Quantitative Lobar Tc99m-MAA SPECT/CT of the Lung in pre-and post-procedural guidance for Bronchoscopic Lung Volume Reduction.

METHODS: This prospective study included 92 patients who underwent BLVR with quantitative SPECT/CT study pre- and post-procedure between November 2018 and June 2023. The mean age was 70 years (range 56-85). with 51 males and 41 females. SPECT/CT quantified perfusion for each lobe, and the lowest counts/volume ratio determined the procedural target. Postprocedure SPECT/CT assessed total atelectasis and perfusion shifts. The 6-minute walk test and pulmonary function tests were compared pre- and post-BLVR. RESULTS: SPECT/CT-guided BLVR showed clinical benefits (decreased oxygen requirements) and physiological improvements in total lung capacity, forced expiratory volume, and forced vital capacity (P < 0.05). Significant perfusion shifts were observed away from the target lobe, with unique patterns noted for ipsilateral and contralateral nontarget lobes (P < 0.05). CONCLUSION: Quantitative lobar SPECT/CT in preprocedural guidance for BLVR proved useful in identifying suitable targets in multi-lobe homogeneous emphysema, resulting in physiological and clinical improvements for this patient group. The perfusion shift information provided by SPECT/CT offers valuable insights for pulmonologists.

Glucagonlike Peptide-1 Receptor Agonists: The Good, the Bad, and the Ugly-Benefits for Glucose Control and Weight Loss with Side Effects of Delaying Gastric Emptying.

Glucagonlike peptide-1 (GLP-1) receptor agonists (RAs) are being increasingly used for glycemic control in patients with diabetes and for weight loss and weight management in obese subjects. There has been recent public awareness of the potential of GLP-1 RAs to delay gastric emptying and cause gastroparesis. By delaying gastric emptying, these agents can complicate the clinical evaluation of patients on these drugs by affecting diagnostic testing for gastroparesis. This article discusses GLP-1 RAs and their effects on gastric emptying, gastric food retention, and gastroparesis. This article highlights how physicians should be attuned to the gastric side effects of these popular therapeutic agents for blood glucose control in people with diabetes and for weight loss and weight management in obese patients.

99m Tc-Macroaggregated Albumin Liver Lung Shunt Study With Uptake Indicative of Patent Falciform Artery.

ABSTRACT: Intra-arterial injection of radioactive isotope 90-yttrium 90 Y has been used for elective internal radiation therapy for the treatment of localized hepatocellular carcinoma deemed surgically unresectable. It has also been used to treat intrahepatic cholangiocarcinoma and colorectal cancer that has metastasized to the liver. To prepare for 90 Y treatment, preprocedural mapping via hepatic angiography and 99m Tc-macroaggregated albumin liver lung shunt study followed by postprocedural 90 Y SPECT/CT is essential to ensure a targeted therapy. Therapy is contraindicated if lung shunt fraction is greater than 20% for SIR-Spheres. Anatomic variation in hepatic angiography may be present that can lead to complications if unaccounted for.

Mentorship in Nuclear Medicine-Why and How?

ABSTRACT: Mentorship is a highly gratifying relationship that requires commitment from all involved parties. Several different mentorship models exist that can be modified to suit the requirements of the mentors and mentees, and be fine-tuned for individuals at different career levels. Our proposed framework can be deployed as a pilot design for the trainees and early-career faculty members in nuclear medicine with the scope of appropriate timely modifications based on user feedback.

Bilateral Axillary Nodal Uptake on 99m Tc-White Blood Cell Study Secondary to COVID-19 mRNA Vaccination.

ABSTRACT: A 77-year-old man with a history of chronic lower back pain, and prior spinal fusion surgery X2 was referred for 99m Tc-WBC Study for evaluation of worsening back pain and cervical radiculopathy to rule out any signs of infection. The patients white blood cells were tagged with 99m Tc-HMPAO (hexamethylpropylene amine oxime), and planar and SPECT/CT imaging was performed at 4 and 24 hours. 99m Tc-WBC Study showed no abnormal isotope localization in the spine; however, there was an incidental finding of bilateral increased soft tissue uptake in axillary lymph nodes. Medical history revealed intramuscular injection of second and third dose of Moderna mRNA COVID-19 vaccine in bilateral deltoids approximately 11 and 5 months before scan.

Accuracy of 123I Na Thyroid Imaging in calculating thyroid volume.

Introduction: Hyperthyroidism is often managed with radioactive iodine therapy. The dose of 131Iadministered to the patient is determined based on the calculated size of the thyroid gland in gram and 24 hour iodine uptake. Ultrasonography is a validated modality for determination of thyroid volume. Though necessary for assessing degree of 123I uptake, nuclear scintigraphy also allows for the capability of estimating thyroid volume. Here we compare volume measurements calculated based on ultrasonography and nuclear scintigraphy in a cohort of hyperthyroid patients. Methods: This prospective study designed to evaluate 110 consecutive hyperthyroidism patients who were undergoing thyroid ultrasound and 123I scintigraphy. Scintigraphy was performed after oral administration of approximately 11 MBq 123Isodium, and uptakes at 2 and 24 hours were measured. At 24 hours, the patients underwent thyroid scan with a nuclear medicine camera with LEHR (low energy high resolution) collimator next to the patient's chin. Thyroid measurements were calculated via the formula for determining a prolate ellipsoid. The formula was modified for RAIU as it is a planar image. Volumes calculated with these two modalities were subsequently analyzed and compared by linear regression. All patients had undergone ultrasonography with an average three months from nuclear scan. All of our patient 131I dosages were based on the thyroid measurements obtained by thyroid scintigraphy. Results: We included 110 patients (95 females, 15 males) with age range 20-95 years and average age 56 +/- 17.4 years old. Diagnoses included 66 patients with nodular goiter, and 44 patients with Graves' Disease. There was a linear relationship between measurement of thyroid gland weight by two modalities which can be explained in the following formula: log US(g) = 0.841 + 0.649*log NM(g). Conclusion: We have validated that this method has helped obtain more accurate measurements of the thyroid gland by thyroid scintigraphy. Additionally, we have derived conversion factors that convert the estimated thyroid volume calculated from thyroid scintigraphy to the expected ultrasound value.

Changes in Lung Perfusion in Patients Treated with Percutaneous Mechanical Thrombectomy for Intermediate-Risk Pulmonary Embolism.

BACKGROUND: Current pulmonary embolism treatment options rely heavily on anatomical clot location. However, anatomical location does not necessarily determine adverse outcomes; rather, clinical severity is secondary to the degree of perfusion impairment. Dual-energy computed tomography pulmonary angiogram (DE-CTPA) can map perfusion at the time of pulmonary embolism diagnosis. Single-photon emission computed tomography ventilation-perfusion scans allow for perfusion tracking similar to DE-CTPA. METHODS: We present 3 patients with intermediate-risk pulmonary embolism treated with mechanical thrombectomy using the Inari FlowTriever System (Inari Medical, Irvine, Calif). Lung perfusion scoring was applied to pre-procedure and post-procedure imaging. We graded perfusion of each lobe in 3 planes. If the entire lobe was perfused, a score of 3 was assigned. If lung perfusion is normal, total perfusion score is 15. All patients had pre-procedure and follow-up transthoracic echocardiograms. RESULTS: All 3 patients were diagnosed with pulmonary embolism via DE-CTPA that showed right ventricle strain and had deep venous thrombosis. Following mechanical thrombectomy, patients immediately experienced improvement in perfusion score; scores continued to improve at follow-up. All patients also had improvement in right ventricle size or function on follow-up echocardiogram. DISCUSSION: Intermediate-risk pulmonary embolism often has large initial clot burden that predicts residual pulmonary vascular obstruction. Residual pulmonary vascular obstruction is associated with increased risk of death, recurrent thrombus, and chronic thromboembolic pulmonary hypertension. Clot removal via thrombectomy may decrease the prevalence of residual pulmonary vascular obstruction by improving lung perfusion. We found that mechanical thrombectomy increased lung perfusion immediately and at follow-up assessments.

Thyroid Scintigraphy of a Rare Case of Left Thyroid Lobe Hemiagenesis With Subacute Thyroiditis.

ABSTRACT: Thyroid hemiagenesis is a rare developmental anomaly. Patients with thyroid hemiagenesis have higher incidence of coexisting thyroid disorders in the remaining lobe. We present a rare case of a 21-year-old woman with subclinical hyperthyroidism incidentally found to have thyroid hemiagenesis on thyroid 123I-Na scan, which is confirmed on thyroid ultrasound. On scintigraphy, only the right lobe showed activity. Thyroid ultrasound demonstrated that the right lobe was normal without any nodule. The left lobe was not visualized. This patient's thyroid uptake and scan also revealed low uptake in the remaining right thyroid lobe in keeping with subacute thyroiditis.

Esophageal Oligometastases of the Foot.

ABSTRACT: Acrometastasis is a rare clinical entity, estimated to represent less than 0.3% of all bone metastases. Here, we present a case of esophageal cancer that was treated with esophagectomy, chemotherapy, and radiation therapy and developed oligometastases of the foot after 8 years in remission. The patient developed pain and swelling in his left ankle and foot as the presenting symptom. He underwent radiography and MRI of the affected area, which revealed the lesion. A 99mTc-MDP whole-body bone scan did not reveal any other sites of metastasis.

False-Positive 123I-Uptake Mimics Metastatic Lung Disease in a Patient With Interstitial Lung Disease Secondary to Scleroderma.

ABSTRACT: A 59-year-old woman with a history of papillary thyroid cancer status post total thyroidectomy and 131I ablation therapy presented with lower back pain and leg weakness. MRI of the lumbar spine revealed homogenously enhancing lesions at L1-L2 and L3-L4. Subsequent whole-body 123I-Na scan demonstrated significant 123I retention in the mid to distal esophagus, as well as diffuse uptake in basal segments of the lungs bilaterally. SPECT/CT of the lumbar vertebra was unremarkable. Although 123I-Na uptake often indicates metastatic recurrence, these findings were better explained by nonspecific radioiodine uptake secondary to systemic complications of the patient's underlying scleroderma.

The Utility of Adding a Liquid-Nutrient Meal to Aid Interpretation of Small-Bowel Transit Scintigraphy.

Small-bowel transit scintigraphy (SBTS) evaluates the accumulation of a radiolabeled meal in the terminal ileal reservoir (TIR) 6 h after ingestion. The location of the TIR may be difficult to determine because anatomic information is limited; for equivocal studies, the patient is asked to return the next day to help determine the TIR location by potential transit into the colon. The purpose of this study was to evaluate whether administration of an additional liquid-nutrient meal (LNM) at 6 h can promote movement of the radiolabeled meal to aid in the interpretation of SBTS and eliminate the need for the patient to return. Methods: This retrospective study reviewed 117 SBTS studies from February 2017 to September 2019. Patients were fed a standardized mixed radiolabeled solid-liquid meal for gastric emptying with SBTS according to Society of Nuclear Medicine and Molecular Imaging practice guidelines. An additional LNM was given at 6 h, and post-LNM images were obtained at least 20 min after the LNM. Two board-certified nuclear medicine physicians independently evaluated all images as equivocal or diagnostic at 6 h. Results: Of the 117 patients (71.8% female; median age, 42.0 y) undergoing SBTS, 37 were equivocal cases at 6 h before the LNM (31.6%; 95% CI, 23.3%-40.9%), compared with 12 equivocal cases after the LNM (10.3%; 95% CI, 5.4%-17.2%). Of the equivocal cases, 25 (69.4%; 95% CI, 51.9%-83.7%) had a definitive result after the LNM, whereas 11 (30.6%; 95% CI, 16.4%-48.1%) remained equivocal and 1 showed rapid transit. Among the 23 patients with gastroparesis, only 13 (57%) responded to the LNM, and none of the 3 patients with irritable bowel syndrome responded. Conclusion: The number of equivocal SBTS cases decreased after administration of an LNM at 6 h, converting to a definitive result. This suggests that with use of an LNM, most patients can complete SBTS in 1 d without the need for repeat imaging at 24 h. Administering an LNM appears to be less effective for patients with gastric disorders. However, the clinical significance remains to be explored, and it is unclear whether such patients have both a gastric and a small-bowel disorder, hence reducing any motility-promoting effect of the LNM.

Using gastric emptying scintigraphy to evaluate antral contractions and duodenal bolus propagation.

Our aim was to investigate the feasibility of measuring antral contractions and duodenal bolus propagation (DBP) during dynamic antral contraction scintigraphy (DACS) as an assessment of antro-pyloro-duodenal coordination (APDC). Gastric emptying scintigraphy (GES) with DACS was performed with Tc-99m sulfur colloid (SC) using increasing doses of 74 MBq (2 mCi) for 10 subjects, 185 MBq (5 mCi) for 11, and 370 MBq (10 mCi) for 11. DACS was performed for 10 min after static images at 0, 30, 60, 120, 180, and 240 min in anterior and right anterior oblique (RAO) projections. Best projection and lowest dose of Tc-99m SC were assessed visually. DBP were quantified utilizing duodenal activity peaks from a region of interest in the first portion of the duodenum. DBP was better visualized in the RAO projection than anterior projection and using 185 MBq (5 mCi) and 370 MBq (10 mCi) compared with 74 MBq (2 mCi). DBP showed infrequent and irregular bolus transfers from the antrum to the duodenum. Antral activity peaks at 60 min averaged 2.91 ± 0.66 per minute and duodenum bolus peaks 0.36 ± 0.18 per minute (ratio 0.36/2.91 = 0.12). DBP activity peaks can be measured during GES with DACS but requires a 185-MBq (5 mCi) dose of Tc-99m SC radiolabeled test meal for adequate DBP signal detection and is better imaged in RAO than anterior projection. DBPs over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess APDC.NEW & NOTEWORTHY This study shows that duodenal bolus propagations after meal ingestion can be measured during gastric emptying scintigraphy using dynamic scintigraphy. Duodenal bolus propagation over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess antropyloroduodenal coordination in patients with unexplained symptoms of upper gastrointestinal dysmotility.

Gastric emptying scintigraphy results may influence the selection of the type of bariatric surgery: A cohort study.

Bariatric surgery (BAS) may result in adverse outcomes that include appearance of gastrointestinal (GI) symptoms and/or failure to reach the weight reduction goal. This retrospective study tested the hypothesis that pre-operative gastric emptying (GE) abnormality is responsible for adverse post-surgical outcomes.Pre-operative GE was performed using the standard solid-meal GE scintigraphy (GES) in 111 consecutive patients (105 females and 6 males, mean age 46.2 years, range 20-70 years) who were evaluated for BAS. All underwent BAS - 93 had laparoscopic sleeve gastrectomy (LSG) and 18 had Roux-en-Y (ReY) gastric bypass. All had short-term (3-6 months) and long-term (up to 54 months) follow-up with review of symptoms, physical, and laboratory examinations. Chi-square analysis was performed. P-value < .05 was considered significant.Of the 111 patients, 83 had normal and 28 had abnormal pre-op GES. Sixty-eight were asymptomatic and 43 were symptomatic prior to surgery. Following surgery, 81 patients were asymptomatic and 30 were symptomatic at long-term follow-up. There was no significant difference between pre-op GE results and post-surgical adverse clinical outcome (p = ns). However, GES results seem to have guided the selection of surgical procedure significantly (P = .008).Pre-operative GE study was not a strong predictor of clinical outcome in BAS. Although, it influenced the type of surgery, as when the GES was abnormal, the patient was more likely to undergo ReY and when GES was normal, they favored LSG. Interestingly, many of our symptomatic patients at 6 months post-op were asymptomatic after long-term follow-up.

Clinical Value of Tc99m-MIBI SPECT/CT Versus 4D-CT or US in Management of Patients With Hyperparathyroidism.

Localization of parathyroid adenomas for treatment of primary hyperparathyroidism can be challenging. This retrospective study compared single-photon emission computed tomography/computed tomography (SPECT/CT), 4D-CT, and US studies in detection of adenomas prior to surgery. A retrospective chart review was performed on all consecutive patients with parathyroid adenoma presenting to an urban tertiary care medical center. A total of 58 patients (45 female, 13 male) underwent surgery for parathyroid adenoma. Patients aged 28 to 80 years (mean: 58.8) with parathyroid hormone levels ranging from 42 to 424 pg/mL (mean: 168). All patients underwent preoperative SPECT/CT with 20 mCi technetium-99m MIBI (99mTc-MIBI). Fifty-three patients had additional US imaging and 14 patients had 4D-CT scans. Additionally, 34 patients had injection of 20 mCi 99mTc-MIBI on the day of surgery. Pathological correlation was performed. Comparing SPECT/CT versus 4D-CT resulted in sensitivity (77% vs 80%), specificity (71% vs 75%), and accuracy (77% vs 79%). Ultrasound was less sensitive with similar specificity (44%, 86%, respectively). Combination of SPECT/CT and 4D-CT increased sensitivity to 88%, specificity to 100%, and accuracy to 89%. Combining SPECT/CT with US resulted in sensitivity of 85%, specificity of 83%, and accuracy of 85%. Intraoperative localization substantially improved in patients who received preoperative injections. The SPECT/CT remains the best imaging modality for preoperative localization of parathyroid adenomas with high sensitivity. Combining SPECT/CT with US resulted in increased sensitivity and accuracy. For suspicion of ectopic cases or suspicion of unidentifiable adenoma with negative scintigraphy, addition of 4D-CT is recommended. Intraoperative localization and adjunctive imaging may improve surgical management of patients with hyperparathyroidism.

Does the dose of iodine-131 influence the incidence of Graves' ophthalmopathy?

BACKGROUND: Radioactive iodine-131 (RAI) is an established treatment for patients with Graves' hyperthyroidism. RAI is reported to be associated with a 20-30% incidence of development or exacerbation of Graves' ophthalmopathy (GO). This study compares the progression of GO in patients who had evidence or no evidence of GO before RAI therapy. PATIENTS AND METHODS: Forty-eight patients were studied. One group had no evidence whereas the other group had evidence of GO before RAI treatment. All underwent RAI therapy. Group A (27 patients, 18 women, nine men, age: 19-68 with a mean of 49 years) had pre-existing exophthalmos. Group B consisted of 21 patients (13 women, eight men, age: 30-63 with a mean of 43 years) developed exophthalmos after treatment. All patients underwent RAI therapy and followed by ophthalmologists. RESULTS: The average administered dose in group A was 24.3 mCi (range: 10-36.2 mCi) compared with group B: 25.4 mCi (range: 13-35.9 mCi), P=0.60. Ten (37%) of the 27 patients in group A experienced worsening of symptoms post-treatment. There was no significant difference between the administered dose of RAI in patients with worsening symptoms, 25.1 mCi versus patients with stable symptoms, 24.5 mCi (P=0.82). However, group A developed GO symptoms earlier than group B (4.5 vs. 9.5 months), P=0.02. CONCLUSION: RAI is known to exacerbate ophthalmopathy. Our study showed it was not dose-dependent. Patients without a previous history of GO were observed to have a significantly delayed period for the development of symptoms.

Enhanced Gastric Emptying Scintigraphy to Assess Fundic Accommodation Using Intragastric Meal Distribution and Antral Contractility.

Gastric emptying scintigraphy (GES) as now commonly performed measures only total gastric emptying. Intragastric meal distribution (IMD) immediately after meal ingestion (t = 0 min) (IMD0) can assess fundic accommodation, and dynamic antral contraction scintigraphy (DACS) can assess antral motility. Our goals were to incorporate IMD and DACS into GES, compare IMD0 using gastric division into anatomic proximal and distal halves versus more physiologic separation of the antrum from the proximal stomach using DACS, and establish reference values. Methods: Healthy subjects (n = 20) underwent GES using a solid-liquid meal. DACS (1 frame/3 s) was performed for 20 min after each static imaging time. IMD0 was measured using both semiautomated software to divide the gastric long axis into anatomic halves and Fourier analysis to identify antral pixels with phasic contractions. Results: Using halving of the stomach, IMD0 averaged 0.75 ± 0.15 (SD). Using phasic contractions to define the antrum, mean IMD0 was 0.85 ± 0.14 (P = 0.004). Sustained antral contractions started at a mean of 11.24 ± 12.98 min after meal ingestion and originated in the gastric midbody with a starting location at 40.5% ± 10.8% from the distal to the proximal stomach along its long axis. Antral frequency and ejection fraction peaked 30 min after meal ingestion at 3.30 ± 0.71 contractions per minute and an ejection fraction of 30.3% ± 13.69%, when mean antral filling peaked at 36.7% ± 14%. Maximum antral contraction speed was 3.54 ± 0.90 mm/s at 60 min after meal ingestion. Gastric retention was 39.8% ± 12.8% at 2 h and 5.8% ± 6.0% at 4 h. Conclusion: Addition of DACS to GES permits physiologic characterization of both fundic accommodation and antral contractility to supplement routine GES.