Investigating the role of SPECT/CT in dynamic sentinel lymph node biopsy for penile cancers.
OBJECTIVE
Currently, most centres use 2-D planar lymphoscintigraphy when performing dynamic sentinel lymph node biopsy in penile cancer patients with clinically impalpable inguinal nodes. This study aimed to investigate the role of SPECT/CT following 2-D planar lymphoscintigraphy (dynamic and static) in the detection and localization of sentinel lymph nodes in the groin.


METHODS
A qualitative (visual) review was performed on planar followed by SPECT/CT lymphoscintigraphy in 115 consecutive patients (age 28-86 years) who underwent injection of99mTc-nanocolloid followed by immediate acquisition of dynamic (20 min) and early static scans (5 min) initially and further delayed static (5 min) images at 120 min followed by SPECT/CT imaging. The lymph nodes detected in each groin on planar lymphoscintigraphy and SPECT/CT were compared.


RESULTS
A total of 440 and 467 nodes were identified on planar scintigraphy and SPECT/CT, respectively. Overall, SPECT/CT confirmed the findings of planar imaging in 28/115 cases (24%). In the remaining 87 cases (76%), gross discrepancies were observed between planar and SPECT/CT images. SPECT/CT identified 17 instances of skin contamination (16 patients, 13%) and 36 instances of in-transit lymphatic tract activity (24 patients, 20%) that had been interpreted as tracer-avid lymph nodes on planar imaging. In addition, SPECT/CT identified 53 tracer-avid nodes in 48 patients (42%) that were not visualized on planar imaging and led to reclassification of the drainage basins (pelvic/inguinal) of 27 tracer-avid nodes.


CONCLUSIONS
The addition of SPECT/CT improved the rate of detection of true tracer-avid lymph nodes and delineated their precise (3-D) anatomic localization in drainage basins.
Department of Nuclear Medicine, University College Hospitals London, London, UK.|Institute of Nuclear Medicine, 5th Floor,, UCLH NHS Foundation Trust, 235 Euston Road, London, NW1 2BU, UK.
Ziauddin Zia
ZZ
Saad
Department of Urology, University College Hospitals London, London, UK.
Savvas
S
Omorphos
Department of Nuclear Medicine, University College Hospitals London, London, UK.
Sofia
S
Michopoulou
Department of Nuclear Medicine, University College Hospitals London, London, UK.
Svetislav
S
Gacinovic
Department of Urology, University College Hospitals London, London, UK.
Peter
P
Malone
Department of Urology, University College Hospitals London, London, UK.
Raj
R
Nigam
Department of Urology, University College Hospitals London, London, UK.
Asif
A
Muneer
Department of Nuclear Medicine, University College Hospitals London, London, UK. jamshed.bomanji@uclh.nhs.uk.|Institute of Nuclear Medicine, 5th Floor,, UCLH NHS Foundation Trust, 235 Euston Road, London, NW1 2BU, UK. jamshed.bomanji@uclh.nhs.uk.
Jamshed
J
Bomanji
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D010412:Penile Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D021701:Sentinel Lymph Node Biopsy; D000072098:Single Photon Emission Computed Tomography Computed Tomography
Cancer of the penis; Drainage basin; Planar lymphoscintigraphy; SPECT/CT lymphoscintigraphy; Sentinel node