|Year : 2019 | Volume
| Issue : 2 | Page : 394-397
Magnetic resonance imaging-guided transperineal prostate biopsy
Jie Chen, Zhengyu Lin, Jin Chen, Qingfeng Lin, Jian Chen, Yuan Yan
Department of Intervention, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
|Date of Web Publication||1-Apr-2019|
Dr. Zhengyu Lin
Department of Intervention, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of the study is to assess the clinical value of magnetic resonance imaging (MRI)-guided transperineal prostate biopsy in the diagnosis of prostate disease.
Materials and Methods: The institutional ethics committee approved this study. MRI-guided transperineal prostate biopsy was performed on 78 patients who had presented to our hospital with a prostate-specific antigen level >4 ng/mL or with MRI scans suggesting prostate cancer between January 2015 and August 2017. Written informed consent was obtained from all patients.
Results: Of the 78 patients, pathological diagnosis could not be carried out in one because insufficient prostate tissue was obtained during biopsy. Prostate adenocarcinoma was confirmed in 34 patients, small-cell neuroendocrine carcinoma in 1 patient, prostatic tuberculosis in 1 patient, and benign prostatic hyperplasia in 41 patients. These diagnoses were confirmed by surgical pathology in 31 patients, and all results were consistent with the biopsy pathology, with no false positives. Postoperative urinary tract infection occurred in one patient, and mild postoperative hemorrhage around the prostate gland was seen in 65 patients, without the need for further clinical treatment.
Conclusion: MRI-guided transperineal prostate biopsy is helpful in the diagnosis and treatment of prostatic disease.
Keywords: Biopsy, magnetic resonance imaging guided, prostate, transperineal
|How to cite this article:|
Chen J, Lin Z, Chen J, Lin Q, Chen J, Yan Y. Magnetic resonance imaging-guided transperineal prostate biopsy. J Can Res Ther 2019;15:394-7
| > Introduction|| |
As life expectancy and a westernized lifestyle have increased, prostate cancer has become common in men, especially in developed areas. Early diagnosis of prostate cancer is crucial to ensure timely treatment and prolong survival time. Significantly elevated prostate-specific antigen (PSA) is a sensitive diagnostic indicator of prostate cancer,, although it is less specific in the differential diagnosis of prostate hyperplasia, prostatitis, and prostate cancer. Therefore, pathological examination of biopsy remains the gold standard for prostate cancer diagnosis.
In the present study, magnetic resonance imaging (MRI)-guided transperineal prostate biopsy was performed in patients with suspected prostate cancer to allow pathological diagnosis and assess the clinical value of the procedure.
| > Materials and Methods|| |
We enrolled a total of 78 patients (age: 31–83 years and mean: 67.6 ± 8.73 years) in good general health who had presented to our hospital with a PSA level >4 ng/mL or MRI examination suggesting prostate cancer between January 2015 and August 2017. MRI-guided transperineal prostate biopsy was performed on patients who had no contraindications to MRI or biopsy. The ethics committee for research involving human participants at our university approved this study. Written informed consent was obtained from all patients.
Instruments and related parameters
A 1.5T GE Signa Infinity TwinSpeed MIR System coil was used for heart imaging (cannula probe: TTZ 16GX150 mm, Suzhou i-med; fast-spoiled gradient-recalled echo (fSPGR) T1-weighted imaging (T1WI): repetition time (TR) – 185 ms, echo time (TE) – 4.0 ms, flip angle (FA) – 85°, number of acquisition (NAQ) – 0.5, layer thickness (ST) – 5 mm, field of view (FOV) 34 cm – 25 cm, and scanning time (T) – 18 s; fast-recovery fast-spin echo (FR-FSE) T2-weighted imaging (T2WI): TR – 4000 ms, TE – 88 ms, FA – 90°, NAQ – 4, ST – 5 mm, FOV – 36 cm × 27 cm, and T – 48 s; and scanning direction: oblique coronal and oblique sagittal planes parallel to the puncture needle, as well as conventional transversal plane.
After routine preoperative enema and urethral catheterization, patients were placed in the lithotomy position with their penis and testicles fixed outside the operation field using tape. To conduct routine FS T1WI scanning, the perineum was labeled using Vitamin E capsules and the surgical area was disinfected using routine technique. Next, the area was covered using surgical towels, and local anesthesia was carried out. Puncture into the prostate was achieved using two 16G MRI-compatible needles under MRI guidance. The puncture direction and depth were monitored by repeated scanning during the procedure, and such regions as the urethra, rectum, pubis, and root of the penis were circumvented. Once the needle tip had reached the target, a core was withdrawn, and an 18G semi-automatic biopsy needle was inserted into in. A total of eight tissues were then obtained from the anterior prostatic apex, posterior prostatic apex, anterior base, and posterior base. These were fixed using formalin and evaluated. If necessary, an additional biopsy was performed at suspected foci of the previous MRI examination. After surgery, FSE T2WI MRI scans were performed. The patients were assessed for hemorrhage and for injury to the bladder, urethra, and rectum. A roll of paper was placed below the perineum to effect hemostasis, with the patient in the sitting position.
The diameter of the puncture needle in each image of the sequences taken during surgery was measured using a picture archiving and communication system.
| > Results|| |
Of the 78 patients who had undergone prostate biopsy, pathological diagnosis could not be performed in one because insufficient prostate tissue was obtained. [Table 1] lists the PSA, MRI, and pathological findings from the remaining 77 patients. The diagnosis was confirmed by surgical pathology in 31 patients, and biopsy pathology was consistent with this diagnosis in all cases – no false positives were found. In the follow-up MRI 1–2 years after the operation, pathological findings of benign hyperplasia were reported; no malignant signs were found. Biopsy was conducted with success rate of 98.7%. In one patient, a urinary tract infection was detected 2 days after the operation and was treated using antibiotics. Postoperative scanning showed mild postoperative hemorrhage around the prostate in 65 patients, none of whom showed any evidence of progression during short-term observation. Thus, no clinical treatment was required in this regard.
|Table 1: Comparison of prostate-specific antigen and magnetic resonance imaging among pathological types of transperineal prostate biopsy|
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The puncture needle appeared as a low signal in each image, with the needle tip manifesting as a slightly inflated low signal [Figure 1]b,[Figure 1]c,[Figure 1]d. The average diameter of the puncture needle was 3.37 ± 1.49 mm in the T1 sequences and 1.66 ± 0.23 mm in the T2 sequences. A paired-sample t-test was conducted using SPSS version 19.0 statistical software (IBM Corp., Armonk, NY, USA), and the results showed a significant difference between these sequence types (P < 0.05).
|Figure 1: Axial (a) fast-recovery fast-spin echo T2-weighted magnetic resonance images show a low-signal-intensity nodule (indicated by the white arrow) on the peripheral zone of prostate of high-signal intensity. Coronal (b) fsPGR T1-weighted magnetic resonance images show puncture needle presented as a clear low-signal-intensity streak (indicated by the white arrow). Sagittal (c) and coronal (d) fast-recovery fast-spin echo T2-weighted magnetic resonance images show relationship of position between the puncture needle and prostate (indicated by the white arrow)|
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| > Discussion|| |
At present, the routine method of prostate biopsy adopts the ultrasound-guided transrectal approach even though MRI-guided prostate biopsy exhibits certain advantages. In 2000, D'Amico and Cormack independently reported individual cases of transperineal prostate biopsy using a puncture template under the guidance of 0.5T interventional MRI., MRI allows the physical, biochemical, and functional characteristics of the inspected tissue to be assessed. It has advantages over other guiding methods because it shows good resolution of soft tissue, involves angiography without contrast agent, requires no ionizing radiation, and images multiple regions and planes. Moreover, MRI-guided prostate biopsy can clearly distinguish each zone of the prostate: low-intensity signal occurs in the central zone, whereas high-intensity signal occurs in the peripheral zone under TW2I. This allows the differential diagnosis of benign prostatic hyperplasia and prostate carcinoma, which occur in different areas because foci and structures around the urethra are clearly presented. Typically, prostate carcinoma presents as low-intensity signal nodules with a peripheral zone of high-intensity signals under TW2I [Figure 1]a, significantly high-intensity signals under diffusion-weighted imaging, limited apparent diffusion coefficient, significantly enhanced foci with dynamic enhancement, and significantly higher Cho peaks or increased (Cho + Cre)/Cit ratio under MR spectroscopy. It follows that the prostate foci were properly sampled in the study.
Zhihua et al. reported that the complication incidence was significantly higher after transrectal prostate biopsy (53.4%) than after transperineal (22.7%). Of the 78 patients in the present study, 65 experienced mild intraoperative hemorrhage without the need for further clinical treatment. The relative higher hemorrhage incidence is related to the sensitivity of MRI to blood.
Researchers in the Medical College of the University of London investigated specimens from patients with prostate carcinoma confirmed by transrectal biopsy who had undergone radical prostatectomy. They found that the incidence of carcinoma in the anterior region (21%) was significantly lower than that in the posterior (57%), probably because carcinoma in the anterior region tends to be missed by transrectal biopsy. This phenomenon has been called “prostatic evasive anterior tumor syndrome.” From this point of view, transperineal prostate biopsy is superior to transrectal. A survey from Switzerland involving >3000 patients who had undergone transrectal prostate biopsy revealed that postoperative urinary tract infection occurred in 6% of patients and that 1% patients had to be hospitalized due to complications of the infection, most often Escherichia More Details coli infection. In the present study, urinary tract infection was only detected in one patient, giving an incidence of about 1.28%, probably because the possibility of infection is decreased in procedures not involving the rectum.
In the present study, the simultaneous use of two MRI-compatible needles parallel to either side of the perineum somewhat reduced the operation time and the probability of urethral injury. The puncture needle was parallel to the main magnetic field (B0), as the perineum was approached with the patient in the lithotomy position. With regard to the passive display of MRI-compatible instruments, greater B0 angles lead to greater artifacts. The minimum artifact of the puncture needle was obtained, with an angle of 0° between the needle and B0. Owing to the 180°-inverted pulse in the conventional spin echo sequence, MRI-compatible metal is insensitive to magnetic field heterogeneity. This causes a small needle artifact and thus unclear presentation of the needle in the image. In the present study, the puncture procedure was guided by MRI using fSPGR T1WI, so it had the advantage of clear needle artifact and decreased scanning time. Puncture was carried out under the guidance of MRI (T1WI sequence), wherein the external diameter of the 16G MRI-compatible puncture needle was about 1.65 mm and was displayed in slight magnification. When the puncture needle was inadequately positioned, the T2WI sequence was used to identify the position of the puncture needle with respect to focus, as the diameter of the needle rendered with the T2WI sequence is relatively accurate.
The disadvantages of MRI-guided puncture include its high cost, as well as its many contraindications in patients with claustrophobia, metal implants, or artificial cardiac pacemakers. In addition, compared with ultrasound or computed tomography-guided puncture, this procedure lasts longer and entails more complex steps involving magnetically-compatible instruments and monitoring devices. Furthermore, the surgeon must be familiar with MRI and special sequences. The patients in the present study were placed in the lithotomy position with incomplete perineal exposure and limited abduction. This was necessitated by the smaller operation space provided by the conventional MRI used in the study. The operation duration was also prolonged due to repeated scanning.
| > Conclusion|| |
MRI-guided transperineal prostate biopsy has advantages over conventional prostate biopsy, particularly in the diagnosis and treatment of small foci. With the evolution of interventional MRI technology, this method will be increasingly accepted as safety improves and fewer complications are reported.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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