Search

Purpose: The metabolically most active lesion in 2-deoxy-2-(\(^{18}\)F)fluoro-D-glucose (\(^{18}\)F-FDG) PET/CT can predict progression-free survival (PFS) in patients with medullary thyroid carcinoma (MTC) starting treatment with the tyrosine kinase inhibitor (TKI) vandetanib. However, this metric failed in overall survival (OS) prediction. In the present proof of concept study, we aimed to explore the prognostic value of intratumoral textural features (TF) as well as volumetric parameters (total lesion glycolysis, TLG) derived by pre-therapeutic \(^{18}\)F-FDG PET. Methods: Eighteen patients with progressive MTC underwent baseline \(^{18}\)F-FDG PET/CT prior to and 3 months after vandetanib initiation. By manual segmentation of the tumor burden at baseline and follow-up PET, intratumoral TF and TLG were computed. The ability of TLG, imaging-based TF, and clinical parameters (including age, tumor marker doubling times, prior therapies and RET (rearranged during transfection) mutational status) for prediction of both PFS and OS were evaluated. Results: The TF Complexity and the volumetric parameter TLG obtained at baseline prior to TKI initiation successfully differentiated between low- and high-risk patients. Complexity allocated 10/18 patients to the high-risk group with an OS of 3.3y (vs. low-risk group, OS=5.3y, 8/18, AUC=0.78, P=0.03). Baseline TLG designated 11/18 patients to the high-risk group (OS=3.5y vs. low-risk group, OS=5y, 7/18, AUC=0.83, P=0.005). The Hazard Ratio for cancer-related death was 6.1 for Complexity (TLG, 9.5). Among investigated clinical parameters, the age at initiation of TKI treatment reached significance for PFS prediction (P=0.02, OS, n.s.). Conclusions: The TF Complexity and the volumetric parameter TLG are both independent parameters for OS prediction.

PURPOSE: We aimed to (a) elucidate the concordance of visual assessment of an initial I-ioflupane scan by a human interpreter with comparison to results using a fully automatic semiquantitative method and (b) to assess the accuracy compared to follow-up (f/u) diagnosis established by movement disorder specialists. METHODS: An initial I-ioflupane scan was performed in 382 patients with clinically uncertain Parkinsonian syndrome. An experienced reader performed a visual evaluation of all scans independently. The findings of the visual read were compared with semiquantitative evaluation. In addition, available f/u clinical diagnosis (serving as a reference standard) was compared with results of the human read and the software. RESULTS: When comparing the semiquantitative method with the visual assessment, discordance could be found in 25 (6.5%) of 382 of the cases for the experienced reader (ĸ = 0.868). The human observer indicated region of interest misalignment as the main reason for discordance. With neurology f/u serving as reference, the results of the reader revealed a slightly higher accuracy rate (87.7%, ĸ = 0.75) compared to semiquantification (86.2%, ĸ = 0.719, P < 0.001, respectively). No significant difference in the diagnostic performance of the visual read versus software-based assessment was found. CONCLUSIONS: In comparison with a fully automatic semiquantitative method in I-ioflupane interpretation, human assessment obtained an almost perfect agreement rate. However, compared to clinical established diagnosis serving as a reference, visual read seemed to be slightly more accurate as a solely software-based quantitative assessment.

The heart failure epidemic continues to rise with coronary artery disease as one of its main causes. Novel concepts for risk stratification to guide the referring cardiologist towards revascularization procedures are of significant value. Myocardial perfusion imaging using single-photon emission computed tomography (SPECT) agents has demonstrated high accuracy for the detection of clinically relevant stenoses. With positron emission tomography (PET) becoming more widely available, mainly due to its diagnostic performance in oncology, perfusion imaging with that modality is more practical than in the past and overcomes existing limitations of SPECT MPI. Advantages of PET include more reliable quantification of absolute myocardial blood flow, the routine use of computed tomography for attenuation correction, a higher spatiotemporal resolution and a higher count sensitivity. Current PET radiotracers such as rubidium-82 (half-life, 76 s), oxygen-15 water (2 min) or nitrogen-13 ammonia (10 min) are labeled with radionuclides with very short half-lives, necessitating that stress imaging is performed under pharmacological vasodilator stress instead of exercise testing. However, with the introduction of novel 18F-labeled MPI PET radiotracers (half-life, 110 min), the intrinsic advantages of PET can be combined with exercise testing. Additional advantages of those radiotracers include, but are not limited to: potentially improved cost-effectiveness due to the use of pre-existing delivery systems and superior imaging qualities, mainly due to the shortest positron range among available PET MPI probes. In the present review, widely used PET MPI radiotracers will be reviewed and potential novel 18F-labeled perfusion radiotracers will be discussed. Electronic supplementary material The online version of this article (10.1007/s10554-018-1469-z) contains supplementary material, which is available to authorized users.

Background Prostate-specific membrane antigen (PSMA)-directed radioligand therapy (RLT) is a promising yet not curative approach in castration-resistant (CR) prostate cancer (PC). Rational combination therapies may improve treatment efficacy. Here, we explored the effect of androgen receptor blockade (ARB) on PSMA expression visualized by PET and its potential additive effect when combined with 177Lu-PSMA RLT in a mouse model of prostate cancer. Methods Mice bearing human CRPC (C4-2 cells) xenografts were treated with 10 mg/kg enzalutamide (ENZ), with 50 mg/kg bicalutamide (BIC), or vehicle (control) for 21 days. PSMA expression was evaluated by 68Ga-PSMA11 PET/CT and quantified by flow cytometry of tumor fine needle aspirations before treatment and on days 23, 29, 34, and 39 post-therapy induction. For the RLT combination approach, mice bearing C4-2 tumors were treated with 10 mg/kg ENZ or vehicle for 21 days before receiving either 15 MBq (84 GBq/μmol) 177Lu-PSMA617 or vehicle. DNA damage was assessed as phospho-γH2A.X foci in tumor biopsies. Reduction of tumor volume on CT and survival were used as study endpoints. Results Tumor growth was delayed by ARB while 68Ga-PSMA11 uptake increased up to 2.3-fold over time when compared to controls. ABR-induced upregulation of PSMA expression was confirmed by flow cytometry. Phospho-γH2A.X levels increased 1.8- and 3.4-fold at 48 h in response to single treatment ENZ or RLT and ENZ+RLT, respectively. Despite significantly greater DNA damage and persistent increase of PSMA expression at the time of RLT, no additional tumor growth retardation was observed in the ENZ+RLT group (vs. RLT only, p = 0.372 at day 81). Median survival did not improve significantly when ENZ was combined with RLT. Conclusion ARB-mediated increases in PSMA expression in PC xenografts were evident by 68Ga-PSMA11 PET imaging and flow cytometry. 177Lu-PSMA617 effectively decreased C4-2 tumor size. However, while pre-treatment with ARB increased DNA damage significantly, it did not result in synergistic effects when combined with RLT. Electronic supplementary material The online version of this article (10.1186/s13550-018-0451-z) contains supplementary material, which is available to authorized users.

The novel PET probe 2-deoxy-2-(18)F-fluoro-D-sorbitol ((18)F-FDS) has demonstrated favorable renal kinetics in animals. We aimed to elucidate its imaging properties in two human volunteers. (18)F-FDS was produced by a simple one-step reduction from (18)F-FDG. On dynamic renal PET, the cortex was delineated and activity gradually transited in the parenchyma, followed by radiotracer excretion. No adverse effects were reported. Given the higher spatiotemporal resolution of PET relative to conventional scintigraphy, (18)F-FDS PET offers a more thorough evaluation of human renal kinetics. Due to its simple production from (18)F-FDG, (18)F-FDS is virtually available at any PET facility with radiochemistry infrastructure.

Calcinosis universalis describes calcific depositions in the skin and soft tissues and can occur in association with connective tissue diseases1,2. The calcifications are thought to be dystrophic, which assumes calcium deposition on the basis of tissue damage. While deposits can be visible on radiographs2, computed tomography (CT) may be helpful for the identification of involved tissue layers, monitoring of progression in patients with a large extent of calcium deposits, and evaluation of complications. A 68-year-old woman with a …

See the associated article on page [789][1]. The well-recognized limitations of conventional imaging with CT, MRI, and 99mTc-methylene diphosphonate bone scans have contributed to a revolution in PET imaging of prostate cancer (PCa). A plethora of PET radiotracers has entered preclinical and early

The original version of this article unfortunately contained a mistake. The middle name of the author Steven B. Rowe is incorrect. The corrected name is Steven P. Rowe.

The ability to create 3-dimensional (3D) renderings from multidetector computed tomography data enables a global overview of complex anatomy and disease processes which can be difficult to appreciate on 2-dimensional images. As such, 3D computed tomography has become an invaluable adjunct for diagnosis and treatment planning of many urologic conditions. A newly available method of 3D visualization, known as cinematic rendering, uses a complex lighting model to create photorealistic images and holds promise for improved discrimination of tumors and cancer staging in genitourinary imaging. Here, we present the first published case of a clear cell renal cell carcinoma visualized with cinematic rendering.

We developed a new scaffold for radionuclide-based imaging and therapy of clear cell renal cell carcinoma (ccRCC) targeting carbonic anhydrase IX (CAIX). Compound XYIMSR-01, a DOTA-conjugated, bivalent, low-molecular-weight ligand, has two moieties that target two separate sites on CAIX, imparting high affinity. We synthesized [111In]XYIMSR-01 in 73.8–75.8% (n = 3) yield with specific radioactivities ranging from 118 – 1,021 GBq/μmol (3,200–27,600 Ci/mmol). Single photon emission computed tomography of [111In]XYIMSR-01 in immunocompromised mice bearing CAIX-expressing SK-RC-52 tumors revealed radiotracer uptake in tumor as early as 1 h post-injection. Biodistribution studies demonstrated 26% injected dose per gram of radioactivity within tumor at 1 h. Tumor-to-blood, muscle and kidney ratios were 178.1 ± 145.4, 68.4 ± 29.0 and 1.7 ± 1.2, respectively, at 24 h post-injection. Retention of radioactivity was exclusively observed in tumors by 48 h, the latest time point evaluated. The dual targeting strategy to engage CAIX enabled specific detection of ccRCC in this xenograft model, with pharmacokinetics surpassing those of previously described radionuclide-based probes against CAIX.

Molecular imaging with positron emission tomography (PET) provides a powerful means of identifying and characterizing cancerous processes, as well as providing a quantitative framework within which response to therapy can be ascertained. Unfortunately, the most commonly used PET radiotracer, ¹⁸F-fluorodeoxyglucose (FDG), has not demonstrated a definitive role in determining response to therapy in metastatic renal cell carcinoma (RCC). As a result, new radiotracers able to reliably image RCC could be of tremendous value for this purpose.Five patients with known metastatic RCC were imaged with the low-molecular weight radiotracer ¹⁸F-DCFPyL, an inhibitor of the prostate-specific membrane antigen at 60 min post injection. ¹⁸F-DCFPyL PET/CT and conventional images (either contrast-enhanced computed tomography or magnetic resonance imaging) were centrally reviewed for suspected sites of disease.In all five patients imaged, sites of putative metastatic disease were readily identifiable by abnormal ¹⁸F-DCFPyL uptake, with overall more lesions detected than on conventional imaging. These PET-detected sites included lymph nodes, pancreatic parenchymal lesions, lung parenchymal lesions, a brain parenchymal lesion, and other soft tissue sites. ¹⁸F-DCFPyL uptake ranged from subtle to intense with maximum standardized uptake values (SUVmax) for the identified lesions of 1.6-19.3. Based upon this small patient series, limited pathology and imaging follow-up of these patients suggests a higher sensitivity for ¹⁸F-DCFPyL compared to conventional imaging in the detection of metastatic RCC (94.7 versus 78.9%).PSMA expression in the tumor neovasculature of RCC has been previously established and is believed to provide the basis for the imaging findings presented here. PSMA-based PET/CT with radiotracers such as ¹⁸F-DCFPyL may allow more accurate staging of patients with RCC and conceivably the ability to predict and follow therapy in patients treated with agents targeting the neovasculature.

We previously demonstrated the ability to detect metastatic prostate cancer using N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-4-18F-fluorobenzyl-l-cysteine (18F-DCFBC), a low-molecular-weight radiotracer that targets the prostate-specific membrane antigen (PSMA). PSMA has been shown to be associated with higher Gleason grade and more aggressive disease. An imaging biomarker able to detect clinically significant high-grade primary prostate cancer reliably would address an unmet clinical need by allowing for risk-adapted patient management. Methods: We enrolled 13 patients with primary prostate cancer who were imaged with 18F-DCFBC PET before scheduled prostatectomy, with 12 of these patients also undergoing pelvic prostate MR imaging. Prostate 18F-DCFBC PET was correlated with MR imaging and histologic and immunohistochemical analysis on a prostate-segment (12 regions) and dominant-lesion basis. There were no incidental extraprostatic findings on PET suggestive of metastatic disease. Results: MR imaging was more sensitive than 18F-DCFBC PET for detection of primary prostate cancer on a per-segment (sensitivities of up to 0.17 and 0.39 for PET and MR imaging, respectively) and per-dominant-lesion analysis (sensitivities of 0.46 and 0.92 for PET and MR imaging, respectively). However, 18F-DCFBC PET was more specific than MR imaging by per-segment analysis (specificities of 0.96 and 0.89 for PET and MR imaging for corresponding sensitivity, respectively) and specific for detection of high-grade lesions (Gleason 8 and 9) greater than 1.0 mL in size (4/4 of these patients positive by PET). 18F-DCFBC uptake in tumors was positively correlated with Gleason score (ρ = 0.64; PSMA expression, ρ = 0.47; and prostate-specific antigen, ρ = 0.52). There was significantly lower 18F-DCFBC uptake in benign prostatic hypertrophy than primary tumors (median maximum standardized uptake value, 2.2 vs. 3.5; P = 0.004). Conclusion: Although the sensitivity of 18F-DCFBC for primary prostate cancer was less than MR imaging, 18F-DCFBC PET was able to detect the more clinically significant high-grade and larger-volume tumors (Gleason score 8 and 9) with higher specificity than MR imaging. In particular, there was relatively low 18F-DCFBC PET uptake in benign prostatic hypertrophy lesions, compared with cancer in the prostate, which may allow for more specific detection of primary prostate cancer by 18F-DCFBC PET. This study demonstrates the utility of PSMA-based PET, which may be used in conjunction with MR imaging to identify clinically significant prostate cancer.

Prostate-specific membrane antigen (PSMA) is a recognized target for imaging prostate cancer. Here we present initial safety, biodistribution, and radiation dosimetry results with [(18)F]DCFPyL, a second-generation fluorine-18-labeled small-molecule PSMA inhibitor, in patients with prostate cancer.Biodistribution was evaluated using sequential positron-emission tomography (PET) scans in nine patients with prostate cancer. Time-activity curves from the most avid tumor foci were determined. The radiation dose to selected organs was estimated using OLINDA/EXM.No major radiotracer-specific adverse events were observed. Physiologic accumulation was observed in known sites of PSMA expression. Accumulation in putative sites of prostate cancer was observed (SUVmax up to100, and tumor-to-blood ratios up to50). The effective radiation dose from [(18)F]DCFPyL was 0.0139 mGy/MBq or 5 mGy (0.5 rem) from an injected dose of 370 MBq (10 mCi).[(18)F]DCFPyL is safe with biodistribution as expected, and its accumulation is high in presumed primary and metastatic foci. The radiation dose from [(18)F]DCFPyL is similar to that from other PET radiotracers.

Purpose The differentiation of oncocytoma from renal cell carcinoma (RCC) remains a challenge with currently available cross-sectional imaging techniques. As a result, a large number of patients harboring a benign oncocytoma undergo unnecessary surgical resection. In this study, we explored the utility of 99mTc-MIBI SPECT/CT for the differentiation of these tumors based on the hypothesis that the large number of mitochondria in oncocytomas would lead to increased 99mTc-MIBI uptake. Patients and Methods In total, 6 patients (3 with oncocytoma and 3 with RCC) were imaged with 99mTc-MIBI SPECT/CT. Relative quantification was performed by measuring tumor-to-normal renal parenchyma background ratios. Results All 3 oncocytomas demonstrated radiotracer uptake near or above the normal renal parenchymal uptake (range of uptake ratios, 0.85–1.78). In contrast, the 3 RCCs were profoundly photopenic relative to renal background (range of uptake ratios, 0.21–0.31). Conclusions 99mTc-MIBI SPECT/CT appears to be of value in scintigraphically distinguishing benign renal oncocytoma from RCC.

Metastatic disease to the small bowel is rare; however, it is important to recognize that when it does occurs a variety of complications are possible including obstruction, gastrointestinal bleeding, intussusception, and bowel perforation. We present here an unusual case of small bowel metastases in a patient with known metastatic liposarcoma in which the lesions manifested as rapidly evolving fat-density masses that necessitated segmental small bowel resection. Careful scrutiny of the small bowel in oncology patients is necessary to guide appropriate treatment and avoid potential catastrophic complications from small bowel metastases.

Rationale and Objectives An ever-expanding body of biological, genetic, and clinical evidence has brought to light the presence of the oligometastatic state of cancer, which is considered between localized disease and widespread metastases. Indeed, in some patients with oligometastatic disease, curative therapy is possible. Conclusions For select cancer histologies, aggressive focal therapy of oligometastatic lesions is already the clinical standard of care (i.e. colorectal cancer and sarcomas), while for other tumor types the evidence is still emerging (i.e. prostate, breast, etc.). It is increasingly important, therefore, for the radiologist interpreting oncology patients' staging or restaging examinations to be aware of those diseases for which targeted therapy of oligometastases may be undertaken to effectively guide such management. The improved imaging resolution provided by technological advances promise to aid in the detection of subtle sites of disease to ensure the identification of patients with oligometastases amenable to targeted treatment.

Renal cell carcinoma (RCC) is common with more than 60,000 new cases in the United States yearly. No curative therapies are available for metastatic RCC. Improved methods of imaging metastatic RCC would be of value in identifying sites of occult disease and potentially for judging response to therapy. A 58-year-old male with known metastatic clear cell RCC was imaged with both 18F-FDG and 18F-DCFPyL PET/CT. 18F-DCFPyL is a small molecule inhibitor of the prostate-specific membrane antigen (PSMA), a target known to be highly expressed on solid tumor neovasculature. Relative to 18F-FDG, 18F-DCFPyL identified more lesions and demonstrated higher tumor radiotracer uptake.

Technetium-99m (Single-photon emission computed tomography data were reconstructed using the clinical Flash 3D reconstruction and QSPECT methods. Two blinded readers then characterized each tumor as hot or cold. Semi-quantitative uptake ratios were calculated by dividing lesion activity by background renal activity for both Flash 3D and QSPECT reconstructions.The difference between median (mean) hot and cold tumor uptake ratios measured 0.655 (0.73) with the QSPECT method and 0.624 (0.67) with the conventional method, resulting in increased separation between hot and cold tumors. Sub-analysis of 7 lesions near the separation point showed a higher absolute difference (0.16) between QPSECT and Flash 3D mean uptake ratios compared to the remaining lesions.Our finding of improved separation between uptake ratios of hot and cold lesions using QSPECT reconstruction lays the foundation for additional quantitative SPECT techniques such as SPECT-UV in the setting of renal

Background Cinematic rendering (CR) a new method of 3D computed tomography (CT) volumetric visualization that produces photorealistic images. As with traditional 3D visualization methods, CR may prove to be of value in providing important information when evaluating regions of complex anatomy such as the heart. Methods The gated, IV contrast-enhanced chest CT angiogram data from three recent patients were evaluated with CR. Image comparision demonstrates the difference between CR and traditional volume rendering (VR), owing to a more complex lighting model that enhances surface detail and produces realistic shadows to add depth to 3D visualizations. Results Representative examples of normal cardiac anatomy, a coronary artery stenosis, and an intracardiac malignant neoplasm are presented with 2D multiplanar reconstruction, traditional VR and CR. A potential pitfall in CR utilization, namely the possibility of obscuring important pathology, is demonstrated and discussed. Conclusions CR is a promising method to enhance display volumetric CT data and should prove useful in diagnosis, treatment planning, surgical navigation, trainee education, and patient engagement. However, further study is needed to establish the advantaged and disadvantages of CR in comparison to other 3D methods.

A 28-year-old man with history of anaplastic oligodendroglimoma in the left frontal lobe presented with worsening right leg weakness 2 months after surgical resection. MRI of the brain and spine demonstrated a new mass in the left parietal lobe, as well as extraneural osseous metastases. FDG PET scan subsequently showed widespread extraneural metastatic disease. Extraneural metastases from primary brain tumors are a rare occurrence, although anaplastic oligodendroglioma has a propensity for spreading in such a manner. FDG PET can effectively stage patients with extraneural metastases from anaplastic oligodendroglioma by detecting metastatic disease in sites such as the skeleton and liver.

To explore the clinical utility of PSMA-targetedThree patients with metastatic urothelial carcinoma were imaged withThe relatively scant expression of PSMA by urothelial carcinoma likely limits the utility of PSMA-targeted PET imaging of this malignancy. Future research efforts should focus on the development of other molecularly targeted imaging agents for urothelial carcinoma.

Precise regional quantitative assessment of renal function is limited with conventional

99mTc-Sestamibi SPECT/CT imaging of renal cell carcinoma (RCC) has recently shown significant promise to distinguish benign oncocytomas from malignant RCC, where the former appears as high uptake in SPECT images and the latter as cold uptake. We aim towards radiomics analysis of cold uptake in SPECT images for another significant yet more daunting task of discriminating between RCC subtypes. The first step we pursue in the present work is feature selection by assessing the reproducibility of radiomic features. $^{99m}$Tc-estamibi SPECT/CT images of 50 patients with renal mass, plus a contrast-enhanced CT or MRI, were used by a trained radiologist to segment the region of interest (ROI) on the SPECT image. The impact of segmentation on reproducibility was studied by generating three ROIs via removing one voxel-layer from, or appending 1 and 2 voxel-layers to the manual ROIs $(ROI)_{0}$, ${ROI}_{-1}$, $ROI_{+1}$, $ROI_{+2}$). Images were then uniformly quantized with eight grey-levels (GL) (2$^{2}$-2$^{9}$). A total of 363 radiomic features, verified within the Image Biomarker Standardization Initiative, were generated for all 50 patients/four ROIs/eight GLs. Voxel intensity in SPECT images is the number of counts, which is a patient-dependent nonnormalized quantity. Thus, (i) fixed number of bin quantization must be chosen over fixed bin-width, and (ii) non-normalized statistical features should be excluded. The intra-class correlation (ICC) type C-1 calculated for all features between (a) all four ROIs and (b) between all except ${ROI}_{-1}$ showed 204 features with (a) ICC >0.7 and (b) ICC >0.85, respectively. However, a subset of 204 features with emphasis on high GLs across higher-order feature classes should be further excluded due to the scarce presence of voxels with high intensities that can appear due to missegmentation. Moreover, reproducibility analysis of quantization using Spearman rank-correlation showed GLs below 32 should be avoided due to high variation. The resulting features and settings are recommended for further investigation of predictive value.

An important aspect of differentiated thyroid cancer (DTC) management is disease localization by imaging. Functional imaging of thyroid cancer with iodinated radiotracers has been employed for metastatic disease detection for long. More recently, 2-deoxy-2-[18F] fluoro-d-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT), a non-iodinated ubiquitous PET tracer, has been used to detect non-radioiodine (RAI) avid disease. Advances in molecular imaging have led to the development of newer tracers like 18F-TFB (18F-tetrafluoroborate) that are transported through the sodium–iodide symporter (NIS) as well as 68 Ga-DOTATATE that image the somatostatin receptors sub-type 2 expressed in medullary thyroid cancer and some DTC. In coming years, there will be focus on newer receptor targets like prostate-specific membrane antigen expression and endoradiotherapies and theranostics.

Three-dimensional (3D) CT with volume rendering and maximum intensity projection is an integral component of CT interpretation for diagnosis and treatment planning of vascular pathology. Cinematic rendering is a new rendering algorithm that incorporates a more advanced lighting model than that used for volume rendering, to create photorealistic 3D CT images. The post-processing tool is not yet widely available and its ultimate clinical utility has yet to be assessed in well-designed studies. Nonetheless, the striking level of detail and enhanced depiction of 3D anatomic relationships holds potential for improvements in diagnosis, interventional or operative planning and patient-centred care. In this pictorial essay, a series of complex cardiovascular cases are presented to demonstrate the enhanced display capabilities associated with cinematic rendering, and the utility to guide patient management and understanding is discussed.

The differential diagnosis of solid renal neoplasms in adolescence includes aggressive malignancy and indolent oncocytic tumors, which are typically indistinguishable using conventional imaging. We report the use of

Multiparametric MRI (mpMRI) is currently the test of choice for imaging sites of prostate cancer located within the pelvis. However, molecular imaging with PET radiotracers that bind to prostate-specific membrane antigen is increasingly being used for this purpose and may compliment mpMRI findings. We present a case of a 59-year-old man with elevated postprostatectomy serum prostate-specific antigen level who was found on both mpMRI and prostate-specific membrane antigen-targeted PET to harbor residual prostate cancer in the corpus spongiosum along the proximal urethra.

Background 99mTc-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has recently been explored for the characterization of indeterminate renal masses. As judged by increased intra-tumoral radiotracer uptake, we have previously reported the excellent diagnostic performance characteristics of this test for identifying benign/indolent oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs). In this study, we investigated potential molecular mechanisms underlying the discriminatory ability of 99mTc-sestamibi SPECT/CT for renal masses. Fifty renal masses imaged with 99mTc-sestamibi SPECT/CT prior to surgical resection were evaluated by immunohistochemistry for mitochondrial content and expression of the multi-drug resistance pump 1 (MDR1/P-gp). Immunohistochemical staining was scored semi-quantitatively, and results were compared across renal tumor histologies and correlated with 99mTc-sestamibi uptake. Results In total, 6/6 (100%) and 2/2 (100%) HOCTs demonstrated strong mitochondrial content staining combined with low MDR1 staining. Clear cell renal cell carcinoma showed an opposite pattern with the majority having low mitochondrial (14/26, 54%) and high MDR1 staining (18/26, 69%). Other tumor types were more variable in staining pattern, although the staining pattern reliably predicted 99mTc-sestamibi uptake in almost all tumors except chromophobe renal cell carcinoma. Conclusions Our findings confirm that renal tumors with high mitochondrial content and relatively low MDR pump expression activity accumulate 99mTc-sestamibi and allow for the accurate diagnosis of the benign/indolent tumor class that includes oncocytomas and HOCTs. For masses in which MDR activity outweighs the presence of mitochondria, the tumors appear cold on 99mTc-sestamibi SPECT/CT, allowing for high confidence in the diagnosis of renal cell carcinoma.

Therapeutic options in advanced medullary thyroid carcinoma (MTC) have markedly improved since the introduction of tyrosine kinase inhibitors (TKIs). We aimed to assess the role of metabolic imaging using

Multi-detector computed tomography (MDCT) scanners that can quickly acquire volumetric datasets composed of isotropic voxels laid the groundwork for the widespread clinical implementation of 3D MDCT reconstructions, with maximum intensity projection (MIP) and volumetric rendering (VR) becoming important parts of the imaging evaluation of patients with a wide variety of pathologic conditions. Recently, a new 3D reconstruction technique known as cinematic rendering (CR) has become available and is now U.S. FDA approved. CR bears fundamental similarities to VR, but utilizes a more complex lighting model to bring about photorealistic reconstructions. While a tremendous amount of work remains to be done in order to understand the advantages and disadvantages of CR in comparison to traditional 3D reconstruction methods, the images themselves are strikingly detailed and can be interactively manipulated to highlight a variety of different tissue types and anatomic structures. In the following pictorial essay, we provide a number of clinical examples of the use of CR in musculoskeletal imaging, including the evaluation of complex fractures, the delineation of the relationship of fractures to adjacent vasculature and overlying soft tissues, and the visualization of vascular and soft tissue injuries.

Estrogen promotes bone health, long-term replacement delaying osteoporosis,1 while sex steroids given for menstrual irregularity to premenopausal women increase bone mass.2 We therefore assessed the relation between reproductive health and fracture risk in postmenopausal women (≥50 years) in the US National Health and Nutrition Examination Survey (NHANES).3 In the 2013–2014 survey, fracture risk as FRAX scores4 was reported in an osteoporosis questionnaire with calculation of the 10-year risk of major hip fracture. We collected data on the age at last menstrual period, last live birth, and first live birth as continuous variables, and documented history of pregnancy …

Prostate-specific membrane antigen (PSMA) has been explored as a target for molecular imaging of prostate cancer and other malignancies that express PSMA in their tumor-associated neovasculature. Although several PSMA-targeted radiotracers labeled with a variety of radionuclides have been reported, positron-emitting radiotracers labeled with

Altered function of the alpha7 nicotinic acetylcholine receptor (α7-nAChR) is implicated in several neuropsychiatric diseases. Nevertheless, studies of the human cerebral α7-nAChR even in healthy aging are limited in number and to postmortem tissue.The distribution of the cerebral α7-nAChR was estimated in nine brain regions in 25 healthy volunteers (ages 21-86 years; median 57 years, interquartile range 52 years) using [A negative correlation between tissue volume ratio and age was observed in six of the nine brain regions including striatum and five cortical (temporal, occipital, cingulate, frontal, or parietal) regions. A positive correlation between [Our results suggest an increase in cerebral α7-nAChR distribution over the course of healthy aging that should be tested in future longitudinal studies. The preservation of the α7-nAChR in the aging human brain supports the development of therapeutic agents that target this receptor for use in the elderly. Further study of the relationship between α7-nAChR availability and cognitive impairment over aging is needed.

18F-DCFPyL is a small-molecule inhibitor of the prostate-specific membrane antigen that has shown promise for evaluation of primary and metastatic prostate cancer using PET. Measuring the variability in normal-organ uptake of 18F-DCFPyL is necessary to understand its biodistribution, aid image interpretation, judge the reliability of scan quantification, and provide a basis for therapeutic monitoring. Methods: Sixty-five consecutive 18F-DCFPyL PET/CT scans from 64 patients with a history of prostate cancer were analyzed. Volumes of interest were defined for the lacrimal glands, major salivary glands, liver, spleen, and both kidneys. The mean SUV normalized to body mass or to lean body mass (SUL) was calculated for each volume of interest. The average SUV across all scans, the SD, and the coefficient of variation (COV) for each organ were calculated. The same parameters were also derived for a 3-cm sphere drawn in the center of the right lobe of the liver. Results: The average SUVmean for all selected organs measured was 6.6 ± 1.8 for the right lacrimal gland, 6.4 ± 1.8 for the left lacrimal gland, 9.1 ± 2.0 for the right parotid gland, 9.0 ± 2.1 for the left parotid gland, 9.6 ± 2.3 for the right submandibular gland, 9.4 ± 2.2 for the left submandibular gland, 5.0 ± 0.7 for the whole liver, 5.1 ± 0.7 for a 3-cm sphere in the liver, 4.0 ± 1.5 for the spleen, 20.1 ± 4.6 for the right kidney, and 19.4 ± 4.5 for the left kidney. SULmean was lower overall, although demonstrating similar trends. The COV of SUVmean and SULmean was lower in the liver (13.8% and 14.5%, respectively) than in any other organ and was less than the comparable COV for 18F-FDG PET. The COV of SUVmean and SULmean in the 3-cm sphere in the liver was also low and similar to the variability in the whole liver (14.2% and 14.7%, respectively). Conclusion: 18F-DCFPyL uptake in normal liver demonstrates less variability than in other 18F-DCFPyL–avid organs, and its variability is less than the reported variability of 18F-FDG in liver. Variability was slightly less for SUVmean than for SULmean, suggesting that SUVmean may be the preferable parameter for quantification of images obtained with 18F-DCFPyL.

We present the case of a 79-year-old man with an elevated postprostatectomy prostate-specific antigen level who was sequentially imaged with positron emission tomography/computed tomography (PET/CT) using

Purpose We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale of the voxel size. In particular, we investigated an anatomic region-of-interest (ROI) defined in a single transaxial slice, and a single sphere placed inside the organ boundaries. Methods The evaluation was carried out using Monte Carlo simulations based on patient indium 111In pentetreotide SPECT and computed tomography (CT) images. We modeled constant activity concentrations in each organ, validating this assumption by comparing the distribution of voxel values inside the organ VOIs of the simulated data with the patient data. We simulated projection data corresponding to 100, 50, and 25% of the clinical count level to study the effects of noise level due to shortened acquisition time. Images were reconstructed using a previously-validated quantitative SPECT reconstruction method. The evaluation was performed in terms of the accuracy and precision of the activity concentration estimates. Results The results demonstrated that the non-uniform image intensity observed in the reconstructed images in the organs with normal uptake was consistent with uniform activity concentration in the organs on the scale of the voxel size; observed non-uniformities in image intensity were due to a combination of partial volume effects at the boundaries of the organ, artifacts in the reconstructed image due to collimator-detector response compensation, and noise. Using an ROI defined in a single transaxial slice produced similar biases compared to the three-dimensional (3D) whole-organ VOIs provided that the transaxial slice was near the central plane of the organ and that the pixels from the organ boundaries were not included in the ROI. Although this slice method was sensitive to noise, biases were less than 10% for all the noise levels studied. The use of spherical VOIs was more sensitive to noise. The method was more accurate for larger spheres and larger organs such as the liver in comparison to the kidneys. Biases lower than 7% were found in the liver when using large enough spheres (radius ≥ 28mm) regardless of the position of the VOI inside the organ even with shortened acquisition times. The biases were more position dependent for smaller organs. Conclusions Both of the simpler methods provided suitable surrogates in terms of accuracy and precision. The results suggested that a spherical VOI was more appropriate for estimating the activity concentration in larger organs such as the liver, regardless of the position of the sphere inside the organ. Larger spheres resulted in better estimates. A single-slice ROI was more suitable for activity estimation in smaller organs such as the kidneys, providing that the transaxial slice selected was near the central plane of the organ and that voxels from the organ boundaries were excluded. Under those conditions, activity concentrations with biases lower than 5% were observed for all the studied count levels and coefficients of variation were less than 9% and 5% for the 25% and 100% count levels, respectively. This article is protected by copyright. All rights reserved.

The rapidly expanding clinical adaptation of prostate-specific membrane antigen (PSMA)-targeted PET imaging in the evaluation of patients with prostate cancer has placed an increasing onus on understanding both the potential pearls of interpretation as well as limitations of this new technique. As with any new molecular imaging modality, accurate characterization of abnormalities on PSMA-targeted PET imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants of radiotracer uptake, and potential sources of false-positive and false-negative imaging findings. In recent years, a growing number of reports have come to light describing incidental non-prostatic benign or malignant pathologies with high uptake on PSMA-targeted PET imaging. In this review, we have summarized the published literature regarding the potential pearls and technical and interpretive pitfalls of this imaging modality. Knowledge of these limitations can increase the confidence of interpreting physicians and thus improve patient care. As PSMA-targeted PET is expected to be evaluated in larger prospective trials, the dissemination of potential diagnostic pitfalls and the biologic underpinning of those findings will be of increased importance.

Prostate cancer (PCa) is the most common noncutaneous malignancy diagnosed in men. Despite the large number of men who will suffer from PCa at some point during their lives, conventional imaging modalities for this important disease (contrast-enhanced computed tomography, bone scan, and MR imaging) have provided only marginal to moderate success in appropriately guiding patient management in certain clinical contexts. In this review, the authors discuss radiofluorinated small molecule radiotracers that have been developed to bind to the transmembrane glycoprotein prostate-specific membrane antigen, a target that is nearly universally overexpressed on PCa epithelial cells.

Following single-lung transplantation (SLT), there is significant redistribution of flow preferentially to the transplanted lung. Altered lung perfusion leads to unusual results when performing pulmonary scintigraphy, which could result in interpretation errors. We present pulmonary scintigraphy images from a 67-year-old female patient with history of chronic obstructive pulmonary disease that were obtained before SLT, 10 days after SLT, and 3 months after SLT.

The prostate-specific membrane antigen (PSMA) is highly expressed on most prostate cancer (PC) cells. Therefore, the targeting of PSMA has become increasingly important over the last decade. Glu-urea-based PSMA ligands used for both imaging and radioligand therapy are the mainstays of the current success. For PET imaging, both 68Ga- and 18F-labeled agents have been successfully translated to clinical applications. Mainly retrospective cohort studies have shown a high value in the setting of biochemical recurrence, with high detection rates even in the presence of low prostate-specific antigen levels. Preliminary data indicated that radioguided surgery with PSMA ligands may help to further improve patient outcomes because it facilitates the removal of small tumor deposits that are otherwise difficult to detect. For primary PC, PSMA ligand PET imaging has been shown to be superior to cross-sectional imaging for the detection of metastatic lymph nodes. In addition, it promises to also provide intraprostatic tumor localization, especially when used in combination with multiparametric MRI. Increasing numbers of studies have reported considerable changes in management resulting from PSMA ligand PET imaging for both biochemical recurrence and primary disease. The use of 177Lu-PSMA-based radioligand therapy has demonstrated a reasonable response, mainly as defined by a prostate-specific antigen response of more than 50%, comparable to other recently introduced agents. Especially given the high level of safety of 177Lu-PSMA radioligand therapy, with only minimal grade 3 and 4 toxicities reported so far, it has the potential to expand options for metastatic castration-resistant PC. This review is intended to provide a comprehensive overview of the current literature on low-molecular-weight PSMA ligands for both PET imaging and therapeutic approaches, with a focus on agents that have been clinically adopted.

Purpose This study investigates whether the addition of preoperative Tc-MIBI SPECT/CT can increase the degree of diagnostic confidence in the differentiation of benign from malignant enhancing renal masses. Patients and methods Patients were recruited as part of an institutional review board-approved prospective clinical trial. Forty-eight patients with clinical stage T1 solid renal masses who underwent a Tc-MIBI SPECT/CT before partial or radical nephrectomy were evaluated. Conventional CT and MRI, which were approximately performed within 8 weeks before Tc-MIBI, were retrospectively retrieved. Based on a 5-point scale (1 = definitely benign, 5 = definitely malignant), 2 blinded readers recorded their degree of confidence for each lesion using conventional imaging before and after reviewing the Tc-MIBI uptake ratios. Surgical pathology was considered as the reference standard. Results Additional review of Tc-MIBI SPECT/CT uptake ratios increased diagnostic confidence in the differentiation of solid renal masses in 14/48 lesions (29.2%). In 9 lesions, the addition of Tc-MIBI changed the initial confidence levels of malignancy toward benign diagnosis. Postsurgical pathology confirmed the diagnosis of benign histology (oncocytoma/hybrid oncocytic-chromophobe tumors) in 7 and chromophobe renal cell carcinoma (behave as indolent) in 2 of these lesions. Tc-MIBI increased the confidence level toward malignancy in 5 cases; all were confirmed as RCC on surgical pathology. The area under the receiver operative characteristic curve was 0.60 for conventional imaging alone and 0.85 after reviewing Tc-MIBI (P for difference = 0.03). Conclusions Preoperative Tc-MIBI SPECT/CT enhances the performance of conventional imaging, improving the characterization of benign histologies and lowering the possibility of misclassification.

The differentiation of benign and indolent renal masses from aggressive tumor histologies cannot be reliably performed by CT or MRI. Additionally, renal mass biopsy risks complications and has a nondiagnostic rate of 10% to 20%. Tc-MIBI SPECT/CT has been shown to allow for the accurate differentiation of benign renal oncocytomas and hybrid oncocytic/chormophobe tumors from other more aggressive renal tumor types. We present the case of an 84-year-old man with chronic kidney disease and an 11.2-cm renal mass. Results of his Tc-MIBI SPECT/CT allowed avoidance of a radical nephrectomy.

To estimate the proportion of oncocytic renal neoplasms diagnosed on renal mass biopsy (RMB) confirmed on surgical pathology, a systematic review of MEDLINE, Embase, and the Cochrane databases (1997 to 1 July 2016) was conducted quantifying all cases of reported oncocytic renal neoplasms on RMB suggestive of an oncocytoma. In addition, institutional data was assessed to identify additional cases. Concordance with surgical histopathology (positive predictive value [PPV]) was evaluated for patients undergoing surgery by performing a meta-analysis. In all, 10 RMB series, including institutional data, were included in the meta-analysis with 205 RMBs identifying oncocytic renal neoplasms and 46 (22.4%) proceeding to surgery. One additional study identified two neoplasms not captured by the primary RMB series for a total of 48 unique lesions included in the analysis. Surgical pathology showed oncocytoma (64.6%), chromophobe renal cell carcinoma (RCC; 12.5%), other RCC (12.5%), hybrid oncocytic/chromophobe tumour (6.3%), and other benign lesions (4.2%). PPV of oncocytoma on RMB was 67% (95% confidence interval 34-94%) with significant heterogeneity between studies (I2 = 71.8%, P < 0.01). Risk of bias was judged to be low for four of the 10 series. Confidently diagnosing a localised renal mass as a benign lesion, such as an oncocytoma, has implications for the ultimate management strategy a patient will undergo. RMB was found to be unreliable in confidently diagnosing a localised renal mass as an oncocytoma, with one in four found to be RCC on surgical pathology. Patients and physicians should be aware of the uncertainty in diagnosis when considering management strategies.

Three-dimensional representations of volumetric CT data provide a powerful means to display and perceive complex anatomy and pathology. The development of advanced, multi-slice CT scanners that could rapidly acquire isotropic data sets without significant patient respiratory or voluntary motion has allowed for the implementation of a number of 3D reconstruction methods into clinical practice. In this chapter, we will discuss the technical considerations that underlie the most common 3D reconstruction methodologies (including surface rendering, maximum intensity projection, volume rendering, and cinematic rendering), the similarities and differences between these methodologies and how this impacts the types of imaging data each methodology is most suited to evaluate, and provide examples of some of the most common clinical uses of these techniques.

Targeting the prostate-specific membrane antigen (PSMA) with 68Ga-labeled and 18F-labeled PET agents has become increasingly important in recent years. Imaging of biochemically recurrent prostate cancer has been established as a widely accepted clinical indication for PSMA ligand PET/CT in many parts of the world because of the results of multiple, primarily retrospective, studies that indicate superior detection efficacy compared with standard-of-care imaging. For high-risk primary prostate cancer, evidence is growing that this modality significantly aids in the detection of otherwise occult nodal and bone metastases. For both clinical indications in recurrent as well as in primary prostate cancer, preliminary data demonstrate a substantial impact on clinical management. Emerging data imply that intraprostatic tumor localization, therapy stratification, and treatment monitoring of advanced disease in specific clinical situations might become future indications. Current criteria for image reporting of PSMA ligand PET are evolving given the expanding body of literature on physiologic and pathologic uptake patterns and pitfalls. This article intends to give an educational overview on the current status of PSMA ligand PET imaging, including imaging procedure and interpretation, clinical indications, diagnostic potential, and impact on treatment planning.