTc in non-thyroidal tissue, such as salivary gland and stomach that may result in false-positive findings. We present herein a very rare case of SAT misdiagnosed as an autonomous thyroid adenoma most likely due to focal 99mTc uptake in the esophagus. This case may have implications for the management of patients with suspected SAT, who undergo a radioiodine or 99mTc thyroid scan.

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A method was developed and validated to determine the intradermal (ID) fluid delivery potential of several ID devices, including hollow microneedles. The novel method used water soluble technetium-99 m pertechnetate (99mTcO4-) diluted in normal saline to measure the volume of fluid delivered to and remaining in the skin. The fluid that back-flowed to the skin surface and the fluid left on the device surface were also quantified, thus capturing all fluid volumes deposited during intradermal injections. The technique described in this manuscript was used to assess the injection performance of conventional hypodermic needles and hollow microneedles ex vivo using porcine skin and in vivo with a rat model. Since only a small fraction, 1.1%, of the water-soluble tracer remained bound to the skin when applied topically, the technique can be used to differentiate between injected fluid and backflow. Counting of gamma radiation from 99mTcO4- provided sub-nanoliter resolution for volume measurements, making the proposed method powerful, sensitive, and suitable for the assessments of ID injection devices, particularly for vaccine delivery.

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We here report a rare salivary gland tumor, a non-sebaceous lymphadenoma (NSLA), in the parotid gland with positive technetium-99m (99mTc) pertechnetate scintigraphy and cervical masses that was difficult to distinguish from malignant lymphoma preoperatively. A 65-year-old Japanese woman presented to our institution with a painless left parotid mass that had been gradually enlarging for three months. Computed tomography and magnetic resonance imaging showed a solid mass (30 mm) in the tail of the left parotid gland with three swellings (each 10 mm) on the periphery of the parotid gland. A low grade malignant lymphoma was diagnosed by fine needle aspiration cytology. Gallium-67 scintigraphy showed mild positivity. On 99mTc pertechnetate scintigraphy, the mild accumulation remained after oral stimulation with a mixture of ascorbic acid and calcium pantothenate. The patient underwent superficial parotidectomy with removal of the cervical masses. Our findings in this patient suggest that 99mTc positivity may constitute a clue to the preoperative diagnosis of NSLA that has pathologically overlapping sites with Warthin tumor.

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OBJECTIVE: To investigate the accuracy of dual-tracer scintigraphy for locating parathyroid adenomas in patients with primary hyperparathyroidism (PHPT). METHODS: We reviewed 268 patients with PHPT. All patients underwent technetium-99m pertechnetate (99mTcO4-) scintigraphy and technetium-99m methoxyisobutylisonitrile (99mTc-MIBI) dual-tracer scintigraphy of the thyroid and parathyroid glands, respectively. 99mTcO4- planar scintigraphy was carried out initially followed by dual-phase 99mTc-MIBI single-photon emission computed tomography (SPECT)/CT the next day. The findings were combined and interpreted. Individual 99mTc-MIBI and dual-tracer scintigraphy were both analyzed. The sensitivity, specificity, and accuracy were determined in relation to surgical findings. The average interval between scan and surgery was 13 days. RESULTS: The positive and negative predictive values of 99mTc-MIBI SPECT/CT were 92.0% and 71.3%, respectively, and the sensitivity, specificity, and accuracy were 88.3%, 79.2%, and 85.8%, respectively. The positive and negative predictive values of dual-tracer scintigraphy were 96.3% and 82.3%, respectively, and the sensitivity, specificity, and accuracy were 92.9%, 90.3%, and 92.2%, respectively. Youden's index for dual-tracer scintigraphy and 99mTc-MIBI SPECT/CT were 0.83 and 0.63, respectively. CONCLUSIONS: These finding suggest that 99mTcO4- and 99mTc-MIBI dual-tracer scintigraphy is more accurate than other scintigraphy methods for detecting parathyroid adenoma, and may thus be the most suitable imaging technique in patients with PHPT.

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A Meckel's diverticulum was diagnosed by mesenteric angiography in a 34 year-old patient who presented with hematochezia and dropping hemoglobin. The case demonstrates the challenges often encountered in workup of occult gastrointestinal (GI) bleeding, and shows that angiographic diagnosis of Meckel's diverticulum is possible, even in the absence of angiographic evidence of active extravasation. Our patient had a previous non-diagnostic workup including upper and lower endoscopy, videocapsulography, and Technetium-99m pertechnetate (Tc-99m) scintigraphy. Visceral angiogram demonstrated the presence of a persistent vitelline artery, diagnostic of Meckel's diverticulum. While no active extravasation was seen at the time of the angiogram, operative specimen demonstrated a Meckel's diverticulum with ectopic gastric mucosa and intraluminal hemorrhage.

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The aim of the present study was to evaluate the salivary gland dysfunction in patients with uncontrolled type II diabetes using salivary gland scintigraphy and then to compare these ratios with quantitative whole salivary secretion rates. Using a gamma camera (siemens-diacam) equipped with a low energy all-purpose collimator, 32 uncontrolled type II diabetic patients and 30 normal healthy patients were studied by injecting a radio isotope (technetium 99m pertechnetate) about 5 mCi was injected intravenously in to anticubital vein and the activity was measured for the 1(st), 20(th) and 40(th) min. At 20 min after injection, vitamin C chewable tablet was given to stimulate the secretion and continued until the end of the study period (40 min). Before scintigraphy, salivary sampling was carried out in both diabetic and normal individuals in a quiet room, saliva was allowed to accumulate and was expectorated into the collecting vessel approximately once a minute for 15 min and the volume was recorded as Unstimulated salivary flow rate and after 5 min break vitamin C chewable tablet was given to stimulate the secretion and the patient was asked to expectorate the saliva in the collecting vessel for 5 min. The expectorated volume was recorded as stimulated salivary flow rate. The mean of the measurements of scintigraphic ratio and salivary secretion rates were compared using the paired Student's t-test. The scintigraphic mean uptake and excretory ratio (ER) and the salivary flow rates were correlated. The result shows that there was a significant correlation between salivary flow rate and scintigraphic uptake and ER. However, statistically significant result could not be derived as it may be due to smaller sample size and marginal difference in the scintigraphic values between the groups. Salivary gland scintigraphy plays a significant role in the evaluation of salivary gland dysfunction. However, its role as an independent investigative procedure in the evaluation of salivary gland dysfunction requires a study with a larger sample size, may yield a statistical significant result and it can also act as an adjunct along with salivary flow rate procedure.

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A 63-year-old asymptomatic woman with cured Hodgkin diseases presented for restaging. The chest computed tomography showed a mass at the right side of the upper mediastinum. The benignity and the origin of the tissue were unknown. First, we performed a bronchoscopy-guided biopsy but without success. In the next step, we initiated radionuclide imaging with technetium-99m pertechnetate (Tc-99m) and radioiodine (I-123). Low uptake of Tc-99m and intense accumulation of I-123 after 2 and 24 h to the mediastinal mass suggested that the mass was a mediastinal goiter. Based on iodine uptake and the fact that our patient had no symptoms of tracheal compression, we decide to go for a radioiodine therapy.