Isolated recto-sigmoid colitis: a new imaging pattern of ipilimumab-associated colitis.

PURPOSE: The purpose of this study is to describe typical CT findings and distinct imaging patterns of ipilimumab-associated colitis in immunotherapeutic treatment of melanoma. MATERIALS AND METHODS: This HIPAA-compliant retrospective study included 86 patients with melanoma imaged with CT or PET/CT of the abdomen and pelvis during or shortly after administration of ipilimumab. Twelve of 86 patients (14%) developed symptoms of colitis and underwent CT imaging of the abdomen and pelvis while symptomatic. Two radiologists reviewed CT images to evaluate for the presence of CT findings of colitis including mesenteric vessel engorgement, pericolonic inflammatory change, hyperenhancement of colonic mucosa, colonic wall thickening, fluid-filled colonic distension, pneumoperitoneum, pneumatosis, and diverticulosis in the inflamed segment of colon. One nuclear medicine radiologist reviewed PET images for abnormally increased FDG uptake in the colon. The diagnosis of ipilimumab-associated colitis was made based on clinical presentation, imaging findings, and laboratory data. RESULTS: Common CT findings of ipilimumab-associated colitis included colonic mucosal hyperenhancement (10/12 [83%]), mesenteric vessel engorgement (9/12 [75.0%]), colonic wall thickening (9/12 [75%]), and pericolonic fat stranding (2/12 [16%]). No patient developed pneumatosis or pneumoperitoneum. Diffuse colitis was present in 4/12 (33%) patients. Segmental colitis with associated diverticulosis (was present in 2/12 (17%) patients). A third pattern, isolated recto-sigmoid colitis without diverticulosis, was observed in 6/12 (50%) patients. All patients with colitis demonstrated recto-sigmoid involvement. CONCLUSIONS: A third radiologic pattern of ipilimumab-associated colitis was observed in this study: isolated recto-sigmoid colitis without diverticulosis. All patterns of ipilimumab-associated colitis include recto-sigmoid involvement.

Virtual Monochromatic Images from Dual-Energy Multidetector CT: Variance in CT Numbers from the Same Lesion between Single-Source Projection-based and Dual-Source Image-based Implementations.

PURPOSE: To determine the variance in virtual monochromatic computed tomography (CT) numbers from the same lesion, comparing the two clinically available dual-energy multidetector CT hardware implementations (single-source projection-based and dual-source image-based), in a phantom-based simulated abdominal environment. MATERIALS AND METHODS: This phantom-based study was exempt from institutional review board oversight. Polyethylene terephthalate spheres (15 and 18 mm) with two iodine-to-saline dilutions (0.8 and 1.2 mg of iodine per millilliter) were serially suspended in a cylindrical polypropylene bottle filled with diluted iodinated contrast material. The bottle was placed into a 36-cm-wide torso-shaped water phantom simulating the abdomen of a medium-sized patient. Dual-energy (80/140 kVp) and single-energy (100 and 120 kVp) scans were obtained with single-source and dual-source multidetector CT implementations. Virtual monochromatic images were reconstructed at energy levels of 40-140 keV (in 10-keV increments) in either the projection-space or image-space domain. A multivariate regression analysis approach was used to investigate the effect of energy level, lesion size, lesion iodine content, and implementation type on measured CT numbers. RESULTS: There were significant differences in the attenuation values measured in the simulated lesions with the single-source projection-based platform and the dual-source image-based implementation (P < .001 for all comparisons). The magnitude of these differences was greatest at lower monochromatic energy levels and at lower iodine concentrations (average difference at 40 keV: 25.7 HU; average difference at 140 keV: 7 HU). The monochromatic energy level and the lesion iodine concentration had a significant effect on the difference in the measured attenuation values between the two implementations, which indicates that the two imaging platforms respond differently to changes in investigated variables (P < .001 for all comparisons). CONCLUSION: There is a statistically significant variance in virtual monochromatic CT numbers from the same lesion examined with single-source projection-based and dual-source image-based implementations. The magnitude of the variance is a function of the selected energy level and the lesion iodine content.

Impact of dual-energy multi-detector row CT with virtual monochromatic imaging on renal cyst pseudoenhancement: in vitro and in vivo study.

PURPOSE: To investigate whether dual-energy multi-detector row computed tomography (CT) with virtual monochromatic imaging can overcome renal cyst pseudoenhancement in a phantom experiment and a clinical study. MATERIALS AND METHODS: This retrospective single-center HIPAA-compliant study was approved by the institutional review board, with waiver of informed consent. Four renal compartments inserted into torso phantoms were filled with saline to simulate the unenhanced state and with iodinated solutions to simulate the three levels of renal parenchyma enhancement (140, 180, and 240 HU). Saline-filled spheres simulating renal cysts (15 and 18 mm in diameter) were serially suspended in the renal compartments and imaged with dual-energy and single-energy multi-detector row CT at four different energy levels (80, 100, 120, and 140 kVp). In addition, 28 patients (mean age, 66 years ± 10; mean body mass index, 31.3 kg/m(2) ± 6.2) with 34 intrarenal cysts were included. Virtual monochromatic images were reconstructed in 10-keV increments at energy levels ranging from 40 to 140 keV. Phantom and clinical data were analyzed by using multivariate regression analysis. RESULTS: In the phantom experiment, all polychromatic image data sets showed pseudoenhancement (postcontrast attenuation increase >10 HU) in all investigated conditions, with a significant effect on cyst size (P <.001), location (P <.001), and renal background attenuation level (P <.001). Virtual monochromatic images at energy levels ranging from 80 to 140 keV did not show pseudoenhancement, with the minimum attenuation increase (mean, 6.1 HU ± 1.6; range, 1.6-7.7 HU) on 80-keV images. In patients, pseudoenhancement never occurred on virtual monochromatic images at energy levels ranging from 90 to 140 keV. Patient body size had a significant effect (P = .007) on selection of the optimal monochromatic energy level. CONCLUSION: Dual-energy multi-detector row CT with reconstruction of virtual monochromatic images at an optimal energy level can overcome renal cyst pseudoenhancement.

Gastrointestinal cancer surgery in patients with a prior ventriculoperitoneal shunt: the department of veterans affairs experience.

BACKGROUND: The estimated prevalence of hydrocephalus in all age groups is between 1% and 1.5%. Placement of a ventriculoperitoneal (VP) shunt in such patients offers them relatively normal lives. There are minimal data concerning the risk of postoperative complications in patients with shunts who undergo subsequent major visceral operations. We hypothesized that healthy adults who had VP shunts placed for acquired conditions and later underwent surgery for gastric or colon cancer would frequently have dense, shunt-related adhesions and high rates of adverse outcomes, particularly infection. METHODS: We assumed that all veterans were healthy on entry into military service. We searched national Department of Veterans Affairs databases from October 1994 through September 2003 to identify all Department of Veterans Affairs patients with shunts for acquired conditions and a curative-intent operation for stomach or colon cancer. We conducted chart reviews to determine their clinical courses. RESULTS: Five patients had codes for VP shunt, gastric cancer, and gastrectomy; 3 met our inclusion criteria. Fourteen had codes for VP shunt, colon cancer, and colectomy; 4 met our criteria. One of the evaluable gastrectomy patients had dense, shunt-related adhesions. None of the colectomy patients had notable adhesions. There were no postoperative complications in any of the seven patients. CONCLUSION: We believe this is the first report analyzing the clinical course of adults with VP shunts who later had major abdominal cancer surgery. The presence of a shunt was associated with dense adhesions in 1 (14%) of the 7 patients in this series, but not with an increased risk of postoperative complications.

SALL1 truncated protein expression in Townes-Brocks syndrome leads to ectopic expression of downstream genes.

Mutations in SALL1 lead to the dominant multiorgan congenital anomalies that define Townes-Brocks syndrome (TBS). The majority of these mutations result in premature termination codons that would be predicted to trigger nonsense-mediated decay (NMD) of mutant mRNA and cause haploinsufficiency. Our previous studies using a gene targeted mouse model (Sall1-DeltaZn) suggested that TBS phenotypes are due to expression of a truncated mutant protein, not haploinsufficiency. In this report, we strengthen this hypothesis by showing that expression of the mutant protein alone in transgenic mice is sufficient to cause limb phenotypes that are characteristic of TBS patients. We prove that the same pathogenetic mechanism elucidated in mice is occurring in humans by demonstrating that truncated SALL1 protein is expressed in cells derived from a TBS patient. TBS mutant protein is capable of dominant negative activity that results in ectopic activation of two downstream genes, Nppa and Shox2, in the developing heart and limb. We propose a model for the pathogenesis of TBS in which truncated Sall1 protein causes derepression of Sall-responsive target genes.

Appendectomy for appendicitis in patients with a prior ventriculoperitoneal shunt.

BACKGROUND: Approximately 18,000 cerebrospinal fluid shunts, the majority of which are ventriculoperitoneal, are placed each year in the United States. These patients may develop appendicitis and require surgery. Whether the risk of postoperative complications is increased in these patients is unknown. We sought to determine the clinical course of patients with ventriculoperitoneal (VP) shunts who undergo appendectomy for appendicitis. METHODS: A nationwide search of Department of Veterans Affairs databases was conducted to identify patients with a VP shunt who subsequently developed appendicitis and underwent appendectomy. Patient medical records were analyzed to determine if the presence of a VP shunt affected the surgical approach or the postoperative course of patients who underwent appendectomy. RESULTS: Ten patients had ICD-9-CM codes for both appendectomy and a VP shunt. Five met the inclusion criteria for the study and had sufficient data for analysis. Medical records indicated that all of the patients had perforated or gangrenous appendicitis with peritonitis. One patient's VP shunt was converted to a ventriculoatrial shunt. Another patient's shunt was removed when culture of his peritoneal fluid grew Gram-positive cocci. There were no instances of postoperative infection, shunt malfunction, or other complication. CONCLUSION: This is the only English language study, to our knowledge, of the clinical course of adults with VP shunts in place at the time of appendectomy for appendicitis. Such patients generally have no complications related to shunt malfunction or infection. In a minority of patients, shunt revision may be required.