Patterns of disease detection using [18F]DCFPyL PET/CT imaging in patients with detectable PSA post prostatectomy being considered for salvage radiotherapy: a prospective trial.

PURPOSE: Prostate-specific membrane antigen (PSMA) PET/CT is increasingly used in patients with biochemical recurrence post prostatectomy to detect local recurrence and metastatic disease at low PSA levels. The aim of this study was to assess patterns of disease detection, predictive factors and safety using [18F]DCFPyL PET/CT versus diagnostic CT in patients being considered for salvage radiotherapy with biochemical recurrence post prostatectomy. METHODS: We conducted a prospective trial recruiting 100 patients with detectable PSA post prostatectomy (PSA 0.2-2.0 ng/mL) and referred for salvage radiotherapy from August 2018 to July 2020. All patients underwent a PSMA PET/CT using the [18F]DCFPyL tracer and a diagnostic CT. The detection rates of [18F]DCFPyL PET/CT vs diagnostic CT were compared and patterns of disease are reported. Clinical patient and tumour characteristics were analysed for predictive utility. Thirty-day post-scan safety is reported. RESULTS: Of 100 patients recruited, 98 were suitable for analysis with a median PSA of 0.32 ng/mL. [18F]DCFPyL PET/CT was positive 46.4% and equivocal 5.2%, compared to 15.5% positivity for diagnostic CT. Local recurrence was detected on [18F]DCFPyL PET/CT in 28.5%, nodal disease in 27.5% and bony metastases in 6.1% of patients. Both ISUP grade group (p < 0.001) and pre-scan PSA (p = 0.029) were significant predictors of [18F]DCFPyL PET/CT positivity, and logistic regression generated probabilities combining the two showed improved prediction rates. No significant safety events were reported post [18F]DCFPyL administration. CONCLUSIONS: [18F]DCFPyL PET/CT increases detection of disease in patients with biochemical recurrence post prostatectomy compared to diagnostic CT. Patients being considered for salvage radiotherapy with a PSA >0.2 ng/mL should be considered for [18F]DCFPyL PET/CT scan. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry Number: ACTRN12618001530213 ( http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375932&isReview=true ).

Pleural small cell lung cancer masquerading as malignant mesothelioma: A case report.

Nodular soft tissue pleural thickening on imaging is highly suggestive of malignancy, of which pleural malignant mesothelioma and metastatic disease are differentials. We present the case of a 71-year-old male who presented with acute worsening of shortness of breath associated with a recurrent left pleural effusion post-pleurocentesis. He was an ex-smoker with previous asbestos exposure. Computed tomography performed demonstrated left-sided pleural thickening in the hemithorax and hemidiaphragm with complex pleural effusion. 18F-2-deoxy-d-glucose whole body PET scan revealed extensive uptake throughout the left hemithorax in multiple pleural masses. The imaging findings and clinical case were typical of malignant mesothelioma. However, histopathology results revealed small cell lung cancer. We need to be cognisant of this atypical presentation of a common disease entity. Even when all clinical and imaging findings point towards a certain diagnosis, histopathological assessment cannot be ignored.

Changes in Management After 18F-DCFPyL PSMA PET in Patients Undergoing Postprostatectomy Radiotherapy, with Early Biochemical Response Outcomes.

Prostate-specific membrane antigen (PSMA) tracers have increased sensitivity in the detection of prostate cancer, compared with conventional imaging. We assessed the management impact of 18F-DCFPyL PSMA PET/CT in patients with prostate-specific antigen (PSA) recurrence after radical prostatectomy (RP) and report early biochemical response in patients who underwent radiation treatment. Methods: One hundred patients were enrolled into a prospective study, with a prior RP for prostate cancer, a PSA of 0.2-2.0 ng/mL, and no prior treatment. All patients underwent diagnostic CT and PSMA PET/CT, and management intent was completed at 3 time points (original, post-CT, and post-PSMA) and compared. Patients who underwent radiotherapy with 6-mo PSA response data are presented. Results: Ninety-eight patients are reported, with a median PSA of 0.32 ng/mL (95% CI, 0.28-0.36), pT3a/b disease in 71.4%, and an International Society of Urological Pathology grade group of at least 3 in 59.2%. PSMA PET/CT detected disease in 46.9% of patients, compared with 15.5% using diagnostic CT (PSMA PET, 29.2% local recurrence and 29.6% pelvic nodal disease). A major change in management intent was higher after PSMA than after CT (12.5% vs. 3.2%, P = 0.010), as was a moderate change in intent (31.3% vs. 13.7%, P = 0.001). The most common change was an increase in the recommendation for elective pelvic radiation (from 15.6% to 33.3%), nodal boost (from 0% to 22.9%), and use of concurrent androgen deprivation therapy (ADT) (from 22.9% to 41.7%) from original to post-PSMA intent because of detection of nodal disease. Eighty-six patients underwent 18F-DCFPyL-guided radiotherapy. Fifty-five of 86 patients either did not receive ADT or recovered after ADT, with an 18-mo PSA response from 0.32 to 0.02 ng/mL; 94.5% of patients had a PSA of no more than 0.20 ng/mL, and 74.5% had a PSA of no more than 0.03 ng/mL. Conclusion: 18F-DCFPyL PET/CT has a significant impact on management intent in patients being considered for salvage radiotherapy after RP with PSA recurrence. Increased detection of disease, particularly in the pelvic lymph nodes, resulted in increased pelvic irradiation and concurrent ADT use. Early results in patients who are staged with 18F-DCFPyL PET/CT show a favorable PSA response.

The role of imaging in pulmonary hypertension.

Pulmonary hypertension (PH) is a debilitating and potentially life threatening condition in which increased pressure in the pulmonary arteries may result from a variety of pathological processes. These can include disease primarily involving the pulmonary vasculature, but more commonly PH may result from left-sided heart disease, including valvular heart disease. Chronic thromboembolic pulmonary hypertension (CTEPH) is an important disease to identify because it may be amenable to surgical pulmonary artery endarterectomy or balloon pulmonary angioplasty. Parenchymal lung diseases are also widespread in the community. Any of these disease processes may result in adverse remodeling of the right ventricle and progressive right heart (RH) failure as a common final pathway. Because of the breadth of pathological processes which cause PH, multiple imaging modalities play vital roles in ensuring accurate diagnosis and classification, which will lead to application of the most appropriate therapy. Multimodality imaging may also provide important prognostic information and has a role in the assessment of response to therapies which ultimately dictate clinical outcomes. This review provides an overview of the wide variety of established imaging techniques currently in use, but also examines many of the novel imaging techniques which may be increasingly utilized in the future to guide comprehensive care of patients with PH.

Cardiac tamponade in multiple myeloma - A pictorial case review of FDG PET/CT findings.

Pericardial involvement of multiple myeloma is a rare and late-stage complication, with only a few cases reported in the literature. PET/CT has demonstrated a growing role in the diagnosis and follow-up of patients with multiple myeloma. We present a case of pericardial multiple myeloma in a patient with relapsed/refractory disease, showcasing previously unpublished FDG PET/CT findings.

Outcomes of incidental findings on multi-detector computed tomography for transcatheter aortic valve implantation assessment: A single-centre study and review of the literature.

INTRODUCTION: Patients with severe aortic stenosis (AS) require multi-detector computed tomography (MDCT) when considered for transcatheter aortic valve implantation (TAVI). Incidental findings on MDCT are common given the age group and region imaged. Our aim was to evaluate the frequency and outcome of incidental findings (IF) identified on MDCT and the impact on survival. METHODS: This single-centre analysis retrospectively reviewed severe AS patients who underwent MDCT during TAVI workup. MDCT reports were reviewed for any IF and defined into three categories: IF of no relevant clinical significance (IF-NoCS), IF of non-immediate clinical significance (IF-NICS) and IF of immediate clinical significance (IF-ICS). Demographics, follow-up of IF and survival were calculated from MDCT date. RESULTS: Two hundred and sixty-five patients underwent MDCT for TAVI suitability (mean age 83 ± 6 years, 52% male). The majority proceeded to TAVI (65%). Renal lesions (25%) and lung nodules (18%) were the most common IF. Fifty-nine patients (22%) had IF-NICS; 39% (23/59) were benign, 59% were not further investigated and one patient had suspected lung cancer. Six patients (2.3%) had IF-ICS and all were diagnosed with lung cancer. During a median follow-up of 272 days, there was no survival difference between patients with IF-ICS or IF-NICS versus patients without IF or IF-NoCS in the overall cohort (P = 0.44) or in TAVI patients (P = 0.88). CONCLUSION: Incidental findings on MDCT are common with one-quarter having IF-ICS or IF-NCIS. Most patients with IF-NICS did not undergo further investigation. Standardized reporting of MDCT may assist in clarifying the need for further investigation which will in turn influence decision and timing to proceed with TAVI.

Prevalence of non 18 F-fluorodeoxyglucose-avid incidental findings of clinical significance on whole body positron emission tomography/computed tomography: A review of 500 consecutive cases.

INTRODUCTION: The prevalence of incidental 18 F-fluorodeoxyglucose (FDG)-avid findings on positron emission tomography-computed tomography (PET/CT) has been extensively described. Few studies, however, have assessed the prevalence and significance of non-FDG-avid findings; pathology that is identified on review of the low-dose, non-contrast CT. The aim of this study was to determine the overall prevalence of non FDG-avid incidental findings on PET/CT and the prevalence of 'clinically significant' non FDG-avid pathology. METHODS: Five hundred consecutive whole body PET/CT studies performed in 2016 at a university affiliated tertiary hospital were retrospectively reviewed by two radiologists experienced in reporting PET/CT. Findings were categorized according to potential clinical relevance, and a targeted follow-up of clinically significant incidental findings was performed. RESULTS: Incidental findings were encountered in 463 of 500 (92.6%) patients. In 226 patients, these findings had been detected on previous imaging studies, with unknown incidental findings present in 237 of 500 (47.4%) patients. 113 of 500 (22.6%) patients had non-avid incidental findings of potentially major clinical significance, and in 35 patients (7.0%) these findings were considered previously unknown. The most common non-avid findings of potentially major significance were pulmonary nodules (6 mm or larger), moderate or large size pleural effusions, and vascular aneurysms. Unknown incidental findings of potentially major clinical significance were significantly higher in patients imaged for melanoma staging (P= 0.004). CONCLUSION: The prevalence of incidental findings of clinical significance that do not accumulate FDG in PET/CT is not insignificant. Routine systematic review of the low-dose CT is required to avoid missing potentially clinically important findings, in particular pleural effusions, vascular aneurysms and metastatic pulmonary nodules.

Prevalence of incidental or unexpected findings on low-dose CT performed during routine SPECT/CT nuclear medicine studies.

INTRODUCTION: In nuclear medicine, single-photon-emission computed tomography (SPECT) is often combined with 'simultaneous' low-dose CT (LDCT) to provide complementary anatomical and functional correlation. As a consequence, numerous incidental and unexpected findings may be detected on LDCT. Recognition of these findings and appropriate determination of their relevance can add to the utility of SPECT/CT. We aimed to evaluate the prevalence and categorise the relevance of incidental and unexpected findings on LDCT scans performed as part of routine SPECT/CT studies. METHODS: All available LDCT scans performed as part of SPECT/CT studies at St. Vincent's Hospital Melbourne in the year 2013 were retrospectively reviewed. Two qualified radiologists independently reviewed the studies and any previous available imaging and categorised any detected incidental findings. RESULTS: A total of 2447 LDCT studies were reviewed. The relevance of the findings was classified according to a modified version of a scale used in the Colonography Reporting and Data System: E1 = normal or normal variant (28.0%); E2 = clinically unimportant (63.5%); E3 = likely unimportant or incompletely characterised (6.2%); E4 = potentially important (2.5%). CONCLUSION: Imaging specialists need to be cognisant of incidental and unexpected findings present on LDCT studies performed as part of SPECT/CT. Appropriate categorisation of findings and communication of potentially important findings to referring clinicians should form part of routine practice. The overall prevalence of potentially significant incidental and unexpected findings in our series was 8.7% (E3, 6.2%; E4, 2.5%) and was comparable to rates in other published imaging series.

Intraventricular CNS lesions: A pictorial essay.

Intraventricular lesions of the central nervous system (CNS) can present a diagnostic challenge due to a range of differential diagnoses and radiological appearances. Both CT and MRI imaging findings, in combination with location and patient's age, can help limit the differentials. This pictorial essay presents the salient radiological features, location and demographics of the more common intraventricular lesions of the brain.

Part 1: MRI features of focal nodular hyperplasia with an emphasis on hepatobiliary contrast agents.

Focal nodular hyperplasia (FNH) is the second most common benign liver tumour and typically do not require any treatment. An accurate non-invasive diagnosis is therefore vital to avoid unnecessary intervention and to reassure patients. This article discusses the demographics and pathology of FNH and reviews the appearance of FNH at MRI using liver-specific contrast agents.

Part 2: MRI of hypervascular focal liver lesions using liver specific contrast agents.

Hypervascular liver lesions are frequently encountered and can be characterised by using hepatobiliary contrast agents at MRI examinations. The imaging characteristics of a variety of hypervascular liver lesions are presented with an emphasis on differentiating features.

Solid focal liver lesion characterisation with apparent diffusion coefficient ratios.

INTRODUCTION: Non-invasive characterisation of focal liver lesions using diffusion-weighted imaging (DWI) has been heavily investigated and has shown substantial overlap between benign and malignant lesions. We have calculated a ratio of lesion to normal liver to determine if it improves accuracy for correct categorisation. METHOD: All hepatic MRI studies performed between 1st April 2009 and 26th September 2011 were retrospectively reviewed. Patients with solid focal liver lesions in whom a diagnosis could be established and had lesions over 10 mm were included. Haemangiomas, cysts and patients with chronic liver disease were excluded. Apparent diffusion coefficient (ADC) values were calculated for each lesion and adjacent normal liver on breath hold DWI. RESULTS: Two hundred fifty-eight studies were performed and 206 were excluded leaving 52 scans and 58 lesions of which 47 were benign and 11 were malignant. The mean ADC value for benign lesions was 1196.6 (two standard deviations (2SD) = ±399.9) and of benign liver 1101.5 (2SD = ±329.8) with a ratio of benign lesion to benign liver of 1.1005 (2SD = ±0.3783). The mean ADC of malignant lesions was 1153.0 (2SD = ±604.9) and malignant liver of 1080.7 (2SD = ±533.4) giving a malignant lesion to malignant liver ratio of 1.0890 (2SD = ±0.4975). None of these results were statistically significant (all P > 0.5). CONCLUSION: DWI is unable to reliably differentiate solid benign lesions from solid malignant lesions.

Hybrid proximal surgery plus adjunctive retrograde endovascular repair in acute DeBakey type I dissection: superior outcomes to conventional surgical repair.

OBJECTIVE: The present study compared the outcomes between conventional surgery and the hybrid approach of proximal surgery with adjunctive retrograde descending aortic endografting plus distal bare metal stenting in acute DeBakey type I dissection. METHODS: From 2003 to 2011, 61 patients underwent surgical management for acute type A aortic dissection at our institution. Of these, 37 were DeBakey type I dissections: 18 patients (group 1) received conventional surgical repair alone, and 19 (group 2) underwent conventional hybrid surgery with adjunctive retrograde descending aortic stent grafting plus distal bare metal stenting. RESULTS: The patients' baseline characteristics were comparable, including the incidence of preoperative malperfusion syndromes (P = .23). The intraoperative and postoperative characteristics were similar, except 4 (22%) patients in group 1 (vs 0 in group 2) had ongoing malperfusion postoperatively (P = .04). Overall, hospital mortality was 11% (n = 2) for group 1 versus 5% (n = 1) for group 2. At a mean follow-up of 50 months, 4 (25%) subjects in group 1 required secondary thoracoabdominal aortic reintervention versus none in group 2 (P = .03). CONCLUSIONS: The use of adjunctive retrograde descending aortic endografting plus distal bare metal stenting during acute DeBakey type 1 dissection repair is a feasible method to enhance thoracoabdominal remodeling. This hybrid strategy improves perioperative outcomes and decreases late distal aortic complications compared with conventional surgical repair for acute DeBakey type I dissection. A prospective, multicenter study is warranted to definitively assess this promising new treatment paradigm.

Primary central nervous system lymphoma in immunocompetent patients: a retrospective review of MRI features.

INTRODUCTION: To define the features of primary central nervous system lymphoma (PCNSL) on MRI in immunocompetent patients. METHODS: A retrospective review of the authors' institutional database was performed to identify histologically proven cases of PCNSL. Images were retrieved and reviewed with respect to location, lesion number, size, signal intensity, enhancement characteristics, oedema and necrosis. RESULTS: Thirty-one cases of histologically proven PCNSL had available imaging. One patient was excluded due to immunosuppression. Of the 30 remaining cases, the average age was 65.5 years, and males and females were equally represented. A total of 68 lesions (average of 2.5 per patient) were identified. With diffusion-weighted imaging, all but two had restricted diffusion (40.3% mild and 55.6% marked) and all but one had enhancement (51.5% homogeneous, 42.6% heterogeneous and ring 4.4%). Most lesions were isointense to grey matter (75.8% on T2-weighted image (WI) and 82.5% on T1-WI). Oedema was mild in 43.4% and marked in 55.2%. Necrosis was seen in only five lesions (7.4%). On a per patient basis, 50% had bilateral lesions and 96.7% had lesions contacting a cerebrospinal fluid (CSF) surface. 16.7% of patients had posterior fossa involvement and 30% had lesions in the basal ganglia or thalami. CONCLUSION: The vast majority of cases of PCNSL in immunocompetent patients have lesions contacting a CSF surface, enhancement and restricted diffusion with no necrosis. These features should alert radiologists to the diagnosis of PCNSL.

Magnetic resonance features of primary central nervous system lymphoma in the immunocompetent patient: a pictorial essay.

Primary central nervous system lymphoma (PCNSL) is an uncommon but important variant of non-Hodgkin lymphoma and represents up to 6% of all primary central nervous system (CNS) malignancies. Recognition of this entity by radiologist on MRI may avoid unnecessary neurosurgical resection and redirect to biopsy. The pretreatment MRI of patients with biopsy proven PCNSL from the last 5 years at our institution was reviewed. Selected examples were used to construct a pictorial essay to illustrate some of the typical and atypical MR features of PCNSL. MRI of other CNS conditions with imaging similarities to PCNSL was included to demonstrate possible mimics. The typical features of PCNSL lymphoma are intra-axial homogenous single or multiple contrast enhancing lesions, with marked surrounding oedema and restricted diffusion, usually contacting a cerebrospinal fluid (CSF) surface. Necrosis, peripheral enhancement, haemorrhage or calcification are unusual and other diagnoses should be considered if any of these features are present. Potential mimics include high grade glioma, infarcts, metastatic disease, demyelination, abscess and secondary lymphoma. Careful assessment of the MR features and correlation with the clinical findings should enable the radiologists to raise the possibility of PCNSL and minimise the risk of unnecessary resection.

Combined proximal stent grafting plus distal bare metal stenting for management of aortic dissection: Superior to standard endovascular repair?

OBJECTIVES: The present study compared the outcomes between combined proximal descending aortic endografting plus distal bare metal stenting and conventional proximal descending aortic stent-graft repair in patients with type A and type B aortic dissection. METHODS: From January 2003 to December 2010, 63 patients underwent endovascular treatment for acute (type A, 24; type B, 21) and chronic (type B, 18) aortic dissection. Of these, 40 patients underwent proximal descending aortic endografting plus distal bare metal stenting (group 1), and 23 underwent proximal descending stent-graft repair alone (group 2). All patients with type A dissection underwent open surgical intervention plus adjunctive retrograde endovascular repair. RESULTS: The patients were comparable for baseline characteristics and treatment indicators, but more group 1 patients were active smokers (P = .03). The intraoperative characteristics were also similar, although 4 patients, all in group 2, developed malperfusion syndrome postoperatively (P = .02). The overall hospital mortality was 6%. At a mean follow-up of 49 months, 9 group 2 patients (43%) required unplanned secondary intervention compared with 4 in group 1 (11%; P = .007). Reintervention for thoracoabdominal aortic aneurysm or visceral ischemia was performed in 4 patients (19%) from group 2 (P = .03). Late aortic-related deaths occurred in 1 (5 %) and 2 (5%) patients in groups 1 and 2, respectively. CONCLUSIONS: Combined proximal descending aortic endografting plus distal bare metal stenting for aortic dissection provides favorable short-term outcomes and decreases late distal aortic complications compared with conventional endovascular repair. These results support a more widespread application of this approach. A prospective, randomized trial is needed before definite conclusions can be made.

Combined proximal endografting with distal bare-metal stenting for management of aortic dissection.

BACKGROUND: Established endovascular treatments for aortic dissection often result in incomplete aortic repair, potentially leading to late complications involving the distal aorta. To address the problems of incomplete true lumen reconstitution and late aneurysmal change, we report the midterm results of combined proximal endografting with distal true lumen bare-metal stenting (STABLE: Staged Total Aortic and Branch vesseL Endovascular reconstruction) in Stanford type A and B aortic dissection. METHODS: Between January 2003 and January 2010, 31 patients underwent staged total aortic and branch vessel endovascular reconstruction for management of acute (type A, 13; type B, 11) and chronic (type B, 7) aortic dissection. Proximal endografting was combined with bare-metal Z stent implantation in the distal true lumen. Patients with type A dissection underwent adjunctive treatment at operation. Computed tomography angiography was performed at baseline, 1 year, and annually thereafter to assess aortic remodelling. RESULTS: Primary technical success was 97%. Thirty-day rates of death, stroke, and permanent paraplegia/paresis were 3% (n=1), 0%, and 0%, respectively. Mean follow-up was 57.3 months (range, 5 to 100 months). Overall survival was 60% at 100 months. Aortic-specific survival was 93%. Four patients (13%) underwent device-related reintervention. One (3%) late aortic-related death occurred. Thoracic (p=0.64) and abdominal (p=0.14) aortic dimensions were stable. The true lumen index increased significantly at follow-up. CONCLUSIONS: Staged total aortic and branch vessel endovascular reconstruction is a feasible ancillary endovascular technique to address the problems of distal true lumen collapse, incomplete aortic remodelling, and late aneurysm formation in aortic dissection.

Positron emission tomography with selected mediastinoscopy compared to routine mediastinoscopy offers cost and clinical outcome benefits for pre-operative staging of non-small cell lung cancer.

PURPOSE: (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging is an important staging procedure in patients with non-small cell lung cancer (NSCLC). We aimed to demonstrate, through a decision tree model and the incorporation of real costs of each component, that routine FDG-PET imaging as a prelude to curative surgery will reduce requirements for routine mediastinoscopy and overall hospital costs. METHODS: A decision tree model comparing routine whole-body FDG-PET imaging to routine staging mediastinoscopy was used, with baseline variables of sensitivity, specificity and prevalence of non-operable and metastatic disease obtained from institutional data and a literature review. Costings for hospital admissions for mediastinoscopy and thoracotomy of actual patients with NSCLC were determined. The overall and average cost of managing patients was then calculated over a range of FDG-PET costs to derive projected cost savings to the community. RESULTS: The prevalence of histologically proven mediastinal involvement in patients with NSCLC presenting for surgical assessment at our institution is 20%, and the prevalence of distant metastatic disease is 6%. Based on literature review, the pooled sensitivity and specificity of FDG-PET for detection of mediastinal spread are 84% and 89% respectively, and for mediastinoscopy, 81% and 100%. The average cost of mediastinoscopy for NSCLC in our institution is 4,160 AUD, while that of thoracotomy is 15,642 AUD. The cost of an FDG-PET scan is estimated to be 1,500 AUD. Using these figures and the decision tree model, the average cost saving is 2,128 AUDper patient. CONCLUSION: Routine FDG-PET scanning with selective mediastinoscopy will save 2,128 AUD per patient and will potentially reduce inappropriate surgery. These cost savings remain robust over a wide range of disease prevalence and FDG-PET costs.