Harsh Kandpal

Respiratory-Triggered Versus Breath-Hold Diffusion-Weighted MRI of Liver Lesions: Comparison of Image Quality and Apparent Diffusion Coefficient Values

OBJECTIVE The purpose of our study was to compare respiratory-triggered and breath-hold diffusion-weighted liver MRI and to assess the agreement in the apparent diffusion co-efficient (ADC) values between the two sequences. MATERIALS AND METHODS Forty-eight patients (27 men, 21 women; mean age, 45.2 years) with focal liver lesions underwent respiratory-triggered and breath-hold diffusion-weighted MRI (DWI) in addition to routine MRI. Both sequences had identical imaging parameters except for signal averages, which were 6 in respiratory-triggered and 2 in breath-hold sequences. A total of 92 lesions (maximum of three lesions per patient; 37 benign, 55 malignant) were evaluated. Lesions were confirmed by typical imaging appearance, histopathology, or follow-up. Signal-to-noise ratio (SNR) of the liver, contrast-to-noise ratio (CNR), and relative contrast ratio of the lesions were measured in each DWI sequence and were statistically compared using the Mann-Whitney U test. The ADC values of normal liver and each category of liver lesions in the two sequences were compared for agreement using Pearsons coefficient and reliability analysis scale. RESULTS The SNR of the normal liver was significantly better on respiratory-triggered DWI than on breath-hold DWI. The mean CNR of metastases, hepatocellular carcinomas, and abscesses was significantly better in the respiratory-triggered DWI than in the breath-hold DWI sequences. The ADC values of liver and focal lesions measured by the two techniques showed good agreement. The SDs of the ADC values of normal liver were similar in the two sequences. CONCLUSION Respiratory-triggered DWI should be preferred over breath-hold DWI for the evaluation of focal liver lesions because it provides better image quality and SNR without any compromise in the calculated ADC values.

Imaging the Inferior Vena Cava: A Road Less Traveled

A broad spectrum of congenital anomalies and pathologic conditions can affect the inferior vena cava (IVC). Most congenital anomalies are asymptomatic; consequently, an awareness of their existence and imaging appearances is necessary to avoid misinterpretation. Imaging also plays a central role in the diagnosis of Budd-Chiari syndrome secondary to membranous obstruction of the intrahepatic IVC. Primary malignancy of the IVC is far less common than intracaval extension of malignant tumors arising in adjacent organs, and imaging can accurately help determine the presence and extent of tumor thrombus, information that is crucial for surgical planning. However, the radiologist should be aware that artifactual filling defects at computed tomography and magnetic resonance imaging can mimic true thrombus in the IVC and must be able to differentiate true from pseudo filling defects. Other imaging findings such as flat IVC and early enhancement of the IVC are useful in limiting the differential diagnosis. Familiarity with the imaging features of the various congenital and pathologic entities that can affect the IVC is paramount for early diagnosis and management.

In Vivo Proton Spectroscopy of Giant Cell Tumor of the Bone

OBJECTIVE The proton MR spectroscopic finding of elevated choline has been reported to be useful in the differentiation of malignant from benign musculoskeletal tumors. This study was designed to evaluate the MR spectroscopy features of giant cell tumor (GCT) of the bone, primarily to determine whether the presence of choline is a frequent occurrence in these tumors and whether MR spectroscopy features can be correlated with clinical, radiologic, and histopathologic findings. SUBJECTS AND METHODS MRI, dynamic contrast-enhanced MRI, and proton MR spectroscopy were performed in 33 patients with bone tumors on a 1.5-T MR scanner. Of these, 12 patients who had GCT of the bone form the subject material for this study. Dynamic contrast-enhanced MRI and single-voxel proton MR spectroscopy were performed after preliminary evaluation with radiography. Patients were divided into two groups, those with elevated choline levels and those without a choline peak on MR spectroscopy. The clinical and radiologic features, including the Campanacci stage and dynamic MRI findings, were compared in these two groups. Core biopsy was performed in all patients, and in 10 of 12 patients, histopathologic evaluation of the postoperative resected specimen was also performed. RESULTS Although all 12 tumors were benign on histopathology, four had elevated choline levels. Of these, three (75%) had an aggressive radiographic appearance (Campanacci stage 3). As opposed to this, only three of the eight (37.5%) tumors without a choline peak had an aggressive radiographic appearance. Except for a single case, all tumors showed early enhancement and washout of contrast material on dynamic MRI. CONCLUSION The results of this study indicate that GCT of bone may show raised choline levels on proton MR spectroscopy. This finding is not an indicator of malignancy in these tumors.

Combined transmesocolic and left paraduodenal hernia: barium, CT and MRI features

Internal hernia is difficult to diagnose clinically because the symptoms are often non-specific. Although this entity is an uncommon cause of small-bowel obstruction, prompt diagnosis is essential for a favorable outcome. We report the barium, CT and MRI features of a rare case of non-obstructing combined transmesocolic and left paraduodenal hernia.

Rheumatoid Arthritis: Spectrum of Computed Tomographic Findings in Pulmonary Diseases

Rheumatoid arthritis (RA) is a common systemic disease that manifests as inflammatory arthritis of multiple joints. Interstitial lung disease (ILD) is the most common manifestation of rheumatoid lung disease. The ILDs associated with RA are diverse and it is very important for the general radiologist to differentiate one from another. There are many other pulmonary diseases apart from ILD. These are associated with a wide spectrum of morphologic changes with substantially different prognoses. The diagnosis of most of these diseases is by clinicoradiological correlation and some of them need pathologic correlation. High-resolution computed tomography helps to characterize and determine the extent of ILD in RA. When interpreting the high-resolution computed tomography of the chest in RA, the radiologist should be familiar with the findings in each entity and comment on activity of the disease, which helps in assessing the prognosis and need for active intervention. This pictorial essay reviews the spectrum of pulmonary diseases in RA and their differential diagnosis.

Imaging spectrum of pediatric orbital pathology: A pictorial review

A wide spectrum of pediatric orbital disorders can occur in the pediatric age group. Cross-sectional imaging plays an important role in the diagnosis and management of these patients. We reviewed our imaging record and collected representative cases of pediatric orbital pathology. The purpose of this pictorial essay is to illustrate the imaging features of various orbital lesions encountered in children.

Cavernous sinus thrombophlebitis causing reversible narrowing of internal carotid artery

Neurology India | Jan-Feb 2009 | Vol 57 | Issue 1 Figure 2: Axial contrast-enhanced T1W MRI (a) shows diffuse enhancement of the wall of the right intra-petrous ICA (arrow). Ethmoid and sphenoid sinusitis is also seen. 3D contrast-enhanced MR angiogram (b) shows long segment narrowing of the right ICA (arrow). The left ICA is normal (black arrow) Cavernous sinus thrombophlebitis causing reversible narrowing of internal carotid artery

Pituitary stalk duplication with intrasellar dermoid and herniation of the third ventricle

An 11-year-old boy with short stature (height 111 cm) had a weight of 19 kg and a bone age of 5 years. There were low levels of all the anterior pituitary hormones, but no evidence of central diabetes insipidus. Coronal MR images (Fig. 1) showed duplication of the pituitary infundibulum (arrowheads) and hypothalamus (arrows). A well-defined T1-hyperintense lesion consistent with a dermoid (star) was seen within the sella between the duplicated stalks. Sagittal images (Fig. 2) showed intrasellar and trans-sellar herniation of the third ventricle (star). The anterior pituitary was single; the posterior pituitary was normal.

Craniodiaphyseal dysplasia: An unusual cause of recurrent dacryocystitis

We describe a rare syndrome characterized by severe craniofacial hyperostosis, sclerosis, obliteration of paranasal sinuses and foramina of skull base, in a 10-year-old female child who presented with abnormal facial features and recurrent dacryocystitis due to narrowing of nasolacrimal duct.

Langerhans cell histiocytosis of pituitary stalk.

A four-year-old male child presented with increased Typically the lesions are round or oval-shaped with wellurine output and excessive thirst for eight months. On defined margins and bevelled edge. Individual lesions examination he had multiple scalp swellings with mild may coalesce giving a geographic appearance to the skull hepatosplenomegaly. Urine specific gravity was decreased suggestive of diabetes insipidus. Skull radiograph revealed multiple well-defined geographic lytic lesions in the calvarium with bevelled margins [Figure 1]. On MR examination of sella, the posterior pituitary bright spot was not seen on T1W image [Figure 2]. The pituitary stalk was thickened and showed uniform enhancement [Figure 3]. The characteristic radiographic feature of skull lesions, MRI findings and hepatosplenomegaly strongly suggested the possibility of Langerhans cell histiocytosis (LCH) which was confirmed on bone marrow biopsy. LCH is a wide-spectrum disease characterized by proliferation of abnormal histiocytes. It encompasses three classical clinical syndromes which in increasing order of severity are: eosinophilic granuloma (solitary bone lesion), Hand-Schuller-Christian disease (skull lesion, exophthalmos and diabetes insipidus) and Figure 2: T1W sagittal image. The bright spot of the posterior Letterer-Siwe disease (multisystemic rapidly progressive pituitary is not seen and the pituitary stalk is thickened. Isointense form). The skull bones are most commonly involved. soft tissue mass is seen in the clivus and sphenoid bone