Prevalence of Appendicoliths Detected at CT in Adults With Suspected Appendicitis.

OBJECTIVE. With heightened interest in nonoperative antibiotic management of uncomplicated appendicitis, appendicoliths become a more relevant issue, and because of higher failure rates their presence may be considered a contraindication. The purpose of this study was to investigate the prevalence of appendicoliths at CT in adults with suspected appendicitis. MATERIALS AND METHODS. Among adults undergoing MDCT for suspected appendicitis, 248 patients (134 women, 114 men; mean age, 35.2 years) consecutively registered over a 3-year period constituted a cohort with surgically proven appendicitis. A cohort of 248 patients (175 women, 73 men; mean age, 37.7 years) without appendicitis consecutively registered over a 1-year period served as control subjects. CT examinations were reviewed for the presence, size, and attenuation of appendicoliths and whether the appendicoliths were obstructing. In the cohort with appendicitis, degree of inflammation (3-point scale) and likelihood for perforation (5-point scale) were scored. RESULTS. The prevalence of appendicoliths at CT was 38.7% (96/248) among patients with appendicitis and 4.4% (11/248) among control subjects (p < .001). Among the 96 patients with appendicitis who had visible appendicoliths, mean width, length, and maximum attenuation of the dominant appendicolith were 6.0 mm, 8.2 mm, and 313 HU, respectively. In 70.8% (68/96) of patients appendicoliths were obstructing, and 32.3% (31/96) of patients had more than one appendicolith. Inflammation (1.75 vs 1.43) and likelihood of perforation (2.07 vs 1.51) (p < .05) scores were higher among patients with appendicitis who had appendicoliths. Extraluminal appendicoliths were seen in five cases of perforated appendicitis. CONCLUSION. Appendicoliths were identified at CT in nearly 40% of adults with proven appendicitis, compared with slightly more than 4% of those without appendicitis, and were associated with increased inflammation and risk of perforation.

Stump Appendicitis: Clinical and CT Findings.

OBJECTIVE. Recurrent inflammation of the appendiceal stump after appendectomy is rare; published case series have included no more than six patients. The purpose of this study was to report the clinical and CT findings in a larger original series. MATERIALS AND METHODS. A combined PACS and electronic medical record search identified the cases of 14 patients (nine men, five women; mean age, 42.8 years) with a confident diagnosis of stump appendicitis evaluated at CT. In seven cases, CT images obtained at the initial presentation of appendicitis were available for review. Relevant clinical and CT findings were reviewed by three abdominal radiologists in consensus. RESULTS. The mean time interval between initial appendectomy and stump appendicitis was 5.1 years (range, 5 weeks-17.5 years); seven cases occurred within 1 year of appendectomy. Ten (71%) of initial appendectomies were performed by a laparoscopic approach. CT showed the mean appendiceal stump length was 3.2 cm (range, 1.3-7.0 cm); residual stump length measured 2 cm or longer in all but one case. Appendicoliths were identified at the stump in seven (50%) cases; the mean diameter was 0.9 cm and mean maximal attenuation, 247 HU. Extensive inflammatory changes surrounded the appendiceal stump at CT in all cases, including peristump abscess in four (29%) cases. Seven of the 14 patients (50%) went on to open surgical management with either remnant appendectomy or partial ileocecectomy. CONCLUSION. Stump appendicitis has a characteristic CT appearance and may occur within the first year after appendectomy or many years later. A long (≥ 2 cm) appendiceal stump from laparoscopic appendectomy and retained appendicolith may predispose adult patients to recurrent obstruction and inflammation.

MRI Evaluation of the Response of Rectal Cancer to Neoadjuvant Chemoradiation Therapy.

MRI plays a critical role in the staging and restaging of rectal cancer. Although newly diagnosed early-stage rectal cancers may immediately be amenable to surgical resection, patients with advanced disease first undergo neoadjuvant therapy that consists of a combination of chemotherapy and radiation therapy. Evaluation of rectal cancer after neoadjuvant therapy is best performed with MRI, given its superior soft-tissue contrast and its ability to allow multiplanar imaging and functional evaluation. In this setting, MRI allows accurate evaluation of primary tumor staging, which is determined on the basis of the depth of invasion within and through the rectal wall and the involvement of adjacent organs. MRI can also be used to evaluate posttreatment morphologic components within the tumors, including fibrosis and mucinous changes that have been shown to correlate with the response to treatment. Additional features such as the circumferential resection margin and extramural vascular invasion-factors shown to affect prognosis and local recurrence-are also assessed before and after therapy. Functional assessment with diffusion-weighted MRI and perfusion MRI plays a role in predicting tumor aggressiveness and the likelihood of response to treatment, as well as the extent of residual tumor after therapy. Lymph node staging is also performed at MRI, with assessment of not only lymph node size but also the internal architecture and signal intensity characteristics. ©RSNA, 2019 See discussion on this article by Wasnik and Al-Hawary .

Development and validation of sensitive liquid chromatography/tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue.

A liquid chromatography-tandem mass spectrometry method for quantification of bendamustine in mouse brain tissue was developed and fully validated. Methanol was used to precipitate proteins in brain tissue. Bendamustine and internal standard (chlorambucil) were separated with reverse-phase chromatography on a C-18 column with a gradient of water and 95% methanol in 0.1% formic acid. Positive mode electrospray ionization was applied with selected reaction monitoring to achieve 5 ng/ml lower limits of quantitation in mouse brain tissue. The calibration curve for bendamustine in mouse brain was linear between 5 and 2000 ng/ml. The within- and between-batch accuracy and precision of the assay were within 15% at 10, 100 and 1000 ng/ml. The recovery and matrix effect of bendamustine in mouse brain tissue ranged from 41.1% to 51.6% and 107.4% to 110.3%, respectively. The validated method was then applied to quantitate bendamustine in an animal study. Results indicate the assay can be applied to evaluate bendamustine disposition in mouse brain tissue. This assay will be applied in the future to detect and quantify bendamustine in human brain tissue samples.