Infantile and juvenile neuronal ceroid lipofuscinosis (NCLs) are progressive neurodegenerative disorders of childhood with distinct ages of clinical onset, but with a similar pathological outcome. Infantile and juvenile NCL are inherited in an autosomal recessive manner due to mutations in the CLN1 and CLN3 genes, respectively. Recently developed Cln1-and Cln3-knockout mouse models share similarities in pathology with the respective human disease. Using oligonucleotide arrays we identi¢ed reproducible changes in gene expression in the brains of both 10-week-old Cln1-and Cln3-knockout mice as compared to wild-type controls, and con¢rmed changes in levels of several of the cognate proteins by immunoblotting. Despite the similarities in pathology, the two mutations a¡ect the expression of di¡erent, non-overlapping sets of genes. The possible signi¢cance of these changes and the pathological mechanisms underlying NCL diseases are discussed. ß

Gastrointestinal (GI) bleeding is a common potentially life-threatening medical condition frequently requiring multidisciplinary collaboration to reach the proper diagnosis and guide management. GI bleeding can be overt (eg, visible hemorrhage such as hematemesis, hematochezia, or melena) or occult (eg, positive fecal occult blood test or iron deficiency anemia). Upper GI bleeding, which originates proximal to the ligament of Treitz, is more common than lower GI bleeding, which arises distal to the ligament of Treitz. Small bowel bleeding accounts for 5-10% of GI bleeding cases commonly manifesting as obscure GI bleeding, where the source remains unknown after complete GI tract endoscopic and imaging evaluation. CT can aid in identifying the location and cause of bleeding and is an important complementary tool to endoscopy, nuclear medicine, and angiography in evaluating patients with GI bleeding. For radiologists, interpreting CT scans in patients with GI bleeding can be challenging owing to the large number of images and the diverse potential causes of bleeding. The purpose of this pictorial review by the Society of Abdominal Radiology GI Bleeding Disease-Focused Panel is to provide a practical resource for radiologists interpreting GI bleeding CT studies that reviews the proper GI bleeding terminology, the most common causes of GI bleeding, key patient history and risk factors, the optimal CT imaging technique, and guidelines for case interpretation and illustrates many common causes of GI bleeding. A CT reporting template is included to help generate radiology reports that can add value to patient care.

The purpose of this study is to evaluate the performance of a sequential multi-modality imaging algorithm for diagnosing acute appendicitis in pregnancy. This IRB-approved, HIPAA compliant study included 127 consecutive pregnant patients imaged for suspected appendicitis between October 2007 and May 2012; all patients initially underwent ultrasound (US) examination, followed by magnetic resonance imaging (MRI) if results of US were negative or equivocal. Computerized tomography (CT) was reserved for cases with inconclusive US and MRI results. The EMR was reviewed, recording results of imaging examinations and clinical outcomes. The diagnostic performance of this sequential multi-modality imaging algorithm was calculated with pathology correlation. Two (1.9 %) of the 127 US examinations reported suspected appendicitis; 125 (98.4 %) were inconclusive. Of the 125 patients with inconclusive US examinations, 103 underwent MRI, of which eight (6.2 %) demonstrated findings of acute appendicitis. Of the 103 patients that received MRI, nine (8.7 %) underwent CT. One patient had a CT performed directly after an inconclusive US exam. No additional cases of appendicitis were detected with CT. The sensitivity and specificity of US alone was 12.5 and 99.2 %, respectively; MRI was 100 and 93.6 %; the sequential multi-modality modality algorithm including US, CT, and MRI was 100 and 98.3 %. The diagnostic performance of this sequential multi-modality imaging algorithm for diagnosing acute appendicitis in pregnancy is high. Given the low yield of US, MRI should be considered the first-line imaging test. Although CT was employed in a small fraction of inconclusive MRI examinations, it still has a role in the diagnostic work-up of the pregnant patient with suspected appendicitis.

In patients with body mass index greater than 25 presenting to the ED with acute abdominal pain, CT examinations can be acquired without oral contrast without compromising the clinical efficacy of CT.