Neil M. Rofsky

Appendicitis: the impact of computed tomography imaging on negative appendectomy and perforation rates

Objective:The purposes of this study were to investigate the use of computed tomography (CT) imaging in patients with suspected acute appendicitis and to evaluate the impact of CT on negative appendectomy and perforation rates. In patients clinically diagnosed of acute appendicitis the reported overall negative appendectomy rate is about 15–20%; 10% in men and 25–45% in women of childbearing age. This is associated with a perforation rate of 21–23%.Methods:This is a retrospective analysis of 146 consecutive patients presenting with clinical symptoms suspicious of appendicitis over a 2-yr period in whom CT examinations were performed before therapy was instituted. The overall negative appendectomy and perforation rates were calculated for the entire group, as well as for the 54 women aged 15–50 yr in the childbearing cohort.Results:The negative appendectomy rate was 4% in 122 patients operated on and the perforation rate was 22%. Among 36 women 15–50 yr of age operated on, the negative appendectomy rate was 8.3% and the perforation rate was 19%. Surgery was avoided in 24 patients, 18 of whom were women of childbearing age.Conclusions:The judicious use of CT imaging in patients with equivocal clinical presentation suspected of having appendicitis led to a significant improvement in the preoperative diagnosis. It resulted in a substantial decrease in the negative appendectomy rate compared to previously published reports, without incurring an increase in the perforation rate.

CT and MRI of diffuse liver disease

CT and MRI contribute important information to the clinical evaluation of diffuse liver disease. In some cases, these modalities can establish a diagnosis that was not ascertained histologically, which is often the case when sampling errors prevent a definitive tissue diagnosis. Characteristic alterations of liver attenuation on CT, signal changes on MRI, and morphological changes appreciated with both modalities can be used to diagnose fatty infiltration, some parenchymal deposition diseases, and cirrhosis. Furthermore, hepatocellular disease can be confirmed in the setting of indeterminate clinical and laboratory findings. Significant overlap in the imaging findings of this wide range of disorders continues to limit specificity; however, at a minimum, these techniques provide a rapid means to a noninvasive evaluation that often guides clinical decisions. Faster scanning techniques available with CT and MRI may provide additional information by assessing contrast dynamics. This review of CT and MRI in diffuse liver disease considers the diagnostic utility and clinical implications of these modalities. Pathological findings relevant to imaging considerations are discussed.

Successful multimodal therapy for kaposiform hemangioendothelioma complicated by Kasabach-Merritt phenomenon: case report and review of the literature.

We present the management challenge provided by a patient with kaposiform hemangioendothelioma associated with Kasabach-Merritt phenomenon. A female child presented at 14 months of age with an ecchymotic swelling of her right upper arm and axilla. Subsequently, she developed profound thrombocytopenia and hypofibrinogenemia (Kasabach-Merritt phenomenon). Biopsy of the lesion revealed kaposiform hemangioendothelioma, which has been reported as the predominant pathologic diagnosis associated with Kasabach-Merritt phenomenon. To achieve involution of the lesion and preserve function of the arm, the following interventions were involved: embolization, systemic interferon, cyclophosphamide, epsilon aminocaproic acid, and compression therapy. The clinical management of this patient was formidable until we arrived at the proper combination of therapies. Multimodal intervention may be required to manage fastidious hemangioendotheliomas of childhood, achieve clinical improvement, and prevent further morbidity.

Comparison between in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging

PURPOSE Our goal was to compare in-phase (IP) and opposed-phase (OP) sequences for GRE breath-hold hepatic imaging. METHOD Non-contrast-enhanced IP and OP GRE breath-hold images were obtained in 104 consecutive patients referred for abdominal MRI at 1.0 T. For both sequences, the TR, FA, matrix, FOV, slice thickness, interslice gap, and measurements were kept constant. Images were compared quantitatively [liver/spleen and liver/lesion signal difference/noise ratio, (SD/N)] and qualitatively (artifacts, lesion detection and conspicuity, and intrahepatic anatomy). RESULTS There was no statistically significant difference when comparing IP and OP sequences for liver/spleen and liver/lesion SD/N or for the qualitative parameters. In patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SD/N (0.9 and -1.2, respectively) than the IP sequences (20 and 17, respectively). Furthermore, in several cases with fatty infiltration, many more lesions were identified using IP images. CONCLUSION The use of IP and OP GRE sequences provides complementary diagnostic information. Focal liver lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.

Gadolinium-enhanced 3D MRA of the aortic arch vessels in the detection of atherosclerotic cerebrovascular occlusive disease

PURPOSE Our goal was to evaluate non-breath-hold Gd-enhanced 3D MR angiography (MRA) for the detection of atherosclerotic occlusive disease of the aortic arch vessels and to compare image quality with two breath-hold techniques. METHOD One hundred sixty consecutive patients with known or clinically suspected atherosclerotic cerebrovascular occlusive disease underwent Gd-enhanced 3D MRA of the aortic arch and great vessels. One hundred twenty-six examinations were performed with the body coil after infusion of 40 ml of Gd-DTPA; 89 of these were performed without breath-holding and 37 were acquired during suspended respiration. Thirty-four examinations were performed in a body phased-array coil with breath-holding, a timing examination, and 20 ml of contrast agent by manual (n = 17) or power (n = 17) injection. Images were evaluated for the presence of blurring and ghosting artifacts and venous enhancement. Of the 27 patients who underwent non-breath-hold MRI and digital subtraction angiography (DSA), two readers blinded to the DSA results retrospectively evaluated the MRA examinations for the presence of occlusive disease of the innominate, carotid, subclavian, and vertebral arteries. DSA correlation was not evaluated for the 71 breath-hold studies. RESULTS Sensitivity and specificity for arch vessel occlusive disease with non-breath-hold MRA were 38 and 94% for Reader A and 38 and 95% for Reader B. Breath-holding significantly reduced blurring and ghosting artifacts (p < 0.001) when compared with non-breath-hold imaging, and use of 20 ml of contrast medium, with a timing examination, resulted in significantly less venous enhancement than seen with 40 ml (p < 0.001). CONCLUSION Non-breath-hold Gd-enhanced 3D MRA is insensitive for detecting arch vessel occlusive disease. Breath-hold imaging, in conjunction with a timing examination and a lower dose of contrast agent, improves image quality, but further studies are needed to assess diagnostic accuracy.

Interrupted aortic arch: diagnosis with gadolinium-enhanced 3D MRA.

PURPOSE Our goal was to describe the use of gadolinium-enhanced 3D MR angiography (MRA) in the diagnosis of interrupted aortic arch (IAA). METHOD A review of our MR data base from a 1 year period yielded three patients (1 day, 8 days, and 16 years old) with IAA. All were referred for evaluation of aortic arch abnormalities, only one of whom had suspected IAA. Patients were imaged at 1.5 T with a 3D spoiled gradient echo pulse sequence (TR/TE 3.8-8/1.3-2.7 ms) following the administration of intravenous gadolinium chelates. Surgical correlation was available in all cases. RESULTS In the patient with clinically suspected IAA, a previously unsuspected aberrant right subclavian artery was identified that was not seen on preoperative echocardiography. In another patient with a history of previous mediastinal surgery, IAA was diagnosed without concomitant cardiac anomalies, suggesting surgical ligation. In the remaining patient, IAA was detected as well as a patent truncus arteriosus. CONCLUSION Gadolinium-enhanced 3D MRA may provide for a rapid diagnosis of IAA that may not be possible with other noninvasive modalities. The rapid acquisition time enables unstable pediatric patients to spend minimal time in the MR suite.

Siderotic nodules at MR imaging: regenerative or dysplastic?

Objective To determine if iron containing “siderotic” nodules detected at magnetic resonance (MR) imaging are regenerative (RN) or dysplastic (DN) and to attempt to identify features that may distinguish them. Material and Methods MR imaging (1.5 T) was performed on 77 cirrhotic patients who underwent orthotopic liver transplantation within 0–117 days (mean 30 days) of MR imaging. Two readers retrospectively evaluated breath-hold gradient-echo pulse sequences (echo time ≥9.0 ms, flip angle ≤45°) for the presence of hypointense nodules, which were classified as micronodular (≤3 mm), macronodular (>3 mm), or mixed. Nodule distribution was classified as focal (<5), scattered (5–20), or diffuse (>20) per slice. Thin section pathologic correlation was available in all cases, and Prussian blue iron stains were performed. Results Of 35 patients with pathologically proven siderotic nodules, 10 (29%) had at least 2 siderotic DN. MR detected siderotic nodules in 10 of 10 (100%) patients with siderotic DN and RN, and in 18 of 25 patients (72%) with siderotic RN only. Conclusion Siderotic RN cannot be reliably distinguished from siderotic DN with MR imaging, and therefore the widely used term “siderotic regenerative nodule” should be avoided and replaced by “siderotic nodule.”

Magnetic resonance cholangiopancreatography accurately predicts the presence or absence of choledocholithiasis

Accurate common bile duct (CBD) imaging in patients with biliary calculi is an important determinant of specific therapy. Noninvasive methods to evaluate calculi in the CBD have limited accuracy and rely mainly on ultrasonography and computed tomography. Magnetic resonance cholangiopancreatography (MRCP) is a new noninvasive modality available to evaluate the biliary system. This study was undertaken to assess the accuracy of MRCP in predicting the presence or absence of CBD stones in patients at increased risk for choledocholithiasis. The medical records of 48 patients with a final diagnosis of biliary calculous disease undergoing MRCP between November 1995 and April 1997 were retrospectively reviewed. Three groups were identified: choledocholithiasis (n = 19), gallstone pancreatitis (n = 11), and uncomplicated cholelithiasis (n = 18). In all patients the presence or absence of CBD calculi, as determined by MRCP, was correlated with the final diagnosis obtained from endoscopic retrograde cholangiopancreatography (ERCP) (n = 19), intraoperative cholangiography (n = 6), CBD exploration (n = 13), or clinical follow-up (n = 10). Sensitivity, specificity, and accuracy of MRCP were determined. The major clinical indications for MRCP in the 48 patients ware abnormal liver function tests followed by hyperamylasemia. Twenty patients were diagnosed with CBD stones and 28 were not. MRCP correctly predicted the presence of CBD stones in 19 of 20 patients and failed to detect CBD stones in one patient with gallstone pancreatitis. MRCP incorrectly predicted the presence of CBD stones in 3 of 28 patients ultimately found to have gallstones and no CBD stones. MRCP correctly predicted the absence of CBD stones in the other 25 patients including 10 patients with gallstone pancreatitis. Overall, MRCP had a sensitivity of 95%, a specificity of 89%, and an accuracy of 92%. MRCP is an accurate, noninvasive test for evaluating the CBD duct for the presence or absence of calculi in patients suspected of having CBD stones. Our data support the use of MRCP in the preoperative evaluation of these patients as findings may influence therapeutic decisions.

A multisite phase iii study of the safety and efficacy of a new manganese chloride-based gastrointestinal contrast agent for mri of the abdomen and pelvis

The purpose of this study was to evaluate the safety and efficacy of a manganese chloride‐based oral magnetic resonance (MR) contrast agent during a Phase III multisite clinical trial. Two hundred seventeen patients were enrolled who were already scheduled for MRI of the abdomen and/or pelvis. In this group of patients, it was postulated that the use of an oral agent would better allow discrimination of pathology from bowel. Patients with known gastrointestinal pathology including peptic ulcer disease, inflammatory bowel disease, obstruction, or perforation were excluded to minimize confounding variables that could affect the safety assessment. Of these 217 patients, 18 received up to 900 mL of placebo, and 199 patients were given up to 900 mL of a manganese chloride‐based oral contrast agent, LumenHance® (Bracco Diagnostics, Inc.). Safety was determined by comparing pre‐ and post‐dose physical examinations, vital signs, and laboratory examinations and by documenting adverse events. Efficacy was assessed by unblinded site investigators and two blinded reviewers who compared pre‐ and post‐dose T1‐ and T2‐weighted MRI scans of the abdomen and/or pelvis. In 111 (57%) of the 195 cases evaluated for efficacy by site investigators (unblinded readers), MRI after LumenHance provided additional diagnostic information. Increased information was found by two blinded readers in 52% and 51% of patients, respectively. In 44/195 cases (23%) unblinded readers felt the additional information would have changed patient diagnosis and in 50 patients (26%), it would have changed management and/or therapy. Potential changes in patient diagnosis or management/therapy were seen by the two blinded readers in 8–20% of patients. No clinically significant post‐dose laboratory changes were seen. Forty‐eight patients (24%) receiving LumenHance and four patients (22%) receiving placebo experienced one or more adverse events. Gastrointestinal tract side effects were most common, seen in 29 (15%) of LumenHance patients and in 3 (17%) of the placebo patients. LumenHance is a safe and efficacious oral gastrointestinal contrast agent for MRI of the abdomen and pelvis.J. Magn. Reson. Imaging 1999;10:15–24.

Magnetic resonance imaging with magnetic resonance cholangiopancreatography accurately predicts resectability of pancreatic carcinoma

Accurate preoperative staging of pancreatic malignancy aids in directing appropriate therapy and avoids unnecessary invasive procedures. We evaluated the accuracy of magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) in determining resectability of pancreatic malignancy. Twenty-one patients with suspected pancreatic malignancy underwent dynamic, contrast-en-hanced breath-hold MRI with MRCP prior to surgical evaluation. Results of this study were correlated with operative results and pathologic findings. The sensitivity, specificity, and accuracy of MRI with MRCP in detecting a mass, determining the nature of the mass, and predicting lymph node involvement and resectability were determined. MRI with MRCP correctly identified the presence of a pancreatic mass in all 21 of these patients. Following pathologic correlation, it was determined that MRI with MRCP was 81 % accurate in determining the benign or malignant nature of the pancreatic mass and 43% accurate in predicting lymph node involvement. In predicting resectability, MRI with MRCP had a sensitivity of 100%, specificity of 83%, positive predictive value of 94%, negative predictive value of 100%, and accuracy of 95%. MRI with MRCP is an accurate, noninvasive technique in the preoperative evaluation of pancreatic malignancy. Information obtained from MRI with MRCP including identification of a mass and predicting tumor resectability may be of value in staging and avoiding unnecessary invasive diagnostic procedures in patients with pancreatic cancer.