David M. Warshauer

Adult intussusception: Diagnosis and clinical relevance

Intussusception is relatively rare in the adult population and differs substantially from pediatric intussusception. Most adult intussusceptions identified at surgery are caused by a definable structural lesion, a substantial proportion of which are malignant, particularly in the colon. Small bowel intussusceptions, however, have a lower prevalence of malignancy. Diagnosis of adult intussusception can be made reliably with noninvasive imaging techniques. CT is now widely regarded as the modality of choice for diagnosing intussusception in adults, but ultrasound and MR imaging have also been used effectively. Determination of the presence of a malignant lead point remains problematic because an edematous or hemorrhagic intussuscipiens may mimic a mass on each modality. Markers for bowel viability have been described but are not precise. Treatment of the persistent symptomatic intussusception in which neoplasia is suspected is surgical, and preoperative reduction is contraindicated. Transient relatively asymptomatic enteric intussusceptions discovered by imaging may not require intervention.

Crohn’s Disease: Pilot study comparing MRI of the abdomen with clinical evaluation

Fourteen patients underwent magnetic resonance imaging (MRI) examination (16 studies) and clinical evaluation concurrently. MRI studies included gadolinium enhancement and TI-weighted fat-suppressed spin echo. Separate investigators determined the severity of disease on MR images and on clinical evaluation in a blinded fashion. MRI studies were evaluated for percentage of mural contrast enhancement, wall thickness, and length of diseased bowel. An MR product was generated using these parameters. Clinical evaluation used the Crohns Disease Activity Index (CDAI) and modified Index of the International Organization for the Study of Inflammatory Bowel Disease (IOIBD). Linear correlation was found between the MR product and clinical indexes of disease activity. The correlation between MR product and the modified IOIBD index was statistically significant (R(2) = 0.633, p = 0.0012). The correlation of MR product and CDAI was less close (R(2) = 0.274, p = 0.0373). Among individual MR parameters, length of diseased bowel showed the greatest correlation with CDAI (R(2) = 0.537, p = 0.012). Percentage contrast enhancement and bowel wall thickness showed significant correlation to the modified IOIBD index (R(2) = 0.739, p = 0.021) but not to the CDAI (R(2) = 0.004, p = 0.825). The results of this study show that the product of mural contrast enhancement, wall thickness, and length of diseased bowel correlated with clinical indexes of disease activity in Crohns disease. Our findings suggest that MRI may be useful in evaluating the severity of Crohns disease and may provide information complementary to clinical evaluation.

CT diagnosis of paraduodenal hernia

The computed tomographic (CT) findings of a right and left paraduodenal hernia are described. In the right paraduodenal hernia the major findings consist of encapsulation of small bowel loops in the right mid-abdomen with looping of arterial and venous jejunal branches behind the superior mesenteric artery. The findings of the left paraduodenal hernia are less specific and involve encapsulation of bowel loops at or above the level of the ligament of Treitz with intermittent dilatation.

CT diagnosis of celiac disease.

We present a case of celiac sprue in which the diagnosis was first suggested by the demonstration of intussusception on abdominal CT

Enhancement of the normal pancreas: comparison of manganese-DPDP and gadolinium chelate

The purpose of this paper was to compare manganese-DPDP (Mn-DPDP) and gadolinium chelate (Gd-DTPA) contrast agents for enhancement of the normal pancreas. A total of 14 patients with focal liver disease underwent Mn-DPDP and Gd-DTPA-enhanced 1.5T MR examinations using spoiled gradient-echo (FLASH) technique at tw separate times. Contrast agents were injected according to the currently recommended practices: GD-DTPA was injected as a rapid bolus injection in a dosage of 0.1 mmol/kg, and Mn-DPDP was injected as a slow IV injection in a dosage of 5 μmol/kg. Quantitative region of interest measurements were made in 11 patients, and percent contrast enhancement of the pancreas and pancreas-fat signal-to noise ratios (SNR) were determined for each agent. Images were also evaluated qualitatively by consensus reading of two investigators and overall scan quality was rated on a scale from 1 (poor) to 4 (very good). Enhancement of the pancreas immediately post Gd-DTPA was significantly higher than 15 min post Mn-DPDP (73.3 vs 36.3%;p = 0.003). On postcontrast images the pancreas-fat SNR measurements were 7.7 (i.e., pancreas higher in signal than fat) and 6.1 for Gd-DTPA and Mn-DPDP, respectively, which was significantly different (p < 0.001). Imagine quality was rated as 3.1 and 2.5 for Gd-DTPA- and Mn-DPDP-enhanced images respectively. The normal pancreas enhances significantly more with Gd-DTPA than with Mn-DPDP administered under the conditions of this study. Overall image quality is also greater on the Gd-DTPA-enhanced images.

DETERMINATION OF SERUM CREATININE LEVEL BEFORE INTRAVENOUS ADMINISTRATION OF IODINATED CONTRAST MEDIUM: A SURVEY

RATIONALE AND OBJECTIVESTo study the practice of obtaining serum creatinine before administering intravenous iodinated contrast medium and the costs associated with this practice. MATERIALS AND METHODSIn June 1993, a questionnaire was sent to 217 physicians who are members of the Society of Uroradiology or the Society of Computed Body Tomography/Magnetic Resonance. There were 149 respondents who completed a total of 70 questionnaires, providing a response rate of 69% (149/217). RESULTSThe percentage of institutions that always require a serum creatinine before administering intravenous contrast medium for excretory urography, body computed tomography, and head computed tomography was 13%, 20%, and 14%, respectively. In institutions where routine serum creatinine is not required, approximately 60% request a serum creatinine in either insulin-dependent or juvenile type 1 diabetes. The mean maximal acceptable time between the serum creatinine value and contrast administration is 29 days. It takes a mean of 69 minutes to get the results of a stat serum creatinine and costs a mean of 15 dollars for the test. In patients with no risk factors, the mean for the highest serum creatinine value at which respondents still gave contrast was 2.1 mg/dL; in patients with risk factors, the mean was 1.9 mg/dL. There was no correlation between the use of serum creatinine and the number of studies performed in the institution or the type of contrast used. CONCLUSIONSThe practice of requiring a pretest serum creatinine and its interpretation regarding the use of contrast media are quite variable. In view of this disparity in opinion, development and acceptance of a list of patients who are at increased risk for contrast-induced nephropathy may be desirable.

CT and MRI of hepatic focal nodular hyperplasia with peripheral steatosis

Focal nodular hyperplasia (FNH) is a benign liver condition, which generally does not contain fat. In this report we describe an unusual case in which multiple areas of FNH were surrounded by prominent peripheral fatty infiltration.

Intrahepatic extramedullary hematopoiesis: Mr, ct, and sonographic appearance

A 45-year-old patient with focal intrahepatic extramedullary hematopoiesis is presented in which the liver was imaged by CT, ultrasound, and MR. The appearance of the lesions on MR consisted of slightly increased signal on T2-weighted images with heterogeneous enhancement of some of the lesions during bolus infusion of gadolinium. The T1-weighted images postgadolinium showed no delayed enhancement.

ACR Appropriateness Criteria ® on Colorectal Cancer Screening

Colorectal cancer remains one of the most common causes of cancer death in this country. This malignancy is ideally suited for screening because the detection and removal of the precursor adenomatous polyp can prevent most colorectal cancers from ever forming. The choice of a test for screening involves consideration of various individual parameters, including patient age and the presence of risk factors for the development of colorectal cancer. Computed tomographic colonography (CTC) has emerged as the leading imaging technique for colorectal cancer screening in average-risk individuals on the basis of the evidence presented in this paper. The double-contrast barium enema is an alternative imaging test that is appropriate particularly when CTC is not available. In 2008, the American Cancer Society guideline for colorectal cancer screening was revised jointly with the US Multi-Society Task Force on Colorectal Cancer and the ACR to include CTC every 5 years as an option for average-risk individuals. Computed tomographic colonography is also the preferred test for colon evaluation after an incomplete colonoscopy. Imaging tests including CTC and the double-contrast barium enema are usually not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the new colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging.

Leiomyoma of the extraperitoneal round ligament: CT Demonstration

We report the computed tomography (CT) description of a leiomyoma involving the extraperitional portion of the round ligament. Although unusual, such a lesion may mimic other mass lesions in this vicinity including adenopathy, endometriomas, and inguinal hernias.