Eric K. Outwater

Abdominal Iron Distribution in Sickle Cell Disease: Mr Findings in Transfusion and Nontransfusion Dependent Patients

Objective Our goal was to determine the difference in iron distribution between transfusion dependent (TD) and nontransfusion dependent (NT) patients with sickle cell disease (SCD). Materials and Methods The T2-weighted and T2*-weighted abdominal MR images in nine cases of homozygous SCD were reviewed to determine the distribution of low signal from iron in five TD and four NT patients. Results All eight patients with visualized spleens had decreased splenic signal intensity. One patient who had no history of splenectomy had no visualized splenic tissue. The majority of both groups had renal cortex of low signal intensity that was attributable to iron deposition from intravascular hemolysis and was not correlated with clinical renal abnormalities. None of the NT group had liver or pancreas of low signal intensity, while all five TD patients had decreased liver signal intensity and three of five had decreased pancreatic signal intensity. Conclusion Decreased pancreatic signal intensity can occur in TD patients, perhaps suggesting total body iron overload. Nontransfusion dependent sickle cell patients usually have normal hepatic signal intensity and do not have total body iron overload, even in the presence of renal and splenic iron deposition.

Intraabdominal desmoplastic small cell tumor: CT and MR findings.

The pertinent radiologic findings in two cases of a recently described tumor, intraabdominal desmoplastic small cell tumor, are presented. This is an aggressive, usually lethal malignant neoplasm of the peritoneum occurring in boys and young men with a marked predilection for intraperitoneal spread. In both cases, CT or MR demonstrated a necrotic intraperitoneal mass with peritoneal metastases. Given the limited differential diagnosis, intraabdominal desmoplastic small cell tumor should be strongly considered as a diagnosis of an intraperitoneal neoplasm in young males.

Location, size, and distribution of mediastinal lymph node enlargement in chronic congestive heart failure.

Purpose The purpose of this study is to identify the prevalence, location, and size of enlarged mediastinal lymph nodes in patients with chronic congestive heart failure and to correlate the presence of lymph node enlargement with cardiac ejection fraction. Methods Sixty-six consecutive, retrospectively identified patients underwent computer tomography (CT) imaging of the thorax as part of a routine work-up prior to cardiac transplantation from 1993 to 1996. CT images of 44 of these patients were independently examined by 3 radiologists for evidence of pulmonary edema, pleural effusions, and the presence, size, and location of lymph nodes >1 cm in short axis. Multigated acquisition (MUGA) scans were available for cardiac ejection fraction assessment in 38 of the 44 patients. Results Twenty-nine (66%) patients had at least 1 mediastinal lymph node >1 cm. The mean ejection fraction was significantly less for patients with lymph node enlargement when compared with patients without lymph node enlargement (20% versus 35%; P < 0.01). Adenopathy was observed in 81% of patients with a calculated ejection fraction of <35%. No patient with an ejection fraction of >35% had lymph node enlargement. There was no correlation between pulmonary edema and the frequency of lymph node appearance. Sixty-three percent of the enlarged nodes were pretracheal, with a mean short axis diameter for all the enlarged nodes of 1.3 cm. Conclusions Enlarged mediastinal lymph nodes were observed in 81% of patients with a calculated ejection fraction of <35%, most commonly in the pretracheal group. The presence of the lymph nodes did not correlate with CT evidence of pulmonary edema.

Benign gynecologic disease: applications of magnetic resonance imaging.

Magnetic resonance imaging (MRI) can contribute to cost-effective management in women with suspected myomas or adenomyosis and can provide precise presurgical mapping prior to myomectomy or correction of mullerian duct anomalies. MRI is also valuable in patients with suspected adnexal masses that are not detected sonographically or where definitive diagnosis of juxtauterine myoma, cystic teratoma, or hemorrhagic mass may alter management.

MR imaging of pancreatic disorders.

Newer magnetic resonance imaging techniques offer greater precision in diagnosing various pancreatic disorders, primarily through faster image acquisitions. These include breath-hold rapid T1-weighted images, fast spin-echo sequences, and angiographic techniques. Altered signal intensity on fat-saturated T1-weighted images is one of the principal signs of pancreatic disease, and may affect the gland diffusely with chronic pancreatitis or focally with carcinoma. T2-weighted sequences primarily characterize peripancreatic fluid, ductal obstruction, carcinoma, or cystic or mucinous tumors. Heavily T2-weighted cholangiographic reconstructions are important to evaluate ductal obstructions. Dynamic gadolinium-enhanced images improve the accuracy for identifying and characterizing islet-cell tumors and pancreatic adenocarcinomas.

MR imaging of mucinous adenocarcinoma of the prostate

Magnetic resonance imaging is considered the primary imaging modality for staging adenocarcinoma of the prostate (1). The recent introduction of the endorectal surface coil has allowed for higher resolution images of the prostate and improved accuracy of staging (2,3)

MR Imaging Techniques for Evaluation of the Pancreas

New techniques have transformed magnetic resonance (MR) imaging of the pancreas from an imaging examination that had been inferior to computed tomography (CT) in diagnostic capability, to one that today may well be superior for many applications. These technologic advances include chemical-shift imaging, fast spin-echo T2-weighted imaging and its modifications, such as MR cholan-giopancreatography, and dynamic gadolinium-enhanced imaging. Taken together, these techniques can detect diseases that may be difficult to appreciate on CT, such as small pancreatic adenocarcinomas, islet cell tumors, and ductal abnormalities and calculi. Newer intravenous contrast agents such as Mangafodipir, as well as oral contrast agents, have not been widely used but show promise for future improved pancreatic MR imaging.

Perirectal cystic paragonimiasis: endorectal coil MRI.

We report the transrectal ultrasonographic (TRUS) and endorectal surface coil MR findings for paragonimiasis involving the perirectal space. The patient presented with voiding difficulty. TRUS showed a well demarcated, oval-shaped hyperechoic mass in the perirectal space. On endorectal MR images, the lesion was depicted as a well defined cystic mass with homogeneous intermediate signal intensity on T1-weighted images and heterogeneous hyperintensity on T2-weighted images. Ectopic paragonimiasis can appear as a well defined cystic mass in the peritoneum and should be included in the differential diagnosis of cystic mass in the abdomen and pelvic cavity, including the perirectal space.

Lipid in Renal Clear Cell Carcinoma: Detection on Opposed-Phase Gradient-Echo MR Images

PURPOSE To determine if comparison of in-phase and opposed-phase gradient-echo magnetic resonance (MR) images enables detection of lipid in renal clear cell carcinoma. MATERIALS AND METHODS A retrospective search of MR and pathologic records identified 43 patients with biopsy-proved renal masses who underwent in-phase and opposed-phase MR imaging. Thirty-three patients had renal cell carcinoma (27 with clear cell carcinoma), and 10 patients had other renal tumors. With MR images, a region-of-interest measurement of signal intensity of the renal mass was divided by that of reference tissue. In each patient, a ratio of these region-of-interest measurements on the opposed-phase images to those on the in-phase images was calculated and termed the opposed-phase/in-phase signal intensity ratio (OIR). RESULTS The mean OIR of clear cell carcinomas was significantly different from that of other renal masses (P < .0002); in 16 (59%) of 27 patients with clear cell carcinoma, the OIR was less than 2 standard deviations below the mean OIR of other masses. In cases of clear cell carcinoma, focal signal intensity on opposed-phase images was less than that on in-phase images. CONCLUSION On opposed-phase images, some clear cell carcinomas show relative focal and diffuse loss of signal intensity. In renal masses, this signal intensity loss-which is consistent with lipid-does not necessarily indicate angiomyolipoma.