Feasibility of low-dose CT with model-based iterative image reconstruction in follow-up of patients with testicular cancer.

PURPOSE: We examine the performance of pure model-based iterative reconstruction with reduced-dose CT in follow-up of patients with early-stage testicular cancer. METHODS: Sixteen patients (mean age 35.6 ± 7.4 years) with stage I or II testicular cancer underwent conventional dose (CD) and low-dose (LD) CT acquisition during CT surveillance. LD data was reconstructed with model-based iterative reconstruction (LD-MBIR). Datasets were objectively and subjectively analysed at 8 anatomical levels. Two blinded clinical reads were compared to gold-standard assessment for diagnostic accuracy. RESULTS: Mean radiation dose reduction of 67.1% was recorded. Mean dose measurements for LD-MBIR were: thorax - 66 ± 11 mGy cm (DLP), 1.0 ± 0.2 mSv (ED), 2.0 ± 0.4 mGy (SSDE); abdominopelvic - 128 ± 38 mGy cm (DLP), 1.9 ± 0.6 mSv (ED), 3.0 ± 0.6 mGy (SSDE). Objective noise and signal-to-noise ratio values were comparable between the CD and LD-MBIR images. LD-MBIR images were superior (p < 0.001) with regard to subjective noise, streak artefact, 2-plane contrast resolution, 2-plane spatial resolution and diagnostic acceptability. All patients were correctly categorised as positive, indeterminate or negative for metastatic disease by 2 readers on LD-MBIR and CD datasets. CONCLUSIONS: MBIR facilitated a 67% reduction in radiation dose whilst producing images that were comparable or superior to conventional dose studies without loss of diagnostic utility.

Reduction of guide needle streak artifact in CT-guided biopsy.

PURPOSE: Computed tomography (CT)-guided core needle biopsy (CNB) can be affected by streak artifact obscuring the needle tip. This study investigates factors that influence the occurrence and severity of streak artifact during CNB. MATERIALS AND METHODS: Eight coaxial guide needles of two sizes from two manufacturers with and without stylets were imaged in a CT phantom, with CT reconstructed with adaptive statistical iterative reconstruction and filtered back projection. CNB-related streak artifact was quantified with profile analysis in an image-processing program. Differences between maximum attenuation at the needle tip and minimum attenuation in the streak artifact were compared for each variable. Diagnostic acceptability and streak artifact were subjectively assessed on each phantom image and on 40 clinical CNB procedures by three independent blinded reviewers following training case review. RESULTS: Artifact was significantly less with the central stylet removed versus in situ (median, 1,145 HU vs 3,390 HU; P < .001) for all needles, and less for 19-gauge needles versus 17-gauge needles (median, 1,334 HU vs 2,780 HU, respectively; P = .006). There were no differences based on manufacturer (P = .906) or reconstruction algorithm (P = .524). Independent reviews found that streak artifact was significantly reduced when the central stylet was removed (κ = 0.875-1.0; P < .001), and needle tip position was better in cases in which the stylet was removed (κ = 0.231-0.711; P < .001). CONCLUSIONS: Streak artifact can be reduced and needle tip visualization improved by confirming final biopsy needle position with the central stylet removed on CT and using smaller-gauge guide needles.

New-onset mediastinal and central nervous system sarcoidosis in a patient with metastatic melanoma undergoing CTLA4 monoclonal antibody treatment.

BACKGROUND: Ipilimumab, a cytotoxic monoclonal antibody that inhibits cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), has been established as an effective therapy in the management of advanced melanoma. Immune-mediated adverse events are a common side effect. CASE REPORT: A 37-year-old male patient was diagnosed with nodal and osseous metastatic melanoma 15 months after the initial surgical treatment for lower limb melanoma. Therapy with the anti-CTLA-4 antibody, ipilimumab, was started. Follow-up staging imaging after treatment initiation showed symmetrical bihilar adenopathy. Transbronchial biopsy showed sarcoidosis. The patient had associated systemic symptoms of fatigue, joint pains, anorexia and weight loss. Brain magnetic resonance imaging (MRI), which was performed for the investigation of headaches, showed abnormal enhancing tissue in the sella turcica and adjacent to the pituitary infundibulum, consistent with neurosarcoidosis. The condition was successfully treated with corticosteroids. CONCLUSIONS: We report a case of immunotherapy-induced mediastinal/hilar sarcoidosis, with pituitary involvement, mimicking tumour progression. This highlights the need for awareness amongst radiologists and oncologists of the mechanism of action and potential side effects of new immunotherapies.

Gastrointestinal stromal tumors (GIST): lesser known facts.

In an era of molecular targeted therapy, patients with advanced gastrointestinal stromal tumor (GIST) are living longer and are often followed with imaging. Therefore, it is important for the radiologists to be aware of the atypical subtypes of GIST, implications of molecular makeup, its behavior, and the uncommon metastatic sites. The aim of this pictorial review is to illustrate the lesser-known aspects of GIST including histological and molecular classifications, syndromes associated with GIST, and uncommon metastatic sites.

Positron emission tomography/computed tomography imaging in Merkel cell carcinoma: a study of 270 scans in 97 patients at the Dana-Farber/Brigham and Women's Cancer Center.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare and lethal cutaneous neuroendocrine carcinoma. Imaging is crucial for accurate staging, which remains a strong predictor of survival, as well as earlier detection of recurrence and progression, which are common despite aggressive management. There is no consensus on the role of initial and subsequent imaging for MCC. OBJECTIVE: We sought to evaluate the use of 2-fluoro-[(18)F]-deoxy-2-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in the management of MCC. METHODS: In all, 270 FDG-PET/CT studies were performed in 97 patients with pathology-proven MCC at the Dana-Farber/Brigham and Women's Cancer Center, Boston, Mass, from August 2003 to December 2010. RESULTS: FDG-PET/CT scans were obtained as part of the initial (61 scans in 61 patients) and subsequent (209 scans in 79 patients) treatment strategies. MCCs were FDG-avid with a mean maximum standardized uptake value of primary lesions of 6.5 (range 1.3-12.9) and a mean maximum standardized uptake value of regional and distant metastases of 7.2 (range 1.5-9.9). FDG-PET/CT upstaged 16% of patients who underwent baseline scans. FDG-PET/CT studies showed that bone and bone-marrow metastases were more common than previously reported, and were often undetected by CT. LIMITATIONS: Our study is limited by its retrospective design, and potential referral bias associated with a tertiary care center. CONCLUSIONS: FDG-PET/CT performed as part of the initial management strategy tended to upstage patients with more advanced disease. FDG-PET/CT performed as part of the subsequent treatment strategy identified metastatic disease, particularly in bone/bone marrow, which was not seen on CT. FDG-PET/CT imaging is a valuable staging and restaging tool in MCC management.

Evaluation of the efficacy and safety of percutaneous biopsy of lung.

INTRODUCTION: Percutanous needle biopsy of the lung (PNBL), under image guidance, has established itself as a safe and effective minimally-invasive method of obtaining a tissue diagnosis of pulmonary lesions, for selected patients with suspected pathologic processes. The purpose of this study was to evaluate the diagnostic yield and safety of percutaneous core biopsy of the lung (PCBL) without Fine Needle Aspiration Biopsy (FNAB), with specific attention to potential risk factors that may predict post-biopsy pneumothorax. MATERIALS AND METHODS: A retrospective analysis of 75 consecutive PCBL procedures between January 2006 to March 2008 involving 72 patients with a documented pulmonary nodule or mass lesion on CT scan of Thorax. The study population included 38 males (52.8%) and 34 females (47.2%) aged 20-85 years (mean age 63.6 years). A co-axial cutting system with a 19-gauge outer needle and a 20-gauge inner automated cutting needle (Temno, Allegiance Healthcare Corporation, Ohio, USA) was used in all patients. RESULTS: Lesions varied in size from 0.7cm to 10.7cm (mean maximum trans-axial diameter 3.1cm). The mean number of core biopsy samples obtained was 3.1 (range 1-5). Of the 75 PCBL procedures, 71 yielded specimens adequate for histopathologic evaluation, consistent with a technical success rate of 95%. Malignancy was detected in 48 specimens (64%) and benign diagnoses were identified in 23 specimens (31%). As mentioned, 4 specimens (5%) were nondiagnostic. The most common biopsy-induced complication was pneumothorax, occurring in 15 patients (20%), with 4 (5.3%) requiring thoracostomy tube placement. CONCLUSION: PCBL without FNAB, under CT fluoroscopy guidance, has an excellent diagnostic accuracy in obtaining a conclusive histologic diagnosis of thoracic lesions and is comparable to FNAB in terms of safety and rates of occurence of complications.

Uterine sarcomas: then and now.

OBJECTIVE: The purpose of this article is to provide an updated review of uterine sarcomas. The traditionally described neoplasms are reviewed as well as several recently characterized entities in terms of their imaging and clinical aspects. We attempt to provide a longitudinal imaging overview, from initial presentation to follow-up. Imaging features are also described of response to traditional therapeutic agents and newer targeted agents. CONCLUSION: A greater understanding of the pathogenesis has improved our ability to image and treat uterine sarcomas, both at initial staging and on follow-up. Targeted therapy is assuming an increasingly important role in the management of these lesions. It is imperative for radiologists to be aware of response characteristics and potential complications of these agents as well as conventional chemotherapeutic agents.

Investigation of the role of computed tomography as an adjunct to autopsy in the evaluation of stillbirth.

INTRODUCTION: The number of parents agreeing to autopsy following stillbirth is declining, which has undermined clinicians' ability to assess causes of intrauterine death and can impact counselling regarding recurrence. Post-mortem radiological imaging is a potential alternative method of investigating perinatal loss. The aim of this study was to assess the role of multi-detector computed tomography (MDCT) in the investigation of stillbirth. STUDY DESIGN: Following ethical approval and written consent, parents were offered MDCT of the stillborn infant. MDCT was performed with 3D reconstruction, and images were analysed for image quality, anthropomorphic measurements and pathologic findings. Body part and organ-specific measurements were performed; including head, chest and abdominal circumferences, and muscle and liver mass was also measured. Findings were correlated with obstetric history, post-mortem skeletal survey (plain radiography), and formal autopsy. RESULTS: Fourteen third-trimester stillborn infants were scanned. Image quality was moderate to excellent for most body structures. CT was better than plain radiography for imaging skeletal structures and large solid organs and demonstrated a range of pathologies including renal vein thrombosis, mesenteric calcification and skeletal hyperostosis that were not seen on plain radiographs. MDCT did not overlook autopsy findings and provided some additional information. CONCLUSION: This study confirms the feasibility of MDCT in the investigation of third trimester stillbirth. MDCT image quality is acceptable and the examination can demonstrate a range of anatomic and pathologic findings. Initially, its value may be as an important adjunct to conventional autopsy.

Extrahepatic spread of hepatocellular carcinoma: spectrum of imaging findings.

OBJECTIVE: The purpose of this article is to describe the imaging findings of extrahepatic spread of hepatocellular carcinoma (HCC). CONCLUSION: Detecting extrahepatic metastases in HCC is critical in determining the optimal treatment plan for patients. Identifying the presence of extrahepatic metastases in patients with advanced disease may eliminate unnecessary surgery, such as liver transplantation or partial hepatic resection, and help direct the appropriate therapy.

Radiologic aspects of immune-related tumor response criteria and patterns of immune-related adverse events in patients undergoing ipilimumab therapy.

OBJECTIVE: The objective of this article is to illustrate examples of radiologic immune-related response criteria and toxicity in patients with advanced melanoma treated with the immunotherapeutic agent ipilimumab. CONCLUSION: Novel immune-related tumor response criteria should be applied to patients undergoing therapy with ipilimumab for advanced melanoma. Ipilimumab also produces a spectrum of immune-related adverse effects that can be recognized radiologically.

Imaging of liposarcoma: classification, patterns of tumor recurrence, and response to treatment.

OBJECTIVE: The purpose of this study was to illustrate the subtypes of liposarcoma (LPS) and the significance of the nonlipomatous tumor components using multiple imaging modalities. CONCLUSION: The subtypes of LPS with greater nonlipomatous soft-tissue components on imaging studies tend to show less differentiation and are usually more aggressive both histologically and clinically. Imaging plays an important role in the diagnosis, surveillance, and response assessment of LPS.

Rapid progression of combined hepatocellular carcinoma and cholangiocarcinoma.

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CC) is a rare entity comprising 1-14.2% of all primary liver carcinomas. In this report, we present a case of rapid progression of cHCC-CC, a rare tumor in a 77-year-old Caucasian male patient with hepatitis B-induced cirrhosis, moderately elevated alpha fetoprotein, and imaging and pathologic features of a mixed liver tumor. There was no evidence of metastatic disease in the chest, abdomen or pelvis by computed tomography (CT) scan at the time of diagnosis. Needle biopsy of the segment 8 lesion revealed two discrete histologic components to the tumor: well-differentiated HCC and poorly differentiated adenocarcinoma, consistent with intrahepatic CC.The patient rapidly developed metastatic disease after initial local therapy with hepatic arterial chemoembolization and percutaneous cryoablation, dying within 5 months of diagnosis. Radiofrequency ablation, cryoablation and radioembolization with yttrium-90 microspheres remain possible treatment strategies for patients with cHCC-CC unable to undergo surgical resection. The diagnosis and treatment of cHCC-CC can be challenging due to clinical, imaging and histological features that overlap with pure HCC and CC.

Association between preoperative magnetic resonance imaging, pain intensity and quantitative sensory testing in patients awaiting lumbar diskectomy.

INTRODUCTION: Magnetic resonance imaging (MRI) offers important information regarding the morphology, location and size of a herniated disc, which influences the decision to offer lumbar diskectomy (LD). This study aims to examine the association between clinical neurophysiologic indices including pain intensity and quantitative sensory testing (QST), and the degree of lumbar nerve root compromise depicted on magnetic resonance (MR) in patients awaiting LD. METHODS: With institutional ethical approval, 16 patients (American Society of Anaesthesiologists Grades I-II, 18-65 years) with radicular pain for greater than 3 months undergoing elective LD were studied. Preoperative pain was assessed using (i) a visual analogue scale measuring pain intensity at rest and with movement and (ii) by quantifying pain sensory thresholds (St), pain perception thresholds (PPt), and pain tolerance threshold (PTt) using QST. MR images were independently graded by two radiologists blinded to the clinical data using the Pfirrmann grading system. Statistical analyses using Student's t-tests and Pearson's correlation were preformed where appropriate. RESULTS: This study showed that: (i) findings on MR imaging corresponded with the symptomatic side and distribution of the pain; (ii) the degree of nerve root compromise, detected on MRI correlated with increased pain intensity at rest; and (iii) QST identified a trend towards higher St, PPt and PTt in patients with higher Pfirrmann grades. CONCLUSIONS: The Pfirrmann grading system of nerve root compromise may be clinically useful preoperatively as a method of identifying individuals who would benefit most from LD. However, additional studies with greater patient numbers and longer follow-up are required to definitively confirm the findings of this study.

Unexpected late radiation neurotoxicity following bevacizumab use: a case series.

The purpose of this case series is to report the unexpected occurrence of four cases of late radiation-induced neurotoxicity with bevacizumab use following radiotherapy to the CNS. We retrospectively reviewed the case records of four patients, three with glioblastoma and one with bone metastases secondary to metastatic breast cancer, who were treated with radiotherapy and developed late radiation-induced neurotoxicity following bevacizumab use. Three cases of optic neuropathy in glioblastoma patients and a single case of Brown-Séquard syndrome in the thoracic spine of a patient with metastatic breast cancer are reported. We hypothesize that bevacizumab use following radiotherapy to the CNS may inhibit vascular endothelial growth factor-dependent repair of normal neural tissue, and thus may increase the risk of late radiation neurotoxicity. Phase III data on the safety and efficacy of bevacizumab use with radiation in the setting of glioblastoma is awaited.

The role of imaging in the investigation of painless hematuria in adults.

The radiologic investigation of asymptomatic hematuria has changed significantly due to the introduction of new imaging modalities and innovative techniques, such as computed tomography urogaphy, which allows a comprehensive evaluation of the entire urinary tract in a single study. There is still a role for "older" imaging modalities, such as intravenous urography and ultrasound, and their use is still advocated in younger patients with a lower risk of malignancy to minimize radiation dose. Combined modality imaging can also be useful for characterization of lesions. Guidelines have recently been published for the radiologic investigation of hematuria; these are discussed in this article.