Frank Earnest

Colonic Perforation at CT Colonography in a Patient Without Known Colonic Disease

2Department of Radiology, Mayo Clinic Rochester, Mayo East 2-B, 200 First St. SW, Rochester, MN 55905. Address correspondence to J. G. Fletcher. T colonography, or virtual colonoscopy, is now routinely used as a full structural examination of the colorectum following incomplete endoscopy [1] and in patients with elevated risk for complications during endoscopy or with aversion to endoscopy. CT colonography has demonstrated performance on par with optical colonoscopy in the screening of asymptomatic patients for adenomatous polyps in some hands [2] and has performed superiorly compared with nonendoscopic alternatives [3]. Optimal colonic inflation is essential to a high-quality CT colonography examination. Given the speed of image acquisition and reconstruction of MDCT scanners, patients must tolerate maximum inflation for only a few seconds, as opposed to endoscopy and barium enema, in which the colon remains inflated for much longer periods of time. Nevertheless, colonic insufflation is known to result in perforation, ranging from approximately 0.004–0.01% of cases for double contrast barium enema [4, 5] to 0.07–0.19% of cases for colonoscopy [6, 7]. To date, thousands of patients have undergone CT colonography without complications. Two cases of colonic perforation at CT have recently been reported in patients with known colonic disease [8, 9]. We report a case of perforation following CT colonography in a patient without known colonic disease.

Full recovery after acute hemorrhagic leukoencephalitis (Hurst's disease).

Sirs: Acute hemorrhagic leukoencephalitis (Hurst’s disease) is a rare catastrophic demyelinating disease often preceded by a mundane respiratory tract infection [2]. Antemortem diagnosis is uncommon, and the disorder remains misdiagnosed as viral encephalitis even in the modern era of computed tomography [6]. Death from brain edema is common within 1 week of onset of neurological symptoms, but patients have survived when treated with various combinations of corticosteroids, immunoglobulin, and cyclophosphamide, with most improvement after plasma exchange [3]. Occasionally these survivors have no obvious neurological sequelae, but comprehensive neuropsychometric testing has not been reported in follow-up [4, 5, 7]. We report a patient with Hurst’s disease and full recovery with corticosteroids additionally documented by serial magnetic resonance imaging (MRI) and neuropsychometric testing. A 34-year-old businessman was admitted to his local hospital in the United Arab Emirates after a generalized tonic-clonic seizure which was preceded by right arm rhythmic activity. Several weeks prior he had been treated for oral thrush with miconazole, presumed to be secondary to triple drug therapy for Helicobacter pylori infection (with Prilosec, clarithromycin, metronidazole). He rapidly progressed to status epilepticus and was treated with diazepam (Valium), phenytoin, and acyclovir. He was subsequently treated with 8 mg dexamethasone every 8 h for 6 days. Examination was limited due to sedation, but he did not withdraw to pain. His pupils were symmetric and responsive to light, oculocephalic responses were intact, deep tendon reflexes were brisk, and a left Babinski sign was apparent. MRI on admission showed hyperintense regions involving the subcortical, frontal and temporal, parietal region, and subacute hemorrhage in right basal ganglia (Fig. 1). CSF contained protein 125 mg/dl, glucose 52 mg/dl (simultaneous measurement of blood glucose was 115 mg/dl), white cell count of 64 cells μl, red blood cells of 124 μl, 70% lymphocytes, 10% neutrophils, and 20% macrophages. Gram stain, India ink, and acid-fast bacilli staining were all negative as was a polymerase chain reaction for herpes simplex. Viral, fungal, and bacterial cultures were negative. Serology for human immunodeficiency virus, cytomegalovirus, Epstein-Barr virus, herpes simplex I and II, Brucella, and Borrelia were negative for acute inLETTER TO THE EDITORS

Evaluation of irreversible compression of digitized posterior-anterior chest radiographs

The purpose of this article is to assess lossy image compression of digitized chest radiographs using radiologist assessment of anatomic structures and numerical measurements of image accuracy. Forty posterior-anterior (PA) chest radiographs were digitized and compressed using an irreversible wavelet technique at 10, 20, 40, and 80∶1. These were presented in a blinded fashion with an uncompressed image for A-B comparison of 11 anatomic structures as well as overall quality assessments. Mean error, root-mean square (RMS) error, maximum pixel error, and number of pixels within 1% of original value were also computed for compression ratios from 5∶1 to 80∶1. We found that at low compression (10∶1) there was a slight preference for compressed images. There was no significant difference at 20∶1 and 40∶1. There was a slight preference on some structures for the original compared with 80∶1 compressed images. Numerical measures showed high image faithfulness, both in terms of number of pixels that were within 1% of their original value, and by the average error for all pixels. Our findings suggest that lossy compression at 40∶1 or more can be used without perceptible loss in the representation of anatomic structures. On this finding, we will do a receiver-operator characteristic (ROC) analysis of nodule detection in lossy compressed images using 40∶1 compression.

Adult Intussusception: Presentation, Management, and Outcomes of 148 Patients

BACKGROUND Intussusception is a predominantly pediatric diagnosis that is not well characterized among adults. Undiagnosed cases can result in significant morbidity, making early recognition important for clinicians. STUDY OBJECTIVES We describe the presentation, clinical management, disposition, and outcome of adult patients diagnosed with intussusception during a 13-year period. METHODS A retrospective study of consecutive adult patients diagnosed with intussusception at a tertiary academic center was carried out from 1996 to 2008. Cases were identified using International Classification of Diseases, 9(th) Revision codes and a document search engine. Data were abstracted in duplicate by two independent authors. RESULTS Among 148 patients included in the study, the most common symptoms at presentation were abdominal pain (72%), nausea (49%), and vomiting (36%). Twenty percent were asymptomatic. Sixty percent of cases had an identifiable lead point. Patients presenting to the emergency department (ED) (31%) had higher rates of abdominal pain (relative risk [RR] 5.7) and vomiting (RR 3.4), and were more likely to undergo surgical intervention (RR 1.8) than patients diagnosed elsewhere. There were 77 patients who underwent surgery within 1 month; patients presenting with abdominal pain (RR 2.2), nausea (RR 1.7), vomiting (RR 1.4), and bloody stool (RR 1.9) were more likely to undergo surgery. CONCLUSIONS Adult intussusception commonly presents with abdominal pain, nausea, and vomiting; however, approximately 20% of cases are asymptomatic and seem to be diagnosed by incidental radiologic findings. Patients presenting to an ED with intussusception due to a mass as a lead point or in an ileocolonic location are likely to undergo surgical intervention.