Biomedical subjects
Publications and source records attributed to N M Rofsky.
A patient with chronic renal insufficiency was found to have an indeterminate renal mass after renal ultrasound, non-contrast CT, and non-contrast MRI studies. The mass was correctly diagnosed as an enhancing tumor with gadolinium-DTPA-enhanced magnetic resonance imaging.
Despite the many imaging techniques available to evaluate the liver, deficiencies persist. The choice of the optimal method is still controversial, with competing issues of safety, efficacy, and cost. Numerous strategies to improve the results of liver imaging have been pursued, including the application of tissue-targeted contrast agents to magnetic resonance imaging (MRI). Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (Mn-DPDP) is one of several recently developed hepatobiliary agents, targeted to functioning hepatocytes. The Mn-DPDP-enhanced MRI has demonstrated promise in the clinical trials. Contrast-to-noise measurements have shown favorable results for Mn-DPDP-enhanced MR compared to non-enhanced T1- and T2-weighted images. The ability to characterize tumors of hepatocellular origin and an improved capability for lesion detection have also been demonstrated. Furthermore, the prolonged enhancement obtained with Mn-DPDP has extended the time during which effective contrast is maintained. Importantly, no clinically significant adverse events have been demonstrated. This report will detail the clinical experience with Mn-DPDP-enhanced MRI of the abdomen.
Five patients with renal insufficiency were studied with T1-weighted magnetic resonance (MR) imaging before and after intravenous administration of gadopentetate dimeglumine (0.1 mmol/kg) to characterize renal lesions that were detected with nonenhanced computed tomography (CT) and were considered indeterminate. Four patients demonstrated renal lesions that enhanced after gadolinium administration. A total of five lesions in these four patients were surgically resected and found to be renal cell carcinoma at pathologic examination. The fifth patient was spared surgery because a hyperattenuated lesion noted at nonenhanced CT did not enhance with intravenous gadolinium, indicating a benign cyst. Five incidentally occurring benign cysts removed at the time of nephrectomy in two of the patients did not demonstrate enhancement with gadolinium on MR images. Serial serum creatine levels were obtained before and after gadolinium administration in all patients; no changes were noted after gadolinium administration. Gadolinium-enhanced MR imaging is an effective method for characterizing renal lesions in patients with renal insufficiency. At the usual dosage, there appears to be no nephrotoxic reaction in these patients.
Five cases of myelolipoma of the adrenal are presented which contained only tiny foci of fat along with areas of punctate calcification. This computed tomographic (CT) appearance is less common for this neoplasm and has only been described in three of 26 previously published CT cases of this adrenal tumor. The presence of even tiny amounts of fat in an adrenal mass should alert the radiologist to the probable diagnosis of myelolipoma. Small foci of calcification are also frequently associated.
Specimens of breast milk were obtained from each breast in a lactating patient for a 24-hour period after a gadolinium-enhanced MR imaging examination was performed. A quantitative analysis of gadolinium content in specimens obtained at 2, 11, 17, and 24 hours after the intravenous administration of gadopentetate dimeglumine demonstrated that gadolinium is excreted in small amounts (total of 1.60 mumol during a 24-hour period) and in similar amounts from each breast. These results suggest that a waiting period of 24 hours, with active expression of breast milk from each breast, should provide a reasonable safety margin for allowing resumption of breast-feeding. Additional data will be required before establishing definitive recommendations.
Pregnant mice were exposed to one of five regimens at 9.5 days of gestation: no treatment (group 1), intraperitoneal injection of normal saline (group 2), intraperitoneal injection of gadopentetate dimeglumine (group 3), intraperitoneal injection of gadopentetate dimeglumine and magnetic resonance (MR) exposure (group 4), and MR exposure alone (group 5). At 18 days of gestation, the mice were sacrificed and fetuses were removed and examined for the following end points: litter size, number alive or dead, fetal weight, extremity morphology, eye and ear development, and appearance of the head. A total of 739 fetuses were analyzed: group 1 (n = 161), group 2 (n = 149), group 3 (n = 142), group 4 (n = 136), and group 5 (n = 151). The only statistically significant difference was a lower mean fetal weight in the saline-injection group compared with the control group. The results show that MR exposure with and without gadopentetate dimeglumine had no adverse effect on the end points analyzed.
In 22 patients with a diverse range of thoracic abnormalities, T2-weighted magnetic resonance (MR) images of the chest were obtained with electrocardiograph (ECG)-triggered turbo spin-echo (TSE), ECG-triggered conventional spin-echo (CSE), and nontriggered TSE sequences, and the images were compared. A 5-point rating scale was used by three radiologists experienced in MR imaging of the chest to independently evaluate the images for (a) freedom from ghosting, (b) clarity of heart wall and cardiac chambers, (c) clarity of mediastinal structures, (d) conspicuity of abnormalities, and (e) overall image quality. Evaluations were analyzed with statistical methods. For freedom from ghosting, clarity of heart wall and cardiac chambers, clarity of mediastinal structures, and overall image quality, the ECG-triggered TSE images were rated higher than the TSE images, which, in turn, were rated higher than the ECG-triggered CSE images at the P = .05 level of significance. No significant differences were seen between the pulse sequences in the conspicuity of abnormalities, although some differences were observed in individual cases. Our results suggest that ECG-triggered TSE imaging provides improved, time-efficient T2-weighted images of the chest.
A case of ureteral lymphoma with no other areas of involvement was incidentally discovered on MRI examination. Bilateral ureteral soft tissue infiltration, asymmetrical hydronephrosis, and abnormal enhancement of lymphomatous tissue were noted. A follow-up MRI after chemotherapy demonstrated significant decrease in the size of the periureteral disease and improvement in the extent of hydronephrosis.
BACKGROUND: We retrospectively reviewed the imaging features of a series of patients with cystic pancreatic masses, the majority of whom underwent imaging surveillance. METHODS: Imaging data from 30 patients with known cystic pancreatic masses were reviewed. Nine patients had surgical and/or cytologic classification. Of the 21 who were not operated on, all underwent serial imaging surveillance. Of these, five had corroborative endoscopic retrograde cholangiopancreatography and 16 were followed by only computed tomography and/or magnetic resonance imaging. RESULTS: In the nonoperated group, mean follow-up time was 30 months (3-144 months). Two patients demonstrated growth, and the remainder remain stable. In the patients who underwent surgery, invasive carcinoma was found in those with lesions larger than 4 cm, involvement of the main pancreatic duct, or visible solid components on the imaging study. Smaller lesions were benign. CONCLUSION: In patients with suspected cystic pancreatic neoplasms, surveillance might be possible if lesions are smaller than 2.5 cm, spare the main pancreatic duct, and demonstrate no solid components.
BACKGROUND: To compare three rapid T2-weighted pulse sequences with high-resolution turbo spin-echo (SE) magnetic resonance (MR) imaging for the diagnosis of leiomyoma and adenomyosis. METHODS: Eighteen patients referred for evaluation of suspected leiomyoma or adenomyosis underwent imaging at 1.5 T with a phased-array multicoil. Non-breath-hold, fat-saturated sagittal images of 4-7 mm, with equivalent voxel size, were obtained through the pelvis with the following three rapid pulse sequences: segmented, half-Fourier single shot turbo SE (HASTE), turboGRASE (TGSE) and turbo SE MR images. Mean acquisition times were 17 s (HASTE), 37 s (TGSE), and 42 s (turbo SE). These images were compared, in a blinded fashion, to high resolution turbo SE MR images, which are considered the "standard" for pelvic MRI. RESULTS: The three rapid pulse sequences, HASTE, TGSE and turbo SE, provided equivalent diagnostic information when compared with high-resolution turbo SE MR images. There was no significant difference in image quality, detection and localization of leiomyoma or in diagnosis of adenomyosis among the three rapid sequences. HASTE imaging demonstrated the least ghosting. CONCLUSION: Diagnostic T2-weighted images of benign uterine pathology may be obtained in as little as 17 s.
Twenty-nine patients with known or suspected focal hepatic disease were evaluated in a retrospective multi-institutional study comparing T1-weighted manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis (phosphate) (DPDP) enhanced magnetic resonance imaging (MRI) with dynamic sequential bolus contrast enhanced computed tomography (DBCT) for the detection of focal liver lesions. The patients were divided into four dose groups, receiving 3, 5, 8, or 10 mumol/kg of Mn-DPDP, delivered either via intravenous bolus (0.25 ml/sec) or infusion (1 ml/sec). Each of three readers, with varying levels of expertise in interpreting hepatic MRI and CT studies, identified more lesions on the Mn-DPDP enhanced MRI than the contrast enhanced CT images. Mn-DPDP enhanced MRI depicted the presence of extensive metastatic disease not seen with DBCT in three patients with fatty liver. The most experienced MRI reader saw more lesions per patient on the Mn-DPDP enhanced MRI than with DBCT, while the opposite held true for the most experienced CT reader. The best single exam for detection of hepatic lesions may be determined by the experience of the reader.
Bannayan-Zonana syndrome (BZS) is a genetic disorder with autosomal dominant inheritance characterized by macrocephaly and multiple hamartomas of mesodermal origin. Here we present a patient with BZS manifested by many of the classic features, as well as a high-flow upper extremity arteriovenous malformation (AVM). Although this rare syndrome was initially described in 1971, to our knowledge, this is the first report showing an association of AVM with BZS and the first report of this syndrome in the radiologic literature.
The purpose of this study was to compare three T1-weighted sequences for hepatic magnetic resonance (MRI) imaging with the use of a body phased array coil. Three different T1-weighted MR sequences were compared: a conventional spin echo (CSE); half-Fourier spin echo (HFSE), and a gradient recalled echo (GRE). Three independent reviewers compared the sequences both quantitatively and qualitatively. The T1-weighted GRE sequence scored highest for overall image quality (p < 0.001), lesion conspicuity (p = 0.012), and yielded the highest contrast to noise (C/N) values. GRE T1-weighted images are the best for hepatic MRI.
The objective of this article was to compare half-dose (0.05 mm/kg) gadolinium-enhanced dynamic hepatic MR imaging to standard doses (0.10 mm/kg). Eighteen patients for follow-up hepatic MR received 0.05 mm/kg of gadolinium DTPA dynamically with gradient-echo imaging. Imaging parameters were identical to a 0.10-mm/kg study; patients were imaged during multiple phases of contrast enhancement. Two readers assessed for enhancement patterns and characterization. Quantitative signal-to-noise ratios (S/N) were obtained for abdominal viscera and contrast-to-noise ratios (C/N) were obtained on up to three lesions. No significant difference for the arterial dominant phase (P > 0.05) was found. Significant differences were found in all categories during the portal venous phase (except pancreas) and equilibrium phase (except liver). Lesion C/N ratios were not significant at any point (P > 0.05). Sixty-two out of 64 lesions (97%) were identically characterized. Therefore, half-dose dynamic gadolinium-enhanced MR may have diagnostic value.
Dissection of the ascending aorta is usually associated with severe chest and/or back pain. We describe three young men, with pathologically proven cystic medial necrosis, who presented with atypical clinical symptoms and ascending aortic dissection diagnosed by MR imaging and surgery. Patients with cystic medial necrosis and aortic dissection may not present with a classic acute chest pain syndrome.
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 5 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.
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-enhanced 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.
A case of an unusually large cystic renal cell carcinoma demonstrated on plain film, CT, and magnetic resonance (MR) is presented. Though the origin of huge abdominal tumors can be difficult to determine, the CT and MR findings were able to correctly diagnose the mass as a malignant cystic kidney tumor.