Localization of Postoperative Cerebrospinal Fluid Rhinorrhea by Fusion of Radionuclide SPECT Cisternography and MR Images

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1 Localization of Postoperative Cerebrospinal Fluid Rhinorrhea by Fusion of Radionuclide SPECT Cisternography and MR Images Su-Mei Chen 1, Kun-Chou Chin 2, Chia-Lung Liu 1 1 Division of Nuclear Medicine, Taipei City Hospital, Renai Branch, Taipei, Taiwan 2 Division of Nuclear Medicine, Min-Sheng General Hospital, Taoyuan, Taiwan The purpose of this case report is to demonstrate the utility of SPECT cisternography-mri fused imaging in the diagnosis of postoperative cerebrospinal fluid (CSF) leakage. A 55-year-old woman had history of surgical interventions for a pituitary tumor. Three years after, she was suspected clinically with CSF leakage. Radionuclide cisternography was performed with intrathecal lumbar injection of 99m Tc-DTPA and SPECT images were acquired at 24 h. The SPECT cisternography was registered with previous performed MRI to obtain fused images. Planar and SPECT cisternography revealed accumulation of the tracer near the skull base. The SPECT cisternography-mri fused imaging provided precise anatomic localization of CSF leak. Fusion of SPECT and MRI images as exemplified in the present report could provide substantial informational and diagnostic benefit in selected cases. Key words: cerebrospinal fluid leak, radionuclide cisternography, single photon emission tomography, image fusion Ann Nucl Med Sci 2006;19: Introduction Patients with cerebrospinal fluid (CSF) leaks present a diagnostic challenge to both clinicians and radiologists. Preoperative assessment of patients with CSF rhinorrheas or otorrrheas requires localization of an anatomic defect. Various combinations of planar skull films [1] and computed tomography (CT), intralumbar injection of dyes [2], contrastenhanced CT cisternography, radionuclide cisternography [3], overpressure radionuclide cisternography [4] and magnetic resonance (MR) cisternography [5] have been used in the diagnosis of these patients. Radionuclide cisternography has been used for the detection of rhinorrhea since 1956 [6]. A previous report indicated that it is very difficult to visualize leaks from the subarachnoid space into the nasal cavity by means of conventional planar scintigraphy [7]. Single photon emission computed tomography (SPECT) cisternography following lumbar injection of radionuclide was proposed as a valuable diagnostic tool for evaluation of small intermittent leaks in the difficult area of the cribriform plate [8] and was superior in the delineation of basal cisterns [9]. We report here a case of postoperative CSF leakage where SPECT cisternographymagnetic resonance image (MRI) fused images demonstrated the precise location of a CSF leak. Received 7/21/2006; revised 8/11/2006; accepted 8/15/2006. For correspondence or reprints contact: Su-Mei Chen, M.D., Division of Nuclear Medicine, Taipei City Hospital, Renai Branch, 10 Section 4, Renai Road, Daan District, Taipei 106, Taiwan. Tel: (886) ext. 5117, Fax: (886) , lucky@tpech.gov.tw Case Report A 55-year-old woman had history of surgical interventions for a pituitary tumor with a ventricle-peritoneal shunt (V-P shunt) placed at the lateral ventricle via the right frontal

2 Chen SM et al Figure 2. Radionuclide cisternography was performed after intrathecal injection of 99m Tc-DTPA. (A) The planar image at 3.5 h revealed focal areas of faint activity below the skull base (arrow). (B) The activity (arrow) became more intense with image delayed at 24 h. Figure 1. CT scan revealed destruction of the sellar floor (arrow is pointing to the completely destructed posterior clinoid process). region for three years. MRI performed 2 years later showed post-operative change at the infrasellar and sellar regions with residual tumor at left cavernous sinus and paracavernous regions. She was hospitalized for headache with progressive drowsy consciousness, urinary incontinence, and gait disturbance. CT revealed extensive pneumocephalus in the subarachnoid space and ventricles as well as destruction of the sellar floor (Figure 1). However, there was no complaint of gross nasal discharge. Radionuclide cisternography was requested to detect CSF leak. Therefore, we performed radionuclide cisternography with intrathecal lumbar injection of 740 mbq 99m Tcdiethylenetriaminepentaacetic acid (DTPA). The planar images at 3.5 h revealed focal areas of faint activity below the skull base that became more intense with images delayed at 24 h (Figure 2). The SPECT cisternography was acquired with subsequent 3D surface rendering and registered with MRI performed three months prior to this examination to obtain fused images. We used the image fusion software tool on our Pegasys TM workstation (ADAC, USA) to overlay SPECT cisternography onto the computer reformatted MRI image series with visual alignment in three dimensions. The Figure 3. The SPECT cisternography-mri fused images (left: transverse view; right: sagittal view) showed very distinct pathological activity (arrow) stretching inferiorly from the cranial base and into the right nasal cavity. MRI series were used instead of CT series because our CT image set cannot be reformatted by the Pegasys TM software to be a volume image for three-dimension alignment. The SPECT cisternography-mri fused images provided precise anatomic localization of CSF leak in the right nasal cavity and depicted its close relationship with the subarachnoid space around the right sellar area (Figure 3). In the night after the completion of SPECT study, the patient had rhinorrhea. Intermittent rhinorrhea had been noted for several days but only supportive treatment was given. Unfortunately, the patient expired due to CNS infection 6 weeks later. Discussion Defects in the floor of the anterior cranial fossa can lead Ann Nucl Med Sci 2006;19: Vol. 19 No. 4 December

3 SPECT MR SPECT cisternography and MRI fusion image of CSF leakage to leakage of cerebrospinal fluid (CSF) into the nasal cavity. Iatrogenic skull-base defects usually occur following functional endoscopic sinus surgery and neurological surgery [10]. With the advent of surgery of the anterior skull base and endoscopic sinus surgery and because of the nature of trauma to this area, the number of patients with CSF rhinorrhea has increased. Because of the nature of the nasal cavity and its exposure to the rest of the upper aerodigestive tract, communication with the intracranial contents can lead to meningitis and other intracranial complications. This presents a serious and sometimes lethal medical problem. High-resolution coronal and axial computed tomography (HRCT) is useful in nearly all cases, independent of leak activity. It provides important bony detail that is useful in the surgical approach and helps identify and localize the skullbase defect. Unfortunately, it does not establish the diagnosis of CSF leak because bony defects may be present but not be actively leaking CSF [10]. HRCT cisternography with iopamidol or iohexol contrast is now widely available, with relatively high sensitivity of 81%-87% for CSF leak localization, and it is currently the first-line choice for radiographic evaluation [11]. However, the CT cisternography is limited in that the leak is not detected unless there is active drainage during the procedure [12]. MRI typically is not recommended in the evaluation of a CSF leak because it does not demonstrate bony defects very well. However, a heavy T2- weighted image can reveal a brisk CSF leak [13]. On the basis of signal intensity differences, MRI could not distinguish between CSF leakage and postoperative scarring. The nuclear medicine study is advantageous for symptomatic patients with small intermittent CSF leaks because it is performed over a longer time, thus increasing the chance of CSF leak detection [14]. Previous studies suggested that radionuclide cisternography may be reserved for patients with multiple fractures or postoperative defects [15]. SPECT cisternography after intralumbar injection of 123 I-albumin or 111 In-DTPA or 99m Tc-DTPA were recently proposed as a valuable diagnostic tool for evaluation of small intermittent leaks in the difficult area of the cribriform plate [8]. Different tracers can be used including radioiodine serum albumin (RISA), 111 In-DTPA, 99m Tc-human serum albumin, and 99mTc-pertechnetate. Another option is to introduce nasal pledgets in various high risk areas. These pledgets then can be analyzed for the presence of the tracer. Although radionuclide studies have proven to be a sensitive and accurate method of examination for CSF leak [16-19], the utility of these studies was diminished due to lack of structural delineation, making precise anatomic localization of CSF leak difficult. The significance of adding anatomic information from CT to nuclear medicine data is well recognized in the oncology community and has led to the development of numerous algorithms aimed at coregistering functional and anatomic images [20-22]. Over the years, commercially available software packages of registration allow versatility in the choice of modalities and facilitate retrospective and selective application. Software image registration has been applied in neurologic, oncologic, and cardiac applications for MRI, CT, positron emission tomography (PET), and SPECT [23-25]. Our case demonstrated the usefulness of SPECT cisternography in detecting intermittent CSF leaks. In addition, we used registration software to fuse the SPECT cisternography with MRI images, which provided precise anatomic localization of CSF leak, although MRI cannot demonstrate bony defects very well. The use of SPECT cisternography and anatomical image fusion may overcome the disadvantage of lack of structural delineation of SPECT cisternography and provide substantial informational benefit for diagnosis of CSF leak in selected cases. References 1. Lantz EJ, Forbes GS, Brown ML, Laws ER Jr. Radiology of cerebrospinal fluid rhinorrhea. Am J Roentgenol 1980;135: Calcaterra TC. Diagnosis and management of ethmoid cerebrospinal rhinorrhea. Otolaryngol Clin North Am 1985;18: Front D, Penning L. Occult spontaneous cerebrospinal fluid rhinorrhoea diagnosed by isotope cisternography. Neuroradiology 1971;2: ;19:

4 Chen SM et al 4. Curnes JT, Vincent LM, Kowalsky RJ, McCartney WH, Staab EV. CSF rhinorrhea: detection and localization using overpressure cisternography with 99m Tc-DTPA. Radiology 1985;154: Nicklaus P, Dutcher PO, Kido DK, Hengerer AS, Nelson CN. New imaging techniques in diagnosis of cerebrospinal fluid fistula. Laryngoscope 1988;98: Crow HJ, Koegh C, Northfield DWC. The localization of cerebrospinal fluid fistulae. Lancet 1956;271: Schicha H, Voth E, Emrich D. Detection of occult and intermittent rhinorrhoea using 111 In-DTPA. Eur J Nucl Med 1985;11: Nielsen JT, Andersen K, Nielsen BV, Marqversen J, Jensen F. Detection of rhinorrhoea by cisternography in combination with single photon emission tomography, following lumbar injection of iodine-123-labelled albumin. Eur J Nucl Med 1992;19: Henkes H, Huber G, Hierholzer J, et al. Radionuclide cisternography: SPECT-and 3D-technique (abstract). Radiologe 1991;10: Schlosser RJ, Bolger WE. Nasal cerebrospinal fluid leaks: critical review and surgical considerations. Laryngoscope 2004;114: Colquhoun IR. CT cisternography in the investigation of cerebrospinal fluid rhinorrhea. Clin Radiol 1993;47: Manelfe C, Cellerier P, Sobel D, Prevost C, Bonafe A. Cerebrospinal fluid rhinorrhea: evaluation with mertizamide cisternography. Am J Roentgenol 1982;138: Wakhloo AK, van Velthoven V, Schumacher M, Krauss JK. Evaluation of MR imaging, digital subtraction cisternography, and CT cisternography in diagnosing CSF fistula. Acta Neurochir (Wien) 1991;111: Glaubitt D, Haubrich J, Cordini-Votsas M. Detection and quantitation of intermittent CSF rhinorrhea during prolonged cisternography with 111 In-DTPA. Am J Neuroradiol 1983;4: Stone JA, Castillo M, Neelon B, Mukherji SK. Evaluation of CSF leaks: high-resolution CT compared with contrast-enhanced CT and radionuclide cisternography. Am J Neuroradiol 1999;20: McKusick KA. The diagnosis of traumatic cerebrospinal fluid rhinorrhea. J Nucl Med 1977;18: Flynn BM, Butler SP, Quinn RJ, McLaughlin AF, Bautovich GJ, Morris JG. Radionuclide cisternography in the diagnosis and management of cerebrospinal leaks: the test of choice. Med J Aust 1987;146: Barrs DM, Kern EB. Use of intranasal pledgets for localization of cerebrospinal fluid rhinorrhea. (notes on technique). Rhinology 1979;42: Oberson R. Radioisotopic diagnosis of rhinorrhea. Radiol Clin Biol 1972;41: Shreve PD. Adding structure to function. J Nucl Med 2000;41: Wahl RL, Quint LE, Cieslak RD, Aisen AM, Koeppe RA, Meyer CR. Anatometabolic tumor imaging: fusion of FSG PET with CT or MRI to localize foci of increased activity. J Nucl Med 1993;34: Hutton BF, Braun M. Software for image registration: algorithms, accuracy, efficacy. Semin Nucl Med 2003;3: Slomka PJ. Software approach to merging molecular with anatomic information. J Nucl Med 2004;45:36S- 45S. 24. Mongioj V, Brusa A, Loi G, et al. Accuracy evaluation of fusion of CT, MR, and spect images using commercially available software packages (SRS PLATO and IFS). Int J Radiat Oncol Biol Phys 1999;43: Treves ST. Mitchell LD, Habboush IH. Three dimensional image alignment, registration and fusion. Q J Nucl Med 1998;42: Ann Nucl Med Sci 2006;19: Vol. 19 No. 4 December

5 SPECT MR SPECT cisternography and MRI fusion image of CSF leakage , -99m-DTPA ;19: (02) (02) lucky@tpech.gov.tw 2006;19: