Conventional and Advanced Imaging Techniques in Post-treatment Glioma Imaging.

Despite decades of advancement in the diagnosis and therapy of gliomas, the most malignant primary brain tumors, the overall survival rate is still dismal, and their post-treatment imaging appearance remains very challenging to interpret. Since the limitations of conventional magnetic resonance imaging (MRI) in the distinction between recurrence and treatment effect have been recognized, a variety of advanced MR and functional imaging techniques including diffusion-weighted imaging (DWI), diffusion tensor imaging (DTI), perfusion-weighted imaging (PWI), MR spectroscopy (MRS), as well as a variety of radiotracers for single photon emission computed tomography (SPECT) and positron emission tomography (PET) have been investigated for this indication along with voxel-based and more quantitative analytical methods in recent years. Machine learning and radiomics approaches in recent years have shown promise in distinguishing between recurrence and treatment effect as well as improving prognostication in a malignancy with a very short life expectancy. This review provides a comprehensive overview of the conventional and advanced imaging techniques with the potential to differentiate recurrence from treatment effect and includes updates in the state-of-the-art in advanced imaging with a brief overview of emerging experimental techniques. A series of representative cases are provided to illustrate the synthesis of conventional and advanced imaging with the clinical context which informs the radiologic evaluation of gliomas in the post-treatment setting.

A Case-Based Review of Cerebral Venous Infarcts With Perfusion Imaging and Comparison to Arterial Ischemic Stroke.

Cerebral venous thrombosis (CVT) and cerebral venous infarcts (CVI) are diagnostic dilemmas secondary to their rarity, non-specific symptomatology at presentation, and variable imaging features. Despite its relatively infrequence, CVT is particularly prevalent in the younger adult population and is a potentially life-threatening disease with devastating neurological complications if not addressed in a timely manner. However, when treated promptly, CVT has the potential for a more reversible course and favorable prognosis than arterial ischemic strokes (AIS). The pathophysiology of CVI is distinct from that of AIS and is closely related to its potentially reversible nature. Familiarity with the conventional and variant venous anatomy, as well as the temporal evolution of imaging findings, is crucial in establishing diagnostic confidence. The use of MR perfusion imaging (MRP) and arterial spin-labeling (ASL) can potentially aid in the diagnosis of CVT/CVI via characterization of cerebral blood flow. The presence and extent of a cerebral perfusion deficit on either CT or MRI may play a role in clinical outcomes for patients with CVT, although future larger studies must be performed. This review presents a case-based overview focusing on the classic imaging characteristics of CVT and CVI in conjunction with bolus MRP and ASL findings in the adult population.

Simultaneous 111In-WBC and 99mTc-SC SPECT/CT Clearly Delineates Infection Sites.

A 22-year-old man sustained a complex left ankle fracture following a motor vehicle collision and underwent external and internal fixation with transfixation-pinning. Several weeks after surgery, the patient presented with clinical concerning for infection at the fracture sites. Initial radiographic evaluation of the left lower extremity showed no evidence of osteomyelitis. The patient underwent SPECT/CT with a novel imaging protocol, using simultaneous acquisition of 111In-WBC and 99mTc- SC SPECT/CT, which clearly delineated the infection sites along the orthopedic hardware track and adjacent soft tissues. This new combined SPECT/CT protocol offers advantages of shorter scanning time, easy patient positioning, expedited diagnostic workup, and more accurate localization of infection sites compared to the conventional protocol of separately acquiring 111In-WBC and 99mTc- SC SPECT/CT images.

Abscess-Fistula Complexes: A Systematic Approach for Percutaneous Catheter Management.

PURPOSE: To describe a systematic catheter management approach for treatment of abscesses with enteric fistulae by abscess evacuation and selective fistula tract cannulation in a series of patients with postprocedural abscess-fistula complexes. MATERIALS AND METHODS: This single-center retrospective study included 27 patients (17 male; mean age, 51.3 y) who underwent percutaneous drainage of postprocedural abscess-fistula complexes from January 2005 to September 2013. There were 15 low-output and 12 high-output fistulae. Intra-abdominal abscesses were evacuated by percutaneous drainage. Multiple catheters were used for collections with viscous fluid or size ≥ 6 cm in diameter. High-output fistulae and recurrent low-output fistulae had additional catheter cannulation of the enteric hole to facilitate the creation of a controlled enterocutaneous tract. There was no preexisting cutaneous tract before catheter insertion in 23 fistulae. RESULTS: Abscess-fistula complex resolution occurred in 24 patients (88.9%). Of the 3 cases of failure, 2 patients required surgical repair of the fistula, and 1 patient died. Mean number of drainage procedures was 7.0, and mean catheter duration was 76.1 days. There was no significant difference in catheter duration of low-output and high-output abscess-fistula complexes (P = .34); however, high-output patients underwent significantly more procedures (9.1 vs 6.1, P = .025). There were 15 fistulae that were cannulated (11 high-output and 4 low-output fistulae). Cannulated abscess-fistula complexes had significantly longer catheter duration (102.5 d vs 53.2 d, P = .04) and underwent significantly more procedures (8.4 vs 5.4, P = .04). CONCLUSIONS: The catheter management strategy was successful in resolving most abscess-fistula complexes in this series.