Chang Hae Suh

Can Necrotizing Infectious Fasciitis Be Differentiated from Nonnecrotizing Infectious Fasciitis with MR Imaging

PURPOSE To retrospectively evaluate whether magnetic resonance (MR) imaging findings can be used to differentiate necrotizing infectious fasciitis (NIF) from nonnecrotizing infectious fasciitis (non-NIF). MATERIALS AND METHODS Institutional review board approval was obtained, but patient consent was not required for this retrospective review of records and images because patient anonymity was preserved. Thirty patients (seven with NIF, 23 with non-NIF) were included in the study. The following imaging findings were analyzed on fat-suppressed T2-weighted MR images: (a) signal intensity in the deep fascia (low, high, or mixed high and low), (b) thickness of abnormal signal intensity in the deep fascia (≥3 mm or <3 mm), (c) pattern of abnormal signal intensity in muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity), (d) degree of deep fascia involvement (partial or extensive), and (e) degree of compartment involvement (fewer than three compartments or three or more compartments). On contrast material-enhanced fat-suppressed T1-weighted images, the contrast enhancement patterns of the abnormal deep fascia (no enhancement, enhancement, or enhancement with nonenhancing portion) and the muscle (no abnormality, peripheral bandlike signal intensity, or patchy high signal intensity) were evaluated. The presence of abscesses in the subcutaneous fat layer was evaluated with all sequences. RESULTS The patients with NIF had a significantly greater frequency of (a) thick (≥3 mm) abnormal signal intensity on fat-suppressed T2-weighted images, (b) low signal intensity in the deep fascia on fat-suppressed T2-weighted images, (c) a focal or diffuse nonenhancing portion in the area of abnormal signal intensity in the deep fascia, (d) extensive involvement of the deep fascia, and (e) involvement of three or more compartments in one extremity (P < .05). CONCLUSION MR imaging is potentially helpful for differentiating NIF from non-NIF. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101164/-/DC1.

Differentiation of chronic focal pancreatitis from pancreatic carcinoma by in vivo proton magnetic resonance spectroscopy

Objective: To determine the differences between the in vivo proton magnetic resonance spectroscopy (1H-MRS) features of chronic focal pancreatitis and pancreatic carcinoma and to evaluate the possibility of discriminating chronic focal pancreatitis from pancreatic carcinoma by analysis of in vivo 1H-MR spectra. Methods: The 1H-MR spectra from 36 human pancreases were evaluated in vivo. This series included 15 cases of chronic focal pancreatitis and 21 cases of pancreatic carcinoma. All cases were confirmed histopathologically after surgical resection. The ratios of the peak area (P) of all peaks at 1.6-4.1 ppm to lipid (0.9-1.6 ppm) (P [1.6-4.1 ppm]/P [0.9-1.6 ppm]) in the chronic focal pancreatitis and pancreatic carcinoma groups were evaluated, and the results were compared. The sensitivity and specificity of the analysis were also evaluated by in vivo 1H-MR spectra for discriminating between chronic focal pancreatitis and pancreatic carcinoma. Results: In vivo 1H-MR spectra showed significantly less lipid in chronic focal pancreatitis than in pancreatic carcinoma. The ratio of P (1.6-4.1 ppm)/P (0.9-1.6 ppm) in chronic focal pancreatitis was significantly higher than that in pancreatic carcinoma (P < 0.05) because of a decreased peak area of lipids. The means ± SDs of P (1.6-4.1 ppm)/P (0.9-1.6 ppm) in the chronic focal pancreatitis and pancreatic carcinoma groups were 2.78 ± 1.67 and 0.51 ± 0.49, respectively. Using a value of <2.5 as positive for pancreatic cancer, the sensitivity and the specificity for pancreatic cancer were 100% and 53.3%, respectively. Conclusion: Chronic focal pancreatitis and pancreatic carcinoma can be distinguished from each other by analysis of in vivo 1H-MR spectra, and in vivo 1H-MRS can be a useful method for making a differential diagnosis between chronic focal pancreatitis and pancreatic carcinoma.

Gallbladder carcinoma and chronic cholecystitis:differentiation with two-phase spiral CT

The objective of the present study was to determine whether an analysis of two-phase spiral computed tomographic (CT) features provides a sound basis for the differential diagnosis between gallbladder carcinoma and chronic cholecystitis. Eighty-two patients, 35 with gallbladder carcinoma and 47 with chronic cholecystitis, underwent two-phase spiral CT. We reviewed the two-phase spiral CT features of thickness and enhancement pattern of the gallbladder wall seen during the arterial and venous phases. Mean wall thicknesses were 12.6 mm in the gallbladder carcinoma group and 6.9 mm in the chronic cholecystitis group. The common enhancement patterns seen in gallbladder carcinoma were (a) a highly enhanced thick inner wall layer during the arterial phase that showed isoattenuation with the adjacent hepatic parenchyma during the venous phase (16 of 35, 45.7%) and (b) a highly enhanced thick inner wall layer during both phases (eight of 35, 22.9%). The most common enhancement pattern of chronic cholecystitis was isoattenuation of the thin inner wall layer during both phases (42 of 47, 89.4%). In conclusion, awareness of the wall thickening and enhancement patterns in gallbladder carcinoma and chronic cholecystitis on two-phase spiral CT appears to be valuable in differentiating these two different disease entities.

MR Imaging in a Child with Scurvy: a Case Report

Scurvy is very rare disease in industrialized societies. Nevertheless, it still exists in higher risk groups including economically disadvantaged populations with poor nutrition, such as the elderly and chronic alcoholics. The incidence of scurvy in the pediatric population is very low. This study reports a case of scurvy in a 5-year-old girl with cerebral palsy and developmental delay based on MRI findings.

In-vivo Proton Magnetic Resonance Spectroscopy in Adnexal Lesions

Objective To explore the in-vivo 1H- MR spectral features of adnexal lesions and to characterize the spectral patterns of various pathologic entities. Materials and Methods Thirty-one patients with surgically and histopathologically confirmed adnexal lesions underwent short echo-time STEAM (stimulated echo acquisition method) 1H- MR spectroscopy, and the results obtained were analysed. Results The methylene present in fatty acid chains gave rise to a lipid peak of 1.3 ppm in the 1H- MR spectra of most malignant tumors and benign teratomas. This same peak was not observed, however, in the spectra of benign ovarian epithelial tumors: in a number of these, a peak of 5.2 ppm, due to the presence of the olefine group (-CH=CH-) was noted. The ratios of lipid peak at 1.3 ppm to water peak (lipid/water ratios) varied between disease groups, and in some benign teratomas was characteristically high. Conclusion An intense lipid peak at 1.3 ppm is observed in malignant ovarian tumors but not in benign epithelial tumors. 1H- MRS may therefore be helpful in the differential diagnosis of adnexal lesions.

Pilomatricoma in the head and neck : CT findings in three patients

We report three cases of pilomatricoma, one in the infrahyoid neck and the others in the preauricular area. In all cases, CT showed well marginated soft tissue masses that were located mainly in the subcutaneous fat, partly attaching to the overlying skin. There was no evidence of infiltration to deeper structures. Substantial amounts of calcification were found in one tumor. Pilomatricoma should be included in diagnostic consideration when CT shows a well marginated subcutaneous soft tissue mass adherent to the skin with or without visible calcification in the head and neck region.

Balloon dilation of intrahepatic biliary strictures for percutaneous extraction of residual intrahepatic stones

Intrahepatic ductal strictures in cholangiohepatitis present an obstacle to successful removal of retained ductal stones via T-tube tracts. We studied the effectiveness of stricture dilatation for stone removal.Fifteen patients with intrahepatic gallstones retained behind strictures underwent balloon dilatation of their strictures to allow stone extraction. All had prior surfical T-tube placement allowing percutaneous access. Balloon dilatation was successful in reducing or eliminating strictures in 86.7% (13 of 15 patients), and complete stone extraction after the successful dilatation was possible in 76.9% (10 of 13 patients). The reasons for failure were impacted stones and acute ductal angulation which prevented passage of catheters. It is concluded that balloon dilatation of intrahepatic biliary strictures is an effective adjunct for extraction of intrahepatic biliary calculi associated with recurrent pyogenic cholangiohepatitis.

Magnetic resonance imaging of bowel ischemia induced by ligation of superior mesenteric artery and vein in a cat model

Objective: To assess the usefulness of magnetic resonance (MR) imaging for detecting bowel ischemia with strangulation compared with histopathologic findings in an experimental cat model. Materials and Methods: Fourteen cats were assigned to the normal control group (n = 3), acute ischemic group (induced by ligation of superior mesenteric vessels for 3 hours, n = 7), and subacute ischemic group (induced by ligation of superior mesenteric vessels for 10 hours, n = 4). Using a 4.7-T MR scanner, contrast-enhanced T1-weighted images were obtained at 0, 10, 20, 30, and 60 minutes after bolus injection of contrast media. T1- and T2-weighted images were obtained from the extracted bowel wall and compared with histopathologic findings. Results: On contrast-enhanced MR images, the target-like bowel wall layers were clearly demonstrated and the submucosal layer showed the most prominent enhancement. At 10 minutes after administration of contrast media, the subacute ischemic group showed significantly lower enhancement of the submucosal layer than the normal or acute ischemic group (P <0.05). On T1-weighted images, there were not significant differences between the normal and ischemic bowel groups (P >0.05). On T2-weighted images, the signal intensity of all layers of acute ischemic bowel wall was significantly higher than that of the normal control or subacute ischemic group (P <0.05). Conclusion: Delayed contrast-enhanced MR images and T2-weighted images were helpful for detecting subacute and acute bowel ischemia with strangulation, respectively.

Computed Tomographic Features of Appendiceal Serositis in Pelvic Inflammatory Disease: Comparison With Pathological Findings

Objective: The purpose of this study was to describe the computed tomographic (CT) features of the appendiceal serositis in women with pelvic inflammatory disease and to compare these with the pathological findings. Methods: Appendiceal serositis was pathologically evaluated in patients with pelvic inflammatory disease who underwent surgery within 3 days of computed tomography. On retrospective review of CT findings, each appendix was evaluated for the following characteristics: location relative to the cecum, maximal diameter, morphology of wall thickening, contrast enhancement, and presence of appendicolith and cecal wall thickening. The presence of fatty infiltration of the periappendiceal fat, mesentery, and omentum was evaluated. The presence of pelvic abscess or ascites, lymph nodes, and paralytic ileus was noted. Results: On pathological review, 10 patients were shown to have appendiceal serositis: mild serositis in 3 patients, moderate in 4, and severe in 3. The maximal appendiceal diameter ranged from 5.4 to 8.9 mm (mean diameter, 7.1 ± 0.9 mm). Diffuse wall thickening with collapsed lumen was detected in 6 patients. Focal wall thickening with intraluminal gas bubbles or an air-fluid level was detected in 4 cases. Peripheral rim enhancement of the appendix was detected in 3 patients with focal wall-thickened appendix. There was no association between the feature of appendiceal wall thickening and the pathological severity of serositis. Mesenteric fatty infiltration was detected in 5 patients and omental fatty infiltration in 3 patients. Fatty infiltration of the mesentery and omentum was more commonly presented in patients with severe serositis. Pelvic abscesses, including pyosalpinx, were detected in 7 patients; a small amount of free fluid was seen in 8 patients. Conclusions: The CT findings of appendiceal serositis are diffuse or focal wall thickening without severe distension, common association with mesenteric fatty infiltration, and pelvic abscesses.

The usefulness of MR imaging of the temporal bone in the evaluation of patients with facial and audiovestibular dysfunction.

Objective To evaluate the clinical utility of MR imaging of the temporal bone in patients with facial and audiovestibular dysfunction with particular emphasis on the importance of contrast enhancement. Materials and Methods We retrospectively reviewed the MR images of 179 patients [72 men, 107 women; average age, 44 (range, 1-77) years] who presented with peripheral facial palsy (n=15), audiometrically proven sensorineural hearing loss (n=104), vertigo (n=109), or tinnitus (n=92). Positive MR imaging findings possibly responsible for the patients clinical manifestations were categorized according to the anatomic sites and presumed etiologies of the lesions. We also assessed the utility of contrast-enhanced MR imaging by analyzing its contribution to the demonstration of lesions which would otherwise not have been apparent. All MR images were interpreted by two neuroradiologists, who reached their conclusions by consensus. Results MR images demonstrated positive findings, thought to account for the presenting symptoms, in 78 (44%) of 179 patients, including 15 (100%) of 15 with peripheral facial palsy, 43 (41%) of 104 with sensorineural hearing loss, 40 (37%) of 109 with vertigo, and 39 (42%) of 92 with tinnitus. Thirty (38%) of those 78 patients had lesions that could be confidently recognized only at contrast-enhanced MR imaging. Conclusion Even though its use led to positive findings in less than half of these patients, MR imaging of the temporal bone is a useful diagnostic procedure in the evaluation of those with facial and audiovestibular dysfunction. Because it was only at contrast-enhanced MR imaging that a significant number of patients showed positive imaging findings which explained their clinical manifestations, the use of contrast material is highly recommended.