Exploring the Labyrinth: Imaging in Systemic Vasculitis.

Systemic vasculitis is an immune-mediated group of disorders broadly classified based on the involved vessel type. It has myriad clinical presentations, adding to the challenge of timely diagnosis and management. Thus, imaging has taken center stage in the diagnosis of these disorders as there is a lack of definitive clinical diagnostic markers. Various available imaging modalities can be used for diagnosis and follow-up on these patients. The coronavirus disease 2019 (COVID-19) has added a new dimension to the already existing problem of vasculitis. The virus has shown great affinity for the vascular endothelium, leading to multisystem organ vasculitis. There has been a spike in vasculitis cases in the COVID-19 pandemic era, thus necessitating more research and studies in this field for a better understanding of the disease. In this review, we wish to summarize the various imaging spectrums of classical systemic vasculitis along with the new addition of COVID-19-related vasculitis to the already long list.

Assessment of renal allograft rejection with diffusion tensor imaging.

OBJECTIVES: To investigate the value of DTI in differentiation of renal allograft rejection from well-functioning stable allograft, using fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values. METHODS: In this prospective study, 22 transplant recipients with well-functioning stable allograft (group A) and 20 patients with renal allograft rejection (group B + C) were recruited over a period of 19 months from January 2018 to July 2019. DTI-MRI was performed in all the patients, and FA and ADC values were measured in cortical and medullary regions of the transplanted kidney. On biopsy, graft rejection was classified as acute (group B) (n = 7) and chronic graft rejection (group C) (n = 13) based on the BANNF scoring system. Statistical analysis was performed using STATA v.14.0. RESULTS: Statistically significant difference between group A and group B + C was noted for cortical (p < 0.001), and medullary (p = 0.003) FA values, and cortical (p = 0.020), and medullary (p = 0.046) ADC values. Cortical(p < 0.001) and Medullary(p = 0.020) FA values showed statistically significant difference between group A and group C, and cortical FA value(p = 0.012) also showed statistically significant difference between group B and group C. AUC (to differentiate between renal allograft rejection and well-functioning stable allograft) for cortical, and medullary FA values and cortical and medullary ADC values were 0.853(p < 0.001), 0.757(p = 0.004), 0.709(p = 0.021) and 0.736(p = 0.009), respectively. CONCLUSION AND ADVANCES IN KNOWLEDGE: DTI is a promising functional MRI technique for the non-invasive assessment of renal allograft function. Diffusion parameters, such as FA and ADC values, can be useful in the differentiation of renal allograft rejection from well-functioning stable allograft.

Imaging of hydatid cyst of kidney, ureter and urinary bladder.

Renal hydatid is an uncommon finding, reported in less than 5% patients with hydatid infection. Hydatid involvement of ureter and urinary bladder is an even rarer entity. Renal hydatid is typically unilateral, solitary and arises from cortex. It is essential to be aware of the imaging features of the hydatid cyst for proper diagnosis. Knowledge of the imaging features of various stages is essential since treatment decision is based on cyst stage. Hydatid cyst can mimic several entities both benign and malignant. We present a pictorial review to illustrate the radiological imaging features of hydatid disease involving kidney, ureter and bladder region and its complications.

Unusual Primary Neoplasms of the Adult Liver: Review of Imaging Appearances and Differential Diagnosis.

The radiological appearance of common primary hepatic tumors such as hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) is widely recognized. Hepatic masses with unusual histology are occasionally encountered, but seldom suspected on imaging. However, many possess characteristic imaging findings, which when assessed along with the clinical and demographic background and serum tumor markers, may enable a prospective diagnosis. This review attempts to familiarize the reader with the clinicopathological characteristics, imaging manifestations, and differential diagnosis of these unusual liver tumors in adults. Biphenotypic primary liver carcinoma is suspected in masses showing distinct areas of HCC and CCA-type enhancement pattern in cirrhotic livers. Fibrolamellar carcinoma occurs in young individuals without underlying chronic liver disease and shows a characteristic T2-hypointense scar frequently showing calcification. Perivascular epithelioid cell tumors are differentials for any arterial hyperenhancing mass in the noncirrhotic liver, particularly in patients with tuberous sclerosis. Multifocal subcapsular tumors showing target-like morphology, capsular retraction and "lollipop" sign are suspicious for epithelioid hemangioendothelioma. On the other hand, multiple hemorrhagic lesions showing patchy areas of bizarre-shaped arterial phase hyperenhancement are suspicious for angiosarcoma. Primary hepatic lymphoma (PHL) is suspected when patients with immunosuppression present with solitary or multifocal masses that insinuate around vessels and bile ducts without causing luminal narrowing. Intense diffusion restriction and low-level homogeneous or target-like enhancement are also ancillary features of PHL. Primary hepatic neuroendocrine tumor shows uptake on Ga-68 DOTANOC PET/CT. Although a straightforward diagnosis may be difficult in these cases, awareness of the characteristic imaging appearances is helpful in suspecting the diagnosis.

Transvaginal Shear Wave Elastography for Assessment of Endometrial and Subendometrial Pathologies: A Prospective Pilot Study.

OBJECTIVE: To assess the role of shear wave elastography (SWE) in characterizing different endometrial and subendometrial pathologies. METHODS: Seventy-three women with pathologically proven endometrial and subendometrial pathologies were enrolled in this prospective study and assessed with transvaginal SWE. The elasticity values (in kiloPascals), and the ratio of mean elasticity of the endometrial lesion to myometrial elasticity (E/M ratio) were compared in different pathologies. RESULTS: There was a statistically significant difference (P <.001) in the mean, minimum, and maximum elasticity of the pathologies as well as the E/M ratio (P <.00001). In the analysis of the subgroups, the mean elasticity of endometrial polyp was statistically significantly lower than other subgroups (P <.01), while submucosal leiomyoma and focal adenomyoma had significantly higher values than other subgroups (P <.01). No statistically significant difference was noted in the mean elasticity of carcinoma and hyperplasia (P-.19). CONCLUSION: SWE is a potential adjunct to ultrasound that provides an additional paradigm to characterize endometrial and subendometrial masses.

Role of diffusion tensor imaging in the evaluation of ulnar nerve involvement in leprosy.

OBJECTIVE: Early detection of peripheral neuropathy is extremely important as leprosy is one of the treatable causes of peripheral neuropathy. The study was undertaken to assess the role of diffusion tensor imaging (DTI) in ulnar neuropathy in leprosy patients. METHODS: This was a case-control study including 38 patients (72 nerves) and 5 controls (10 nerves) done between January 2017 and June 2019. Skin biopsy proven cases of leprosy, having symptoms of ulnar neuropathy (proven on nerve conduction study) were included. MRI was performed on a 3 T MR system. Mean cross-sectional area, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of ulnar nerve at cubital tunnel were calculated. Additional ancillary findings and appearance of base sequences were evaluated. RESULTS: Ulnar nerve showed thickening with altered T2W signal in all the affected nerves, having an average cross-sectional area of 0.26 cm2. Low FA with mean of 0.397 ± 0.19 and high ADC with mean of 1.28 ± 0.427 x 10 -3 mm2/s of ulnar nerve in retrocondylar groove was obtained. In the control group, mean cross-sectional area was 0.71cm2 with mean FA and ADC of 0.53 ± 0.088 and 1.03 ± 0.24 x 10 -3 mm2/s respectively. Statistically no significant difference was seen in diseased and control group. Cut-off to detect neuropathy for FA and ADC is 0.4835 and 1.1020 × 10 -3 mm2/s respectively. CONCLUSION: DTI though is challenging in peripheral nerves, however, is proving to be a powerful complementary tool for assessment of peripheral neuropathy. Our study validates its utility in infective neuropathies. ADVANCES IN KNOWLEDGE: 1. DTI is a potential complementary tool for detection of peripheral neuropathies and can be incorporated in standard MR neurography protocol.2. In leprosy-related ulnar neuropathy, altered signal intensity with thickening or abscess of the nerve is appreciated along with locoregional nodes and secondary denervation changes along with reduction of FA and rise in ADC value.3. Best cut-offs obtained in our study for FA and ADC are 0.4835 and 1.1020 × 10 -3 mm2/s respectively.

IVIM-DKI for differentiation between prostate cancer and benign prostatic hyperplasia: comparison of 1.5 T vs. 3 T MRI.

OBJECTIVE: To implement an advanced spatial penalty-based reconstruction to constrain the intravoxel incoherent motion (IVIM)-diffusion kurtosis imaging (DKI) model and investigate whether it provides a suitable alternative at 1.5 T to the traditional IVIM-DKI model at 3 T for clinical characterization of prostate cancer (PCa) and benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Thirty-two patients with biopsy-proven PCa were recruited for MRI examination (n = 16 scanned at 1.5 T, n = 16 scanned at 3 T). Diffusion-weighted imaging (DWI) with 13 b values (b = 0 to 2000 s/mm2 up to 3 averages, 1.5 T: TR = 5.774 s, TE = 81 ms and 3 T: TR = 4.899 s, TE = 100 ms), T2-weighted, and T1-weighted imaging were used on the 1.5 T and 3 T MRI scanner, respectively. The IVIM-DKI signal was modeled using the traditional IVIM-DKI model and a novel model in which the total variation (TV) penalty function was combined with the traditional model to optimize non-physiological variations. Paired and unpaired t-tests were used to compare intra-scanner and scanner group differences in IVIM-DKI parameters obtained using the novel and the traditional models. Analysis of variance with post hoc test and receiver operating characteristic (ROC) curve analysis were used to assess the ability of parameters obtained using the novel model (at 1.5 T) and the traditional model (at 3 T) to characterize prostate lesions. RESULTS: IVIM-DKI modeled using novel model with TV spatial penalty function at 1.5 T, produced parameter maps with 50-78% lower coefficient of variation (CV) than traditional model at 3 T. Novel model estimated higher D with lower D*, f and k values at both field strengths compared to traditional model. For scanner differences, the novel model at 1.5 T estimated lower D* and f values as compared to traditional model at 3 T. At 1.5 T, D and f values were significantly lower with k values significantly higher in tumor than BPH and healthy tissue. D (AUC: 0.98), f (AUC: 0.82), and k (AUC: 0.91) parameters estimated using novel model showed high diagnostic performance in cancer lesion detection at 1.5 T. DISCUSSION: In comparison with the IVIM-DKI model at 3 T, IVIM-DKI signal modeled with the TV penalty function at 1.5 T showed lower estimation errors. The proposed novel model can be utilized for improved detection of prostate lesions.

Contrast-enhanced ultrasound in evaluation of adrenal lesions with CT/MRI correlation.

Most of the adrenal masses are incidentally detected. Multiphasic CT forms the mainstay for diagnosis and characterization of adrenal masses. MRI can further be used if the masses are indeterminate on CT scan. But as these investigations are expensive with risk of radiation exposure, contrast-enhanced ultrasound (CEUS) is currently under evaluation to assess its utility to act as a screening modality to differentiate benign vs malignant adrenal masses This investigative modality is relatively safe and can be used in patients having renal dysfunction or allergy to CT contrast. We, hereby, present a pictorial review of imaging appearance of various adrenal lesions on CEUS with CT and MRI correlation.

Evaluation of the Graft Kidney in the Early Postoperative Period: Performance of Contrast-Enhanced Ultrasound and Additional Ultrasound Parameters.

OBJECTIVES: To evaluate the various quantitative parameters of Doppler ultrasound, contrast-enhanced ultrasound (CEUS), and shear wave elastography (SWE) of graft kidneys in the early postoperative period and to explore their utility in the diagnosis of parenchymal causes of graft dysfunction. METHODS: In this ethically approved study, consecutive patients who underwent renal transplantation from March 2017 to August 2018 were recruited, and those with urologic or vascular complications and those who denied consent were excluded. All patients underwent ultrasound with Doppler, SWE, CEUS (using sulfur hexafluoride), and renal scintigraphic examinations 3 to 10 days after transplantation. A composite reference standard was used, including the clinical course, renal function test results, urine output, and histopathologic results for graft dysfunction. Cortical SWE values, quantitative CEUS parameters (generated from a time-intensity curve), and their ratios were analyzed to identify graft dysfunction and differentiate acute tubular necrosis (ATN) from acute rejection (AR). RESULTS: Of the 105 patients included, 19 developed graft dysfunction (18.1%; 12 ATN, 5 AR, and 2 drug toxicity) in the early postoperative period. The peak systolic velocity in the interpolar artery showed a significant difference between control and graft dysfunction groups (P < .001) as well as between ATN and AR (P = .019). Resistive indices and SWE did not show significant differences. Ratios of the time to peak showed a significant difference between control and graft dysfunction groups (P < .05). The rise time and fall time of the large subcapsular region of interest and the rise time ratio were significantly different between ATN and AR (P = .03). CONCLUSIONS: Contrast-enhanced ultrasound can be used to diagnose parenchymal causes of early graft dysfunction with reasonable diagnostic accuracy.

Multiparametric Magnetic Resonance Imaging, 68Ga Prostate-Specific Membrane Antigen Positron Emission Tomography-Computed Tomography, and Respective Quantitative Parameters in Detection and Localization of Clinically Significant Prostate Cancer in Intermediate- and High-Risk Group Patients: An Indian Demographic Study.

OBJECTIVES: The objective of this study was to evaluate the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) and 68Ga prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET-CT) and respective quantitative parameters (Ktrans - influx rate contrast, Kep - efflux rate constant, ADC - apparent diffusion coefficient, and SUVmax ratio - prostate SUVmax to background SUVmax ratio) in detection and localization of clinically significant prostate cancer (CSPCa) in D'Amico intermediate- and high-risk group patients (prostate-specific antigen [PSA] >10 ng/ml). METHODOLOGY: The study included thirty-three consecutive adult men with serum prostate specific antigen >10ng/ml, and systematic 12 core prostate biopsy proven prostate cancer. All the 33 patients, were evaluated with mpMRI, and 68Ga PSMA PET-CT. The biopsy specimens and imaging were evaluated for 12 sectors per prostate by a predetermined scheme. RESULTS: MpMRI Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) score ≥3 showed higher sensitivity than 68Ga PSMA PET-CT (96.3% vs. 82.4%), with similar specificity (54.5% vs. 54.5%) (n = 33 patients, 396 sectors). Combined use of MRI and 68Ga PSMA PET-CT in parallel increased sensitivity (99.5%) and NPV (98.7%) for detection of CSPCa and combined use of MRI and 68Ga PSMA PET-CT in series increased specificity (71.8%) and PPV (71.5%) (n = 33 patients, 396 sectors). ADC showed a strong negative correlation with Gleason score (r = -0.77), and the highest discriminative ability for detection and localization of CSPCa (area under curve [AUC]: 0.91), followed by Ktrans (r = 0.74; AUC: 0.89), PI-RADS (0.73; 0.86), SUVmax ratio (0.49; 0.74), and Kep (0.24; 0.66). CONCLUSION: MpMRI PI-RADS v2 score and 68Ga PSMA PET-CT (individually as well as in combination) are reliable tool for detection and localization of CSPCa. Quantitative MRI and 68Ga PSMA PET-CT parameters have potential to predict Gleason score and detect CSPCa.

Normalized apparent diffusion coefficient: a novel paradigm for characterization of endometrial and subendometrial lesions.

OBJECTIVES: To assess the role of normalized apparent diffusion coefficient (ADC) in characterization of endometrial and subendometrial masses, measured as a ratio of the mean ADC of the pathology to mean ADC of two different internal controls, normal myometrium and gluteus maximus muscle, referred to as nADCm and nADCg respectively. METHODS: 55 females with pathologically proven endometrial and subendometrial lesions, including 27 cases of endometrial carcinoma, and 28 cases of benign masses were enrolled in this prospective study and assessed with single-shot echoplanar diffusion-weighted imaging. The normalized and absolute ADC of the lesions, measured by two radiologists, were compared in different pathologies and receiver operating characteristics (ROC) performed to distinguish benign and malignant endometrial masses. In the endometrial carcinoma group, the ADC values were further compared with tumor grade and subtype. RESULTS: There was good interobserver agreement (>0.800) for both internal controls, however it was higher for myometrium [intraclass correlation coefficient-0.92; confidence interval (0.86-0.95)] than gluteus maximus muscle [ICC-0.84; CI (0.72-0.90)]. There were statistically significant differences in absolute ADC (p-0.02), nADCm (p-0.02) and nADCg (p < 0.0001) of benign and malignant endometrial masses. CONCLUSION: Normalized ADC is useful to distinguish benign and malignant masses with comparable accuracy as absolute ADC. ADVANCES IN KNOWLEDGE: Normalized ADC represents an easily measurable quantitative parameter which limits the influence of endogenous and exogenous factors that affect its reproducibility.

Inguinal Canal Deposit-An Uncommon Site of Metastases in Carcinoma Prostate Detected on 68Ga-Prostate-Specific Membrane Antigen PET/CT.

Metastatic deposit in the inguinal canal is an uncommon finding. Few tumors such as pancreatic cancer, rectal cancer, and ovarian cancer have been described previously with metastatic inguinal canal deposit. We present here a case of prostate cancer with an uncommon inguinal canal deposit that was detected on Ga-prostate-specific membrane antigen PET/CT.

Posterior Reversible Encephalopathy Syndrome: Pattern on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography Correlated with Magnetic Resonance Imaging in Pediatric Hypertensive Encephalopathy.

Posterior reversible encephalopathy syndrome (PRES) is characterized clinically by headache, seizures, vomiting, altered mental status, and blurred vision. However, with overlapping and atypical clinical symptoms, PRES becomes a diagnostic challenge. We describe the imaging findings of PRES in magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography-computed tomography in an 11-year-old child who presented with features of hypertensive encephalopathy.

Drooping shoulders: A rare manifestation of an uncommon disease.

Primary systemic amyloidosis is an uncommon disease which presents with involvement of the kidney, heart, peripheral nervous system and liver. The involvement of skeletal muscles called amyloid myopathy is uncommon. We report a 74-year-old male who presented with progressively drooping shoulders followed by other muscular involvement without other organ involvement as a manifestation of amyloidosis. The patient was managed with melphalan, prednisolone and thalidomide with clinical improvement.

Quantitative Sonoelastographic Assessment of the Normal Uterus Using Shear Wave Elastography: An Initial Experience.

OBJECTIVES: To describe the sonoelastographic characteristics of the normal endometrium, myometrium, and cervix and to assess their variability with age and different menstrual phases. METHODS: A total of 56 women were enrolled in this prospective study, who underwent transvaginal ultrasound examinations, including B-mode imaging and shear wave elastography. The elasticity parameters (in kilopascals) of the normal endometrium, myometrium, and cervix were studied. The variability of the mean elasticity value of the endometrium in different menstrual phases and age groups was analyzed. The variability of the mean elasticity of the cervix across different age groups was also studied. RESULTS: The mean age of the participants was 40 years (range, 25-69 years). The normal mean elasticity values ± SDs were 25.54 ± 8.56 kPa for the endometrium, 40.24 ± 8.59 kPa for the myometrium, and 18.90 ± 4.22 kPa for the cervix. A mean endometrial-to-myometrial elasticity ratio was calculated, which was found to be 0.65 ± 0.22. There was no significant difference in the mean endometrial elasticity values for women in different menstrual phases (P = .176) or in different age groups (P = .376). There was no significant difference in the mean cervical elasticity with age (P = .192). CONCLUSIONS: Shear wave elastography is a promising adjunct to ultrasound for the evaluation of the uterus, and the results from this study may provide normal data, which may further help in diagnosing various uterine diseases.

Serum creatinine and cystatin C-based index can be a screening biomarker for sarcopenia in older population.

PURPOSE: Considering the clinical impact of sarcopenia, it would be interesting to get a rapid and sensible screening tool. We conducted a cross-sectional study with the motive to use an index based on serum creatinine and cystatin C to screen sarcopenia in older people in outpatient settings. METHODS: 100 participants above the age of 65 years were recruited from the outpatient department of Geriatric medicine of a tertiary care hospital in India. Muscle mass, muscle strength and physical performance were measured by DXA scan, hand-held dynamometer and 4 m gait speed, respectively. Sarcopenia was identified using Asian working group of sarcopenia (AWGS) criteria. Serum creatinine and cystatin C were measured for all participants. Serum creatinine/cystatin C ratio and biochemical total body muscle mass index (TBMM) were calculated and its association was checked with sarcopenia. RESULTS: The prevalence of sarcopenia was 53%. Mean serum creatinine/cystatin C ratio was 74.79 ± 24.91. It was not significantly associated with sarcopenia. Mean biochemical TBMM index of participants was 36.40 ± 7.88 (males-38.77 ± 7.72, females-31.22 ± 5.13). The lower value of biochemical TBMM index was significantly associated with an increased risk of sarcopenia (p < 0.01). Cut-off value of 40.9 in males (sensitivity-79.41%; specificity-61.76%) and 32.2 in females (sensitivity-78.95%; specificity-66.67%) was proposed for identification of sarcopenia. CONCLUSION: Out of the two indices, only low biochemical total body muscle mass index is significantly associated with sarcopenia and a value of less than 40.9 in males and 32.2 in females can be used to screen sarcopenia in older people.

Can Early Dynamic Positron Emission Tomography/Computed Tomography Obviate the Need for Postdiuresis Image in 68Ga-PSMA-HBED-CC Scan for Evaluation of Prostate Adenocarcinoma?

INTRODUCTION: Forced diuresis technique is often adopted to wash out the high amount of urinary radioactivity that masks the foci of abnormal uptake in the pelvic region on 68Ga-PSMA-HBED-CC positron emission tomography/computed tomography (PET/CT) scan in prostate cancer (PC) patients. However, this method is time-consuming, makes the patient non/less compliant, and is not feasible in patients with renal dysfunction. We hypothesized that early dynamic imaging can obviate the need for a postdiuresis view as the urinary activity is expected to be low at the time. MATERIALS AND METHODS: A total of 20 biopsy-proven PC patients who were referred to our department for a 68Ga-PSMA PET/CT for staging/restaging were prospectively studied. Dynamic PET/CT was done with on table intravenous (i.v.) injection of 2-3 mCi (74-111 MBq) of the radiotracer. Dynamic images were acquired over the pelvis with a frame time of 1 min for 10 min. Static images of 2 min/bed position were acquired between 45 and 60 min p.i. The patients were then administered i.v. furosemide and encouraged water intake and frequent urination. A static view of pelvic region was acquired at 5 min/bed at 120 min p.i. A three-dimensional volume of interest (3D-VOI) was plotted on the primary lesion, bladder, involved nodes if any, pelvic bones at involved and uninvolved sites, gluteal muscles, and artery. The sentence seems fine. This was to generate the Time activity curve for analysis. RESULTS: Nine patients were referred for staging and 11 for restaging. Mean age of 20 patients was 64.6 years, and median prostate-specific antigen level was 21.4 ng/ml (range: 0.05-2180). Prostatic lesion was present in 20 patients, nodal involvement in 8, and bone involvement in 10 patients. Median maximum standardized uptake value (SUVmax) of the prostatic lesion (P) showed an ascending trend: 5.31 at 5 min, 10.65 at 60 min, and 10.52 at 120 min p.i. At the same time, median SUVmax of the bladder (B) also progressed steeply and then decreased postdiuresis: 1.01 at 5 min, 24.6 at 60 min, and 6.88 at 120 min. Despite forced diuresis, the bladder activity remained higher than that during early dynamic imaging. Median prostate-to-bladder (P/B) ratio was highest during early dynamic imaging at 5 min p.i. was 5.17, while at 60 min, P/B ratio was 0.42 (P = 0.002) and, at 120 min, it was 1.27 (P = 0.009). Further, all the nodal and bone lesions were clearly visualized on early dynamic images. CONCLUSION: The study results suggest that early dynamic imaging performs better than a postdiuresis view in terms of delineation of prostatic and regional lesions on 68Ga-PSMA scan. Further, it saves time and the patients are more compliant to this technique.

Positron emission tomography in prostate cancer: An update on state of the art.

Prostate cancer (PCa), one of the most common cancers in males, is a topic of active interest in imaging research. Positron emission tomography/computed tomography (PET/CT) and PET/magnetic resonance imaging (PET/MRI) have enabled the combination of morphologic and functional imaging with the promise of providing better information in guiding therapy. 18F-fluorodeoxyglucose, the workhorse radiopharmaceutical in PET imaging, has not found preference in PCa since these tumors show poor glucose uptake and can be obscured by the normal urinary excretion of the radiotracer. Hence, the last two decades have seen the development of multiple newer radiotracers and better optimization of the technical aspects of PET imaging. The combination of functional imaging and MRI holds great promise. We searched PubMed, Scopus, and Google Scholar for peer-reviewed literature concerning the advances and newer developments in the imaging of PCa between the years 2005 and 2017. This review aims at summarizing current evidence on the role of PET imaging in PCa and its impact on the diagnosis, staging, prognostication, response assessment, and restaging of this malignancy.