Diagnostic Accuracy of Hyperacute MRI in Prediction of Residual Tumor and Progression in Pituitary Macroadenomas Abstract Id: IRIA – A Retrospective Study

Aims and Objectives:  Detection of residual tumor for follow up in patients with a pituitary macroadenoma who undergo surgery  Distinguish post operative bed contents on post op imaging  Imaging for early detection of recurrence

Selection Criteria  Any patient with pituitary macroadenoma (size >1cm) who presented to our institution between a period of 1 year (July 2013 and June 2014) for whom pre operative and post operative hyperacute (within 6 hours post op) MRI brain were done and follow up (6 months and later) MRI brain was done / planned for

Materials and Methods:  Total number of patients = 46  MRI sequences used:  Preoperative MRI - T2W, FLAIR, T1W and post contrast T1W sequences  Hyperacute MRI - T2W, FLAIR and T1W sequences  Follow up MRI - T2W, FLAIR, T1W and post contrast T1W sequences

Materials and Methods:  Availability of pre operative MRI – all patients  Availability of hyperacute MRI – all patients  Availability of follow up MRI – 26 patients  Tumor volumes were calculated using the tool provided in Centricity – PACS

Results - Demographics  Gender  Age: between 20 and 62 years (mean 41 years)

Tumor Functional Characteristics  91.67% of non functioning macroadenomas were Hardy grade C and higher

Hardy Grade A Post gadolinium T1W coronal & sagittal sections showing a heterogeneously enhancing intrasellar pituitary macroadenoma Case1:44 year male with coarsening of facial features Fig. 1A Fig. 1B

Hardy Grade B Post gadolinium T1W coronal & sagittal sections showing a homogeneously enhancing sellar -suprasellar lesion, with extension into the right cavernous sinus Case 2:40 year old female with headache Fig. 2A Fig. 2B

Hardy Grade C Post gadolinium T1W coronal & sagittal sections showing a homogeneously enhancing sellar-suprasellar mass with a small superiorly placed cystic component reaching upto the floor of the third ventricle Case 3: 22 year old male with acromegaly, visual loss Fig. 3AFig. 3B

Hardy Grade D Post gadolinium T1W coronal & sagittal sections showing a homogeneously enhancing sellar-suprasellar lesion extending superiorly into the basifrontal region and into the left cavernous sinus Case 4:40 year old male with headache, visual loss Fig. 4A Fig. 4B

Giant Macroadenoma 9 of 46 pituitary tumors were giant macroadenomas measuring > 5 cm, few of which were found to be eroding and extensively invading the skull base Post gadolinium T1W coronal sections showing a large homogeneously enhancing sellar-suprasellar mass measuring ~5.5 cm in the anteriposterior dimension Fig. 5A Fig. 5B Fig. 5C Fig. 5D

Extension into Cavernous Sinus Extension into cavernous sinus, though commonly seen with Hardy grade C and D tumors was not exclusive to them Surgical approach being difficult, this was the most common site where residual tumor was found in the hyperacute MRI and also the most common site for tumor recurrence seen on the subsequent follow up MRI Preop MRI, T1W coronal sections showing dumb bell shaped sellar -suprasellar mass extending into bilateral cavernous sinuses 6 month follow up MRI T1W coronal sections showing residual tumor in the right cavernous sinus Fig. 6B Fig. 6A

Hyperacute MRI: Postop Bed Appearance Heterogeneity in the post op bed was found to be contributed by  Hemorrhage  Edema  Hemostatic material (Surgicel in all cases & both surgicel and gelfoam in 5 cases)  Graft material (fat/fascia) used to repair CSF leaks (8 cases) or large dural defects Hyperacute MRI of a 61 year old male who had a Hardy grade C pituitary macroadenoma. Intraoperatively surgicel was used to achieve hemostasis. Fig. 7A Fig. 7B

Hyperacute MRI: Postop Bed Appearance A. Preop, B. Hyperacute, C. 6 month follow up MRI of a 62 year old male with Hardy grade C macroadenoma that was surgically excised While the hyperacute MRI appeared to show a large, heterogeneous residual sellar – suprasellar tumor with areas of haemorrhage within, the follow up MRI did not show any evidence of residual tumor. Fig. 8AFig. 8BFig. 8C

Hyperacute MRI: Directive in Reoperation  5 of 46 cases in which significant residual tumor (>50%) was found in the hyperacute MRI, in the sella and suprasellar regions underwent re-exploration and tumor excision / stereotactic radiotherapy.  None of these patients have presented with tumor recurrence so far * * * * Residual Tumor Fig. 9B Fig. 9C Fig. 9D * Fig. 9A

In conclusion  Hyperacute MRI is useful to predict re-surgery if required  Residual tumor was most commonly seen in the cavernous sinus region  Only on comparison with the preoperative MRI the amount or nature of the residual tissue being imaged can be truly ascertained

Clinical Relevance  Hyperacute MRI is a very good diagnostic tool in the post op evaluation of residual tumor and to predict recurrence in pituitary macroadenomas

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