code: def get_b_matrix(csa_dict):
      vals = get_vector(csa_dict, "B_matrix", 6)
      if vals is None:
          return
      # the 6 vector is the upper triangle of the symmetric B matrix
      inds = np.array([0, 1, 2, 1, 3, 4, 2, 4, 5])
      B = np.array(vals)[inds]
      return B.reshape(3, 3)
  
file_path: nibabel/nibabel/nicom/csareader.py
imports: import numpy
  from .structreader import Unpacker
  from .utils import find_private_section
label_desc: Use image node_id 9 for calling a global function with example usage: get_b_matrix(csa_dict) and returns: B