Thumb Metacarpal-Trapezoid Impingement as an Etiology of Pain After Trapeziectomy and Basal Joint Soft Tissue Arthroplasty: A Case Series.

PURPOSE: To report a poorly described etiology for pain after trapeziectomy and soft tissue basal joint arthroplasty, diagnosed with the aid of nuclear imaging. METHODS: Five patients (4 women and 1 man), average age 62 years (range, 59-65 years) presented with pain an average of 7 months (range, 2-11 months) after basal joint arthroplasty. The dominant hand was involved in all cases. Advanced imaging including 25 mCi 99mTc methylene diphosphonate bone scintigraphy and single-photon emission computed tomography (CT) showed intense tracer uptake between the base of the thumb metacarpal and residual trapezoid. Computed tomography scans confirmed abutment between these bones. The symptoms were attributed to this finding, and revision surgery consisting of excision of the trapezoid and arthrodesis of the index and middle finger carpometacarpal joints was performed. RESULTS: Mean follow-up was 40 months (range, 12-60 months). Grip strength improved from a mean of 10.5 to 23 kg, and lateral pinch strength improved from a mean of 3 to 6.75 kg. Radiographic fusion of the index finger metacarpal to capitate was confirmed in 4 of 5 patients; it was indeterminate in one patient who was completely pain-free. Radiographic fusion of long finger carpometacarpal joints was indeterminate in 3 patients. Patient-Rated Wrist Evaluation pain scores improved from 35 to 6, Patient-Rated Wrist Evaluation function scores from 78 to 14, and Quick-Disabilities of the Arm, Shoulder, and Hand scores from 37 to 18. CONCLUSIONS: Impingement between the base of the thumb metacarpal and remaining trapezoid should be considered a potential source of pain after trapeziectomy and soft tissue arthroplasty. Advanced imaging (bone scintigraphy and single-photon emission CT and standard CT) are helpful to confirm the diagnosis. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Advanced Nuclear Medicine and Molecular Imaging in the Diagnosis of Cardiomyopathy.

OBJECTIVE. The purpose of this article is to summarize the protocol, interpretation, and diagnostic performance of nuclear medicine and molecular imaging in imaging two distinctive, underdiagnosed cardiomyopathies: cardiac amyloidosis and cardiac sarcoidosis. CONCLUSION. Emerging new radiotracers and advanced molecular imaging modalities enable us to noninvasively characterize certain types of cardiomyopathies, including cardiac amyloidosis and cardiac sarcoidosis, with great confidence. We expect to improve recognition and promote the application of such advanced techniques in the imaging and management of these potentially lethal cardiomyopathies.

Pilot study: Evaluation of dual-energy computed tomography measurement strategies for positron emission tomography correlation in pancreatic adenocarcinoma.

We sought to determine whether dual-energy computed tomography (DECT) measurements correlate with positron emission tomography (PET) standardized uptake values (SUVs) in pancreatic adenocarcinoma, and to determine the optimal DECT imaging variables and modeling strategy to produce the highest correlation with maximum SUV (SUVmax). We reviewed 25 patients with unresectable pancreatic adenocarcinoma seen at Mayo Clinic, Scottsdale, Arizona, who had PET-computed tomography (PET/CT) and enhanced DECT performed the same week between March 25, 2010 and December 9, 2011. For each examination, DECT measurements were taken using one of three methods: (1) average values of three tumor regions of interest (ROIs) (method 1); (2) one ROI in the area of highest subjective DECT enhancement (method 2); and (3) one ROI in the area corresponding to PET SUVmax (method 3). There were 133 DECT variables using method 1, and 89 using the other methods. Univariate and multivariate analysis regression models were used to identify important correlations between DECT variables and PET SUVmax. Both R2 and adjusted R2 were calculated for the multivariate model to compensate for the increased number of predictors. The average SUVmax was 5 (range, 1.8-12.0). Multivariate analysis of DECT imaging variables outperformed univariate analysis (r = 0.91; R2 = 0.82; adjusted R2 = 0.75 vs. r < 0.58; adjusted R2 < 0.34). Method 3 had the highest correlation with PET SUVmax (R2 = 0.82), followed by method 1 (R2 = 0.79) and method 2 R2 = 0.57). DECT thus has clinical potential as a surrogate for, or as a complement to, PET in patients with pancreatic adenocarcinoma.

Role of lipoprotein(a) concentrations in bioprosthetic aortic valve degeneration.

OBJECTIVES: Lipoprotein(a) (Lp(a)) is associated with an increased incidence of native aortic stenosis, which shares similar pathological mechanisms with bioprosthetic aortic valve (bAV) degeneration. However, evidence regarding the role of Lp(a) concentrations in bAV degeneration is lacking. This study aims to evaluate the association between Lp(a) concentrations and bAV degeneration. METHODS: In this retrospective multicentre study, patients who underwent a bAV replacement between 1 January 2010 and 31 December 2020 and had a Lp(a) measurement were included. Echocardiography follow-up was performed to determine the presence of bioprosthetic valve degeneration, which was defined as an increase >10 mm Hg in mean gradient from baseline with concomitant decrease in effective orifice area and Doppler Velocity Index, or new moderate/severe prosthetic regurgitation. Levels of Lp(a) were compared between patients with and without degeneration and Cox regression analysis was performed to investigate the association between Lp(a) levels and bioprosthetic valve degeneration. RESULTS: In total, 210 cases were included (mean age 74.1±9.4 years, 72.4% males). Median time between baseline and follow-up echocardiography was 4.4 (IQR 3.7) years. Bioprostheses degeneration was observed in 33 (15.7%) patients at follow-up. Median serum levels of Lp(a) were significantly higher in patients affected by degeneration versus non-affected cases: 50.0 (IQR 72.0) vs 15.6 (IQR 48.6) mg/dL, p=0.002. In the regression analysis, high Lp(a) levels (≥30 mg/dL) were associated with degeneration both in a univariable analysis (HR 3.6, 95% CI 1.7 to 7.6, p=0.001) and multivariable analysis adjusted by other risk factors for bioprostheses degeneration (HR 4.4, 95% CI 1.9 to 10.4, p=0.001). CONCLUSIONS: High serum Lp(a) is associated with bAV degeneration. Prospective studies are needed to confirm these findings and to investigate whether lowering Lp(a) levels could slow bioprostheses degradation.

Opportunistic screening for coronary artery calcium deposition using chest radiographs - a multi-objective models with multi-modal data fusion.

Background: To create an opportunistic screening strategy by multitask deep learning methods to stratify prediction for coronary artery calcium (CAC) and associated cardiovascular risk with frontal chest x-rays (CXR) and minimal data from electronic health records (EHR). Methods: In this retrospective study, 2,121 patients with available computed tomography (CT) scans and corresponding CXR images were collected internally (Mayo Enterprise) with calculated CAC scores binned into 3 categories (0, 1-99, and 100+) as ground truths for model training. Results from the internal training were tested on multiple external datasets (domestic (EUH) and foreign (VGHTPE)) with significant racial and ethnic differences and classification performance was compared. Findings: Classification performance between 0, 1-99, and 100+ CAC scores performed moderately on both the internal test and external datasets, reaching average f1-score of 0.66 for Mayo, 0.62 for EUH and 0.61 for VGHTPE. For the clinically relevant binary task of 0 vs 400+ CAC classification, the performance of our model on the internal test and external datasets reached an average AUCROC of 0.84. Interpretation: The fusion model trained on CXR performed better (0.84 average AUROC on internal and external dataset) than existing state-of-the-art models on predicting CAC scores only on internal (0.73 AUROC), with robust performance on external datasets. Thus, our proposed model may be used as a robust, first-pass opportunistic screening method for cardiovascular risk from regular chest radiographs. For community use, trained model and the inference code can be downloaded with an academic open-source license from https://github.com/jeong-jasonji/MTL_CAC_classification . Funding: The study was partially supported by National Institute of Health 1R01HL155410-01A1 award.

Identification of Acute Mesenteric Ischemia on 18F-FDG PET/CT.

ABSTRACT: Acute mesenteric ischemia resulting in bowel necrosis is a surgical emergency. First identification of acute mesenteric ischemia with FDG PET/CT is uncommon, because patients with bowel ischemia are usually diagnosed by other imaging methods such as CT. Nevertheless, prompt imager recognition of the PET/CT findings of mesenteric ischemia and necrosis is critical for proper triage of the patient to potentially lifesaving interventions. We present a 39-year-old woman with portal vein thrombosis who was sent for 18F-FDG PET/CT evaluation of a suspected pancreatic head neoplasm but was unexpectedly found to have ischemic and necrotic small bowel secondary to mesenteric venous infarction.

Diagnosis of Primary Scrotal Lymphedema Using 99mTc-Sulfur Colloid Lymphoscintigram: Correlation With MR Lymphangiogram.

ABSTRACT: We report a case of a 19-year-old man who presented with severe scrotal swelling. His medical history was notable for severe global edema at birth. Most areas of swelling had resolved by adolescence with exception of the scrotum and the left lower extremity. 99mTc-filtered sulfur colloid lymphoscintigraphy of the lower extremities demonstrated prominent dermal backflow into the superficial scrotum and thighs, which were confirmed on the SPECT/CT images, and correlated with findings on MR lymphangiogram. Lymphoscintigram and MR lymphangiogram may provide complementary information to aid diagnosis and management of primary scrotal lymphedema.

Can lymphatic drainage of head and neck melanoma be predicted?

BACKGROUND: The lymphatic drainage patterns of the head and neck (H&N) is complex. Therefore, identification of the sentinel lymph node (SLN) for H&N melanoma can be challenging. METHODS: Retrospective review of a prospectively collected melanoma database, from February 1997 through October 2008, identified 137 patients with H&N melanoma. All underwent pre-operative lymphoscintigraphy, and after 2007, patients underwent single photon emission computed tomography combined with computed tomography (SPECT/CT). RESULTS: The mean number of SLNs per patient was 2.6. An SLN was successfully identified in 97% of patients, and in 9%, the SLN was positive for metastatic disease. The majority of patients (88%) drained to a unilateral level. Bilateral drainage occurred in 10%, with only two patients draining outside of the neck. The majority of patients (58%) had an SLN in level IIa (jugulodigastric lymph nodes). The regional recurrence rate was 4%, which all occurred prior to the use of SPECT/CT. DISCUSSION: Utilization of SPECT/CT and knowledge of common lymphatic drainage patterns in neck lymph node levels can assist the surgeon in properly locating and excising the SLN with minimal morbidity, limiting unnecessary dissections, as well as reducing false negative results.

Nuclear Medicine and Molecular Imaging in Nodal Staging and Surveillance of Ocular Melanoma: Case Reports and Review of the Literature.

Ocular melanoma (OM) is a rare noncutaneous malignancy and consists of 2 different subtypes based on the anatomic location in the eye: uveal melanoma and conjunctival melanoma. Like cutaneous melanoma, OM benefits from nuclear medicine and molecular imaging in nodal staging and clinical management. Through the illustration of 2 distinctive cases, we aim to demonstrate the complementary roles of standard lymphoscintigraphy, advanced SPECT/CT, 18F-FDG PET/CT, and 18F-FDG PET/MRI in accurate nodal staging and surveillance of OM. We also review the epidemiology, existing staging guidelines, and management of uveal melanoma and conjunctival melanoma.

Nodular Fat-Sparing Hepatic Parenchyma as 11C-Choline-Avid Finding on PET/CT.

Focal nodular fat sparing of the liver may show, on PET/CT imaging, prominent tracer uptake over a background of less metabolic features of steatosis. This finding, already reported with F-FDG, may mimic primary or secondary neoplasms of the liver. The authors present an additional case of nodular fat-sparing hepatic parenchyma exhibiting C-choline avidity during PET/CT assessment for biochemical recurrence of prostate cancer.

Utility of subtraction ictal SPECT when video-EEG fails to distinguish atypical psychogenic and epileptic seizures.

This study was designed to evaluate the utility of subtraction ictal SPECT coregistered to MRI (SISCOM) in atypical psychogenic nonepileptic seizures (PNES). Video-EEG monitoring (vEEG) is the gold standard for PNES diagnosis but, like any modality, has limitations. In difficult cases in which the diagnosis is suspected but remains in question after vEEG, a complementary study that could help differentiate epilepsy from PNES would be desirable. Thirteen SISCOM studies performed in patients with a final diagnosis of PNES were retrospectively reviewed. Common indications for SISCOM were semiology consistent with partial epilepsy (9/13), abnormal head MRI (5/13), and reported abnormal routine EEG (5/13). SISCOM was negative in 85% (11/13) of patients and was helpful in increasing the diagnostic certainty of PNES in these exceptional cases.

"Migratory" Pattern of Corticosteroid-Related Multifocal Bone Infarction on Bone Scintigraphy.

We present serial bone scintigraphy examinations in a 38-year-old woman who presented with posterior left rib pain in the setting of adrenal insufficiency secondary to pituitary damage as a result of radiation treatment for orbital sarcoma.

Molecular Imaging in Diagnosis of Tumor-induced Osteomalacia.

Tumor induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by overproduction of fibroblast growth factor 23 (FGF23) secreted by benign mesenchymal neoplasm. Due to its nonspecific clinical presentation or lack of awareness, the diagnosis of TIO is often significantly delayed resulting in patients' prolonged physical suffering or psychological distress. Successful detection or complete surgical resection of the causative tumor typically leads to rapid resolution of symptoms or reversal of biochemical imbalance. Nuclear medicine and molecular imaging have been playing a promising role as the first-line imaging modalities in the diagnosis and localization of occult FGF23 secreting mesenchymal tumor, especially with the emerging whole-body, head-to-toe Ga68-DOTATATE PET/CT technique. Combined focused diagnostic CT and/or MRI are imperative for accurate delineation of tumor and surgical guidance.

Applications of SPECT/CT in nuclear radiology.

OBJECTIVE: The purpose of this pictorial essay is to illustrate several clinical situations in which SPECT/CT can be effectively applied in nuclear radiology practice. CONCLUSION: SPECT/CT has recently emerged as a valuable adjunct to standard techniques in clinical nuclear radiology. This technique provides significantly improved scintigraphic localization and characterization of disease, increasingly important in this era of minimally invasive surgery and targeted radiotherapy.

A multi-site validation trial of radioactive seed localization as an alternative to wire localization.

This study aims to validate radioactive seed localization (RSL) as an alternative to wire localization (WL) in the operative excision of nonpalpable breast lesions. Eligible patients were recruited sequentially. A sample of 99 patients treated with WL was compared to the next 383 patients treated with RSL. Margins were considered "negative" if > or =2 mm from in-situ and invasive disease. Pain and convenience scores were recorded on a 10-point scale. Patient characteristics and histology were similar. The lesion and localization device were retrieved in all patients. Margins of the first specimen were negative in 73% of RSL patients, versus 54% of WL patients (p < 0.001). A second operation was required in 8% of RSL patients to achieve negative margins, versus 25% of WL patients (p < 0.001). Pain scores were not statistically different. However, the RSL group had higher convenience scores (p = 0.015). RSL is safe, effective, and compared to WL, reduces the rates of intraoperative re-excision and reoperation for positive margins by 68%. Patient satisfaction is improved with RSL. We strongly favor RSL over WL.

Endotracheal metastasis from squamous cell cancer of the head and neck: PET/CT imaging.

Lung cancer is the main malignancy with frequent endotracheal and endobronchial dissemination. Extrapulmonary sources of airway metastasis are less common, predominantly seen with breast, colorectal, and renal neoplasms. Head and neck cancer represents only a small fraction of tumors with tracheal luminal metastasis. We present 2 such rare cases with F-18 FDG PET/CT imaging. These 2 companion cases show in one instance an obvious hypermetabolic endotracheal lesion and in the other one a discrete airway metastasis overlooked by chest CT and diagnosed by PET with coregistered CT.

99mTc-Sulfur Colloid Bone Marrow Scintigraphy in Diagnosis of Diffuse Pulmonary Extramedullary Hematopoiesis Secondary to Myelofibrosis.

Our objective was to define the role of combined 99mTc-sulfur colloid bone marrow (SC BM) scintigraphy, SPECT or SPECT/CT, and chest CT in diagnosing diffuse pulmonary extramedullary hematopoiesis (PEMH) in patients with myelofibrosis. Methods: We retrospectively reviewed 99mTc-SC BM scintigraphy scans performed at our institution for the diagnosis of diffuse PEMH, as well as accompanying chest CT and SPECT/CT imaging findings. Relevant clinical information, including respiratory manifestations, pulmonary hypertension, and subjective response to whole-lung radiation therapy, was also summarized. Results: Twenty-two myelofibrosis patients with 27 99mTc-SC BM scintigraphy scans were diagnosed with diffuse PEMH. In 21 patients (95%) with accompanying chest CT and SPECT/CT scans, the most common CT findings were ground-glass opacity, interstitial infiltration, and pleural effusion. Of 20 patients (91%) who underwent 2-dimensional echocardiography studies, 12 (55%) were diagnosed with pulmonary hypertension. All 12 patients exhibited the aforementioned nonspecific CT imaging findings, with 8 (66%) of them presenting with respiratory symptoms, including dyspnea, shortness of breath, and cough. In the remaining 8 patients, without pulmonary hypertension, half had similar respiratory symptoms. Fourteen patients (64%) of this cohort received whole-lung radiation therapy, of whom 7 (50%) experienced symptom relief after therapy. Conclusion: Nonspecific respiratory symptoms should raise concern about pulmonary hypertension and diffuse PEMH in patients with advanced-stage myelofibrosis. Combined 99mTc-SC BM scintigraphy and SPECT/CT is a promising noninvasive imaging tool to diagnose this rare clinical entity.Key Words: hematology; respiratory; SPECT/CT; pulmonary hematopoiesis; Tc-99m sulfur colloid scintigraphy; myelofibrosis.

Postlaparoscopic abdominal port-site metastasis: F-18 FDG PET/CT demonstration.

Laparoscopic surgery has expanded its applications to treatment of malignant neoplasms with lower morbidity and mortality compared with the ones carried by conventional procedures. With the increasing volume of this minimally invasive technique, complications such as port-site tumor seeding may have a higher occurrence. Abdominal wall metastasis has been reported with conventional cross-sectional imaging. The authors present 2 cases of early detection of port-site tumor implantation by PET/CT.