Cirsoid aneurysm of scalp

This young guy presented with pulsatile swelling in the scalp

O/E continuous machinery murmur could be heard over the swelling

Diagnosis Cirsoid aneurysm of scalp

Exploration of the pulsatile mass with visualisation of the feeding artery done and the ligation of the feeding vessel with excision of the dilated vessels done

Fourth Ventricle tumor

Cerebelar tonsil retracted

Brain stem visualised nicely

PICA is seen in the operating field

midline incision from inion to level of C2

Occiput and 1st dorsal arch and 2nd cervical spine visualised

This is a case of 16 yrs old female presenting with headache , dizziness for 1 yr .

Case was operated and a firm mass was visualised in fourth ventricle reaching up t0 mid brain .

Suboccipital craniectomy was done and 1st dorsal arch also removed Y shaped incision over dura . Cerebellar tonsil retracted and vermis exposed and retracted tumor mass was visualised and total resection of tumor from ventricular bed along with its extension achieved .

Cerebello pontine angle Tumor

Cerebellopontine angle is the region where petrosal surface of cerebellum wraps around the pons and upper medulla with the middle cerebellar peduncle being its floor .

CPA is formed by superior and inferior limbs of cerebellopontine fissure with the apex oriented laterally .

It is the site for 8 to 10 % of intracranial tumor.

Most common tumor at this area are Vestibular Schwannoma (80 to 90 %) , Meningioma and Epidermoid cyst.

Anatomy of CPA can be conceptualized by breaking down various neurovasculature into 3 complexes .

Upper complex consists of V CN , superior cerebellar artery and petrosal vein.

Middle coplex consists of VII and VIII CN complex and Anterior Inferior Cerebellar Artery (AICA) and its surgically important 3 branches internal auditary artery ( labyrinthine artery ) , the recurrent perforating artery and subarcuate artery .

Lower complex consists of IX X XI CN complex and Posterior Infereior cerebellar artery. ( PICA)

Brain Abscess Or Tumor

Sometimes its so confusing to distinguish brain abscess and brain tumor on scans . Ring enchancing lesion on scan.

MRI spectroscopy helps to distinguish between two

What is Magnetic Resonance Spectroscopy?

Simply put, MRS is a quantitative method of display of non-aqueous proton signals that correspond to certain biological molecules in the brain.
Magnetic resonance imaging (MRI) uses water protons to create images. Very sophisticated and detailed images of the brain are produced based on the fact that different tissues within the brain have different water content. The hydrogen nuclei (protons) that are not in water (non-aqueous protons) are distributed throughout the hundreds of biologically significant molecules of the living brain. These molecular radio-signals are not visible on standard MR images because they are overwhelmed by the high signal derived from the aqueous protons. The non-aqueous molecules each has a unique radio-frequency specific to the chemical itself and distinct from the frequency of water protons. The amplitude or strength of these radio-frequencies is dependent on their concentration in the volume of interest, each at their discrete radio-frequence position. This allows a graph to be displayed that shows the relative peaks of amplitude for each of several biological molecules. These peaks are more readily detected and displayed if the signal from aqueous protons is suppressed.

What is MR Spectrum?
The "spectrum" is a graph of the relative concentrations of these molecules based on their discrete radio-frequency signal, which is shifted away (chemical shift) from the water signal the MRI uses. A high peak means that the molecule at that RF location exists in greater concentration than an adjacent low peak. To be precise, it is the area under the peak that is relevant. Applying appropriate calibrations, the concentration of a given metabolite is calculated from the peak area. The peak locations correspond to specific molecules such as glucose, creatine, lactate etc, however peaks from non-identical molecules may overlap. In practice, the peak position identifies the brain metabolite. The combination of peak locations (chemical shift compared to water) and heights provides a biochemical fingerprint of the volume of interest (VOI).

MRS demonstrate increase choline peak in case of tumors while abscess dont whereas abscess demonstrate acetate and aminoacid resonance