Rare finding of primary aortoduodenal fistula on single-photon emission computed tomography/computed tomography of gastrointestinal bleeding: A case report

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.

CASE SUMMARY

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.

CONCLUSION

Our findings suggest that 99mTc-labeled RBC SPECT/CT scanning can aid the diagnosis of a rare cause of active GI bleeding.

Clinical applications of single-photon emission computed tomography/computed tomography in post-ablation 131iodine scintigraphy in children and young adults with differentiated thyroid carcinoma

BACKGROUND

The utility of integrated single-photon emission computed tomography/computed tomography (SPECT/CT) in children and young adults with differentiated thyroid carcinoma is incompletely studied.

OBJECTIVE

To determine the value of adding SPECT/CT to conventional whole-body scintigraphy in post-ablation iodine-131 (¹³¹I) scintigraphy for children and young adults with differentiated thyroid carcinoma.

MATERIALS AND METHODS

Planar scintigraphy and SPECT/CT were performed on 42 post-surgical children and young adults (32 female, 10 male; mean age 14.3±4.9 years, range 7-20 years) with differentiated thyroid carcinoma (39 papillary, 2 follicular, 1 mixed) 5 days after the therapeutic administration of 1.9-7.4 GBq of ¹³¹I. Planar and SPECT/CT images were interpreted independently, and sites of uptake were categorized as positive or equivocal with respect to thyroid bed, lymph node and distant metastasis uptake. An experienced thyroid endocrinologist used a combination of surgical histopathology and scintigraphic findings to determine whether the addition of SPECT/CT would change patient management.

RESULTS

Planar scintigraphy evidenced 88 radioiodine-avid foci and SPECT/CT confirmed all foci. No additional foci were disclosed by SPECT/CT. SPECT/CT correctly classified 16/88 (18%) foci that were unclear or wrongly classified at planar scintigraphy. Globally, SPECT/CT showed an incremental value over planar scintigraphy in 9 (21.4%) patients and changed therapeutic management in 3 (7.1%; 95% confidence interval, 2-20%) patients.

CONCLUSION

SPECT/CT improved localization and characterization of focal ¹³¹I uptake on post-ablation whole-body scintigraphy in children and young adults with differentiated thyroid carcinoma. Further prospective evaluation in a larger series is justified to prove the effect of post-ablation SPECT/CT-based management decisions.

Comparison of the detecting capability between 123I-mIBG and post-therapeutic 131I-mIBG scintigraphy for curie scoring in patients with neuroblastoma after chemotherapy

OBJECTIVE

To evaluate the detecting capability between planar imaging (PI) and PI combined with single-photon emission computed tomography/computed tomography (PICWS), including ¹²³I- and ¹³¹I-labeled metaiodobenzylguanidine (mIBG) and to compare the detecting capability between ¹²³I-mIBG and post-therapeutic ¹³¹I-mIBG scintigraphy including PI and PICWS for Curie scoring in patients with neuroblastoma.

METHODS

Sixty-two patients with 66 pairs of complete images with neuroblastoma were enrolled in this retrospective study.

RESULTS

Comparing the Curie scoring between ¹²³I-mIBG PI and PICWS and between post-therapeutic ¹³¹I-mIBG PI and PICWS, findings were concordantly negative in 28.79% and 18.18% of studies, concordantly positive in 66.67% and 74.24% of studies, and discordant in 4.54% and 7.58% of studies, respectively. PICWS was superior to PI including ¹²³I- and ¹³¹I-mIBG in the evaluation of Curie scoring for neuroblastoma patients (both P < 0.001). Comparing the Curie scores between ¹²³I- and post-therapeutic ¹³¹I-mIBG PI and between ¹²³I- and post-therapeutic ¹³¹I-mIBG PICWS, concordantly negative imaging was visualized in 22.73% and 19.70% of studies, concordantly positive imaging in 66.67% and 69.70% of studies, and discordant imaging in 10.60% and 10.60% of studies, respectively. Post-therapeutic ¹³¹I-mIBG was significantly better than that of ¹²³I-mIBG scintigraphy including PI and PICWS in detecting the Curie scoring for neuroblastoma patients (both P < 0.001).

CONCLUSION

The present study demonstrates that ¹³¹I- or ¹²³I-mIBG PICWS are more helpful in the evaluation of Curie scores than that of conventional PI and that post-therapeutic ¹³¹I-mIBG is superior to ¹²³I-mIBG scintigraphy for the detecting capability of Curie scoring in patients with neuroblastoma.

A Prospective Comparison of 18F-prostate-specific Membrane Antigen-1007 Positron Emission Tomography Computed Tomography, Whole-body 1.5 T Magnetic Resonance Imaging with Diffusion-weighted Imaging, and Single-photon Emission Computed Tomography/Computed Tomography with Traditional Imaging in Primary Distant Metastasis Staging of Prostate Cancer (PROSTAGE)

BACKGROUND

Computed tomography (CT) and bone scintigraphy (BS) are the imaging modalities currently used for distant metastasis staging of prostate cancer (PCa).

OBJECTIVE

To compare standard staging modalities with newer and potentially more accurate imaging modalities.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, single-centre trial (NCT03537391) enrolled 80 patients with newly diagnosed high-risk PCa (International Society of Urological Pathology grade group ≥3 and/or prostate-specific antigen [PSA] ≥20 and/or cT ≥ T3; March 2018-June 2019) to undergo primary metastasis staging with two standard and three advanced imaging modalities.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The participants underwent the following five imaging examinations within 2 wk of enrolment and without a prespecified sequence: BS, CT, ^99mTc-hydroxymethylene diphosphonate (^99mTc-HMDP) single-photon emission computed tomography (SPECT)-CT, 1.5 T whole-body magnetic resonance imaging (WBMRI) using diffusion-weighted imaging, and ¹⁸F-prostate-specific membrane antigen-1007 (¹⁸F-PSMA-1007) positron emission tomography(PET)-CT. Each modality was reviewed by two independent experts blinded to the results of the prior studies, who classified lesions as benign, equivocal, or malignant. Pessimistic and optimistic analyses were performed to resolve each equivocal diagnosis. The reference standard diagnosis was defined using all available information accrued during at least 12 mo of clinical follow-up. Patients with equivocal reference standard diagnoses underwent MRI and/or CT to search for the development of anatomical correspondence. PSMA PET-avid lesions without histopathological verification were rated to be malignant only if there was a corresponding anatomical finding suspicious for malignancy at the primary or follow-up imaging.

RESULTS AND LIMITATIONS

Seventy-nine men underwent all imaging modalities except for one case of interrupted MRI. The median interval per patient between the first and the last imaging study was 8 d (interquartile range [IQR]: 6-9). The mean age was 70 yr (standard deviation: 7) and median PSA 12 ng/mL (IQR:7-23). The median follow-up was 435 d (IQR: 378-557). Metastatic disease was detected in 20 (25%) patients. The imaging modality ¹⁸F-PSMA-1007 PET-CT had superior sensitivity and highest inter-reader agreement. The area under the receiver-operating characteristic curve (AUC) values for bone metastasis detection with PSMA PET-CT were 0.90 (95% confidence interval [CI]: 0.85-0.95) and 0.91 (95% CI: 0.87-0.96) for readers 1 and 2, respectively, while the AUC values for BS, CT, SPECT-CT, and WBMRI were 0.71 (95% CI: 0.58-0.84) and 0.8 (95% CI: 0.67-0.92), 0.53 (95% CI: 0.39-0.67) and 0.66 (95% CI: 0.54-0.77), 0.77 (95% CI: 0.65-0.89) and 0.75 (95% CI: 0.62-0.88), and 0.85 (95% CI: 0.74-0.96) and 0.67 (95% CI: 0.54-0.80), respectively, for the other four pairs of readers. The imaging method ¹⁸F-PSMA-1007 PET-CT detected metastatic disease in 11/20 patients in whom standard imaging was negative and influenced clinical decision making in 14/79 (18%) patients. In 12/79 cases, false positive bone disease was reported only by PSMA PET-CT. Limitations included a nonrandomised study setting and few histopathologically validated suspicious lesions.

CONCLUSIONS

Despite the risk of false positive bone lesions, ¹⁸F-PSMA-1007 PET-CT outperformed all other imaging methods studied for the detection of primary distant metastasis in high-risk PCa.

PATIENT SUMMARY

In this report, we compared the diagnostic performance of conventional and advanced imaging. It was found that ¹⁸F-prostate-specific membrane antigen-1007 positron emission tomography/computed tomography (¹⁸F-PSMA-1007 PET-CT) was superior to the other imaging modalities studied for the detection of distant metastasis at the time of initial diagnosis of high-risk prostate cancer. PSMA PET-CT also appears to detect some nonmetastatic bone lesions.

Accuracy of Dual Phase Single-Photon Emission Computed Tomography/Computed Tomography in Primary Hyperparathyroidism: Correlation With Serum Parathyroid Hormone Levels

PURPOSE

The objectives of this study were: 1) to determine the accuracy of dual-phase (99m)Tc -methoxyisobutylisonitrile (MIBI) with single-photon emission computed tomography/computed tomography (SPECT/CT) for the preoperative localization of parathyroid adenomas in the setting of primary hyperparathyroidism; 2) to determine the accuracy of localization for ectopic glands; and 3) to assess the relationship between accuracy and serum parathyroid hormone (PTH) levels.

METHODS

Eighty-eight patients who underwent (99m)Tc-MIBI SPECT/CT imaging for primary hyperparathyroidism at our institution over a 27-month period were retrospectively assessed. The preoperative SPECT/CT results were compared to intraoperative findings (within 1 year of imaging). The relationship between serum PTH level (within 3 months) and SPECT/CT accuracy was then evaluated.

RESULTS

Accuracy indices for the retrothyroid subgroup were sensitivity 86.7%, specificity 96.4%, positive predictive value 98.1%, negative predictive value 77.1%, and accuracy 89.8%. Accuracy indices for ectopic parathyroid adenomas were sensitivity 81.5%, specificity 100%, positive predictive value 100%, negative predictive value 92.4%, and accuracy 94.3%. For the overall group, SPECT/CT demonstrated a sensitivity of 85.1% and a PPV of 98.7%. SPECT/CT correctly identified the abnormal parathyroid gland in 60% of patients with a normal serum PTH (<6.9 pmol/L), 73% between 6.9-9.9 pmol/L, 86% between 10.0-14.9 pmol/L, 100% between 15.0-19.9 pmol/L, 88% between 20.0-24.5 pmol/L, and 100% of patients with a PTH greater than 25.0 pmol/L.

CONCLUSIONS

Dual-phase (99m)Tc- MIBI with SPECT/CT is an accurate and reliable means to correctly localize both retrothyroid and ectopic parathyroid adenomas for the purpose of surgical planning. The accuracy of SPECT/CT increases with increasing serum PTH levels.

Clinical Utility of SPECT/CT Imaging Post-Radioiodine Therapy: Does It Enhance Patient Management in Thyroid Cancer?

BACKGROUND

The aim of this study was to evaluate post-therapy iodine-131 single-photon emission computed tomography/computed tomography ((131)I-SPECT/CT) imaging in comparison to conventional planar (131)I whole-body imaging, and to assess its clinical impact on the management of patients.

METHODS

We retrospectively reviewed planar (131)I whole-body and (131)I-SPECT/CT imaging findings in 67 patients who underwent (131)I therapy for thyroid cancer. Two nuclear medicine physicians reviewed the scans independently. The foci of increased tracer uptake were identified in the neck, thorax and elsewhere. Within the neck, the foci of (131)I-increased uptake were graded qualitatively as probable or definite uptake in thyroid remnants and probable or definite uptake in the lymph nodes. Serum thyroglobulin level, histopathology and other imaging findings served as the reference standard.

RESULTS

Of the 67 patients, 57 (85%) had radioiodine avid disease and 10 (15%) demonstrated non-radioiodine avid disease. Overall, post-therapy (131)I-SPECT/CT downstaged lymph node staging in 10 patients and upstaged it in 4 patients. This translated into a change of management for 9/57 (16%) patients with radioiodine avid disease. A change of management was observed in 5/10 patients with non-radioiodine avid disease confirmed in the post-(131)I-SPECT/CT study. Additionally, clinically significant findings such as incidental lung cancer, symptomatic pleural effusion and consolidation were also diagnosed in both groups of patients.

CONCLUSION

In patients with thyroid cancer, (131)I-SPECT/CT is a valuable addition to standard post-therapy planar imaging. SPECT/CT also improved diagnostic confidence and provided crucial clinical information leading to change of management for a significant number of these patients.

Hybrid Single-Photon Emission Computed Tomography/Computed Tomography Imaging Features of Tumoral Calcinosis in Technetium-99m Methylene Diphosphonate Bone Scintigraphy

Tumoral calcinosis (TC) is an uncommon ectopic calcification syndrome. TC is a benign condition characterized by the presence of large calcific soft tissue deposits occurring predominantly in a periarticular location. It generally occurs as a complication of renal dialysis or trauma, and is rarely seen in familial and sporadic cases. Bone scintigraphy is a sensitive method for diagnosing TC. We report a case of year old female with. She underwent bone scintigraphy to see the sites of involvement, which showed intense foci of tracer activity in soft tissue in bilateral thigh and gluteal region. Hybrid single-photon emission computed tomography/computed tomography of the pelvis and thigh localized tracer uptake to the calcification in the gluteal and thigh region.

Recurrent malignant pheochromocytoma with unusual omental metastasis: (68)Ga-DOTANOC PET/CT and (131)I-MIBG SPECT/CT scintigraphy findings

Pheochromocytomas are rare catecholamine-secreting tumors derived from the sympathetic nervous system. The most common sites of metastasis for pheochromocytoma or extra-adrenal paraganglioma are lymph nodes, bones, lungs, and liver. Patients with known or suspected malignancy should undergo staging with computed tomography (CT) or magnetic resonance imaging as well as functional imaging (e.g. with (123)I/(131)I-MIBG ((131)I-metaiodobenzylguanidine) and (68)Ga-DOTANOC ((68)Ga-labeled [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-1-NaI3-octreotide) positron emission tomography (PET)/CT) to determine the extent and location of disease. We present a case of recurrent malignant pheochromocytoma with unusual site of metastasis in omentum, which was positive on (68)Ga-DOTANOC PET/CT and (131)I-MIBG single-photon emission computed tomography (SPECT/)/CT scintigraphy.