Ratni B. Gujral

Intracranial tuberculomas: MRI signal intensity correlation with histopathology and localised proton spectroscopy.

In seven cases of intracranial tuberculomas showing different signal intensities on MRI (five characteristic and two nonspecific), detailed histopathological examination was performed to look for number of macrophages, fibrosis, gliosis, degree of inflammatory cellular infiltrate, and type of caseation. The granulomas showing more macrophages, fibrosis and gliosis appeared hypointense on T2-weighted images. Tuberculomas showing minimal macrophages, marked cellular infiltration, and minimal fibrosis appeared hyperintense on T2-weighted images. Lesions showing similar signal intensity on T2-weighted images showed variation in the amount of macrophages, cellular infiltrates, maturity and fibrosis. Trace element estimation was done (iron, copper, and magnesium) in two of these lesions appearing hypointense on T2 and two normal brain samples; these were significantly lower in tuberculoma compared to normal brain tissue. Localised proton spectroscopy was performed in two hypointense lesions which showed marked increase in peaks in the region of mobile lipids (1.28 ppm) compared to normal brain parenchyma. It is concluded that the signal intensity of the lesions is dependent on the number of macrophages, fibrosis and cellular infiltrates. In addition increased lipid contents in the tuberculoma also contribute to the hypointensity on T2-weighted images.

Brain metabolite changes on in vivo proton magnetic resonance spectroscopy in children with congenital hypothyroidism

Localized in vivo proton magnetic resonance spectroscopy and imaging were performed in five children with untreated congenital hypothyroidism to look for biochemical markers of abnormal myelin and neuronal development. The patients had high levels of choline-containing compounds, which returned to normal with euthyroidism. These metabolic alterations may reflect blocks in myelin maturation that are reversible by thyroid hormone replacement throughout childhood.

The magnetic resonance renogram in renal transplant evaluation using dynamic contrast-enhanced MR imaging.

To assess the role of the dynamic gadolinium DTPA (Gd-DTPA) magnetic resonance (MR) renogram in differentiating various causes of renal allograft dysfunction, contrast-enhanced MR imaging studies were performed in 5 normal renal allografts, 5 patients with acute rejection (AR), and 7 patients with cyclosporine nephrotoxicity. Time-versus-signal intensity (SI) curves were plotted. Normal renal allografts showed a rapid increase and slow decay, with a definite peak in cortical (CX) SI curves (peak mean signal intensity (Amax 338.6 +/- 46.5). The outer medullary (OM) (Amax 306.5 +/- 59) and inner medullary (IM) (Amax 263.4 +/- 47.4) curves did not show a definite peak. The OM curve slowly reached a steady state and caught up with the CX curve. AR episodes were characterized by a blunted uprise and delayed peak of CX (Amax 180 +/- 70.9) and a low-amplitude vascular phase with a slow constant uprise of the inner medullary curve (Amax 120.35 +/- 42.4). The OM signal intensity curve (Amax 150.73 +/- 78) failed to catch up with the CX curve. The maximum amplitude of SI curves in CsA-induced allograft dysfunction were low, with no definite peak, and CX, OM, and IM curves ran parallel to each other with a constant gap. Dynamic Gd-DTPA, MR imaging is a noninvasive technique that shows distinct characteristics in acute rejection, cyclosporine nephrotoxicity, and normally functioning renal allografts.

Cine MR voiding cystourethrogram in adult normal males

Cine voiding cystourethrogram was performed in 15 normal subjects using T1-weighted Turbo FLASH sequence. It showed the sequence of emptying of bladder, detrusor muscle contraction, opening of the sphincters, and various parts of urethra. It was found to be a good noninvasive test to study the dynamics of lower urinary tract without disturbing the state of the physiology.

Acute bilateral ophthalmoplegia secondary to metastatic prostatic carcinoma. Demonstration on magnetic resonance imaging.

We report an unusual case of acute bilateral ophthalmoplegia secondary to bilateral cavernous sinus metastasis from prostatic adenocarcinoma. The lesion was demonstrated with magnetic resonance imaging.

Treatment of Recurrent Posterior and Bulbar Urethral Strictures with Expandable Metallic Stents

PURPOSEnThe role of expandable metallic Z stents (non-mesh) in the treatment of recurrent posterior and bulbar urethral strictures was evaluated.nnnPATIENTS AND METHODSnSeven men with recurrent posterior/bulbar urethral strictures underwent balloon angioplasty followed by insertion of two stents in tandem. Retrograde urethrography, micturating cystourethrography, and urodynamic evaluation of these patients was done initially.nnnRESULTSnSuccessful dilation and placement of stents was possible in all cases. In one patient slight proximal migration of the stent occurred; terminal dysuria in this patient necessitated stent extraction. In two other patients near total occlusion of the stent by an exuberant fibrous reaction occurred and this open urethroplasty in the other. Immediate postprocedure urethrography and urodynamic evaluation showed significant improvement. Five patients continue to show a satisfactory clinical urodynamic response. The follow-up period in this patient group ranged from 5 months to 1 year.nnnCONCLUSIONnShort-term response (5 months to 1 year) in patients with posterior/bulbar urethral strictures treated with Z stents appears promising. However, the efficacy of the procedure on a long-term basis requires further follow-up and evaluation.