Nodule Enhancement Research Articles

Prognostic role of magnetic resonance imaging vs. computed tomography for hepatocellular carcinoma undergoing chemoembolization.

Computed tomography (CT) and magnetic resonance imaging (MRI) play important roles in diagnosis and staging of hepatocellular carcinoma (HCC). However, prognostic roles of radiological characteristics are not yet determined. Eighty-eight patients treated with chemoembolization were analysed. Radiological parameters at baseline were assessed in all patients using both dynamic CT and MRI. Treatment responses were assessed using modified RECIST 4 weeks after the first chemoembolization. Gross vascular invasion (GVI), bile duct invasion, irregular tumour margin (ITM), peripheral ragged enhancement (PRE) and satellite nodules on CT or MRI were associated with non-response (stable disease or progression) after chemoembolization respectively (all P ≤ 0.05). GVI, ITM and PRE on CT or MRI were also independently associated with poor overall survival (OS) respectively (all P ≤ 0.05). Using these results, a prognostic scoring system for CT and MRI were developed; 0, absence of all three features (GVI, ITM and PRE); 1, presence of one feature; 2, presence of two features; and 3, presence of three features. After adjusting tumour size, tumour number and alpha-foetoprotein level, both CT and MRI scores were independently associated with OS (both P < 0.001). Patients with CT or MRI score ≥2 had a worse OS than those with score <2 (adjusted hazard ratios, 3.837 and 2.938 respectively). MRI-specific parameters such as signal intensity on T2- or T1-weighted images, fat signal or hyperintensity on diffusion-weighted images did not have prognostic value (all P > 0.05). Radiological parameters by CT and MRI may be useful in biological characterization of tumours and prognostification for HCC treated with chemoembolization.

Computed Tomography Assessment of Ablation Zone Enhancement in Patients With Early-Stage Lung Cancer After Stereotactic Ablative Radiotherapy.

Stereotactic ablative radiotherapy (SABR) offers a curative treatment for lung cancer in patients who are marginal surgical candidates. However, unlike traditional surgery the lung cancer remains in place after treatment. Thus, imaging follow-up for evaluation of recurrence is of paramount importance. In this retrospective designed Institutional Review Board-approved study, follow-up contrast-enhanced computed tomography (CT) exams were performed on sixty one patients to evaluate enhancement pattern in the ablation zone at 1, 3, 6, and 12 months after SABR. Eleven patients had recurrence within the ablation zone after SABR. The postcontrast enhancement in the recurrence group showed a washin and washout phenomenon, whereas the radiation-induced lung injury group showed continuous enhancement suggesting an inflammatory process. The textural feature of the ablation zone of enhancement and perfusion as demonstrated in computed tomography nodule enhancement may allow early differentiation of recurrence from radiation-induced lung injury in patients' status after SABR or primary lung cancer.

Coexistence of Spinal Intramedullary Tuberculoma and Multiple Intracranial Tuberculomas.

Spinal intramedullary tuberculoma remains a very rare entity of central nervous system tuberculosis. This is the same with the coexistence of spinal intramedullary and intracranial tuberculomas that remains extremely rare with less than 20 cases reported at present. Authors describe this uncommon case by analyzing a 65-year-old female patient who had past history of kidney transplantation due to stage 5 chronic kidney disease and pulmonary tuberculosis on medication. The patient experiences progressive paraplegia and numbness on both lower extremities. Magnetic resonance imaging demonstrated an intramedullary mass at T9-10 level and multiple intracranial enhancing nodules. Microsurgical resection of spinal intramedullary mass was performed and the lesion was histopathologically confirmed as Mycobacterium tuberculosis. Efficient diagnosis and management of this rare disease are reviewed along with previously reported cases.

"One-shot" endovascular management of cerebral aneurysm and fourth ventricle hemangioblastoma in a pregnant woman

Aneurysmal subarachnoid hemorrhage (aSAH) during pregnancy is a serious condition [1]. The bestmanagement of aSAHduring pregnancy is not yet established, although endovascular coiling has gained favor over the last few years [2]. The incidence of hemangioblastoma of the posterior fossa in pregnancy is extremely low [3]. Apregnantwomanpresented to the “Maggiore della Carita”Hospital in December 2009 having experienced sudden onset seizures and deterioration of consciousness at 27 weeks of pregnancy. The patient’s systemic blood pressurewas 100/50mmHg and eclampsiawas therefore excluded. CT and MRI scans showed subarachnoid hemorrhage, blood in the lateral ventricles, and ventricular dilation (Fig. 1). The fourth ventricle was occupied by a small mass—with hyperintense nodule enhancement on T2weighted imaging after gadolinium injection—rounded by a small cyst with ring enhancement. MR angiography revealed a subarachnoid aneurysm arising from the right internal carotid artery. The patient underwent digital subtraction angiography that confirmed the presence of a subarachnoid aneurysm of the right internal carotid artery and a hypervascularized nodule with arteriovenous shunt in the posterior fossa, fed by the posterior and anterior inferior cerebellar artery—consistent with hemangioblastoma. Following consultation with neurosurgeons, anesthesiologists, obstetricians, and neuroradiologists, the decision to immediately treat both lesions by an endovascular approachwas taken. Before themedical procedure, the patient was advised about the potential risks and benefits of the intervention and she provided informed consent. To begin, the posterior inferior cerebellar artery to the hemangioblastoma was navigatted with a flow-directed microcatheter to reach the hypervascularized nodule. Then, 0.7 mL of a mixture of glue diluted to 20% in Lipiodol (Guerbet, Bloomington, IN, USA) was injected into the nidus, followed by complete angiographic devascularization of the lesion (Figs. 2, 3). Immediately after, the aneurysm was coiled with three platinum bare coils. The procedure was uneventful. CT scan performed 24 hours after the procedure showed ventricular shrinking to a normal size (Fig. 4). The patient had good clinical status, with a Glasgow Coma Scale score of 14. At 38 weeks of pregnancy the patient was admitted for a scheduled cesarean delivery, resulting in the successful birth of a healthy neonate weighing 3220 g and with an International Journal of Gynecology and Obstetrics 129 (2015) 79–88

English

Introduction: The term intracranial space occupying lesions includes lesions which expand in volume to displace normal neural structures. They give rise to the various symptoms like focal seizures, paralysis, features of raised intracranial tension and false localizing signs. AIMS & OBJECTIVES: To determine the role of computed tomography in evaluation of space occupying lesions of brain, assessment of the site, nature and extent, age and sex prevalence of space occupying lesions. MATERIAL & METHODS: The present study was conducted on one hundred patients with space occupying lesions of the brain presenting with various neurologic symptoms or incidental findings. Patients of all age groups suspected to have intracranial space occupying lesions were included in the study. Results were expressed as mean ± SD and proportions as percentages. Results: Most of the cases of hyperdense lesions were intracerebral hemorrhages, meningioma, lymphoma and medulloblastoma. High grade astrocytomas were heterogenous hypodense lesions with irregular ring enhancement associated perilesional edema and mass effect. Low grade astrocytomas had minimal rim/ mural nodule enhancement. Intracranial tuberculoma and neurocysticercosis showed ring with nodular enhancing. Calcification was seen in tuberous sclerosis, neurocysticercosis, meningiomas, oligodendrogliomas, arteriovenous malformations and dermoid cyst. Congenital lesions had variable presentation ranging from cystic to mixed pattern lesions. CONCLUSIONS: In developing countries, CT imaging remains as a major diagnostic modality, with easy accessibility and technical ease as compared to MRI.

Assessing probability of malignancy in solid solitary pulmonary nodules with a new Bayesian calculator: improving diagnostic accuracy by means of expanded and updated features

A crucial point in the work-up of a solitary pulmonary nodule (SPN) is to accurately characterise the lesion on the basis of imaging and clinical data available. We introduce a new Bayesian calculator as a tool to assess and grade SPN risk of malignancy. A set of 343 consecutive biopsy or interval proven SPNs was used to develop a calculator to predict SPN probability of malignancy. The model was validated on the study population in a "round-robin" fashion and compared with results obtained from current models described in literature. In our case series, receiver operating characteristic (ROC) analysis showed an area under the curve (AUC) of 0.893 for the proposed model and 0.795 for its best competitor, which was the Gurney calculator. Using observational thresholds of 5% and 10% our model returned fewer false-negative results, while showing constant superiority in avoiding false-positive results for each surgical threshold tested. The main downside of the proposed calculator was a slightly higher proportion of indeterminate SPNs. We believe the proposed model to be an important update of current Bayesian analysis of SPNs, and to allow for better discrimination between malignancies and benign entities on the basis of clinical and imaging data. • Bayesian analysis can help characterise solitary pulmonary nodules • Volume doubling time (VDT) is a good predictor of malignancy • A VDT of between 25 and 400 days is highly suggestive of malignancy • Nodule size, enhancement, morphology and VDT are the best predictors of malignancy.

Benign mural nodules within fluid collections at MRI after soft-tissue sarcoma resection.

The purpose of this study was to determine the prevalence and clinical significance of nodules within fluid collections on MRI after surgical resection of soft-tissue sarcoma. This retrospective study included 175 patients who underwent resection of primary soft-tissue sarcoma and whose postoperative MRI reports mentioned fluid. Images were reviewed to determine the presence of fluid collections of 1 cm or greater in diameter in the surgical bed and any nodule (measuring ≥ 0.7 cm) within the collection. Signal intensity and characteristics of each collection and rim and presence of septa or blood products were recorded. Size, signal intensity, and contrast enhancement of nodules were reviewed. Nodules were classified as benign or malignant on the basis of histologic results or clinical or MRI follow-up. Fluid collections were present in 75 patients. Of those, 45 collections (60%) showed homogeneous fluid signal intensity and 30 (40%) were heterogeneous; septa were present in 45 (60%) and blood products in 12 (16%). Most collections showed a thin rim (59%) and rim enhancement (88%). Nodules were present along the inner wall of six (8%) collections. Four (66%) nodules enhanced and two (33%) were T1 hyperintense. At follow-up MRI, two nodules were stable in size, one decreased, and three resolved. Nodules in three patients were biopsied; all were benign. Two other patients had no recurrence at follow-up, and another died at 3 months. A nodule within a postoperative fluid collection at MRI after soft-tissue sarcoma resection generally does not represent tumor recurrence; short-interval follow-up MRI is recommended rather than immediate biopsy.

Computed tomography and magnetic resonance imaging findings of inflammatory myofibroblastic tumors of the head and neck

Inflammatory myofibroblastic tumor (IMT) is a rare tumor of mesenchymal origin that commonly occurs in the lung. Because of its non-specific clinical and imaging features, IMT is often misdiagnosed as a malignant tumor. There have been few imaging reports on IMT of the head and neck. To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of inflammatory myofibroblastic tumors (IMTs) of the head and neck. Six patients with IMTs of the head and neck confirmed by histopathologic examination were analyzed retrospectively. The mean patient age was 40 years. The tumor locations in the six patients were as follows: left bridge of the nose (one), right infratemporal fossa (two), and left parotid gland (three). Three patients who underwent CT all had soft tissue masses or nodules and no calcification. Bridge of the nose tumor showed a homogeneous isodense nodule and mild homogeneous enhancement. Infratemporal fossa tumor showed a homogeneous low density mass and intermediate homogeneous enhancement. Left parotid gland tumor showed a heterogeneous, mostly low density mass, and intermediate heterogeneous enhancement. T1-weighted images of the parotid gland tumors were hypointense; the infratemporal fossa tumor was isointense. T2-weighted images were mildly hypointense and of mixed hypo- and isointensity in the two parotid gland tumors; the infratemporal fossa tumor was homogeneously mildly hypointense. Heterogeneous intermediate enhancement was demonstrated in one parotid gland and the infratemporal fossa patients and mild homogeneous enhancement in another parotid gland patient. The imaging features of IMTs of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MRI may suggest the diagnosis of IMT. IMT should be included in the differential diagnosis of regional tumors.

Differentiation of Branch Duct Intraductal Papillary Mucinous Neoplasms From Serous Cystadenomas of the Pancreas Using Contrast‐Enhanced Sonography

The purpose of this study was to determine whether contrast-enhanced sonography can improve the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas of the pancreas compared to conventional (unenhanced) sonography alone. Between March 2008 and May 2012, there were 20 patients with branch duct intraductal mucinous neoplasms and 25 with serous cystadenomas in our institute, for whom preoperative conventional and contrast-enhanced sonographic results were available. The final diagnosis was obtained by histopathology. Various conventional and contrast-enhanced sonographic characteristics were retrospectively evaluated by 2 radiologists in consensus. A receiver operating characteristic curve analysis was used to evaluate the diagnostic value of conventional and contrast-enhanced sonography for discriminating between the two entities. Three conventional sonographic characteristics (microcysts, cysts with internal echoes, and main pancreatic duct dilatation) and 2 contrast-enhanced sonographic characteristics (communication between the lesion and main pancreatic duct and enhancement of mural nodules) significantly improved the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas. The area under the receiver operating characteristic curve increased from 0.691 with conventional sonography to 0.859 with combined contrast-enhanced and conventional ultrasonography (P = .043). In this series of patients, the addition of contrast-enhanced sonography to conventional sonography improved the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas.

Budd-Chiari Syndrome Caused by TIPS Malposition: A Case Report.

Budd-Chiari syndrome refers to hepatic pathology secondary to diminished venous outflow, most commonly associated with venothrombotic disease. Clinically, patients with Budd-Chiari present with hepatomegaly, ascites, abdominal distension, and pain. On imaging, Budd-Chiari syndrome is hallmarked by occluded IVC and or hepatic veins, caudate lobe enlargement, heterogeneous liver enhancement, intrahepatic collaterals, and hypervascular nodules. Etiopathological factors for Budd-Chiari syndrome include several systemic thrombotic and nonthrombotic conditions that can cause venous outflow obstruction at hepatic veins and/or IVC. While the transjugular intrahepatic portosystemic shunt (TIPS) is used as a treatment option for Budd-Chiari syndrome, Budd-Chiari syndrome is not a well-known complication of TIPS procedure. We report a case of Budd-Chiari syndrome that occurred in a transplanted cirrhotic liver from malpositioned proximal portion of the TIPS in IVC causing occlusion of the ostia of hepatic veins which was subsequently diagnosed on contrast-enhanced CT.

Intramedullary Spinal Lesions Involving the Conus Medullaris: MR Imaging Features for Differential Diagnosis

Purpose : Intramedullary spinal lesions in the conus medullaris (CM), including tumors and vascular lesion, are rarely reported. We reported various MR features of intramedullary spinal cord lesions involving the CM including ependymoma, hemangioblastomas, dermoid cyst, ventriculus terminalis and spinal AVF and tried to discuss them for differential diagnosis. Materials and Methods: Six patients (male: female = 4:2, mean age = 44.3 year old) were enrolled from the clinical database of our institute from 2004 to 2010 and their radiological images and clinical symptoms were reviewed retrospectively. All patients had taken initial and postoperative MRI with contrast enhancement using gadopentate dimeglumine (GdDTPA). These images were analyzed by tumor size, location, signal intensity relative to the spinal cord, vascular flow voids, syrinx or cyst, edema and enhancement pattern. Results: Contrast enhancement was seen in all intramedullary masses. An eccentric enhancing nodule was noted in two hemangioblastomas and unusual peripheral rim enhancement with septation was seen in ventriculus terminalis. Patchy enhancement of the CM was observed in spinal arteriovenous fistula (AVF). Extensive cord edema adjacent to the intramedullary lesions was seen in four cases and syrinx was noted in three cases. Vascular signal voids were found in two hemangioblastomas and one spinal AVF. Conclusion: In evaluation of intramedullary spinal lesions in the CM, it is necessary to consider these unusual MR findings and discriminate various pathologies with prudence and caution. Index words : Conus medullaris∙Intramedullary lesion∙Spinal arteriovenous fistula∙Ventriculus terminalis Hemangioblastoma∙Dermoid cyst∙Ependymoma

The analysis of enhancement pattern of hepatic inflammatory pseudotumor on contrast-enhanced ultrasound

The aim of this study was to assess the role of contrast-enhanced ultrasound (CEUS) in the characterization of hepatic inflammatory pseudotumor (IPT). We retrospectively reviewed 36 cases of histopathologically diagnosed IPT. Nodule enhancement appearances during the arterial, portal, and delayed phases were defined as hyperenhancement, isoenhancement, hypoenhancement, and non-enhancement compared with the surrounding liver parenchyma. Statistical analysis was performed by the one-way ANOVA and χ (2) tests. Among total 36 cases, 7 nodules were absent of contrast enhancement during all three phrases on CEUS. Twenty-nine nodules appeared different forms of enhancement in arterial phase. Diffuse homogeneous hyperenhancement, diffuse heterogeneous hyperenhancement, peripheral rim-like enhancement, and diffuse iso-enhancement were found in 10, 12, 5, and 2 of the nodules, respectively. Twenty-five nodules showed hypoenhancement in portal and delayed phases. Four nodules showed contrast washed out synchronously with normal liver parenchyma. The median time to enhancement, median time to peak, and median time to wash out of the nodules were 17s (range 11-28s), 23s (range 14-42s), and 45s (range 23-100s), respectively. No statistical significant differences were found in the above parameters of nodule enhancement and proportion of enhancement patterns when dividing the nodules into subgroups by nodule size. IPT displays a variety of enhancement patterns due to pathological changes in the course of disease progression. Some characteristics on CEUS may be helpful in the differential diagnosis of IPT.

The peptide-encoding CEP1 gene modulates lateral root and nodule numbers in Medicago truncatula

The role of MtCEP1, a member of the CEP (C-terminally encoded peptide) signaling peptide family, was examined in Medicago truncatula root development. MtCEP1 was expressed in root tips, vascular tissue, and young lateral organs, and was up-regulated by low nitrogen levels and, independently, by elevated CO2. Overexpressing MtCEP1 or applying MtCEP1 peptide to roots elicited developmental phenotypes: inhibition of lateral root formation, enhancement of nodulation, and the induction of periodic circumferential root swellings, which arose from cortical, epidermal, and pericycle cell divisions and featured an additional cortical cell layer. MtCEP peptide addition to other legume species induced similar phenotypes. The enhancement of nodulation by MtCEP1 is partially tolerant to high nitrate, which normally strongly suppresses nodulation. These nodules develop faster, are larger, and fix more nitrogen in the absence and presence of inhibiting nitrate levels. At 25mM nitrate, nodules formed on pre-existing swelling sites induced by MtCEP1 overexpression. RNA interference-mediated silencing of several MtCEP genes revealed a negative correlation between transcript levels of MtCEP1 and MtCEP2 with the number of lateral roots. MtCEP1 peptide-dependent phenotypes were abolished or attenuated by altering or deleting key residues in its 15 amino acid domain. RNA-Seq analysis revealed that 89 and 116 genes were significantly up- and down-regulated, respectively, by MtCEP1 overexpression, including transcription factors WRKY, bZIP, ERF, and MYB, homologues of LOB29, SUPERROOT2, and BABY BOOM. Taken together, the data suggest that the MtCEP1 peptide modulates lateral root and nodule development in M. truncatula.

Diagnostic Performances of Various Gray-Scale, Color Doppler, and Contrast-Enhanced Ultrasonography Findings in Predicting Malignant Thyroid Nodules

Ultrasonography is the most frequently used clinical tool for the identification, assessment, and follow-up of thyroid nodules. The purpose of this research was to evaluate the value of diagnostic ultrasonography indicators, to obtain rankings of the most valuable indicators in the differential diagnosis of thyroid nodules, and to analyze the optimal diagnostic points and clinical values. One hundred forty-four patients with 172 thyroid nodules underwent preoperative ultrasonography examinations, including gray-scale ultrasonography (GSUS), color Doppler ultrasonography (CDUS), and contrast-enhanced ultrasonography (CEUS). Fourteen indicators of thyroid nodules on GSUS, CDUS, and CEUS were selected to evaluate all thyroid nodules. The differences between the benign and malignant thyroid nodules in all indicators were analyzed by the chi-squared test; the diagnostic ultrasonography values were obtained by logistic regression; and the optimal diagnostic points were explored by receiver operating characteristic curve analysis. Of the 172 thyroid nodules that were surgically removed, 78 were benign and 94 were malignant. Ten indicators of GSUS and CEUS showed significant differences between the benign and malignant nodules (p<0.05), whereas four CDUS indicators had no value. The rankings of the valuable indicators were obtained according to their odds ratios (ORs). The top four indicators were ring enhancement and homogeneity of enhancement on CEUS, and microcalcification and halo on GSUS. These indicators were the most valuable, with ORs of greater than 20 in the differential diagnosis of benign and malignant thyroid nodules. The other six indicators-the relative arrival time of the nodule on CEUS, interior echogenicity on GSUS, peak interior echogenicity on CEUS, shape on GSUS, peak peripheral echogenicity on CEUS, and orientation on GSUS-were also valuable, with ORs less than 20. The areas under the receiver operating characteristic curves for GSUS, CEUS, and the combination of GSUS and CEUS in the diagnosis of thyroid nodules were 0.936, 0.910, and 0.966, respectively. Five positive features of the 10 valuable indicators on GSUS and CEUS defined the cut-off for the diagnosis of malignant thyroid nodules, with a sensitivity of 89.4% (84/94), specificity of 93.6% (73/78), and accuracy of 91.3% (157/172). The ring enhancement and homogeneity of enhancement of thyroid nodules on CEUS and the microcalcification and halo on GSUS were the four most valuable indicators in the differential diagnosis of thyroid nodules. Conjoint analysis of specific features of thyroid nodules on GSUS and CEUS could enhance the diagnostic value of thyroid nodules.

Evidence of diagnostic enhancement pattern in hepatocellular carcinoma nodules ≤2 cm according to the AASLD/EASL revised criteria

To define the percentage of small (≤2 cm) hepatocellular carcinoma (HCC) nodules showing the diagnostic enhancement pattern at CEUS, computed tomography (CT), and gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging. 42 cirrhotic patients (26 male, 16 female; 67 ± 12 years) with 46 biopsy-proven HCCs ≤2 cm were included. Each HCC was scanned by CEUS, contrast-enhanced CT, and Gd-BOPTA-enhanced MR imaging. Nodule enhancement was evaluated by two readers. Independent analysis was followed by consensual analysis and the proportion of HCCs with the diagnostic enhancement pattern (nodule hyperenhancing on hepatic arterial phase and hypoenhancing on portal venous-late phase) on CEUS, CT, and MR imaging was compared by chi-square test. Very good inter-reader agreement was observed on hepatic arterial phase and portal venous-late phase: CEUS, k = 0.89 and 0.85; CT, k = 0.91 and 0.88; MR imaging, k = 0.96 and 0.94. CEUS and CT did not differ in the percentage of HCC nodules with a diagnostic enhancement pattern (18/46 and 16/46; P = 0.66), while MR imaging revealed the diagnostic pattern in higher percentage of nodules (29/46; P = 0.012) in comparison to CEUS and CT. CEUS and contrast-enhanced CT did not differ in the percentage of small HCC nodules with diagnostic enhancement pattern, while Gd-BOPTA-enhanced MR imaging revealed the diagnostic pattern in a higher nodule number in comparison to CEUS and CT.

Incidental Focal Uptake in Oropharynx Due to Lingual Thyroid on Diagnostic 131I Whole-Body Scan After Total Thyroidectomy

After total thyroidectomy for papillary thyroid carcinoma, a 37-year-old woman underwent a 2-mCi (131)I whole-body scan which demonstrated focal uptake in the anterior neck and in the oropharynx. Preoperative contrast-enhanced neck computed tomography demonstrated a small enhancing nodule typical for ectopic thyroid at the tongue base. She was then treated with 150 mCi (131)I. Small asymptomatic lingual thyroid remnants typically do not affect high-dose (131)I therapy.

Sclerosing Angiomatoid Nodular Transformation of the Spleen: CT and MRI Features With Pathologic Correlation

The objective of this study was to describe the CT and MRI features of sclerosing angiomatoid nodular transformation of the spleen with pathologic correlation. Nine patients with surgically resected and pathologically confirmed sclerosing angiomatoid nodular transformation were included in the study. Clinical history was reviewed to determine patient demographics and symptoms at presentation. Gross pathologic, histologic, and immunohistochemical findings were recorded. CT (n = 9) and MRI (n = 4) examinations were evaluated for lesion shape and margins, intrinsic characteristics, and enhancement pattern. Patients included were six women and three men, with a mean age of 41.2 years. Pathologic features of sclerosing angiomatoid nodular transformation included multiple angiomatous nodules in a radiating pattern with a central stellate fibrous scar and evidence of hemosiderin deposition. On imaging, the lesions were solitary and round, 78% having a lobulated margin. They were heterogeneously hypoenhancing during the arterial and portal venous phases of contrast-enhanced CT or MRI, with peripheral enhancing radiating lines in 88% of lesions. They showed progressive enhancement and were isoenhancing or hyperenhancing in the delayed phase. A hypoenhancing central scar was shown on imaging in 22% of lesions. All lesions were hypointense on T2-weighted images. Sclerosing angiomatoid nodular transformation shows characteristic CT and MRI findings reflecting the underlying pathology. Typical features are a solitary, round, lobulated mass with early peripheral enhancing radiating lines and progressive enhancement of the angiomatous nodules; delayed enhancement of the fibrous tissue; and hypo-intense T2 signal intensity from hemosiderin deposition.

Predictors of Dysplastic Nodule Diagnosis in Patients With Liver Cirrhosis on Unenhanced and Gadobenate Dimeglumine–Enhanced MRI With Dynamic and Hepatobiliary Phase

The purpose of this article is to assess whether unenhanced and gadobenate dimeglumine-enhanced MRI with dynamic and hepatobiliary phase may predict the diagnosis of dysplastic nodules in patients with liver cirrhosis. We retrospectively analyzed 75 cirrhotic patients (47 men and 28 women; mean [± SD] age, 55 ± 12 years) with 82 hepatocellular nodules, including histology-proven dysplastic nodules (n = 25; diameter, 1-3 cm) and hepatocellular carcinomas (n = 57; diameter, 2-3 cm) scanned by MRI before and after gadobenate dimeglumine injection during hepatic arterial phase (HAP), portal venous phase (PVP), equilibrium phase, and hepatobiliary phase. Nodule T1 and T2 intensities before contrast agent injection and nodule HAP, PVP, equilibrium phase, and hepatobiliary phase intensities were compared with the adjacent liver. Univariate and multivariate logistic regression analysis was conducted to assess how the nodule could predict dysplastic nodule diagnosis. Some imaging findings were independent predictors of dysplastic nodule diagnosis-namely, nodule T2 isohypointensity (odds ratio [OR], 12.28; 95% CI, 3.88-38.82), T1 isohyperintensity (OR, 26.74; 95% CI, 7.53-94.90), HAP isohypointensity (OR, 97.16; 95% CI, 20.06-470.49), PVP-equilibrium phase isohyperintensity (OR, 20.53; 95% CI, 5.36-78.62), and hepatobiliary phase isohyperintensity (OR, 119.6; 95% CI, 21.59-662.40). Nodule T2 and HAP isohypointensity (OR 31.47; 95% CI, 7.88-125.58), nodule T2 isohypointensity and hepatobiliary phase isohyperintensity (OR, 28.77; 95% CI, 7.79-106.19), nodule T1 isohyperintensity and HAP isohypointensity (OR, 17.22; 95% CI, 4.85-61.14), and nodule T1 and hepatobiliary phase isohyperintensity (OR, 19.39; 95% CI, 5.38-69.90) were also predictors of dysplastic nodule diagnosis. The combination of nodule appearance on T2-weighted MRI and nodule enhancement after gadobenate dimeglumine injection may predict dysplastic nodule diagnosis in patients with liver cirrhosis.

Primed Infusion with Delayed Equilibrium of Gd.DTPA for Enhanced Imaging of Small Pulmonary Metastases

ObjectivesTo use primed infusions of the magnetic resonance imaging (MRI) contrast agent Gd.DTPA (Magnevist), to achieve an equilibrium between blood and tissue (eqMRI). This may increase tumor Gd concentrations as a novel cancer imaging methodology for the enhancement of small tumor nodules within the low signal-to-noise background of the lung.MethodsA primed infusion with a delay before equilibrium (eqMRI) of the Gd(III) chelator Gd.DTPA, via the intraperitoneal route, was used to evaluate gadolinium tumor enhancement as a function of a bolus injection, which is applied routinely in the clinic, compared to gadolinium maintained at equilibrium. A double gated (respiration and cardiac) spin-echo sequence at 9.4T was used to evaluate whole lungs pre contrast and then at 15 (representative of bolus enhancement), 25 and 35 minutes (representative of eqMRI). This was carried out in two lung metastasis models representative of high and low tumor cell seeding. Lungs containing discrete tumor nodes where inflation fixed and taken for haematoxylin and eosin staining as well as CD34 staining for correlation to MRI.ResultsWe demonstrate that sustained Gd enhancement, afforded by Gd equilibrium, increases the detection of pulmonary metastases compared to bolus enhancement and those tumors which enhance at equilibrium are sub-millimetre in size (<0.7 mm2) with a similar morphology to early bronchoalveolar cell carcinomas.ConclusionAs Gd-chelates are routinely used in the clinic for detecting tumors by MRI, this methodology is readily transferable to the clinic and advances MRI as a methodology for the detection of small pulmonary tumors.

Evaluation of Indeterminate Pulmonary Nodules with Dynamic MR Imaging

We prospectively assessed whether enhancement characteristics on dynamic magnetic resonance (MR) imaging could distinguish indeterminate pulmonary nodules. We evaluated 51 pulmonary nodules in 51 consecutive patients (11 female, 40 male; mean age, 64 years) using dynamic MR images acquired at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 120, 150, 180, 210, 240, 360, 480, 600, 720, and 840 s following injection of contrast material. We prospectively evaluated morphologic enhancement patterns, peak rate, time to peak enhancement, steepest slope, and washout of nodules and analyzed statistics to determine any differences between MR parameters, patient age, tumor size, and final diagnosis. We found 25 malignant, 12 active inflammatory, and 14 benign nodules. Nodule diameter was significantly larger for malignant than nonmalignant, and benign nodules (P≤0.01). Patients with malignant nodules were significantly older than those with nonmalignant (P=0.01) and active inflammatory (P=0.02) nodules. However, morphologic enhancement patterns, peak rate, time to peak enhancement, steepest slope, and washout characteristics at 2, 4, 8, and 12 min showed no significant difference between malignant and nonmalignant nodules and among malignant, active inflammatory, and benign nodules. Prospective assessment of dynamic MR images demonstrated their inadequacy for distinguishing indeterminate pulmonary nodules.