Gadolinium-enhanced Magnetic Resonance Imaging Studies Research Articles

Laparoscopic Hepatectomy with Selective Hepatic Artery Clamping for A Hyperintense Hepatic Adenoma on Hepatospecific Gadolinium-Enhanced Magnetic Resonance Imaging: The Great Pretender

Introduction: Focal nodular hyperplasia and hepatocellular adenoma are benign hepatic tumors and differential diagnosis is important as hepatic adenomas may complicate with hemorrhage and malignant transformation. Magnetic resonance imaging with gadolinium-enhanced contrast agents is the best noninvasive diagnostic tool for benign hepatic tumors. Nevertheless, atypical radiological findings can make differential diagnosis a challenge. Presentation of case: We report a young female patient with large hepatic benign tumor with intralesional hemorrhage that disclosed hyper-intensity on hepatobiliary phase on a gadolinium-enhanced magnetic resonance imaging study, suggestive of focal nodular hyperplasia. As this type of tumor usually do not complicate with bleeding, surgical resection was proposed and a laparoscopic right posterior hepatic sectionectomy with selective hepatic artery clamping was performed. Pathology disclosed an inflammatory hepatic adenoma. Discussion: Hepatic adenomas may present as hyper-intense tumors on hepatobiliary phase of gadoliniumenhanced magnetic resonance imaging. Surgical resection still has a role on the treatment of benign hepatic tumors. Laparoscopic liver resections must be considered, even when a major hepatectomy is planned, as this approach has proved safe and effective. Selective hepatic artery clamping during minimally invasive liver surgery may be an option to reduce intraoperative bleeding, remnant liver ischemia and postoperative hepatic failure. Conclusion: We reported a young female patient with a benign hepatic tumor complicated with hemorrhage suggestive of a focal nodular hyperplasia on gadolinium-enhanced magnetic resonance imaging study. A laparoscopic hepatectomy was performed and final pathology disclosed an inflammatory hepatocellular adenoma.

Usefulness of dynamic contrast-enhanced MRI in the evaluation of the viability of acute scaphoid fracture

To evaluate the usefulness of dynamic gadolinium-enhanced magnetic resonance imaging (MRI) for assessing the viability of the proximal pole of the scaphoid in patients with acute scaphoid fractures. Eighteen consecutive patients with acute scaphoid fracture who underwent dynamic gadolinium-enhanced MRI 7days or less before surgery were prospectively included between August 2011 and December 2012. All patients underwent MR imaging with unenhanced images, enhanced images, and dynamic enhanced images. A radiologist first classified the MRI results as necrotic or viable based on T1- and T2-weighted images only, followed by a second blinded interpretation, this time including analysis of pre- and post-gadolinium administration images and a third blinded interpretation based on the time-intensity curve of the dynamic enhanced study. The standard of reference was the histologic assessment of a cylindrical specimen of the proximal pole obtained during surgery in all patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for unenhanced, enhanced, and dynamic gadolinium-enhanced MRI studies. The sensitivity, specificity, PPV, and NPV were 67, 67, 50, and 80% for unenhanced images, 83, 100, 100, and 92 for enhanced images, and 83, 92, 83, and 92 for dynamic contrast-enhanced images. Our data are consistent with previously reported data supporting contrast-enhanced MRI for assessment of viability, and showing that dynamic imaging with time-intensity curve analysis does not provide additional predictive value over standard delayed enhanced imaging for acute scaphoid fracture.

Arterial Anatomy of the Talus: A Cadaver and Gadolinium-Enhanced MRI Study

Avascular necrosis following a fracture of the talar neck may be secondary to the injury itself, or may result from the surgical approach and exposure during treatment. We sought to define the arterial anatomy of the talus using gadolinium-enhanced magnetic resonance imaging (MRI) and through gross dissection following latex injection of cadaver limbs. The use of gadolinium-enhanced MRI for the evaluation of the arterial supply of the talus has not been previously reported. We utilized 12 fresh frozen cadaver limbs to study the arterial anatomy of the talus. The anterior tibial, posterior tibial, and peroneal arteries were isolated and cannulated with polyethylene catheters. Gadolinium was injected into the cannulas, and conventional MRI sequences including suppressed and unsuppressed 3D gradient echo sequences obtained. Following MRI, latex was injected into the cannulas and gross dissection performed. In addition, the vascular constraints to anteromedial and anterolateral approaches to the talus were defined. MRI proved useful in the present study to confirm the presence of specific arterial branches in situ, as well as to demonstrate the rich anastomotic network in and around the talus. A branch to the medial talar neck that has not been previously identified is described which was found in nine of the specimens. This newly described branch to the medial talar neck was consistently noted to be lacerated following a standard anteromedial approach to the talus. The use of gadolinium-enhanced MRI provided very detailed images demonstrating a rich and complex anastomotic arterial network that surrounds and perforates the talus. A thorough understanding of the anatomy and meticulous dissection are essential to prevent unnecessary further injury to the vasculature when treating fractures of the talus.

Comparison of Portal Venous and Delayed Phases of Gadolinium-Enhanced Magnetic Resonance Imaging Study of Cirrhotic Liver for the Detection of Contrast Washout of Hypervascular Hepatocellular Carcinoma

To retrospectively compare portal venous phase (PVP) and delayed phase (DP) for the detection of tumor washout at gadobenate dimeglumine-enhanced liver magnetic resonance imaging (MRI) in cirrhotic patients with hypervascular hepatocellular carcinoma (HCC). Thirty-three patients with 55 HCCs underwent 1.5-T MRI by means of fat-suppressed T1-weighted sequence obtained before and after gadobenate dimeglumine administration, during early and late arterial phases, PVP (70 seconds), and DP (180 seconds). Detection rates of contrast washout of hypervascular HCCs and tumor-to-liver contrast on PVP and DP were measured and compared. Among 54 hypervascular HCCs, washout was present in 24 (44%) of 54 tumors on PVP and in 44 (82%) of 54 on DP (P < 0.001). In 20 (37%) of 54 tumors, washout was deemed present only on DP. Delayed phase images yielded significantly higher mean tumor-to-liver contrast absolute values compared with PVP images (-24.5 [56.1] vs -9.3 [52.6], P = 0.001). Delayed phase is superior to PVP for the washout detection of hypervascular HCC at gadobenate dimeglumine-enhanced MRI of cirrhotic liver.

Interstitial temperature mapping during Prolieve transurethral microwave treatment: Imaging reveals thermotherapy temperatures resulting in tissue necrosis and patent prostatic urethra

Objectives Temperature mapping of the prostate during transurethral microwave thermotherapy and imaging of the resultant zones of tissue necrosis have been previously performed using several commercial systems. This study was performed using the Prolieve Thermodilatation System, which simultaneously compresses the prostate with a 46F balloon circulating heated fluid and delivering microwave energy into the prostate. Methods Interstitial temperature mapping during Prolieve treatment was performed on 10 patients with benign prostatic hyperplasia using 24 temperature sensors arrayed throughout the prostate. Voiding cystourethrograms were performed on 3 additional patients treated without temperature mapping to document the patency of the prostatic urethra 1 hour after treatment. Gadolinium-enhanced magnetic resonance imaging studies were performed on all patients 1 week after treatment to determine the extent and pattern of tissue necrosis resulting from transurethral microwave thermotherapy. Results Interstitial temperature mapping found that the heating pattern generated by the Prolieve system created average peak temperatures of 51.8°C an average of 7 mm away from the prostatic urethra. These temperatures were greater near the bladder neck and mid-gland than toward the prostatic apex. Subtherapeutic temperatures were seen adjacent to the urethra, consistent with the viable tissue seen on gadolinium-enhanced magnetic resonance imaging sequences. Magnetic resonance imaging also revealed necrotic zones that were consistent with sustained temperatures greater than 45°C. Voiding cystourethrograms showed widely patent prostatic urethras 1 hour after treatment. Conclusions Transurethral microwave thermotherapy with the Prolieve Thermodilatation System produced sustained therapeutic temperatures that resulted in tissue necrosis while maintaining viable tissue surrounding a temporarily dilated prostatic urethra.

Isolated inflammatory coxitis associated with protrusio acetabuli: a new form of juvenile idiopathic arthritis?

Isolated hip disease in the context of chronic childhood inflammatory arthritis is uncommon. This paper reports 14 children who presented to the rheumatology and orthopaedic departments of our hospitals with severe hip symptoms, and who continued to have primarily hip disease throughout their clinical course. Our aim was to characterize and present the relevant demographic, clinical, investigational, treatment and outcome data from the above cohort. All paediatric cases with the diagnosis of protrusio acetabuli, Otto pelvis or idiopathic chondrolysis who were seen in the past 15 yr at Great Ormond Hospital and Middlesex Hospital in London were identified and their case notes were searched retrospectively for relevant information. In 11 cases, the disease progressed to involve no joints other than the contralateral hip. None were considered to have a specific subtype of juvenile idiopathic arthritis (JIA) and all tested were negative for HLA-B27. Elevation of serum inflammatory markers was variable. Protrusio acetabuli was the predominant radiological feature. There were definite inflammatory changes on the gadolinium-enhanced magnetic resonance imaging study in all patients who had this procedure performed (seven cases). Microbiological investigations were all consistently negative. Severe hip disease resulted in considerable ongoing symptoms and disability. Six cases were treated with disease-modifying anti-rheumatic drugs. Total hip replacement has been required in four patients to date, with major functional improvement. These cases represent severe and disabling primary hip disease with considerable clinical and investigational inflammatory features. Such a mode of presentation has not been described previously in the context of childhood chronic inflammatory arthritides, and may represent a separate oligoarthritis subtype of JIA.

Neuroma as a cause of oculomotor palsy in infancy and early childhood

Introduction: Third nerve palsy in infancy and early childhood is rare. We present 5 children with isolated monocular oculomotor palsy originally believed to be idiopathic but subsequently documented to be secondary to a presumed neuroma of the third nerve, distal to the mesencephalon. Methods: Retrospective case review of patient charts from 1995 through 1999 was performed. Results: Mean age at initial presentation was 14.4 months (range, 2-36 months). Two patients were male. Initial manifestation was an incomplete paresis in all 5 cases; 2 patients presented initially with exotropia, 2 with ptosis, and 3 with anisocoria. The pupil was ultimately involved in all cases. Progression to total paresis occurred in 4 of 5 patients over a mean of 13 months (range, 4-22 months). Findings of initial neuroimaging were believed to be normal in all cases but further thin-section gadolinium-enhanced magnetic resonance imaging studies, including coronal views, revealed enlargement and/or enhancement of the subarachnoid or intracavernous portion of the oculomotor nerve. Aberrant regeneration did not develop in any case throughout follow-up (mean, 49.4 months). Visual acuity was decreased on the ipsilateral side in all cases, consistent with amblyopia. No patient had neurofibromatosis. Conclusions: Suspicion for neuroma should be high in infants and young children with acquired, isolated, apparently idiopathic third nerve palsy. Serial gadolinium-enhanced, 1- to 2-mm thin-section magnetic resonance imaging with coronal views is essential for proper diagnosis. (J AAPOS 2001;5:9-12)

Inhibition of peridural fibrosis after laminectomy using low-dose external beam radiation in a dog model.

Clinical studies have demonstrated a significant association between the presence of extensive postlumbar discectomy peridural scar formation and the recurrence of low back and radicular pain. Low-dose perioperative radiation therapy has previously been demonstrated to inhibit peridural fibrosis after laminectomy in a rat model. The current study was designed to measure the effect of low-dose radiation on postlaminectomy peridural fibrosis development in a larger animal model. Three dogs underwent a total of 12 lumbar hemilaminectomies. For each animal, two levels received 1) external beam radiation 24 hours before surgery, 2) surgery alone, or 3) radiation alone. Radiation was administered in a single fraction of 700 cGy using computed tomographic guidance for dosimetry planning. The isodose distribution was such that the dose conformed to the posterior epidural space with minimal exit dose to normal tissue. Port films were used to confirm the correct levels. Gadolinium-enhanced magnetic resonance imaging (MRI) of the lumbar spines was obtained before the animals were killed 12 weeks after surgery. The spines were harvested, and axial sections through the laminectomy defect were stained with hematoxylin and eosin and Masson's trichrome. All specimens were evaluated for extent of fibrosis along the dura, density of fibrosis, nerve root entrapment, and sublaminar fibrosis. There were no complications from the surgery, and no new neurological deficits were noted. There was a statistically significant difference between the irradiated and nonirradiated groups regarding the extent of fibrosis (P = 0.001) and the density of fibroblasts (P = 0.001). There was also a marked difference in nerve root entrapment (P = 0.182) and the presence of sublaminar fibrosis (P = 0.061) between the treatment and control groups. MRI revealed less gadolinium enhancement at the irradiated levels compared with the nonirradiated levels, confirming the usefulness of MRI in predicting the degree of epidural fibrosis. Low-dose external beam radiation therapy administered 24 hours before laminectomy in a dog model significantly decreased the extent and density of peridural fibrosis as well as nerve root entrapment and sublaminar fibrosis. This treatment strategy may be efficacious in patients with recurrent radicular pain after lumbar discectomy that is thought to be secondary to peridural fibrosis on the basis of gadolinium-enhanced MRI studies, and who might benefit from reoperation for nerve root decompression.

Gadolinium-enhanced magnetic resonance imaging in experimental facial nerve paralysis.

Recently, it has been reported that the facial nerve shows enhancement on gadolinium-enhanced magnetic resonance imaging (Gd-MRI) in patients with such conditions as Bell’s palsy or traumatic facial nerve paralysis. The site of involvement in Bell’s palsy remains unknown, and accurate lesion-site information is useful for surgical planning in cases of facial nerve paralysis. The importance of this technique in detecting the lesion site has been discussed, but the mechanism of facial nerve enhancement is unknown. In the present study, in order to elucidate the correlation between facial nerve enhancement and lesion site, Gd-MRI study was performed in the rabbit.

Spinal lesions: quantitative and qualitative temporal evolution of gadopentetate dimeglumine enhancement in MR imaging.

Seventy gadolinium-enhanced magnetic resonance imaging studies were reviewed, and 36 were selected for quantitative and qualitative analysis of the temporal evolution of contrast medium enhancement of spinal lesions. In the extradural space, lesions often showed mild increase of enhancement on delayed images, but enhancement was always visible on immediate postcontrast images. In the intradural extramedullary space, tumor nodules demonstrated most prominent enhancement on early images, although subtle, strandlike enhancement of the nerve roots showed some delayed uptake of contrast medium on later images. In the intramedullary space, enhancement often increased on delayed images, although this increase was usually mild. For clinical purposes, immediate postcontrast imaging should be sufficient to depict the majority of spinal lesions, regardless of location. However, selected cases, such as necrotic spinal cord tumors, will require delayed imaging.