Functional imaging in primary tumour-induced osteomalacia: relative performance of FDG PET/CT vs somatostatin receptor-based functional scans: a series of nine patients.

CONTEXT: Localization of phosphatonin-producing mesenchymal tumours in patients with primary tumour-induced osteomalacia (pTIO) is challenging. Functional imaging plays an important role in the localization of these tumours. OBJECTIVE: We studied the relative performance of different functional imaging modalities ((18) F-FDG PET/CT, (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT) in tumour localization in cases of pTIO. DESIGN AND METHODS: Retrospective chart evaluation of 16 patients with confirmed TIO treated from 2006 to 2013 was conducted in a tertiary care referral centre. RESULTS: Of 16, nine patients had pTIO. In these nine, the positivity rates of different functional imaging modalities were 50% for (18) F-FDG PET/CT (four of eight patients), 100% for (99) Tc-HYNIC-TOC SPECT/CT (six of six patients) and 100% for (68) Ga-DOTATATE PET/CT (seven of seven patients). Of nine patients, six were subjected to both the (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT and all of them showed coregistration on the two scans. CONCLUSIONS: In patients with pTIO, the somatostatin receptor-based functional scans performed better than (18) F-FDG PET/CT in tumour localization. Amongst the somatostatin receptor-based scans, (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT performed equally well for localization of tumours.

Tumor Thrombus within the Superior Sagittal Sinus Detected on FDG PET Venography.

Early detection of cereberal venous sinus thrombosis is important to prevent complication. Here we present an interstecting case of tumor thrombsosis of the superior sagittal venous sinus in a follow up case of adenocarcinoma esophagus, highlighting the feasibility for FDG PET venography for detection of the same.

Malignant Portal Vein Thrombosis with No Obvious Liver Parenchymal Mass on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

The presence of portal vein thrombosis (PVTT) in hepatocellular carcinoma (HCC) is associated with adverse prognosis with dismal survival. Malignant portal vein thrombosis usually develops as a contiguous extension of the liver tumour into portal vein or its branches. Here we present an interesting FDG PET-CT image of a patient with chronic hepatitis B infection having isolated malignant portal vein thrombosis without any obvious liver mass.

18 F-Fluorocholine PET-CT Outshines Sestamibi Scintigraphy in Detecting Parathyroid Adenomas in the Background of Hashimoto's Thyroiditis.

Ultrasonography neck and dual-phase 99m Tc-sestamibi (MIBI) scan are standard imaging techniques for the detection of parathyroid adenomas in primary hyperparathyroidism. However, in presence of coexistent thyroid disease or small size of adenomas, the accuracy of these imaging modalities is low and leads to delayed diagnosis. We here present a report of two patients with primary hyperparathyroidism and with a nondiagnostic MIBI scan, who subsequently underwent successful surgery after positive localization of adenomas on 18 F-fluorocholine positron emission tomography-computed tomography.

Prediction of Sentinel Lymph Node Biopsy Status in Breast Cancers with PET/CT Negative Axilla.

Background and Aim Prior knowledge of axillary node status can spare a lot of patients with early breast cancer morbidity due to an unnecessary axillary dissection. Our study compared various metabolic and pathological features that can predict the sentinel lymph node biopsy (SLNB) status in patients with positron emission tomography/computed tomography (PET/CT) negative axilla. Patients and Methods All consecutive patients with early breast cancers (< 5 cm) with PET/CT negative axilla who underwent breast surgery and SLNB from November 2016 to February 2020 were included. Various primary tumor (PT) pathological variables and metabolic variables on PET/CT such as maximum standardized uptake value (PT-SUV max ), metabolic tumor volume (PT-MTV), and total lesion glycolysis (PT-TLG) were compared using univariate and multivariate analyses for prediction of SLNB status. Results Overall 70 patients, all female, with mean age 55.6 years (range: 33-77) and mean tumor size 2.2 cm (range: 0.7-4.5), were included. SLNB was positive in 20% of patients ( n = 14) with nonsentinel nodes positive in 4% ( n = 3) patients. Comparing SLNB positive and negative groups, univariate analysis showed significant association of SLNB with low tumor grade, positive lymphovascular invasion (LVI), positive estrogen receptor (ER) status with lower mean K i -67 index (34.41 vs. 52.02%; p = 0.02), PT-SUV max (5.40 vs. 8.68; p = 0.036), PT-MTV (4.71 cc vs. 7.46 cc; p = 0.05), and PT-TLG (15.12 g/mL.cc vs. 37.10 g/mL.cc; p = 0.006). On multivariate analysis, only LVI status was a significant independent predictor of SLNB status (odds ratio = 6.23; 95% confidence interval: 1.15-33.6; p = 0.033). Conclusion SLNB is positive in approximately 20% of early breast cancers with PET/CT negative axilla and SLNB status appears to be independent of PT size. SLNB+ PTs were more likely to be LVI+ and ER + ve, with lower grade/K i -67/metabolic activity (SUV max /MTV/TLG) compared with SLNB-ve tumors. Logistic regression analysis revealed LVI status as the only significant independent predictor of sentinel lymph node status.

Ortner's Syndrome Associated with Takayasu's Aortoarteritis Identified on Fluorodeoxyglucose Positron-Emission Tomography/Computed Tomography.

Cardiovocal syndrome or Ortner's syndrome is hoarseness voice due to left recurrent laryngeal nerve palsy secondary to nerve compression caused by enlarged cardiovascular structures in the mediastinum. We present here an interesting positron-emission tomography/computed tomography image of a patient suspected to have Takayasu's aortoarteritis and presenting with hoarseness of voice.

IgG4 Related Kidney Disease with Extra-Renal Involvement Demonstrated on FDG PET/CT.

Immunoglobulin G4 (IgG4)-related kidney disease is a relatively rare clinical entity and usually occurs as an extra-pancreatic manifestation of IgG4-related autoimmune pancreatitis. We describe here the imaging findings of a patient who presented with recurrent multiorgan IgG4-related disease, involving bilateral kidneys/ureters, proximal small bowel, and multiple abdominal and extra-abdominal lymph nodes.

SUVmax/ADC Ratio as a Molecular Imaging Biomarker for Diagnosis of Biopsy-Naïve Primary Prostate Cancer.

BACKGROUND: Gallium-68-prostate-specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) has recently been shown to be very high accuracy in biopsy-naïve prostate cancer (PCa) detection and can potentially improve the low specificity noted with diffusion-weighted magnetic resonance imaging (DW-MRI), especially in instances of prostate inflammation. We aimed to compare the diagnostic accuracy of DW-MRI and PSMA PET/CT using apparent diffusion coefficient (ADC) and maximum standardized uptake (SUVmax) values in the diagnosis of PCa. PATIENTS AND METHODS: A retrospective study comparing and analyzing the diagnostic accuracy of prebiopsy DW-MRI and 68Ga-PSMA PET/CTs done in patients with suspected PCa (raised prostate specific antigen [PSA] and/or positive digital rectal examination) from January 2019 to December 2020. The standard of reference was transrectal ultrasound-guided biopsies. RESULTS: Sixty-seven patients were included in the study, mean age: 70 years (range 49-84), mean PSA: 23.2 ng/ml (range 2.97-45.6). Biopsy was positive for PCa in 56% (n = 38) and negative in 43% (n = 29). Of the benign results, benign hyperplasia was noted in 75% (n = 22) and prostatitis in 25% (n = 7). Of the PCa, 55% (n = 21) of were high International Society of Urological Pathology (ISUP) grade (4-5) and 45% (n = 17) low/intermediate ISUP grade (1-3). Overall the sensitivity/specificity/Accuracy for prediction of PCa of MRI using prostate imaging and reporting data system version 2 criteria and PSMA PET/CT using PCa molecular imaging standardized evaluation criteria was 92.1%/65.5%/80.5% and 76.3%/96.5%/85.1% respectively. Mean apparent diffusion co-efficient (mean ADC) value of benign lesions and PCa was 1.135 × 10-3 mm2/s and 0.723 × 10-3 mm2/s, respectively (P = 0.00001). Mean SUVmax and ADC of benign and PCa lesions was 4.01 and 16.4 (P = 0.000246). Mean SUVmax/ADC ratio of benign and malignant lesions was 3.8 × 103 versus 25.21 × 103 (P < 0.000026). Inverse correlation was noted between ADC and SUVmax values (R = -0.609), inverse correlation noted between ADC and Gleason's score (R = -0.198), and positive correlation of SUVmax and SUVmax/ADC with Gleason's score (R = 0.438 and R = 0.448). Receiver operating characteristic curve analysis revealed a SUVmax cutoff 6.03 (sensitivity/specificity - 76%/90%, area under the curve (AUC) - 0.935, Youden index (YI) - 0.66), ADC cutoff of 0.817 × 10-3 mm2/s (sensitivity/specificity - 79%/86%, AUC - 0.890, YI - 0.65), and SUVmax/ADC ratio cutoff of 7.43 × 103 (sensitivity/specificity - 87%/98%, AUC - 0.966, YI - 0.85) for PCa diagnosis. CONCLUSION: For diagnosis of biopsy-naïve PCas, the combination of diffusion-weighted MRI and PSMA PET/CT (i.e., SUVmax/ADC ratio) shows better diagnostic accuracy than either used alone and the combination of PET and MRI is especially useful when distinguishing cancer from prostatitis.

Incidental Detection of Ischemic Myocardium on 68 Ga-FAPI PET/CT.

Recent studies using Ga-68-labeled fibroblast activation protein inhibitors (FAPI) PET have shown strong association between focal uptake of FAPI in myocardium and presence of coronary artery disease. We present an interesting case of a 76-year-old female with breast cancer with incidental uptake on FAPI PET in apex and septal wall of left ventricle myocardium correlating with findings of ischemia on dobutamine stress myocardial perfusion imaging and anatomical stenosis on coronary angiography.

Primary Retroperitoneal Transitional Cell Carcinoma Identified on 18F-Fludeoxyglucose Positron Emission Tomography/Computed Tomography: An Exceedingly Rare Radio-Pathological Entity.

We report here initial staging and follow-up imaging findings of a case of primary retroperitoneal transitional cell carcinoma, one of the rarest nonurological tumors of the retroperitoneal space, to highlight the importance of 18F-fludeoxyglucose positron emission tomography/computed tomography in this infrequently encountered pathology.

Anti-Leucine-Rich Glioma-Inactivated 1 Limbic Encephalitis with Normal Magnetic Resonance Imaging Detected on Fluordeoxygluose Positron Emission Tomography/Computed Tomography.

Leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis is an emerging autoimmune disorder with antibodies to the voltage-gated potassium channel complex. Here, we report clinico-imaging findings of a 77-year-old female presenting with acute-onset seizures, normal magnetic resonance imaging and with abnormal fluordeoxygluose positron-emission tomography-computed tomography and positive anti-LGI1 antibodies on immunofluroscence assay.

Complete Pathological Response Noted in Explanted Liver After Y90-SIR-Spheres Therapy for Hepatocellular Carcinoma.

In the treatment of hepatocellular carcinoma, achieving complete pathological response (CPR) in explanted liver specimens following any locoregional treatments is associated with reduced recurrence rates and better posttransplant survival compared to the incomplete response. Here, we present the imaging findings of a patient who achieved CPR in the explanted liver following Y-90 SIR-Spheres® therapy.

Evaluation of Diagnostic Accuracy and Impact of Preoperative Positron Emission Tomography/Computed Tomography in the Management of Early Operable Breast Cancers.

AIM: Our aim of this study was to evaluate the diagnostic accuracy of staging positron emission tomography/computed tomography (PET/CT) in early breast cancers (EBCs) and to assess its impact on disease management. PATIENTS AND METHODS: We retrospectively reviewed preoperative PET/CT scans of patients from January 2015 to December 2018 with Stage I/II, clinically T1-T2 N0-N1 breast cancers. The diagnostic performance of PET/CT for nodal (N) and distant metastases (M), its correlation with patient/tumor-specific factors, and its impact on disease management were analyzed using histopathology/clinical follow-up as standards of reference. RESULTS: Of 158 patients evaluated, 14% of patients were Stage I (T1N0), 60% were Stage IIA (T1N1, T2N0), and 26% were Stage IIB (T2N1). Sensitivity, specificity, and the diagnostic accuracy of PET/CT for axillary staging were 76%, 97%, and 84% and for distant metastasis evaluation were 100%, 98%, and 99%, respectively. The diagnostic accuracy of PET/CT for axillary staging was lower for low-grade, T1 tumors, postmenopausal group, and luminal A pathological subtype (77%, 84%, 81%, and 73%, respectively) compared to high-grade, T2 tumors, premenopausal group, and nonluminal A subtype (88%, 88%, 94%, and 87%, respectively). Distant metastases were detected on PET/CT in overall 16% (n = 25) of the patients (9% in Stage IIA and 27% in Stage IIB). PET/CT also incidentally identified clinically occult internal mammary nodes in 5% (n = 8) and organ-confined synchronous second malignancies in 5% (n = 8) of the patients. CONCLUSION: Preoperative PET/CT should be considered in all EBCs> 2 cm as it upstages the disease and alters management in about 24% of these patients. Given its high specificity for axillary staging PET/CT, patients with PET-positive axilla can be subjected to axillary dissection and those with PET-negative axilla to sentinel lymph node biopsy. The yield and diagnostic accuracy of PET/CT is less for low-grade tumors <2 cm and with luminal A subtype.

Diagnostic Accuracy of Prebiopsy Ga-68 PSMA PET/CT in Detecting Primary Prostate Carcinomas with Prostate-Specific Antigen <50 ng/ml.

BACKGROUND AND AIM: Serum prostate-specific-antigen (PSA) guided systematic transrectal ultrasound (TRUS)-guided biopsies are known to have a low predictive value in detection of primary prostate carcinomas (PCa). Our aim was to evaluate the accuracy of gallium-68 (Ga-68) prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) for the detection of PCa with serum PSA <50 ng/ml. PATIENTS AND METHODS: We retrospective analyzed prebiopsy Ga-68 PSMA PET/CT's of all patients with suspected PCa from October 2019 to March 2020. Several quantitative clinical and PET/CT variables were compared in benign and malignant groups and assessed for significance using an independent t-test. Diagnostic performance of PSMA PET/CT for detection of cancer was evaluated and compared with the diagnostic performance of cancer risk predicting calculator (European Randomized Study for Screening of Prostate Cancer [ERSPC3]). The standard of reference was 12-core TRUS-guided biopsies. RESULTS: Sixty-four patients were included with mean age 70 years (range 48-94 years); mean PSA 15.67 ng/ml (range 1.74-44), mean PSA density 0.32 ng/ml2 (range 0.01-0.99) and mean prostate volume 54.55 cc (range 16.5-182). 64% (n = 41/64) patients had benign histology and 36% (n = 23/64) had carcinoma. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PSMA PET/CT for detecting PCa reported using the prostate cancer molecular imaging standardized evaluation (PROMISE) was 74%, 92%, 85%, 86%, and 86%, respectively. Mean prostate maximum standardized uptake value (SUVmax) was significantly higher in PCa versus Benign lesions (19.56 ± 18.11 vs. 4.21 ± 1.5, P = 0.00001), in patients with PSA >20 ng/ml versus PSA <20 ng/ml (19.1 ± 20.6 vs. 6.01 ± 5.4, P-0.0052), and in patients with Gleason's score (GS) score >7 versus GS ≤7 (28.1 ± 20.3 vs. 10.2 ± 8.9, P-0.010). SUVmax cutoff value of 5.6 on PSMA PET/CT showed a sensitivity of 95% and specificity of 90.9% (area under the curve 0.990, P < 0.0001). CONCLUSION: Ga-68 PSMA PET/CT can differentiate benign and malignant lesions of the prostate with very high accuracy and when used alongside with ERSPC3 calculator and magnetic resonance imaging, could potentially reduce painful and often unnecessary prostate biopsies.

Pancreatitis, Cholangitis, and Gastritis: The Triumvirate of Immunoglobulin G4-Related Disease Identified Simultaneously on 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Immunoglobulin G4-related disease (IgG4) is an immune-mediated fibro-inflammatory entity which affects multiple organs, most frequently the pancreas. Although extrapancreatic inflammations are commonly seen in 18F-fluorodeoxyglucose positron emission tomography/computed tomography of majority of these patients at follow-up, simultaneous involvement of the gastric/biliary tract at presentation is rare. Here, we present imaging findings of a patient who presented with obstructive jaundice and initially thought to be due to cholangiocarcinoma, but was subsequently diagnosed as an IgG4-related inflammation.

Hypermetabolic Diffuse Proximal Small Bowel Wall Thickening on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography? Consider Strongyloidiasis among the Differentials.

Strongyloidiasis is an emerging tropical/subtropical parasitic infection commonly encountered in immunocompromised patients and often accompanied by life-threatening gram-negative bacteremia. We presented an interesting image of a critically ill 66-year-old lady, an asthmatic on high dose steroids, presenting with unexplained fever and vomiting where fluorodeoxyglucose positron emission tomography/computed tomography and endoscopic biopsy revealed this often neglected pathogenic nematode.

A Rare Case of Sarcoidosis Presenting as Diffuse Contracturing Granulomatous Myositis on Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is an established imaging modality in diagnosis and treatment response monitoring of sarcoidosis. Multisystemic involvement of sarcoidosis is characteristically seen on PET/CT; however, isolated organ involvement is rare. We describe here a case of a 52-year-old male with generalized muscle weakness, an extremely rare clinical manifestation of sarcoidosis.

Role of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Various Orbital Malignancies.

Orbital swelling comprises wide spectrum of pseudotumors, benign and malignant tumor. Malignant tumor may be primary or secondary tumor, and they constitute about 36% of orbital tumors in adult. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan is extensively used in hematological malignancies and in solid tumors for staging, treatment response, and restaging. Recently, the use of FDG-PET/CT in orbital malignancies has gained importance. The aim of this pictorial essay is to illustrate few important orbital malignancies detected in F-18 FDG-PET/CT and discuss its role in assessing the primary lesion and associated systemic finding.

Type-2 diabetes related intermediate phenotypic traits in north Indian diabetics.

Asian Indians are known to be at a higher risk of developing T2DM, but the underlying genetic factor in this population is still not well understood. T2DM is a complex genetic trait and assessment of disease related intermediate phenotypic traits is an important initial step towards any systematic genomic study. Therefore, in the present study we have assessed diabetes related intermediate phenotypic traits of insulin secretion and insulin resistance in the patients belonging to this population. The study included 157 T2DM patients of either sex ranging in age from 45-80 years and 84 non-diabetic subjects with no family history of diabetes, ranging in age from 45 to 75 years served as controls. Intermediate phenotypic traits studied were BMI, W: H ratio, fasting free fatty acid level and Insulin resistance and secretion. Diabetics were found to have significantly higher W: H ratio (p<0.001), FFA (p<0.001) and HOMA-R (p<0.001) as compared to non-diabetics. However, there was no significant difference in their BMI and HOMA-ß. There was a positive correlation between FFA level and HOMA-R among diabetics, but not among controls. These findings suggest that in abdominal obesity FFA mediated insulin resistance is an important causative factor underlying T2DM in this population. Moreover, comparable HOMA-ß in diabetics reflects compensatory insulin hyper secretion in these subjects. There is a need to examine relative contribution and precise nature of genetic factor in their tendency for central obesity, free fatty acidemia and insulin resistance.